The high mortality rate of candidemia and the limited option for the treatment of
spp. infection have been driving the search for new molecules with antifungal property. In this context, coordination ...complexes of metal ions and ligands appear to be important. Therefore, this study aimed to synthesize two new copper(II) complexes with 2-thiouracil and 6-methyl-2-thiouracil ligands and to evaluate their mutagenic potential and antifungal activity against
. The complexes were synthesized and characterized by infrared vibrational spectroscopy, CHN elemental analysis, UV-Vis experiments and ESI-HRMS spectrometry studies. The antifungal activity was evaluated by broth microdilution against 21 clinical isolates of
species. The mutagenic potential was evaluated by the Ames test. The complexes were Cu(Bipy)Cl₂(thiouracil) (Complex
) and Cu(Bipy)Cl₂(6-methylthiouracil) (Complex
). Complex
showed fungicidal and fungistatic activities against all isolates. Furthermore, the Minimum Inhibitory Concentration (MIC) from 31 to 125 µg/mL and inhibition percentage of 9.9% against the biofilms of
and
were demonstrated. At the concentrations tested, complex
exhibited no mutagenic potential. Complex
and the free ligands exhibited no antifungal activity at the concentrations evaluated. Since complex
presented antifungal activity against all the tested isolates and no mutagenic potential, it could be proposed as a potential new drug for anti-
therapy.
Due to the high pollution caused by several molecules, it is necessary to develop efficient materials to degrade these contaminants. Activated carbons (ACs) are exceptional and versatile adsorbents, ...and titanium dioxide (TiO2) has remarkable photocatalytic properties. The combination of activated carbon (AC) and TiO2 provides a system capable of simultaneously adsorbing and degrading several emerging contaminants. This study presents a new absorbent/photocatalyst material by modifying the AC with ethylenediamine (ET) and impregnated with TiO2 (AC-ET/TiO2). AC modified with amine groups keeps the TiO2 nanoparticles more bound onto its surface. A study exploring the dispersion onto the surface of unmodified AC revealed that the material lacked stability, releasing TiO2 particles into the solution. The characterization by nitrogen adsorption/desorption isotherms showed a mesoporous material that can have a synergic effect between the adsorption and photocatalysis. The photocatalyst was analyzed by field emission gun scanning electron microscopy (FEG-SEM) and demonstrated the presence of TiO2 dispersed on the surface. The AC-ET/TiO2 exhibited an improved photodegradation of sulfamethazine (SMT), superior to the commercial TiO2 – P25, by removing more than 90% of the SMT in 2 h of UV light irradiation. The reuse of the AC-ET/90TiO2 showed that this material is active after three photoreactions. In conclusion, amino groups insertion into AC is essential for the stability of the TiO2 on the surface. Besides, this material has increased photocatalytic activity with speedy degradation of SMT.
•Hybrid photocatalyst prepared AC, ethylenediamine, TiO2.•Removal of sulfamethazine under visible light using modified AC-ET/TiO2.•Combination AC and TiO2 provides a system capable of simultaneously adsorbing and degrading contaminants.•High sulfamethazine degradation onto AC-ET/TiO2.
CuO nanostructured thin films supported on silicon with 6.5 cm2 area (geometric area greater than the studies reported in the literature) were synthesized by a chemical bath deposition technique. The ...electrodes were characterized by MEV, XRD, XPS, contact angle, cyclic voltammetry and electrochemical impedance spectroscopy analyses. To evaluate the photoelectrochemical properties of the CuO films, photocurrent–voltage measurements were performed using linear voltammetry. The catalytic activities of CuO nanostructures were evaluated by monitoring photodegradation of Mitoxantrone (MTX) under UV-A light irradiation. The method of photoelectrocatalysis (PEC), applying a voltage of 1.5 V and assisted by adding H2O2, was undertaken. To the best of our knowledge, no studies on the degradation of anticancer agents using PEC process have been found in the literature. For comparison purposes, experiments were performed under the same conditions by assisted photocatalysis (PC) with H2O2 and direct photolysis. CuO deposits consist of a needle-like morphology. The presence of CuO in the tenorite phase was evidenced by XRD and the XPS spectra showed the presence of copper(II) oxide. The increase in current under illumination shows that CuO exhibits photoactivity. The PEC system showed a 75% level of MTX degradation, while the level achieved using PC was 50%. Under UV-A light alone only 3% removal was obtained after 180 min. Up to 10 by-products were identified by chromatography-mass spectrometry (LC-MS) with m/z values ranging between 521 and 285 and a plausible degradation route has been proposed. It is worth mentioning that 9 by-products identified in this work, were not found in the literature in other studies of degradation or products generated as metabolites. The toxicity tests of MTX before and after PEC treatment with Artemia Salina and Allium cepa showed a decrease in the acute toxicity of the medium as the antineoplastic was degraded.
