The reaction of [Os3(μ-H)3(CO)9(μ3-COMe)] 1 with a slight excess of the sterically hindered base 1,8-diazabicyclo[5.4.0]undec-7-ene (dbu) affords the anion [Os3(μ-H)2(CO)9(μ3-COMe)] - 3 which has been isolated as its N(PPh3)2+ salt in high yield. Treatment of 3 with [Au(PPh3)]Cl in the presence of TIPF6 gives [Os3(μ-H)2(μ-AuPPh3)(CO) 9(μ3-COMe)] 4 in high yield. The cluster [Os3(μ-H)3(CO)9(μ3-CCl)] 2 reacts with 1 equivalent of dbu to produce a highly unstable species thought to be [Os3(μ-H)2(CO)9(μ3-CCl)] - which, in the presence of excess of dbu, gives the yellow compound [Os3(μ-H)2(CO)9(μ3-CN 2C9H16)] 5 in good yield. This reaction has been found to be general and the reaction of 2 with 1 equivalent of dbu in the presence of a twenty-fold excess of the required nucleophile Y gives the compounds [Os3(μ-H)2(CO)9(μ3-CY)] (Y = pyridine 6, quinoline 7, isoquinoline 8 or trimethyl phosphite 9). The molecular structures of complexes 4, 5, 7 and 9 have been established by single-crystal X-ray analysis. Both structural features and spectroscopic data for compounds 4-9 are consistent with a zwitterionic formulation of these species. Complex 7 exhibits a strong negative solvatochromism in a wide range of organic solvents, suggesting a less-polar excited state upon photoxcitation.
|Number of pages||8|
|Journal||Journal of the Chemical Society, Dalton Transactions|
|Publication status||Published - 1 Dec 1992|
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