Binding geometry and photophysical properties of DNA-threading binuclear ruthenium complexes
Journal article, 2007

The DNA binding conformation and the photophysical properties of the semiflexible binuclear ruthenium complex [mu-bidppz(phen)(4)Ru-2](4+) (2) were studied with optical spectroscopy and compared to the rigid, planar homologue in syn conformation [mu-dtpf(phen)(4)Ru-2](4+) (3) and the parent "light-switch" complex [Ru(phen)(2)dppz](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.

Author

Fredrik Westerlund

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Mattias P Eng

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Mikael Winters

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Per Lincoln

Chalmers, Chemical and Biological Engineering, Physical Chemistry

Journal of Physical Chemistry B

1520-6106 (ISSN) 1520-5207 (eISSN)

Vol. 111 1 310-317

Subject Categories

Physical Chemistry

DOI

10.1021/jp065871v

More information

Created

10/8/2017