STABILIZATION OF TCNQ ANION RADICAL WITH DI- AND TRIAMINE COMPLEXES OF NICKEL AND COPPER

摘要

The reactivity of the organic acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) in its neutral or anionic radical forms with saturated di- and triamino derivatives of nickel and copper such as the cationic complexes with ethylenediamine, [M(en)(3)](2+), trimethylenediamine, [M(tn)(2)(H2O)(2)](2+), and diethylenetriamine, [M(dien)(2)](2+), is discussed on the basis of the metal environment stability. The products obtained show either substitution of some labile ligands from the metal coordination sphere and a-coordination of the anionic TCNQ or alternatively displacement of the counter-ion by anionic TCNQ with maintenance of the coordination around the metal. The complexes studied show the TCNQ groups forming dimeric, or trimeric, anionic associations with strong antiferromagnetic intradimer coupling between the radical units. The complex [Ni(dien)(2)](TCNQ)(2) shows a weaker TCNQ-TCNQ coupling with a singlet-triplet equilibrium observable at temperatures above 60 K from its contribution to the total magnetic susceptibility of the complex. [References: 25]