Synthesis and Photoreactions of Aromatic Diols Containing Bis (Azo) and Bis (O-Nitrobenzyl) Chromophores

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Aromatic diols containing bis (azo) and bis (o-nitrobenzyl) chromophores viz., (4-hydroxyphenylazo)-2,2/-dinitrodiphenylmethane, 4-hydroxy-3-methylphenylazo-4/-hydroxyphenyl-azo-2,2/-dinitrodiphenyl methane and bis (4-hydroxy-3-methylphenylazo)-2-dinitrodiphenyl methane were synthesized from 4,4-diamino-2,2/-dinitrodiphenylmethane and phenol/0-cresol. As a result of photolysis, the azo group of the diols unergo trans-cis isomerisation and one of the o-nitrobenzyl groups of the diols undergo trans-cis isomerisation and one of the o-nitrobenzyl groups in them undergo redox reaction to nitronitrosocarbinol. There occurred a solubility difference between the irradiated and unirradiated diol. In solution, a photoswtiching behaviour was also observed.

Aromatic diols; bis(azo); bis(o-nitrobenyl); photoswtiching; nitronitrosocarbinol