Bis-mixed-carbene ruthenium-thiolate-alkylidene complexes: synthesis and olefin metathesis activity

Abstract

A series of bis-carbene Ru-hydride species, including (IMes)(Im(OMe)₂)(PPh₃)RuHCl (1) and (SIMes)(Me₂Im(OMe)₂)(PPh₃)RuHCl (2) were prepared and subsequently shown to react with aryl-vinyl-sulfides to give the bis-carbene-alkylidene complexes: Im(OMe)₂(SIMes)RuCl(SR)(CHCH₃) (R = p-FC₆H₄ (3), p-(NO₂)C₆H₄ (4)), Im(OMe)₂(IMes)RuCl(CHCH₃)(SPh) (5), Me₂Im(OMe)₂(SIMes)RuCl(CHCH₃)(SPh) (6), Im(OMe)₂(SIMes)(F₅C₆S)RuCl(CHR) (R = C₄H₉ (9), C₅H₁₁ (10)). The activity of these species in the standard Grubbs’ tests for ring-opening metathesis polymerization, ring-closing and cross-metathesis are reported. Although these thiolate derivatives are shown to exhibit modest metathesis activities, the reactivity is enhanced in the presence of BCl₃.