Magnetic ordering versus lattice distortion in very narrow bands

A simple criterion for antiferromagnetic ordering versus lattice distortion in very narrow band materials is obtained. The model describing these narrow band materials contains the Hubbard Hamiltonian, short ranged interatomic Coulomb and exchange interactions, and the electron-phonon interaction.     

Preparation and characterization of mixed-ligand dihydrazone complexes of nickel(II)

Summary New complexes of Ni^II-containing dihydrazones derived from dehydroacetic acid as primary ligands and ammonia or pyridine as secondary ligand were prepared and characterized by elemental analysis, conductance, spectral and magnetic data. The dihydrazones react with NiCl₂ in their enolic forms as bis-tridentate complexing agents, forming dinuclear dihydrazido-diamine-dinickel complexes with ammino co-ligands. The ammino complexes were treated with pyridine to give the pyridino complexes. Squareplanar geometries are proposed for all the complexes and preliminary studies show that they possess antifungal activity.     

Synthesis of pyridin-2(1H)-one derivatives via enamine cyclization

The nucleophilic vinylic substitution reaction of the aliphatic enaminone 3-dimethylamino-2-formyl acrylonitrile 1 with the nucleophiles malononitrile and ethyl cyanoacetate produced the two unusual reaction adducts 3a and 3b in good to moderate yield under milder reaction conditions. Upon reaction with aromatic amines, these adducts yielded enamines 4 and 5, which eventually cyclized in the presence of base to produce the novel pyridin-2(1H)-one derivatives 8 and 9.