苯氧基钇/二醇体系引发ε-已内酯开环聚合：实验与DFT计算
|
摘要
本文将苯氧基钇Y(OC_6H_5)_3作为催化剂用于催化ε-己内酯(CL)开环聚合,结果表明在80℃以上,60 min能够引发CL聚合,Y(OC_6H_5)_3有较高催化活性,单体和催化剂摩尔比[CL]/[Y]可以达到300。产物PCL的分子量M_n随着投料比[CL]/[Y]的增加而增加,PCL的SEC曲线为单峰,分子量分布为1.40-1.74。
将1,2-丙二醇引入催化体系,Y(OC6H5)3和1,2-丙二醇原位生成的烷氧基钇引发CL聚合呈现出活性开环聚合的特点。研究表明甲苯溶液中,100℃,60 min,聚合产率都在95%以上。投料比[OH]/[Y]由8.7逐步变为28.9时,聚合产物PCL的数均分子量M_(n,NMR)与理论计算值M_(n,cal)基本吻合。产物PCL的分子量分布比较窄(MWD=1.10-1.29)。固定[CL]/[OH]比值,随着[OH]/[Y]比例的增大,PCL的M_n几乎没有变化,说明产物的分子量由二醇的用量控制,而与催化剂的浓度无关。因此设计聚合反应中的投料比,改变二醇的加入量,可以制备预定分子量的PCL。当[OH]/[Y]的投料比达到28.9时,CL的聚合反应仍保持活性聚合的特点,表明聚合物的活性链端Y-OR和休眠的羟基端基之间H-OR的交换速率非常高。
运用MALDI-TOF、~1H NMR、~(13)C NMR、~1H-~1H COSY和~1H-~(13)C HMQC分析方法,确认了聚合产物中CL链节、链端基和引发剂二醇片断上的每种氢和碳原子在NMR上所对应信号的精确化学位移和归属,并据此确定产物的结构,证明1,2-丙二醇的伯羟基和仲羟基能够同时引发CL聚合。
本文深入研究了Y(OC_6H_5)_3/1,2-丙二醇体系引发CL聚合机理。用密度泛函理论(DFT)方法研究了CL插入Y-OCH3活性中心的链增长机理。计算得到了反应过程所涉及的各个反应物、中间体、过渡态和产物的优化几何构型及其Gibbs自由能,证明了CL插入Y-OCH_3经过4步基元反应。首先是CL环上羰基与Y活性中心配位,实现羰基加成反应。随着分子内烷氧基配体交换,CL环上酰氧键断裂,完成了一个CL单体的插入过程。其中,第一步单体羰基加成形成五配位Y配合物即过渡态TS,是整个单体插入历程中决定速度的步骤,298 K时的活化Gibbs自由能△G~≠=+23.1 kcal/mol。中间体3和4的偶极距比反应物2和产物5小,说明低极性的溶剂能够稳定中间体3和4,从而加速CL插入反应,有利于聚合反应的进行。钇活性中心与聚合物链末端活泼氢之间的交换反应△G~≠为+3.0 kcal/mol,运用过渡态理论推导绝对反应速率常数,可以证明链交换反应比链增长反应快4.25×10~(12)倍,表明烷氧基钇和体系中的过量羟基能够发生活性中心的快速转移,实现CL的活性聚合。
Y(OC_6H_5)3/1,2-丙二醇体系引发CL聚合时的Y活性中心与活泼氢交换反应有三种:不同聚合物链末端的氢交换、不同1,2-丙二醇之间伯羟基和仲羟基的氢交换,同一个1,2-丙二醇的伯羟基和仲羟基的交换,它们在373 K时的活化Gibbs自由能分别是3.0 kcal/mol、3.6 kcal/mol和18.5 kcal/mol,三种氢交换反应速率分别比CL的增长反应速率快4.25×10~(12),3.56×10~(12),3.85×10~3倍,说明无论是分子内还是分子间的交换反应都比CL增长速率快得多,因此CL根本没有机会选择在哪种羟基上增长,即CL在伯仲羟基上选择增长的概率是相同的,这就证明了Y(OC_6H_5)_3/1,2-丙二醇体系引发CL聚合的产物是由伯仲羟基同时引发聚合得到。
本文还研究了Y(OC_6H_5)_3/乙二醇体系、Y(OC_6H_5)_3/1,3-丙二醇体系催化CL开环聚合,聚合物均为二醇的嵌入式结构,即乙二醇(或1,3-丙二醇)中的两个伯羟基具有相同的活性,能够同时引发CL聚合。
综上所述,Y(OC_6H_5)_3/二醇体系引发CL开环聚合时,实验和计算结果都证明了二醇中的伯羟基和仲羟基都能够同时引发CL聚合。
Yttrium triphenolate [Y(OC_6H_5)_3] was studied in the ring-openingpolymerization (ROP) of e-carprolactone (CL). It was found that Y(OC_6H_5)_3 alonecould initiated the ROP of CL in 60 min at the temperature higher than 80℃. and thatit had good catalytic activity with the [CL]/[Y] ratio of 300. Although thepolymerization was not a living process, the molecular weight (M_n) of PCL increasedwith increasing the molar ratio of CL and Y(OC_6H_5)_3. The SEC curves weremonomodal and molecular weigth distribution (MWD) was moderate between 1.40and 1.74.
When 1,2-propanediol was introduced, active species of yttrium alkoxides was insitu generated by the reaction of Y(OC_6H_5)_3 and 1,2-propanediol and thepolymerization exhibited a living characteristic. Polymerization of CL was carried outin toluene, achieving high yields (>95%) in 60 min at 100°C. When feed ratio[OH]/[Y] increasing from 8.7 to 28.9, the M,, values of the produced PCL calculatedby ~1H NMR analyses met the theoretical results quite well and the MWD data werereasonably narrow between 1.10 and 1.29. When the molar ratio of [OH]/[Y] wasfixed, the M_n value of obtained PCL was almost unchanged with the increasing ofmolar ratio of [OH]/[Y]. Therefore, M_n of PCL was controlled by adjusting the ratioof CL and 1,2-propanediol and independent with the concentration of Y(OC_6H_5)_3.Moreover, we found a living CL polymerization when the ratio of [OH]/[Y] reachedas high as 28.9 indicating an extremely fast exchange reaction between active chainend Y-OR and dormant hydroxyl end group H-OR.
The structure of PCL initiated by 1,2-propanediol and Y(OC_6H_5)_3 was obtainedaccording to MALDI-TOF, ~1H NMR, ~(13)C NMR, ~1H-~1H COSY and ~1H-(13)C HMQCanalyses. All proton and carbon atoms in the backbone, the end groups and theinitiator 1,2-propanediol residue of the obtained PCL were fully characterized. As theconclusion, both the primary and secondary hydroxyl groups of 1,2-propanediolmolecules initiated the ROP of CL simultaneously.
The mechanism of polymerization of CL initiated by Y(OC_6H_5)_3 and 1,2-propanediol system was studied. The propagation mechanism of s-caprolactone(CL) insertion into Y-OCH_3 bond was investigated using density functional theory(DFT) calculations. The optimized geometries and corresponding Gibbs free energiesof the reactants, intermediates, transition states and products were obtained, whichconfirmed a four-step coordination-insertion mechanism.The coordination of CL ontoyttrium center led to a nucleophilic addition of the carbonyl group of CL, and then anintramolecular alkoxide ligand exchange reaction occured. A monomer insertion wascompleted by the CL ring opening via acyl-oxygen bond cleavage. The formation oftransition state TS, the five-coordinated yttrium complex, was found to be the ratedetermining step whose active Gibbs free energy△G~≠at 298 K was +23.1 kcal/mol.The dipole moment values of intermediates 3 and 4 were smaller than those of reagent2 and product 5. Therefore, a solvent with low polarity stabilized 3 and 4 and a fastCL insertion reaction could be expected.△G~≠of intermolecular exchange reactionbetween yttrium alkoxide active center and free hydroxyl end group was +3.0kcal/mol. According to the transition state theory, intermolecular exchange reactionwas 4.25×10~(12) times faster than chain propagation reaction. Therefore, yttriumalkoxide active center transfered extremely fast from one free hydroxyl end group toanother, which resulted in the living behavior of the CL ROP.
During the CL polymerization initiated by Y(OC_6H_5)_3 and 1,2-propanediol, thehydroxyl groups involved in the exchange reaction with active Y-OR center includedthe primary hydroxyl groups of the dormant polymer chain ends and the primary andsecondary hydroxyl groups of the excess 1,2-propanediol molecules. Three kinds ofmodel reactions were calculated by DFT method and their△G~≠were 3.0 kcal/mol, 3.6kcal/mol and 18.5 kcal/mol at 373 K, respectively. Hydrogen exchange reaction rateswere respectively 4.25×10~(12), 3.56×10~(12) and 3.85×10~3 times faster than chainpropagation reaction. Therefore, exchange reaction rates between different polymerchains or alcohols were much higher than CL propagation rate and thus the newcoming CL were not able to know which original hydroxyl group was the one it wasgoing to grow onto.
The initiating system of Y(OC_6H_5)_3 with ethylene glycol and 1,3-propanediolwere also studied and the produced polymer were diol-embedded PCL. The primary hydrogen of ethylene glycol (or 1,3-propanediol) exhibited the same activity andinitiated the ROP of CL.
In summary, experimental analyses and DFT calculations confirmed that bothprimary and secondary hydroxyl groups of diol molecules were able to initiate theROP of CL simultaneously in the presence of Y(OC_6H_5)_3 catalyst.
