Tricarbonyl(carbaborane) complexes of the Group 6 metals as reagents for preparing heteronuclear dimetal compounds involving platinum
- 1 January 1993
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 2,p. 281-289
- https://doi.org/10.1039/dt9930000281
Abstract
The reagents Tl2[M(CO)3(η5-C2B9H9Me2)](M = Cr, Mo or W), generated in situ from Tl[TlC2B9H9Me2] and [M(CO)3(NCMe)3], react in thf (tetrahydrofuran) with the compounds [PtCl2L2](L = PPh3 or PEt3) to give the dimetal complexes [MPt(CO)3L2(η5-C2B9H9Me2)]. NMR studies revealed that the tungsten–platinum species were produced as a mixture of two isomers of formulation [WPt(CO)3L2(η5-C2B9H9Me2)] and [WPt(µ-H)(µ-σ:η5-C2B9H8Me2)(CO)3L2]. The complexes [MPt(CO)3L2(η6-C2B10H10Me2)] have been prepared from reactions between [PtCl2L2] and Na2[M(CO)3(η6-C2B10H10Me2)](M = Mo or W), with the latter generated in situ from Na2[C2B10H10Me2] and [M(CO)3(NCMe)3]. Similar reactions using [PtCl2(cod)](cod = cycloocta-1,5-diene), followed by addition of PPh3 to the reaction mixture, afforded the salts [PtH(PPh3)3][MPt(µ-σ:η6-C2B10H9Me2)(CO)4(PPh3)]. Protonation (HBF4·Et2O) of the latter yields the complexes [MPt(CO)4(PPh3)(η6-C2B10H10Me2)]. An X-ray crystallographic study of the molybdenum–platinum compound revealed that the molecule contained a Mo–Pt bond [2.814(1)Å] spanned by the nido-C2B10H10Me2 cage such that the latter is η6-co-ordinated to the molybdenum and linked to the platinum via a three-centre two-electron B–H⇀Pt bond. This bond involves the hydrogen atom attached to the boron atom which is β to the carbons is the CBCBBB face of the cage ligating the molybdenum atom. The NMR data (1H, 13C-{1H}, 31P-{1H} and 11B-{1H}) for the new compounds are discussed in relation to the structures proposed.Keywords
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