Catherine Dendrinou-Samara

Anti-inflammatory drugs interacting with Zn(II), Cd(II) and Pt(II) metal ions

Complexes of Zn(II), Cd(II) and Pt(II) metal ions with the anti-inflammatory drugs, 1-methyl-5-(p-toluoyl)-1H-pyrrole-2-acetic acid (Tolmetin), alpha-methyl-4-(2-methylpropyl)benzeneacetic acid (Ibuprofen), 6-methoxy-alpha-methylnaphthalene-2-acetic acid (Naproxen) and 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid (indomethacin) have been synthesized and characterized. In the structurally characterized Cd(naproxen)2 complex the anti-inflammatory drugs acts as bidentate chelate ligand coordinatively bound to metal ions through the deprotonated carboxylate group. Crystal data for 1: [C32H26O8Cd], orthorhombic, space group P22(1)2(1), a = 5.693(2) (A), b = 8.760(3) (A), c = 30.74(1) (A), V = 1533(1) A3, Z = 2. Antibacterial and growth inhibitory activity is higher than that of the parent ligands or the platinum(II) diamine compounds.

Copper(II) complexes with phenoxyalkanoic acids and nitrogen donor heterocyclic ligands: structure and bioactivity

The copper complexes with the phenoxyalkanoic acids MCPA, 2,4-D, 2,4,5-T and 2,4-DP in the presence of a nitrogen donor heterocyclic ligand, phen or bipyam, were prepared and characterized. Interaction of Cu(II) with phenoxyalkanoic acids and bipyam leads to dinuclear or uninuclear neutral complexes while in the presence of phen uninuclear neutral or cationic forms have been isolated. The crystal structure of bis(1,10-phenanthroline)(2-methyl-4-chloro-phenoxyacetato)copper(ll) chloride-methanol(1/1)-water(1/0.6), 1 has been determined and refined by least-squares methods using three-dimensional MoK, data. 1 crystallizes in space group P1, in a cell of dimensions a = 14.577(6)A, b = 1 1.665(5) A, c = 12.249(6) A, alpha = 98.38( 1)degrees, beta = 112.18( 1) degrees, gamma = 104.56(1 ) degrees, V= 1,798( 1) A3 and Z= 2. The cyclic voltammograms of uninuclear cationic complexes in dmf exhibit an extra cathodic wave due to the chloride ion. The available evidence supports an increasing antimicrobial effeciency for the cationic complexes.

High nuclearity nickel compounds with three, four or five metal atoms showing antibacterial activity.

The effect on DNA and the antibacterial activity of a series of high nuclearity nickel compounds with three, four and five metal atoms were examined. The compounds have a mixed ligand composition with salicylhydroxamic acid and di-2-pyridyl-ketonoxime as chelate agents. In the trinuclear compound Ni(3)(shi)(2)(Hpko)(2)(py)(2)(1), two metal ions show a square planar geometry while the third one is in an octahedral environment. The compounds with four and five nickel atoms construct metallacrown cores with two distinct connectivities. The tetranuclear vacant metallacrown [12-MC(Ni(II)N(Hshi)2(pko)2)-4](2+) shows the connectivity pattern [-O-Ni-O-N-Ni-N-](2), while the pentanuclear ([Ni(II)][12-MC(Ni(II)N(shi)2(pko)2)-4])(2+) follows the pattern [-Ni-O-N-](4). Two distinct arrangements of the chelates around the ring metal ions were observed; a 6-5-6-5-6-5-6-5 arrangement for the [12-MC(Ni(II)N(Hshi)2(pko)2)-4] core and a 6-6-5-5-6-6-5-5 arrangement for the [12-MC(Ni(II)N(shi)2(pko)2)-4] core. Magnetic variable temperature susceptibility study of the trinuclear compound revealed the presence of one paramagnetic nickel(II) ion with strong crystal field dependence, with D=5.0(4) cm(-1), g(xy)=2.7(3) and g(z)=2.3(3). The effect of the synthesized Ni(II) complexes on the integrity and electrophoretic mobility of nucleic acids was examined. Only compounds 2, 3 and 4 altered the mobility of pDNA, forming high molecular weight concatamers at low concentrations or precipitates at higher concentrations. Antibacterial activity screening of the above compounds suggests that nickel compounds 2, 3 and 4 were the most active and can act as potent antibacterial agents.

