Visible light induced formation of a tungsten hydride complex.

When irradiated with blue light in the presence of a Lewis base (L), [CpW(CO)] undergoes metal-metal bond cleavage followed by a disproportionation reaction to form [CpW(CO)L] and [CpW(CO)]. Here, we show that in the presence of pyridinium tetrafluoroborate, [CpW(CO)] reacts further to form a metal hydride complex CpW(CO)H. The rection was monitored through photo H NMR spectroscopy experiments and the mechanism of light-driven hydride formation was investigated by determining quantum yields of formation.