Chart 1.

Chemical Structures of the 3,3′-Dialkylthiacarbocyanine Dyes Used in the Study^a

^a (A) n = 1 for DiSC₂(3), 3,3′-diethylthiadicarbocyanine, n = 2 for DiSC₃(3) 3,3′-dipropylthiadicarbocyanine, n = 3, for DiSC₄(3) 3,3′-dibutylthiadicarbocyanine, n = 4 for DiSC₅(3) 3,3′-dipentylthiadicarbocyanine; (B) tricationic thiacarbocyanine (3,3′-di(3-propylpyridinium)thiacarbocyanine) DiSC_py(3); and (C) structure of a photooxygenation product.