Synthesis and Characterization of Allylic Dinuclear Molybdenum Complexes with Bridging Oxygen and Sulfur Containing Ligands

Complexes of the type [NEt 4 ][{Mo(CO) 2 (η 3 -C 3 H 5 )} 2 (μ-L) 3 ] and [Na(thf) x ][{Mo(CO) 2 (η 3 -C 3 H 5 )} 2 (μ-L) 3 ] (L = OC 2 H 5 , SC 2 H 5 , OPh, SPh, OC 6 H 4 CH 3 , and SCH 2 Ph) were synthesized using two different methods. The first was by the reaction of the starting material [Mo(CO) 2 (CH 3 CN) 2 (η 3 -C 3 H 5 )Cl] with NaSR or NaOR and [NEt 4 ] + , using 2:3 (metal:ligand) mole ratio in thf at room temperature. The second was by the in situ reactions of the ligands with the intermediate [Mo(CO) 2 (CH 3 CN) 2 (η 3 -C 3 H 5 )(thf)] + , which was generated by reacting the starting material [Mo(CO) 2 (CH 3 CN) 2 (η 3 -C 3 H 5 )Cl] with Ag[BF 4] . The complexes were characterized by means of IR, NMR, and elemental analysis. The X-ray structure of the complex [NEt 4 ][{Mo(CO) 2 (η 3 -C 3 H 5 )} 2 (μ-SC 6 H 5 ) 3 ] was determined, and cyclic voltammetery measurements for the complexes [NEt 4 ][(Mo(CO) 2 (η 3 -C 3 H 5 )} 2 (μ-SC 6 H 5 ) 3 ] and [NEt 4 ][{Mo(CO) 2 -(η 3 -C 3 H 5 )} 2 (μ-OC 6 H 4 CH 3 ) 3 ] were carried out. The OC 6 H 4 CH 3 complex exhibited a reversible oxidation wave at ca. 0.1 V whereas the SC 6 H 5 complex did not.