Reactivity of [WCl(SnCl3)(CO)3(NCMe)2] towards tBuCCH.: X-ray crystal structure of [WCl(CO)(tBuCCH)(NCMe)(PPh3)2]2[SnCl6]

In the reaction of [WCl(SnCl3)(CO)3(NCMe)2] with tert-butylacetylene the very labile bis(alkyne) complex [WCl(SnCl3)(CO)(tBuCCH)2(NCMe)] has been observed as the major product by means of IR and NMR spectroscopy. The latter compound in reaction with two equivalents of PPh3 in CH2Cl2 solution gives very poorly soluble purple crystals of the tungsten(II) cationic complex. The crystal structure of this compound consists of the discrete [SnCl6]2− anion, two independent [WCl(CO)(tBuCCH)(NCMe)(PPh3)2]+ cations and four MeCN (solvent) molecules. This is the first crystallographically characterized cationic chlorocarbonyl complex of tungsten(II) containing a terminal alkyne as ligand.