The 2D–3D networks with infinite channels or difform chains of copper(II) complexes via weak non-covalent interactions

Abstract

A series of new copper(II) complexes with pyridine–carboxylate ligands: [Cu 2(μ-Cl) 2(pda) 2][Cu(MeOH)(H 2O) 4]·H 2O ( 1), [CuBr(pda)(MeOH)] 2[Cu(H 2O) 5]·MeOH ( 2), [Cu 2(μ-Br) 2(pda) 2][Cu(H 2O) 4]·[CuBr 2(H 2O) 2] ( 3) and [CuNa 2(μ-sna) 2]·4H 2O ( 4) (H 2pda=pyridine-2,6-dicarboxylic acid, H 2sna=2-sulfinonicotinic acid), have been synthesized and structurally characterized. The weak non-covalent interactions of π–π stacking and hydrogen bonding between the pyridine–carboxylate ligands extend complexes 1– 4 into supramolecular architectures, where complexes 1 and 3 possess 2D networks with wave-like chains or straight chains, while complexes 2 and 4 show 2D layers and 3D networks with infinite 1D channels, respectively. The polycrystalline powder EPR spectra of complexes 1, 3 and 4 indicate that their unpaired electrons are placed in d x 2 − y 2 or d z 2 orbitals of the ground state of Cu(II). The UV/vis, IR spectra and TG analyses for complexes 1– 4 are also discussed.