Influence of Metal Identity in Bipyridine-Based Metal-4N Complexes With Formate

We present the vibrational spectra of a series of dicationic, organometallic complexes consisting of a transition metal center (Co, Ni, or Cu) coordinated by 4,4′-di­(tert-butyl)-2,2′-bipyridine (DTBbpy) ligands and a formate adduct. Spectral features are analyzed and assigned through comparison with density functional theory calculations, and structures are reported. Natural population analysis shows that the DTBbpy ligands serve as flexible charge reservoirs in each complex. Shifts in the vibrational signatures of the formate moiety reveal that the nature of the metal center plays a crucial role in the charge distribution and formate–metal binding motif in each complex, illustrating the impact of the metal center on the structural and electronic properties of these complexes.