Synthesis and structural characterisation of [Os6(CO)12(η6-C6H6)2]

Abstract

Reaction of [Os₄H₂(CO)₁₂]^2– with [Os(η⁶-C₆H₆)(MeCN)₃][BF₄]₂ in CH₂Cl₂ affords the pentanuclear cluster [Os₅H₂(CO)₁₂(η⁶-C₆H₆)] which upon treatment with 1,8-diazabicyclo[5.4.0]undec-7-ene in CH₂Cl₂ gives the dianion [Os₅(CO)₁₂(η⁶-C₆H₆)]^2–, whose subsequent reaction with [Os(η⁶-C₆H₆)(MeCN)₃][BF₄]₂ provides the new bis(benzene) cluster [Os₆(CO)₁₂(η⁶-C₆H₆)₂] in ca. 40% yield; the crystal structure of [Os₆(CO)₁₂(η⁶-C₆H₆)₂] shows that the six osmium atoms adopt a bicapped tetrahedral geometry with both benzene ligands in terminal η⁶ sites but co-ordinated to two osmium atoms with different metal connectivities.