将1,2-丙二醇引入催化体系,Y(OC6H5)3和1,2-丙二醇原位生成的烷氧基钇引发CL聚合呈现出活性开环聚合的特点。研究表明甲苯溶液中,100℃,60 min,聚合产率都在95%以上。投料比[OH]/[Y]由8.7逐步变为28.9时,聚合产物PCL的数均分子量M_(n,NMR)与理论计算值M_(n,cal)基本吻合。产物PCL的分子量分布比较窄(MWD=1.10-1.29)。固定[CL]/[OH]比值,随着[OH]/[Y]比例的增大,PCL的M_n几乎没有变化,说明产物的分子量由二醇的用量控制,而与催化剂的浓度无关。因此设计聚合反应中的投料比,改变二醇的加入量,可以制备预定分子量的PCL。当[OH]/[Y]的投料比达到28.9时,CL的聚合反应仍保持活性聚合的特点,表明聚合物的活性链端Y-OR和休眠的羟基端基之间H-OR的交换速率非常高。
运用MALDI-TOF、~1H NMR、~(13)C NMR、~1H-~1H COSY和~1H-~(13)C HMQC分析方法,确认了聚合产物中CL链节、链端基和引发剂二醇片断上的每种氢和碳原子在NMR上所对应信号的精确化学位移和归属,并据此确定产物的结构,证明1,2-丙二醇的伯羟基和仲羟基能够同时引发CL聚合。
本文深入研究了Y(OC_6H_5)_3/1,2-丙二醇体系引发CL聚合机理。用密度泛函理论(DFT)方法研究了CL插入Y-OCH3活性中心的链增长机理。计算得到了反应过程所涉及的各个反应物、中间体、过渡态和产物的优化几何构型及其Gibbs自由能,证明了CL插入Y-OCH_3经过4步基元反应。首先是CL环上羰基与Y活性中心配位,实现羰基加成反应。随着分子内烷氧基配体交换,CL环上酰氧键断裂,完成了一个CL单体的插入过程。其中,第一步单体羰基加成形成五配位Y配合物即过渡态TS,是整个单体插入历程中决定速度的步骤,298 K时的活化Gibbs自由能△G~≠=+23.1 kcal/mol。中间体3和4的偶极距比反应物2和产物5小,说明低极性的溶剂能够稳定中间体3和4,从而加速CL插入反应,有利于聚合反应的进行。钇活性中心与聚合物链末端活泼氢之间的交换反应△G~≠为+3.0 kcal/mol,运用过渡态理论推导绝对反应速率常数,可以证明链交换反应比链增长反应快4.25×10~(12)倍,表明烷氧基钇和体系中的过量羟基能够发生活性中心的快速转移,实现CL的活性聚合。
Y(OC_6H_5)3/1,2-丙二醇体系引发CL聚合时的Y活性中心与活泼氢交换反应有三种:不同聚合物链末端的氢交换、不同1,2-丙二醇之间伯羟基和仲羟基的氢交换,同一个1,2-丙二醇的伯羟基和仲羟基的交换,它们在373 K时的活化Gibbs自由能分别是3.0 kcal/mol、3.6 kcal/mol和18.5 kcal/mol,三种氢交换反应速率分别比CL的增长反应速率快4.25×10~(12),3.56×10~(12),3.85×10~3倍,说明无论是分子内还是分子间的交换反应都比CL增长速率快得多,因此CL根本没有机会选择在哪种羟基上增长,即CL在伯仲羟基上选择增长的概率是相同的,这就证明了Y(OC_6H_5)_3/1,2-丙二醇体系引发CL聚合的产物是由伯仲羟基同时引发聚合得到。
本文还研究了Y(OC_6H_5)_3/乙二醇体系、Y(OC_6H_5)_3/1,3-丙二醇体系催化CL开环聚合,聚合物均为二醇的嵌入式结构,即乙二醇(或1,3-丙二醇)中的两个伯羟基具有相同的活性,能够同时引发CL聚合。
综上所述,Y(OC_6H_5)_3/二醇体系引发CL开环聚合时,实验和计算结果都证明了二醇中的伯羟基和仲羟基都能够同时引发CL聚合。
Yttrium triphenolate [Y(OC_6H_5)_3] was studied in the ring-openingpolymerization (ROP) of e-carprolactone (CL). It was found that Y(OC_6H_5)_3 alonecould initiated the ROP of CL in 60 min at the temperature higher than 80℃. and thatit had good catalytic activity with the [CL]/[Y] ratio of 300. Although thepolymerization was not a living process, the molecular weight (M_n) of PCL increasedwith increasing the molar ratio of CL and Y(OC_6H_5)_3. The SEC curves weremonomodal and molecular weigth distribution (MWD) was moderate between 1.40and 1.74.
When 1,2-propanediol was introduced, active species of yttrium alkoxides was insitu generated by the reaction of Y(OC_6H_5)_3 and 1,2-propanediol and thepolymerization exhibited a living characteristic. Polymerization of CL was carried outin toluene, achieving high yields (>95%) in 60 min at 100°C. When feed ratio[OH]/[Y] increasing from 8.7 to 28.9, the M,, values of the produced PCL calculatedby ~1H NMR analyses met the theoretical results quite well and the MWD data werereasonably narrow between 1.10 and 1.29. When the molar ratio of [OH]/[Y] wasfixed, the M_n value of obtained PCL was almost unchanged with the increasing ofmolar ratio of [OH]/[Y]. Therefore, M_n of PCL was controlled by adjusting the ratioof CL and 1,2-propanediol and independent with the concentration of Y(OC_6H_5)_3.Moreover, we found a living CL polymerization when the ratio of [OH]/[Y] reachedas high as 28.9 indicating an extremely fast exchange reaction between active chainend Y-OR and dormant hydroxyl end group H-OR.
The structure of PCL initiated by 1,2-propanediol and Y(OC_6H_5)_3 was obtainedaccording to MALDI-TOF, ~1H NMR, ~(13)C NMR, ~1H-~1H COSY and ~1H-(13)C HMQCanalyses. All proton and carbon atoms in the backbone, the end groups and theinitiator 1,2-propanediol residue of the obtained PCL were fully characterized. As theconclusion, both the primary and secondary hydroxyl groups of 1,2-propanediolmolecules initiated the ROP of CL simultaneously.
The mechanism of polymerization of CL initiated by Y(OC_6H_5)_3 and 1,2-propanediol system was studied. The propagation mechanism of s-caprolactone(CL) insertion into Y-OCH_3 bond was investigated using density functional theory(DFT) calculations. The optimized geometries and corresponding Gibbs free energiesof the reactants, intermediates, transition states and products were obtained, whichconfirmed a four-step coordination-insertion mechanism.The coordination of CL ontoyttrium center led to a nucleophilic addition of the carbonyl group of CL, and then anintramolecular alkoxide ligand exchange reaction occured. A monomer insertion wascompleted by the CL ring opening via acyl-oxygen bond cleavage. The formation oftransition state TS, the five-coordinated yttrium complex, was found to be the ratedetermining step whose active Gibbs free energy△G~≠at 298 K was +23.1 kcal/mol.The dipole moment values of intermediates 3 and 4 were smaller than those of reagent2 and product 5. Therefore, a solvent with low polarity stabilized 3 and 4 and a fastCL insertion reaction could be expected.△G~≠of intermolecular exchange reactionbetween yttrium alkoxide active center and free hydroxyl end group was +3.0kcal/mol. According to the transition state theory, intermolecular exchange reactionwas 4.25×10~(12) times faster than chain propagation reaction. Therefore, yttriumalkoxide active center transfered extremely fast from one free hydroxyl end group toanother, which resulted in the living behavior of the CL ROP.
During the CL polymerization initiated by Y(OC_6H_5)_3 and 1,2-propanediol, thehydroxyl groups involved in the exchange reaction with active Y-OR center includedthe primary hydroxyl groups of the dormant polymer chain ends and the primary andsecondary hydroxyl groups of the excess 1,2-propanediol molecules. Three kinds ofmodel reactions were calculated by DFT method and their△G~≠were 3.0 kcal/mol, 3.6kcal/mol and 18.5 kcal/mol at 373 K, respectively. Hydrogen exchange reaction rateswere respectively 4.25×10~(12), 3.56×10~(12) and 3.85×10~3 times faster than chainpropagation reaction. Therefore, exchange reaction rates between different polymerchains or alcohols were much higher than CL propagation rate and thus the newcoming CL were not able to know which original hydroxyl group was the one it wasgoing to grow onto.
The initiating system of Y(OC_6H_5)_3 with ethylene glycol and 1,3-propanediolwere also studied and the produced polymer were diol-embedded PCL. The primary hydrogen of ethylene glycol (or 1,3-propanediol) exhibited the same activity andinitiated the ROP of CL.
In summary, experimental analyses and DFT calculations confirmed that bothprimary and secondary hydroxyl groups of diol molecules were able to initiate theROP of CL simultaneously in the presence of Y(OC_6H_5)_3 catalyst.
引文
[1] Amass W.; Amass A.; Tighe B., A review of biodegradable polymers, Polymer International 1998,47(2), 89-144.
[2] Okada M., Chemical syntheses of biodegradable polymers, Progress in polymer science, 2002,27,87-133.
[3] Mochizuki M., Nakayama K., Qian R. Y, Jiang B. Z, Hirami M, Hayashi T., Masuda T.,Nakajima A., Studies on biodegradable poly(hexano-6-lactone) fibers 1. Structure and properties of drawn poly(hexano-6-lactone) fibers, Pure and applied chemistry, 1997, 69(12) 2567-2575.
[4] Shen Y. Q.; Sun W. L.; Shen Z. Q., Regulation of biodegradability and drug release behavior of aliphatic polyesters by blending. Journal of Biomedical Materials Research, 2000, 50(4), 528.
[5] Wang J. L., Wang L., Dong C.M., Synthesis, crystallization, and morphology of star-shaped poly(ε-caprolactone), Journal of Polymer Science Part A: Polymer Chemistry 2005,43(22), 5449.
[6] Feng H., Dong C.M., Preparation and characterization of chitosan-graft-poly (e-caprolactone) with an organic catalyst, Journal of Polymer Science Part A: Polymer Chemistry, 2006, 44(18),5353.
[7] Kricheldorf H. R.; Jonte J. M.; Dunsing R., Polylactones, 7 The mechanism of cationic polymerization of ε-propiolactone and ε-caprolactone, Makromolekulare Chemie, 1986, 187(4),771-785.
[8] Cherdron H., Ohse H., Korte F., The polymerization of lactones. I. Homopolymerization of 4-,6-, and 7-membered lactones with cationic initiators, Makromolekulare Chemie, 1962, 56, 179.
[9].Ludvig E. B., Beleukaya B. C. C., Mechanism of cationic polymerization of ε-caprolactone, J.Macromol. Sci. Chem, 1974, 8(4), 819.
[10] Hofman A., Slomkowski S., Penczek S., Structure of active species in the cationic polymerization of ε-propiolactone and ε-caprolactone, Makromolekulare Chemie, 1984, 185, 655.
[11] Okamoto Y., Cationic ring-opening polymerization of lactones in the presence of alcohol,Makromol. Chem. Macromol. Symp, 1991, 42, 117.
[12] Shibasaki Y., Sanda H., Yokoi M., Sanda F., Endo T., Application to well-defined block copolymer synthesis with seven-membered cyclic carbonate, Macromolecules, 2000, 33(12),4316-20.
