Crystal structure of di-chlorido-1κCl,2κCl-(µ2-3,5-dimethyl-1H-pyrazolato-1κN 2:2κN 1)(3,5-dimethyl-1H-pyrazole-2κN 2){µ-2-[(2-hy-droxy-eth-yl)amino-1κ2 N,O]ethano-lato-1:2κ2 O:O}dicopper(II).

The title compound, [Cu2(C5H7N2)(C4H10NO2)Cl2(C5H8N2)], is a pyrazolate amino-alcohol complex which contains two di-methyl-pyrazole mol-ecules in monodentate and bidentate-bridged coordination modes and a monodeproton-ated di-ethano-lamine mol-ecule. Both copper atoms are involved in the formation of non-planar five-membered chelate rings. One Cu atom is in a distorted tetra-hedral environment formed by the pyridine nitro-gen atom of the protonated di-methyl-pyrazole mol-ecule, the N atom of the deprotonated bridged di-methyl-pyrazole, the Cl atom and the bridged O atom of the monodeprotonated di-ethano-lamine. The second Cu atom has an inter-mediate environment between trigonal bipyramidal and square pyramidal, formed by the N atom of the deprotonated bridged di-methyl-pyrazole, the Cl atom and the N atom of the amino-alcohol, and two O atoms of the deprotonated and protonated OH groups. In the crystal, N-H⋯Cl hydrogen bonds link the molecules into anti-symmetric chains running along the a-axis direction. Adjacent chains are connected by O-H⋯O hydrogen bonds involving the hydroxyl group as donor.

Crystal structure of poly[(µ3-4-amino-1,2,5-oxa-diazole-3-hydroxamato)thallium(I)].

The title compound represents the thallium(I) salt of a substituted 1,2,5-oxa-diazole, [Tl(C3H3N4O3)] n , with amino- and hydroxamate groups in the 4- and 3- positions of the oxa-diazole ring, respectively. In the crystal, the deprotonated hydroxamate group represents an inter-mediate between the keto/enol tautomers and forms a five-membered chelate ring with the thallium(I) cation. The coordination sphere of the cation is augmented to a distorted disphenoid by two monodentately binding O atoms from two adjacent anions, leading to the formation of zigzag chains extending parallel to the b axis. The cohesion within the chains is supported by π-π stacking [centroid-centroid distance = 3.746 (3) Å] and inter-molecular N-H⋯N hydrogen bonds.

Crystal structure and Hirshfeld surface analysis of a zinc xanthate complex containing the 2,2'-bi-pyridine ligand.

In the title compound, (2,2'-bi-pyridine-κ2 N,N')bis-(2-meth-oxy-ethyl xanthato-κS)zinc(II), [Zn(C4H7O2S2)2(C10H8N2)], the ZnII ion is coordinated to two N atoms of the 2,2'-bi-pyridine ligand and two S atoms from two 2-meth-oxy-ethyl xanthate ligands. The ZnII ion lies on a crystallographic twofold rotation axis and has distorted tetra-hedral coordination geometry. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming supramolecular chains propagating along the a-axis direction. Weak intra-molecular C-H⋯S hydrogen bonds are also observed. The inter-molecular contacts in the crystal were further analysed using Hirshfield surface analysis, which indicates that the most significant contacts are H⋯H (36.3%), followed by S⋯H/H⋯S (24.7%), C⋯H/H⋯C (15.1%), O⋯H/H⋯O (14.4%), N⋯H/H⋯N (4.1%) and C⋯C (2.9%).

Crystal structure of N-hy-droxy-quinoline-2-carboxamide monohydrate.

The title compound, C10H8N2O2·H2O, consists of an N-hy-droxy-quinoline-2-carboxamide mol-ecule in the keto tautomeric form and a water mol-ecule connected through an O-H⋯O hydrogen bond. The N-hy-droxy-quinoline-2-carboxamide mol-ecule has a nearly planar structure [maximum deviation = 0.062 (1) Å] and only the hy-droxy H atom deviates significantly from the mol-ecule plane. In the crystal, π-π stacking between the aromatic rings [inter-centroid distance = 3.887 (1) Å] and inter-molecular O-H⋯O hydrogen bonds organize the crystal components into columns extending along the b-axis direction.

Crystal structure of bis-(µ-N-hy-droxy-picolin-amid-ato)bis-[bis-(N-hy-droxy-picolinamide)-sodium].

The title compound, [Na2(C6H5N2O2)2(C6H6N2O2)4], is a centrosymmetric coordination dimer based on the sodium(I) salt of N-hy-droxy-picolinamide. The mol-ecule has an {Na2O6(µ-O)2} core with two bridging carbonyl O atoms and two hydroxamate O atoms of two mono-deprotonated residues of N-hy-droxy-picolinamide, while two neutral N-hy-droxy-picolinamide mol-ecules are coordinated in a monodentate manner to each sodium ion via the carbonyl O atoms [the Na-O distances range from 2.3044 (2) to 2.3716 (2) Å]. The penta-coordinated sodium ion exhibits a distorted trigonal-pyramidal coordination polyhedron. In the crystal, the coordination dimers are linked into chains along the c axis via N-H⋯O and N-H⋯N hydrogen bonds; the chains are linked into a two-dimensional framework parallel to (100) via weak C-H⋯O and π-π stacking inter-actions.

Crystal structure of N-hy-droxy-picolinamide monohydrate.

The crystal structure of the title compound, C6H6N2O2·H2O, consists of N-hy-droxy-picolinamide and water mol-ecules connected through O-H⋯O and N-H⋯N hydrogen bonds. The O-H⋯O inter-actions and π-π stacking inter-actions between the pyridine rings [centroid-centroid distance = 3.427 (1) Å] organize the components into columns extending along the b axis and the N-H⋯N hydrogen bonds link these columns into a two-dimensional framework parallel to (100). The N-hy-droxy-picolinamide mol-ecule adopts a strongly flattened conformation and only the O-H group H atom deviates significantly from the mol-ecule best plane. The dihedral angle between the hydroxamic group and the pyridine ring is 5.6 (2)°. The conformation about the hydroxamic group C-N bond is Z and that about the C-C bond between the pyridine and hydroxamic groups is E.

3,5-Dimethyl-4-nitroso-1H-pyrazole.

In the unit cell of the title compound, C(5)H(7)N(3)O, there are two conformers (A and B) which differ in the position of the oxime group with respect to the protonated pyrazole nitro-gen (trans in the A conformer and cis in the B conformer) and in the geometric parameters. The oxime group exists in the nitroso form in both conformers. In the crystal, mol-ecules are linked by inter-molecular N-H⋯O and N-H⋯N hydrogen bonds into zigzag-like chains along the b axis.