Dimitra Kovala-Demertzi

Platinum(II) complexes with 2-acetyl pyridine thiosemicarbazone: Synthesis, crystal structure, spectral properties, antimicrobial and antitumour activity

An interesting series of new platinum complexes has been synthesized by the reaction of Na(2)PtCl(4) with 2-acetyl pyridine thiosemicarbazone, HAcTsc. The new complexes, [Pt(AcTsc)Cl], [Pt(HAcTsc)(2)]Cl(2) and [Pt(AcTsc)(2)], have been characterized by elemental analyses and spectroscopic studies. The crystal structure of the complex [Pt(AcTsc)Cl] has been solved by single-crystal X-ray diffraction. The anion of HAcTsc coordinates in a planar conformation to the central platinum(II) through the pyridyl N, azomethine N and thiolato S atoms. Double intermolecular hydrogen bonds (NH-Cl), pi-pi and weak Pt-Pt and Pt-pi contacts lead to aggregation and to a two-dimensional supramolecular assembly. The antibacterial and antifungal effect of the novel platinum(II) complexes and the related palladium(II) complexes, [Pd(AcTsc)Cl], [Pd(HAcTsc)(2)]Cl(2) and [Pd(AcTsc)(2)], were studied in vitro. The complexes were found to have a completely lethal effect on Gram+ bacteria, while the same complexes showed no bactericidal effect on Gram- bacteria. Additionally, the complexes [Pt(AcTsc)(2)] and [Pd(AcTsc)(2)] showed effective antifungal activity towards yeast. Among these compounds [33], the most effective in inducing antitumour and cytogenetic effects are the complexes [Pt(AcTsc)(2)] and [Pd(AcTsc)(2)] while the rest, display marginal cytogenetic and antitumour effects.

Platinum(II) and palladium(II) complexes with 2-acetylpyridine thiosemicarbazone: cytogenetic and antineoplastic effects.

The effect of three novel complexes of Pt(II) and three complexes of Pd(II) with 2-acetylpyridine thiosemicarbazone (HAcTsc) on sister chromatid exchange (SCE) rates and human lymphocyte proliferation kinetics on a molar basis was studied. Also, the effect of Pt(II) and Pd(II) complexes against leukemia P388 was investigated. Among these compounds, the most effective in inducing antitumor and cytogenetic effects were the complexes [Pt(AcTsc)2].H2O and [Pd(AcTsc)2] while the rest, i.e. (HAcTsc), [Pt(AcTsc)Cl], [Pt(HAcTsc)2]Cl2.2H2O, [Pd(AcTsc)Cl] and [Pd(HAcTsc)2]Cl2, displayed marginal cytogenetic and antitumor effects.

PALLADIUM(II) COMPLEXES OF 2-ACETYLPYRIDINE N(4) -METHYL, N(4)-ETHYL AND N(4)-PHENYL-THIOSEMICARBAZONES. CRYSTAL STRUCTURE OF CHLORO(2-ACETYLPYRIDINE N(4)-METHYLTHIOSEMICARBAZONATO) PALLADIUM(II). SYNTHESIS, SPECTRAL STUDIES, IN VITRO AND IN VIVO ANTITUMOUR ACTIVITY

The reactions of 2-acetylpyridine N(4)-methyl, (HAc4Me) N(4)-ethyl (HAc4Et) and N(4)-Phenyl (HAc4Ph) thiosemicarbazone with palladium(II) were studied. The ligands and the palladium(II) complexes have been characterized by spectroscopic techniques. The structure of [Pd(Ac4Me)Cl] has been determined by single-crystal x-ray diffraction. The protonation constants of HAc4Me and HAc4Et, Ka1 and Ka2, were determined by spectrophotometry. The effect of palladium compounds on DNA synthesis of P388 and L1210 cell cultures is also reported. Some of these compounds increased the life span of mice bearing tumors.

