Synthesis and Crystal Structure of a 1-D Coordination Polymer {[Cu(NIT4py)_2(ip)]·6H_2O}_n

A new complex { [Cu（NIT4py）2（ip）]·6H2O }, （NIT4py=2-（4＂-pyridinyl）-4,4,5,5-tetra methylimidazoline-1-oxyl-3-oxide and ip = isophthalate dianion） has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in orthorhombic, space group Cmcm with a = 25.161（3）, b =10.045（1）, c = 15.450（2） A°, C32H48N6O14CU, Mr = 804.30, V= 3904.8（8） ,A°^3, Z = 4, De = 1.368 g/cm^3, μ（MoKa） = 0.630 mm^-1, F（000） = 1692, the final R = 0.0326 and wR = 0.0787 for 1843 independent reflections with Rint = 0.0372. Each Cu（Ⅱ） ion is four-coordinated by two carboxylate oxygen atoms and two pyridyl-N atoms from NIT4py radicals to furnish a rhombus geometry. The central Cu（Ⅱ） ion is located at an inversion center and a crystallographic two-fold axis. Each isophthalate dianion binds two Cu（Ⅱ） ions in bis-monodentate mode, leading to a 1-D chain, a＇ these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.

Synthesis and Crystal Structure of a New One-dimensional Zn(II) Nitronyl Nitroxide Complex Bridged by Pyridine-2,4-dicarboxylate Anion

A new one-dimensional （1-D） Zn（Ⅱ） nitronyl nitroxide complex bridged by pyridine-2,4-dicarboxylate anion, [Zn（NIT4Py）（2,4-PDA）（H2O）2], （NIT4Py = 2-（4′-pyridyl）-4,4,5,5- tetramethylimidazoline-1-oxyl-3-oxide and 2,4-PDA = pyridine-2,4-dicarboxylate anion）, has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 16.834（2）, b = 7.4376（10）, c = 18.295（3） A, β = 102.848（2）°, V = 2233.2（5） A^3, C19H23N4O3Zn, Mr = 500.78, Dc = 1.489 g/cm^3,μ（MoKa） = 1.152 mm^-1, F（000） = 1036, Z = 4, the final R = 0.0390 and wR = 0.0915 for 3234 observed reflections. In the complex, each zinc（Ⅱ） ion is six-coordinated by one nitrogen atom of the radical ligand （NIT4Py）, one nitrogen atom and two oxygen atoms of two 2,4-PDA anions and two oxygen atoms of two water molecules. Each 2,4-PDA anion bridges two Zn（Ⅱ） ions via a tridentate mode into a 1-D chain, and these 1-D chains are further linked into a 2-D network via hydrogen-bonding interactions.

Synthesis and Crystal Structure of a New Zn(II) Nitronyl Nitroxide Complex [Zn(NIT4Py)(PDA)(H_2O)_3]

A new Zn（Ⅱ） nitronyl nitroxide complex [Zn（NIT4Py）（PDA）（HzO）3] （NIT4Py = 2-（4＇-pyridyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2PDA = pyridine-2,5-dicarboxylic acid） has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P2 1/c with a = 16.881（8）, b = 7.356（4）, c = 18.857（9） A°,β = 108.616（6）°, V = 2219.1 （19）A°^3 ,C 19H25N4O9Zn, Mr = 518.80, Dc = 1.553 g/cm^3, μ（MoKa） = 1.165 mm^-1, F（000） = 1076, Z = 4, the final R = 0.0269 and wR = 0.0715 for 3193 observed reflections with I 〉 2σ（I）. The complex exists as discrete mononuclear molecules and the zinc（Ⅱ） ion is six-coordinated with one radical ligand （NIT4Py）, one bidentate pyridine-2,5-dicarboxylate anion and three water molecules. A three-dimensional network structure is formed through the intermolecular interactions.

Synthesis, Crystal Structure and Optical Properties of a New Nd(III) Nitronyl Nitroxide Complex [Nd(NIT2Py)_2(NO_3)_3]

A new Nd（Ⅲ） nitronyl nitroxide complex [Nd（NIT2Py）2（NO3）3] （NIT2Py = 2-（2＇-pyridyl）-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide） has been synthesized and structurally characterized by X-ray diffraction. It crystallizes in monoclinic, space group P21/n with a = 12.396（4）, b =11.134（4）, c = 23.360（7） A°, β = 98.178（6）°, V= 3191.2（18） A°^3, C24H32N9NdO13, Mr = 798.83, Dc =1.663 g/cm^3, μ（MoKa） = 1.704 mm^-1, F（000） = 1612, Z = 4, the final R = 0.0425 and wR = 0.0957 for 6532 independentreflections with Rint = 0.0642 and 4552 observed reflections （I 〉 2σ（I））. The complex exists as discrete mononuclear molecules and the neodymium（Ⅲ） ion is ten-coordinated with three bidentate nitrate anions and two radical ligands （NIT2Py） via bidentate chelating mode.The optical properties of the complex are discussed.

Copper(Ⅱ)-lanthanoid(Ⅲ)-copper(Ⅱ) trinuclear complexes with N,N'-bis(2-aminopropyl)-oxamido ligand

Six novel μ-oxamido trinuclear complexes, namely Cu_2(oxap)_2Ln(ClO_4)_3 (Ln: La, Pr, Nd, Gd, Yb, Ho), where oxap is N,N'-bis(2-aminopropyl)oxamido, have been synthesized. The complex Cu_2(oxap)_2Gd(ClO_4)_3 was characterized with variable temperature magnetic susceptibility (4-300 K). The exchange integrals J (Cu-Gd) and J'(Cu-Cu) were found to be 0.83 cm^(-1) and -1.62 cm^(-1), indi- cating that very weakly ferromagnetic spin-exchange interaction operates between Cu(II) and Gd (III) ions.