Tian Shi

Two Compounds Constructed from Bimolybdenum-Capped Sandwich-Type Tetra-Ni-molybdogermanate and N-Donor Multidentate Ligand

Two organic-inorganic hybrid bimolybdenum-capped tetra-Ni(II) sandwich-type molybdogermanates, namely, (H2L)4[Ni4(H2O)2{B-α-GeMo9O34 (MoO2)}2]·6H2O (1), [Ni2(HL)4(H2O)2][Ni4(H2O)2{B-α-GeMo9O34(MoO2)}2]·12H2O (2), L = 2,4,5-tri(4-pyridyl)imidazole, were prepared with hydrothermal synthesis method and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction, thermogravimetric analysis, and single-crystal X-ray diffraction. Their magnetic properties and electrochemical properties were investigated. The results show that compounds 1 and 2 contain a new bimolybdenum-capped sandwich-type heteropolymolybdate anion, [Ni4(H2O)2{B-α-GeMo9O34(MoO2)}2](8-). The compound 1 is a zero-dimensional supramolecular compound, and the supramolecular architecture of compound 2 is constructed from covalent layers through hydrogen bonds and π-π interaction. The two compounds both present electrocatalytic activities for the reduction of nitrite.

Synthesis, characterization and properties of lanthanide coordination polymers with 3,5-bis(4-carboxyphenylmethyloxy) benzoic acid

Two types of coordination polymers based on a flexible tripodal multicarboxylate ligand and lanthanide metal ions, namely, [Ln(L)]·4.5H2O (Ln = La (1), Ce (2), Nd (3), named as type I) and [Ln(L)(H2O)2]·3.5H2O (Ln = Er (4), Tm (5), Yb (6), Lu (7), named as type II) (H3L = 3,5-bis(4-carboxyphenylmethyloxy)benzoic acid), have been hydrothermally synthesized and characterized structurally. Single-crystal X-ray diffraction analyses revealed that compounds 1–3 are isostructural, and they crystallize in the orthorhombic Pbcn space group with a 3D framework. In contrast, isomorphic compounds 4–7 exhibit 2D networks in the monoclinic C2/m space group, and were synthesized under experimental conditions similar to 1–3. The structural diversities reveal that the lanthanide contraction has a significant effect on the structural self-assembly process. The PXRD patterns of the hydrated, dehydrated and rehydrated samples of 5 show that the dehydration–rehydration process of 5 is reversible, based on which the alcohol sorption property of 5 was explored. Magnetic susceptibility studies of 2–5 have been carried out, which indicated a antiferromagnetic interaction. The solid-state luminescent behaviors of 2, 3 and 6 were investigated at room temperature. 3 and 6 exhibit the unique emissions of Nd and Yb, respectively.

Syntheses, Structures and Properties of Two Transition Metal-Flexible Ligand Coordination Polymers

Two coordination polymers based on 3,5-bis(4-carboxyphenylmethyloxy) benzoic acid (H3L), [M(HL)]·2H2O M = Mn(1), Co(2), have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction and further characterized by elemental analysis, IR spectra and TGA. The two complexes possess 3D framework with diamond channels resulting from the trans-configuration of the flexible ligand and three coordination modes, 3(η2, η1), 2(η1, η1), η1, of carboxyl groups in the ligand. The framework can be represented with Schläfli symbol of (48·66)(47·66). The wall of the channel consists of left- or right-handed helical polymeric chains. UV–visible–NIR and photoluminescence spectra, magnetic properties of 1 and 2 have also been discussed.