Synthesis and Spectroscopic Characterization of Group 6 Pentacarbonyl(4-substituted pyridine)metal(0) Complexes

Carbonyl-metal (M:Cr, Mo, W) derivatives of 4-substituted pyridines [4-methylpyridine (4-mp), 4-tert-butylpyridine (4-tbp) and 4-dimethylaminopyridine (4-dmap)] where the metal center is bonded to the nitrogen atom of the substituted pyridine ring are described. The organometallic complexes, M(CO)₅L, were synthesized by either the direct reaction of the metal hexacarbonyls or by the thermal substitution of M(CO)₅(THF) with the pyridine ligands; 4-methylpyridine (1), 4-tert-butylpyridine (2), 4-dimethylaminopyridine (3). The reported complexes were purified by column chromatography and recrystallization. The complexes were all characterized in solution by elemental analysis, MS, ir , ¹H-nmr and ¹³C-nmr spectroscopies.