Synthetic, Crystallographic, and Computational Study of Copper(II) Complexes of Ethylenediaminetetracarboxylate Ligands

Copper(II) complexes of hexadentate ethylenediaminetetracarboxylic acid type ligands H4eda3p and H4eddadp (H4eda3p = ethylenediamine-N-acetic-N,N′,N′-tri-3-propionic acid; H4eddadp = ethylenediamine-N,N′-diacetic-N,N′-di-3-propionic acid) have been prepared. An octahedral trans(O6) geometry (two propionate ligands coordinated in axial positions) has been established crystallographically for the Ba[Cu(eda3p)]·8H2O compound, while Ba[Cu(eddadp)]·8H2O is proposed to adopt a trans(O5) geometry (two axial acetates) on the basis of density functional theory calculations and comparisons of IR and UV−vis spectral data. Experimental and computed structural data correlating similar copper(II) chelate complexes have been used to better understand the isomerism and departure from regular octahedral geometry within the series. The in-plane O−Cu−N chelate angles show the smallest deviation from the ideal octahedral value of 90°, and hence the lowest strain, for the eddadp complex with two equatorial β-propionate rings. A linear dependence between tetragonality and the number of five-membered rings has been established. A natural bonding orbital analysis of the series of complexes is also presented.

Synthesis, characterization, HSA/DNA interactions and antitumor activity of new [Ru(η6-p-cymene)Cl2(L)] complexes

Three new ruthenium(II) complexes were synthesized from different substituted isothiazole ligands 5-(methylamino)-3-pyrrolidine-1-ylisothiazole-4-carbonitrile (1), 5-(methylamino)-3- (4-methylpiperazine-1-yl)isothiazole-4-carbonitrile (2) and 5-(methylamino)-3-morpholine-4- ylisothiazole-4-carbonitrile (3): [Ru(η6-p-cymene)Cl2(L1)]·H2O (4), [Ru(η6 -pcymene)Cl2(L2)] (5) and [Ru(η6-p-cymene)Cl2(L3)] (6). All complexes were characterized by IR, UV-Vis, NMR spectroscopy, and elemental analysis. The molecular structures of all ligands and complexes 4 and 6 were determined by an X-ray. The results of the interactions of CT-DNA (calf thymus deoxyribonucleic acid) and HSA (human serum albumin) with ruthenium (II) complexes reveal that complex 4 binds well to CT-DNA and HSA. Kinetic and thermodynamic parameters for the reaction between complex and HSA confirmed the associative mode of interaction. The results of Quantum mechanics (QM) modelling and docking experiments toward DNA dodecamer and HSA support the strongest binding of the complex 4 to DNA major groove, as well as its binding to IIa domain of HSA with the lowest ΔG energy, which agrees with the solution studies. The modified GOLD docking results are indicative for Ru(p-cymene)LCl··(HSA··GLU292) binding and GOLD/MOPAC(QM) docking/modelling of DNA/Ligand (Ru(II)-N(7)dG7) covalent binding. The cytotoxic activity of compounds was evaluated by MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl2H-tetrazolium bromide) assay. Neither of the tested compounds shows activity against a healthy MRC-5 cell line while the MCF-7 cell line is the most sensitive to all. Compounds 3, 4 and 5 were about two times more active than cisplatin, while the antiproliferative activity of 6 was almost the same as with cisplatin. Flow cytometry analysis showed the apoptotic death of the cells with a cell cycle arrest in the subG1 phase

Hydrothermal Synthesis of CeO2 and Ce0.9Fe0.1O2 Nanocrystals

Pure and 10 mol% Fe3+ doped CeO2 nanocrystals were synthesized by hydrothermal method using two different basic solutions (NH4OH and NaOH). All the samples were calcinated at 140 degrees C and 200 degrees C. The characterization of crystalline structure, vibrational and optical properties was performed using X-ray diffraction, Raman spectroscopy and spectroscopic ellipsometry. The obtained results showed that the Fe-doped samples are solid solutions with different size of nanocrystals, very dependent on the synthesis temperature and type of basic solution. The Raman measurements demonstrated electron molecular vibrational coupling and increase of oxygen vacancy concentration whereas doping provokes a small decrease of optical absorption edge in comparison with pure ceria.International School and Conference on Photonics (PHOTONICA09), Aug 24-28, 2009, Belgrade, Serbi

