Heterobinuclear Complexes of Manganese and Molybdenum Containing Amino Acidato and Related O,N and S,N Bridges

The addition of NaOMe to [MnMo(CO)6(μ-S2CPCy3)(μ-Br)] (1) produces [MnMo(CO)6(μ-S2CPCy3)(μ-OMe)] (2), containing a methoxide bridge between Mn and Mo. Compound 2
reacts with α-amino acids to yield, upon elimination of MeOH, the complexes [MnMo(CO)5(μ-S2CPCy3){μ-OC(O)CR1R2NR32}] (3a−f), in which the oxygen atom of the carboxylato group
acts as a bridge between Mn and Mo, while the amino function coordinates the molybdenum
atom, displacing one carbonyl ligand. In a similar reaction, the addition of ethanolamine to
2 affords the μ2(O)-η2(O,N)-aminoethanolato complex [MnMo(CO)5(μ-S2CPCy3)(μ-OCH2CH2NH2)] (4). Reaction of 2 with cysteine methyl ester hydrochloride and NaOMe affords [MnMo(CO)5(μ-S2CPCy3){μ-SCH2C(COOMe)NH2}] (5), with the sulfur atom in the bridging position.
The new complexes have been characterized by analytical and spectroscopic methods, and
their structures have been determined by X-ray crystallography for 2, 3e (2,2-dimethylaminobutyrato), and 4.