Dichlorido{N'-[phen-yl(pyridin-2-yl-κN)methyl-idene]isonicotinohydrazide-κ(2)N',O}zinc.

The title compound, [ZnCl(2)(C(18)H(14)N(4)O)], crystallizes with two mol-ecules in the asymmetric unit, which differ in the tautomeric (neutral and zwitterionic) forms of the coordin-ating organic ligand. In both mol-ecules, the Zn(II) atom adopts a distorted square-pyramidal geometry by two N and one O atoms of the Schiff base ligand and two Cl atoms acting as monodentate chloride anions. The crystal packing is stabilized by N-H⋯N and N-H⋯Cl hydrogen bonds, forming a two-dimensional network parallel to the ac plane.

Dichlorido[2-(pyridin-2-yl)-N-(pyridin-2-yl-methyl-idene)ethanamine-κ(3)N,N',N'']manganese(II) monohydrate.

In the title complex, [MnCl(2)(C(13)H(13)N(3))]·H(2)O, the Mn(II) atom is in a distorted square-pyramidal environment, with an Addison τ parameter of 0.037. The coordination geometry is defined by three N-atom donors from the tridentate 2-(pyridin-2-yl)-N-(pyridin-2-yl-methyl-idene)ethanamine ligand and two terminal Cl atoms. Although the H atoms of the lattice water molecule were not located, O⋯O distances of 3.103 (7) Šand O⋯Cl distances of 3.240 (3) and 3.482 (4) Šsuggest that hydrogen bonding is responsible for the stabilization of the crystal packing.

(S,E)-3-[(2-Hy-droxy-benzyl-idene)amino]-2-(2-hy-droxy-phen-yl)-2,3-dihydro-quinazolin-4(1H)-one.

In the title compound, C(21)H(17)N(3)O(3), the dihydro-quinazoline ring adopts a screw-boat conformation and its stereogenic C atom has an S configuration. The dihedral angle between the mean planes of the two hy-droxy-phenyl rings is 86.61 (12)°. The amino H atom forms an intra-molecular hydrogen bond with a phenol O atom, while the hydrazine N atom acts as an acceptor for the H atom of the other phenol group. In the crystal, O-H⋯N and O-H⋯O hydrogen bonds and weak C-H⋯centroid(π-ring) inter-molecular inter-actions are observed, forming chains along [1-10] and [110].

Bis{2-amino-2-oxo-N-[(1E)-1-(pyridin-2-yl-κN)ethyl-idene]acetohydrazidato-κ(2)N',O(1)}nickel(II).

In the title compound, [Ni(C(9)H(9)N(4)O(2))(2)], the Ni(II) ion is situated on a twofold rotation axis and is coordinated by two O and four N atoms from two tridentate {2-amino-2-oxo-N-[(1E)-1-(pyridin-2-yl-κN)ethyl-idene]acetohydrazidate ligands in a distorted octa-hedral geometry. In the crystal, N-H⋯O and N-H⋯N hydrogen bonds link the mol-ecules into columns in [001]. The porous crystal packing is further stabilized via π-π inter-actions between the pyridine rings of neighbouring mol-ecules [centroid-centroid distance = 3.746 (3) Å] with voids of 270 Å(3).

Bis(2-{[2-(2-hy-droxy-benzyl-amino)-eth-yl]amino-meth-yl}phenolato-κN,N',O)cobalt(III) nitrate monohydrate.

In the title compound, [Co(C(16)H(19)N(2)O(2))(2)]NO(3)·H(2)O, the Co(III) ion is located on an inversion center and is six-coordinated by two phenolate O atoms and four amino N atoms from two diamine ligands, forming an octa-hedral geometry. The water mol-ecule and the nitrate anion are located close to an inversion center, and are thus equally disordered by symmetry. The crystal packing is stabilized by inter-molecular O-H⋯O hydrogen bonds involving the uncoordinated water mol-ecule and the free phenol hydroxyl group with the nitrate anion. N-H⋯O hydrogen bonds involving the amino groups and the nitrate anions connect the complex mol-ecules along the c axis.

Bis(N,N'-dimethyl-ethylenediammonium) tris-(oxalato-κO,O)cobaltate(II) dihydrate: an ion-pair complex.

The Co(II) ion in the title complex, (C(4)H(14)N(2))(2)[Co(C(2)O(4))(3)]·2H(2)O, is coordinated by three oxalate ions, resulting in a distorted octa-hedral geometry. Two uncoordinated water mol-ecules are present in asymmetric unit. Inter-molecular N-H⋯O and O-H⋯O hydrogen bonds between the different entities stabilize the crystal structure.

{2-[(2-Acetyl-hydrazin-1-yl-idene)methyl-κN,O]-6-methoxy-phenolato-κO}(nitrato-κO)copper(II) monohydrate.

In the title complex, [Cu(C(10)H(11)N(2)O(3))(NO(3))]·H(2)O, prepared from the Schiff base N'-(3-meth-oxy-2-oxidobenzyl-idene)-acetohydrazide, the Cu(II) atom is coordinated by two O atoms and one N atom from the ligand and one O atom from a nitrate group in a distorted square-planar geometry. The Cu(II) atom has a weak inter-action with another O atom of the nitrate group. The two O atoms of the tridentate Schiff base ligand are in a trans arrangement. O-H⋯O and N-H⋯O hydrogen bonds involving the uncoordinated water mol-ecule are observed.