Zheng Xu

Transition metal complexes of the Schiff bases derived from S-alkyldithiocarbazate with 2-pyridinecarboxaldehyde N-oxide—I. Synthesis, properties and structure of four-coordinate copper(II) complexes

Abstract Two new Schiff bases (SMPDH and SBPDH) of S-methyl- and S-benzyl-dithiocarbazate with 2-pyridinecarboxaldehyde N-oxide were prepared and confirmed by elemental analyses and IR spectra. Four copper(II) complexes of the above two Schiff base ligands with imidazole and pyridine were obtained and characterized spectroscopically. The crystal structure of [Cu(SMPD)ImH]ClO4 was determined by X-ray diffraction analysis. The geometry of the copper atoms in these complexes is square planar with an unsymmetrical environment.

Crystal structure and mass spectra of a copper(I) complex with a chain arrangement: [μ-4,4′-bipy-Cu(TTA)]n

Abstract The first chain copper(I) complex with 4,4′-bipyridine as the bridging ligand, of the formula [μ-4,4′-bipy-Cu(TTA)]n (TTA = 2-thienoyltrifluoroacetone), has been prepared and characterized by elemental analysis, IR and FAB mass spectra. Its X-ray crystal structure determination reveals that the local coordination geometry around copper(I) is a distorted tetrahedron. Cu(TTA) units are bridged by 4,4′-bipyridine to form an infinite zigzag chain with an Nue5f8Cuue5f9N angle of 143.3(7)°. The short Cuue5f8N distance (1.98 A) indicates that quite strong molecular chains have been formed in the crystal.

Synthesis and characterization of binuclear organolanthanide complexes involving cyclopentadienyl and n-propyloxide ligands. X-ray crystal structure of [(C5H5)2Yb(μ-OCH2CH2CH3)]2

By the reaction of Cp3Ln (Cp = C5H5; Ln = Dy, Ho, Yb) with equimolar n-propyl alcohol in THF (tetrahydrofuran) at room temperature three new binuclear organolanthanide complexes, [CP2Ln(mu-OCH2CH2CH3)]2 (Ln = Dy, Ho, Yb), have been synthesized, as shown by X-ray single-crystal structure analysis for the complex [Cp2Yb(mu-OCH2CH2CH3)]2. All the complexes were characterized by elemental analysis, IR and MS spectra. The Yb2O2 unit is planar, and the ytterbium atom is coordinated by two Cp ring centroids and two oxygen atoms of two n-propyloxide ligands to form a distorted tetrahedral geometry. The average Yb-C (Cp) bond distance is 2.589(17) angstrom. The average Yb-O distance is 2.199(5) angstrom. The Yb-Yb separation [3.521(1) angstrom] indicates that no metal-metal interaction is present.

Formation and crystal structures of (C5H5)3Sm(THF) and (C5H5)3Dy(THF)

Abstract The title complexes were formed by refluxing the complexes [Cp2SmO(CH2)4CH3]2 and [Cp2DyS(CH2)3CH3]2 (Cp ue5fb C5H5) in THF and studied by X-ray crystallography. The complexes are both monomers with the central metal coordinated by three Cp ring centroids and one THF molecule to form a distorted tetrahedral geometry. The Cp groups coordinate to the metal in a η5-fashion with the average Smue5f8C distance of 2.75(2) A and Dyue5f8C distance of 2.70(1) A. The Smue5f8O and Dyue5f8O bond lengths are 2.512(8) and 2.462(6) A, respectively. The comparison of some significant structural parameters of the title complexes with those of the known isostructural complexes Cp3Ln·THF (Ln ue5fb La, Pr, Nd, Gd and Lu) conformed to the “lanthanide contration” effect.

Synthesis, crystal structure and magnetic properties of oxo-bridged binuclear iron(III) complex [Fe(phen)2PhCOO]2OCl2·7H2O

Abstract An oxo-bridged binuclear iron(III) complex, [Fe(phen) 2 PhCOO] 2 OCl 2 ·7H 2 O, was synthesized and the crystal structure indicated that two octahedrally coordinated iron(III) ions bridged with oxygen atoms formed a non-linear complex. The bond angle of Feue5f8Oue5f8Fe is 155.6°. The studies of magnetic properties showed that there was strong antiferromagnetic superexchange coupling ( J = −80.8 cm − ) between two S = 5 2 iron(III) ions.

