The Photochemistry of M3(CO)12 (M = Ru, Os) with Pyrazole and Its Substituted Derivatives

The photochemistry of M3(CO)12 [M = Ru (1a), Os (1b)] with pyrazole, 3,5-dimethylpyrazole, and 3,5-diphenylpyrazole is documented. With 1a, photolysis with pyrazole leads to the substitution product HRu3(CO)10(C3H3N2) (2a). In the case of 1b, the initial product is the ortho-metallated species HOs3(CO)10(C3H3N2) (3b), heating of which yields HOs3(CO)10(C3H3N2) (2b). Photolysis of 1a and 1b with 3,5-dimethylpyrazole yields HRu3(CO)10(C3HMe2N2) (4a) and HOs3(CO)10(C3HMe2N2) (4b), respectively. The molecular structure of 4b has been determined by X-ray crystallography. There is no reaction on photolysis of 1a and 1b with 3,5-diphenylpyrazole.