Studies On The Synthesis, Structures And Photochemical Properties Of Schiff Base Containing Thiosemicarbazone Moiety

Photochromism is defined as a reversible transformation between two isomers having different absorption spectra by photoirradiation. In recent years, with the increasing demand for materials which can store optical information, various types of photochromic compounds systems have been extensively studied because not only color but also other properties such as refractive index, fluorescence, magnetic properties, electron transfer, and structural features which can be reversibly transformation between two tautomers by photoirradiation. One reason for that is the possibility that rewritable optical memories may use organic photochromic compounds as media for high capacity ultra fast computing storage devices. Although many photochromic compounds have been reported, compounds which show photochromic reactivity in crystalline phases are rare.Pyrazolone and their derivates are widely known as having a large range of biological properties such as antiviral, antibacterial, antimalarial, antifungal, etc, but little attention is paid to the photochromic thiosemicarbazones. In earlier studies, we have reported a series of novel photochromic 4-acyl pyrazolone thiosemicarbazone derivates and discussed their crystal structures, and these photochromism show high thermal stability in crystalline phase and have promising potential for optoelectronic devices. The photochromic mechanism of these 4-acyl pyrazolone thiosemicarbazone photochromic materials was analyzed and presumed by studying the properties and crystal strutures of the photochromic compounds. The relation between the structure and properties has been obtained.In the first part, five new 4-acyl pyrazolone thiosemicarbazones compounds: 1-phenyl-3-methyl-4-(-furoyl)-5-pyrazolone thiosemicarbazone (PMαFP-TSC),...