Two dimensional coordination polymers with 3,3′-thiodipropionate: An unprecedented coordination mode and strong hydrogen-bond network

Abstract

Four novel coordination polymers, namely [Co(μ3-tdp)(ina)2]n (1), [Cu(μ3-tdp)(ina)2]n (2), [Zn(μ3-tdp)(ina)2]n (3) and [Zn(μ3-tdp)(na)2]n (4) [tdp: 3,3′-thiodipropionate, ina: isonicotinamide and na: nicotinamide], were synthesized and structurally characterized by elemental analysis, IR and single-crystal X-ray diffraction techniques. Each M(II) ion (M(II)Co(II) in 1, Cu(II) in 2, Zn(II) in 3 and Zn(II) in 4) is coordinated by two nitrogen atoms of two different pyridine rings and four oxygen atoms from three different tdp ligands, forming distorted octahedral geometries. The tdp ligand exhibits an unprecedented coordination mode, namely the μ3-κO,O′:κO″:κO″′-bridging mode. Single crystal X-ray diffraction analysis results demonstrated that complexes 1–4 exhibit 2D layers with a point symbol of 33·43·54, which are extended into 3D supramolecular frameworks by R22(8) hydrogen-bonding motifs. Thermal analysis results showed that 2D complexes are stable up to 225, 189, 196 and 162°C, respectively. Moreover, the photoluminescent properties of complexes 3 and 4 were investigated at room temperature.