SOLVENT-DEPENDENT H-2 NUCLEAR-MAGNETIC-RESONANCE SPECTRA AND SOLVATOCHROMISM IN LIGAND-FIELD ABSORPTION-BANDS OF CIS-[CRF2N4]-TYPE COMPLEXES WITH TRIETHYLENETETRAMINE, PYRIDINE OR 2,2'-BIPYRIDINE

The solvent-dependent H-2 NMR spectra and solvatochromism in ligand-fi eld absorption bands of cis [CCrF2N4]-type complexes with deuteriated triethylenetetramine (trien),pyridine (py)and 2,2'-bipyridine (bipy) h ave been used to demonstrate the; sensitivity of the angular overlap m odel parameters to the solvent co-ordination sphere, as has also been observed for trans[CrF2,([H-2(4)]dadad)](+) (dadad =1,10-diamino-4,7-d iazadecane). The cis effect was found to account reasonably well for t he solvent dependence of the spectra for both the cis and trans comple xes. The inverse correlation of the H-2 NMR chemical shifts for the be ta- and gamma-deuteyons in the py complexes and 4- and 5-deuterons in the bipy complexes with the solvent electron acceptor-number gave dire ct evidence for the pi-acceptor bond properties of aromatic heterocycl ic ligands:in the complexes.