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The hydrothermal reaction of silver nitrate and 2,2′-phosphinico-dibenzoic acid (H3L) with different metal to ligand ratios under hydrothermal conditions yielded two unusual complexes with the formulae of [Ag(H2L)]n (1) and [Ag3(L)]n (2). Both complexes were well characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopic and fluorescence studies. Complex 1 crystallizes in a centrosymmetric Pbcn space group and presents a two-dimensional (2D) layer structure through silver(I)-aromatic interaction, whereas complex 2 adopts a noncentrosymmetric Iba2 space group, in which the different coordination modes of the four groups around the phosphorus atom in the L3− ligand occurs. Both complexes display green emissions, assigned as the ligand-to-metal charge-transfer character.

Five novel hybrid compounds, [Mo8O26Cu2(4-abpt)2]n·4nH2O (1), (4-H2abpt)2[Mo8O26] (2), [Mo8O26Cu2(3-abpt)2(H2O)2]n (3), [MoO4Cu(3-abpt)(H2O)]n (4), and [Mo6O19Co(3-abpt)2]n·4nH2O (5) were prepared by reacting MoO3/(NH4)6Mo7O24 with 4-amino-3,5-bis(3/4-pyridyl)-1,2,4-triazole (3/4-abpt) and corresponding metal salts. Compound 1 is a 2D coordination polymer containing extended γ-[Mo8O26]4− and [Cu2(4-abpt)2]4+ ribbons. Compound 2 is a supramolecular hybrid aggregate composed of H-bond linking β-[Mo8O26]4− and 4-H2abpt2+. Compound 3 exhibits a 2D rectangular network constructed by isolated β-[Mo8O26]4−clusters and [Cu2(3-abpt)2]4+. In compound 4, each MoO42− anion links two Cu(II) ions to form a S-type [CuMoO4]n chain, which is further linked by bidentate 3-abpt to form a 2D wave-like network. In complex 5, unprecedented cyclic [Mo6O19]2−cluster links two neighbouring hexamolybdates and two Co(II) ions to form a 2D [CoMo6O19]n network, which is further pillared by tetradentate 3-abpt to generate a 3D metal–organic framework. These compounds are thermally stable under 250 °C. The composites of the final residues were analyzed by PXRD.

Hydrothermal reaction of Ln(NO3)·6H2O with benzimidazole-5,6-dicarboxylic acid (H3bidc) and KSCN afforded a series of new two- and three-dimensional coordination polymers, namely [Ln2(Hbidc)2(SO4)(H2O)3]n (Ln = La (1), Pr (2), Sm (3), Gd (4)) and [Ln4(Hbidc)4(SO4)2]n·2nH2O (Ln = Eu (5), Tb (6), Dy (7), Er (8)). The sulfates were in situ generated by catalytic oxidation of KSCN. These complexes were characterized by single crystal X-ray diffraction, IR spectroscopy, thermal analysis, fluorescent spectra and magnetic measurements. Complexes 1–4 are isomorphous and comprise a 2D network based upon planar tetranuclear lanthanide secondary building units. The 2D layers extend to a 3D framework by π–π stacking between imidazole rings and hydrogen bonding interactions. The complexes 5–8 are also isomorphous and have similar 3D frameworks fabricated through Hbidc2− and SO42− bridging dinuclear lanthanide secondary building units, and the guest water molecules are trapped in the lattice. The luminescent properties of complexes 5 and 6 exhibit characteristic europium and terbium luminescence, while 4 involves ligand-to-metal charge transfer. The magnetic properties of four complexes were also investigated.