[13] Endo T., Shibasaki Y., Sanda F., Controlled ring-opening carbonates polymerization of cyclic carbonates and lactones by an activated monomer mechanism, Journal of Polymer Science Part A:Polymer Chemistry, 2002, 13, 2190.
[14] Nomura N., Taira A., Tomioka T., A catalytic approach for cationic living polymerization:Sc(OTf)_3-catalyzed ring-opening polymerization of lactones, macromolecules, 2000, 33, 1497.
[15] Gazeau-Bureau S., Delcroix D., Martin-Vaca B., Organo-catalyzed ROP of e-caprolactone: Methanesulfonic acid competes with trifluoromethanesulfonic acid, macromolecules, 2008, 41(11),3782.
[16] Nomura N., Taira A., Nakase A,, et al.. Ring-opening polymerization of lactones by rare-earth metal triflates and by their reusable system in ionic liquids, tetrahedron, 2007, 63(35), 8478.
[17] Kim M. S., Seo K., S, Kliang G., Lee H., B., Ring-opening polymerization of epsilon-caprolactone by poly(ethylene glycol) by an activated monomer mechanism,macromolecular rapid communications, 2005, 26(8), 643.
[18] Oh J. M., Lee S. H., Son J. S., Kim M. S., Ring-opening polymerization of epsilon-caprolactone by poly(propyleneglycol) in the presence of a monomer activator, polymer,2009,50(25), 6019.
[19] Basko M., Kubisa P., Cationic copolymerization of epsilon-caprolactone and L,L-lactide by an activated monomer mechanism, Journal of Polymer Science Part A: Polymer Chemistry, 2006,44(24), 7071.
[20] Basko M., Kubisa P., Polyester oligodiols by cationic AM copolymerization of L,L-lactide and epsilon-caprolactone initiated by diols, Journal of Polymer Science Part A: Polymer Chemistry, 2007, 45(14), 3090.
[21] Gowda R. R., Chakraborty D., Environmentally benign process for bulk ring opening polymerization of lactones using iron and ruthenium chloride catalysts, journal of molecular catalysis A: chemical, 2009, 301(1-2), 84.
[22] Lofgren A., Albertsson A.-C., Dubois P., Jerome R., Recent advances in ring-opening polymerization of lactones and related compounds, Journal of Molecular Science Rev Macromolcular Chemical Physics, 1995, 35, 379.
[23] Kuhling S., Keul H., Hocker H., Copolymerization of 2,2-dimethyltrimethylene carbonate with 2-allyloxyinethyl-2-ethyltrimethylene carbonate and with ε-caprolactone using initiators on the basis of Li, Al, Zn and Sn, Makromolecular Chemistry, 1992, 193, 1207.
[24] Wurm B., Keul H., Hocker H., Dibutylmagnesium-an initiator for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate and e-Caprolactone, Makromolecular Chemical Rapid Communication 1992, 13,9.
[25] Gitsov I, Rashkov I. B, Panayotov I. M, Anionic polymerization of lactones initiated by alkali graphitides. V. Initiation mechanism and nature of the active centers, Journal of Polymer Science Part A: Polymer Chemistry, 1990, 28, 2115.
[26] Ito K., Hashizuka Y., Yamashita Y., Equilibrium Cyclic Oligomer Formation in the Anionic Polymerization of ε-Caprolactone, Macromolecules, 1977, 10, 821.
[27] Ito K., Yamashita Y., propagation and Depropagation Rates in the Anionic Polymerization of ε-Caprolactone Cyclic Oligomers, Macromolecules, 1978,11(1), 68.
[28] Stere C., Lovu M. C., Lovu H., Boborodea, A., Vasilescu DS, Read SJ, Anionic and Ionic Coordinative Polymerization of Caprolactone, Polymer Advanced Technologies, 2001, 12,300-305.
[29] Gitsov I., Rashkov I., Panayotov I. M., Golub A., Anionic polymerization of lactones initiated by alkali graphitides IV.copolymerization of ε-caprolactone initiated by KC24, Journal of Polymer Science Part A: Polymer Chemistry, 1989, 27(2), 639.
[30] Gitsov I., Ivanova P. T., Frechet J. M. J, Dendtimers as macroinitiators for anionic ring-opening polymerization of epsilon-caprolactone, macromolecular rapid communications, 1994, 15(5), 387-393.
[31] Albertsson A. C., Varnia I. K., Recent developments in ring opening polymerization of lactones for biomedical applications, Biomacromolecules, 2003,4, 1466-1486.
[32] Duda A., Kowalski A., Penczek S., Uyama H., Kobayashi S., Kinetics of the ring-opening polymerization of 6-, 7-, 9-, 12-, 13-, 16-, and 17-membered lactones. comparison of chemical and enzymatic polymerizations, Macromolecules, 2002, 35,4266-4270.
[33] Uyama H., Takeya K.., Kobayashi S., Enzymic ring-opening polymerization lactones to polyesters by lipase catalyst: unusually high reactivity of macrolides, Bull. Chem. Soc. Jpn. 1995,68,56-61.
[34] Kumar A., Gross R. A., Jendrossek D., Poly(3-hydroxybutyrate)-depolymerase from Pseudomonas lemoignei: catalysis of esterifications in organic media, Journal of Organic.Chemistry, 2000, 65,7800-7806.
[35] Ceccorulli G., Scandola M., Kumar A., Kalra, B. Gross R. A., Cocrystallization of random copolymers of ω-pentadecalactone and ε-caprolactone synthesized by lipase catalysis,Biomacromolecules, 2005, 6, 902-907.
[36] Kumar A., Kalra B., Dekhterman A., Gross R. A., Efficient ring-opening polymerization and copolymerization of ε-caprolactone and ω-pentadecalactone catalyzed by Candida antarctica lipase B, Macromolecules, 2000, 33, 6303-6309.
[37] Kumar A., Gross R. A., Candida antarctica lipase b-catalyzed transesterification: new synthetic routes to copolyesters, Journal of American Chemistry Society. 2000, 122, 11767-11770.
[38] Dong H., Wang H.-D., Cao S.-G., Shen J.-C., Lipase-catalyzed polymerization of lactones and linear hydroxyesters, Biotechnology Letter, 1998, 20, 905-908.
[39] Oishi M., Ikeo S., Nagasaki Y., Lipase-catalyzed selective synthesis and micellization of poly(ethylene glycol)-block-poly(ε-caprolactone) copolymer possessing a carboxylic acid group at the PEG chain end, Polymer Joumal(Tokyo, Japan), 2007, 39, 239-244.
[40] Duxbury C. J., Cummins D., Heise A., Selective enzymatic grafting by steric control,Macromolcular Rapid Communication, 2007, 28, 235-240.
[41] Zhou J., Wang W., Thurecht K. J., Villarroya S., Howdle S. M, Simultaneous dynamic kinetic resolution in combination with enzymatic ring-opening polymerization, Macromolecules, 2006, 39,7302-7305.
[42] Hans M., Gasteier P., Keul H., Moeller M., Ring-opening polymerization of e-caprolactone by means of mono- and multifunctional initiators: comparison of chemical and enzymatic catalysis,Macromolecules, 2006, 39, 3184-3193.
[43] Skaria S., Smet M., Frey H., Enzyme-catalyzed synthesis of hyperbranched aliphatic polyesters, Macromolcular Rapid Communication, 2002, 23, 292-296.
[44] Srivastava R.K., Albertsson A.-C., Porous scaffolds from high molecular weight polyesters synthesized via enzyme-catalyzed ring-opening polymerization, Biomacromolecules 2006, 7,2531-2538.
[45] Srivastava R. K., Albertsson A.-C., Enzyme-catalyzed ring-opening polymerization of seven-membered ring lactones leading to terminalfunctionalized and triblock polyesters,Macromolecules, 2006, 39,46-54.
[46] Srivastava R. K., Kumar K., Varma I. K., Albertsson A.-C., Chemoenzymatic synthesis of comb polymers, European Polymer Jounal, 2007,43, 808-817.
[47] Albertsson A.-C., Srivastava R. K., Recent developments in enzyme-catalyzed ring-opening polymerization, Advanced Drug Delivery Reviews, 2008, 60, 1077-1093
[48] Kricheldorf H. R, Sumbel M. V., Kreiser-Saunders I., Polylactones20.Polymerization of epsilon-caprolactone with tributylin derivatives: a mechanistic study, Macromolecules 1991, 24(8),1944.
[49.] Shen Y. Q., Shen Z. Q., Shen J. L., Zhang Y. F, Yao K. M., Characteristics and Mechanism of ε-Caprolactone Polymerization with Rare Earth Halide Systems, Macromolecules, 1996, 29, 3441.
[50] Shen Y. Q., Shen Z. Q., Shen J. L., Zhang Y. F., Huang Q. H., A comparison of mechanisms of ε-caprolactone and trimethylene carbonate with rare earth halides, Journal of Polymer Science Part A: Polymer Chemistry, 1997, 35, 1339-1352.
[51] Shen Y. Q., Huang Q. H., Shen Z. Q., Ramdom copolymerization of lactone and trimethylene carbonate with rare earth catalysts. Journal of Applied Polymer Science, 1997, 64, 2131-39.
[52] Ogawa A., Takami N., Sekiguchi M., Ryu I., Kambe N., Sonodo N., The first deoxygenative coupling of amides by an unprecedented samarium/samarium diiodide system, Journal of the American Chemical Society, 1992, 114, 8729-8730.
[53] Agarwal S., Brandukova-Szmikowski N. E., Greiner A., Reactivity of Sm(II) compounds as ring-opening polymerization initiators for lactones, Macromolecular Rapid Communication, 1999,20, 274-78.
[54] Agarwal S., Naumann N., Xie X. L., Synthesis and microstructural characterization of ethylene carbonate-ε-cprolactoneL-lactide copolymers using one- and two-dimensional NMR spectroscopy, Macromolecules, 2002, 35, 7713-7717.
[55] Agarwal S., Xie X. L., SmI_2/Sm-based γ-butyrolactone-ε-caprolactone copolymers:microstructural characterization using one- and two-dimensional NMR spectroscopy,Macromolecules, 2003, 36, 3545-3549.
[56] Gattin R., Cretu A., Denise B.-B., effect of the remaining lanthanide catalysts on the hydrolytic and enzymatic degradation of poly(ε-caprolactone), Macromol. Symp.2003, 197,455-466.
