Synthesis of Os3W alkylidyne and alkylidene clusters by solid-state pyrolysis; direct C–O bond cleavage of co-ordinated ketenyl ligand
Abstract
The heterometallic tetranuclear ketenyl compound [Os3(CO)10(µ-H){C(O)CH2W(CO)3(η-C5Me5)}]1 possessing a pendant W(η-C5Me5)(CO)3 substituent is prepared by condensation of [Os3(CO)10(NCMe)2] with the aldehyde complex [W(η-C5Me5)(CO)3(CH2CHO)]. Pyrolysis of 1 in the solid state at 185 °C afforded four tetrahedral compounds [WOs3(η-C5Me5)(CO)9(µ-O)(µ3-CMe)]2, [WOs3(η-C5Me5)(CO)9(µ-O)(µ-H)(µ-CHMe)]5, [WOs3(η-C5Me5)(CO)11(µ3-CMe)]3 and [WOs3(η-C5Me5)(CO)11(µ3-CH)]4, demonstrating a unique example of C–O bond scission for the ligated ketene fragment. Since treatment of 2 with H2 in toluene also afforded 5 in moderate yield, it is highly probable that the latter is produced via reaction with trace amounts of H2 generated from the decomposition of 1. The molecular structures of 2 and 4 have been determined by single-crystal X-Ray analysis.