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. the imine and the other pyridyl [Hg-N = 2.467 (6) and 2.310 (6) Å, respectively] belonging to the bidentate imino-pyridine ligand, and three Cl atoms [Hg-Cl = 2.407 (2), 2.447 (2) and 3.031 (2) Å]. The longest Hg-Cl bond is bridging about the inversion centre. In the ligand, the central ring and pyridine ring are oriented at a dihedral angle of 8.1 (4)°, while the planes of the pyridine ring and the terminal phenyl ring are oriented at a dihedral angle of 53.8 (4)°. In the crystal, mol-ecules are linked by N-H⋯Cl and C-H⋯Cl hydrogen bonds, forming sheets parallel to (001).

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. the quinolyl and the imine N atom [Hg-N = 2.270 (4) and 2.346 (4) Å, respectively]. The dihedral angle between the two benzene rings attached to the amino group is 43.7 (3)°. In the crystal, N-H⋯Cl and C-H⋯Cl hydrogen bonds, as well as π-π stacking inter-actions between one phenyl ring and the pyridine ring of the quinoline moiety of an adjacent mol-ecule [centroid-to-centroid separation = 3.617 (4) Å] are observed, resulting in a three-dimensional network.

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. deviation = 0.027 Å) and the terminal N-phenyl ring are 29.34 (4) and 43.43 (7)°, respectively. The conformation about the C=N bond is E. In the crystal, mol-ecules are linked by N-H⋯π and C-H⋯π inter-actions forming chains propagating along the [10-2] direction. These chains are linked via π-π inter-actions [inter-centroid distances are in the range 3.5569 (11)-3.708 (1) Å], forming slabs lying parallel to (30-4).

(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. One of the water mol-ecules lies on an inversion centre, so that its H atoms are disordered over two sites. The coordination environment of Ni(II) has a slightly distorted octa-hedral geometry, which is formed by one O and five N atoms belonging to the N,O-chelating pyrazol-1-ide-5-carboxyl-ate and two N,N'-chelating phenanthroline mol-ecules. In the crystal, O-H⋯O, N-H⋯O and O-H⋯N hydrogen bonds involving the solvent water mol-ecules and pyrazole-5-carboxyl-ate ligands form layers parallel to the ab plane. These layers are linked further via weak π-π inter-actions between two adjacent phenanthroline mol-ecules, with centroid-to-centroid distances in the range 3.886 (2)-4.018 (1) Å, together with C-H⋯π contacts, forming a three-dimensional network.

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. The structure exhibits π-π inter-actions between pyridine rings [centroid-centroid distances = 3.7267 (2), 3.7811 (2) and 3.8924 (2) Å]. The N atom and a neighboring C atom of the pyridinium cation are statistically disordered with an occupancy ratio of 0.58 (2):0.42 (2).

(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.

cis-Bis(2,2'-bipyridine-κN,N')bis-(dimethyl sulfoxide-κO)zinc bis-(tetra-phenyl-borate) dimethyl sulfoxide monosolvate.

In the mononuclear title complex, [Zn(C(10)H(8)N(2))(2)(C(2)H(6)OS)(2)](C(24)H(20)B)(2)·C(2)H(6)OS, the Zn(II) ion is coordinated by four N atoms of two bidentate 2,2'-bipyridine mol-ecules and by the O atoms of two cis-disposed dimethyl sulfoxide mol-ecules in a distorted octa-hedral geometry. The S atom and the methyl groups of one of the coordinated dimethyl sulfoxide mol-ecules are disordered in a 0.509 (2):0.491 (2) ratio. The crystal packing is stabilized by C-H⋯O hydrogen bonds between the dimethyl sulfoxide solvent mol-ecules and tetra-phenyl-borate anions.

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. O-H⋯O hydrogen bonds are formed between the water mol-ecules and the carboxyl-ate O atoms.

(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 89.41 (5)°. The methyl group is in a trans position with respect to the pyridine N atom. In the crystal, the mol-ecules are arranged in zigzag layers parallel to the b axis. The mol-ecules within the layers are inter-connected by strong O-H⋯N and weak N-H⋯O hydrogen bonds; the former take place between OH groups and amine N atoms and the latter between the amine N atom and the carbonyl O atom. In addition, C-H⋯O inter-actions are also present.

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. Bond lengths and angles are similar to those in related compounds.

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)°. The oxime group is in an E position with respect to the -OH group and forms an intra-molecular O-H⋯N hydrogen bond. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link mol-ecules into chains propagating along [001]. The crystal structure is further stabilized by inter-molecular stacking inter-actions between the rings [centroid-to-centroid distance = 3.93 (1) Å], resulting in layers parallel to the bc plane.