Synthesis, structural characterization and study of antioxidant and anti-PrPSc properties of flavonoids and their rhenium(I)-tricarbonyl complexes.

This study aims at the synthesis and initial biological evaluation of novel rhenium-tricarbonyl complexes of 3,3',4',5,7-pentahydroxyflavone (quercetin), 3,7,4΄-trihydroxyflavone (resokaempferol), 5,7-dihydroxyflavone (chrysin) and 4΄,5,7-trihydroxyflavonone (naringenin) as neuroprotective and anti-PrP agents. Resokaempferol was synthesized from 2,2΄,4-trihydroxychalcone by H2O2/NaOH. The rhenium-tricarbonyl complexes of the type fac-[Re(CO)3(Fl)(sol)] were synthesized by reacting the precursor fac-[Re(CO)3(sol)3]+ with an equimolar amount of the flavonoids (Fl) quercetin, resokaempferol, chrysin and naringenin and the solvent (sol) was methanol or water. The respective Re-flavonoid complexes were purified by semi-preparative HPLC and characterized by spectroscopic methods. Furthermore, the structure of Re-chrysin was elucidated by X-ray crystallography. Initial screening of the neuroprotective properties of these compounds included the in vitro assessment of the antioxidant properties by the DPPH assay as well as the anti-lipid peroxidation of linoleic acid in the presence of AAPH and their ability to inhibit soybean lipoxygenase. From the above studies, it was concluded that the complexes' properties are mainly correlated with the structural characteristics and the presence of the flavonoids. The flavonoids and their respective Re-complexes were also tested in vitro for their ability to inhibit the formation and aggregation of the amyloid-like abnormal prion protein, PrPSc, by employing the real-time quaking-induced conversion assay with recombinant PrP seeded with cerebrospinal fluid from patients with Creutzfeldt-Jakob disease. All the compounds blocked de novo abnormal PrP formation and aggregation.

Iron(III) Complexes with Non-Steroidal Anti-Inflammatory Drugs: Structure, Antioxidant and Anticholinergic Activity, and Interaction with Biomolecules.

One the main research goals of bioinorganic chemists is the synthesis of novel coordination compounds possessing biological potency. Within this context, three novel iron(III) complexes with the non-steroidal anti-inflammatory drugs diflunisal and diclofenac in the presence or absence of the nitrogen donors 1,10-phenanthroline or pyridine were isolated and characterized by diverse techniques. The complexes were evaluated for their ability to scavenge in vitro free radicals such as hydroxyl, 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals, revealing their selective potency towards hydroxyl radicals. The in vitro inhibitory activity of the complexes towards the enzymes acetylcholinesterase and butyrylcholinesterase was evaluated, and their potential to achieve neuroprotection appeared promising. The interaction of the complexes with calf-thymus DNA was examined in vitro, revealing their ability to intercalate in-between DNA nucleobases. The affinity of the complexes for serum albumins was evaluated in vitro and revealed their tight and reversible binding.

Structural Speciation of Ti(IV)-(α-Hydroxycarboxylic Acid) Complexes in Metabolism-Related (Patho)Physiology-In Vitro Approaches to (Pre)Adipocyte Differentiation and Mineralization.

The prospect of developing soluble and bioavailable Ti(IV) complex forms with physiological substrates, capable of influencing (patho)physiological aberrations, emerges as a challenge in the case of metabolism-related pathologies (e.g., diabetes mellitus 1 and 2). To that end, pH-specific synthetic efforts on binary Ti(IV)-(α-hydroxycarboxylic acid) systems, involving natural physiological chelator ligands (α-hydroxy isobutyric acid, D-quinic acid, 2-ethyl-2-hydroxybutyric acid) in aqueous media, led to the successful isolation of binary crystalline Ti(IV)-containing products. The new materials were physicochemically characterized by elemental analysis, FT-IR, TGA, and X-ray crystallography, revealing in all cases the presence of mononuclear Ti(IV) complexes bearing a TiO6 core, with three bound ligands of variable deprotonation state. Solution studies through electrospray ionization mass spectrometry (ESI-MS) revealed the nature of species arising upon dissolution of the title compounds in water, thereby formulating a solid-state-solution correlation profile necessary for further employment in biological experiments. The ensuing cytotoxicity profile (pre-adipocytes and osteoblasts) of the new materials supported their use in cell differentiation experiments, thereby unraveling their structure-specific favorable effect toward adipogenesis and mineralization through an arsenal of in vitro biological assays. Collectively, well-defined atoxic binary Ti(IV)-hydroxycaboxylato complexes, bearing bound physiological substrates, emerge as competent inducers of cell differentiation, intimately associated with cell maturation, thereby (a) associating the adipogenic (insulin mimetic properties) and osteogenic potential (mineralization) of titanium and (b) justifying further investigation into the development of a new class of multipotent titanodrugs.

