Highly reduced organometallics Part 49. Reaction of hexacarbonyltitanate(2−) with azobenzene. Structural characterization of the first hydroxo-carbonyl of titanium [Ti2(μ-OH)2(CO)8]2−

Hexacarbonyltitanate(2−) reacts with azobenzene to provide 40–65% yields of [Ti(PhNNPh)(CO)4]2−, which is formulated as a 1,2-diphenylhydrazido dianion adduct of zerovalent titanium tetracarbonyl. The latter undergoes very facile hydrolysis to provide 1,2-diphenylhydrazine and the first hydroxo-carbonyl of titanium [Ti2(μ-OH)2(CO)8]2−, which has been structurally characterized as the [K(18-crown-6)]+ salt.