Reactions of an osmium bis(dihydrogen) complex under ethylene: Phosphine addition to a C–C double bond and C–H bond activation of fluoroarenes

Abstract

The bis(dihydrogen) complex [OsTp(η2-H2)2(PiPr3)]BF4 (1; Tp = hydridotris(pyrazolyl)borate) reacts with ethylene under 2 atm of the gas to afford [OsTp(CH2CH2PiPr3)(η2-CH2═CH2)2]BF4 (2), which promotes the CH bond activation of fluorobenzene and 1,3-difluorobenzene to give OsTp(3-C6H4F)(η2-CH2═CH2)2 (3) and OsTp(3,5-C6H3F2)(η2-CH2═CH2)2 (4), respectively, releasing [EtPiPr3]BF4. The formation of 2 takes place via [OsTp(η2-CH2═CH2)2(PiPr3)]BF4 (5), which has been isolated and characterized by X-ray diffraction analysis.