Inhibition of Cancer Cell Proliferation and Bacterial Growth by Silver(I) Complexes Bearing a CH3-Substituted Thiadiazole-Based Thioamide.

Ag(I) coordination compounds have recently attracted much attention as antiproliferative and antibacterial agents against a wide range of cancer cell lines and pathogens. The bioactivity potential of these complexes depends on their structural characteristics and the nature of their ligands. Herein, we present a series of four Ag(I) coordination compounds bearing as ligands the CH3-substituted thiadiazole-based thioamide 5-methyl-1,3,4-thiadiazole-2-thiol (mtdztH) and phosphines, i.e., [AgCl(mtdztH)(PPh3)2] (1), [Ag(mtdzt)(PPh3)3] (2), [AgCl(mtdztH)(xantphos)] (3), and [AgmtdztH)(dppe)(NO3)]n (4), where xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene and dppe = 1,2-bis(diphenylphosphino)ethane, and the assessment of their in vitro antibacterial and anti-cancer efficiency. Among them, diphosphine-containing compounds 3 and 4 were found to exhibit broad-spectrum antibacterial activity characteristics against both Gram-(+) and Gram-(-) bacterial strains, showing high in vitro bioactivity with IC50 values as low as 4.6 µΜ. In vitro cytotoxicity studies against human ovarian, pancreatic, lung, and prostate cancer cell lines revealed the strong cytotoxic potential of 2 and 4, with IC50 values in the range of 3.1-24.0 µΜ, while 3 and 4 maintained the normal fibroblast cells' viability at relatively higher levels. Assessment of these results, in combination with those obtained for analogous Ag(I) complexes bearing similar heterocyclic thioamides, suggest the pivotal role of the substituent groups of the thioamide heterocyclic ring in the antibacterial and anti-cancer efficacy of the respective Ag(I) complexes. Compounds 1-4 exhibited moderate in vitro antioxidant capacity for free radicals scavenging, as well as reasonably strong ability to interact with calf-thymus DNA, suggesting the likely implication of these properties in their bioactivity mechanisms. Complementary insights into the possible mechanism of their anti-cancer activity were provided by molecular docking calculations, exploring their ability to bind to the overexpressed fibroblast growth factor receptor 1 (FGFR1), affecting cancer cells' functionalities.

Mixed-Metal and Mixed-Ligand Lanthanide Metal-Organic Frameworks Based on 2,6-Naphthalenedicarboxylate: Thermally Activated Sensitization and White-Light Emission.

Trivalent lanthanide ions (Ln3+) hold an exceptional position in the field of optoelectronic materials due to their atomic-like emission spectra and long luminescence lifetimes. Metal-organic frameworks (MOFs) and coordination polymers are particularly suited as luminescent materials due to their structural diversity and ease of functionalization both at bridging ligands and/or metal centers. In this contribution, we present a series of mixed-metal Ln3+/Eu3+ (Ln = La, Gd) and mixed-ligand (2,6-naphthalenedicarboxylate (ndc2-) and 4-aminonaphthalene-2,6-dicarboxylate (andc2-)) MOFs belonging to three different structural types, with emissions spanning most of the visible region, thereby constituting favorable materials for color tuning and white-light emission. We investigate the thermal stability and photophysical properties of the synthesized materials with regard to their metal and ligand doping levels and structural type, where we discuss excimer and monomer emission. The photophysical study, involving both steady-state and time-resolved luminescence measurements, allows us to discuss the possible energy migration and Eu3+ sensitization pathways that take place within these materials following ligand excitation. Low-temperature luminescence studies led us to determine the energies of the ligand-based excited states and investigate their participation in thermally activated energy transfer mechanisms within the studied lattices. We observe emission quantum yields of up to 87% for the Eu3+-doped materials, while their ligand- and metal-doped counterparts show decreased quantum yields of up to 17%. Finally, we attempt fine color tuning by carefully adjusting the doping levels to achieve yellow and white-light emission.

