Jia-Geng Liu

Synthesis and Crystal Structure of a Cadmium(II) Complex with 2,2′-diamino-4,4′-bis-1,3-thiazole

Crystals of the title complex with diaminobithiazole (DABT) were obtained by a solution diffusion method. X-ray diffraction analysis shows the complex to be monoclinic, space group P21/c with cell dimensions a=11.684(2), b=13.625(2), c=14.859(1) Å and β=109.970(7)°; R=0.026. The Cd(II) atom lies in a distorted octahedral environment with two DABT and two Cl ligands in a cis arrangement. The average internal dihedral angle of 9.3° between thiazole rings of DABT shows the twisted structure of the ligand in the complex. The Cd(II) atom deviates by some -0.570 Å from the mean plane of the thiazole ring containing N(4), but the Cd-N(4) bond is the shortest among four Cd-N bonds in the structure. Intramolecular H-bonds between Cl atoms and amino groups stabilize the cis-configuration of the complex.

Separation of rosin acids by molecular recognition: crystal structure of the complex of neoabietic acid with 2-amino-6-methyl-pyridine

Neoabietic acid has been separated from gum rosin mixture by the aid of molecular recognition using 2-amino-6-methyl-pyridine as recognition reagent. The complex of neoabietic acid with 2-amino-6-methy-pyridine crystallizes from ether solution in the monoclinic, space group P21 with cell parameters of a = 7.370(1), b = 8.692(1), c = 18.365(2) Å, β = 92.53(1)°,V = 1175.3(2) Å3 and Z = 2. X-ray structure analysis shows that an extensive H-bonding network exists between neoabietic acid and amino(methyl)pyridine, which is considered as one of the factors resulting in successfully separating the neoabietic acid from the gum rosin mixture.

Separation of 4-aminobenzoic acid by cocrystallization: Crystal structure of the complex of 4-aminobenzoic acid with (2R,3R)-tartaric acid

Abstract4-Aminobenzoic acid (PABA) has been successfully separated from a mixture containing 2-aminobenzoic acid and (2R,3R)-tartaric acid. X-ray structure analysis confirms the separating result. The molecular complex formed by PABA and tartaric acid in 1:1 molar ratio crystallizes in the orthorhombic space group P212121 with cell dimensions of a = 7.329(1) Å, b = 12.095(2) Å, c = 15.231(3) Å, V = 1350.1(4) Å3, Z = 4. The crystal structure comprises protonated PABA, monoanion of tartaric acid, and crystalline water. The extensive H-bonding network exists in the crystal structure. H bonding between tartaric acid and both terminal groups on para position of PABA is considered as a possible reason for the successful separation.

Synthesis and Crystal Structure of a Polymeric Heteronuclear Complex of Cadmium(II) and Silver(I)

A polymeric complex of Cd(II) and Ag(I) bridged by thiocyanate and ethylenediamine, [Cd(en)1.5Ag(SCN)3], has been prepared and its structure determined by X-ray diffraction methods. The complex crystallizes in space group P21/n with a =7.456(1), b =9.915(2), c =19.822(2)Å, β =98.94(1)°. The Cd(II) atom is octahedrally coordinated by three SCN- anions and two en molecules, while the Ag(I) atom is tetrahedraly coordinated by four SCN- anions. Both SCN- anions and en molecules act as bridging ligands and link Ag(I) and Cd(II) atoms to form a three-dimensional polymeric structure. The distance between Ag(I) and the atom S of a 1,1,3-µ3-SCN- anion is much longer than that between Ag(I) and the atom S of a 1,3-µ-SCN- anion. The short Ag-Ag distance of 3.133 Å and small Ag-S-Ag angle of 70.92° strongly suggests the existence of an Ag-Ag bonding interaction in the complex.

