Poly(methimazolyl)borate Alkyne Complexes of Molybdenum and Tungsten

Synthetic routes are reported to complexes of the form [MI(alkyne)(CO){H n B(mt) 4– n }] (mt = methimazolyl; n = 1, 2; M = Mo, W) through the reactions of alkyne complexes [WI 2 (HC≡CSiMe 3 ) 2 (CO) 2 ] or [MI 2 (RC≡CR) 2 (NCMe)(CO)] (M = Mo, W; R = Me, Ph) with the salts Na[H n B(mt) 4– n ].The derivative [MoI(PhC≡CPh)(CO){HB(mt) 3 }] reacts with Na[HB(mt) 3 ] to provide the complex [Mo(PhC≡CPh)(CO){HB(mt) 3 } 2 ] in which the two HB(mt) 3 ligands adopt different non‐interconverting coordination modes, κ 3 ‐ S , S′ , S″ and κ 1 ‐ S . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)