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Three lanthanide compounds have been synthesized, namely, {[Dy2(bpda)3(H2O)3]4·2H2O}(Dy-1), {[Sm(bpda)2·(H2O)]·H2O}n (Sm-2) and {[Tb2(bpda)3(H2O)3]4·2H2O} (Tb-3) (H2bpda = 2,2′-bipyridine-6,6′-dicarboxylic acid). Their structures were determined by single crystal X-ray diffraction and characterized by elemental analysis, infrared spectroscopy and thermogravimetric analysis. Dy-1 and Tb-3 are isostructural with a conjugate bimolecular four-nuclear cluster structure constructed with intramolecular hydrogen bonds and they form a 3D supramolecular structure with intermolecular hydrogen bonding. Sm-2 is a one-dimensional chain structure and is further connected by intricate hydrogen bonds into a three-dimensional supramolecular structure. These three compounds exhibit significant characteristic luminescence from the ligand to the central Ln(III) ion, which is found by solid-state photoluminescence measurement. Sm-2 exhibits a long luminescence lifetime and high fluorescence quantum yield. A slow relaxation phenomenon is observed for the dysprosium compound by measuring the alternating-current susceptibility at low temperature and the underlying mechanism was further confirmed by theoretical calculations.

With deprotonated 2-(4-nitro phenyl)-, 2-(4-methyl phenyl)-, and 2-(4-methoxy phenyl) imidazoled-2,9-dimethyl-1,10-phenanthroline (NPIP, MPIP and MoPIP) as nitrogen ligands, as well as bis[2-(diphenylphosphino) phenyl]ether (DPEphos) as phosphorus ligand, three Cu(I) neutral complex has been synthesized and characterized by infrared spectroscopy (IR), elemental analysis and 1H NMR methods. TG-DTA shows that the complex begins to decompose when the temperature reached about 220 oC, indicating their high thermo-stability. The emission spectrum shows that the complexes exhibit yellow emission with a peak emission wavelength of 576, 585 and 596 nm under excitation of 287 nm in powder state.

A luminescent europium metal-organic framework[Eu(Hbptc)(H2O)3]n (1) has been successfully prepared by the facile hydrothermal reaction of Eu(NO3)3 ⋅ 6H2O and the π-conjugated ligand H4bptc (H4bptc = biphenyl-2,3,3′,5′-tetracarboxylic acid). Single crystal structure analysis reveals that 1 exhibits a 2D layered structure. The luminescence studies revealed that this material can be selectively and sensitively quenched or enhanced by some small organic molecule solvents, showing potential as fluorescence probe.

A new 1-D calcium complex [Ca(H2bptc)(H2O)3]n (1) (H4bptc = biphenyl-2,3,3′,5′-tetracarboxylic acid) were obtained by hydrothermal reaction. X-ray diffraction analysis shows that complex 1 crystallizes in the monoclinic space group P2(1)/c with a = 14.3376(13), b = 11.3116(10), c = 11.9099(11), β = 114.0740(10), V = 1763.6(3)A3, Z = 4, Dc = 1.591 g·cm−3, μ = 0.417 mm−1, F(000) = 872, and the final R1 = 0.0310, wR2 = 0.0812 for I>2σ(I). Central Ca(II) ion is seven-coordinated and exhibits a distorted pentagonal bipyramidal geometry. Additionally, the IR, TG, UV-Vis absorption, and luminescence properties of 1 have been investigated.

Reaction between silver salt and conjugational N-hetrocyclic carboxylic acid with the presence of bipyridyl skeletons auxiliary ligand afforded a d10 metal polymer namely [(ddpp)Ag(bipy) (1)] (ddpp = 2, 5-di(2′,4′-dicarboxylphenyl)pyridine, bipy = 4,4′-bipyridine). It was characterized by elements analysis, infrared spectroscopy, single crystal X-ray diffraction and thermogravimetry studying. For the polymer 1, silver centers are three coordinated geometry with an ON2 donor set provided by ddpp and bipy. The polymer 1 is built from 1-D alternative/zig-zag chain, as the secondary building unit, and further stacks via hydrogen bonds which formed between two isophthalic moieties of ddpp ligands and weak interactions to generate a two-dimensional, 2D supramolecular layer. Moreover, the polymer 1 displays thermal stability in solid state and the luminescence behaviour is also investigated in a dimethyl sulphoxide solution at ambient temperature, and it also can be applied in design of sensors to detect of trace aluminum, zinc and calcium ion.

The reactions in mixtures of lanthanide oxides and biphenyl-2,3,3′,5′-tetracarboxylic acid, in the presence of aqueous solution, result in two interesting lanthanide–organic coordination polymers, formulated as{[Eu(Hbptc)(H2O)4]·H2O}n (1) and [Sm(Hbptc)(H2O)3]}n (2), (H4bptc = biphenyl-2,3,3′,5′-tetracarboxylic acid). The polymers 1 and 2 are built from 2D corrugated layer. The 2D layers are further interconnected to form the 3D framework by hydrogen bonds between water molecules and carboxyl groups. Both the complexes 1 and 2 exhibit efficient sensitized luminescence in the visible region in the solid state based on characterization emission of europium(III) and samarium(III) ions, respectively.

Hydrothermal reactions of biphenyl-2,3,3′,5′-tetracarboxylic acid (H4bptc) with zinc salts in the presence of 1,4-bis(2-pyridylmethyl)piperazin (bpmp) and 4,4-dipyridyl (dpy) afforded the coordination polymers {[Zn2(bptc)(bpmp)]·3H2O}n (1) and {[Zn(H2bptc)(dpy)]·3H2O}n (2). Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, IR spectroscopy, and TG analyses. Complex 1 displays an unusual three-dimensional (3D) supramolecular motif generated by hydrogen bonding interactions between two single-layered 2D networks. Complex 2 represents a 2D layer structure, and such layers are further united together into three-dimensional supramolecular structure through intricate hydrogen bonding. In addition, luminescence properties of complexes 1 and 2 were also investigated.