Two Isostructural Dinuclear CuII and CoII Complexes With a Multidentate Bridging Ligand 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetic Acid

Abstract

Two isostructural complexes Cu2(PPA)2Br2(DMF)2 (1) and Co2(PPA)2Cl2(DMF)2 (2) are obtained via assembly of 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetic acid (HPPA) and CuII/CoII salts. Both complexes represent similar binuclear coordination structure containing a 12-membered metallocycle in which the asymmetric unit is composed of one metal center (CuII/CoII), one Br¯/Cl¯ anion, one PPA¯ ligand, and one coordinated DMF molecule. In complex 1, each CuII ion represents a distorted octahedral environment, which is defined by one Br atom, three oxygen atoms from one DMF molecule and the chelating carboxyl group of PPA¯, and two nitrogen atoms from the chelating pyridine and pyrazole rings of PPA. The ligand PPA¯ adopts the bridging fashion to facilitate the formation of binuclear coordination motif. For complex 2, the same structure can be obtained as that for 1 except that Cu and Br atoms are replaced by Co and Cl atoms, respectively. Thermal stability of both crystalline materials has been explored.