Helical Aggregation of Cyanine Dyes on DNA Templates: Effect of Dye Structure on Formation of Homo- and Heteroaggregates

• DOI: 10.1021/la025742f
• Publication Date: 2002-09-17T20:25:27Z
• Authors: Rachel A. Garoff; Elizabeth A. Litz...; Rebecca E. Connor; Irene Fishman; Bruce A. Armitage
• Keywords: Cyanine; Benzothiazole; Cationic polymerization; Benzoxazole

UV−visible and circular dichroism (CD) spectroscopic experiments were used to characterize DNA-templated helical aggregates formed from a variety of symmetrical, cationic cyanine dyes. Two types electronic couplings can be observed in these aggregates: face-to-face interactions between dye monomers end-to-end dimers. The yield approximately 4-fold stronger due greater orbital overlap. Variation the heterocyclic groups on reveals that aggregation DNA follows following trend: quinoline > benzothiazole benzoxazole dimethylindole. This trend tendency dyes aggregate aqueous solution. Within class dyes, dicarbocyanine (pentamethine bridge) much more readily than carbocyanine (trimethine analogue. However, tricarbocyanine (heptamethine less dicarbocyanine, contrast their relative water. In addition, heteroaggregates which two different associate cofacially template synthesized.