Takeo Nagahara

Chloroacetylation or bromoacetylation on the methine carbon of an asymmetrical quadridentate schiff base copper(II) complex

Abstract Chloroacetylation or bromoacetylation on the methine carbon of the title complex was performed, in the absence of a catalyst with chloroacetyl chloride or bromoacetyl bromide respectively. The compounds obtained were confirmed by means of electronic and IR spectra, as well as elemental analyses. The fact that electrophilic substitutions occurred on the chelate ring of the complex might demonstrate a quasiaromaticity of the ring.

The preparation and some properties of copper(II) and nickel(II) schiff base complexes having various peripheral substituent groups

Abstract The hydrogen atom on methine carbon of N,N′-bis(acetylacetone)ethylenediaminatocopper(II) or -nickel(II) was found to be replaced by a chlorine, bromine or iodine atom. Further conversion of the halogen atom of the complex occurred with a sodium salt of phenol, benzenethiol or succinimide. The UV data of substituted compounds give some information on substituents.

Action of N-bromosuccinimide on methine carbons of N,N′-bis(benzoylacetone)ethylenediaminatonickel(II) and -copper(II)

Abstract By the action of N-bromosuccinimide on ,N′-bis(benzoylacetone)ethylene-diamine complexes of nickel(II) and copper(II), both the bromo and succinimido substitutions on methine carbons occured. Three products were simultaneously obtained: dibromo-, bromo-succinimido-, and disuccinimido substituted complexes.

THE NUCLEOPHILIC RING SUBSTITUTIONS OF ASYMMETRICAL TETRADENTATE SCHIFF BASE COMPLEXES OF NICKEL(II) AND COPPER(II)

Seven new complexes where the chelate ring was nucleophilically substituted were synthesized by the reactions of asymmetrical tetradentate Schiff base complexes of nickel(II) and copper(II) with benzenethiols and thiolycollic ehtyl ester. They were characterized by means of elemental analyses, electronic and 1H-NMR spectra. Kinetics of the nucleophilic ring-substitution reactions were spectrophotometrically studied in a benzene solution. A four-centered intermediate is proposed for the reactions.

Binuclear schiff base complexes of nickel(II) or copper(II) linked by dithiols as a bridging group

Abstract Binuclear Schiff base complexes of nickel(II) or copper(II) were synthesized by bridging unsymmetrical Schiff base complexes of nickel(II) and copper(II) with 2,5-dimercapto-1,3,4-thiadiazole or 2-mercaptoethyl ether. Although the magnetic susceptibility and ESR measurements showed that copper(II)copper(II) interaction of the binuclear copper(II) complexes is very weak in the solid state, they catalyzed chemiluminescence of luminol by hydrogen peroxide in DMF solution, suggesting that small amounts of the complexes might be present in the form of the appropriate copper(II)copper(II) distance to activate hydrogen peroxide in solution.

Preparation of trinuclear adducts from quadridentate schiff base copper(II) complexes with metal(II,III) nitrate

Abstract Trinuclear adducts of a quadridentate Schiff base copper(II) complex were prepared with metal(II,III) nitrate, where metal ions are Cu(II), Ni(II), Zn(II) Ca(II), Mg(II), Sr(II), Y(III), La(III) and Nd(III). They were characterized by means of elemental analyses, UV and IR spectra, as well as magnetic susceptibilities. Planarity of a copper environment in the Schiff base complex is enhanced in the order of a parent Schiff base complex, its binuclear adduct and the trinuclear. In a series of alkaline earth(II) and lanthanoid(III) adducts, two characteristic infrared bands arising from NO frequencies of a nitrate group were observed around 1750 cm −1 , which demonstrates that the nitrate groups coordinate to the central metal(II,III) ions. The kinds of counter anions of the metal(II,III) salts are one of the important factors which control the adduct formations.

Study of the reaction mechanism of asymmetrical quadridentate Schiff-base complexes of nickel(II) with N-bromosuccinimide

Abstract In the ring-substitution reaction of [N-(1-methyl- 3-oxo-3-phenylpropylidene)-N′-salicylideneethylene- diaminato]nickel(II) with N-bromosuccinimide, it was spectrophotometrically confirmed that the bromination occurred first, followed by the succinimido substitution, where N-bromosuccinimide acted as both an electrophile and a nucleophile.

THE NUCLEOPHILIC RING SUBSTITUTION OF (3-BROMO-2,4-PENTANEDIONATO)COPPER(II)

Abstract While the bromine atom of bis(3-bromo-2,4-pentanedionato)-copper(II) could not be substituted for nucleophiles such as succinimide, phthalimide, phenol, and benzenethiol, the salts of these nucleophiles produced bis(3-substituted 2,4-pentanedionato)-copper(II) complexes

Kinetics for the reaction of methine proton of an unsymmetrical tetradentate Schiff base complex of nickel(II) with N-chlorosuccinimide

The substitution reaction of the methine proton of an unsymmetrical tetradentate Schiff base complex of nickel(II) with N-chlorosuccinimide was kinetically studied in a dichloromethane solution. While the rate of chlorination was decreased by the addition of acetone or ether, the rate was significantly increased by the addition of ethanol. The rate of bromination was faster than that of chlorination. A four-centred intermediate was proposed for the halogenation reaction of the Schiff base nickel(II) complex.