Shape- and enantioselective interaction of Ru(II)/Co(III) polypyridyl complexes with DNA

Synthesis, DNA-binding and DNA-mediated luminescence quenching of Ru(II) polypyridine complexes

Two new polypyridyl ligands containing substituent Br at different positions in the phenyl ring, OBIP {OBIP = 2-(2-bromophenyl)imidazo[4,5-f]-1,10-phenanthroline}, PBIP {PBIP = 2-(4-bromophenyl)imidazo[4,5-f]-1,10-phenanthroline} and their Ru(II) complexes, [Ru(dmp)2(OBIP)]2+1 and [Ru(dmp)2(PBIP)]2+2
(dmp = 2,9-dimethyl-1,10-phenanthroline), have been synthesized and characterized. The binding of the two complexes to calf thymus DNA (CT DNA) has been investigated by spectrophotometric methods, viscosity measurements, as well as equilibrium dialysis and circular dichroism spectroscopy. Theoretical calculations for the two complexes were also carried out applying the density functional theory (DFT) method. The structure of complex 1 has been determined by single-crystal X-ray diffraction techniques. The imidazo[4,5-f]-1,10-phenanthroline moiety is not coplanar with the 2-bromophenyl ring, having a dihedral angle of 48.6° in the OBIP ligand. The twisted conformation has been further confirmed by theoretical calculations, in which this dihedral angle is 48.2°. The theoretical calculations also suggest that the PBIP ligand in complex 2 is essentially planar (dihedral angle is 0.4°). The experimental results show that while complex 1 binds to CT DNA via a semi-intercalative mode, complex 2 strongly binds to CT DNA through intercalation. Complex 2 is thus a much better candidate as an enantioselective binder to CT DNA than complex 1. Some experimental regularities or trends have been reasonably explained by the theoretical results. These suggest that the planarity of the intercalated ligand has significant effects on the spectral properties and the DNA-binding behavior of the complexes, and that the DFT method can be used effectively to explain and predict some regularities or trends in the interaction of polypyridyl Ru(II) complexes with DNA.

Effects of ligand planarity on the interaction of polypyridyl Ru(II) complexes with DNA

Polypyridyl ruthenium(II) complexes containing intramolecular hydrogen-bond ligand: syntheses, characterization, and DNA-binding properties

Twelve structurally diverse complexes, [Pb2(pzp)2(adip)(NO3)2] 1, [Pb(pzp)(glu)] 2, [Pb(pzp)(chdc)]·[Pb(pzp)(chdc)]·pzp·H2O 3, [Pb2(ndc)2(pzp)2(H2O)]·0.5H2O 4, [Pb(pzp)(1,3-bdc)(H2O)0.5]·H2O 5, [Pb(pzp)(1,2-bdc)]·H2O 6, [Pb2(ptc)2(adip)(NO3)2] 7, [Pb(ptc)(glu)] 8, [Pb(ptc)(chdc)] 9, [Pb(ptc)(dpdc)]2 10, [Pb(ptc)(1,3-bdc)]·2.5H2O 11, and [Pb(ptc)(1,4-bdc)]·0.75H2O 12, where H2adip = adipic acid, H2glu = glutaric acid, H2chdc = 1,4-cyclohexanedicarboxylic acid, H2ndc = 1,4-naphthalenedicarboxylic acid, 1,4-H2bdc = benzene-1,4-dicarboxylic acid, H2dpdc = 2,2′-diphenyldicarboxylic acid, 1,3-H2bdc = benzene-1,3-dicarboxylic acid, 1,2-H2bdc = benzene-1,2-dicarboxylic acid, pzp = pyrazino[2,3-f][1,10]phenanthroline, and ptc = 2-phenyl-1H-1,3,7,8,-tetraaza-cyclopenta[l]-phenanthrene, have been hydrothermally synthesized. Compounds 7 and 10 possess dinuclear structures, which are further extended by π−π interactions to form supramolecular layers and chains, respectively. 1−6, 8−9, and 11−12 feature chain structure...

A Series of Lead(II) Complexes with π−π Stackings: Structural Diversities by Varying the Ligands

Synthesis, characterization and luminiscent DNA-binding study of a series of ruthenium complexes containing 2-arylimidazo[f]1,10-phenanthroline

Syntheses, spectra and crystal structures of ruthenium(II) complexes with polypyridyl: [Ru(bipy)2(phen)](ClO4)2 · H2O and [Ru(bipy)2(Me-phen)](ClO4)2☆

Syntheses, crystal structures and spectroscopic characterization of [Co(phen)2(gly)]Cl2.4H2O and [Co(phen)2(H2O)2](NO3)3.2H2O

A series of new complexes [RuL2(pdphen)]2+, where pdphen is the planar ligand pyridino[3,2-f] [1,7]phenanthroline and L = 2,2′-bipyridine, phenanthroline, 2,9-dimethylphenanthroline or 5-nitrophenanthroline, were prepared and characterized. The binding of [RuL2-(pdphen)] 2+ to calf thymus DNA was investigated using absorption, fluorescence and circular dichroism (c.d.) spectroscopies. All of the complexes show absorption hypochromicity associated with binding to calf thymus DNA. [Ru(bipy)2pdphen]2+ and [Ru(phen)2pdphen]2+ also show fluorescence intensities and excited state life-time increases. The c.d. spectra of dialyzates from solutions of racemic complexes versus calf thymus DNA indicate enantioselectivity associated with binding to DNA.

Tian-Xian Zeng

Papers

Synthesis, characterization and luminiscent DNA-binding study of a series of ruthenium complexes containing 2-arylimidazo[f]1,10-phenanthroline

Syntheses, spectra and crystal structures of ruthenium(II) complexes with polypyridyl: [Ru(bipy)2(phen)](ClO4)2 · H2O and [Ru(bipy)2(Me-phen)](ClO4)2☆

Syntheses, crystal structures and spectroscopic characterization of [Co(phen)2(gly)]Cl2.4H2O and [Co(phen)2(H2O)2](NO3)3.2H2O

Synthesis, characterization and interaction with DNA of ruthenium(II) mixed-ligand complexes containing pyridino[3,2-f] [1,7]phenanthroline

Synthesis, characterization and cytotoxic studies of diimine palladium(II) complexes with amino acids and their dithiocarbamate derivatives