Solvent-dependent2H nuclear magnetic resonance spectra and solvatochromism in ligand-field absorption bands of cis-[CrF2N4]-type complexes with triethylenetetramine, pyridine or 2,2′-bipyridine

Abstract

The solvent-dependent 2H NMR spectra and solvatochromism in ligand-field absorption bands of cis-[CrF2N4]-type complexes with deuteriated triethylenetetramine (trien), pyridine (py) and 2,2′-bipyridine (bipy) have been used to demonstrate the sensitivity of the angular overlap model parameters to the solvent co-ordination sphere, as has also been observed for trans-[CrF2([2H4]dadad)]+(dadad = 1,10-diamino-4,7-diazadecane). The cis effect was found to account reasonably well for the solvent dependence of the spectra for both the cis and trans complexes. The inverse correlation of the 2H NMR chemical shifts for the β- and γ-deuterons in the py complexes and 4- and 5-deuterons in the bipy complexes with the solvent electron acceptor number gave direct evidence for the π-acceptor bond properties of aromatic heterocyclic ligands in the complexes.