[57] Scott N. M., Schareina T., Tok O., Kempe R., Lithium and Potassium Amides of Sterically Demanding Aminopyridines, European Journal Inorganic Chemistry, 2004, 3297-3304.
[58] Scott N. M., Kempe R., Di- and Trivalent Lanthanide Complexes Stabilized by Sterically Demanding Aminopyridinato Ligands, European Journal Inorganic Chemistry, 2005, 1319-1324.
[59] Guillaume S. M., Schappacher M., Scott N. M., Kempe R., Di- and trivalent rare earth complexes stabilized by sterically demanding aminopyridinato ligands as initiators in ring-opening polymerization reactions of epsilon-caprolactone, Journal of Polymer Science Part A: Polymer Chemistry, 2007,45(16), 3611-3619.
[60] Deng X. M., Yuan M. L., Xiong C. D., Polymerization of lactide and lactones. Ring-opening polymerization of ε-caprolaetone and DL-lactide by organoacid compounds. Journal of Applied Polymer Science, 1999,71, 1941-1948.
[61] Zhang J., Gan Z. H., Zhong Z. Y, et al A novel rare earth coordination catalyst for polymerization of biodegradable aliphatic lactones and lactides, Polymer International, 1998, 45,60-66.
[62] Zhong Z. Y., Yu D. H., Meng F. H., et al. Controlled synthesis of L-lactide-b-ε-caprolactone block copolymers using a rare earth complex as catalyst. Polymer, Journal, 1999, 31, 633-636.
[63] Shen Z. Q., Chen X. H., Shen Y Q., et al. Ring-opening polymerization of ε-caprolactone by rare earth coordination catalysts. I. Characteristics, kinetics, and mechanism of ε-caprolactone polymerization with Nd(acac)_3 3H_2O-AlEt_3 system. Journal of Polymer Science Part A: Polymer Chemistry, 1994,32, 597-603.
[64] Kowalski A., Duda A., Penczek S., Mechanism of Cyclic Ester Polymerisation Initiated with Tin(II) Octoate 2. Macromolecules Fitted with Tin Alkoxide Species Observed Directly in MALDI-TOF Spectra, Macromolecules, 2000, 33(3), 689-695.
[65] Storey R. F., Sherman J. W., Kinetics and Mechanism of the Stannous Octoate-Catalyzed Bulk Polymerisation of ￡-Caprolactone, Macromolecules 2002, 35(5), 1504-1512.
[66] Kricheldorf H. R, Kreiser-Saunders I, Boettcher C, Polylactones: 31. Sn(II)octoate-initiated polymerization of L-lactide: a mechanistic study, Polymer, 1995, 36, 1253.
[67] Stjerndahl A., Finne-Wistrand A, Albertsson A.-C.,. Backesjo, C. M., Lindgren, U.,Minimization of residual tin in the controlled Sn(II)octoate-catalyzed polymerization of epsilon-caprolactone, Journal of biomedical materials research part A, 2008, 87, 1086-1091.
[68] Kowalski, A., Duda, A., Penczek, S., Kinetics and Mechanism of Cyclic Esters Polymerization Initiated with Tin(II) Octoate. 3. Polymerization of L, L-Dilactide Macromolecules, 2000, 33, 7359-7370.
[69] Kowalski A., Duba A., Libiszowski J., Penczek S., Kinetics and mechanism of cyclic esters polymerization initiated with Tin(II) octoate, Polymerization of caprolactone and L-lactide co-initiated with primary amines, Macromolecules, 2005, 38(21), 8170-6.
[70] Kowalski A., Libiszowski J., Majerska K., Duda A., Penczek S., Kinetics and mechanism of ￡-caprolactone and L,L-lactide polymerization coinitiated with zinc octoate or aluminum acetylacetonate: The next proofs for the general alkoxide mechanism and synthetic applications,Polymer, 2007, 48(14), 3952-3960.
[71] Wu R. Z., Al-Azemi T. F; Bisht K. S., One-Shot Block Copolymcrization of a Functional Seven-Membered Cyclic Carbonate Derived from L-Tartaric Acid with epsilon-Caprolactone,macromolecules, 2009, 42(7), 2401-2410.
[72] Jia Y. T., Shen X. Y., Gu X. H., Dong J., Mu C. X., Zhang, Y. Q., Synthesis and characterization of tercopolymers derived from epsilon-caprolactone, trimethylene carbonate,and lactide, polymer for advanced technologies, 2008, 19 (2), 159-166.
[73] Cheng J., Ding J. X., Wang Y. C., Wang J, Synthesis and characterization of star-shaped block copolymer of poly(epsilon-caprolactone) and poly(ethylethylene phosphate) as drug carrier,polymer, 2008, 49 (22), 4784-4790.
[74] Mahmud A., Xiong X. B., Lavasanifar A., Novel self-associating poly(ethylene oxide)-block-poly(epsilon-caprolactone) block copolymers with functional side groups on the polyester block for drug delivery, macromolecules, 2006, 39 (26), 9419-9428.
[75] He B., Chan-Park M. B., Synthesis and characterization of functionalizable and photopatternable poly(epsilon-caprolactone-co-RS-betamalicacid), macromolecules, 2005, 38 (20),8227-8234.
[76] Jacobs C., Dubois R., Jerome R., et al, Macromolecular engineering of polylactones and polylactides.5.Synthesis and characterization of diblock copolymers based on poly-ε-caprolactonc and poly(L,L or D,L)lactide by aluminum alkoxides, Macromolecules, (1991), 24(11), 3027-34.
[77] Kricheldorf H. R., Berl M., Scharnagl N., Poly(lactones) 9 Polymerization mechanism of metal alkoxide initiated polymerizations of lactide and various lactones, Macromolecules, (1988),21(2), 286-93.
[78] Dubois Ph., Ropson N., Jerome R., Teyssie Ph., Macromolecular Engineering of Polylactones and Polylactides. 19. Kinetics of Ring-Opening Polymerization of ε-Caprolactone Initiated with Functional Aluminum Alkoxides, Macromolecules 1996, 29(6), 1965.
[79] Ropson N., Dubois. Ph., Jerome R., Teyssie Ph., Macromolecular Engineering of Polylactones and Polylactides. 20. Effect of Monomer, Solvent, and Initiator on the Ring-Opening Polymerization As Initiated with Aluminum Alkoxides, Macromolecules, 1995, 28, 7589-7598.
[80] Dubois P., Ropson N., Jerome R., Teyssie P., Macromolecular engineering of polylactones and polylactides. 19.Kinetics of ring-opening polymerization of epsilon-caprolactone initiated with functional aluminum alkoxides, Macromolecules, 1996, 29 (6), 1965-1975.
[81] Ko B. T., Lin C. C., Efficient "living" and "immortal" polymerization of lactones and diblock copolymer of epsilon-CL and delta-VL catalyzed by aluminum alkoxides, Macromolecules 1999,32 (25), 8296-8300.
[82] Lewinski J., Horeglad P., Tratkiewicz E., Grzenda W., Lipkowski J., Kolodziejczyk E.,Towards the nature of active sites in polymerization of cyclic esters initiated by aluminium alkoxides: First structurally authenticated aluminium-epsilon-caprolactone complex macromolecular rapid communications 2004, 25 (23), 1939-1942
[83] Lewinski J., Horeglad P., Wojcik K., Justyniak I., Chelation effect in polymerization of cyclic esters by metal alkoxides: Structure characterization of the intermediate formed by primary insertion of lactide into the Al-OR bond of an organometallic initiator, Organometallics 2005,24 (19), 4588-4593
[84] Bradley D., Chudrynska C., H., Frigo D. M., et al. Pentanuclear oxoalkoxide cluster of scandium, yttrium, and yttbium, X-ray crystal structures of M_5(μ_5-O)(μ_3-O~iPr)_4(μ_2-O~iPr)(O~iPr)_5) (M=In, Yb), Polyhedron, 1990, 9, 719-26.
[85] Tortosa K., Hamaide T., Boisson C., et al. Homogeneous and heterogeneous polymerization of ε-caprolactone by neodymium alkoxides prepared in situ. Macromol. Chem. Phys., 2001, 202,1156-1160.
[86] Martin E., Dubois P. H., Jerome R., Preparation of supported yttrium alkoxides as catalysts for the polymerization of lactones and oxirane, Journal of Polymer Science Part A: Polymer Chemistry, 2003, 41(4), 569-578.
[87] Martin E., Dubois Ph., Jerome R., Controlled ring-opening polymerization of ε-caprolacto nepromoted by "in situ" formed yttrium Macromolecules, 2000, 33, 1530-35.
[88] Martin E., Dubois P., Jerome R., "In situ" formation of yttrium alkoxides: A versatile and efficient catalyst for the ROP of epsilon-caprolactone, Macromolecules, 2003, 36(16), 5934-5941.
[89] Yao Y. M, Xu X. P., Liu B., Zhang Y., Shen Q.. Wong, W. T., Carbon-bridged bis(phenolato)lanthaiiide alkoxides: Syntheses, structures, and their application in the controlled polymerization of epsilon-caprolactone, Inorganic chemistry, 2005,44 (14), 5133-5140.
[90] Palard I., Schappacher M., Soum A., Guillaume S. M., Ring-opening polymerization of e-caprolactone initiated by rare earth alkoxides and borohydrides: a comparative study, Polymer international, 2006, 55(10), 1132-1137.
[91] Stevels W. M, Ankone M. J. K., Dijkstra P. J., Feijen J., Kinetics and mechanism of e-caprolactone polymerization using yttrium alkoxides as initiators, Macromolecules, 1996, 29(26), 8296-303.
[92] Stevels W. M., Ankone M. J. K., Dijkstra P. J., Feijen J., Kinetics of L-lactide and e-caprolactone polymerization using a highly efficient catalyst system based on yttrium tris(2,6-di-tert-butylphenolate), Polymer Preprint, 1996,37(2), 190-191.
[93] Shen Y Q., Shen Z. Q., Zhang F. Y, Ring-opening polymerization of ε-caprolactone by rare earth alkoxide-CCl_4 systems, Polymer Journal, 1995, 27(1), 59-64.
[94] Shen Y Q., Shen Z. Q., Zhang Y. R., Novel rare earth catalysts for the living polymerization and block copolymerization of ε-caprolactone, Macromolecules, 1996, 29(26), 8289-95.
