Chemistry of di- and tri-metal complexes with bridging carbene or carbyne ligands. Part 26. Reactions of the compounds [PtW{µ-σ:η3-CH(C6H4Me-4)}(CO)2(PR3)2(η-C5H5)][BF4](PR3= PMe3, PMe2Ph, or PMePh2) and [PtW{µ-σ:η3-C(Me)C6H4Me-4}(CO)2(PMe3)2(η-C5H5)][SO3CF3] with nucleophiles; X-ray crystal structure of [PtW(µ-H){µ-CH(C6H4Me-4)}(CO)2(PMe3)2(η-C5H5)]
Abstract
The salts [PtW{µ-σ:η3-CH(C6H4Me-4)}(CO)2(PR3)2(η-C5H5)][BF4] react with carbon monoxide and with tertiary phosphines to afford, respectively, the complexes [PtW{η-CH(C6H4Me-4)}(CO)3(PR3)2(ηC5H5)][BF4](PR3= PMe3, PMe2Ph, or PMePh2) and [PtW{µ-CH(C6H4Me-4)}(CO)2-(PR3)3(η-C5H5)][BF4](PR3= PMe3 or PMe2Ph), whereas treatment with K[BH(CHMeEt)3] or tetra-alkylammonium halide gives the species [PtW(µ-H){µ-CH(C6H4Me-4)}(CO)2(PR3)2(η-C5H5)](PR3= PMe3 or PMe2Ph) and [PtWX{µ-CH(C6H4Me-4)}(CO)2(PR3)2(η-C5H5)](X = Cl, Br, or I, PR3= PMe3; X = I, PR3= PMe2Ph), respectively. N.m.r. data (1H, 13C-{1H}, 31P-1H}, and l95Pt-{1H}) are reported, and discussed in relation to the structures of the compounds. In solution, the bridged hydrido-complexes exist as an equilibrium mixture of diastereoisomers. An X-ray diffraction study of [PtW(µ-H){µ-CH(C6H4Me-4)}(CO)2(PMe3)2(η-C5H5)] confirmed that the metal–metal bond is spanned by the CH(C6H4Me-4) and H ligands [Pt–W 2.895(1), Pt–µ-C 2.109(9), and W–µ-C 2.259(9)Å], that the tungsten atom carries two terminally bonded CO groups and the η-C5H5 ligand, and that the platinum atom is part of a cis-Pt(PMe3)2 group. The platinum is in an essentially planar environment with the angle between the planes defined by PtP2 and Pt(µ-C)W being only 7°. Crystals are monoclinic, space group P21/c; the structure has been refined to R 0.039 for 3 083 reflections measured to 2θ= 50° at 220 K. Some reactions of the salt [PtW{µ-σ:η3-C(Me)C6H4Me-4}(CO)2(PMe3)2(η-C5H5)][SO3CF3] have also been studied. Thus PMe3, K[BH(CHMeEt)3], and NaH afford, respectively, the compounds [PtW{µ-C(Me)C6H4Me-4}-(CO)2(PMe3)3(η-C5H5)][SO3CF3], [PtW(µ-H){µ-C(Me)C6H4Me-4}(CO)2(PMe3)2(ηC5H5)], and [PtW{µ-C(C6H4Me-4)![[double bond, length half m-dash]](https://www.rsc.org/images/entities/char_e006.gif)
CH2)}(CO)2(PMe3)2(η-C5H5)]. N.m.r. data show that the PMe3 adduct and and the hydrido-species exist in solution as mixtures of diastereoisomers.
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