Photochemical Conversion of H2Os3(CO)10(P-Donor) to H2Os3(CO)9(P-Donor) in Solution and on High Surface Area Silica.

摘要

Near-UV irradiation of H2Os3(CO)10L yields conversion to the known coordinatively unsaturated H2Os3(CO)9L for L = PPh3 or PPh2Et in alkane solution at 298 K. Likewise, near-UV irradiation of an alkane suspension of (Si02)-L'Os3(CO)10H2 yields (Si02)-L'Os3(CO)9H2 where (Si02)-L'Os3(CO)10H2 is the solid prepared by reaction of high surface area Si02 with H2Os3(CO)10-(PPh2CH2CH2Si(OEt)3). The same photochemistry results at 77 K in rigid alkane glasses, but the initial (less than 5% conversion) product is not derived from loss of CO. Continued irradiation at 77 K yields H2Os3(CO)9L and CO, but H2Os3(CO)9L is only found in approx. 50% yield based on the amount of H2Os3(CO)10L consumed. Warming the irradiated sample to 298 K yields some regeneration of H2Os3(CO)10L and some additional H2Os3(CO)9L.