Syntheses, crystal structures and luminescence properties of two copper(II) complexes with terpyridine and dicarboxylate ligands

Syntheses, crystal structures and DNA-binding activities of divalent Fe, Cu, Zn and Cd complexes with 4′-(furan-2-yl)-2,2′:6′,2″-terpyridine

Five coordination complexes [Fe(ftpy)2](ClO4)2·(H2O)2 (1), [Cu(ftpy)(NO3)(H2O)](NO3) (2), [Cu(ftpy)2]2(ClO4)4·(C2H5OH) (3), [Zn(ftpy)2]·(ClO4)2·(H2O)1.5 (4) and [Cd(ftpy)2]2(ClO4)4·(C2H5OH) (5) (ftpy=4′-(furan-2-yl)-2,2′:6′,2′-terpyridine) have been synthesized and characterized by IR, elemental analysis and single-crystal X-ray diffraction. With the exception of 4, all complexes adopt normal homoleptic [M(ftpy)2]2+ motifs. In the crystal, both hydrogen bonds and face-to-face interactions between furyl and pyridyl rings facilitate the construction of three-dimensional networks. The DNA-binding activities of the five complexes have been investigated by fluorescence emission titration at room temperature suggesting an intercalative mode for 1–3 with a relative order, 3>2>1, and a combined static and dynamic mode for 4 and 5.

Enhanced third-order nonlinear optical properties determined in thin films using the Z-scan technique: bis(μ-4,4′-oxydibenzoato)bis[(4′-phenyl-2,2′:6′,2′′-terpyridine)cobalt(II)]

π-Conjugated organic materials exhibit high and tunable nonlinear optical (NLO) properties, and fast response times. 4′-Phenyl-2,2′:6′,2′′-terpyridine (PTP) is an important N-heterocyclic ligand involving π-conjugated systems, however, studies concerning the third-order NLO properties of terpyridine transition metal complexes are limited. The title binuclear terpyridine CoIIcomplex, bis(μ-4,4′-oxydibenzoato)-κ3O,O′:O′′;κ3O′′:O,O′-bis[(4′-phenyl-2,2′:6′,2′′-terpyridine-κ3N,N′,N′′)cobalt(II)], [Co2(C14H8O5)2(C21H15N3)2], (1), has been synthesized under hydrothermal conditions. In the crystal structure, each CoIIcation is surrounded by three N atoms of a PTP ligand and three O atoms, two from a bidentate and one from a symmetry-related monodentate 4,4′-oxydibenzoate (ODA2−) ligand, completing a distorted octahedral coordination geometry. Neighbouring [Co(PTP)]2+units are bridged by ODA2−ligands to form a ring-like structure. The third-order nonlinear optical (NLO) properties of (1) and PTP were determined in thin films using the Z-scan technique. The title compound shows a strong third-order NLO saturable absorption (SA), while PTP exhibits a third-order NLO reverse saturable absorption (RSA). The absorptive coefficient β of (1) is −37.3 × 10−7 m W−1, which is larger than that (8.96 × 10−7 m W−1) of PTP. The third-order NLO susceptibility χ(3)values are calculated as 6.01 × 10−8 e.s.u. for (1) and 1.44 × 10−8 e.s.u. for PTP.