CuII-herbicide complexes: structure and bioactivity

Abstract Copper complexes with the commercial auxin herbicides 2,4-dichlorophenoxy-acetic acid (2,4-D), 3,4-dichlorophenoxy-acetic acid (3,4-D), 2,4,5-trichlorophenoxy-acetic acid (2,4,5-T), 2-methyl-4-chloro-phenoxy-acetic acid (MCPA), 2,3-dichlorophenoxy-acetic acid (2,3-D) and 2-(2,4-dichlorophenoxy)-propanoic acid (2,4-DP) in the presence or not of 2,2′-bipyridine (bipy), an antimicrobial agent, were prepared and characterized. The available evidence supports a dimeric structure for the 2,3-D complex, while the presence of bipy leads to monomeric forms. The solution behaviour of dinuclear complexes in dimethylformamide (DMF) has shown that the complexes are converted to monomeric compounds by the addition of more than 1:2 of bipy. The cyclic voltammograms of dimers in DMF suggest that the complexes retain the dimeric structure in solution. The electron spin resonance spectra of the compound (aqua)(2,2′-bipyridine)bis(2-methyl-4-chloro-phenoxyacetato) copper(II) (I) show features characteristic of the presence of an S = 1 triplet state. The crystal structure of 1 was determined and refined by least-squares methods using three-dimensional Mo Kα data. 1 crystallizes in the space group C2 c , in a cell of dimensions a=40.49(1), b=7.286(3), c=19.617(6) A , β=103.23(1)°, V=5634(3) A 3 , Z=8 . Study of the antimicrobial activity showed that the presence of bipy increases the efficiency 4–8 times.

Host–Guest Interaction of 12‐MC‐4, 15‐MC‐5, and Fused 12‐MC‐4 Metallacrowns with Mononuclear and Binuclear Carboxylato Complexes: Structure and Magnetic Behavior

Interaction of manganese with salicylhydroxamic ligands leads to the formation of the 12-membered metallacrown [Mn(II)(2(2,4-DP)2(HCOO)2]-[12-MC(Mn(III)N(shi)-4](py)6 (2) (H-2,4-DP =2-(2,4-dichlorophenoxy)propionic acid) and the 15-membered metallacrown [Mn(II)(2,4-D)2][15-MC(Mn(III)N(shi)-5](py)6 (1) (H-2,4-D = 2,4-dichlorophenoxyacetic acid). The crystal structure analysis shows that mononuclear and dinuclear alkanoato complexes are accommodated in the cavity of the metallacrown ring. The magnetic behaviour of 1 and 2 and the magnetic behaviour of the fused 12-membered metallacrown [Ni(II)(mcpa)]2-[12-MC(Ni(II)N(shi)2(pko)2-4][12-MC(Ni(II)N(shi)3(pko)-4]-(CH3OH)3(H2O) (3) (Hmcpa = 2-methyl-4-chlorophenoxyacetic acid) have shown that the zero field and/or the population of many energy levels at low temperatures is the reason for the divergence of the susceptibility data at high fields. For compound 3, the ground state is S = 0, with S = 1 and S = 2 low-lying excited states. This leads to a non-Brillouin behaviour of the magnetisation, since the ground state is very close to the excited states.

15-MC-5 manganese metallacrowns hosting herbicide complexes. Structure and bioactivity.

Interaction of manganese with salicylhydroxamic ligands leads to the formation of a series of 15-membered metallacrown Mn(II)(L)(2)[15-MC(Mn(III)N(shi))-5](py)(6) (L=alkanoato ligand). The crystal structure contains a neutral 15-membered metallacrown ring of the type [15-MC(Mn(III)N(shi))-5]. The metallacrown core consists of five Mn(III) and five shi(-3) ligands. The 15-membered metallacrown ring is formed by the succession of five structural moieties of the type [Mn(III)-N-O]. The diversity in the configuration (planar or propeller) for the ring Mn(III) ions gives to the metallacrown core flexibility and simultaneously allows the encapsulation of the sixth Mn(II). The encapsulated Mn(II) is seven-coordinate and is bound to the five hydroximate oxygen donors provided by the metallacrown core, and two oxygen atoms from the carboxylate herbicide ligands. Antibacterial screening data showed that among all the compounds tested, manganese metallacrowns are more active than the simple manganese herbicide or carboxylate complexes while an increase in the efficiency of [15-MC(Mn(III)N(shi))-5] towards the analogous [12-MC(Mn(III)N(shi))-4] can be observed.

Synthesis, characterization and evaluation of copper based nanoparticles as agrochemicals against Phytophthora infestans

Copper based nanoparticles (Cu-based NPs) of different composition and sizes have been hydrothermally synthesized by varying the reaction temperature and in the presence of biocompatible surfactants; polyoxyethylene (20) sorbitan laurate, polyethylene glycol 1000 and polyethylene glycol 8000. Effective control of the above synthetic parameters gave rise to Cu-based NPs of 11–55 nm. CuO, Cu2O nanoparticles and Cu/Cu2O composite nanoparticles of nearly similar size and shape were selected among the isolated samples and tested in the field on tomato (Lycopersicon esculentum) plants against Phytophthora infestans. Their activity has been evaluated by assessing the fungal infection on the leaves in comparison to the performance of the registered commercially used copper based products Kocide 2000, Kocide Opti, Cuprofix disperss and Ridomil Gold Plus. The results showed that the prepared Cu-based NPs can be applied in a lower formulated product and active ingredient rate and are more effective than the trade agrochemicals. Moreover, assessments regarding phytotoxicity indicated that they can be used without any deleterious effect on plants.

