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Background: Infectious diseases still affect large populations causing significant morbidity and mortality. Bacterial and fungal infections for centuries were the main factors of death and disability of millions of humans. Despite the progress in the control of infectious diseases, the appearance of resistance of microbes to existing drugs creates the need for the development of new effective antimicrobial agents. In an attempt to improve the antibacterial activity of previously synthesized compounds modifications to their structures were performed. Methods: Nineteen thiazolidinone derivatives with 6-Cl, 4-OMe, 6-CN, 6-adamantan, 4-Me, 6-adamantan substituents at benzothiazole ring were synthesized and evaluated against panel of four bacterial strains S. aureus, L. monocytogenes, E. coli and S. typhimirium and three resistant strains MRSA, E. coli and P. aeruginosa in order to improve activity of previously evaluated 6-OCF3-benzothiazole-based thiazolidinones. The evaluation of minimum inhibitory and minimum bactericidal concentration was determined by microdilution method. As reference compounds ampicillin and streptomycin were used. Results: All compounds showed antibacterial activity with MIC in range of 0.12–0.75 mg/mL and MBC at 0.25–&gt, 1.00 mg/mL The most active compound among all tested appeared to be compound 18, with MIC at 0.10 mg/mL and MBC at 0.12 mg/mL against P. aeruginosa. as well as against resistant strain P. aeruginosa with MIC at 0.06 mg/mL and MBC at 0.12 mg/mL almost equipotent with streptomycin and better than ampicillin. Docking studies predicted that the inhibition of LD-carboxypeptidase is probably the possible mechanism of antibacterial activity of tested compounds. Conclusion: The best improvement of antibacterial activity after modifications was achieved by replacement of 6-OCF3 substituent in benzothiazole moiety by 6-Cl against S. aureus, MRSA and resistant strain of E. coli by 2.5 folds, while against L. monocytogenes and S. typhimirium from 4 to 5 folds.

Graphene oxide (GO)-based nanocomposites have received a great attention due to their emerging applications. Here, we thoroughly examined the structural, electronic and surface properties of $$\hbox {GO}/\hbox {TiO}_{2}$$ nanotubes nanocomposite. The nanocomposite is prepared by simple impregnation of $$\hbox {TiO}_{2}$$ nanotubes (HNT400) with GO dispersion. GO is elaborated by an improved Hummer’s method, while HNT400 is obtained using alkaline hydrothermal treatment of $$\hbox {TiO}_{2}$$ P25, followed by calcination at $$400^{\circ }\hbox {C}$$ . XRD and Raman analyses show that GO nanosheets do not change the structural properties of $$\hbox {TiO}_{2}$$ nanotubes. TEM analysis confirms the formation of GO nanosheets assembled to $$\hbox {TiO}_{2}$$ nanotubes. XPS and EPR results confirm the electron transfer between GO and $$\hbox {TiO}_{2}$$ nanotubes. PL analysis reveals that GO inhibits the recombination of photogenerated electron–hole pairs in the nanocomposite. The ac conductivity measurements suggest the presence of grain and grain boundary effects in GO/HNT400.

SSCI-VIDE+CARE:ECI2D+MHM:FDA:CGU:GBE; International audience; 1D nanotubular TiO2 are known to improve photocatalytic performance compared to classical 3D particles. Combination of TiO2 nanotubes (NTs) with graphene oxide (GO) was previously envisaged to limit the recombination of e--h+ pairs (Appl. Cat. B 2017, 209, 203-213). Compared to non-reduced GO, improvement in activity was noticed if partially reduced GO was used due to a decrease in charge transfer resistance after partial reduction limiting the recombination phenomenon. If GO was totally reduced, the gain in activity was lost suggesting that the driving force for the injection of electrons from TiO2 to GO comes from the consumption of oxygen groups on graphene layers. The present study proposes an alternative for avoiding the consumption of photoelectrons through the addition of Cu NPs onto GO without contact with TiO2 NTs. Such a building is facilitated by the tendency of GO to wrap up around TiO2 NTs. Comparison was herein performed between Cu/TiO2 NTs and Cu/(R)GO/NTs systems. On Cu/TiO2 NTs, results show a stabilization of Cu NPs at a +I oxidation state due to a strong interaction with TiO2 NTs leading to a 80% increase in activity for formic acid (FA) degradation under UV. TiO2 NTs are also necessary in combination with Cu to acquire an enhanced photocatalytic response in the visible region or for the production of H2. Contrary to GO/TiO2 NTs, in the presence of Cu, addition of non-reduced GO leads to a 250% increase in activity compared to TiO2 NTs alone for FA photodegradation while the use of partially reduced GO leads to a similar photocatalytic response than with Cu/TiO2 NTs alone. This effect is due to a partial dislocation of the graphene layers wrapped around TiO2 NTs leading to a preferential relocation of Cu NPs directly onto TiO2 NTs.

