Synthesis, Reactivity, and Characterization of the First Donor-Stabilized Silylene Complexes of Osmium meso-Tetra-p-tolylporphyrin (TTP)Os=SiR2•THF (R = Me, Et, 1Pr) and the Molecular Structure of (TTP)Os=SiEt2•2THFOrganometallics
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AbstractThe preparation and characterization of the first donor-stabilized silylene complexes of osmium meso-tetra-p-tolylporphyrin are described. The silylene complex (TTP)Os=SiM~·THF (l·THF) is prepared by the reaction of [Os(TTP)b with hexamethylsilacyclopropane. Treating K2[0s(TTP)] with Cl2Si~ also generates the silylene complexes (TTP)Os=SiR2·THF [R =Me (l·THF), Et (2·THF), ipr (3·THF)]. 1H NMR spectroscopy indicates that, in solution, one molecule of THF is coordinated to the silicon in all of these complexes. This has been verified by 2D-NOESY experiments. In 2·THF, the methylene protons are diastereotopic, indicating that the silicon is pyramidalized. Addition of 1 equiv of pyridine to l·THF or 2·THF replaces the THF on silicon with pyridine. Coordination of pyridine to silicon was also confirmed by a 2D-NOESY experiment. The structure of 2·THF was determined by a single-crystal X-ray diffraction experiment. The diethyl complex 2·2THF crystallizes with two additional THF molecules as solvates in the monoclinic space group P2d c with a = 21.649 (5) A, b = 13.829 (3) A, c = 19.526 (3) A, 13 = 98.08 (2) 0 , V = 5788 (4) A3, Z = 4, R = 5.0%, and Rw = 5.7%. The Os-Si distance (2.325 (8) A) is the shortest observed to date. Other metrical parameters of this complex are discussed.
Copyright OwnerAmerican Chemical Society
Citation InformationL. Keith Woo, Daniel A. Smith and Victor G. Young. "Synthesis, Reactivity, and Characterization of the First Donor-Stabilized Silylene Complexes of Osmium meso-Tetra-p-tolylporphyrin (TTP)Os=SiR2•THF (R = Me, Et, 1Pr) and the Molecular Structure of (TTP)Os=SiEt2•2THF" Organometallics Vol. 10 Iss. 12 (1991) p. 3977 - 3982
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