The reaction of [Os3(μ-H)(CO)10(μ-CO)]− with Ph2SbCl: a cluster with a six-membered Os4Sb2 ring and another with fluxional metal–metal bonds

Abstract

Besides the cluster [Os₃(μ-H)(μ-SbPh₂)(CO)₁₀], 1, other products identified from the reaction of [Os₃(μ-H)(CO)₁₀(μ-CO)]⁻ with Ph₂SbCl in THF were [Os₃(μ-SbPh₂)₂(CO)₁₀], 2a, and a dimeric form of 1, viz. [Os₃(μ-H)(μ-SbPh₂)(CO)₁₀]₂, 3. Carrying out the reaction in CH₂Cl₂ gave 3 as the major product, while 2a has been demonstrated to result from the reaction of 1 with Ph₂SbCl. In 2a the Os₃Sb₂ unit is almost planar; one of the Ph₂Sb bridges is open while the other is closed. The two Ph₂Sb-bridged Os–Os edges are shown by EXSY and variable-temperature ¹H NMR spectroscopy on the analogue [Os₃(CO)₁₀(μ-SbPh₂){μ-Sb(C₆H₄Me-p)₂}], 2b, to interchange via an Os–Os bond fluxion.