GO-TiO 2 photocatalysts were prepared using titanium dioxide (TiO 2 ) samples obtained by physical mixing of different amounts of anatase and rutile. The anatase/rutile mixtures were then supported by graphene oxide (GO) or reduced graphene oxide (rGO). The photocatalytic activity of these materials was investigated in the photodegradation of formic acid as a model reaction under UV/A light irradiation. (r)GO-TiO 2 samples containing both anatase and rutile phases show higher activities than pure anatase, the maximum being reached with 88% anatase and 12% rutile. This synergism observed between anatase and rutile is amplified when graphene oxide is added, particularly under its reduced form. This enhancing effect was explained mainly in terms of electron transfer from anatase to rutile and then to graphene oxide or reduced graphene oxide. In this respect, partial reduction of graphene oxide appears as a remarkable way to avoid recombination of photogenerated electron-hole pairs. However, interestingly, the charge transfer is efficient only if rutile is present in TiO 2 samples.

SSCI-VIDE+CARE:ECI2D+MHM:GBE:CGU:HKO; International audience; The influence on the photocatalytic performance of TiO2 nanotubes (NT) resulting from the addition of graphene oxide (GO) was studied. TiO2 nanotubes (NT) were prepared using alkaline hydrothermal treatment of TiO2 P25 followed by calcination at 400 C under air. GO-NT composites were then obtained by wet impregnation of the as-prepared TiO2 nanotubes onto graphene oxide before reduction under H2 at 200 C. In a first step, the influence of the reduction treatment was evaluated on GO alone to determine its role towards the nature of the oxygen-containing functional groups present. GO-NT composites were also characterized considering both the effect of the reduction treatment and of the GO weight loading on textural, structural, electronic, and optical properties of TiO2 nanotubes. The resulting GO-NT composites were finally evaluated for the photocatalytic degradation of formic acid and compared to TiO2 nanotubes alone and to P25. Results emphasize a strong increase of the electron affinity and conductivity of the GO-NT composites if graphene oxide is reduced at 200 degrees C. These enhanced properties lead to an easier separation of photogenerated charges and to a limitation of the recombination of electron-hole pairs. A dramatic gain in photocatalytic response is observed. Maximum in photocatalytic efficiency is reached at a GO loading of 1.0 wt% while further increase of GO weight loading blocks light penetration and depletes the photocatalytic response. (C) 2017 Elsevier B.V. All rights reserved.

SSCI-VIDE+CARE:ECI2D+MME:ATR:HKO:CGU:GBE; International audience; The influence of lanthanum on the thermal stability and photocatalytic activity of calcined hydrogenotitanate nanotubes (HNT) was hereinevaluated. HNT samples were prepared through the hydrothermal treatmentof TiO2 P25 in a concentrated NaOH solution (11.25 M) at 130 degrees Cduring 20 h followed by acid washing. La-doped titanates nanotubes(La-HNT) photocatalysts with optimum 1 wt% of La were then elaborated byincipient wetness impregnation method using lanthanum nitrate asprecursor. La HNT and HNT samples were then calcined at temperaturesvarying between 400 degrees C and 700 degrees C. Samples werecharacterized by means of nitrogen adsorption-desorption isotherms at77K, X-ray diffraction (XRD), Raman spectroscopy, diffuse reflectancespectroscopy (DRS), photoluminescence spectroscopy (PL), transmissionelectron microscopy (TEM), ICP analysis and photocurrent experiments.The photocatalytic activities of La-HNT and HNT derived nanomaterialswere then evaluated through the photocatalytic degradation of formicacid (FA).Main results reveal that lanthanum inhibits TiO2 crystallite growthand retards anatase transformation into the less active rutile phase.The addition of La ions to TiO2 results in a charge imbalance creating ahigh proportion of oxygen vacancies as evidenced by photocurrent,photoluminescence and Raman experiments.The photocatalytic experiments reveal that La-doped TiO2 helps tomaintain a high photocatalytic activity level even after calcination athigh temperatures contrary to La-free photocatalysts. The determinationof kinetic parameters reveals that the maintaining of a highphotocatalytic activity results from the synergetic effect betweenrestriction of TiO2 crystallite size growth and formation of a highproportion of oxygen vacancies.