[95] Akatsuka M., Aida T., Inoue S., Alcohol/methylaluminum diphenolate systems as novel, versatile initiators for synthesis of narrow molecular weight distribution polyester and polycarbonate Macromolecules, 1995, 28(4), 1320.
[96] Stevels, W. M., Ankone M. J. K., Dijkstra P. J., Feijen J., A Versatile and Highly Efficient Catalyst System for the Preparation of Polyesters Based on Lanthanide Tris(2,6-di-tert-butylphenolate)s and Various Alcohols, Macromolecules, 1996, 29(9), 3332.
[97] Ling J., Shen Z. Q., Lanthanum tris(2,6-di-tert-butyl-4-methylphenolate) as a novel, initiator for homo- and copolymerization of cyclic carbonate and lactones, Macromol. Chem. Phys., 2002, 203, 735.
[98] Ling J., Shen Z. Q., Zhu W. P., Controlling ring-opening copolymerization of ε-caprolactone with trimethylene carbonate by scandium tris(2,6-di-tert-butyl-4-methylphenolate), Macromolecules, 2004, 37, 758-763.
[99] Fan L., Zhang L. F., Shen Z. Q., Novel single-component earth phenolate catalyst for ring-opening polymerization of e-caprolactone, Chemical Research in Chinese University, 2003. 19,516-517.
[100] Yu C. P., Zhang L. F., Shen Z. Q., Ring-opening Polymerization of ε-caprolactone using rare earth tris(4-tert-butylphenolate)s as a single component initiator, European Polymer Journal, 2003. 39, 2035-2039.
[101] Zhang L. F., Shen Z. Q., Yu C. P., Ring-opening Polymerization of ε-caprolactone by lanthanide tris(2, 6-dimethylphenolate)s, Chinese Journal of Chemistry, 2003. 21, 1236-37.
[102] Peng F, Ling J, Shen Z. Q, Zhu W. W., Correlation between Phenol Structure and Catalytic Activity of Samarium (Ⅲ) Phenolates in Polymerization of ε-Caprolactone. Part 2. Tertbutyl's Electronic and Steric Effects Journal of Molecular Catalysis A: chemical, 2005, 230, 135-141.
[103] Ling J., Chen W., Shen Z. Q.. Synthesis and characterization of poly(DTC-b-PEG-b-DTC) triblock and poIy(TMC-b-DTC-b-PEG-b-DTC-b-TMC) pentablock copolymers and kinetics of the polymerization. Journal of Polymer Science Part A: Polymer Chemistry, 2005, 43, 1787-1796.
[104] Chen W., Ling J., Shen Z. Q., Preparation and polymerization mechanism of dihydroxy-capped PCL, poly(CL-b-PEG-b-CL) and poly(DTC-b-CL-b-DTC). Sci China Ser B, 2005,48, 334-342
[105] Xie W. H., Zhu W. P., Shen Z. Q., Synthesis, isothermal crystallization and micellization of mPEG-PCL diblock copolymers catalyzed by yttrium complex, Polymer, 2007, 48(23), 6791-6798
[106] Vanka K., Chan M. S. W., Pye C. C., Ziegler T., Exploring the activation of olefin polymerization catalysts with density functional theory. Macromol Symp, 2001, 173, 163 — 177.
[107] Boero M., Parrinello M., Terakura K., Ziegler-Natta heterogeneous catalysis by first principles computer experiments, Surface Sci., 1999, 438, 1-8.
[108] Harkonen M., Seppala J. V., External silane donors in Ziegler-Natta catalysis: a two-site model simulation of the effects of various alkoxysilane compounds, Polymer, 1995, 36, 1499-1505.
[109] Ryner M., Stridsberg K., Albertsson A.-C, Mechanism of Ring-Opening Polymerization of 1,5-Dioxepan-2-one and L-Lactide with Stannous 2-Ethylhexanoate. A Theoretical Study, Macromolecules, 2001, 34, 3877-3881.
[110] Schenck H von, Ryner M, Albertsson A.-C, Svensson M, Ring-Opening Polymerization of Lactones and Lactides with Sn(IV) and Al(III) Initiators, Macromolecules, 2002, 35, 1556-1562.
[111] Ling J, Shen J. G , Hogen-Esch T E., density functional theory study of the mechanisms of scandium-alkoxide initiated coordination-insertion ring-opening polymerization of cyclic esters Polymer, 2009, 50, 3575-3581.
[112] Taylor M. D., Carter C. P., Preparation of anhydrous lanthanide halides, especially iodides Journal of Inorganic Nuclear Chemistry, 1962, 34, 387-391.
[113] Hitchcock P. B., Lappert M. F., Singh A., Tree- and four-coordinate, hydrocarbon-soluble aryloxides of scandium, yttrium, and the lanthanoids; X-ray crystal structure of tris(2,6-di-t-butyl-4-methylphenoxo) scandium, Journal of the Chemical Society, Chemical Communication, 1983, 24, 1499-1501.
[114] Gaussian 03 (Revision C.02), Frisch M. J., Trucks G.W., Schlegel H. B., Scuseria G. E., Robb M. A., Cheeseman J. R., Montgomery J. A., Vreven T., Kudin K. N., Burant J. C., Millam J. M., Iyengar S. S., Tomasi J., Barone V., Mennucci B., Cossi M., Scalmani G., Rega N., Petersson G.A., Nakatsuji H., Hada M., Ehara M., Toyota K., Fukuda R., Hasegawa J., Ishida M., Nakajima T., Honda Y., Kitao O., Nakai H., Klene M., Li X., Knox J. E., Hratchian H. P., Cross J.B., Adamo C., Jaramillo J., Gomperts R., Stratmann R. E., Yazyev O., Austin A. J., Cammi R., Pomelli C., Ochterski J. W., Ayala P. Y., Morokuma K., Voth G. A., Salvador P., Dannenbcrg J. J., Zakrzewski V. G., Dapprich S., Daniels A. D., Strain M. C., Farkas O., Malick D. K., Rabuck A. D., Raghavachari K., Foresman J. B., Ortiz J. V., Cui Q., Baboul A. G., Clifford S., Cioslowski J., Stefanov B. B., Liu G., Liashenko A., Piskorz P., Komaromi I., Martin R. L., Fox D. J., Keith T., Al-Laham M. A., Peng C. Y., Nanayakkara A., Challacombe M., Gill P. M. W., Johnson B.. Chen W., Wong M. W., Gonzalez C., Pople J.A., Gaussian, Inc, Wallingford CT, 2004.
[115] Foresman J. B., Frisch A., Exploring Chemistry with Electronic Structure Methods (Gaussian, Pittsburgh), 1995.
[116] Hitchcock P. B., Lappert M. F., Smith R. G., Tri(2,6-t-butylphenoxo)yttrium: a three-coordination hydrocarbon soluble aryloxide of yttrium, Inorganica Chimica Acta, 1987, 139, 183-184.
[117] Ling J., Shen Z. Q., Huang Q. H., Novel single rare earth aryloxide initiators for ring-opening polymerization of 2,2-dimethyltrimethylene carbonate, Macromolecules, 2001, 34, 7613-7616.
[118] Evans J. W., Shreeve J. L., Doedens R. J, Isolation and crystal structure of a six coordinate yttrium trichloride complex of .epsilon-caprolactone, YCl_3(C_6H_(10)O_2)_3, Inorganic Chemistry, 1993, 32, 245-246.
[119] Evans J. W., Shreeve J. L., Ziller J. W., Doedens R. J., Structural Diversity in Solvated Lanthanide Halide Complexes, Inorganic Chemistry, 1995, 34, 576-585.
[120] 凌君,新型稀土催化剂催化开环聚合及Monte Carlo模拟研究[博士学位论文],浙江大学,2002,47.
[121] 于翠萍,新型稀土催化剂催化生物降解高分子的合成与降解[博士学位论文],浙江大学,2004,53-54.
[122] Kricheldorf H. R., Kreiser-Saunders I., Stricker A., Polylactones 48.SnOct_2-Initiated Polymerizations of Lactide: A Mechanistic Study, Macromolecules, 2000, 33, 702-709.
[123] Cheng J., Ding J.-X., Wang Y.-C, Wang J., Synthesis and characterization of star-shaped block copolymer of poly-(s-caprolactone) and poly(ethyl ethylene phosphate) as drug carrier, Polymer, 2008,49,4784-4790.
[124] Velusamy S., Borpuzari S., Punniyamurthy T., Cobalt(Ⅱ)-catalyzed direct acetylation of alcohols with acetic acid, Tetrahedron, 2005, 61, 2011-2015.
[125] 李宗孝,崔兆科,张三敖,秦蓓,化学动力学基础,山西人民教育出版社,196-198.
[126] Laidler K. J., King M. C., The Development of Transition-State Theory, J. Phys. Chem. 1983,87,2657-2664.
[127] Ling J., Chen W., Shen Z. Q., Synthesis and characterization of poly(DTC-b-PEG-b-DTC) triblock and poly(TMC-b-DTC-b-PEG-b-DTC-b-TMC) pentablock copolymers and kinetics of the polymerization, Journal of Polymer Science Part A: Polymer Chemistry, 2005,43, 1787-1796.
[128] Barros N., Mountford P., Guillaume S. M., Maron L., A DFT Study of the Mechanism of Polymerization of ε-Caprolactone Initiated by Organolanthanide Borohydride Complexes Chemistry-A European Journal, 2008, 14, 5507-5518.
[2] Okada M., Chemical syntheses of biodegradable polymers, Progress in polymer science, 2002,27,87-133.
[3] Mochizuki M., Nakayama K., Qian R. Y, Jiang B. Z, Hirami M, Hayashi T., Masuda T.,Nakajima A., Studies on biodegradable poly(hexano-6-lactone) fibers 1. Structure and properties of drawn poly(hexano-6-lactone) fibers, Pure and applied chemistry, 1997, 69(12) 2567-2575.
[4] Shen Y. Q.; Sun W. L.; Shen Z. Q., Regulation of biodegradability and drug release behavior of aliphatic polyesters by blending. Journal of Biomedical Materials Research, 2000, 50(4), 528.
[5] Wang J. L., Wang L., Dong C.M., Synthesis, crystallization, and morphology of star-shaped poly(ε-caprolactone), Journal of Polymer Science Part A: Polymer Chemistry 2005,43(22), 5449.
[6] Feng H., Dong C.M., Preparation and characterization of chitosan-graft-poly (e-caprolactone) with an organic catalyst, Journal of Polymer Science Part A: Polymer Chemistry, 2006, 44(18),5353.
