The UV-light initiated reaction of organosilanes with tungsten hexacarbonyl: Formation of an organosilylene complex and organosilylium salts

摘要

UV-irradiation of the diorganosilane [4-tBu-2,6-(P(O)(OiPr) _2J_2C_6H_2]SiH_2Ph in the presence of W(CO)_6 provided a mixture consisting of the diorganosilylene tungsten pentacarbonyl complex [4tBu-2,6-{P(O)(OiPr) _2)_2C_6H_2](Ph)SiW(CO)_5 (2), the organosilylium salt [4-tBu-2,6-{P(O)(OiPr)_2}_2C _6H_2Si(H)Ph]~+[{(CO)_5W}_2H]- (3), and an unidentified species. UV-irradiation of the triorganosilane [4-tBu2,6-{P(O)(OiPr)_(22)}_2C_6H _2]SiHPh_2 in presence of W(CO)_6 provided the organosilylium salt [4-tBu-2,6-(P(O)(OiPr)_2}_2C _6H_2SiPh_2]~+[ ((CO)_5W} _2H]- (6) whereas, under the same conditions, no reaction was observed between the tetraorganosilane [4-tBu-2,6-(P(O)(OiPr) _2J2?C_6H_2]SiPh_3 and W(CO) _6. The reaction of compound 2 with Ph_3C~+PF _6~- gave the fluorine-substituted silylene complex [4-tBu-2,6-{P(O)(OiPr)_2}_2C_6H _2](F)SiW(CO)_5 (4) whereas the reactions of 3 with Ph _4PBr and 5 with water gave the benzoxasilaphospholes 3a, 3b, and 7, respectively. The compounds 2 and 6 were isolated and characterized by ~1H, ~(13)C, 29Si, ~(31)P NMR, and IR spectroscopy, electrospray ionization mass spectrometry, and in case of 2 also by single-crystal X-ray diffraction analysis. The compounds 3, 3a, 3b, 4, and 7 were not isolated but identified unambiguously by NMR spectroscopy and electrospray ionization mass spectrometry.