In the title Schiff base, C(15)H(14)FN, the N=C bond length of 1.263 (2) Å is shorter than the N-C bond [1.426 (2) Å], indicating a typical imine double bond. Moreover, the C-N-C angle is 118.5 (2)°. The benzene rings form a dihedral angle of 51.22 (5)°.

A new tetra-dentate unsymmetrical Schiff base, C(15)H(10)N(4)O, has been synthesized from 4,5-dicyano-o-phenyl-enediamine and o-vanillin in refluxing ethanol. The dihedral angle between the two benzene rings is 39.0 (1)°. There are intra-molecular O-H⋯N and weak inter-molecular N-H⋯O and N-H⋯N inter-actions.

An intriguing 15-nickel metallamacrocyclic complex, [Ni15(EVan)10(H2O)20], (EVan = Schiff base formed between l-glutamic acid and o-vanillin), has been synthesized and characterized by single-crystal X-ray diffraction and spectroscopic analyses. adopts a Ni-O-Ni-O-Ni-O configuration and can be divided into five discrete trinuclear units.

The title Schiff base compound, C(15)H(14)N(2)O(3), was derived from the condensation reaction of salicylaldehyde with 4-methoxy-benzohydrazide. The dihedral angle between the two benzene rings is 2.5 (2)°. In the crystal structure, mol-ecules are linked through inter-molecular N-H⋯O hydrogen bonds, forming chains running along the b axis.

In the title Schiff base mol-ecule, C29H28N2O3, the three terminal benzene rings are twisted by 73.84 (15), 81.25 (16) and 12.1 (2)° with respect to the central benzene ring. An intra-molecular O-H⋯N hydrogen bond occurs. In the crystal, mol-ecules are linked via weak C-H⋯π inter-actions into a three-dimensional supra-molecular architecture.

In the mol-ecule of the title Schiff base compound, C(19)H(15)ClN(2)O(2), the dihedral angle between the benzene ring and naphthyl ring system is 77.1 (2)°. In the crystal structure, centrosymmetrically related mol-ecules are linked into dimers through pairs of inter-molecular N-H⋯O hydrogen bonds, generating rings of graph set R(2) (2)(8).

The title Schiff base, C18H15NO, crystallizes in its zwitterionic form and an N-H⋯O hydrogen bond closes an S(6) ring. The dihedral angle between the aromatic ring systems is 36.91 (10)°. Weak aromatic π-π stacking occurs in the crystal [minimum centroid-centroid separation = 3.7771 (15) Å].

Copper(II) forms 1:1 and 1:2 intense red complexes with phenanthraquinone monophenylthiosemicarbazone (PPT) at pH 3-3.5 and > or =6.5, respectively. These complexes exhibit maximal absorbance at 545 and 517 nm, the molar absorptivity being 2.3 x 10(4) and 4.8 x 10(4) l mol(-1) cm(-1), respectively. However, the 1:1 complex was quantitatively floated with oleic acid (HOL) surfactant in the pH ra...