[7] Kricheldorf H. R.; Jonte J. M.; Dunsing R., Polylactones, 7 The mechanism of cationic polymerization of ε-propiolactone and ε-caprolactone, Makromolekulare Chemie, 1986, 187(4),771-785.
[8] Cherdron H., Ohse H., Korte F., The polymerization of lactones. I. Homopolymerization of 4-,6-, and 7-membered lactones with cationic initiators, Makromolekulare Chemie, 1962, 56, 179.
[9].Ludvig E. B., Beleukaya B. C. C., Mechanism of cationic polymerization of ε-caprolactone, J.Macromol. Sci. Chem, 1974, 8(4), 819.
[10] Hofman A., Slomkowski S., Penczek S., Structure of active species in the cationic polymerization of ε-propiolactone and ε-caprolactone, Makromolekulare Chemie, 1984, 185, 655.
[11] Okamoto Y., Cationic ring-opening polymerization of lactones in the presence of alcohol,Makromol. Chem. Macromol. Symp, 1991, 42, 117.
[12] Shibasaki Y., Sanda H., Yokoi M., Sanda F., Endo T., Application to well-defined block copolymer synthesis with seven-membered cyclic carbonate, Macromolecules, 2000, 33(12),4316-20.
[13] Endo T., Shibasaki Y., Sanda F., Controlled ring-opening carbonates polymerization of cyclic carbonates and lactones by an activated monomer mechanism, Journal of Polymer Science Part A:Polymer Chemistry, 2002, 13, 2190.
[14] Nomura N., Taira A., Tomioka T., A catalytic approach for cationic living polymerization:Sc(OTf)_3-catalyzed ring-opening polymerization of lactones, macromolecules, 2000, 33, 1497.
[15] Gazeau-Bureau S., Delcroix D., Martin-Vaca B., Organo-catalyzed ROP of e-caprolactone: Methanesulfonic acid competes with trifluoromethanesulfonic acid, macromolecules, 2008, 41(11),3782.
[16] Nomura N., Taira A., Nakase A,, et al.. Ring-opening polymerization of lactones by rare-earth metal triflates and by their reusable system in ionic liquids, tetrahedron, 2007, 63(35), 8478.
[17] Kim M. S., Seo K., S, Kliang G., Lee H., B., Ring-opening polymerization of epsilon-caprolactone by poly(ethylene glycol) by an activated monomer mechanism,macromolecular rapid communications, 2005, 26(8), 643.
[18] Oh J. M., Lee S. H., Son J. S., Kim M. S., Ring-opening polymerization of epsilon-caprolactone by poly(propyleneglycol) in the presence of a monomer activator, polymer,2009,50(25), 6019.
[19] Basko M., Kubisa P., Cationic copolymerization of epsilon-caprolactone and L,L-lactide by an activated monomer mechanism, Journal of Polymer Science Part A: Polymer Chemistry, 2006,44(24), 7071.
[20] Basko M., Kubisa P., Polyester oligodiols by cationic AM copolymerization of L,L-lactide and epsilon-caprolactone initiated by diols, Journal of Polymer Science Part A: Polymer Chemistry, 2007, 45(14), 3090.
[21] Gowda R. R., Chakraborty D., Environmentally benign process for bulk ring opening polymerization of lactones using iron and ruthenium chloride catalysts, journal of molecular catalysis A: chemical, 2009, 301(1-2), 84.
[22] Lofgren A., Albertsson A.-C., Dubois P., Jerome R., Recent advances in ring-opening polymerization of lactones and related compounds, Journal of Molecular Science Rev Macromolcular Chemical Physics, 1995, 35, 379.
[23] Kuhling S., Keul H., Hocker H., Copolymerization of 2,2-dimethyltrimethylene carbonate with 2-allyloxyinethyl-2-ethyltrimethylene carbonate and with ε-caprolactone using initiators on the basis of Li, Al, Zn and Sn, Makromolecular Chemistry, 1992, 193, 1207.
[24] Wurm B., Keul H., Hocker H., Dibutylmagnesium-an initiator for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate and e-Caprolactone, Makromolecular Chemical Rapid Communication 1992, 13,9.
[25] Gitsov I, Rashkov I. B, Panayotov I. M, Anionic polymerization of lactones initiated by alkali graphitides. V. Initiation mechanism and nature of the active centers, Journal of Polymer Science Part A: Polymer Chemistry, 1990, 28, 2115.
[26] Ito K., Hashizuka Y., Yamashita Y., Equilibrium Cyclic Oligomer Formation in the Anionic Polymerization of ε-Caprolactone, Macromolecules, 1977, 10, 821.
[27] Ito K., Yamashita Y., propagation and Depropagation Rates in the Anionic Polymerization of ε-Caprolactone Cyclic Oligomers, Macromolecules, 1978,11(1), 68.
[28] Stere C., Lovu M. C., Lovu H., Boborodea, A., Vasilescu DS, Read SJ, Anionic and Ionic Coordinative Polymerization of Caprolactone, Polymer Advanced Technologies, 2001, 12,300-305.
[29] Gitsov I., Rashkov I., Panayotov I. M., Golub A., Anionic polymerization of lactones initiated by alkali graphitides IV.copolymerization of ε-caprolactone initiated by KC24, Journal of Polymer Science Part A: Polymer Chemistry, 1989, 27(2), 639.
[30] Gitsov I., Ivanova P. T., Frechet J. M. J, Dendtimers as macroinitiators for anionic ring-opening polymerization of epsilon-caprolactone, macromolecular rapid communications, 1994, 15(5), 387-393.
[31] Albertsson A. C., Varnia I. K., Recent developments in ring opening polymerization of lactones for biomedical applications, Biomacromolecules, 2003,4, 1466-1486.
[32] Duda A., Kowalski A., Penczek S., Uyama H., Kobayashi S., Kinetics of the ring-opening polymerization of 6-, 7-, 9-, 12-, 13-, 16-, and 17-membered lactones. comparison of chemical and enzymatic polymerizations, Macromolecules, 2002, 35,4266-4270.
[33] Uyama H., Takeya K.., Kobayashi S., Enzymic ring-opening polymerization lactones to polyesters by lipase catalyst: unusually high reactivity of macrolides, Bull. Chem. Soc. Jpn. 1995,68,56-61.
[34] Kumar A., Gross R. A., Jendrossek D., Poly(3-hydroxybutyrate)-depolymerase from Pseudomonas lemoignei: catalysis of esterifications in organic media, Journal of Organic.Chemistry, 2000, 65,7800-7806.
[35] Ceccorulli G., Scandola M., Kumar A., Kalra, B. Gross R. A., Cocrystallization of random copolymers of ω-pentadecalactone and ε-caprolactone synthesized by lipase catalysis,Biomacromolecules, 2005, 6, 902-907.
[36] Kumar A., Kalra B., Dekhterman A., Gross R. A., Efficient ring-opening polymerization and copolymerization of ε-caprolactone and ω-pentadecalactone catalyzed by Candida antarctica lipase B, Macromolecules, 2000, 33, 6303-6309.
[37] Kumar A., Gross R. A., Candida antarctica lipase b-catalyzed transesterification: new synthetic routes to copolyesters, Journal of American Chemistry Society. 2000, 122, 11767-11770.
[38] Dong H., Wang H.-D., Cao S.-G., Shen J.-C., Lipase-catalyzed polymerization of lactones and linear hydroxyesters, Biotechnology Letter, 1998, 20, 905-908.
[39] Oishi M., Ikeo S., Nagasaki Y., Lipase-catalyzed selective synthesis and micellization of poly(ethylene glycol)-block-poly(ε-caprolactone) copolymer possessing a carboxylic acid group at the PEG chain end, Polymer Joumal(Tokyo, Japan), 2007, 39, 239-244.
[40] Duxbury C. J., Cummins D., Heise A., Selective enzymatic grafting by steric control,Macromolcular Rapid Communication, 2007, 28, 235-240.
[41] Zhou J., Wang W., Thurecht K. J., Villarroya S., Howdle S. M, Simultaneous dynamic kinetic resolution in combination with enzymatic ring-opening polymerization, Macromolecules, 2006, 39,7302-7305.
[42] Hans M., Gasteier P., Keul H., Moeller M., Ring-opening polymerization of e-caprolactone by means of mono- and multifunctional initiators: comparison of chemical and enzymatic catalysis,Macromolecules, 2006, 39, 3184-3193.
[43] Skaria S., Smet M., Frey H., Enzyme-catalyzed synthesis of hyperbranched aliphatic polyesters, Macromolcular Rapid Communication, 2002, 23, 292-296.
[44] Srivastava R.K., Albertsson A.-C., Porous scaffolds from high molecular weight polyesters synthesized via enzyme-catalyzed ring-opening polymerization, Biomacromolecules 2006, 7,2531-2538.
[45] Srivastava R. K., Albertsson A.-C., Enzyme-catalyzed ring-opening polymerization of seven-membered ring lactones leading to terminalfunctionalized and triblock polyesters,Macromolecules, 2006, 39,46-54.
[46] Srivastava R. K., Kumar K., Varma I. K., Albertsson A.-C., Chemoenzymatic synthesis of comb polymers, European Polymer Jounal, 2007,43, 808-817.
[47] Albertsson A.-C., Srivastava R. K., Recent developments in enzyme-catalyzed ring-opening polymerization, Advanced Drug Delivery Reviews, 2008, 60, 1077-1093
[48] Kricheldorf H. R, Sumbel M. V., Kreiser-Saunders I., Polylactones20.Polymerization of epsilon-caprolactone with tributylin derivatives: a mechanistic study, Macromolecules 1991, 24(8),1944.
[49.] Shen Y. Q., Shen Z. Q., Shen J. L., Zhang Y. F, Yao K. M., Characteristics and Mechanism of ε-Caprolactone Polymerization with Rare Earth Halide Systems, Macromolecules, 1996, 29, 3441.
[50] Shen Y. Q., Shen Z. Q., Shen J. L., Zhang Y. F., Huang Q. H., A comparison of mechanisms of ε-caprolactone and trimethylene carbonate with rare earth halides, Journal of Polymer Science Part A: Polymer Chemistry, 1997, 35, 1339-1352.
[51] Shen Y. Q., Huang Q. H., Shen Z. Q., Ramdom copolymerization of lactone and trimethylene carbonate with rare earth catalysts. Journal of Applied Polymer Science, 1997, 64, 2131-39.