Pseudohalide complexation by manganese 12-metallacrowns-4 complexes

Abstract The reaction of manganese chloride, sodium or potassium thiocyanate and salicylhydroxamic acid in dimethylformamide–methanol solution leads to the formation of the 12-membered metallacrowns [Na(dmf)2]2(SCN)2{[12-MCMn(III)N(shi)-4](dmf)4} (1) and [K(dmf)2]2(SCN)2{[12-MCMn(III)N(shi)-4](dmf)4} (2). The crystal structure analyses of 1 and 2 show that pseudohalide ligands are bound to the ring manganese ions through the N atoms, while the alkaline ions, Na+ or K+, are accommodated at the cavity of the metallacrown ring. The alkali cations are bound to four oxygen atoms of the metallacrown ring and a single axial dmf. The binding of the pseudohalides (SCN−, OCN− and N3−) to the manganese ions of the metallacrown ring is very similar to that observed previously for (NaBr)2 and (KBr)2 metallacrowns; however, unlike the previously described halide complexes, the thiocyante does not form a bridge between the ring and central metal ions. Furthermore, the pseudohalide ligands do not form a second bond to an adjacent metallacrown, thus, single metallacrowns are isolated rather than chains or columns. The affinity of thiocyanate for the metallacrown is approximately equal to chloride and significantly greater than bromide.

Hydrothermal synthesis of copper based nanoparticles: antimicrobial screening and interaction with DNA.

Copper based nanoparticles (Cu-based NPs) of different compositions and sizes have been hydrothermally synthesized by varying the reaction time in the presence of the biocompatible surfactants polyoxyethylene (20) sorbitan laurate (Tween 20) and polyethylene glycol 8000 (PEG 8000). Effective control of the above synthetic parameters gave rise to Cu, Cu2O and Cu/Cu2O NPs of 10-44 nm. The antibacterial activity of the NPs was screened against Gram-positive (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus) and Gram-negative (Xanthomonas campestris, Escherichia coli) bacteria. The Cu-based NPs induce pDNA degradation in a dose-dependent manner as well as extensive ds CT-DNA degradation. Cu2O NPs of 16 nm and 12 nm exhibit the lowest IC50 values (2.13 μg/mL and 3.7 μg/mL) against B. cereus and B. subtilis, respectively. The agarose gel electrophoresis of ds CT-DNA treated with Cu2O NPs demonstrated degradation at high concentration. In lower concentrations, viscosity measurements indicated groove binding. In regard to the enhanced antibacterial effect and specificity of Cu2O NPs against the Gram-positive strains, the activity pathway was further explored and ROS production and lipid peroxidation verified. The released copper ions 5.15 mg/L in distilled water and 16.32 mg/L in nutrient medium, found below the critical value to inhibit bacterial growth and thus nanosized composition effect is predominant.

Selective Synthesis of Cu2O and Cu/Cu2O NPs: Antifungal Activity to Yeast Saccharomyces cerevisiae and DNA Interaction

A facile selective synthesis of Cu2O and heterogeneous Cu/Cu2O nanoparticles (NPs) was achieved through a solvothermal approach by Cu(NO3)2 in proportion of three different surfactants, namely, tetraethylene glycol (TEG), oleylamine (OAm) and polyoxyethylene (20) sorbitan laurate (Tween 20). Formation aspects for the spherical Cu2O@OAm (30 nm) and Cu2O@Tween (12 nm) as well as for the core-shell and semishell Cu/Cu2O@TEG NPs (7 nm) and the Cu/Cu2O@OAm (170 nm) nanorods have been proposed. The fungistatic and fungicidal activity of the newly synthesized NPs was studied in vitro against the yeast Saccharomyces cerevisiae, which constitutes a unicellular eukaryotic model microorganism in molecular and cell biology. The antifungal results, based on optical density and fluorescence measurements, clearly indicate that the composition, size, and amount of surfactant are of key importance in the antifungal properties of the NPs. Cu2O@OAm NPs exhibited the most prominent antifungal activity with 3.73 μg/mL IC(50viability) value. The isolated DNA of S. cerevisiae cells after exposure to the NPs was investigated, and binding and/or degradation phenomena were recorded that are correlated to the size and concentration of the NPs. Their activity pathway was further explored, and reactive oxygen species production and lipid peroxidation were verified mainly for Cu2O NPs.