Structure cristalline du bis(hydrogéno pyridine-2,6-dicarboxylato)nickel(II) trihydraté

Abstract

Nickel bis(hydrogen pyridine-2,6-dicarboxylate) trihydrate, Ni(HDP)z.3H20, crystallizes in the monoclinic system, space group P21/c, with a=14.76+0.10, b= 10.05+0.02, c=13.76+0.08 ~, ,/3= 122.2+0.4 °, Z=4. The structure was determined by means of the Patterson function and Fourier syntheses which were calculated from intensities collected on Weissenberg equi-inclination photographs using Cu Ko~ radiation. Prior to the structure refinement, the atoms were divided into two blocks, and anisotropic full-matrix least-squares calculations were successively applied to each (R= 0.087). The Ni atom is surrounded by an unsymmetrical arrangement of the two nitrogen atoms and also four oxygen atoms, each of which belongs to a different carboxylic or carboxylato group. The chelate molecule is thus formed of two orthogonal HDP planes, and the three water molecules are in interstitial positions.

Metal-Mediated Pseudo Coordination Isomerism in Complexes of Mixed Neutral Didentate and Dianionic Tridentate Pyridine-Containing Ligands

“…Both effects reflect the small bite angle of the tridentate ligand 2 for the relatively large nickel(ii) ion. The previously reported [Ni(Hdipic) 2 ] · 3H 2 O complex exhibits almost regular octahedral geometry, [4,5] with Ni O distances in the range 2.10-2.21 Å, the longer distances associated with the protonated acid group; the Ni O(carboxylate) distances are comparable to those observed here, as are Ni N distances.…”

“…The coordination chemistry of both has been widely examined, [2] yet few complexes of the two in concert have been reported. For example, structural studies of bis(dipic) complexes of both copper(ii) and nickel(ii) have appeared, [3][4][5] and a range of structures of bis(ampy)copper(ii) complexes with various counter ions are known. [6][7][8][9] Of particular relevance to this work is a study of the solution thermodynamics of Co(ii), Ni(ii), and Cu(ii) reacting with mixtures of dipic and en (ethane-1,2-diamine).…”

Structure cristalline du tri-μ-hydroxo-tri(pyridine-2 carboxylato)tribéryllium monohydraté, [Be3(OH)3(C5H4NCOO)3].H2O. Mise en evidence d'un cycle béryllium–oxygène d'ordre 6

“…ORSAY (CIRCE) par l'interm6diaire du terminal de rInstitut de Recherche sur la catalyse 5. Lyon, ~t l'aide d'une biblioth6que de programmes existant au laboratoire et pr6c6demment indiqu6e (Quaglieri, Loiseleur & Thomas, 1972).…”

tert-Butyl-6 méthyl-2 hexahydro-2,3,5,6,7,8 4H-benzo[b]pyrannone-4-cis, C14H22O2

“…Iterations finales sur les x, y, z de tous les atomes et les flij des atomes de carbone et d'oxyg6ne; R = 0,063, wR = 0,096 avec w = (a+blFol)-2; S = 0,72; (ZI/O')max = 0,80 (atomes non hydrog+ne); s~rie-diff6rence finale: zip < 0,12 e A -3. f pris dans International Tables for X-ray Crystallography (1974). Calculs effectu~s ~ l'aide de notre biblioth+que classique de programmes (Quaglieri, Loiseleur & Thomas, 1972).…”