Chang-Ju Wu

Synthesis, crystal structure and magnetism of 1D cobalt(II) coordination polymer with thiocyanate as bridging ligand

A one-dimensional coordination polymer [Co(μ 1,3-NCS)2(npdo)2] n (npdo = 4-nitropyridine N-oxide) has been synthesized and structurally determined by X-ray crystallography. The complex crystallizes in the orthorhombic space group of Pbcn with a = 22.688(5) Å, b = 7.2636(17) Å, c = 10.299(2) Å. Adjacent Co(II) ions are coordinated by two μ 1,3-SCN− bridging ligands, forming a one-dimensional chain along the c axis and the npdo coordinates to Co(II) ion as a terminal ligand. The thermal variation of the magnetic moments of the complex reflects the antiferromagnetic interaction between the bridged Co(II) ions above 20 K and the ferromagnetic transition or the strong short-range spin interaction below 20 K.

Synthesis, Crystal Structure and Fluorescence of A 1-D Polymeric Zinc(Ii) Complex with Pyrazine-2-Carboxylate as a Bridging Ligand

A one-dimensional chain complex {[Zn(pyz)(SCN)(H2O)2]·H2O}∞ (pyz = pyrazine-2-carboxylic anion) has been synthesized and its crystal structure determined by X-ray crystallography. The complex crystallizes in an orthorhombic system and the space group is P2 12121 with a = 6.873(3), b = 9.847(4), c = 16.466(7) Å. The Zn(II) ion is located in a distorted octahedral environment with two oxygen atoms O(3) and O(4) from terminal ligands of two water molecules, another oxygen atom O(1) from the carboxylate group of pyz, and three nitrogen atoms, N(1), and N(2A) from two different pyz and N(3) from a terminal thiocyanate anion, in which a chelated five-membered ring is formed by coordination of O(1) and N(1) to the Zn(1) atom. Therefore, an infinite zigzag chain consisting of Zn(II) ions and pyz anions is constructed and the chains are linked together with hydrogen bonding from coordinated and uncoordinated water molecules. The fluorescence spectra for the bridging ligand Na(pyz) and the complex were measured at room temperature in aqueous solution and in the solid state.

Synthesis, crystal structures and fluorescence of cadmium(II) coordination polymers with derivatives of pyrazine-1,4-dioxide and thiocyanate as mixed-bridging ligands

Two Cd(II) coordination polymers have been synthesized with derivatives of pyrazine-1,4-dioxide and thiocyanate anion as bridging ligands and structurally determined by X-ray crystallography. Complex 1, [Cd(μ1,3-SCN−)2(μ1,6-L1)] n (L1 = 2,5-dimethylpyrazine-1,4-dioxide), belongs to the triclinic, space group P 1 with a = 5.7627(18) Å, b = 7.182(2) Å, c = 7.509(2) Å, α = 74.042(3)°, β = 84.766(4)°, γ = 88.162(4)°; complex 2, [Cd2(μ1,3-SCN−)4(μ4-L2)] n (L2 = 2,3,5,6-tetramethylpyrazine-1,4-dioxide), crystallizes in a monoclinic system with space group C2/m with a = 10.194(4) Å, b = 13.491(6) Å, c = 8.140(3) Å, β = 120.372(4)°. Complex 1 shows a two-dimensional sheet structure, and in a direction the Cd(II) ions were coordinated by μ1,3-SCN− forming the one-dimensional chain and the L1 bridging ligand made the chains connect in the c direction leading to formation of a two-dimensional sheet on the ac plane. For 2 the one-dimensional chains in the a axis were constructed by coordination of μ1,3-SCN− bridging ligands with the Cd(II) ions, and in b and c directions the chains were joined by L2 bridging ligands leading to a three-dimensional structure. In 2 L2 displays a μ4-bridging coordination mode. Both complexes exhibit strong fluorescence emission.

