Palladium(II) complexes of dithiocarbamic acids: synthesis, characterization, crystal structure and DNA binding study (original) (raw)
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Inorganica Chimica Acta, 2021
Complexes [Pd(bipy)(mtzt) 2 ] (1) and [Pd(5,6-dmphen)(mtzt) 2 ] (2) (where Hmtzt, bipy and 5,6-dmphen are 1methyl-1H-1,2,3,4-tetrazole-5-thiol, 2,2′-bipyridine and 5,6-dimethyl-1,10-phenanthroline, respectively) were synthesized by the reaction of a mixture of Hmtzt and 2,2′-bipyridine (1) or 5,6-dimethyl-1,10-phenanthroline (2) with Pd(II) chloride. Complexes 1 and 2 were fully characterized by elemental analysis, 1 H NMR, IR, UV-Vis, luminescence spectroscopy as well as single-crystal X-ray diffraction method. According to single-crystal X-ray diffraction, central Pd(II) ions in 1 and 2 have a slightly distorted square-planar geometry, involving the S atoms from two mptrz − ligands and two nitrogen atoms from bipy (complex 1) and 5,6-dmphen (complex 2) ligands (τ 4 = 0.09 for 1 and 0.07 for 2). Additionally, some well-known non-covalent intermolecular interactions such as hydrogen bonding (complexes 1 and 2), π-π (complexes 1 and 2), and ring-metal interactions (complex 2) have also been involved in these complexes. These kinds of interactions have been observed to be responsible for the formation of the 3D supramolecular structure. The luminescence properties of the free ligand, as well as the complexes 1 and 2, were investigated in solution. The interaction of the complexes with DNA was investigated by UV-Vis absorption spectra. The results indicate that complexes bind to DNA and the intrinsic binding constant (K b) of complexes 1 and 2 were about 2.19 × 10 5 and 1.51 × 10 5 M −1 , respectively. Gel electrophoresis assay demonstrates the ability of the complexes to bind the plasmid DNA. The anti-tumor properties of Pd(II) complexes were evaluated as in vitro anti-proliferative activity by MTT assay in human breast cancer cell lines (MCF-7, SKBR-3, and MDA-MB-231). It suggests that complex 2 might dedicate important anti-tumor properties and 5,6-dmphen ligand has an important effect on cytotoxicity, so complex 2 shows IC 50 value in μM range as effective as cisplatin.
New dimeric and supramolecular mixed ligand Palladium(II) dithiocarbamates as potent DNA binders
Polyhedron, 2012
Five Pd(II)-based potential potent metallopharmaceuticals (1-5) of the general formula [(DT)Pd(PR 3)Cl], where DT = dibutyldithiocarbamate (1,2), dipropyldithiocarbamate (3), bis(2-methoxyethyl)-dithiocarbamate (4), dimethyldithiocarbamate (5); PR 3 = triphenylphosphine (1), diphenyl-p-tolylphosphine (2), diphenyl-t-butylphosphine (3), diphenyl-2-methoxyphenylphosphine (4), p-cholorodiphenylphosphine (5), have been synthesized and characterized using FT-IR, Raman, and multinuclear-NMR spectroscopy. The X-ray single crystal analysis (1 and 2) reveals the Pd(II) moiety is in a distorted square-planar arrangement with two positions being occupied by the bidentate dithiocarbamate ligand, while the other two positions are occupied by a phosphine ligand and a chloro group. The packing diagrams confirmed that the intermolecular ClÁ Á ÁH interactions are not only the main cause of deviation from an ideal square planar geometry, but are also responsible for the Pd-S bond lengths variation. The DNA binding ability of the complexes was examined by cyclic voltammetry (CV). The cyclic voltammograms of the synthesized metallopharmaceuticals followed irreversible electrochemical behavior, which indicate the high reactivity of the reduced form of complexes. The results obtained from CV evidenced the catalytic role of DNA in enhancing the electron transfer processes of the complexes. The DNA binding studies are expected to provide useful insights about the unexplored mechanism by which anticancer drugs exert their biochemical action.
Two new palladium complexes, [Pd(dpbs)Cl] (1) and [Pd 4 (dbbs) 4 ] (2) (where (dpbs) 2 = o,o'-(N,N'-dipicolinyldene)diazadiphenyl disulfide and (dbbs) 2 = N,N'-(1,1'-dithio-bis(phenylene))bis(salicylideneimine)), have been synthesized and characterized by analytical and spectral (electronic, IR, 1 H, 13 C spectroscopy) techniques. The structures of 1 and 2 have been solved by single-crystal X-ray diffraction experiments, which indicate distorted square planar coordination geometries around palladium(II) by O, N and S donors. The metal chelates have been screened for their antibacterial and antioxidant activities and compared with their respective ligands. The binding properties of the complexes have been studied by electronic absorption, emission spectroscopy and viscosity measurements. The competitive fluorescence study with ethidium bromide and the effect of iodide concentration on fluorescence of the complex-DNA system have been investigated. All these experimental results suggest that palladium complexes strongly bind to DNA, presumably via groove binding. The thermodynamic parameters, enthalpy change (ΔH°) and entropy change (ΔS°) were calculated by the Van't Hoff equation, suggesting hydrogen bonds play a predominant role in the binding of complexes to DNA.
