Transition metal coordination networks based on 1,3-bis(1,2,4-triazol-1-yl)benzene and isophthalic acid: Luminescence and magnetic properties

Abstract

Solvothermal reactions of 1,3-bis(1,2,4-triazol-1-yl)benzene (btb), isophthalic acid (H2ip) with M(NO3)2 (M = Co2+(1), Cu2+(2), Cd2+(3)) afforded three coordination polymers, [M(btb)(ip)]n (Co2+(1), Cu2+(2)) and [Cd2(btb)(ip)2·4H2O]n·4H2O (3), respectively. Both compounds 1 and 2 show 2D networks with binuclear paddle-wheel structures, however 3 is confirmed as 1D double-chain ladder. For complex 1, weak ferromagnetic interactions are detected between CoII ions of Co2 unit without long-range magnetic ordering. Antiferromagnetic interactions are found between the CuII centers in complex 2. In addition, complex 3 shows red-shifted luminescence spectra with obviously higher intensity owning to the more rigid arrangement of the π systems.