Antiproliferative and Proapoptotic Activities of Methanolic Extracts from Ligustrum vulgare L. as an Individual Treatment and in Combination with Palladium Complex

The aim of this study is to examine the growth inhibitory effects of methanolic leaf and fruit extracts of L. vulgare on HCT-116 cells over different time periods and their synergistic effect with a Pd(apox) complex. The antiproliferative activity of plant extracts alone or in combination with the Pd(apox) complex was determined using MTT cell viability assay, where the IC50 value was used as a parameter of cytotoxicity. Results show that antiproliferative effects of L. vulgare extracts increase with extension of exposure time, with decreasing IC50 values, except for 72 h where the IC50 values for methanolic leaf extract were lower than for the fruit extract. The Pd(apox) complex alone had a weak antiproliferative effect, but combination with L. vulgare extracts caused stronger effects with lower IC50 values than with L. vulgare extracts alone. The type of cell death was explored by fluorescence microscopy using the acridin orange/ethidium bromide method. Treatments with plant extracts caused typical apoptotic morphological changes in HCT-116 cells and co-treatments with Pd(apox) complex caused higher levels of apoptotic cells than treatment with plant extracts alone. The results indicate that L. vulgare is a considerable source of natural bioactive substances with antiproliferative activity on HCT-116 cells and which have a substantial synergistic effect with the Pd(apox) complex

Nickel(II) complexes of whole set of the simple ethylenediaminetetracarboxylate ligands: DFT study of complexes invoking molecular orbital and configurational analysis

The whole set of the nickel(II) complexes with no derivatized edta-type hexadentate ligands has been investigated from their structural and electronic properties. Two more complexes have been prepared in order to complete the whole set: trans(O5)-Mg[Ni(ed3ap)]·8H2O and trans(O5O6)-Ba[Ni(eda3p)]·4H2O complexes. trans(O5) geometry has been verified crystallographicaly and trans(O5O6) geometry of the second complex has been predicted by the DFT theory and spectral analysis. Mutual dependance has been established between: the number of the five-membered carboxylate rings, octahedral/tetrahedral deviation of metal-ligand/nitrogen-neighbour-atom angles, charge-transfer energies (CTE) calculated by the Morokuma’s energetic decomposition analysis and energy of the absorption bands and HOMO–LUMO gap.

Configurational, LFDFT and NBO analysis of chromium(III) complexes of edta-type ligands

A new hexadentate chromium(III) complex, Na[Cr(1,3-pd3ap)]center dot 3H(2)O, containing an unsymmetrical edta-type ligand, the 1,3-propanediamine-N,N,N'-triacetate-N'-3-propionate ion (1,3-pd3ap), has been prepared, chromatographically separated and characterized. Only one [trans(O-5)] of the two possible geometrical isomers was isolated. In this isomer the two five-membered glycinate rings (R rings) occupy trans-axial sites, while the one glycinate ring and one beta-alaninate ring lie in the equatorial plane with the two diamine nitrogens (G rings). This result confirms the assignment made on the basis of Density Functional Theory (OFT), IR and UV-Vis spectral data analyses. The spectral data and electronic transition assignment, DFT-NBO, Ligand Field DFT and extensive strain analysis are discussed by a comparison with those of other [Cr(edta-type)](-) complexes of known configurations. The stoichiometry and stability of the complexes formed between the chromium(III) ion and 1,3-propanediamine-N,N,N'-triacetic-N'-propionic acid (H(4)1,3-pd3ap) were determined in aqueous solution by potentiometry at 25 degrees C and 0.1 M NaCl ionic strength. The existence of Cr(HnL), n = 0,1, 2 and 3 type complexes were verified. The formation of the Cr(OH)L complex was observed at higher pH values. The concentration distribution diagrams of the complexes were evaluated

Copper(II) complexes with unsymmetrical pentadentate ed3a-type diamino-tricarboxylate ligands. Crystal structures, configurational analysis and DFT study of complexes

