Cation supported self-assembly of coordination polymers, [(H 2en)(ntpMCl 2)] n (M = Zn II, Cd II, Hg II) involving the tripodal acid, ntp: X-ray crystal structure and DNA binding studies on zinc helicate (original) (raw)
Related papers
Transition Metal Chemistry, 2008
A new series of 14-membered pendant arm hexaazamacrocyclic complexes of the type [MLX2] · [M = Co(II), Ni(II), Cu(II) or Zn(II) for X = Cl; Co(II), Ni(II), Cu(II) or Zn(II) for X = NO3] has been synthesized by metal template condensation of 1,2-phenylenediamine and 1,4-phenylenediamine with formaldehyde in methanol. The mode of bonding and overall geometry of these complexes have been deduced by elemental analyses, molar conductance values, FT-IR, 1H-NMR, 13C-NMR, EPR, ESI-mass and UV–VIS along with magnetic measurement studies. The fluorescence and UV–VIS studies revealed a significant binding ability to DNA.
Journal of Molecular Structure, 2019
[Zn(OOCCH 2 C 6 H 4 OH) 2 ] n (1) and [(Phen)Zn(OOCCH 2 C 6 H 4 OH) 2 ] (2) were made by the reaction of zinc(II) acetate dihydrate with 4-hydroxyphenylacetic acid in the absence and presence of 1,10-phenenthroline, respectively. The complex 1 crystallizes as coordination polymer formed by the mÀh 1 ,h 1 carboxylate bridged tetrahedral zinc centers. The complex 2 comprises a distorted octahedral zinc center coordinated by the two bidentate carboxylates and a bidentate 1,10-phenanthroline. Thermal stabilities of the complexes were studied by TG and DTA techniques at varied heating rates (10 C/min, 15 C/min and 20 C/min). Both complexes follow a two-stage degradation processes with the formation of ZnO as the final residue where complex 2 has higher energetic stability compared with complex 1. The kinetic and thermodynamic parameters were calculated from the TG curves employing the Horowitz-Metzger method. Zinc complexes were examined for their DNA binding abilities by UVevis spectroscopic analysis and structurally rationalized by the docking studies. The binding constant values (K b) for DNAcomplex interactions were found to be 7.7 Â 10 4 M-1 and 2.94 Â 10 4 M-1 for complexes 1 and 2, respectively. Complex 1 interacted with DNA exclusively by hydrogen bond formation whereas complex 2 developed both hydrogen and arene-cation interactions with the active residues of DNA.
Effect of structure variations on the quadruplex DNA binding ability of nickel Schiff base complexes
Two different series of nickel Schiff base complexes were prepared as part of a study aimed at discovering new compounds with high affinity and selectivity for quadruplex DNA (qDNA). The new complexes were prepared by modification of a literature method for synthesising N,N'-bis-(4-((1-(2-ethyl)piperidine)-oxy)salicyli-dene)phenylenediaminenickel(II) (complex (1)). For Series 1 complexes, the phenylenediamine head group of the literature complex was replaced with ethylenediamine, phenanthrenediamine, R,R-and S,S-diamino-cyclohexane. These complexes, as well as an asymmetric molecule featuring a naphthalene moiety on one side and a single ethyl piperidinyl salicylidene group on the other, were prepared in order to examine the effect of varying the number and position of aromatic groups on DNA binding. Series 2 complexes were isomers of those in Series 1, in which pendant ethyl piperidine groups were located at different positions. All new complexes were characterised by 1D and 2D NMR spectroscopic methods alongside microanalysis and ESI-MS. In addition, the solid state structures of eight new complexes were determined using single crystal X-ray diffraction methods. N,N'-Bis-(4-((1-(2-ethyl)piperidine)oxy)-salicylidine)diaminophenanthrenenickel(II) (9), was shown by ESI-MS, CD spectroscopy and UV melting studies to exhibit a greater affinity towards, and ability to stabilise, dsDNA than all other complexes in the first series. ESI-MS revealed (9) to have a strong tendency to form a 1 : 1 complex with the tetramolecular, parallel qDNA molecule Q4, however it exhibited low affinity towards the parallel unimolecular qDNA molecule Q1. The enantiomeric complexes (5) and (7), featuring R,R-and S,S-diaminocyclohexane moieties, respectively, showed similar binding profiles towards all DNA molecules investigated, whereas the asymmetric complex (11), exhibited very low DNA affinity in all cases. Series 2 complexes showed very similar DNA affinity and selectivity to their isomeric counterparts in Series 1. For example, (14) and (15), both of which contain a phenylenediamine head group, showed higher affinity towards D2, Q1 and Q4, than any of the other Series 2 complexes. In addition, complex (21), which contains a meso-1,2-diphenylethylenediamine moiety, interacted strongly with Q4, but not D2 or Q1. This observation was very similar to that made previously for the isomeric complex (3).
