Synthesis and structures of bimetallic silicon-containing imido alkylidene complexes of tungsten (R′O)2(ArN)WCH–SiR2–CHW(NAr)(OR′)2 (R = Me, Ph) and (R′O)2(ArN)WCH–SiMe2SiMe2–CHW(NAr)(OR′)2

Bimetallic alkylidene complexes of tungsten (R′O)2(ArN)WCH–SiR2–CHW(NAr)(OR′)2 (R = Me (1), Ph (2)) and (R′O)2(ArN)WCH–SiMe2SiMe2–CHW(NAr)(OR′)2 (3) (Ar = 2,6–Pr2iC6H3; R′ = CMe2CF3) have been prepared by the reactions of divinyl silicon reagents R2Si(CHCH2)2 with known alkylidene compounds R′′–CHMo(NAr)(OR′)2. (R′′ = But, PhMe2C) Complexes 1–3 were structurally characterized. Ring opening metathesis polymerization (ROMP) of cyclooctene using compounds 1–3 as initiators led to the formation of high molecular weight polyoctenamers with predominant trans-units content in the case of 1 and 3 and predominant cis-units content in the case of 2.

Graphical abstractBimetallic alkylidene complexes of tungsten (R′O)2(ArN)WCH–SiR2–CHW(NAr)(OR′)2 (R = Me (1), Ph (2)) and (R′O)2(ArN)WCH–SiMe2SiMe2–CHW(NAr)(OR′)2 (3) (Ar = 2,6–Pr2iC6H3; R′ = CMe2CF3) have been synthesized and structurally characterized. Compounds 1–3 were found to be active initiators for ROMP of cyclooctene and led to the formation of high molecular weight polyoctenamers with predominant trans-units content in the case of 1 and 3 and predominant cis-units content in the case of 2.Figure optionsDownload full-size imageDownload as PowerPoint slide