ABSTRACT
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-Hâ¯O and N-Hâ¯N hydrogen bonds into zigzag-like chains along the b axis.
ABSTRACT
In the neutral, mononuclear title complex, [Ni(C(4)H(6)NO(3))(2)(H(2)O)(2)], the Ni atom lies on a crystallographic inversion centre within a distorted octa-hedral N(2)O(4) environment. Two trans-disposed anions of 3-hydroxy-imino-butanoic acid occupy four equatorial sites, coordinated by the deprotonated carboxyl-ate and protonated oxime groups and forming six-membered chelate rings, while the two axial positions are occupied by the water O atoms. The O atom of the oxime group forms an intra-molecular hydrogen bond with the coordinated carboxyl-ate O atom. The complex mol-ecules are linked into chains along b by hydrogen bonds between the water O atom and the carboxyl-ate O of a neighbouring mol-ecule. The chains are linked by further hydrogen bonds into a layer structure.
ABSTRACT
The title centrosymmetric mononuclear complex, [Ni(C(4)H(6)NO(3))(2)(H(2)O)(2)], is a polymorph of the previously reported complex [Dudarenko et al. (2010 â¶). Acta Cryst. E66, m277-m278]. The Ni(II) atom, lying on an inversion center, is six-coordinated by two carboxyl-ate O atoms and two oxime N atoms from two trans-disposed chelating 3-hydroxy-imino-butanoate ligands and two axial water mol-ecules in a distorted octa-hedral geometry. The hydr-oxy group forms an intra-molecular hydrogen bond with the coordinated carboxyl-ate O atom. The complex mol-ecules are linked in stacks along [010] by a hydrogen bond between the water O atom and the carboxyl-ate O atom of a neighboring mol-ecule. The stacks are further linked by O-Hâ¯O hydrogen bonds into a layer parallel to (001).
ABSTRACT
The cation of the title salt, C(7)H(16)N(3)O(3) (+)·C(3)H(4)NO(3) (-), the oxime group is trans with respect to the amide-carbonyl group. The components of the structure are united into a three-dimensional network by an extensive system of O-Hâ¯O and N-Hâ¯O hydrogen bonds.
ABSTRACT
The title compound, (C2H10N2)2[Ni(C2HN2O4)2].2H2O, has an ionic structure containing a centrosymmetric complex 4- anion, charge-balancing ethylenediaminium dications and solvent water molecules. The oxalohydroxamate unit is triply deprotonated and forms five-membered chelate rings with the central Ni ion; the Ni ion lies on an inversion centre. The two hydroxamate O atoms in the complex anion are linked by short intramolecular hydrogen bonds.
