Cluster chemistry. XXXXVIII. Some reactions of Ru₃(CO)₁₂ with nitrogen heterocycles. X-ray crystal structures of Ru₃(μ-CO)₂(CO)₈(bipy) and Ru₃(μ-H){μ-N₂C₃H(CF₃)₂-3,5}(CO)₁₀

Abstract

Reactions between Ru3(CO)12 and the nitrogen heterocycles pyridine, 2,2′-bi-pyridyl, pyrazole, 3,5-dimethylpyrazole and 3,5-bis(trifluoromethyl)pyrazole are described. Pyridine afforded the cyclometallated complex Ru3(μ-H)(μ-NC5H4)(CO)10, which with excess pyridine formed Ru3(μ-H)2(μ-NC5H4)2(CO)8. 2,2′-Bipyridyl gave purple Ru3(μ-CO)2(CO)8(bipy), shown by an X-ray structure to have an Fe3(CO)12-type structure, with the bipy chelating one of the CO-bridged Ru atoms. The pyrazoles gave Ru3(μ-H)(μ-N2CP3HR2)(CO)10 (R = H, Me or CF3), in which the pyrazolide ligand spans an RuRu bond also bridged by H, as shown by the X-ray structure of the CF3 derivative. The bipyridyl and pyrazole complexes both crystallise in the monoclinic system, the former in space group P21/n with unit cell dimensions a 7.834(2), b 25.818(2), c 11.717(1) Å, β 107.41(1)° with Z = 4 and the latter in space group P21/c, unit cell dimensions a 16.802(3), b 7.726(1), c 18.807(3) Å, β 114.24(1)° with Z = 4. The structures were refined by conventional least-squares methods with the use of 3336 (2993 for the pyrazole structure) reflections with I > 2.5σ(I) to final R = 0.031 and Rw = 0.034 (0.025 and 0.026).