Synthesis, structure, and reactivity of. beta. -MoCl/sub 2/

A new synthetic route, utilizing the reaction between Mo/sub 2/(O/sub 2/CCH/sub 3/)/sub 4/ and AlCl/sub 3/ in refluxing chlorobenzene, has afforded a reactive form of ..beta..-M0Cl/sub 2/. Infrared, UV-visible reflectance, and X-ray photoelectron spectroscopic studies show that ..beta..-MoCl/sub 2/ preparations obtained by both the new and older methods with those of the tetranuclear rectangular cluster compound M0/sub 4/Cl/sub 8/(PEt/sub 3/)/sub 4/ and its coupled condensation product (Mo/sub 4/Cl/sub 8/(PEt/sub 3/)/sub 2/)/sub x/ suggests the existence of the tetranuclear units in the structure of ..beta..-MoCl/sub 2/. Direct conversion of ..beta..-MoCl/sub 2/ to Mo/sub 4/Cl/sub 8/(PEt/sub 3/)/sub 4/ by reaction with triethylphosphine at room temperature substantiates this view. 19 references, 3 figures, 3 tables.