No abstract

No abstract

The CuII atom in the title salt, (C5H7N2)2[Cu(C2O4)2]·2H2O, is located on a center of inversion and is chelated by two oxalate groups in a square-planar coordination geometry. The cation, anion and water mol­ecules inter­act through hydrogen bonds, forming a three-dimensional hydrogen-bonded network.

Guo (2008) Preparation and characterization of a metal-organic three-dimensional framework based on isonicotinate [Pb(INA) 2 ] (INA = isonicotinate, NC 5 H 4 -4-), Journal of Coordination Chemistry, The coordination compound [Pb(INA) 2 ] (INA ¼ isonicotinate, NC 5 H 4 -4-CO À2 ) has been synthesized and characterized by elemental analysis, FT-IR spectra and thermogravimetric analysis. Its structure was confirmed by X-ray crystallography. The single-crystal X-ray data of this compound show a three-dimensional wave-like metal-organic framework as a result of INA ligand bridging. The lead atom has an unsymmetrical eight-coordinate geometry, coordinated by two nitrogen atoms and six oxygen atoms from the INA ligand. The arrangement of the INA ligands exhibits a coordination gap around the Pb atom occupied possibly by a stereoactive lone pair of electrons on lead(II), with the coordination around lead atoms being hemidirected. There are -stacking interactions between adjacent parallel INA ligands which act as a pillar that increases the gap in the coordination geometry around Pb(II). Photoluminescence properties of the compound have been examined in the solid state at room temperature. The compound has photoluminescence with maximum emission located in the UV region.

This work presents an investigation on the positions of the substituent and N-donor auxiliary chelating ligand (bipy/phen) effect on engineering of crystalline architectures of four Pb(II) complexes with a pair of methyl-substituted 3-sulfobenzoic isomers: [Pb(4-msba)(phen)(H2O)] (1), [Pb (4-msba)(bipy)(H2O)]-H2O (2), [Pb(5-msba)(phen)2] 9H2O (3), and [Pb2(5-msba)2(bipy)2(H2O)2] (4) (4/5-msba = 4/5-methyl-3-sulfobenzoate, phen= 1,10-phenanthroline and bipy = 2,2'-bipyridine). The lead(II) ions exhibit hemidirected geometry in 1-4. The positions of the methyl as well as the auxiliary chelating ligands infiuence coordination modes of the sulfonates and thus determine the architectures. As the position of methyl in aromatic ring changes from 4 to 5, the structures change from 2-D sheet-like compounds for 1 and 2 to 0-D dimeric species for 3 and 4. A water cluster (H20)is exists in 3, which flirther assembles into a water tape with a new pattern T4(3)4(3)10(3) A4. Complex 3 loses crystallinity rapidly in the open air and turns into [Pb(5-msba)(phen)2] 2H2O (3A). Thermal stabilities and solid state fluorescent properties of 1, 2, 3A, and 4 have been studied.