Hydrocarbon complexes of ruthenium. Part I. Formation of 1,2,3,3a,6a-η-1,4,5,6-tetrahydropentalenyl complexes from organo-silyl- and -germyl-(carbonyl)ruthenium compounds

Abstract

all-trans-Cyclododeca-1,5,9-triene undergoes a ring contraction reaction with tetracarbonylbis(trimethylgermyl)ruthenium to give the tetrahydropentalenylruthenium complexes [Ru(GeMe₃)(CO)₂(C₈H₉)] and [Ru₂(GeMe₃)(µ-GeMe₂)₂(CO)₄C₈H₉], and the pentalene complex [Ru₂(GeMe₃)₂(CO)₄(C₈H₆)]. The two tetrahydropentalenyl complexes are also formed in the reaction between cyclo-octa-1,5-diene and tetracarbonylbis(trimethylgermyl)ruthenium, but the major product of this reaction is the cyclo-octa-1,5-diene complex [Ru(GeMe₃)₂(CO)₂(C₈H₁₂)]. Cyclododeca-1,5,9-triene also undergoes ring contraction on reaction with Ru(SiMe₃)₂(CO)₄, forming [Ru(SiMe₃)(CO)₂(C₈H₉)] and [Ru₂(CO)₆(C₈H₁₀)]. Similar reactions occur with the binuclear ruthenium compounds [Ru(CO)₄(MMe₃)]₂(M = Si or Ge).