The ruthenium complex (η5-C4Ph4COHOC4Ph4-η5)(μ-H)(CO) 4Ru2 and its phenyl ring- substituted derivatives were found to act as efficient catalysts in reduction reactions of aldehydes and ketones to alcohols, using formic acid as H source. Excess formic acid accelerates the reaction, and the corresponding formate esters were isolated as sole products. Turnover numbers of up to 8000 (alcohols) and 11 000 (formate esters) were ...