Thiocyanogen Insertion into P-C Bonds of Diphosphinomethanide Complexes, Leading to Rare Functionalized Diphosphine and Tetraphosphine Ligands
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- 作者：Javier Ruiz ; Roberto Quesada ; Marilí ; n Vivanco ; Santiago Garcí ; a-Granda ; M. Rosario Dí ; az
- 刊名：Organometallics
- 出版年：2007
- 出版时间：March 26, 2007
- 年：2007
- 卷：26
- 期：7
- 页码：1703 - 1711
- 全文大小：202K
- 年卷期：v.26,no.7(March 26, 2007)
- ISSN：1520-6041
文摘
The complex fac-[Mn(CNtBu)(CO)3{(PPh2)2C-SCN}] (2) reacts with thiocyanogen, affording theunstable derivative fac-[Mn(CNtBu)(CO)3{(PPh2)C(SCN)C(SSCN)N(PPh2)}] (3), as a result of the insertionof the pseudohalogen molecule into one of the P-C bonds of the diphosphinomethanide ligand. Thiscomplex undergoes intermolecular sulfur-sulfur coupling processes, with elimination of the pseudohalogenmolecules (SCN)2, S(CN)2, and (CN)2, to yield a mixture of the dinuclear complexes fac-[{Mn(CNtBu)(CO)3(PPh2)C(SCN)C(NPPh2)}2-Sn] (4-6) linked through polysulfide chains of different lengths.Treatment of these dinuclear disulfide and trisulfide derivatives with 1 or 2 equiv of HBF4 resulted inthe sequential protonation of the nitrogen atoms of the ligand, yielding cationic and dicationic complexes,respectively. In the case of monoprotonated disulfide derivatives 31P NMR experiments reveal the existenceof an intramolecular proton-transfer process between the endocyclic nitrogen atoms of both metallicfragments. Similar insertion reactions are observed in the treatment of other diphosphinomethanidecomplexes containing a P2C-S skeleton such as fac-[Mn(L)(CO)3{(PPh2)2C-SC(S)NMe2}] (11a, L =CNtBu; 11b, L = CO) and fac-[Mn(CNtBu)(CO)3{(PPh2)2C-S(C5NH3NO2)}] (12) with thiocyanogen,yielding new mononuclear derivatives, whose formation implies additionally unusual transposition andcyclization processes. These mononuclear complexes can be protonated on the nitrogen atom by additionof HBF4, affording complexes containing rare functionalized diphosphine ligands.