Syntheses and study on nickel and copper complexes with 1,3,5-benzenetricarboxylic acid. Crystal and molecular structure of [Cu3(mdpta)3(btc)](ClO4)3 · 4H2O

Nickel and copper complexes containing 1,3,5-benzenetricarboxylic acid, with a combination of selected N-donor ligands and Schiff bases, of the composition Ni3(bimz)6(btc)2 · 12H2O (1), Ni3(btz)9(btc)2 · 12H2O (2), Ni2(L1)(btc) · 7H2O (3), Ni3(L2)2(Hbtc) · 9H2O (4), Ni2(L3)(btc) · 4H2O (5), Cu2(L4)(btc) · 7H2O (6), [Cu3(pmdien)3(btc)](ClO4)3 · 6H2O (7) and [Cu3(mdpta)3(btc)](ClO4)3 · 4H2O (8); H3btc = 1,3,5-benzenetricarboxylic acid, bimz = benzimidazole, btz = 1,2,3-benztriazole, L1 = 2-[(phenylimino)methyl]phenol, L2 = N,N′-bis-(salicylidene)propylenediamine, L3 = 2-{[(2-nitrophenyl)methylene]amino}phenol, L4 = 2-[(4-methoxy-phenylimino)methyl]phenol, pmdien = N,N,N′,N″,N″-pentamethyldiethylenetriamine, mdpta = N,N-bis-(3-aminopropyl)methylamine, have been synthesized. The complexes have been studied by elemental analysis, IR, UV–Vis spectroscopies, magnetochemical and conductivity measurements and selected compounds also by thermal analysis. The crystal and molecular structure of complex 8 was solved. The complex is trinuclear with btc3−-bridge. The coordination polyhedron around each copper atom can be described as a distorted square with a CuON3 chromophore formed by one oxygen atom of carboxylate and three nitrogen atoms of mdpta. The magnetic properties of 8 have been studied in the 1.8–300 K temperature range revealing a very weak antiferromagnetic exchange interaction with J = −0.56 cm−1 for g = 2.13(9). The antimicrobial activities against selected strains of bacteria were evaluated. It was found that only complex 5 is able to inhibit the growth of Staphylococcus strains.

Graphical abstractNickel and copper complexes bridged by the 1,3,5-benzenetricarboxylate anion, with N-donor ligands or Schiff bases in the coordination sphere, were prepared and characterized. X-ray analysis of the copper trinuclear complex proved a deformed square-planar arrangement of central atoms and coordination of carboxylato groups. The complex showed a very weak antiferromagnetic interaction among the central atoms.Figure optionsDownload full-size imageDownload as PowerPoint slide