Reaction of [(CO)4Mo(μ-Cl)3Mo(SnCl3) (CO)3] with PhCCPh.: X-ray crystal structure of [Mo3 (μ3-O)(μ3-Cl) (μ2-Cl) (μ2-OH)2(O) (η2-PhCCPh)5]

Reaction of [(CO4Mo(mu -Cl)(3)Mo(SnCl3)(CO)(3)] 1 with PhC equivalent to CPh in inert atmosphere affords the mixture of alkyne halocarbonyl compounds, which after exposure to moist air rearranges to give the complex [Mo-3(mu (3)-O)(mu (3)-Cl)(mu (2)-Cl)(mu (2)-OH)(2) (O)(eta (2)-PhC equivalent to CPh5)] 2. The structure of complex 2 was established by X-ray crystallography. The molecule consists of a nearly isosceles triangle of Mo atoms joined by triply bridging oxygen and chlorine atoms. Compound 2 is noteworthy since it is the first trinuclear complex of molybdenum in which a mixed-valence (Mo2MoIV)-Mo-II core has been established. (C) 2001 Elsevier Science B.V. All rights reserved.