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•Needle-like CuO nanostructures were grown on Si substrates using a CBD method.•High photoelectrocatalytic performance of CuO film is related to its needle-like nanostructure.•Enhanced H2O2-assisted PEC degradation by CuO film electrodes it was demonstrated.•The MTX drug exhibits high acute toxicity against Artemia salina and Allium cepa.•By-products generated by photoelectrocatalysis are substantially less toxic.
Metal-organic frameworks (MOFs) based on Fe exhibit great potential as highly effective photocatalysts for water treatment applications. TiO2 nanotube photoanodes decorated with 170–370 μg cm−2 of ...MIL-53(Fe) and Fe-MOF (i.e., melamine-modified MIL-53(Fe)) were synthesized and evaluated in the photoassisted electrochemical degradation of 2,4-dimethylaniline (2,4-DMA) under visible light irradiation. The morphological, optical, and electrochemical properties of the photoanodes were evaluated by SEM, TEM, FTIR, XPS, BET, PL, XRD, DRS, zeta potential, linear voltammetry, EIS, and Mott-Schottky technique, respectively. The absorption band of the carboxyl groups coordinated to the iron centers is observed by FTIR at 1550 cm−1, whereas a peak at 538 cm−1 is related the formation of metal-oxo bonds between the carboxylic group of terephthalic acid and Fe3+. The modification of MIL-53(Fe) through the insertion of melamine led to a reduction in the formed nanoparticles. The photoelectrochemical activity of MIL-53(Fe) at pH 3.0 was optimized using a central composite design (CCD) experimental plan, with H2O2 concentration, applied anode potential (Ean) and reaction time as variables under study. Upon addition of 10 mg L−1 H2O2, a degradation of 74.4% of 2,4-DMA was achieved at Ean = 1.0 V after 110 min, outperforming the 57% reached using an unmodified TiO2 nanotube photoanode. Further modification of the MIL-53(Fe) with melamine allowed obtaining an almost total degradation. A plausible degradation pathway for 2,4-DMA is discussed from NMR and HPLC-MS/MS results. This work demonstrates the promising photoelectrocatalytic activity of TiO2 photoanodes decorated with Fe-based MOFs.
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•TiO2 nanotube electrodes decorated with both pure MIL-53(Fe) and melamine-modified MIL-53(Fe) effectively remove 2,4-DMA.•Optimization of the PEF system variables is performed, and the results are satisfactory.•Melamine-modified MIL-53(Fe) exhibits higher photocatalytic activity.•Possible nitrocompounds are among the intermediates suggested by NMR analysis.
The photocatalytic activity of N-doped TiO2 nanoparticles to degrade metoprolol (MET) has been investigated. The materials were synthesized via sol-gel method and characterized using different ...techniques. All materials revealed the formation of anatase phase, with a band gap energy close to 3.12 eV, which suggests that the N doping did not cause substantial variations as compared to pure TiO2. However, the TiO2-5%N photocatalyst exhibited a reduction in nanoparticle size and a surface area 0.4-fold larger than undoped TiO2. The influence of pH, catalyst concentration, and doping percentage was investigated through a Box-Behnken experimental design. Under the best conditions (0.5 g L−1 of TiO2-5%N, solution pH 6.0), 98% MET degradation and 42% mineralization could be achieved, and the process by-products were non-toxic to Artemia salina.
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•Nitrogen doping promoted the formation of oxygen and Ti3+ surface defects in TiO2.•The system exhibited enhanced removal of refractory organic pollutants.•A Box-Behnken factorial design was employed as a statistical tool for metoprolol degradation.•Toxicity assessments with Artemia salina showed a satisfactory response to secondary effluent treatment enriched with MET.
This work describes the sonochemical synthesis, structural characterization, photophysical properties and preliminary in vitro antitumoral and antibacterial assays of new bioactive luminescent ...silver(I) complexes.
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•Sonochemical synthesis of new silver(I) luminescent materials.•Highly blue-greenish emission in solution and in the solid state upon excitation at 300 nm.•Cytotoxic studies demonstrated good selectivity to normal cells (BHK-21).•Promising antibacterial agents against resistant bacterial strains of S. aureus.
Novel mononuclear silver(I) complexes based on thiocarbamoyl-pyrazoline ligands were synthesized and structurally characterized. Complexes 1 and 2 were prepared in good yields using a sonochemical method. X-ray diffraction studies revealed trigonal coordination geometry for the AgI atom in complex 1 and distorted trigonal pyramidal geometry in complex 2, according to τ4 parameter analysis. Investigation of photophysical properties revealed intense blue-greenish emissions both in solution and in the solid state when excited at 300 nm. This emission was tentatively attributed to mixed (M+X)LCT and IL electronic transitions taking place after ligand metalation, as shown by DFT calculations. Complete characterization of the prepared compounds was also performed, including 1H and 13C NMR experiments, elemental analysis, infrared spectroscopy, absorption/emission studies, and time-resolved luminescence experiments. The synthesized ligands and complexes 1 and 2 were also tested as antibacterial agents against two standard bacterial strains (Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922) and a panel of clinical S. aureus strains with distinct antibiotic-resistance profiles. Antitumor activity was investigated against melanoma cells (B16F10) and mammary carcinoma cells (4T1).
