Crystal structure of di-μ-chlorido-bis(chlorido-{N (1)-phenyl-N (4)-[(pyridin-2-yl-κN)methyl-idene]benzene-1,4-di-amine-κN (4)}mercury(II)).

The whole mol-ecule of the title complex, [Hg2Cl4(C18H15N3)2], is generated by inversion symmetry. It was synthesized from the pyridine-derived Schiff base N-phenyl-N'-[(pyridin-2-yl)methyl-idene]benzene-1,4-di-amine (PPMBD). The five-coordinated Hg(2+) ions have a distorted square-pyramidal environment defined by two N atoms, viz.

Crystal structure of di-chlorido-{N (1)-phenyl-N (4)-[(quinolin-2-yl-κN)methylidene]benzene-1,4-diamine-κN (4)}mercury(II).

In the mononuclear title complex, [HgCl2(C22H17N3)], synthesized from the quinoline-derived Schiff base N (1)-phenyl-N (4)-[(quinolin-2-yl)methyl-idene]benzene-1,4-di-amine (PQMBD) and HgCl2, the coordination sphere around the Hg(2+) atom is distorted tetra-hedral, comprising two Cl atoms [Hg-Cl = 2.3487 (14) and 2.4490 (15) Å] and two N atom donors from the PQMBD ligand, viz.

Crystal structure of N (1)-phenyl-N (4)-[(E)-(pyren-1-yl)methyl-idene]benzene-1,4-di-amine.

In the title compound, C29H20N2, the dihedral angles subtended by the central p-phenyl-enedi-amine ring with respect to the mean plane of the terminal pyrenyl ring system (r.m.s.

(3-Acetyl-4-methyl-1H-pyrazol-1-ide-5-carboxyl-ato)bis-(1,10-phenanthroline)nickel(II) 3.5-hydrate.

The title compound, [Ni(C7H6N2O3)(C12H8N2)2]·3.5H2O, crystallizes as a neutral mononuclear complex with 3.5 solvent water mol-ecules.

Pyridinium bis-(pyridine-κN)tetra-kis-(thio-cyanato-κN)ferrate(III).

In the title compound, (C5H6N)[Fe(NCS)4(C5H5N)2], the Fe(III) ion is coordinated by four thio-cyanate N atoms and two pyridine N atoms in a trans arrangement, forming an FeN6 polyhedron with a slightly distorted octa-hedral geometry. Charge balance is achieved by one pyridinium cation bound to the complex anion via N-H⋯S hydrogen bonding. The asymmetric unit consists of one Fe(III) cation, four thio-cyanate anions, two coordinated pyridine mol-ecules and one pyridinium cation.

(3-Acetyl-5-carboxyl-ato-4-methyl-1H-pyrazol-1-ido-κ(2) N (1),O (5))aqua-[(pyridin-2-yl)methanamine-κ(2) N,N']copper(II).

In the title compound, [Cu(C7H6N2O3)(C6H8N2)(H2O)], the Cu(II) ion is in a distorted square-pyramidal N3O2 environment formed by two bidentate chelating ligands in the equatorial coordination sites and one water mol-ecule in the apical direction. In the crystal, O-H⋯O, N-H⋯O and O-H⋯N hydrogen bonds link the complex mol-ecules into a three-dimensional supra-molecular network.

Poly[di-μ(2)-aqua-μ(5)-(pyridine-2,6-dicarboxyl-ato)-μ(3)-(pyridine-2,6-dicarboxyl-ato)-cobalt(II)disodium].

In the title compound, [CoNa(2)(C(7)H(3)NO(4))(2)(H(2)O)(2)](n), the Co(II) atom is coordinated by two pyridine N atoms and four carboxyl-ate O atoms from two doubly deprotonated pyridine-2,6-dicarboxyl-ate ligands in a distorted octa-hedral geometry. One Na(+) cation is coordinated by three carboxyl-ate O atoms and two water mol-ecules and the other is coordinated by five carboxyl-ate O atoms and two water mol-ecules in an irregular geometry. The bis-(pyridine-2,6-dicarboxyl-ato)cobalt complex units are connected by Na(+) cations and bridging water mol-ecules into a three-dimensional coordination network.

2,2'-Dihydroxybiphenyl-3,3'-di-carb-aldehyde dioxime.

The mol-ecule of the title compound, C(14)H(12)N(2)O(4), lies across a crystallographic inversion centre situated at the mid-point of the C-C intra-annular bond. The mol-ecule is not planar, the dihedral angle between the aromatic rings being 50.1 (1)°.

Potassium 2-(N-hydroxy-carbamo-yl)acetate monohydrate.

The crystal structure of the title compound, K(+)·C(3)H(4)NO(4) (-)·H(2)O, consists of potassium cations, monoanions of 2-carboxy-acetohydroxamic acid [namely 2-(N-hydroxy-carbamo-yl)acetate] and solvent water mol-ecules. The elements of the structure are united in a three-dimensional network by numerous K⋯O coordinate bonds and O-H⋯O and N-H⋯O hydrogen bonds. The coordination sphere of the K(+) ions may be described as a distorted double capped octa-hedron.

(2RS)-3-Hydr-oxy-2-methyl-2-(2-pyrid-yl)imidazolidine-4-one.

The title structure, C(9)H(11)N(3)O(2), is a racemate. The chiral centre is situated at the N-C-N C atom of the imidazolidine ring. The inter-planar angle between the mean planes of the pyridine and imidazolidine rings is 89.