DNA Sequence and Ancillary Ligand Modulate the Biexponential Emission Decay of Intercalated [Ru(L)2dppz]2+ Enantiomers
Artikel i vetenskaplig tidskrift, 2012

The bi-exponential emission decay of [Ru(L)2dppz]2+ (L=N,N'-diimine ligand) bound to DNA has been studied as a function of polynucleotide sequence, enantiomer, and nature of L (phenanthroline vs. bipyridine). The lifetimes (ti) and pre-exponential factors (ai) depend on all three parameters. With [poly(dA-dT)]2, the variation of ai with [Nu]/[Ru] has little dependence on L for ?-[Ru(L)2dppz]2+ but a substantial dependence for ?-[Ru(L)2dppz]2+. With [poly(dG-dC)]2, by contrast, the ?-enantiomer ai values depend strongly on the nature of L, whereas those of the ?-enantiomer are relatively unaffected. DNA-bound linked dimers show similar photophysical behaviour. The lifetimes are identified with two geometries of minor-groove intercalated [Ru(L)2dppz]2+, resulting in differential water access to the phenazine nitrogen atoms. Interplay of cooperative and anti-cooperative binding resulting from complexcomplex and complexDNA interactions is responsible for the observed variations of ai with binding ratio. [Ru(phen)2dppz]2+ emission is quenched by guanosine in DMF, which may further rationalise the shorter lifetimes observed with guanine-rich DNA.

light-switch mechanism

binding

intercalation

DNA

minor-groove

photochemistry

luminescence lifetimes

ruthenium(ii)

metal-complexes

spectroscopy

dipyridophenazine complexes

electron-transfer

ruthenium

temperature

Författare

A. W. McKinley

Imperial College London

Johanna Andersson

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Per Lincoln

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Eimer Tuite

Newcastle University

Chemistry - A European Journal

0947-6539 (ISSN) 1521-3765 (eISSN)

Vol. 18 47 15142-15150

Ämneskategorier

Kemi

DOI

10.1002/chem.201201279