Effect of ancillary ligands on the DNA interaction of [Cr(diimine)3]3+ complexes containing the intercalating dipyridophenazine ligand.

(4)A(2g) (O(h)) emission wavelengths and lifetimes, and a variation of 110 mV in the (2)E(g) excited state oxidizing power. A detailed investigation has been undertaken of ancillary ligand effects on the DNA binding of these complexes with a range of polynucleotides. For all four complexes, emission is quenched by the addition of calf thymus B-DNA, with the emission lifetime data yielding bimolecular quenching rate constants close to the diffusion controlled limit. Equilibrium dialysis studies have established a general predilection for AT base binding sites, while companion experiments with added distamycin (a selective minor groove binder) provide evidence for a minor groove binding preference. For the case of [Cr(TMP)(2)(DPPZ)](3+), concomitant equilibrium dialysis and circular dichroism measurements have demonstrated very strong enantioselective binding by the Lambda optical isomer. The thermodynamics of DNA binding have also been explored via isothermal titration calorimetry (ITC). The ITC data establish that the primary binding mode for all four Cr(III) complexes is entropically driven, a result that is attributed to the highly favorable free energy contribution associated with the hydrophobic transfer of the Cr(III) complexes from solution into the DNA binding site. -->
Grant Information: P20 RR016461 United States RR NCRR NIH HHS; P20 RR-016461 United States RR NCRR NIH HHS
Substance Nomenclature: 0 (Ligands)
0 (Organometallic Compounds)
0 (Organoplatinum Compounds)
0 (Phenazines)
0R0008Q3JB (Chromium)
9007-49-2 (DNA)
91080-16-9 (calf thymus DNA)
Entry Date(s): Date Created: 20091231 Date Completed: 20100330 Latest Revision: 20211020
Update Code: 20221213
DOI: 10.1021/ic9013619
PMID: 20039692
Autor: Vandiver MS; Department of Chemistry, Furman University, Greenville, South Carolina 29613, USA., Bridges EP, Koon RL, Kinnaird AN, Glaeser JW, Campbell JF, Priedemann CJ, Rosenblatt WT, Herbert BJ, Wheeler SK, Wheeler JF, Kane-Maguire NA
Jazyk: angličtina
Zdroj: Inorganic chemistry [Inorg Chem] 2010 Feb 01; Vol. 49 (3), pp. 839-48.
DOI: 10.1021/ic9013619
Abstrakt: The synthesis of photoluminescent Cr(III) complexes of the type [Cr(diimine)(2)(DPPZ)](3+) are described, where DPPZ is the intercalating dipyridophenazine ligand, and diimine corresponds to the ancillary ligands bpy, phen, DMP, and TMP (where bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, DMP = 5,6-dimethyl-1,10-phenanthroline, and TMP = 3,4,7,8-tetramethyl-1,10-phenanthroline). For TMP, DMP, and phen as ancillary ligands, the complexes have also been resolved into their Lambda and Delta optical isomers. A comparison of the photophysical and electrochemical properties reveal similar (2)E(g) --> (4)A(2g) (O(h)) emission wavelengths and lifetimes, and a variation of 110 mV in the (2)E(g) excited state oxidizing power. A detailed investigation has been undertaken of ancillary ligand effects on the DNA binding of these complexes with a range of polynucleotides. For all four complexes, emission is quenched by the addition of calf thymus B-DNA, with the emission lifetime data yielding bimolecular quenching rate constants close to the diffusion controlled limit. Equilibrium dialysis studies have established a general predilection for AT base binding sites, while companion experiments with added distamycin (a selective minor groove binder) provide evidence for a minor groove binding preference. For the case of [Cr(TMP)(2)(DPPZ)](3+), concomitant equilibrium dialysis and circular dichroism measurements have demonstrated very strong enantioselective binding by the Lambda optical isomer. The thermodynamics of DNA binding have also been explored via isothermal titration calorimetry (ITC). The ITC data establish that the primary binding mode for all four Cr(III) complexes is entropically driven, a result that is attributed to the highly favorable free energy contribution associated with the hydrophobic transfer of the Cr(III) complexes from solution into the DNA binding site.
Databáze: MEDLINE
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