Serbian Journal of Experimental and Clinical Research, 2021
The interactions of metal complexes with important biomolecules such as deoxyribonucleic acid (DNA) or bovine serum albumin (BSA) are responsible for their antitumor activity due to different modes of interaction with DNA and their transport through the blood system to cells and tissues via serum albumin. Therefore, the dinuclear palladium(II) complexes, [{Pd(en)Cl}2(μ-1,5- nphe)](NO3)2 (Pd1) and [{Pd(1,3-pd)Cl}2(μ-1,5-nphe)](NO3)2 (Pd2) (en is ethylenediamine, 1,3-pd is 1,3-propylenediamine and 1,5-nphe is the bridging 1,5-naphthyridine ligand) were synthesized and characterized by different spectroscopic methods. The UV-Vis and fluorescence emission spectroscopy were applied for evaluation of binding modes of Pd1 and Pd2 complexes to DNA as well as their interaction with BSA. The emission spectra indicate that the investigated Pd1 and Pd2 complexes can displace the ethidium bromide intercalator from DNA/EtBr molecules and act as intercalators showing strong interactions with DNA. ...
Polyhedron, 2018
The new palladium(II) complexes [Pd(L 1 /L 2)Cl] (1/2), with ONS donor azo-thioether ligands (HL 1 /HL 2), have been successfully synthesized. The complexes were thoroughly characterized by several spectroscopic techniques. The distorted square planar geometries of the complexes were confirmed by single crystal X-ray analysis. The electronic structures, redox and spectral properties are interpreted by DFT and TDDFT calculations. The interaction of the complexes with CT DNA was investigated by the UV-vis method and the binding constant was found to be 3.56 × 10 4 M-1 for 1 and 5.72 × 10 4 M-1 for 2. A competitive binding titration with ethidium bromide (EB) by the fluorescence titration method revealed that the complexes efficiently displace EB from the EB-DNA system and the Stern-Volmer dynamic quenching constant, K sv , was found to be 1.28 × 10 4 M-1 and 2.04 × 10 4 M-1 for 1 and 2 respectively.
Journal of Chemical Sciences
C-5-bromo-2-hydroxyphenylcalix[4]-2-methylresorcinarene (I) was synthesized by cyclocondensation of 5-bromo-2-hydroxybenzaldehyde and 2-methylresorcinol in the presence of concentrated HCl. Compound I was characterized by infrared and nuclear magnetic resonance spectroscopic data. X-ray analysis showed that this compound crystallized in a triclinic system with space group of Pī, a = 15.9592(16)Å, b = 16.9417(17)Å, c = 17.0974(17)Å, α = 68.656(3)°, β = 85.689(3)°, γ = 81.631(3)°, Z = 2 and V = 4258.6(7)Å 3. The molecule adopts a chair (C 2h) conformation. The thermal properties and antioxidant activity were also investigated. It was strongly antiviral against HSV-1 and weakly antibacterial against Gram-positive bacteria. Cytotoxicity testing on Vero cells showed that it is non-toxic, with a CC 50 of more than 0.4 mg/mL.
2013
The dinuclear complexes [Pd 2 (L) 2 (bipy) 2 ] (1), [Pd 2 (L) 2 (phen) 2 ] (2), [Pt 2 (L) 2 (bipy) 2 ] (3) and [Pt 2 (L) 2 (phen) 2 ] (4), where bipy = 2,2 0 -bipyridine, phen = 1,10-phenanthroline and L = 2,2 0 -azanediyldibenzoic dianion) dibridged by H 2 L ligands have been synthesized and characterized. The binding of the complexes with fish sperm DNA (FS-DNA) were investigated by fluorescence spectroscopy. The results indicate that the four complexes bound to DNA with different binding affinity, in the order complex 4 > complex 3 > complex 2 > complex 1, and the complex 3 binds to DNA in both coordination and intercalative mode. Gel electrophoresis assay demonstrates the ability of the complexes to cleave the pBR 322 plasmid DNA. The cytotoxic activity of the complexes was tested against four different cancer cell lines. The four complexes exhibited cytotoxic specificity and significant cancer cell inhibitory rate. Crown j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l oc a t e / j i n o r g b i o calcd. (%) for C 96 H 68 N 12 O 16 Pd 4 Á H 2 O (1): C, 64.38; H, 3.38; N, 6.93. Found (%): C, 64.45; H, 3.30; N, 6.85; IR (cm À1 , s, strong; m, medium; w, weak): m(O-H) 3421(m); m(@C-H) 3083(m); m(C@O) 1636(s); m(C@C) 1500(s), 1452(m); m(C-N) 1327(s); m(C@O) 1281(m); m(C-H) 750(m). 1 H NMR (DMF-d 7 , 300 MHz); tt, two triplet; t, triplet; d, doublet: d 7.48(tt, J = 7.5 Hz, 2H, Hf, Hf 0 ), 7.86(2t, 4H, Hb, Hb 0 , Hg, Hg 0 ), 7.96(d, J = 6.5 Hz, 2H, He, He 0 ), 8.40(tt, J = 13.8 Hz, 2H, Hc, Hc 0 ), 8.46(d, J = 6.9 Hz, 2H, Hh, Hh 0 ), 8.70(d, J = 7.5 Hz, 2H, Ha, Ha 0 ), 8.72(d, 2H, Hd, Hd 0 ).
