Reactions of [Os3(CO)10(μ-dppm)] and [HOs3(CO)8{μ3-Ph2PCH2P(Ph)C6H4}] with Bu3GeH: Ge-H and Ge-C bond cleavage at triosmium centers

The reactivity of the triosmium clusters [Os-3(CO)(10)(mu-dppm)] [dppm = bis(diphenylphosphino)methane] and [HOs3(CO)(8){mu(3)-Ph2PCH2P(Ph)C6H4}] with tributylgermanium hydride (Bu3GeH) has been investigated. Oxidative addition of Bu3GeH to [Os-3(CO)(10)(mu-dppm)] at 110 degrees C affords [HOs3(CO)(9)(GeBu3)(mdppm)] (1) which undergoes further decarbonylation upon prolonged heating to yield [H2Os3(CO)(7)(GeBu3){mu(3)-Ph2PCH2P(Ph) C6H4}] (2) and [HOs3(CO)(8)(GeBu3)(mu-GeBu2)(m-dppm)] (3). Control experiments confirm the bimodal formation of 2 and 3 from 1 during thermolysis. Cluster 2 reacts with additional Bu3GeH at 140 degrees C to give [Os-3(CO)(6)(mu-GeBu2)(2){mu(3)-PhP(C6H4)CH2P(Ph)C6H4}] (4), a thermolysis product also produced from 3. In contrast, oxidative addition of Bu3GeH to [HOs3(CO)(8){mu(3)-Ph2PCH2P(Ph)C6H4}] occurs at room temperature to afford [H2Os3(CO)(8)(GeBu3){mu(3)-Ph2PCH2P(Ph)C6H4}] (5), which decarbonylates at 110 degrees C to yield 4. All new clusters have been characterized by elemental analyses and spectroscopic methods, and the molecular structures established by X-ray crystallography. Electronic structure calculations on the different hydride isomers based on 1 and 5 are reported. (C) 2019 Elsevier B.V. All rights reserved.