Detection and Sorption of Heavy Metal Ions in Aqueous Media by a Fluorescent Zr(IV) Metal-Organic Framework Functionalized with 2-Picolylamine Receptor Groups.

Increasing global environmental pollution due to heavy metal ions raises the importance of research on new multifunctional materials for simultaneous detection and removal of these contaminants from water resources. In this study, we report a microporous 8-connected Zr4+ metal-organic framework (MOF) based on a terephthalate ligand decorated with a chelating 2-picolylamine side group (dMOR-2), which shows highly efficient fluorescence sensing and sorption of heavy metal cations. We demonstrate by detailed fluorescence studies the ability of a water-dispersible composite of dMOR-2 with polyvinylpyrrolidone for real-time detection of Cu2+, Pb2+, and Hg2+ in aqueous media. The limits of detection were found to be below 2 ppb for these species, while the system's performance is not affected by the presence of other potentially competitive ions. In addition, sorption studies showed that a composite of dMOR-2 with calcium alginate (dMOR-2@CaA) is an excellent sorbent for Pb2+ and Cu2+ ions with capacities of 376 ± 15 and 117 ± 4 mg per gram of dMOR-2@CaA, respectively, while displaying the capability for simultaneous removal of various heavy metal ions in low initial concentrations and in the presence of large excesses of other cationic species. Structural and spectroscopic studies with model ligands analogous to our material's receptor unit showed chelation to the 2-picolylamine moiety to be the main binding mode of metal ions to dMOR-2. Overall, dMOR-2 is shown to represent a rare example of a MOF, which combines sensitive fluorescence detection and high sorption capacity for heavy metal ions.

Chromium Flavonoid Complexation in an Antioxidant Capacity Role.

The plethora of flavonoid antioxidants in plant organisms, widespread in nature, and the appropriate metal ions known for their influence on biological processes constitute the crux of investigations toward the development of preventive metallodrugs and therapeutics in several human pathophysiologies. To that end, driven by the need to enhance the structural and (bio)chemical attributes of the flavonoid chrysin, as a metal ion complexation agent, thereby rendering it bioavailable toward oxidative stress, synthetic efforts in our lab targeted ternary Cr(III)-chrysin species in the presence of auxiliary aromatic N,N'-chelators. The crystalline metal-organic Cr(III)-chrysin-L (L = bipyridine (1) and phenanthroline (2)) compounds that arose were physicochemically characterized by elemental analysis, FT-IR, UV-Visible, ESI-MS, luminescence, and X-ray crystallography. The properties of these compounds in a solid state and in solution formulate a well-defined profile for the two species, thereby justifying their further use in biological experiments, intimately related to cellular processes on oxidative stress. Experiments in C2C12 myoblasts at the cellular level (a) focus on the antioxidant capacity of the Cr(III)-complexed flavonoids, emphasizing their distinct antiradical activity under oxidative stress conditions, and (b) exemplify the importance of structural speciation in Cr(III)-flavonoid interactions, thereby formulating correlations with the antioxidant activity of a bioavailable flavonoid toward cellular pathophysiologies, collectively supporting flavonoid introduction in new metallo-therapeutics.

Copper(II) Complexes of 5-Fluoro-Salicylaldehyde: Synthesis, Characterization, Antioxidant Properties, Interaction with DNA and Serum Albumins.

The synthesis, characterization and biological profile (antioxidant capacity, interaction with calf-thymus DNA and serum albumins) of five neutral copper(II) complexes of 5-fluoro-salicylaldehyde in the absence or presence of the N,N'-donor co-ligands 2,2'-bipyridylamine, 2,9-dimethyl-1,10-phenanthroline, 1,10-phenanthroline and 2,2'-bipyridine are presented herein. The compounds were characterized by physicochemical and spectroscopic techniques. The crystal structures of four complexes were determined by single-crystal X-ray crystallography. The ability of the complexes to scavenge 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radicals and to reduce H2O2 was investigated in order to evaluate their antioxidant activity. The interaction of the compounds with calf-thymus DNA possibly takes place via intercalation as suggested by UV-vis spectroscopy and DNA-viscosity titration studies and via competitive studies with ethidium bromide. The affinity of the complexes with bovine and human serum albumins was examined by fluorescence emission spectroscopy revealing the tight and reversible binding of the complexes with the albumins.