[52] Ogawa A., Takami N., Sekiguchi M., Ryu I., Kambe N., Sonodo N., The first deoxygenative coupling of amides by an unprecedented samarium/samarium diiodide system, Journal of the American Chemical Society, 1992, 114, 8729-8730.
[53] Agarwal S., Brandukova-Szmikowski N. E., Greiner A., Reactivity of Sm(II) compounds as ring-opening polymerization initiators for lactones, Macromolecular Rapid Communication, 1999,20, 274-78.
[54] Agarwal S., Naumann N., Xie X. L., Synthesis and microstructural characterization of ethylene carbonate-ε-cprolactoneL-lactide copolymers using one- and two-dimensional NMR spectroscopy, Macromolecules, 2002, 35, 7713-7717.
[55] Agarwal S., Xie X. L., SmI_2/Sm-based γ-butyrolactone-ε-caprolactone copolymers:microstructural characterization using one- and two-dimensional NMR spectroscopy,Macromolecules, 2003, 36, 3545-3549.
[56] Gattin R., Cretu A., Denise B.-B., effect of the remaining lanthanide catalysts on the hydrolytic and enzymatic degradation of poly(ε-caprolactone), Macromol. Symp.2003, 197,455-466.
[57] Scott N. M., Schareina T., Tok O., Kempe R., Lithium and Potassium Amides of Sterically Demanding Aminopyridines, European Journal Inorganic Chemistry, 2004, 3297-3304.
[58] Scott N. M., Kempe R., Di- and Trivalent Lanthanide Complexes Stabilized by Sterically Demanding Aminopyridinato Ligands, European Journal Inorganic Chemistry, 2005, 1319-1324.
[59] Guillaume S. M., Schappacher M., Scott N. M., Kempe R., Di- and trivalent rare earth complexes stabilized by sterically demanding aminopyridinato ligands as initiators in ring-opening polymerization reactions of epsilon-caprolactone, Journal of Polymer Science Part A: Polymer Chemistry, 2007,45(16), 3611-3619.
[60] Deng X. M., Yuan M. L., Xiong C. D., Polymerization of lactide and lactones. Ring-opening polymerization of ε-caprolaetone and DL-lactide by organoacid compounds. Journal of Applied Polymer Science, 1999,71, 1941-1948.
[61] Zhang J., Gan Z. H., Zhong Z. Y, et al A novel rare earth coordination catalyst for polymerization of biodegradable aliphatic lactones and lactides, Polymer International, 1998, 45,60-66.
[62] Zhong Z. Y., Yu D. H., Meng F. H., et al. Controlled synthesis of L-lactide-b-ε-caprolactone block copolymers using a rare earth complex as catalyst. Polymer, Journal, 1999, 31, 633-636.
[63] Shen Z. Q., Chen X. H., Shen Y Q., et al. Ring-opening polymerization of ε-caprolactone by rare earth coordination catalysts. I. Characteristics, kinetics, and mechanism of ε-caprolactone polymerization with Nd(acac)_3 3H_2O-AlEt_3 system. Journal of Polymer Science Part A: Polymer Chemistry, 1994,32, 597-603.
[64] Kowalski A., Duda A., Penczek S., Mechanism of Cyclic Ester Polymerisation Initiated with Tin(II) Octoate 2. Macromolecules Fitted with Tin Alkoxide Species Observed Directly in MALDI-TOF Spectra, Macromolecules, 2000, 33(3), 689-695.
[65] Storey R. F., Sherman J. W., Kinetics and Mechanism of the Stannous Octoate-Catalyzed Bulk Polymerisation of ￡-Caprolactone, Macromolecules 2002, 35(5), 1504-1512.
[66] Kricheldorf H. R, Kreiser-Saunders I, Boettcher C, Polylactones: 31. Sn(II)octoate-initiated polymerization of L-lactide: a mechanistic study, Polymer, 1995, 36, 1253.
[67] Stjerndahl A., Finne-Wistrand A, Albertsson A.-C.,. Backesjo, C. M., Lindgren, U.,Minimization of residual tin in the controlled Sn(II)octoate-catalyzed polymerization of epsilon-caprolactone, Journal of biomedical materials research part A, 2008, 87, 1086-1091.
[68] Kowalski, A., Duda, A., Penczek, S., Kinetics and Mechanism of Cyclic Esters Polymerization Initiated with Tin(II) Octoate. 3. Polymerization of L, L-Dilactide Macromolecules, 2000, 33, 7359-7370.
[69] Kowalski A., Duba A., Libiszowski J., Penczek S., Kinetics and mechanism of cyclic esters polymerization initiated with Tin(II) octoate, Polymerization of caprolactone and L-lactide co-initiated with primary amines, Macromolecules, 2005, 38(21), 8170-6.
[70] Kowalski A., Libiszowski J., Majerska K., Duda A., Penczek S., Kinetics and mechanism of ￡-caprolactone and L,L-lactide polymerization coinitiated with zinc octoate or aluminum acetylacetonate: The next proofs for the general alkoxide mechanism and synthetic applications,Polymer, 2007, 48(14), 3952-3960.
[71] Wu R. Z., Al-Azemi T. F; Bisht K. S., One-Shot Block Copolymcrization of a Functional Seven-Membered Cyclic Carbonate Derived from L-Tartaric Acid with epsilon-Caprolactone,macromolecules, 2009, 42(7), 2401-2410.
[72] Jia Y. T., Shen X. Y., Gu X. H., Dong J., Mu C. X., Zhang, Y. Q., Synthesis and characterization of tercopolymers derived from epsilon-caprolactone, trimethylene carbonate,and lactide, polymer for advanced technologies, 2008, 19 (2), 159-166.
[73] Cheng J., Ding J. X., Wang Y. C., Wang J, Synthesis and characterization of star-shaped block copolymer of poly(epsilon-caprolactone) and poly(ethylethylene phosphate) as drug carrier,polymer, 2008, 49 (22), 4784-4790.
[74] Mahmud A., Xiong X. B., Lavasanifar A., Novel self-associating poly(ethylene oxide)-block-poly(epsilon-caprolactone) block copolymers with functional side groups on the polyester block for drug delivery, macromolecules, 2006, 39 (26), 9419-9428.
[75] He B., Chan-Park M. B., Synthesis and characterization of functionalizable and photopatternable poly(epsilon-caprolactone-co-RS-betamalicacid), macromolecules, 2005, 38 (20),8227-8234.
[76] Jacobs C., Dubois R., Jerome R., et al, Macromolecular engineering of polylactones and polylactides.5.Synthesis and characterization of diblock copolymers based on poly-ε-caprolactonc and poly(L,L or D,L)lactide by aluminum alkoxides, Macromolecules, (1991), 24(11), 3027-34.
[77] Kricheldorf H. R., Berl M., Scharnagl N., Poly(lactones) 9 Polymerization mechanism of metal alkoxide initiated polymerizations of lactide and various lactones, Macromolecules, (1988),21(2), 286-93.
[78] Dubois Ph., Ropson N., Jerome R., Teyssie Ph., Macromolecular Engineering of Polylactones and Polylactides. 19. Kinetics of Ring-Opening Polymerization of ε-Caprolactone Initiated with Functional Aluminum Alkoxides, Macromolecules 1996, 29(6), 1965.
[79] Ropson N., Dubois. Ph., Jerome R., Teyssie Ph., Macromolecular Engineering of Polylactones and Polylactides. 20. Effect of Monomer, Solvent, and Initiator on the Ring-Opening Polymerization As Initiated with Aluminum Alkoxides, Macromolecules, 1995, 28, 7589-7598.
[80] Dubois P., Ropson N., Jerome R., Teyssie P., Macromolecular engineering of polylactones and polylactides. 19.Kinetics of ring-opening polymerization of epsilon-caprolactone initiated with functional aluminum alkoxides, Macromolecules, 1996, 29 (6), 1965-1975.
[81] Ko B. T., Lin C. C., Efficient "living" and "immortal" polymerization of lactones and diblock copolymer of epsilon-CL and delta-VL catalyzed by aluminum alkoxides, Macromolecules 1999,32 (25), 8296-8300.
[82] Lewinski J., Horeglad P., Tratkiewicz E., Grzenda W., Lipkowski J., Kolodziejczyk E.,Towards the nature of active sites in polymerization of cyclic esters initiated by aluminium alkoxides: First structurally authenticated aluminium-epsilon-caprolactone complex macromolecular rapid communications 2004, 25 (23), 1939-1942
[83] Lewinski J., Horeglad P., Wojcik K., Justyniak I., Chelation effect in polymerization of cyclic esters by metal alkoxides: Structure characterization of the intermediate formed by primary insertion of lactide into the Al-OR bond of an organometallic initiator, Organometallics 2005,24 (19), 4588-4593
[84] Bradley D., Chudrynska C., H., Frigo D. M., et al. Pentanuclear oxoalkoxide cluster of scandium, yttrium, and yttbium, X-ray crystal structures of M_5(μ_5-O)(μ_3-O~iPr)_4(μ_2-O~iPr)(O~iPr)_5) (M=In, Yb), Polyhedron, 1990, 9, 719-26.
[85] Tortosa K., Hamaide T., Boisson C., et al. Homogeneous and heterogeneous polymerization of ε-caprolactone by neodymium alkoxides prepared in situ. Macromol. Chem. Phys., 2001, 202,1156-1160.
[86] Martin E., Dubois P. H., Jerome R., Preparation of supported yttrium alkoxides as catalysts for the polymerization of lactones and oxirane, Journal of Polymer Science Part A: Polymer Chemistry, 2003, 41(4), 569-578.
[87] Martin E., Dubois Ph., Jerome R., Controlled ring-opening polymerization of ε-caprolacto nepromoted by "in situ" formed yttrium Macromolecules, 2000, 33, 1530-35.
[88] Martin E., Dubois P., Jerome R., "In situ" formation of yttrium alkoxides: A versatile and efficient catalyst for the ROP of epsilon-caprolactone, Macromolecules, 2003, 36(16), 5934-5941.
[89] Yao Y. M, Xu X. P., Liu B., Zhang Y., Shen Q.. Wong, W. T., Carbon-bridged bis(phenolato)lanthaiiide alkoxides: Syntheses, structures, and their application in the controlled polymerization of epsilon-caprolactone, Inorganic chemistry, 2005,44 (14), 5133-5140.
[90] Palard I., Schappacher M., Soum A., Guillaume S. M., Ring-opening polymerization of e-caprolactone initiated by rare earth alkoxides and borohydrides: a comparative study, Polymer international, 2006, 55(10), 1132-1137.
