| abstract |
Proton carrier dyes (I), (II) and (III) for the NIR region are new. The dyes have a polymethine precursor (anhydro base) structure of formula (A), which changes reversibly to a polymethine structure of formula (B), i.e. styryl cyanine (IB), pyranomethine cyanine (IIB) and benzopyranomethine cyanine (IIIB), according to the pH. Q = a gp. of formula (IC), (IIC) or (IIIC): the other symbols are not defined. Pref. n = 0-4; R1,R2,R5-9 = H, alkyl, (hetero)aryl, heterocycloaliphatic, NO2, CN, halogen, alkoxy, OH, alkyl-substd. amine or cyclic amine; or R1+R2 = 1 or 2 aromatic rings; R3 = H, NO2, acetyloxy, halo, alkoxy or OH; R4 = H; R5' = H, Me, Et, 2-hydroxyethyl, haloethyl or 2-cyanoethyl; or R4+R5' = -(CH2)m-; m = 1-4; or N(R5')2 = satd. 5-24C (hetero)aliphatic ring; R'3, R'4 = H, alkyl or (het)aryl; or R'3 + R'4 and/or R'6 + R'7 = -(CH2)m- or -X-CH2-; X = O or S. provided that (a) R1, R2 are not halo when Q = (IC); and (b) R5-R8 are not carboxyphenyl when Q = (IC) or (IIC). |