Enantioselective binding of Λ- and Δ-[Ru(bpy) 2(HPIP)]Cl 2 (HPIP=2-(2-hydroxyphenyl)imidazo[4,5- f][1,10]phenanthroline) to the hexanucleotide [d(5′-GTCGAC-3′) 2

Abstract

Multidimensional NMR techniques (1D 1HNMR, 2D DQF 1H 1H COSY and 2D 1H 1H NOESY), electrospray ionization mass spectrometry (ESI-MS) and electronic spectroscopy, were performed to study the interactions of the enantiomers Λ- and Δ-[Ru(bpy) 2(HPIP)]Cl 2, (HPIP=2-(2-hydroxyphenyl)imidazo[4,5- f][1,10]phenanthro-line) with the self complementary hexanucleotide duplex d(5′-GTCGAC-3′) 2. The results show that the Δ-[Ru(bpy) 2(HPIP)]Cl 2 binds tightly to the oligonucleotide, by intercalation of the ligand HPIP, between the A5 and C6 base sequence of the same strand, probably through the minor groove. Λ-enantiomer binds weakly, suggesting groove interactions with the hexanucleotide duplex. ESI-MS spectrometry and UV-vis spectroscopy also confirmed these observations.