Yong-Hong Wan

Hydrothermal synthesis and structural studies of novel 2-D lanthanide coordination polymers with phthalic acid

This paper presents four lanthanide coordination polymers, [Ln2(BDC)3(H2O)]n (Ln = La, 1; Ln = Eu, 2; Ln = Tb, 3; BDC = 1,2-benzenedicarboxylate) and [Yb4(BDC)6(H2O)2]n (4) prepared by the hydrothermal technique. They are all 2-D infinite structures with BDC anions connecting adjacent metal ions. In complex 1, La(III) ions are eight- and nine-coordinated, and all La(III) ions are coplanar in the 2-D structure. In complexes 2 and 3, Eu(III) and Tb(III) ions are also eight- and nine-coordinated, but they are distributed in a wave-like 2-D network. In complex 4, the Yb(III) ions have four different coordination numbers (6, 7, 8 and 9), which are rarely found in one lanthanide complex. Both the coordination numbers and the arrangement of Ln atoms in these coordination polymers show the lanthanide contraction. In the four complexes, all the oxygen atoms of BDC take part in coordination with Ln(III) ions, adopting tetra-, penta- and hexadentate coordination modes for the phthalate anions. The luminescent properties of complex 2 have been investigated and the results for the explanation of the chemical environment of the Eu(III) ion are consistent with the X-ray analysis.

Hydrothermal synthesis and crystal structure of neodymium(III) coordination polymers with isophthalic acid and 1,10-phenanthroline

Abstract Two polymeric complexes, [Nd2(bdc)2(Hbdc)2(H2O)]n·nH2O (1) and [Nd2(bdc)3(phen)(H2O)]n·nH2O (2) (H2bdc=isophthalic acid; phen=1,10-phenanthroline) were synthesized and characterized by IR spectra, TGA, and X-ray crystallography. In complex 1, the Nd(III) ions are bridged by bdc2− and Hbdc− in three modes to form a two-dimensional layer. Adjacent layers are linked by hydrogen bonds composed of coordinated and lattice water molecules, together with carboxylate groups, forming a three-dimensional network. In complex 2, the Nd(III) ions are connected by bdc2− ligands in three modes into a two-dimensional layer. Weak CH⋯O hydrogen bonding interactions between the chelated phen ligands and the carboxylate O atoms across adjacent layers result in a three-dimensional network.

Three new lanthanide coordination polymers containing isophthalate and 1,10-phenanthroline

Abstract Three lanthanide coordination polymers were prepared by hydrothermal synthesis and characterized by single-crystal X-ray diffraction. [Pr 2 (mBDC) 3 (phen)(H 2 O)] n ·0.5 n H 2 O ( 1 ) (mBDC=isophthalate, phen=1,10-phenanthroline) exhibits two kinds of metal environments (coordination numbers 7 and 8). In complex 1 , mBDC ligands adopt the tetradentate (bridging and bridging) coordination mode and connect Pr ions into an undulating layer, and a 3D supramolecular structure is formed via hydrogen bonds between adjacent layers. [Tb 4 (mBDC) 6 (phen)] n ( 2 ) has three types of metal environments (coordination numbers 6, 7 and 8) and is composed of a 3D network formed by mBDC linking Tb ions via tetradentate (bridging and bridging) and pentadentate (bridging/chelating and bridging) coordination modes. There are two kinds of small quadrilateral channels along the a -axis. [Er 4 (mBDC) 6 (phen)] n ( 3 ) is isostructural to complex 2 .

Hydrothermal synthesis and crystal structures of three novel lanthanide coordination polymers with glutarate and 1,10-phenanthroline

Abstract The first series of lanthanide coordination polymers with glutarate (glu) and 1,10-phenanthroline (phen), [Nd2(glu)3(phen)2]n 1, [Tb(glu)(phen)Cl]n 2 and [Ho(glu)(phen)Cl]n 3, have been prepared by hydrothermal reaction and characterised by IR spectra and X-ray crystallography. In complex 1, there are two different conformations for glutarate ligands, the gauche- and anti-forms. Nd(III) ions are bridged by glutarate ligands in three modes to form 2D layer structure. Phen ligands coordinate to Nd(III) ions in chelating mode and protrude from the polymeric layer in two different directions. Two types of π–π interactions exist between two adjacent layers. In complex 2, Tb(III) ions are connected by glutarate ligands into 1D chain structure. Phen ligands coordinate to Tb(III) ions in chelating mode and locate at both sides of the chain. The C–H⋯O, C–H⋯Cl weak hydrogen bonds and π–π stacking interactions between chains result in 3D supramolecular structure. Single-crystal X-ray diffraction analysis shows that complex 3 is isostructural with complex 2.

Water cluster supported architecture of lanthanide coordination polymers with pyrazinetricarboxylic acid

The first examples of lanthanide coordination polymers with pyrazinetricarboxylic acid, [Ln(PZTA)(H2O)4]·2H2O (Ln = Eu(1), Gd (2), PZTA = pyrazine-2,3,5-tricarboxylate) and [Ln(PZTA)(H2O)2]·H2O (Ln = Er(3), Yb(4)) were synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. Structural analysis shows that complexes 1 and 2 are composed of 1-D lanthanide-pyrazinetricarboxylate (Ln-PZTA) framework and two types of water clusters while complexes 3 and 4 have 3-D Ln-PZTA framework with 1-D channel, at which a 1-D water cluster chain is located. This shows the effect of lanthanide contraction on the construction of the Ln-PZTA framework. The results of TG curves and PXRD display that the uncoordinated and coordinated water molecules are removed, the Ln-PZTA frameworks collapse, which shows that the water clusters play an important role in constructing Ln-PZTA frameworks in the title complexes.