Synthesis and reactions of the carbene complexes [M(SnPh3)(CO)2{C(OEt)Ph}L](M = Mo or W; L =η-C5H5,η-C5Me5 or indenyl), [M(SnPh3)(CO)2{C(OEt)Me}(η-C5H5)](M = Mo or W) and [MI(CO)2{C(OEt)R}(η-C5H5)](M = Mo or W, R = Me or Ph). X-Ray crystal structures of [Mo(SnPh3)(CO)2{C(OEt)Ph}(η-C5Me5)] and [WI(CO)2{C(OEt)Ph}(η-C5H5)]

Abstract

Treatment of the tricarbonyls [M(SnPh₃)(CO)₃L][M = Mo or W; L =η-C₅H₅, η-C₅Me₅ or η⁵-C₉H₇-(indenyl)] with LiPh followed by [OEt₃][BF₄] results in the formation of the carbenes [M(SnPh₃)(CO)₂{C(OEt)Ph}L] in good to high yields. Related reactions of [M(SnPh₃)(CO)₃(η-C₅H₅)] but using LiMe afford [M(SnPh₃)(CO)₂{C(OEt)Me}(η-C₅H₅)]. The complex trans-[M(SnPh₃)(CO)₂{C(OEt)Ph}(η-C₅Me₅)] is monoclinic, a, = 14.611(36), b= 16.788(20), c= 16.183(30)Å, β= 96.08(18)°, and R= 0.0888 for 2117 independent reflections. While the η-C₅H₅ and indenyl complexes exist as pairs of isomers in solution generated by rotation about the MC_carbene bond, the η-C₅Me₅ complexes exist as single isomers in solution. Treatment of [M(SnPh₃)(CO)₂{C(OEt)Ph}(η-C₅H₅)](M = Mo or W) with I₂ results in formation of the iodometal species [MI(CO)₂{C(OEt)Ph}(η-C₅H₅)]. The complex [WI(CO)₂{C(OEt)Ph}(η-C₅H₅)] is monoclinic, a= 9.34(3), b= 13.00(2), c= 13.53(3)Å, β= 97.8(2)°, and R= 0.0812 for 2091 independent reflections. In solution this compound exists as the three trans isomers and one cis. Treatment of [M(SnPh₃)(CO)₂{C(OEt)Ph}(η-C₅Me₅)] with I₂ results in the eventual formation of [MoPh(CO)₃(η-C₅Me₅)] in the molybdenum case and [MI₃(CO)₂(η-C₅Me₅)] in both cases.