Transition metal complexes of the schiff bases derived from S-alkyldithiocarbazate with 2-pyridinecarboxaldehyde N-oxide—II. Syntheses, properties and X-ray crystal structure of five-coordinate copper(II) complexes

Abstract Four five-coordinate copper(II) complexes of deprotonated S-R-β-N-(pyridine N-oxide-2-ylmethylidene)dithiocarbazates (R = methyl, abbreviated SMPDH; R = benzyl, abbreviated SBPDH) with o-phenanthroline or 2,2′-bipyridine, were synthesized and characterized by UV, IR spectra and magnetic susceptibilities at room temperature. The X-ray crystal structure of [Cu(SBPD)Phen]ClO4, was determined. The crystal structure contains a mononuclear unit in which copper(II) displays a distorted square pyramidal geometry.

Crystal structure of (cyclopentadienyl)-dichlorogadolinium(III)-tris(tetrahydrofuran)

Abstract The compound CpGdCl2-3THF has been successfully prepared from NaCp (Cp = C5H5) and GdCl3 (2:1 molar ratio) in THF and characterized by elemental analysis, IR and MS spectra and a single crystal X-ray diffraction study, showing that the compound is monomeric in both vapour and solid states. Crystals are monoclinic, space group P21/n, with a = 7.818, b = 17.139(2), c = 15.203(2)A, β = 95.88(2)°, and D c=1.678 g/cm3 for Z=4; 1876 reflections were considered observed. The structure was solved by heavy-atom methods. Least-squares refinement converged to a final value of R=0.041. The gadolinium has a distorted octahedral geometry coordinated by one Cp ring centroid, three THF oxygen atoms and two chloride anions. The average Gd-O(THF) distance is 2.397(3) A. The Gd-C(Cp) bond lengths range from 2.673(6) to 2.691(6)A, and average 2.683(6)A.

Preparation and x-ray crystal structure of deprotonated S-methyl-β-N-(pyridine N-oxide-2-ylmethylidene)dithiocarbazate pyridine nickel(II) perchlorate: [Ni(C8H8N3OS2)(C5H5N)]ClO4

Abstract A nickel(II) complex with S-methyl-β-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate (LH) and pyridine (Py) as ligands with the formula [NiLPy]ClO4 has been synthesized. The crystal structure has been determined by X-ray diffraction analysis. Sulphur, nitrogen and oxygen atoms of the tridentate ligand, as well as a nitrogen atom of one additive pyridine, adopt a planar conformation to produce the square planar geometry at each nickel atom. Magnetic susceptibility and IR spectra are interpreted in accordance with the proposed stereochemistry.

X-RAY CRYSTAL STRUCTURE, SPECTRAL AND MAGNETIC PROPERTIES OF A MIXED-LIGAND DINUCLEAR COMPLEX CU(PHEN)(SA)(CLO4)2

Abstract The mixed-ligand dinuclear complex [Cu(Phen)(Sa)(ClO4)]2 (where Phen = 1,10-phenanthroline and Sa = salicylaldehyde) has been synthesized and characterized by IR and ESR spectra and magnetic susceptibility measurements, which obey the Curie-Weiss law with θ = −10 K. The crystal structure of the title complex has been determined and is a dimer in which two monomeric units are bridged by two oxygen atoms of phenolate groups.

Synthesis and structure of monocyclopentadienylyttrium(III) dichloride tris(tetrahydrofuran)

Abstract The complex CpYCl2(THF)3 (Cp ue5fb C5H5) was obtained by reacting YCl3 with sodium and cyclopentadiene (1:1:5 molar ratio) in THF at room temperature, which has been studied by X-ray crystallography. The complex is monomeric with the ytrium atom coordinated by one Cp ring centroid, three oxygen atoms from three THF molcecules and two chloride atoms to give rise to a distorted octahedral coordination. The Yue5f8C(Cp) bond lengths range from 2.59(3) to 2.73(4) A and average 2.65(3) A. The THF molecules coordinate to the yttrium atom with Yue5f8O distances of 2.34(2), 2.35(2), 2.35(2) and 2.50(2) A, respectively. The Yue5f8Cl bond lengths are 2.630(8) and 2.625(7) A, respectively. Some significant parameters of the title complex have been compared with the corresponding values of the known isostructural organolanthanide complexes of Nd, Gd, Ho, Er and Yb.