Enantioselective binding of Λ- and Δ-[Ru(bpy)2(HPIP)]Cl2 (HPIP=2-(2-hydroxyphenyl)imidazo[4,5-f][1,10]phenanthroline) to the hexanucleotide [d(5′-GTCGAC-3′)2]

Multidimensional NMR techniques (1D (HNMR)-H-1, 2D DQF (HH)-H-1-H-1 COSY and 2D (HH)-H-1-H-1 NOESY), electrospray ionization mass spectrometry (ESI-MS) and electronic spectroscopy, were performed to study the interactions of the enantiomers Lambda- and Delta-[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 Delta-[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. Lambda-enantiomer binds weakly, suggesting groove interactions with the hexanucleotide duplex. ESI-MS spectrometry and UV-vis spectroscopy also confirmed these observations. (C) 2002 Elsevier Science Inc. All rights reserved.