[91] Stevels W. M, Ankone M. J. K., Dijkstra P. J., Feijen J., Kinetics and mechanism of e-caprolactone polymerization using yttrium alkoxides as initiators, Macromolecules, 1996, 29(26), 8296-303.
[92] Stevels W. M., Ankone M. J. K., Dijkstra P. J., Feijen J., Kinetics of L-lactide and e-caprolactone polymerization using a highly efficient catalyst system based on yttrium tris(2,6-di-tert-butylphenolate), Polymer Preprint, 1996,37(2), 190-191.
[93] Shen Y Q., Shen Z. Q., Zhang F. Y, Ring-opening polymerization of ε-caprolactone by rare earth alkoxide-CCl_4 systems, Polymer Journal, 1995, 27(1), 59-64.
[94] Shen Y Q., Shen Z. Q., Zhang Y. R., Novel rare earth catalysts for the living polymerization and block copolymerization of ε-caprolactone, Macromolecules, 1996, 29(26), 8289-95.
[95] Akatsuka M., Aida T., Inoue S., Alcohol/methylaluminum diphenolate systems as novel, versatile initiators for synthesis of narrow molecular weight distribution polyester and polycarbonate Macromolecules, 1995, 28(4), 1320.
[96] Stevels, W. M., Ankone M. J. K., Dijkstra P. J., Feijen J., A Versatile and Highly Efficient Catalyst System for the Preparation of Polyesters Based on Lanthanide Tris(2,6-di-tert-butylphenolate)s and Various Alcohols, Macromolecules, 1996, 29(9), 3332.
[97] Ling J., Shen Z. Q., Lanthanum tris(2,6-di-tert-butyl-4-methylphenolate) as a novel, initiator for homo- and copolymerization of cyclic carbonate and lactones, Macromol. Chem. Phys., 2002, 203, 735.
[98] Ling J., Shen Z. Q., Zhu W. P., Controlling ring-opening copolymerization of ε-caprolactone with trimethylene carbonate by scandium tris(2,6-di-tert-butyl-4-methylphenolate), Macromolecules, 2004, 37, 758-763.
[99] Fan L., Zhang L. F., Shen Z. Q., Novel single-component earth phenolate catalyst for ring-opening polymerization of e-caprolactone, Chemical Research in Chinese University, 2003. 19,516-517.
[100] Yu C. P., Zhang L. F., Shen Z. Q., Ring-opening Polymerization of ε-caprolactone using rare earth tris(4-tert-butylphenolate)s as a single component initiator, European Polymer Journal, 2003. 39, 2035-2039.
[101] Zhang L. F., Shen Z. Q., Yu C. P., Ring-opening Polymerization of ε-caprolactone by lanthanide tris(2, 6-dimethylphenolate)s, Chinese Journal of Chemistry, 2003. 21, 1236-37.
[102] Peng F, Ling J, Shen Z. Q, Zhu W. W., Correlation between Phenol Structure and Catalytic Activity of Samarium (Ⅲ) Phenolates in Polymerization of ε-Caprolactone. Part 2. Tertbutyl's Electronic and Steric Effects Journal of Molecular Catalysis A: chemical, 2005, 230, 135-141.
[103] Ling J., Chen W., Shen Z. Q.. Synthesis and characterization of poly(DTC-b-PEG-b-DTC) triblock and poIy(TMC-b-DTC-b-PEG-b-DTC-b-TMC) pentablock copolymers and kinetics of the polymerization. Journal of Polymer Science Part A: Polymer Chemistry, 2005, 43, 1787-1796.
[104] Chen W., Ling J., Shen Z. Q., Preparation and polymerization mechanism of dihydroxy-capped PCL, poly(CL-b-PEG-b-CL) and poly(DTC-b-CL-b-DTC). Sci China Ser B, 2005,48, 334-342
[105] Xie W. H., Zhu W. P., Shen Z. Q., Synthesis, isothermal crystallization and micellization of mPEG-PCL diblock copolymers catalyzed by yttrium complex, Polymer, 2007, 48(23), 6791-6798
[106] Vanka K., Chan M. S. W., Pye C. C., Ziegler T., Exploring the activation of olefin polymerization catalysts with density functional theory. Macromol Symp, 2001, 173, 163 — 177.
[107] Boero M., Parrinello M., Terakura K., Ziegler-Natta heterogeneous catalysis by first principles computer experiments, Surface Sci., 1999, 438, 1-8.
[108] Harkonen M., Seppala J. V., External silane donors in Ziegler-Natta catalysis: a two-site model simulation of the effects of various alkoxysilane compounds, Polymer, 1995, 36, 1499-1505.
[109] Ryner M., Stridsberg K., Albertsson A.-C, Mechanism of Ring-Opening Polymerization of 1,5-Dioxepan-2-one and L-Lactide with Stannous 2-Ethylhexanoate. A Theoretical Study, Macromolecules, 2001, 34, 3877-3881.
[110] Schenck H von, Ryner M, Albertsson A.-C, Svensson M, Ring-Opening Polymerization of Lactones and Lactides with Sn(IV) and Al(III) Initiators, Macromolecules, 2002, 35, 1556-1562.
[111] Ling J, Shen J. G , Hogen-Esch T E., density functional theory study of the mechanisms of scandium-alkoxide initiated coordination-insertion ring-opening polymerization of cyclic esters Polymer, 2009, 50, 3575-3581.
[112] Taylor M. D., Carter C. P., Preparation of anhydrous lanthanide halides, especially iodides Journal of Inorganic Nuclear Chemistry, 1962, 34, 387-391.
[113] Hitchcock P. B., Lappert M. F., Singh A., Tree- and four-coordinate, hydrocarbon-soluble aryloxides of scandium, yttrium, and the lanthanoids; X-ray crystal structure of tris(2,6-di-t-butyl-4-methylphenoxo) scandium, Journal of the Chemical Society, Chemical Communication, 1983, 24, 1499-1501.
[114] Gaussian 03 (Revision C.02), Frisch M. J., Trucks G.W., Schlegel H. B., Scuseria G. E., Robb M. A., Cheeseman J. R., Montgomery J. A., Vreven T., Kudin K. N., Burant J. C., Millam J. M., Iyengar S. S., Tomasi J., Barone V., Mennucci B., Cossi M., Scalmani G., Rega N., Petersson G.A., Nakatsuji H., Hada M., Ehara M., Toyota K., Fukuda R., Hasegawa J., Ishida M., Nakajima T., Honda Y., Kitao O., Nakai H., Klene M., Li X., Knox J. E., Hratchian H. P., Cross J.B., Adamo C., Jaramillo J., Gomperts R., Stratmann R. E., Yazyev O., Austin A. J., Cammi R., Pomelli C., Ochterski J. W., Ayala P. Y., Morokuma K., Voth G. A., Salvador P., Dannenbcrg J. J., Zakrzewski V. G., Dapprich S., Daniels A. D., Strain M. C., Farkas O., Malick D. K., Rabuck A. D., Raghavachari K., Foresman J. B., Ortiz J. V., Cui Q., Baboul A. G., Clifford S., Cioslowski J., Stefanov B. B., Liu G., Liashenko A., Piskorz P., Komaromi I., Martin R. L., Fox D. J., Keith T., Al-Laham M. A., Peng C. Y., Nanayakkara A., Challacombe M., Gill P. M. W., Johnson B.. Chen W., Wong M. W., Gonzalez C., Pople J.A., Gaussian, Inc, Wallingford CT, 2004.
[115] Foresman J. B., Frisch A., Exploring Chemistry with Electronic Structure Methods (Gaussian, Pittsburgh), 1995.
[116] Hitchcock P. B., Lappert M. F., Smith R. G., Tri(2,6-t-butylphenoxo)yttrium: a three-coordination hydrocarbon soluble aryloxide of yttrium, Inorganica Chimica Acta, 1987, 139, 183-184.
[117] Ling J., Shen Z. Q., Huang Q. H., Novel single rare earth aryloxide initiators for ring-opening polymerization of 2,2-dimethyltrimethylene carbonate, Macromolecules, 2001, 34, 7613-7616.
[118] Evans J. W., Shreeve J. L., Doedens R. J, Isolation and crystal structure of a six coordinate yttrium trichloride complex of .epsilon-caprolactone, YCl_3(C_6H_(10)O_2)_3, Inorganic Chemistry, 1993, 32, 245-246.
[119] Evans J. W., Shreeve J. L., Ziller J. W., Doedens R. J., Structural Diversity in Solvated Lanthanide Halide Complexes, Inorganic Chemistry, 1995, 34, 576-585.
[120] 凌君,新型稀土催化剂催化开环聚合及Monte Carlo模拟研究[博士学位论文],浙江大学,2002,47.
[121] 于翠萍,新型稀土催化剂催化生物降解高分子的合成与降解[博士学位论文],浙江大学,2004,53-54.
[122] Kricheldorf H. R., Kreiser-Saunders I., Stricker A., Polylactones 48.SnOct_2-Initiated Polymerizations of Lactide: A Mechanistic Study, Macromolecules, 2000, 33, 702-709.
[123] Cheng J., Ding J.-X., Wang Y.-C, Wang J., Synthesis and characterization of star-shaped block copolymer of poly-(s-caprolactone) and poly(ethyl ethylene phosphate) as drug carrier, Polymer, 2008,49,4784-4790.
[124] Velusamy S., Borpuzari S., Punniyamurthy T., Cobalt(Ⅱ)-catalyzed direct acetylation of alcohols with acetic acid, Tetrahedron, 2005, 61, 2011-2015.
[125] 李宗孝,崔兆科,张三敖,秦蓓,化学动力学基础,山西人民教育出版社,196-198.
[126] Laidler K. J., King M. C., The Development of Transition-State Theory, J. Phys. Chem. 1983,87,2657-2664.
[127] Ling J., Chen W., Shen Z. Q., Synthesis and characterization of poly(DTC-b-PEG-b-DTC) triblock and poly(TMC-b-DTC-b-PEG-b-DTC-b-TMC) pentablock copolymers and kinetics of the polymerization, Journal of Polymer Science Part A: Polymer Chemistry, 2005,43, 1787-1796.
[128] Barros N., Mountford P., Guillaume S. M., Maron L., A DFT Study of the Mechanism of Polymerization of ε-Caprolactone Initiated by Organolanthanide Borohydride Complexes Chemistry-A European Journal, 2008, 14, 5507-5518.