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Palladium(II) 4,5‐Diphenylimidazole Cyclometalated Complexes: DNA Interaction
Author(s) -
Zamora Félix,
González Víctor M.,
Pérez José M.,
Masaguer José R.,
Alonso Carlos,
NavarroRanninger Carmen
Publication year - 1997
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/(sici)1099-0739(199706)11:6<491::aid-aoc602>3.0.co;2-f
Subject(s) - chemistry , palladium , dimer , monomer , dna , stereochemistry , intercalation (chemistry) , agarose gel electrophoresis , ligand (biochemistry) , helix (gastropod) , molecule , circular dichroism , crystallography , base pair , organic chemistry , polymer , biochemistry , receptor , ecology , snail , catalysis , biology
In this paper, we show the synthesis of palladium(II) 4,5‐phenylimidazole cyclometalated complexes. They have been characterized by IR, 1 H‐ and 13 C‐NMR spectroscopy. The cyclometalated dimer compound 2 [Pd(C 15 H 11 N 2 )(μ‐OAc)] 2 and the cyclometalated monomer compound 5 [PdBr(SEt 2 )(C 15 H 11 N 2 )], having OAc and Br as leaving groups, interact with DNA, modifying its secondary structure (as measured by T m and CD), without modifying its tertiary structure (as determined by measurement of the electrophoretic mobility in agarose gels). The monomeric compound 5 seems to be the one that induces the highest alterations in DNA secondary structure since it strongly modifies the CD spectrum of the DNA. Melting data of drug–DNA complexes suggest that, at low drug concentration, the 4,5‐Imd ligand intercalates between the base pairs in the DNA molecule, increasing the T m , while at high drug concentrations the palladium(II) centers destabilize the double helix, producing a lowering in T m values. These results indicate that complexes containing planar structures might selectively bind to DNA that is not supercoiled, and that therefore it only has a secondary structure. © 1997 John Wiley & Sons, Ltd.