Organosulphur–transition-metal chemistry. Part 1. Reactions of carbon disulphide with metal carbonyl anions

Abstract

The trithiocarbonato-complex [N(PPh₃)₂][Mn(CO)₄(S₂CS)] is formed in high yield on treatment of [N(PPh₃)₂][ Mn(CO)₅] with CS₂ in tetrahydrofuran (thf) over 4 d. Reactions also occur between CS₂ and the iminium salts of [Re(CO)₅]^– and [Mo(CO)₃(η-C₅H₅)]^– but no products have been isolated. Methylation of [N(PPh₃)₂][ Mn(CO)₄(S₂CS)] with either Mel or SFO₂(OMe) gives [Mn(CO)₄(S₂CSMe)] in ca. 40% yield, but GeBrMe₃ or [PhN₂][BF₄] provide [Mn(CO)₄(S₂CSMe)] and [Mn(CO)₄(S₂CSPh)], respectively, in only small amounts. Low (<10%) yields of trithiocarbonato-complexes are produced when thf solutions of sodium salts of [M(CO)₅]^–(M = Mn or Re), [Fe(CO)₂(η-C₅H₅)]^–, [Mo(CO)₃(η-C₅H₅)]^–, and [M(CO)₄]^2–(M = Fe, Ru, or OS) are treated with CS₂ and Mel consecutively. Very small amounts of dimetal complexes [(OC)₄M(µ-S₂CS)M(CO)₅](M = Mn or Re) have also been isolated from reactions of [M(CO)₅]^– with CS₂ and Mel, with [graphic omitted](SMe) as an additional product from Na[Mn(CO)₅]. The complex [(OC)₄Re(µ-S₂CS)Re(CO)₅] is better obtained (45% yield) when Na[Re(CO)₅] is treated successively with CS₂ and [ReBr(CO)₅]. Analogous complexes [(OC)₄Mn(µ-S₂CS)Re(CO)₅] and [(OC)₄Re(µ-S₂CS)Mn(CO)₅] are similarly prepared. The effect of added sulphur on various reactions is described. Addition to [N(PPh₃)₂][Mn(CO)₅] causes an immediate colour change from yellow to red, i.r. spectroscopic evidence for the formation of [N(PPh₃)₂][MnS_n(CO)₅] being obtained. With CS₂ this species generates [N(PPh₃)₂][Mn(CO)₄(S₂CS)] slowly, while Mel gives [N(PPh₃)₂][MnI₂(CO)₄]. Possible mechanisms of trithiocarbonato-complex formation from CS₂ are discussed.