om050391w_si_002.cif (48.13 kB)

Complex Formation and Rearrangement Reactions of the Phosphine Hydride Anions [OsH3(PPh3)3]- and [IrH2(PPh3)3]-

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posted on 02.01.2006 by Gemma Guilera, G. Sean McGrady, Jonathan W. Steed, Aled L. Jones
[OsH4(PPh3)3] (1) reacts with KH in THF in the presence of 18-crown-6 to form [K(THF)(18-crown-6)][OsH3(PPh3)3] (2), characterized by NMR spectroscopy and X-ray crystallography; cation−anion contact is achieved through three Os−H···K moieties. In contrast, [IrH3(PPh3)3] (6) reacts with KH and 18-crown-6 in THF with redistribution of ligands to produce the known bis-phosphine complex [K(18-crown-6)][IrH4(PPh3)2] (7). This reaction has been followed by NMR spectroscopy, and [IrH2(PPh3)3]- has been identified as a likely intermediate. K[OsH3(PPh3)3] (3) reacts with Bun3SnCl to form the tin-osmium complex [OsH3(SnBun3)(PPh3)3] (8), characterized by NMR spectroscopy and X-ray crystallography. The molecule contains a seven-coordinate osmium center, which can be described approximately as a distorted fac-[OsH3(PPh3)] arrangement, with the SnBun3 moiety capping the OsH3 face.