(2E)-2-Hydroxy­imino-N′-[(E)-2-pyridyl­methyl­ene]propanohydrazide

In the title compound, C9H10N4O2, the pyridine ring is twisted by 16.5 (1)° from the mean plane defined by the remaining non-H atoms. An intra­molecular N—H⋯N inter­action is present. In the crystal, inter­molecular O—H⋯N and N—H⋯O hydrogen bonds link mol­ecules into layers parallel to the bc plane. The crystal packing exhibits π–π inter­actions indicated by the short distance of 3.649 (1) Å between the centroids of the pyridine rings of neighbouring mol­ecules

Poly[bis­[μ4-N-(2-hydroxy­imino­propion­yl)-N′-(2-oxidoimino­propion­yl)propane-1,3-diaminato]dimethano­lcalciumdicopper(II)]

In the title compound, [CaCu2(C9H13N4O4)2(CH3OH)2]n, the CaII atom lies on an inversion center and is situated in a moderately distorted octa­hedral environment. The CuII atom is in a distorted square-pyramidal geometry, defined by four N atoms belonging to the amide and oxime groups of the triply deprotonated residue of N,N′-bis­(2-hydroxy­imino­propano­yl)propane-1,3-diamine (H4pap) and one oxime O atom from a neighboring Hpap ligand at the apical site, forming a dimeric [Cu2(Hpap)2]2− unit. Each dimeric unit connects four Ca atoms and each Ca atom links four [Cu2(Hpap)2]2− units through Ca—O(amide) bonds, leading to a three-dimensional framework. The crystal structure involves intra- and inter­molecular O—H⋯O hydrogen bonds

N-(2-Hydroxy­ethyl)-2-[2-(hydroxy­imino)propanamido]ethanaminium 2-(hydroxy­imino)propanoate

The cation of the title salt, C7H16N3O3 +·C3H4NO3 −, 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—H⋯O and N—H⋯O hydrogen bonds

Diaquabis­[3-(hydroxy­imino)­butanoato]nickel(II)

In the neutral, mononuclear title complex, [Ni(C4H6NO3)2(H2O)2], the Ni atom lies on a crystallographic inversion centre within a distorted octa­hedral N2O4 environment. Two trans-disposed anions of 3-hydroxy­imino­butanoic acid occupy four equatorial sites, coordinated by the deprotonated carboxyl­ate 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 intra­molecular hydrogen bond with the coordinated carboxyl­ate O atom. The complex mol­ecules are linked into chains along b by hydrogen bonds between the water O atom and the carboxyl­ate O of a neighbouring mol­ecule. The chains are linked by further hydrogen bonds into a layer structure

Diaquabis­[3-(hydroxy­imino­)butanoato]nickel(II): a triclinic polymorph

The title centrosymmetric mononuclear complex, [Ni(C4H6NO3)2(H2O)2], is a polymorph of the previously reported complex [Dudarenko et al. (2010 ▶). Acta Cryst. E66, m277–m278]. The NiII atom, lying on an inversion center, is six-coordinated by two carboxyl­ate O atoms and two oxime N atoms from two trans-disposed chelating 3-hydroxy­imino­butanoate ligands and two axial water mol­ecules in a distorted octa­hedral geometry. The hydr­oxy group forms an intra­molecular hydrogen bond with the coordinated carboxyl­ate O atom. The complex mol­ecules are linked in stacks along [010] by a hydrogen bond between the water O atom and the carboxyl­ate O atom of a neighboring mol­ecule. The stacks are further linked by O—H⋯O hydrogen bonds into a layer parallel to (001)

μ-Peroxido-bis­[acetonitrile­bis­(ethyl­enediamine)­cobalt(III)] tetrakis(per­chlorate)

The title compound, [Co2(O2)(CH3CN)2(C2H8N2)4](ClO4)4, consists of centrosymmetric binuclear cations and perchlorate anions. Two CoIII atoms, which have a slightly distorted octa­hedral coordination, are connected through a peroxido bridge; the O—O distance is 1.476 (3) Å. Both acetonitrile ligands are situated in a trans position with respect to the O—O bridge. In the crystal, the complex cations are connected by N—H⋯O hydrogen bonds between ethyl­endiamine NH groups and O atoms from the perchlorate anions and peroxide O atoms

Diaqua­bis­(pyridine-2-carboxyl­ato-κ2 N,O)manganese(II) dimethyl­formamide hemisolvate

There are two crystallographically independent complex mol­ecules with very similar geometries in the unit cell of the title compound, [Mn(C6H4NO2)2(H2O)2]·0.5C3H7NO. The central ion is situated in a distorted octa­hedral environment of two N- and four O-donor atoms from two pyridine-2-carboxyl­ate ligands and two cis-disposed water mol­ecules. The carboxyl­ate ligands are coordinated in a chelate fashion with the formation of two five-membered rings. In the crystal, the complex mol­ecules are connected by O—H⋯O hydrogen bonds between the coordinated water mol­ecules and the uncoordinated carboxyl­ate O atoms, thus forming hydrogen-bonded walls disposed perpendicularly to the bc plane

fac-Tris(pyridine-2-carboxyl­ato-κ2 N,O)cobalt(III)

In the title compound, [Co(C6H4NO2)3], the CoIII ion lies on a threefold rotation axis and is in a distorted octa­hedral environment defined by three N and three O donor atoms from three fac-disposed pyridine-2-carboxyl­ate ligands. The ligands are coordinated in a chelate fashion, forming three five-membered rings. In the crystal, translationally related complex molecules are organized into columns along [001] via C—H⋯O hydrogen bonds