Luminescence behavior of tetraaza macrocylic nickel (II) complexes and non-linear Stern–Volmer quenching

Macrocylic dicarbinolamine nickel (II) complexes with diimine moiety in their ligand exhibited luminescence, when irradiated at their charge transfer band. The Stern–Volmer (S–V) plots of one of the complexes in DMF medium exhibited positive curvature, when FeC13 was used as a quencher, while the same complex showed negative curvature when nitrobenzene was used as a quencher. The mechanism for the luminescence quenching of the macrocyclic complex has also been discussed.