Interactions of phenanthridinium–nucleobase conjugates with polynucleotides in aqueous media. Recognition of poly UElectronic supplementary information (ESI) available: materials and methods and CD titrations. See http://www.rsc.org/suppdata/cc/b2/b202615e/

Adenine containing conjugates 4 and 5 exhibit specific spectroscopic changes and two orders of magnitude higher affinity toward poly U than uracil conjugates 2 and 3 and the reference compound 1 due to the existence of specific interactions between adenine and uracil, possibly Watson-Crick hydrogen bonding between the bases stacked on the phenanthridinium moiety.