{N'-[(E)-1-(5-Bromo-2-oxidophen-yl)ethyl-idene-κO]-4-methyl-benzohydrazidato-κN',O}(pyridine-κN)nickel(II).

The central Ni(II) atom in the title complex, [Ni(C(16)H(13)BrN(2)O(2))(C(5)H(5)N)], is in a square-planar trans-N(2)O(2) environment defined by the NO(2) donor atoms of the tridentate hydrazone ligand and the monodentate pyridine ligand. The pyridine mol-ecule forms a dihedral angle of 9.99 (11)° with the least-squares plane through the NiN(2)O(2) atoms.

trans-Bis(N'-isopropyl-idene-benzo-hydrazidato-κN',O)bis-(pyridine-κN)nickel(II).

The complex mol-ecule of the title compound, [Ni(C(10)H(11)N(2)O)(2)(C(5)H(5)N)(2)], has a crystallographically imposed centre of symmetry. The Ni(II) atom is coordinated in a distorted octa-hedral geometry by the O and N atoms of two trans arranged anionic bidentate hydrazone ligands forming the equatorial plane and by the N atoms of two pyridine mol-ecules at the axial positions. In the crystal, inter-molecular C-H⋯N hydrogen bonds link the mol-ecules into columns parallel to the b axis.

N'-[(E)-1-(5-Bromo-2-hy-droxy-phen-yl)ethyl-idene]-4-nitro-benzohydrazide.

The title compound, C(15)H(12)BrN(3)O(4), displays a trans conformation with respect to the C=N double bond. The central atoms around the C=N double bond are not coplanar, in contrast to the aromatic rings, which exhibit a dihedral angle of 1.80 (4)° between their mean planes. An intra-molecular O-H⋯N hydrogen bond occurs. In the crystal, mol-ecules are connected via inter-molecular N-H⋯O hydrogen bonding into chains along the a axis.

1-Benzoyl-3,5-diphenyl-4,5-dihydro-1H-pyrazole.

In the title compound, C(22)H(18)N(2)O, the pyrazole ring is almost planar (r.m.s. deviation = 0.0098 Å) and its mean plane makes dihedral angles of 62.2 (2), 87.2 (2) and 8.0 (2)° with the phenyl and benzoyl rings, respectively. The crystal packing is stabilized by π-π stacking inter-actions [centroid-centroid distance = 3.658 (2) Å] and weak inter-molecular C-H⋯O hydrogen bonds.

{N'-[(E)-(5-Bromo-2-oxidophen-yl)(phen-yl)methyl-ene]benzohydrazidato}pyridine-copper(II).

The asymmetric unit of title complex, [Cu(C(20)H(13)BrN(2)O(2))(C(5)H(5)N)], contains two independent mol-ecules. In each mol-ecule, the central Cu(II) atom has a square-planar environment formed by the tridentate hydrazone and the monodentate pyridine ligands, with the N atoms in a trans arrangement about the Cu(II) atom.

{N'-[(E)-(5-Bromo-2-oxidophen-yl)(phenyl)-methyl-ene]-4-chloro-benzo-hydrazidato}pyridine-nickel(II).

The asymmetric unit of title complex, [Ni(C(20)H(12)BrClN(2)O(2))(C(5)H(5)N)], contains one complex with the central Ni atom in a slightly distorted square-planar environment, formed by the tridentate hydrazone and the monodentate pyridine ligands, with N atoms in a trans arrangement about the Ni atom.

N'-[(E)-(5-Bromo-2-hydroxy-phen-yl)(phen-yl)methyl-ene]benzohydrazide.

In the title compound, C(20)H(15)BrN(2)O(2), the C=N double bond displays a trans configuration. The crystal structure features an intra-molecular O-H⋯N hydrogen bond.

{N'-[(E)-(5-Bromo-2-oxidophen-yl)(phen-yl)methyl-ene]benzohydrazidato}pyridine-nickel(II).

The asymmetric unit of title complex, [Ni(C(20)H(13)BrN(2)O(2))(C(5)H(5)N)], contains two independent mol-ecules. In each mol-ecule, the central Ni(II) atom has a square-planar environment, formed by the tridentate hydrazone and the monodentate pyridine ligands, with the N atoms in a trans arrangement about the Ni(II) atom.

N'-[(E)-(5-Bromo-2-hydroxy-phen-yl)(phen-yl)methyl-idene]-4-chloro-benzo-hydrazide.

The Schiff base, C(20)H(14)BrClN(2)O(2), displays a trans conformation with respect to the C=N double bond. The aromatic rings at either end of the -C(=O)-NH-N=C- fragment are nearly parallel [dihedral angle = 3.4 (5)°]. The hydr-oxy group forms an intra-molecular hydrogen bond to the imino N atom.

(5-Bromo-2-hydroxy-phen-yl)(phen-yl)methanone.

In the title compound, C(13)H(9)BrO(2), the dihedral angle between the aromatic ring planes is 53.6 (1)°. The crystal structure is stabilized by intra-molecular O-H⋯O and inter-molecular C-H⋯O hydrogen bonding and C-H⋯π inter-actions.

N'-[(E)-1-(5-Bromo-2-hydroxy-phen-yl)ethyl-idene]benzohydrazide.

The C=N double bond in the title compound, C(15)H(13)BrN(2)O(2), is transE configured and the dihedral angle between the aromatic ring planes is 22.3 (1)°. The crystal structure is stabilized by intra-molecular O-H⋯O and inter-molecular N-H⋯O hydrogen bonds.