Journal of the American Chemical Society, 1993
The self-association and DNA-binding properties of two benzopyridoindole derivatives, 3-methoxy-7H-8- pyrido[ 4,3-b] indole (BePI) and 3-methoxy-7-[ (( 3'-diethy1amino)propyl)amino]-10-methyl-1 1 H-benzo[g]pyrido[4,3-b]indole (BgPI), have been investigated by a variety of NMR, spectrophotometric, fluorescence, and hydrodynamic techniques. N M R studies indicate that both BePI and BgPI selfassociate in solution, probably forming multimers (n-mers) in the process. BgPI self-associates with a 3-fold (at 80 "C) to 12-fold (at 27 "C) higher affinity than BePI. Self-association interactions do not interfere with those between either ligand and DNA at total ligand concentrations 110-5 M. Thermodynamic (van't Hoff) analyses of the selfassociation interactions of both ligands indicate that they are enthalpically driven, consistent with those of other aromatic dyes. Furthermore, at temperatures ranging from 22 to 80 O C , BgPI self-associated complexes are 1.2-1.5 kcal/mol more stable than the corresponding BePI self-associated complexes. The solvent exchange properties of the exchangeable protons of both BePI and BgPI, as determined by N M R studies in H20 at [multimer]/[monomer] ratios of =4, reveal exchange in the following order as a function of either pH or temperature: IO-NH > 11-NH >> 7-NH >> 3'-NH for BePI and 8-NH > 7-NH >> 11-NH >> 3'-NH for BgPI (see for numbering systems of atoms).
Structure and DNA-binding properties of bis(quinolonato)bis(pyridine)zinc(II) complexes
Polyhedron, 2009
Dr. Aris Terzis has been a dominant chemical figure among the Greek scientist during the last 30 years. His significant contributions by X-ray crystallographic to structural characterization of bioinorganic models, metal-based drugs, inorganic and organic catalysts, inorganic materials and magnetic clusters was the key factor for the dramatic improvement of the quality of the papers published by Greek scientists. Therefore we feel that it is appropriate to dedicate this contribution to Dr. Aris Terzis on the occasion of his retirement.
Synthesis, crystal structure and DNA interaction studies on mononuclear zinc complexes
Inorganica Chimica Acta, 2011
A new family of mononuclear Zn(II) complexes [Zn(Pyimpy) 2 ](ClO 4) 2 (1), [Zn(Pyimpy)(Cl) 2 ] (2), [Zn(Pyimpy)(SCN) 2 ] (3) and [Zn(Pyimpy)(N 3) 2 ] (4) were synthesized using designed tridentate ligand Pyimpy having NNN donors (Pyimpy: (2-((2-phenyl-2-(pyridin-2-l)hydazono)methyl)pyridine)). Complexes were characterized by different spectroscopic studies and it has been found out that all complexes exhibited strong fluorescent emission at room temperature. Molecular structures of [Zn(Pyimpy) 2 ] (ClO 4) 2 ÁC 6 H 5 CH 3 Á0.5H 2 O (1ÁC 6 H 5 CH 3 Á0.5H 2 O) and [Zn(Pyimpy)(Cl) 2 ]ÁCH 3 CN (2ÁCH 3 CN) were determined by X-ray crystallography and ligand coordinated Zn(II) ions was described as distorted octahedral and distorted square pyramidal, respectively. DNA binding properties of these complexes were investigated by absorption spectral, fluorescence quenching and circular dichroism spectral studies.
