Polymeric aqua(glutarato)(hydrogen glutarato)lanthanum(III) monohydrate

The structure of the title compound, [La(C5H6O4)(C5H7O4)(H2O)] . H2O, consists of dense layers formed by chains of one-edge-sharing LaO9 (H2O) polyhedra, linked together by the glutarate ligand. The three-dimensional polymeric structure, built up through connection of these layers by the hydrogen glutarate ligand, exhibits cavities accommodating a guest water molecule. The lanthanum ion is tenfold coordinated by four glutarates, acting as bridging-chelating carboxylate groups, by three hydrogen glutarates, three times monodentate, and by one water molecule. Its coordination polyhedron is highly distorted and intermediate between a bicapped dodecahedron and a tetracapped trigonal prism. Hydrogen bonding links the two water molecules and the framework built up from this polynuclear coordination polymer. A very short hydrogen bond, D ... A = 2.484 (3) Angstrom, links the protonated with the deprotonated acid groups in the hydrogen glutarate. [References: 12] 1

Intra- and supra­molecular inter­actions in cis,mer-diaqua­tris­(1H-imidazole-κN 3)(terephthalato-κO)cobalt(II) monohydrate

In the title compound, [Co(C8H4O4)(C3H4N2)3(H2O)2]·H2O, the cisoid angles are in the range 85.59 (5)–93.56 (5)°, while two equal transoid angles deviate significantly from the ideal linear angle, the third being almost linear. One carboxyl­ate group is almost coplanar [1.23 (13)°] with the plane of its parent aromatic ring, although it has one O-atom donor involved in one coordination and one hydrogen bond as acceptor. The other carboxyl­ate group does not coordinate and is rotated out of this plane with a torsional twist of 17.27 (20)°. The coordination neutral entity, based on aqua ligands and two cyclic co-ligands seems, at first sight, monomeric. Strongly tight, via one intra­molecular hydrogen bond between aqua and carboxyl­ate O atoms, it brings out a quasi-planar six-membered ring around the CoII atom, turning the CoN3O3 coordination octa­hedron into a new building block. The rigidity of this feature associated with several hydrogen-bonded arrays yields an extended structure. In the resulting supra­molecular packing, a binuclear hydrated CoII assembly, built up from triple strands driven by different heterosynthons, embodies the synergy of coordination, covalent and hydrogen bonds

Spectrometric Analyses, Structure and Voltammetric Study of Nickel(II) with N[(1E) Phenylmethylene N2[2(2Hydroxyphenylmethylene]Amino ethyl) Imidazolidin-1-yl Ethylamine

The reaction of N[(1E) phenylmethylene N2[2(2hydroxyphenylmethylene]amino ethyl) imidazolidin -1-yl ethylamine ligand (H 3 L) with nickel(II) salt, by heating at 40°C and addition of NaOH in excess, was made by eliminating of the phenol substituted imidazolidine ring, giving the mononuclear nickel(II) complex of the deprotonated bis-salicylaldehyde-triethylenetetramine (L −2 ). UV-Vis, FTIR and structural resolution show an octahedral geometry for [NiL]·6H 2 O complex. This compound has been characterized by single crystal X-ray diffraction study. This technique reveals that Ni-H 2 L involves a high-spin nickel(II) ion within a pseudo-octahedral geometry. The Ni(II) complex has NiN 4 O 2 coordination sphere as established from a crystal structure determination. The crystals of Ni(II) complex are tetragonal, space group P4/ncc, a = b = 19.348 A; c = 13.201 A. R(F) value (0.0528) found shows a very good precision of the determined geometrical parameters. Cyclic voltammetry of nickel complex is indicative of electronic communication between the nickel center via Schiff base ligand. The results obtained confirm the imidazolidine ring-cleavage reaction and the elimination of the substituted phenol on this ring and show that the presence of H 3 L ligand around the metallic center stabilizes the oxidation of the Ni(II) to Ni(III)

Cristallochimie et reactivite de complexes de metaux de transition avec des phosphines fonctionnalisees

SIGLEINIST T 74661 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Synthesis and Reactions of Pyranobenzimidazole-2-thiones from Dehydroacetic Acid

International audienceAn efficient synthesis of pyranobenzimidazole-2-thiones has been described through reaction of carbon disulfide or thiophosgene with enaminone. The alkylation of pyranobenzimidazole-2-thione in the presence of methyl iodide furnished the desired S-methylated derivatives, and the reaction of pyranobenzimidazole-2-thione with copper (I) iodide and triphenylphosphine gave a dimeric complex [Cu (PPh3) (bzimtH)](2)