%0 Journal Article
%A Westerlund, Fredrik
%A Eng, Mattias P.
%A Winters, Mikael U.
%A Lincoln, Per
%D 2007
%T Binding Geometry and Photophysical Properties of DNA-Threading Binuclear Ruthenium
Complexes
%U https://acs.figshare.com/articles/journal_contribution/Binding_Geometry_and_Photophysical_Properties_of_DNA_Threading_Binuclear_Ruthenium_Complexes/3033514
%R 10.1021/jp065871v.s001
%2 https://ndownloader.figshare.com/files/4736152
%K intercalated conformation
%K solution
%K photophysical properties
%K complexes 2
%K Binding Geometry
%K protic solvents
%K bidppz
%K Photophysical Properties
%K dichroism spectra
%K DNA
%K radiative rate
%K emission quantum
%K hydrogen bonds
%K absorption bands
%X The DNA binding conformation and the photophysical properties of the semiflexible binuclear ruthenium
complex [μ-bidppz(phen)4Ru2]4+ (2) were studied with optical spectroscopy and compared to the rigid, planar
homologue in syn conformation [μ-dtpf(phen)4Ru2]4+ (3) and the parent “light-switch” complex [Ru(phen)2dppz]2+ (1). Comparison of calculated and observed absorption bands of the bridging ligand, bidppz,
confirm earlier suggestions that 2 is significantly nonplanar, both free in solution and when intercalated into
poly(dAdT)2, but the conclusion that the intercalated conformation is an anti rotamer is not substantiated by
comparison of linear and circular dichroism spectra of 2 and 3. The behavior of the emission quantum yield
as a function of temperature is similar for the two binuclear complexes 2 and 3 in different protic solvents,
and a quantitative analysis suggests that, in solution, the solvent is more strongly hydrogen bonded to the
excited state of 2 than to 1. However, the observation that for 2 the radiative rate constant increases to a
value similar to 1 upon intercalation into DNA suggests that the difference between 1 and 2 in accepting
hydrogen bonds is less pronounced when intercalated.
%I ACS Publications