Selective Reduction of Nitroarenes to Arylamines by the Cooperative Action of Methylhydrazine and a Tris(N-heterocyclic thioamidate) Cobalt(III) Complex.

We report an efficient catalytic protocol that chemoselectively reduces nitroarenes to arylamines, by using methylhydrazine as a reducing agent in combination with the easily synthesized and robust catalyst tris(N-heterocyclic thioamidate) Co(III) complex [Co(κS,N-tfmp2S)3], tfmp2S = 4-(trifluoromethyl)-pyrimidine-2-thiolate. A series of arylamines and heterocyclic amines were formed in excellent yields and chemoselectivity. High conversion yields of nitroarenes into the corresponding amines were observed by using polar protic solvents, such as MeOH and iPrOH. Among several hydrogen donors that were examined, methylhydrazine demonstrated the best performance. Preliminary mechanistic investigations, supported by UV-vis and NMR spectroscopy, cyclic voltammetry, and high-resolution mass spectrometry, suggest a cooperative action of methylhydrazine and [Co(κS,N-tfmp2S)3] via a coordination activation pathway that leads to the formation of a reduced cobalt species, responsible for the catalytic transformation. In general, the corresponding N-arylhydroxylamines were identified as the sole intermediates. Nevertheless, the corresponding nitrosoarenes can also be formed as intermediates, which, however, are rapidly transformed into the desired arylamines in the presence of methylhydrazine through a noncatalytic path. On the basis of the observed high chemoselectivity and yields, and the fast and clean reaction processes, the present catalytic system [Co(κS,N-tfmp2S)3]/MeNHNH2 shows promise for the efficient synthesis of aromatic amines that could find various industrial applications.

Toward Multifunctional Materials Incorporating Stepladder Manganese(III) Inverse-[9-MC-3]-Metallacrowns and Anti-Inflammatory Drugs.

The interaction of Mn(ClO4)2·6H2O with salicylaldoxime (H2sao) in the presence of nonsteroidal anti-inflammatory drug (NSAID) sodium diclofenac (Nadicl) or indomethacin (Hindo) leads to the formation of the hexanuclear Mn(III) clusters [Mn6(O)2(dicl)2(sao)6(CH3OH)6] (1) and [Mn6(O)2(indo)2(sao)6(H2O)4] (2) both characterized as stepladder inverse-9-metallacrown-3 accommodating dicl- or indo- ligands, respectively. When the interaction of MnCl2·4H2O with Nadicl or Hindo is in the absence of H2sao, the mononuclear Mn(II) complexes [Mn(dicl)2(CH3OH)4] (3) and [Mn(indo)2(CH3OH)4] (4) were isolated. The complexes were characterized by physicochemical and spectroscopic techniques, and the structure of complexes 1 and 2 was characterized by X-ray crystallography. Magnetic measurements (dc and ac) were carried out in order to investigate the nature of magnetic interactions between the magnetic ions and the overall magnetic behavior of the complexes.

Alkaline Earth Metal Ion/Dihydroxy-Terephthalate MOFs: Structural Diversity and Unusual Luminescent Properties.