Palladium(II) and platinum(II) complexes of pyridine-2-carbaldehyde thiosemicarbazone with potential biological activity. Synthesis, structure and spectral properties. Extended network via hydrogen bond linkages of [Pd(PyTsc)Cl]

Abstract The reactions of Li2PdCl4 and Na2PtCl4 with pyridine-2-carbaldehyde thiosemicarbazone, HPyTsc, afforded the complexes [Pd(PyTsc)Cl], [Pd(PyTsc)2] and [Pt(PyTsc)Cl], [Pt(PyTsc)2]. The new complexes have been characterized by elemental analyses and spectroscopic studies. A crystal structure of [Pd(PyTsc)Cl] shows that the anion of PyTsc coordinates in a planar conformation to the central palladium(II) through the pyridyl N, azomethine N and thiolato S atoms. The planar molecules are linked into polymeric chains by N–H··N and N–H··S hydrogen bonding. The protonation constants of the ligand, Ka1 and Ka2, were determined by spectrophotometry and the logarithms of their values were found to be equal to 11.58±0.05 and 3.94±0.02 respectively. Correlation of the antitumor activity of these complexes to the structure and to reduction potential is reported. The compounds [Pt(PyTsc)2] and [Pd(PyTsc)2] were found to exhibit the higher in vivo antitumor activity and the lower cytotoxicity.

Coordinating properties of 2-acetylpyridine thiosemicarbazone. Palladium(II) complexes with neutral and deprotonated ligand. X-ray structure of bromo(2-acetylpyridine thiosemicarbazonato) palladium(II)

Abstract The preparation of the complexes PdLX, [Pd(HL) 2 ]X 2 and PdL 2 (X = Cl, Br; HL and L the neutral and deprotonated ligand) is described. The new complexes have been characterized by elemental analyses, conductivity measurements and spectroscopic (IR and UV-vis) studies and the crystal and molecular structure of PdLBr has been determined by single-crystal X-ray diffraction. The palladium atom has a square planar geometry with three donor atoms (NNS) coming from L to form a planar tricyclic ligating system, and one bromide atom. All data are discussed in terms of assigned structural type and the nature of the bonding. The protonation constants of the ligand, K a1 and K a2 , were determined by spectrophotometry and the logarithms of their values were found to be equal to 11.43 ± 0.02 and 3.98 ± 0.02.

Transition metal complexes of diclofenac with potentially interesting anti-inflammatory activity

An overview is given of the results of metal ion-diclofenac interactions. Several complexes have been synthesized at the University of Ioannina. Binuclear complexes, [Cu(L)2(H2O)]2 x 2H2O and [CuL2(S)]2 where S is H2O, EtOH, DMSO, (CH3)2CO and DMF, and mononuclear complexes, [MnL2(H2O)], [FeL2(H2O)2], [CoL2(H2O)2] x 0.5H2O, [CoL2(H2O)], [NiL2(H2O)2] x 2H2O, [NiL2] and [PdL2] x 2H2O, have been characterized by spectroscopy, X-ray crystallography and electrochemical studies. The catalytic activity of these complexes was correlated to the reduction potential. Some of the complexes of diclofenac exhibit very promising anti-inflammatory activity and act as antioxidant compounds, a property that is absent from diclofenac.

Synthesis and characterization of tetrakis-μ-2-[(2,6dichlorophenyl) amino] benzeneacetodiaquodicopper(II) dihydrate and tetrakis-μ-2-[(2,6dichlorophenyl)amino]benzeneaceto dimethylformamidodicopper(II)

Abstract Complexes of diclofenac (L), [CuL2(H2O)]22H2O, and [CuL2(DMF)]2 were prepared by the reaction of the sodium salt of this potent antiinflammatory drug with CuCl2. The new symmetric binuclear copper(II) complex [CuL2(DMF)]2 crystallizes in the monoclinic space group P21/n with cell constants a = 10.807(1), b = 15.429(2), c = 19.360(2), β = 92.508(3), V = 3225(1) A 3 , and Z = 2 . The structure was determined from 5456 out of a total of 5768 unique reflections. The final values for R1, wR2, and GOF for all data are 0.0602, 0.1066, and 1.030, respectively. The crystal structure consists of a binuclear quadruply bridged neutral molecule. The four carboxylato groups from four ligands are in the familar bidentate syn,syn η1:η1:μ2 bridging mode. The metal coordination geometry is described as a perfect square bipyramid with a water or dimethyloformamide oxygen occupying both apical positions. Optical, infrared, electron paramagnetic resonance, magnetic, and electrochemical properties of these complexes are also reported.

