Zn(<scp>ii</scp>) and Cu(<scp>ii</scp>) coordination polymers assembled from V-shaped tetracarboxylate ligands and N-donor ancillary ligands: syntheses, structures and properties

Abstract

Six novel zinc(II) and cupric(II) metal coordination polymers with V-shaped ligands and N-donor ligands, [Zn2(SA)(phen)2]·2H2O (1), Zn2(FA)(phen)2(H2O)·H2O (2), Cu3(H2FA)3(phen)3·H2O (3), Cu(H2FA)(2,2′-bipy)·1.54(H2O) (4), [Cu2(SA)(4,4′-bipy)1.5]·2.7(H2O) (5) and [Zn2(SA)(4,4′-bipy)2]·8H2O (6) (H4SA = 3,3′,4′,4′-diphenyl-sulfonetetracarboxylate acid, H4FA = 4,4′-(hexafluoroisopropylidene)diphthalic acid, phen = 1,10-phenanthroline, 2,2′-bipy = 2,2′-bipyridine and 4,4′-bipy = 4,4′-bipyridine), have been synthesized and structurally characterized by elemental analysis, IR and X-ray diffraction. Complex 1 has a two-dimensional (2D) layer network, whereas complex 2 exhibits a 1D helical chain structure because of the introduction of a H4FA ligand. Complex 3 shows a complicated 2D framework. Complex 4 has a 1D chiral structure with an open channel by incorporating the auxiliary ligand 2,2′-bipy, while complexes 5 and 6 have a complicated 3D framework which is of particular interest because it adopts interesting and rare framework topologies. The results indicate that the multicarboxylate H4SA and H4FA ligand can adopt varied coordination modes in the formation of the complexes and the configuration and flexibility of the ligands play a key role in directing the related properties of the complexes. The photoluminescence properties of H4SA and H4FA, 1, 2, 6 were studied in the solid state at room temperature. Moreover, nonlinear optical measurements showed that 4, 5 displayed a second-harmonic-generation (SHG) response of 0.8 and 0.7 times that for urea, respectively.