Alkaline earth (group 2) metal ion organic frameworks (AEMOFs) represent an important subcategory of MOFs with interesting structures and physical properties. Five MOFs, namely, [Mg2(H2dhtp)2(µ-H2O)(NMP)4] (AEMOF-2), [Mg2(H2dhtp)1.5(DMAc)4]Cl·DMAc (AEMOF-3), [Ca(H2dhtp)(DMAc)2] (AEMOF-4), [Sr3(H2dhtp)3(DMAc)6]·H2O (AEMOF-5), and [Ba(H2dhtp)(DMAc)] (AEMOF-6) (H4dhtp = 2,5-dihydroxy-terepthalic acid; DMAc = N,N-dimethylacetamide; NMP = N-methylpyrrolidone), are presented herein. The reported MOFs display structural variety with diverse topologies and new structural features. Interestingly, AEMOF-6 is the first example of a Ba(2+)-H2dhtp(2-) MOF, and AEMOF-5 is only the second known Sr(2+)-H2dhtp(2-) MOF. Detailed photoluminescence studies revealed alkaline earth metal ion-dependent fluorescence properties of the materials, with the heavier alkaline earth metal ions exhibiting red-shifted emission with respect to the lighter ions at room temperature. A bathochromic shift of the emission was observed for the MOFs (mostly for AEMOF-3 and AEMOF-4) at 77 K as a result of excited state proton transfer (ESIPT), which involves an intramolecular proton transfer from a hydroxyl to an adjacent carboxylic group of the H2dhtp(2-) ligand. Remarkably, AEMOF-6 displays rare yellow fluorescence at room temperature, which is attractive for solid state lighting applications. To probe whether the alkaline earth metal ions are responsible for the unusual luminescence properties of the reported MOFs, the potential energy surfaces (PESs) of the ground, S0, and lowest energy excited singlet, S1, states of model complexes along the intramolecular proton transfer coordinate were calculated by DFT and TD-DFT methods.

Tetracycline: structural characterization and antimicrobial properties of its water-soluble di-anionic bi-sodium salt.

The new water-soluble di-anionic bi-sodium salt of tetracycline (TC), an antibiotic in clinical use, with the formula {[TC]2-[Na+(MeOH)(H2O)] [Na+]·(H2O)}n (TCNa) was synthesized. The compound was characterized by m.p., attenuated total reflectance-Fourier transform infra-red (ATR-FTIR) spectroscopy, and ultraviolet (UV) and proton nuclear magnetic resonance (1H NMR) spectroscopy in the solid state and in solution. The molecular weight (MW) was determined by cryoscopy. The crystal structure of TCNa was also determined by X-ray crystallography. The antibacterial activity of TCNa was evaluated against the bacterial species Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli), Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus) by means of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibition zones (IZs). Moreover, the ability of the compound to eradicate biofilm formation was also evaluated. The results are compared with those obtained for the commercially available drug TCH2. The in vitro and in vivo toxicities of TCNa were tested against human corneal epithelial cells (HCECs) and Artemia salina.

N-heterocyclic-carbene vs diphosphine auxiliary ligands in thioamidato Cu(I) and Ag(I) complexes towards the development of potent and dual-activity antibacterial and apoptosis-inducing anticancer agents.

Group 11 metal complexes exhibit promising antibacterial and anticancer properties which can be further enhanced by appropriate ligands. Herein, a series of mononuclear thioamidato Cu(I) and Ag(I) complexes bearing either a diphosphine (P^P) or a N-heterocyclic carbene (NHC) auxiliary ligand (L) was synthesized, and the impact of the co-ligand L on the in vitro antibacterial and anticancer properties of their complexes was assessed. All complexes effectively inhibited the growth of various bacterial strains, with the NHC-Cu(I) complex found to be particularly effective against the Gram (+) bacteria (IC50 = 1-4 µg mL-1). Cytotoxicity studies against various human cancer cells revealed their high anticancer potency and the superior activity of the NHC-Ag(I) complex (IC50 = 0.95-4.5 µΜ). Flow cytometric analysis on lung and breast cancer cells treated with the NHC-Ag(I) complex suggested an apoptotic cell-death pathway; molecular docking calculations provided mechanistic insights, proving the capacity of the complex to bind on apoptosis-regulating proteins and affect their functionalities.

Synergy of redox-activity and hemilability in thioamidato cobalt(III) complexes for the chemoselective reduction of nitroarenes to anilines: catalytic and mechanistic investigation.

Reduction of nitro-compounds to amines is one of the most often employed and challenging catalytic processes in the fine and bulk chemical industry. Herein, we present two series of mononuclear homoleptic and heteroleptic Co(III) complexes, i.e., [Co(LNS)3] and [Co(LNS)2L1L2]x+, respectively (x = 0 or 1, LNS = pyrimidine- or pyridine-thioamidato, L1/L2 = thioamidato, phosphine or pyridine), which successfully catalyze the transformation of nitroarenes to anilines by methylhydrazine. The catalytic reaction can be accomplished for a range of electronically and sterically diverse nitroarenes, using mild experimental conditions and low catalyst loadings, resulting in the corresponding anilines in high yields, with high chemoselectivity, and no side-products. Electronic and steric properties of the ligands play pivotal role in the catalytic efficacy of the respective complexes. In particular, complexes bearing ligands of high hemilability/lability and being capable of stabilizing lower metal oxidation-states exhibit the highest catalytic activity. Mechanistic investigations suggest the participation of the Co(III) complexes in two parallel reaction pathways: (a) coordination-induced activation of methylhydrazine and (b) reduction of nitroarenes to anilines by methylhydrazine, through the formation of Co(I) and Co-hydride intermediates.

