Lian-Dong Liu

Syntheses, crystal structures and magnetic study of two binuclear manganese(II) complexes with aromatic N-oxide as bridging ligand

Two new binuclear complexes, [Mn2(μ-dmpo)2(SCN)4(H2O)2] (1) (where dmpo = 3,5-dimethylpyridine N-oxide), [Mn2(μ-po)2(H2O)6I2]I2 (2) (where po = pyridine N-oxide), have been synthesized and their crystal structures determined by X-ray crystallography. Complexes 1 and 2 crystallize in monoclinic, space group P21/c, with unit cell dimensions a = 8.8836(18) Å, b = 15.450(3) Å, c = 15.484(3) Å, β = 91.020(3)° for 1, and a = 8.8352(13) Å, b = 17.927(3) Å, c = 8.3338(12) Å, β = 103.765(2)° for 2. In each binuclear complex two Mn(II) were bridged by two 3,5-dimethylpyridine N-oxides or by two pyridine N-oxides and the distances between the bridged Mn(II) ions are 3.599 Å for 1 and 3.552 Å for 2. Variable temperature (4–300 K) magnetic measurements were performed for 1 and the susceptibility data were fitted by using a binuclear Mn(II) magnetic coupling formula producing the 2J = −2.17 cm−1.

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.

(3R,6R,12R,20S,24S)-20,24-Ep-oxy-dammarane-3,6,12,25-tetraol dihydrate.

The title compound, C30H52O5·2H2O, was degraded from pseudoginsenoside F11 which was extracted and seperated from Panax quinquefolium saponin. The three six-membered rings are in chair conformations. The five-membered ring is in an envelope conformation and the tetrahydrofuran ring has a conformation intermediate between half-chair and envelope. In the crystal, intermolecular O—H⋯O hydrogen bonds link molecules into a three-dimensional network. Intramolecular O—H⋯O hydrogen bonds also occur.

Poly[[{μ3-1,2-bis­[(3-cyano­benzyl­idene)­hydrazono]-1,2-diphenyl­ethane}silver(I)] hexa­fluoridoantimonate]

In the title compound, {[Ag(C30H20N6)][SbF6]}n, the Ag+ cation has a three-coordinate environment completed by three N atoms of the 1,2-bis[(3-cyanobenzylidene)hydrazono]-1,2-diphenylethane ligand. The Ag+ cation coordination geometry is best described as distorted T-shaped. The crystal structure forms a three-dimensional structural polymer.

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.

Crystal structure of 4-((E)-((E)-5-(2-fluorobenzylidene)-1-((4-fluorophenyl)sulfonyl)-4-oxopiperidin-3-ylidene)methyl)benzonitrile, C26H18F2N2O3S

Abstract C26H18F2N2O3S, monoclinic, P21/c (no. 14), a = 8.412(3) Å, b = 22.056(8) Å, c = 12.125(4) Å, β = 102.316(5)°, V = 2198.0(14) Å3, Z = 4, Rgt(F) = 0.0475, wRref(F2) = 0.1156, T = 173(2) K.

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.