Hajime Kanatomi

Photoisomerization and thermoisomerization I: Unusual photochromism of N-(3,5-di-tert-butyl-salicylidene) amines

Abstract Unusually photosensitive Schiff bases were prepared from 3,5-di-tert-butylsalicylaldehyde and amines; the aniline derivative exhibits both normal and reverse photochromism on irradiation with UV light followed by either storage in the dark or irradiation with visible light. From a consistent kinetics explanation of the thermal back reaction, two courses for the photo-bleaching and the thermal fading of the photochromer, which is assigned to a quinoid amine form, are illustrated.

Photoisomerization and thermoisomerization. III: tert-butyl method of selective preparation of photochromic crystalline salicylideneanilines and elucidation of substituent effects on the kinetics of the colour-change process

Abstract Salicylideneanilines possessing tert -butyl and other groups as ring substituents were synthesized and their photochemical properties were studied. The introduction of the bulky- tert -butyl substituent enabled photochromic Schiff base crystals to be prepared. Substituent effects on the photochromic phenomenon were determined by the kinetic measurement of the thermal bleaching reaction of the photocoloured species.

Resonance raman spectra of molecular oxygen adducts of Co(salen) and its derivatives in solution

Abstract Resonance Raman spectra of the molecular oxygen adducts of six Co(salen) derivatives have been measured in CH2Cl2 or CHCl3 containing pyridine using the mini-bulb method (∼−80°C, ∼4 atm O2 pressure). These adducts exhibit the O2 and CoO stretching bands at 1146−1143 and 530−515 cm−1, respectively. Although the former is insensitive to the nature of the in-plane ligand, the latter is sensitive to the geometry of the CoN2O2 core (steric effect) and the degree of π-conjugation over the entire chelate ring (electronic effect).

Photochromism of Guest N-Salicylideneaniline in the Rooms of Host Bile Acid Derivatives

Abstract Definite clathrate crystals of deoxycholic acid and its amide and alcohol derivatives as host molecules with N-salicylideneaniline as a guest molecule were prepared to investigate their photochromic properties. The photocoloration study was done by irradiating the crystal powder with 365 nm light; the thermal fading reaction of the photocolored species was followed by reflectance spectrophotometry at 303 K. From the sharp difference in the first-order rate constants of the thermal bleaching of the photochromes, it was found that the thermal unimolecular motion of photo-colored species was strongly influenced by the neighboring environments in the crystal state.

Trinuclear complexation of 2,6-bis(acetylacetoxymethyl)pyridine with Pd(II) and Cu(II) ions

Abstract Treatment of [PdCl 2 (PhCN) 2 ] with 2,6-disubstituted pyridines (L) gave a new series of trans -[PdCl 2 L 2 ] complexes. β-Ketoester substituents in the ligands were found to form OO chelate compounds with a Cu(II) ion. The Pd(II) complex of 2,6-bis(acetylacetoxymethyl)pyridine reacted with copper(II) acetate in dioxane to yield a (Cu(II), Pd(II), Cu(II)) trinuclear complex, which incorporated dioxane in the crystals. NMR, IR and reflectance spectra of the products were examined.

Deuterium isotope effect on the solid-state thermal isomerization of photo-coloured cis-keto species of N-salicylideneaniline

Deuterium isotope kinetic effect in the solid state was observed by using thermal fading reaction of photo-coloured species derived from N-salicylideneaniline deuterohydroxyl derivative; thus, the existence of a cis-keto form in the photo-coloured Schiff base crystals was suggested experimentally along with 6-methyl-substitution effect on the stability of the photoproduct.

Synthesis and structure of metal chelates of stilbenediamine schiff bases

Abstract Copper(II), Ni(II) and Co(II) chelates of Schiff bases derived from dl- and meso -stilbenediamine with acetylacetone, salicylaldehyde, and o -hydroxyacetophenone have been prepared. The structures of the metalchelates were inferred by means of electronic absorption spectra and found to be essentially square-planar. Exceptions are bis(acetylacetone)- meso -stilbenediiminatocopper(II) and bis( o -hydroxyacetophenone)- meso -stilbenediiminatocopper(II), which are fairly distorted from square-planar, probably because of the steric interactions between the equatorial phenyl group and the methyl group on the azomethine carbon atom. The conformation of the phenyl groups in the metal-chelates of the dl-isomers was investigated by the spectral behavior in pyridine and was concluded to be essentially diaxial relative to the metal-chelate plane. However, it is reasonable to conclude that conversion from the planar conformation takes place upon apical pyridine coordination in the case of bis(salicylaldehyde)-dl-stilbenediiminatocopper(II).

Utilization of crystal lattice cavities of host deoxycholic acid for achieving photochromism of guest salicylideneanilines in the crystal state

Salicylideneanilines have been easily incorporated in the crystal lattice cacities formed by deoxycholic acid molecules to yield clathrate compounds, which exhibit photochromism irrespective of the photosensitivity of the starting Schiff bases in the crystal state.