Ruthenium(II) terpyridyl complexes exhibiting DNA photocleavage: the role of the substituent on monodentate ligand.
J Phys Chem B
; 113(33): 11521-6, 2009 Aug 20.
Article
en En
| MEDLINE
| ID: mdl-19601613
ABSTRACT
Five ruthenium(II) complexes, [Ru(II)(tpy)(dppz)(py-R)](2+) (tpy = 2,2'6',2''-terpyridine; dppz = dipyrido[3,2-a2',3'-c]phenazine; py-R = 4-substituted pyridine; R = N(CH(3))(2), NH(2), OCH(3), H, NO(2)), were synthesized; and the substituent effects on the photophysical property, electrochemical property, DNA binding, and DNA photocleavage of the complexes were examined carefully. Increasing the electron-donating ability of the substituent R from NO(2) to N(CH(3))(2) leads to a cathodic shift of Ru-based oxidation potential, a red shift of the (1)MLCT absorption at room temperature and the (3)MLCT emission at 77 K, and enhancement of the DNA photocleavage ability. DNA photocleavage control experiments and the EPR spin-trapping technique confirm that the photocleavage abilities of the complexes originate from (1)O(2) production. Time-resolved absorption spectra suggest that the (3)MLCT lifetime plays an important role in the photosensitized (1)O(2) generation of these complexes, which in turn depends strongly on the electron-donating ability of the substituent R. By changing the substituent of pyridine from the electron-withdrawing to the electron-donating group, the photocleavage abilities of the complexes varied from inactive to active, providing a new strategy for the development of DNA photocleavers of tpy-based Ru(II) complexes.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
ADN
/
Compuestos de Rutenio
Idioma:
En
Revista:
J Phys Chem B
Asunto de la revista:
QUIMICA
Año:
2009
Tipo del documento:
Article