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Publication Abstract from PubMed

The new complexes [Ru(TAP)2 (11-CN-dppz)](2+) , [Ru(TAP)2 (11-Br-dppz)](2+) and [Ru(TAP)2 (11,12-diCN-dppz)](2+) are reported. The addition of nitrile substituents to the dppz ligand of the DNA photo-oxidising complex [Ru(TAP)2 (dppz)](2+) promote pi-stacking interactions and ordered binding to DNA, as shown by X-ray crystallography. The structure of Lambda-[Ru(TAP)2 (11-CN-dppz)](2+) with the DNA duplex d(TCGGCGCCGA)2 shows, for the first time with this class of complex, a closed intercalation cavity with an AT base pair at the terminus. The structure obtained is compared to that formed with the 11-Br and 11,12-dinitrile derivatives, highlighting the stabilization of syn guanine by this enantiomer when the terminal base pair is GC. In contrast the AT base pair has the normal Watson-Crick orientation, highlighting the difference in charge distribution between the two purine bases and the complementarity of the dppz-purine interaction. The asymmetry of the cavity highlights the importance of the purine-dppz-purine stacking interaction.

X-ray Crystal Structures Show DNA Stacking Advantage of Terminal Nitrile Substitution in Ru-dppz Complexes.,McQuaid K, Hall JP, Brazier JA, Cardin DJ, Cardin CJ Chemistry. 2018 Oct 22;24(59):15859-15867. doi: 10.1002/chem.201803021. Epub 2018, Oct 1. PMID:30063271^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.