Synthesis and Crystal Structure of a Cadmium Complex with Isonicotinate

The cadmium(II) complex, [Cd(iso) 2 (H 2 O) 4 ] (where iso is the anion of isonicotinic acid), has been synthesized and characterized by element analysis, thermal analysis and IR spectroscopy. An X-ray crystal structure reveals that the cadmium ion is trans -octahedral with two pyridyl nitrogens and two aqua oxygens in equational positions and two aqua oxygens in axial positions. The complex forms a three-dimensional network through intermolecular hydrogen bonds.

Synthesis and crystal structure of aqua(dimethylbithiazole)oxydiacetatonickel(II) trihydrate

The title complex, Ni(C8H8N2S2)(C4H4O5)(H2O) · 3H2O, was synthesized and its crystal structure determined by X-ray diffraction methods. Two crystallographically independent complex molecules are present in the asymmetric unit. They have similar octahedral coordination geometries, formed by a bidentate dimethylbithiazole (dMbt), a tridentate oxydiacetate dianion (ODA) and a coordinated water molecule. The tridentate ODA ligand displays an unusual facial configuration. A partially overlapped arrangement of nearly parallel dMbt ligands of neighbouring molecules is observed in the crystal, the shortest centroid distance of 3.555(3) Å between thiazole rings suggesting the existence of aromatic π–π stacking.

Synthesis and Crystal Structure of a One-Dimensional Thiocyanate-Bridged Heterometallic Complex of Copper(II) and Silver(I)

The title polymeric complex of Cu(II) and Ag(I) bridged by thiocyanate, [{Cu2(nelin)2Ag2(SCN)5} n ](SCN) n (nelin=1,9-diamino-5-methyl-5-nitro-3,7-diazanonane), has been prepared and its structure determined by X-ray diffraction methods. The complex crystallizes in space group P&1macr; with a=11.371(2), b=13.594(2), c=15.232(3)Å, α=68.50(1), β=69.18(1), γ=87.03(1)°. The Cu(II) atom is square-pyramidal, formed by one SCN- anion and one nelin ligand, while the Ag(I) atom is a tetrahedral, formed by four SCN- anions. Three different thiocyanate anions exist in the complex. Both 1,3-μ-SCN− and 1,1,3-μ-SCN− act as bridge ligands, linking Ag(I), Ag(I) atoms and Cu(II), Ag(I) atoms to form the one-dimensional polymeric structure. The coordination distance between Ag(I) and S of 1,1,3-μ-SCN− anion is apparently longer than that between Ag(I) and S of 1,3-μ-SCN− anion.

Chloro­bis(1,10-phenanthroline-κ2N,N′)copper(II) nitrate 4-nitro­benzoic acid monohydrate

In the crystal structure of the title compound, [CuCl(C12H8N2)2]NO3·C7H5NO4.H2O, the CuII ion assumes a trigonal–bipyramidal CuN4Cl coordination geometry arising from two bidentate 1,10-phenanthroline (phen) ligands and one chloride ion, with the chloride ion in an equatorial position. A partially overlapped arrangement between parallel phen rings of neighboring complexes, with face-to-face distances of 3.529 (9) and 3.452 (8) A, suggests the existence of π–π stacking.

Synthesis and Crystal Structure of the Copper Complex of bis[(2-Aminoethyl)aminomethyl] malonate

Condensation of bis(ethanediamine) copper(II) perchlorate with formaldhyde and diethyl malonate in basic methanol generates the amino acid ester complex (diethyl bis[(2-aminoethyl)aminomethyl] malonatecopper(II) perchlorate), [Cu(L1)](ClO4)2. Base-catalyzed ester hydrolysis in water of [Cu(L1)]2+ yields bis[(2-aminoethyl)aminomethyl] malonatocopper(II) tetrahydrate, CuL2 · 4 H2O. The two copper(II) complexes were characterized by element analysis, molar conductance, infrared, and electronic spectra studies. The structure of CuL2 · 4 H2O was determined by X-ray diffraction (XRD). The crystal structure reveals that the copper ion is an octahedra with four nitrogens at the equational position and two oxygens at the axial positions.