Synthesis of Novel Iono- and Photochromic Spiropyrans Derived from 6,7-Dihydroxy-8-Formyl-4-Methyl-2H-Chromene-2-One

Table 2

Spectral characteristics of isomers A, B for (4a–f) and lifetimes for photoinduced absorption in toluene at 293 K.

Comp.	^A𝜆^absmax, (nm)	^B𝜆^absmax, (nm)	𝜏, s
4a	295, 354, 370	458, 614	161
4b	298, 355, 371	459, 617	205.7
4c	294, 354sh, 370	456, 619	170.9
4d	295, 354, 370	461, 617	44.1
4e	299, 356, 370	459, 614	257.7
4f	299, 355sh, 371	471, 653	6.5