Conditioned P-CH2 Bond Cleavage of a -DPPM Ligand in a Cationic Diruthenium System
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- 作者：Kom-Bei Shiu ; Shih-Wei Jean ; Hsiang-Jen Wang ; Sue-Lein Wang ; Fen-Ling Liao ; Ju-Chun Wang ; and Lin-Shu Liou
- 刊名：Organometallics
- 出版年：1997
- 出版时间：January 7, 1997
- 年：1997
- 卷：16
- 期：1
- 页码：114 - 119
- 全文大小：229K
- 年卷期：v.16,no.1(January 7, 1997)
- ISSN：1520-6041
文摘
Thermal reactions of[Ru2(CO)4(
-O2CMe)(-DPPM)2]+([1]+) with an excess amount ofneutral two-electron nucleophiles in MeCN have been studied. TheP-CH2 bond of onecoordinated DPPM ligand can be cleaved, depending on the choice of thenucleophiles used.Reactions of [1]+ with MeCN andphosphite P(OMe)3 afford only substitutedproducts[Ru2(CO)2L2(-O2CMe)(-DPPM)2]+(L = MeCN ([2a]+), P(OMe)3([2b]+)) via intermediates[Ru2(CO)3L(-O2CMe)(-DPPM)2]+(L = MeCN ([3a]+), P(OMe)3([3b]+)). Compounds[2a]+and [3a]+ can be prepared alternatively fromdecarbonylation reaction of [1]+ with asuitableamount of Me3NO in MeCN at ambient temperature, andthe structure of [3a][BPh4]hasbeen determined by X-ray diffraction. Reactions of[1]+ with phosphines (PR3)PPh3, PPh2Me, and PEt3, however, yield unexpected products,[Ru2(CO)2(PR3)2(-O2CMe)(-DPPM)(-PPh2)] (4) and[Ph2PCH2PR3][BPh4](5). The triphenylphosphine products, 4a and[5a]+,can be prepared alternatively from the thermal reaction of either[2a]+ or [3a]+with excessPPh3. Reaction of [1]+ witha stoichiometric amount of PPh3 helped to reveal thepresenceof a cationic intermediate[Ru2(CO)2(PR3)(1,
2-CH2PPh2)(-O2CMe)(-DPPM)(-PPh2)]+([6]+),produced apparently from[Ru2(CO)3(PR3)(-O2CMe)(-DPPM)2]+([3c]+). An electronicsupersaturation rather than a transient unsaturation is proposed toaccount for the observedP-CH2 bond cleavage taking place for[3c]+. Both the spectroscopic and theX-ray structuralresults of the triphenylphospine intermediate[6a][BPh4] indicate the presence of twoisomericforms in an approximate ratio of 1:5, differing probably in therelative orientation of theCH2PPh2 group with respect to thecarboxylato bridge.
-O2CMe)(-DPPM)2]+([1]+) with an excess amount ofneutral two-electron nucleophiles in MeCN have been studied. TheP-CH2 bond of onecoordinated DPPM ligand can be cleaved, depending on the choice of thenucleophiles used.Reactions of [1]+ with MeCN andphosphite P(OMe)3 afford only substitutedproducts[Ru2(CO)2L2(-O2CMe)(-DPPM)2]+(L = MeCN ([2a]+), P(OMe)3([2b]+)) via intermediates[Ru2(CO)3L(-O2CMe)(-DPPM)2]+(L = MeCN ([3a]+), P(OMe)3([3b]+)). Compounds[2a]+and [3a]+ can be prepared alternatively fromdecarbonylation reaction of [1]+ with asuitableamount of Me3NO in MeCN at ambient temperature, andthe structure of [3a][BPh4]hasbeen determined by X-ray diffraction. Reactions of[1]+ with phosphines (PR3)PPh3, PPh2Me, and PEt3, however, yield unexpected products,[Ru2(CO)2(PR3)2(-O2CMe)(-DPPM)(-PPh2)] (4) and[Ph2PCH2PR3][BPh4](5). The triphenylphosphine products, 4a and[5a]+,can be prepared alternatively from the thermal reaction of either[2a]+ or [3a]+with excessPPh3. Reaction of [1]+ witha stoichiometric amount of PPh3 helped to reveal thepresenceof a cationic intermediate[Ru2(CO)2(PR3)(1,2-CH2PPh2)(-O2CMe)(-DPPM)(-PPh2)]+([6]+),produced apparently from[Ru2(CO)3(PR3)(-O2CMe)(-DPPM)2]+([3c]+). An electronicsupersaturation rather than a transient unsaturation is proposed toaccount for the observedP-CH2 bond cleavage taking place for[3c]+. Both the spectroscopic and theX-ray structuralresults of the triphenylphospine intermediate[6a][BPh4] indicate the presence of twoisomericforms in an approximate ratio of 1:5, differing probably in therelative orientation of theCH2PPh2 group with respect to thecarboxylato bridge.© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号 地址：北京市海淀区学院路29号 邮编：100083 电话：办公室：(+86 10)66554848；文献借阅、咨询服务、科技查新：66554700 |