The O-O-N-N-O-type pentadentate ligands H(3)ed3a, H(3)pd3a and H(3)pd3p (H(3)ed3a stands ethylenediamine-N,N,N'-triacetic acid; H3pd3a stands 1,3-propanediamine-N,N,N'-triacetic acid and H3pd3p stands 1,3-propanediamine-N,N,N'-tri-3-propionic acid) and the corresponding novel octahedral or square-planar/trigonal-bipyramidal copper(II) complexes have been prepared and characterized. H(3)ed3a, H(3)pd3a and H(3)pd3p ligands coordinate to copper(II) ion via five donor atoms (three deprotonated carboxylate atoms and two amine nitrogens) affording octahedral in case of ed3a(3-) and intermediate square-pyramidal/trigonal-bipyramidal structure in case of pd3a(3-) and pd3p(3-). A six coordinate, octahedral geometry has been established crystallographically for the [Mg(H2O)(6)][Cu(ed3a) (H2O)](2) center dot 2H(2)O complex and five coordinate square-pyramidal for the [Mg(H2O)(5)Cu(pd3a)][Cu(pd3a)] center dot 2H(2)O. Structural data correlating similar chelate Cu(II) complexes have been used for the better understanding the pathway: octahedral -> square-pyramidal trigonal- bipyramid geometry. An extensive configuration analysis is discussed in relation to information obtained for similar complexes. The infra-red and electronic absorption spectra of the complexes are discussed in comparison with related complexes of known geometries. Molecular mechanics and density functional theory (DFT) programs have been used to model the most stable geometric isomer yielding, at the same time, significant structural data. The results from density functional studies have been compared with X-ray data. (c) 2006 Elsevier B.V. All rights reserved

Structural, biological and computational study of oxamide derivative

A dicarboxylato-diamide-type compound 2,2'-[(1,2-dioxoethane-1,2-diyl)diimino]dibenzoic acid (H4obbz) (1) was synthesized and characterized. The crystal structure of K2H2obbz·2H2O (2) was determined by X-ray diffracttion analysis. The cytotoxic activities of the compounds were tested against four different cancer cell lines MCF-7, A549, HT-29, HeLa and a human normal cell line MRC-5. The results indicate reasonable dose-dependent cytotoxicity of the ligands that show selectivity against the tested carcinoma and healthy cell lines. Flow cytometric analysis and fluorescence microscopy showed that the most active compound, H4obbz, induced apoptosis and G0/G1 cell cycle arrest, indicating blockage of DNA synthesis as a possible mechanism that triggers apoptosis. Docking and molecular dynamics simulations gave similar responses regarding interactions (binding) between their ligands and chaperon Grp78. The MMGBSA determined ΔG binding energies were in the range from -104 to -140 kJ mol-1,

CCDC 900433: Experimental Crystal Structure Determination

Related Article: S.Belosevic, M.Cendic, A.Meetsma, Z.D.Matovic|2013|Polyhedron|50|473|doi:10.1016/j.poly.2012.11.029,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Square-pyramidal copper (II) complexes of linear tetradentate edda-type ligands forming six-membered rings. Molecular structures of [Cu(1,3-pdda) (H2O)] and [Cu(eddp) (H2O)] · 3.5H2O

Three square-pyramidal copper(II) complexes containing a linear O-N-N-O-type tetradentate ligand have been prepared and characterized. The ligands used are 1,3-propanediamine-N,N′-diacetate ion (1,3-pdda), ethylenediamine-N,N′-di-3-propionate ion (eddp) and 1,3-propanediamine-N,N′-di-3-propionate ion (1,3-pddp). In the three compounds a water molecule is in the axial position while the four atoms of ligand are in the basal plane. A five-coordinate, square-pyramidal geometry has been established crystallographically for the complexes [Cu(1,3-pdda)(H2O)] (1) (orthorhombic, Pnma, a = 8.937(4), b = 11.770(5), c = 10.269(5) Å3, V = 1080.2(8) Å3, Z = 4 and R = 0.0699) and [Cu(eddp)(H2O)] · 3.5H2O(2) (monoclinic, C2/c, a = 24.430(8), b = 12.195(3), c = 10.514(2) Å, β = 110.92(2) V = 2926(1) Å3, Z = 8 and R = 0.0515). The Cu(II) ions of these structures are lifted out of plane of the four in-plane ligand atoms by distances ρ = 0.182(5) and 0.154(1) Å, respectively. The six-membered diamine ring of complex 1 assumes the stable chair conformation. The other rings of chelates have expected conformations. The structural data correlating the square-pyramidal stereochemistry are discussed in relation to those obtained for similar complexes. The IR and electronic absorption spectra of [Cu(edda-type) (H2O)] complexes are discussed in comparison with those of related complexes of known geometries. The magnetic measurements are also reported for the complexes studied. © 1998 Elsevier Science S.A