Biochemistry, 2003
DNA minor groove ligands provide a paradigm for double-stranded DNA recognition, where common structural motifs provide a crescent shape that matches the helix turn. Since minor groove ligands are useful in medicine, new ligands with improved binding properties based on the structural information about DNA-ligand complexes could be useful in developing new drugs. Here, two new synthetic analogues of AT specific Hoechst 33258 5-(4-methylpiperazin-1-yl)-2-[2′-(3,4-dimethoxyphenyl)-5′-benzimidazolyl] benzimidazole (DMA) and 5-(4-methylpiperazin-1-yl)-2-[2′{2′′-(4-hydroxy-3-methoxyphenyl)-5′′-benz-imidazolyl}-5′-benzimidazolyl] benzimidazole (TBZ) were evaluated for their DNA binding properties. Both analogues are bisubstituted on the phenyl ring. DMA contains two ortho positioned methoxy groups, and TBZ contains a phenolic group at C-4 and a methoxy group at C-3. Fluorescence yield upon DNA binding increased 100-fold for TBZ and 16-fold for DMA. Like the parent compound, the new ligands showed low affinity to GC-rich (K ≈ 4 × 10 7 M-1) relative to AT-rich sequences (K ≈ 5 × 10 8 M-1), and fluorescence lifetime and anisotropy studies suggest two distinct DNA-ligand complexes. Binding studies indicate expanded sequence recognition for TBZ (8-10 AT base pairs) and tighter binding (∆T m of 23°C for d (GA 5 T 5 C). Finally, EMSA and equilibrium binding titration studies indicate that TBZ preferentially binds highly hydrated duplex domains with altered A-tract conformations d (GA 4 T 4 C) 2 (K) 3.55 × 10 9 M-1) and alters its structure over d (GT 4 A 4 C) 2 (K) 3.3 × 10 8 M-1) sequences. Altered DNA structure and higher fluorescence output for the bound fluorophore are consistent with adaptive binding and a constrained final complex. Therefore, the new ligands provide increased sequence and structure selective recognition and enhanced fluorescence upon minor groove binding, features that can be useful for further development as probes for chromatin structure stability. † U.T. is thankful to the Council of Scientific and Industrial Research, India for financial assistance as a fellowship.
Journal of Molecular Structure, 2018
The present study reports the synthesis and evaluation of nonlinear optical property and G-Quadruplex DNA Stabilization of five novel copper(II) mixed ligand complexes. They were synthesized from copper(II) salt, 2,5-and 2,3-pyridinedicarboxylic acid, diethylenetriamine and amide based ligand (AL). The crystal structure of these complexes were determined through X-ray diffraction and supported by ESI-MAS, NMR, UV-Vis and FT-IR spectroscopic methods. Their nonlinear optical property was studied using Gaussian09 computer program. For structural optimization and nonlinear optical property, density functional theory (DFT) based B3LYP method was used with LANL2DZ basis set for metal ion and 6-31G * for C,H,N,O and Cl atoms. The present work reveals that pre-polarized Complex-2 showed higher β value (29.59 x 10-30 e.s.u) as compared to that of neutral complex-1 (β = 0.276 x 10-30 e.s.u.) which may be due to greater advantage of polarizability. Complex-2 is expected to be a potential material for optoelectronic and photonic technologies. Docking studies using AutodockVina revealed that complex-2 has higher binding energy for both G-Quadruplex DNA (-8.7Kcal/mol) and duplex DNA (-10.1 Kcal/mol). It was also observed that structure plays an important role in binding efficiency.
Tetra-stranded metallo-supramolecular cylinders. design, synthesis and DNA binding studies
2013
Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder. Recently new ways have been reported for recognition of other DNA structures (vide infra). 1.2.1. Major groove recognition The DNA major groove is targeted by many proteins and large synthetic or semi-synthetic agents. However, since most synthetic drugs are relatively small for the major groove, little research has been focused in the recognition of the DNA major groove. (10) Recently, a tetra-substituted naphthalene diimide compound functionalized with positively charged N-methyl-piperazine side chains has been shown to bind and thermally stabilize the 3'-ends of human telomeric G-tetrads of quadruplexes. The four side chains interact with the grooves of the quadruplex while the naphthalene core interacts via - stacking to the DNA bases (Figure 1.27). It has also been found to be a potent inhibitor of cell growth. (75) Holliday junctions can be recognized by a number of proteins in cells which direct branch migration and resolution during the homologous recombination process. The binding is structurally selective, however proteins can also distort the junction structure upon binding. (92,93) Scheme 1.2: Synthesis of iron(II) triple helicate. Crystal structure shows M enantiomer. (CCDC 622770). (84) This helicate is able to coil and bend DNA by binding around the major groove. (120) It can also recognize the central cavity of DNA and RNA three-way
Salicylaldehyde 2-phenylquinoline-4-carboylhydrazone (H 2 L), and its novel copper(II), cobalt(II), and nickel(II) complexes MHL Á Cl Á nH 2 O [M=Cu n = 3 (1), M=Co n = 2 (2), M=Ni n = 3.5 (3)] have been synthesized and characterized by elemental analysis, molar conductivity, spectroscopic, and thermal analysis. The interaction of these complexes with calf thymus DNA was investigated by UV absorption spectroscopy, fluorescence spectroscopy, cyclic voltammetry, and viscosity measurements. The results suggest that these complexes bind to DNA via an intercalation binding mode and their affinity to DNA follows the order of 3 [ 1[ 2.