SSCI-VIDE+ECI2D+GBE:HKO:GAN; International audience; Gold nanoparticles (NPs) with dendritic morphology were synthesized by a "green" seed-mediated approach in the presence of beta-cyclodextrin (beta-CD) as stabilizing biocompatible capping agent. First, 50 mL of an aqueous solution containing 5 mM of beta-CD were prepared, to which a variable amount of HAuCl4 was added. The beta-CD/Au molar ratio was monitored from 20 to 200. Optical properties, including Surface-Enhanced Raman Scattering (SERS) activity, of the synthesized structures were characterized by Raman and UV-vis spectroscopies. Morphology was studied by transmission electron microscopy (TEM). Samples prepared using this procedure presents an increase of their SERS signal with respect to samples without peak-rich morphology. Optimized nanodendrites were obtained at a beta-CD/Au molar ratio of 100. Moreover, a growth mechanism is proposed to describe the beta-cyclodextrin role in the synthesis of Au nanodendrites. The "green" seed-mediated synthesis technique used herein produces Au NPs with good biocompatibility pointing them out for biomedical applications.

[EN] One-pot deposition of Au onto TiO2 has been achieved through directly contacting gold (III) salt with nanosized functionalized TiO2 support initially obtained by sol-gel process using titanium isopropoxide and citric acid. Citrate groups act as functional moieties able to directly reduce the Au salt avoiding any further reducing treatment. Various gold salts (NaAuCl4 center dot 2H(2)O or HAuCl4 center dot 3H(2)O) and titanium to citrate (Ti/Cit) molar ratios (20, 50 and 100) were used in order to study the effect of the nature of the precursor and of the citrate content on the final Au particle size and catalytic properties of the as-obtained Au/TiO2 materials. Au/(TiO2)(x)(Cit)(1) catalysts characterization was performed using N-2 adsorption-desorption, ICP-AES, X-ray diffraction and TEM. The effect of the Ti/Cit molar ratio and of the gold precursor was evaluated. The selective oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) was studied as a model reaction. Kinetic analysis showed that the catalytic reaction rate was pseudo first-order and the values of activation energy have been reported. Results showed that the functionalization of TiO2 by citrate allows tuning the size of the Au nanoparticles deposited onto TiO2 as well as their morphology. Citrate also strongly enhances the benzyl alcohol oxidation through the control of the size and morphology of gold nanoparticles. (C) 2014 Elsevier B.V. All rights reserved., This work has been supported by the Instituto de Tecnologia Quimica (UPV-CSIC), Universidad Politecnica de Valencia-Consejo Superior de Investigaciones Cientificas, project number A/020411/08 et du Ministere Tunisien de l'Enseignement Superieur et de la Recherche Scientifique.

SSCI-VIDE+CARE:ECI2D+MME:HKO:GBE:CGU; International audience; In this work, the design of cerium doped TiO2 nanomaterials with tuned structural and textural properties is reported. The influence of the cerium content of doped TiO2 solids (x = 1 to 5 wt%) on the photocatalytic degradation of formic acid using UV-A light was evaluated.The best photocatalytic activity was reached for 1 wt% of cerium.The effect of post-thermal treatments was also herein highlighted by varying the calcination temperature between 400 degrees C and 700 degrees C for simultaneously doped- and cerium-free TiO2 samples. Characterization was performed by means of nitrogen adsorption-desorption isotherms at 77K, X-ray diffraction, Raman spectroscopy, Photoluminescence (PL) spectroscopy, and diffuse reflectance UV-vis spectroscopy. The presence of Ce limits the growth of TiO2 crystallite sizes during the post-thermal treatment and favors stabilization of the TiO2 anatase phase. The presence of cerium also increases the number of surface defects and transforms them to non-radiative centers able to capture the photogenerated electrons as observed by PL spectroscopy. This would leave photogenerated holes available improving consequentlythe photocatalytic activity for the oxidation of formic acid. Finally, a possible pathway mechanism is proposed to confirm the obtained results. (C) 2015 Published by Elsevier B.V.

SSCI-VIDE+CARE:ECI2D+MME:MHM:GBE:CGU:HKO; International audience; La-C-60/TiO2 nanocomposites were successfully obtained by dry impregnation method. The effect of La and polyhydroxylated fullerenolC-60(OH)n addition order onto TiO2 was carefully highlighted.Interesting photocatalytic activity was achieved for the materialfirstly added with lanthanum. The increase in photocatalytic activity isattributed mainly to the synergy between fullerenol and La. Fullerenolenhances the electron charge transfer; whereas La increases the TiO2thermal stability by adjusting the TiO2 crystallites sizes to low valuesand also by creating some structural defects.