Erbium(III) coordination compounds with substituted salicylaldehydes: Characterization and biological profile.

Five erbium(III) complexes with salicylaldehyde (saloH for 1), and mono- (5-X-saloH; X = NO2 and Me for 2 and 3, respectively) or di-substituted salicylaldehydes (3,5-diX-saloH; X = Cl and Br for 4 and 5, respectively) were synthesized and characterized by physicochemical and spectroscopic techniques and single-crystal X-ray crystallography. All five complexes have the general formula [Er(deprotonated salicylaldehyde)3(MeOH)(H2O)]. The structure of complexes [Er(3,5-diCl-salo)3(MeOH)(H2O)]·1.5MeOH (complex 4) and [Er(3,5-diBr-salo)3(MeOH)(H2O)]·1.75MeOH (complex 5) were verified by single-crystal X-ray crystallography. The evaluation of antioxidant activity of the complexes was focused on their ability to scavenge 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and to reduce H2O2. The interaction of the complexes with calf-thymus DNA was investigated by UV-vis spectroscopy, viscosity measurements and via competitive studies with ethidium bromide in order to evaluate the possible DNA-binding mode and to determine the corresponding DNA-binding constants. The affinity of the complexes for bovine and human serum albumins was explored by fluorescence emission spectroscopy and the corresponding binding constants were determined.

Copper(II) complexes with 3,5-dihalogeno-salicylaldehydes: Synthesis, structure and interaction with DNA and albumins.

Eight copper(II) complexes of 3,5-dichloro-salicyladehyde or 3,5-dibromo-salicyladehyde (3,5-diX-saloH, X = Br or Cl) were synthesized in the absence or presence of a N,N'-donor co-ligand such as 2,2'-bipyridylamine, 1,10-phenanthroline, or 2,2'-bipyridine. The resultant compounds were formulated as [Cu(3,5-diX-salo)2(MeOH)2] (1-2) and [Cu(3,5-diX-salo)(N,N'-donor)Cl] (3-8) and were characterized by diverse techniques. The crystal structures of three complexes were determined by single-crystal X-ray crystallography. Diverse techniques were employed in order to investigate the interaction of the complexes with calf-thymus DNA which showed intercalation as the most possible mode of their interaction. The affinity of the complexes for bovine serum albumin and human serum albumin was evaluated by fluorescence emission spectroscopy in order to calculate the binding constants which suggested a tight and reversible binding. SYNOPSIS: A series of copper(II) complexes with 3,5-dihalogen-substituted salicylaldehydes as ligands were isolated and characterized. In vitro biological studies showed the intercalation of the compounds with calf-thymus DNA and their tight and reversible binding with serum albumins.

Neutral and cationic nickel(II) complexes with substituted salicylaldehydes: Characterization, antibacterial activity, and interaction with biomacromolecules.

Four neutral and six cationic nickel(II) complexes of the substituted salicylaldehydes (X-diCl-saloH), namely 3,5-dichloro-salicylaldehyde (3,5-diCl-saloH) and 5-fluoro-salicylaldehyde (5-F-saloH), were synthesized in the absence or presence of the N,N'-donors 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (neoc), or 2,2'-bipyridylamine (bipyam) as co-ligands and were characterized by various techniques. The obtained complexes bear the general formulas [Ni(X-salo)2(H2O)2], [Ni(3,5-diCl-salo)2(neoc/phen)] and [Ni(X-salo)(N,N'-donor)2](PF6). The crystal structures of three complexes were determined by single-crystal X-ray crystallography revealing a bidentate coordination of the salicylaldehydes. The interaction of the compounds with calf-thymus DNA was studied by diverse techniques which revealed an intercalative interaction for the neutral complexes [Ni(X-salo)2(H2O)2] and [Ni(3,5-diCl-salo)2(neoc/phen)]and the co-existence of electrostatic interactions for the cationic complexes [Ni(X-salo)(N,N'-donor)2](PF6). The compounds bind tightly and reversibly to serum albumins. The antibacterial activity of the compounds was investigated against Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6633, Escherichia coli NCTC 29,212 and Xanthomonas campestris ATCC 1395 and the complexes bearing neoc as co-ligand proved the most potent.

