Photochromic azomethine disperse dyes with mercury(II) dithizonate moiety for dyeing hydrophobic fibres

84-88<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:calibri;mso-bidi-theme-font:minor-latin;="" color:black;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"="">Salicylidene-p-aminophenylmercuric acetate(II) was coupled with the diazotized<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:calibri;mso-bidi-theme-font:minor-latin;="" color:#242424;mso-ansi-language:en-us;mso-fareast-language:en-us;mso-bidi-language:="" ar-sa"="">/tetrazotized forms of arnines/diamines IIIa-u to give 5-arylazosalicylidene-p-aminophenylmercuric acetates (IVa-u) which on treatment with dithizone (V) gave 5-arylazosalicylidene-p-aminophenylmereury(II) dithizonates (VIa-u). When applied on nylon and polyester fibres, the compounds VIa-u showed poor to moderate fastness to light, very good to excellent fastness to rubbing and sublimation, and poor to excellent fastness to washing. The dyed fibres on exposure to bright sunlight showed very good photochromic effect. When the fibres were removed from sunlight the colour returned to the original shade, but the duration for this return depended on the intensity of incident light and ambient temperature.