Synthesis, crystal structure and fluorescence of a two-dimensional Cd(II) coordination polymer with thiocyanato and 4-methylpyridine N -oxide as bridging ligands

A two-dimensional coordination complex [Cd(μ1,3-SCN)2(μ2-mpdo)] n (mpdo = 4-methylpyridine N-oxide) has been synthesized and structurally determined by X-ray crystallography. The complex crystallizes in the triclinic space group of Pī with a = 8.2589(14) Å, b = 8.5409(14) Å, c = 9.7947(16) Å, α = 70.022(2)°, β = 74.338(2)°, γ = 71.530(2)°. Each Cd(II) is coordinated by four μ1,3-SCN− forming a zigzag chain and then two μ2-mpdo monodentate ligands coordinate to two adjacent Cd(II) ions leading to a two-dimensional sheet structure along the ab plane, and in the c direction the sheets stack parallel through π–π interactions and giving a three-dimensional structure. The complex exhibits a strong fluorescent emission spectrum in the solid state.

Synthesis and crystal structure of a 3-d polymeric cobalt(II) and sodium complex with pyrazine-2-carboxylate as a bridging ligand

A complex with a three-dimensional structure {[Na3Co(pyz)3(H2O)4(ClO4)2]} n (pyz = pyrazine-2-carboxylate anion) has been synthesized and its crystal structure determined by X-ray crystallography. The complex crystallizes in a triclinic system with a space group Pī and a = 8.598(11), b = 11.382(15), c = 14.496(19) Å, α = 87.79(2), β = 88.21(2), γ = 82.08(2)°. The Co(II) ion is located in a distorted octahedral environment with three oxygen atoms and three nitrogen atoms, from the three pyr ligands. Na(1) ion is coordinated by four oxygen atoms and two nitrogen atoms, in which O(1), O(2), O(2A), N(4A) and N(6A) come from ligand pyr while O(15) comes from H2O. Na(2) and Na(3) ions are each coordinated by six oxygen atoms. Through coordination of the bridging ligand pyr with Co(II) and Na(I) a three-dimensional net structure is formed.

Synthesis, crystal structure and magnetic property of a one-dimensional copper(II) complex with 2,5-dimethylpyrazine-1,4-dioxide as bridging ligand

A one-dimensional polynuclear copper(II) complex [Cu(μ1,6-dmpzdo)(SCN)2] n (where dmpzdo = 2,5-dimethylpyrazine-1,4-dioxide) has been synthesized and its crystal structure determined by X-ray crystallography. The coordination geometry of Cu(II) atom is a square plane and each Cu(II) ion is connected by two μ1,6-dmpzdo bridging ligands, leading to the formation of a one-dimensional chain. ESR spectra indicate magnetic coupling between the bridged Cu(II) ions. The fitting of the variable-temperature magnetic susceptibility data (4–300 K) gave 2J = −68.69 cm−1.

Synthesis, crystal structures and magnetism of lanthanide(III) binuclear complexes [Ln2(μ1 ,3-CH3CO2)2(SCN−)4L2(H2O)6] (Ln = Gd(III) and Eu(III), L = 4-methylpyridine N-oxide)

Two lanthanide(III) binuclear complexes have been synthesized with acetate as bridging ligand and 4-methylpyridine N-oxide (L), SCN− and H2O as terminal ligands and structurally determined by X-ray crystallography. Both crystals [Gd2(μ1,3-CH3CO2)2(SCN−)4(L)2(H2O6) (1) and [Eu2(μ1,3-CH3CO2)2(SCN−)4(L)2(H2O)6] (2) belong to monoclinic with space group P21/n. The relevant cell parameters are as follows: a = 9.0034(12) Å, b = 15.998(2) Å, c = 12.1277(17) Å, β = 100.625(2)° for complex 1; and a = 9.0168(18) Å, b = 15.990(3) Å, c = 12.142(2) Å, β = 100.734(3)° for complex 2; The two lanthanide(III) ions are bridged by two acetate anions forming a binuclear unit, in which L, SCN− and H2O as unidentate terminal ligands take part in the coordination. The variable-temperature magnetic susceptibility of 1 was measured in the 4–300 K range; fitting for the susceptibility data reveals that there is no magnetic interaction between the bridged Gd(III) ions.

2-Amino-3-(4-methoxy­benzyl­ideneamino)butenedinitrile

In the title compound, C12H10N4O, the structure is stabilized by an extensive network of N—H⋯N and N—H⋯O hydrogen bonds, forming columnar stacks down the c axis. As a powder, the compound exhibits second-harmonic generation efficiency.