Possible implementation of salicylate anions in lead detoxification.

The water-soluble coordination polymer of formula {[Pb(Sal)2(H2O)]n} (SaLead), was obtained from the reaction between Pb(NO3)2 and the potassium salt of salicylic acid (SalH), an anti-inflammatory drug, which is also use as food preservation, in cosmetics etc. The compound was characterized by melting point, Attenuated Total Reflectance-Fourier Transform Infra-Red (ATR-FTIR) spectroscopy and X-ray diffraction crystallography (XRD) in solid state and in solution by Ultra Violet (UV) and 1H NMR spectroscopies. The binding affinity of SalK to Pb(II) ions towards SaLead was determined in order to examine its possible implementation in lead detoxification. The in vitro non-toxic behaviour of SalK and its complex SaLead was evaluated against normal human fetal lung fibroblast cells (MRC-5). The corresponding IC50 values are 260 ± 13 and > 1600 µM respectively. The non-genotoxic in vitro activity of SaLead was confirmed with the micronucleus (MN) assay, while its in vivo non-toxicity behaviour was evaluated with Allium cepa and Artemia salina assays.

Transition metal(II) complexes with the non-steroidal anti-inflammatory drug oxaprozin: Characterization and biological profile.

A series of copper(II), nickel(II) and cobalt(II) complexes with the non-steroidal anti-inflammatory drug oxaprozin (Hoxa) have been synthesized and characterized by diverse techniques. The crystal structures of two copper(II) complexes, namely the dinuclear complex [Cu2(oxa)4(DMF)2] (1) and the polymeric complex {[Cu2(oxa)4]·2MeOH·0.5MeOH}2 (12) were determined by single-crystal X-ray diffraction studies. In order to evaluate in vitro the antioxidant activity of the resultant complexes, their scavenging ability towards 1,1-diphenyl-picrylhydrazyl (DPPH), hydroxyl and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals was investigated revealing their high effectiveness against these radicals. The binding of the complexes to bovine serum albumin and human serum albumin was examined and the corresponding determined albumin-binding constants showed a tight and reversible interaction. The interaction of the complexes with calf-thymus DNA was monitored by diverse techniques including UV-vis spectroscopy, cyclic voltammetry, DNA-viscosity measurements and competitive studies with ethidium bromide. Intercalation may be proposed as the most possible DNA-interaction mode of the complexes.

New Apoptosis Inducers Containing Anti-inflammatory Drugs and Pnictogen Derivatives: A New Strategy in the Development of Mitochondrial Targeting Chemotherapeutics.

{[Ag8(Mef)8(µ2-S,O-DMSO)2(µ2-O-DMSO)2(O-DMSO)8]·2(H2O)} (1), [Ag(Mef)(tpP)2] (2), [Ag(Mef)(tpAs)3] (3), and {2 [Ag(Mef)(tpSb)3] (DMSO)} (4) were obtained by the conjugation of mefenamic acid (MefH), a nonsteroidal anti-inflammatory drug (NSAID), with a mitochondriotropic derivative of pnictogen tpE (tp = triphenyl group; E = P, As, and Sb) through silver(I). Their hydrophilicity was adjusted by their dispersion into sodium lauryl sulfate (SLS), forming SLS@1-4. 1-4 and SLS@1-4 were characterized by their spectral data and X-ray crystallography. They inhibit the proliferation of human breast adenocarcinoma cells MCF-7 (hormone-dependent (HD)) and MDA-MB-231 (hormone-independent (HI)). X-ray fluorescence reveals the Ag cellular uptake. The in vitro and in vivo nongenotoxicity was confirmed with micronucleus (MN), Artemia salina, and Allium cepa assays. Their mechanism of action was studied by cell morphology, DNA fragmentation, acridine orange/ethidium bromide (AO/EB) staining, cell cycle arrest, mitochondrial membrane permeabilization tests, DNA binding affinity, and LOX inhibitory activity and was rationalized by regression analysis.