Journal of Biological Inorganic Chemistry, 2022
The pincer complexes, [Pd(L 1)Cl]BF 4 (PdL 1), [Pd(L 2)Cl]BF 4 (PdL 2), [Pd(L 3)Cl]BF 4 (PdL 3), [Pd(L 4)Cl]BF 4 (PdL 4) were prepared by reacting the corresponding ligands, 2,6-bis[(1H-pyrazol-1-yl)methyl]pyridine (L 1), bis[2-(1H-pyrazol-1-yl)ethyl] amine (L 2), bis[2-(1H-pyrazol-1-yl)ethyl]ether (L 3), and bis[2-(1H-prazol-1-yl)ethyl]sulphide (L 4) with [PdCl 2 (NCMe)] 2 in the presence NaBF 4. The solid-state structures of complexes PdL 1-PdL 4 confirmed a tridentate coordination mode, with one chloro ligand completing the coordination sphere to afford square-planar complexes. Chemical behaviour of the complexes in solution confirms their stability in both aqueous and DMSO stock media. The electrochemical properties of the compounds showed irreversible two-electron reduction process. Kinetic reactivity of Pd complexes with the biological nucleophiles viz, thiourea (Tu), L-methionine (L-Met) and guanosine 5′-diphosphate disodium salt (5'-GMP) followed the order: PdL 2 < PdL 3 < PdL 4 , and PdL 2 < PdL 1. The kinetic reactivity is subject to the electronic effects of the spectator ligand(s), and the trend was supported by the DFT computed results. The palladium complexes PdL 1-PdL 4 bind to calf thymus (CT-DNA) via intercalation mode. In addition, the bovine serum albumin (BSA) showed good binding affinity to the complexes. The mode of quenching mechanism of the intrinsic fluorescence of CT-DNA and BSA by the complexes was found to be static. The order of interactions of the complexes with DNA and BSA was in tandem with the rate of substitution kinetics. The complexes, however, displayed relatively low cytotoxicity (IC 50 > 100 µM) when tested against the human cervical adenocarcinoma (HeLa) cell line and the transformed human lung fibroblast cell line (MRC-5 SV2).
Inorganica Chimica Acta, 2015
The interaction of three novel synthesized complexes of [Pd(phen)(R-gly)]NO 3 , where R-gly is methyl-, propyl-, and amyl-glycine; and phen is 1,10-phenanthroline were synthesized and characterized by spectroscopic methods. The interaction of ct-DNA with different concentrations of these palladium(II) complexes were studied by UV-Vis, fluorescence, circular dichroism spectroscopy, viscometric, and voltammetric measurements in Tris-HCl buffer solution containing 10 mM sodium chloride (pH 7.2) at 27 and 37°C as well as molecular dynamics (MD) simulation and molecular docking. The biological activity of the synthesized Pd(II) complexes was tested against chronic myelogenous leukemia cell line K562 at micromolar concentrations. Binding constants obtained by UV-Vis spectroscopy for methyl, propyl and amyl derivatives are as 5.08 Â 10 5 , 5.55 Â 10 5 , 7.08 Â 10 5 at 27°C and 5.53 Â 10 5 , 6.54 Â 10 5 , 10.01 Â 10 5 M À1 at 37°C, respectively. The experimental results suggested that these complexes cooperatively bind to DNA presumably via intercalation. Moreover, these Pd(II) complexes showed higher tendency to interact with DNA at higher concentrations and temperatures. These Pd complexes increase the T m , viscosity, and helicity of DNA solution. The binding data shows that methyl-derivative has higher tendency for binding to DNA. The trend of changes in the structural parameters such as calculated ASA, RMSD, hydrogen bond, and experimental viscosity were amyl > propyl > methyl. The results suggest that the synthesized Pd(II) complexes have dose-response suppression on growing of K562 leukemia cell line. Also, according to Cc 50 values, it is clear that the Pd(II) complex of methylglycine has higher cytotoxic or anti-proliferative effect against K562 leukemia cell line.