Ring-methyl activation in pentamethylcyclopentadienyl complexes. 4. Syntheses, structures, and reactions of [(C5Me4CH2Cl)RuCl(CO)2] and related compounds: X-ray structures of [(C5Me4CH2Cl)RuCl(CO)2] and [(C5Me4CH2OEt)Ru(PPh3)(CO) 2](OTf)

Article abstract of DOI:10.1021/om00002a015

The dicarbonyl chloro complex [(C₅Me₄CH₂Cl)RuCl(CO)₂] (4) is formed by carbonylation (1 atm, 20°C 5 min) of the dimeric tetramethylfulvene complex [{(C₅Me₄CH₂)RuCl₂}₂] (3), which is in turn made by oxygenation (1 atm, 20°C, 30 min) of [{(C₅Me₅)RuCl₂}₂] (1); since both reactions proceed in high yield, 4 is a readily accessible starting material for a range of Cp*-substituted ruthenium complexes. The C-Cl in 4 is readily substituted by nucleophiles to give [(C₅Me₄CH₂X)Ru(CO)₂Cl] (X = OH, OMe, OEt, O-i-Pr, OPh, OCH₂Ph, NEt₂,H) and by PPh₃ (in the presence of NH₄PF₆) to give [(C₅Me₄CH₂PPh₃)Ru(CO) ₂Cl]PF₆. The Ru-Cl in the alkoxy complexes [(C₅Me₄CH₂OR)Ru(CO)₂Cl] is replaced by reaction with KX to give [(C₅Me₄CH₂OR)Ru(CO)₂X] (R = Me, X = Br, I, CN, SCN; R = Et, X = Br, I) and by PPh₃ in the presence of Ag⁺ to give [(C₅Me₄CH₂OEt)Ru(CO)₂(PPh ₃)]⁺. Reaction of 4 with KCN or KSCN in MeOH gave a mixture of C(C₅Me₄CH₂OMe)Ru(CO)₂X], [(C₅Me₅)Ru(CO)₂X], and [(C₅Me₄CH₂X)Ru(CO)₂X] (X = CN, SCN). The amines are quaternized; e.g., [(C₅Me₄-CH₂NEt₂)Ru(CO) ₂Cl] reacted with MeI to give [(C₅Me₄CH₂NEt₂Me)Ru(CO) ₂I]I. X-ray crystal structure determinations were carried out for [(C₅Me₄CH₂Cl)Ru(CO)₂Cl] (orthorhombic, a = 18.291(3) A?, b = 11.087(17) A?, c = 6.877(12) A?, V = 1394.6(4) A?³, Z = 4, D_c = 1.725 g cm^-3, space group Pnma (D_2h¹⁶, No. 62)) and [(C₅Me₄CH₂OEt)Ru(CO)₂(PPh ₃)I⁺(OTf)^- (triclinic, a = 10.496(12) A?, b = 12.509(9) A?, c = 12.738(7) A?, α = 90.25(5)°, β = 93.56(7)°, γ = 93.85(7)°, V = 1666(2) A?³, Z = 2, D_c = 1.491 g cm^-3, space group P1 (C_i¹ No. 2)).