Mixed complexes of group VIb metal carbonyls

Article abstract of DOI:10.1021/ic50046a008

Forty-nine new mixed derivatives - which contain two different noncarbonyl substituent groups - of the group VIb metal carbonyls are reported. These are of the types M(CO)₃X₂Y and M(CO)₂X₂Y₂ where M = Cr, Mo, W; X₂ = 2,2′-dipyridyl (dipy) or o-phenanthroline (phen); and Y = various monodentate Lewis bases. Carbonyl stretching frequencies for many derivatives containing strongly π-accepting Y ligands yield complex Cotton-Kraihanzel force constants; real force constants may be obtained if the two physically different cis-CO-CO interactions are differentiated in a physically reasonable way. Evidence is presented that N,N′-dimethylformamide (DMF) and acetamide exhibit normal coordination through oxygen in the complexes Mo(CO)₃(phen)(DMF) and Mo(CO)₃(phen)(acetamide).