Preparation of J-Aggregated Microcrystals of Pseudoisocyanine

Abstract J-aggregated microcrystals of 1,1′-diethyl-2,2′-cyanine bromide [pseudoisocyanine bromide (PIC)] was prepared by salting-out in saturated potasium bromide aqueous solution, reprecipitation in hexane and recrystallization in polymers at room temperature. J-band of microcrystals from aqueous conditions was sharp and blue-shifted compared with those from hydrophobic conditions. The size of the former microcrystals was smaller than that of the latter ones.