Synthesis and X-ray structures of some Group 6 metal carbonyl bis(2-pyridyl)formamidine complexes

New complexes of the types M(CO)4(HDpyF) (M=Cr, 1; M=W, 2) and Mo(CO)3(HDpyF)(CH3CN) (3), have been prepared by the reactions of bis(2-pyridyl)formamidine (HDpyF) with corresponding Group 6 metal hexacarbonyls in THF and CH3CN, respectively. The HDpyF ligands in complexes 1–3 coordinate to the metal centers in novel bidentate fashions but in different bonding modes. All the three complexes show supramolecular structures in the solid state by intermolecular hydrogen bonding and aromatic π–π stacking interactions.