Diaqua-bis(pyrazine-2-carboxyl-ato-κN,O)manganese(II) dihydrate.

In the title compound, [Mn(C(5)H(3)N(2)O(2))(2)(H(2)O)(2)]·2H(2)O, the Mn(II) atom, lying on an inversion centre, has a distorted octa-hedral environment and the molecules are linked by O-H⋯O and N-H⋯O hydrogen bonds to form a three-dimensional supra-molecular structure.

(E)-4-Methyl-2-[(R)-1-phenyl-ethyl-imino-meth-yl]phenol.

In the title Schiff base, C(16)H(17)NO, the dihedral angle between the two aromatic rings is 63.59 (2)°. A strong intra-molecular O-H⋯N hydrogen bond is observed between the hydroxyl group and the imine N atom.

4,4'-Dimethyl-2,2'-[(3-aza-pentane-1,5-di-yl)bis-(nitrilo-methyl-idyne)]diphenol.

In the crystal structure of the title Schiff base, C(20)H(25)N(3)O(2), the salicylaldimine groups at each end of the mol-ecule are essentially planar and make a dihedral angle of 84.94 (3)° with each other. There are strong intra-molecular O-H⋯N hydrogen bonds and a weak inter-molecular N-H⋯O hydrogen bond.

Bis{2-[(E)-benzyl-imino-meth-yl]-4-methyl-phen-olato-κN,O}cobalt(II).

In the title complex, [Co(C(15)H(14)NO)(2)], the Co(II) atom, situated on an inversion centre, is coordinated by two O and two N atoms from two symmetry-related bidentate Schiff base ligands in a slightly distorted square-planar geometry. The two phenolate rings form a dihedral angle of 10.53 (2)°.

Synthesis, infrared and fluorescence spectra of lanthanide complexes with a new amide-based 1,3,4-oxadiazole derivative.

A new amide-based 1,3,4-oxadiazole derivative ligand 2,5-bis[2-(N,N-diethyl-1'-oxopropylamide)phenyl]-1,3,4-oxadiazole (L) and its complexes, Ln(NO3)3L (Ln=La, Eu, Gd, Tb, Er), were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The lanthanide ions were coordinated by O atoms from CO. The fluorescence properties of Eu(NO3)3L and Tb(NO3)3L in the solid state and in different solvents were investigated. Under the excitation of UV light, these complexes exhibit characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescent intensity were discussed.