Synthesis, crystal structure, spectral properties and cytotoxic activity of platinum(II) complexes of 2-acetyl pyridine and pyridine-2-carbaldehyde N(4)-ethyl-thiosemicarbazones

The reactions of Na2PtCl4 with pyridine-2-carbaldehyde and 2-acetyl pyridine N(4)-ethyl-thiosemicarbazones, HFo4Et and HAc4Et respectively, afforded the complexes [Pt(Fo4Et)Cl], [Pt(HFo4Et)2]Cl2, [Pt(Fo4Et)2] and [Pt(Ac4Et)Cl], [Pt(HAc4Et)2]Cl2 x 2H2O, [Pt(Ac4Et)2]. The new complexes have been characterized by elemental analyses and spectroscopic studies. The crystal structure of the complex [Pt(Ac4Et)Cl] has been solved. The anion of Ac4E coordinates in a planar conformation to the central platinum(II) through the pyridyl N, azomethine N and thiolato S atoms. Intermolecular hydrogen, non-hydrogen bonds, pi-pi and weak Pt-pi contacts lead to aggregation and a supramolecular assembly. The cytotoxic activity for the platinum(II) complexes in comparison to that of cisplatin and thiosemicarbazones was evaluated in a pair of cisplatin-sensitive and -resistant ovarian cancer cell lines A2780 and A2780/Cp8. The platinum(II) complexes showed a cytotoxic potency in a very low micromolar range and were found able to overcome the cisplatin resistance of A2780/Cp8 cells.

Adducts of organotin(IV), tin(IV) and tin(II) halides with 1-methyl-imidazoline-2(3H)-thione (Hmimt) and imidazoline-2(1,3H)-thione (Himt). Synthesis, spectroscopic (IR, Mössbauer and 1H, 13C, 119Sn NMR) studies and in vitro antitumour activity

Abstract The reactions of 1-methyl-imidazoline-2(3 H )-thione (Hmimt) and imidazoline-2(1,3 H )-thione (Himt) with organotin(IV), tin(IV) and tin(II) halides were studied. Ten novel adducts were prepared and characterised by elemental analysis, conductivity measurements, IR, far-IR, 1 H NMR, 13 C NMR, 119 Sn NMR and Mossbauer spectroscopy. The ligands behave as monodentate and exhibit sulfur coordination. The structure of the complexes, in the solid state, is discussed in terms of the Mossbauer quadrupole splitting and the tin-ligand stretching vibrations in the IR and far-IR spectra. The behaviour of the adducts upon dissolution to D 2 O and CDCl 3 is also discussed. Octahedral dimeric and monomeric stereochemistries are assigned for organotin(IV) and tin(IV) adducts in the solid state. The in vitro antitumour activity against six human cell lines, MCF-7, EVSA (two breast cancers), WiDr (a colon cancer), IGROV (an ovarian cancer), M19MEL (a melanoma) and A498 (a renal cancer) for the adducts [SnBuCl 3 (Hmimt)] 2 , [SnMeCl 3 (Himt)] 2 and SnMe 2 Cl 2 (Himt) 2 is reported.

Palladium(II) complexes of 2-acetylpyridine N(4)-propyl, N(4)-dipropyl- and 3-hexamethyleneiminylthiosemicarbazones with potentially interesting biological activity. Synthesis, spectral properties, antifungal and in vitro antitumor activity

Abstract Some new palladium(II) complexes of 2-acetylpyridine N(4)-propyl- and N(4)dipropyl- and 3-hexamethyleneiminylthiosemicarbazones with potentially interesting biological activity were described. The thiosemicarbazones and their palladium(II) complexes have been characterized by spectroscopic, and electrochemical techniques. The protonation constants of HAc4P Ka1 and Ka2, were determined by spectrophotometry and the pK1a and pKa2 values are equal to 12.23 ±0.02 and 4.11 ±0.02. The antifungal properties and the effect selected compounds on DNA synthesis of P388 and L1210 cell cultures is reported.