This work presents the synthesis, characterization, and application of new CuI binuclear complexes as promising antitumoral and antibacterial compounds.
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Novel binuclear heteroleptic ...copper(I) complexes based on mixed DPPE /thiocarbamoyl-pyrazoline ligands were synthesized and structurally characterized. Accordingly, the X-ray studies the three prepared complexes belong to the monoclinic crystalline system. All complexes 1, 2, and 3 possess similar structural behavior around the Copper(I) atoms which presented a distorted tetrahedral coordination geometry determined by using the τ4 (tau four) parameter analysis. The complete characterization of the prepared compounds also included HRMS-ESI(+), NMR and elemental analyses, MID infrared, and UV-Vis spectroscopies. TD-DFT studies were also performed to support the assignments and interpretation of the main absorption bands observed in the UV-Vis experiments. The binuclear CuI complexes were assayed against a panel of antibiotic-resistant (MDR) bacteria (S. aureus) and S. pseudointermedius (MDR isolated from dog skin) showing promising MIC (7.8 to 62.5 µg/mL) and MBC (15.6 to 62.5 µg/mL) values. Additionally, the binuclear complexes were also tested as anticancer agents against tumoral cells B16F10 and 4T1 (metastatic murine melanoma and murine mammary carcinoma respectively) showing very low IC50 (0.16 to 0.6 µM) values.
The isophthaloylbis(N,N-diphenylthiourea) molecule (H2L ligand) reacts with CuI, CuII, MnIII, FeII, FeIII and CoII ions to form binuclear complexes with formula M2(L-O,S)2 (M = CuII (1), NiII (2)) or ...M2(L-O,S)3 (M = FeIII (4), CoIII (5)). In presence of dimethyl sulfoxide, Mn2(L-O,S)2(dmso)2 (3) was successfully obtained and represents the first manganese complex with any thiourea derivative ligand. The ligand and the complexes were characterized by spectroscopic techniques and elemental analysis. Complexes 1, 3, 4 and 5 were structurally analyzed by single crystal X-ray diffraction data, confirming the O,S chelating coordination mode. The stoichiometries were confirmed by thermal analysis with formation of the corresponding metal oxides. The set of the performed analysis corroborated that some metal ions undergo oxidation or reduction to form stable 2:2 or 2:3 metal to ligand stoichiometric complexes with H2L.
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•2:2 or 2:3 binuclear complexes formation by oxidation or reduction of metal ions.•First example of manganese binuclear complex with thiourea derivative ligand.•Spectroscopic, thermal and structural studies on binuclear thioureate compounds.•Flexibility of the chelate systems to provide stable coordination environments.
Candida spp. cause invasive fungal infections. One species, Candida glabrata, may present intrinsic resistance to conventional antifungal agents, thereby increasing mortality rates in hospitalized ...patients. In this context, metal complexes present an alternative for the development of new antifungal drugs owing to their biological and pharmacological activities demonstrated in studies in the last decades. Accordingly, in this study we have synthesized and characterized two new Co(II) complexes with thiocarbamoyl-pyrazoline ligands to assess their antimicrobial, mutagenic, and cytotoxic potential. For antimicrobial activity, the broth microdilution method was performed against ATCC strains of Candida spp. and fluconazole dose-dependent isolates of C. glabrata obtained from urine samples. The Ames test was used to assess mutagenic potential. The reduction method of the MTS reagent (3 4,5-dimethylthiazol-2-yl-5-3-carboxymethoxyphenyl-2-4-sulfophenyl-2H-tetrazolium) was performed with HeLa, SiHa, and Vero cells to determine cytotoxicity. Both complexes exhibited fungistatic and fungicidal activity for the yeasts used in the study, demonstrating greater potential for C. glabrata ATCC 2001 and the C. glabrata CG66 isolate with a Minimum Inhibitory Concentration MIC from 3.90 to 7.81 μg mL−1 and fungicidal action from 7.81 to 15.62 μg mL−1. The complexes inhibited and degraded biofilms by up to 90% and did not present mutagenic and cytotoxic potential at the concentrations evaluated for MIC. Thus, the complexes examined herein suggest promising alternatives for the development of new antifungal drugs.
Two new Co(II) complexes with thiocarbamoyl-pyrazoline ligands were synthesized and showed remarkable antifungal and antibiofilm activity against isolates of Candida species. Display omitted
•Two new Co(II) complexes with thiocarbamoyl-pyrazoline ligands were synthesized.•Both complexes showed greater potential against Candida glabrata.•The complexes inhibited and degraded biofilms by up to 90%.•Both complexes can be considered safe in terms of mutagenic and cytotoxic potential.•The complexes suggest promising alternatives for the development of new antifungal drugs.
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