| Research Abstract |
Stimulus responsive molecules have been a subject of much recent interest because of their potentiality in wide range of material science. In this context, development of new responsive molecules of varieties with respect to the kinds of input-stimuli as well as properties responding to them. In this research project, several new responsive molecules have been synthesized, which showed responsivities such as piezo-pH,piezochromism, photo-pka, photochromism, as follows. 3,6-Dimitrothioxanthene-10,10-dioxide and 3-cyano-6-nitrothioxanthene-10,10-dioxide showed piezochromism upon pressing to give rise to color developing. The mechanism of the piezochromism has been studied in detail, that is, the conjugate base formed by the C (9) -H dissociation gave the color. This system changes the degree of the proton dissociation responding to pressure, and the phenomenon is closely relevant to piezo-pH change. This idea has been extended to light regulation of molecular acidity pka. It was intended
… More
to control the acidity of thioxanthene-10-10-dioxide by the light-driven structural change of a photoresponsive substituent introduced to the molecular skeleton. Thus, 3-methoxycarbonyl-6-trans-phenylazothioxanthene-10-10-dioxide and 3-methoxycarbonyl-6-trans-phenylazothioxanthene-10-10-dioxide were synthesized. The phenylazo group showed reversible trans/cis photo-isomerization, and the molecules of the trans form revealed much larger acidity than the cis-form. It has been intended to extend the light-driven property changes to the Redox potentials of a molecule. For this purpose, tri-butyl-polyacenequinones were synthesized. They undergo reversible photoisomerization between the corresponding valene isomer. The isomerizations are accompanied by large change in the pai-electronic structure, and as a result, are accompanied by large change in the Redox potential of the molecules. It was well known that the C60 possess an unique responsivity towards light. In order to materialize the property, it should be important to fix the molecule to solid materials. In this context, a new method for making C-C bond to C60 has been developed. Less
|
