One pot synthesis of η3-butadienyl complexes of Mo(II) or W(II): Crystal structure of [MoCl(CO)2(η3-CH2C(CONHCH2CCH)CCH2)(2,2′-bipyridine)]

A one pot reaction of [M(CO)4L2] (M = Mo, L2 = 2,2′-bipyridine, 1,10-phenanthroline; M = W, L2 = 2,9-dimethyl-1,10-phenanthroline) with 1,4-dichloro-2-butyne and Ph4PCl was examined in chlorinated solvents over the range 40–129 °C. Production of either [MCl(CO)2(η3-CH2C(COCl)CCH2)L2] (4) or [MCl2(CO)(η2-ClCH2CCCH2Cl)L2] was found to be dependent upon the solvent temperature, and these reactions were found to be insensitive to the presence of water. Under controlled conditions, one pot reactions carried out in the presence of alcohols, amines or thiols gave related ester, amide or thioester substituted η3-butadienyl complexes in good yield. The structure of the propargyl amide complex was confirmed by X-ray analysis.

Graphical abstractComplexes of the type [MCl(CO)2(η3-CH2C(COX)CCH2)L2] (M = Mo, W; L2 = 2,2′-bipy, 1,10-phen, 2,9-dimethyl-1,10-phen; X = Cl, NHR, NR2, OR, SR) were obtained from one pot reactions of [M(CO)4L2], 1,4-dichloro-2-butyne and Ph4PCl in chlorinated solvents below 60 °C (Mo) or above 81 °C (W). Destabilization of X = Cl occurred at elevated temperatures to give the alternative product [MCl2(CO)(η2-ClCH2CCCH2Cl)L2].Figure optionsDownload full-size imageDownload as PowerPoint slide