SSCI-VIDE+CARE:ECI2D+MME:GBE:CGU:HKO; International audience; Lanthanum doped 1D-TiO(2)nanomaterials (nanorods and nanotubes) with tuned structural and textural properties have been evaluated in the photocatalytic degradation of formic acid (FA) under UV conditions. La-doped nanorods and nanotubes calcined at 973 K show interesting photocatalytic properties with respect to La-free nanomaterials. The presence of La inhibits TiO2 crystallite growth and increases the lifetime of photo-generated electron-hole pairs. (C) 2014 Elsevier B.V. All rights reserved.

AIR:EAU:RAFFINAGE:MATERIAUX+ATR:CGU:FDA:GBE:HKO; 1D-TiO2 nanomaterials (nanotubes, nanorods, nanoplates, nanospheres and nanoparticles) with tuned structural and textural properties have been evaluated in the photocatalytic degradation of formic acid (FA) under UV conditions. The FA adsorption isotherms follow the model of Langmuir and the kinetic of FA photodegradation shows Langmuir-Hinshelwood model whatever the TiO2 morphologies. TiO2 nanotubes (HTNT-400), nanoplates (HTNW-700) and nanoparticles (HTNT-500 and HTNT-600) show an interesting photocatalytic activities compared to TiO2 nanospheres (P25) and nanorods (TNR). The nanotubular TiO2 (HTNT-400) has a photocatalytic activity 4 times higher than TiO2 P25. The enhanced activity is attributed to the smaller crystallite size of anatase and tuned surface area of the photocatalyst. The pH study showed that the coexistence of HCOO- and HCOOH species at natural pH (ca. 3.5) is favourable for better adsorption on active sites of titanium oxide nanomaterials and consequently to a better photocatalytic activity. (C) 2014 Elsevier B.V. All rights reserved.

AIR:EAU:RAFFINAGE:MATERIAUX+HKO:CGU:GBE; Photocatalysis is a well known efficient process for the decontamination of wastewaters pollutants. In the last decade an intense research was focused on the elaboration of well tuned TiO2 photocatalysts with the basic idea to understand the relationship between exposed facet and reactivity. In this work, four TiO2 morphologies are examined namely: nanotubes (NT), nanoplates (NPL), nanorods (NR) and nanospheres (NS). The solar photocatalytic properties are compared in the disinfection of a Fusarium solani inoculated solution. Disinfection using the solar light has been studied and the effect of formic acid (FA) was examined. We demonstrated, for the first time, that the solar inactivation of the resistant spores of Fusarium in water is related to the exposed TiO2 facets. At very low concentration of photocatalyst, the inactivation of F. solani over TiO2 nanospheres shows the best disinfection efficiency with respect to the others morphologies. Experiments on simultaneous photocatalytic decontamination of FA and inactivation of F. solani showed that the presence of FA strongly retards the disinfection reaction in the case of TiO2 nanospheres while the FA degradation occurred simultaneously with F. solani inactivation in the case of TiO2 NT. This result shows the interest of TiO2 NT for the decontamination and disinfection of wastewaters containing acidic pollutants and pathogens. (C) 2012 Elsevier B.V. All rights reserved.

Shape-controlled silver and palladium nanoparticles were for the first time synthesized by seed-mediated techniques in the presence of β-cyclodextrin (β-CD). Palladium and silver seeds were prepared by reduction of palladium or silver ions with sodium borohydride in the presence of sodium citrate dihydrate as a stabilizer. Seeds were then injected into a "growth" solution containing the same Pd (or Ag) precursor, ascorbic acid (as a weak reducing agent), and β-CD. Using β-cyclodextrin impacts the final morphology of silver nanoparticles through a strong capping effect slowing down the growth regime and shifting it to thermodynamic-controlled conditions. Adjusting the β-CD/Ag molar ratio can lead to the selective formation of multiply twinned icosahedral particles presenting mainly {111} facets. On palladium, β-cyclodextrin selectively led to the controlled aggregation of primary nanoparticles into nanodendrites or multipods. After deposition on TiO 2 , these nanostructured Pd catalysts show excellent activity for the hydrogenation of cinnamaldehyde.

Hydrogenotitanates (HNTs) nanotubes with different diameters were prepared by hydrothermal treatment of TiO(2) (P25) followed by washing with HCl aqueous solution. The prepared samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermal analysis and N(2) adsorption/desorption. In order to determine the palladium uptake ability of different HNT samples, the interaction between HNTs and Pd(II) was subsequently studied in aqueous solution at pH 9 (NH(+)(4)/NH(3) buffer). Transmission electron microscopy showed that the diameter of the nanotubes depends on the preparation conditions. Chemical analysis of residual sodium and thermal studies showed that the chemical formula of the two prepared HNT was H(x)Na(2-x)Ti(2)O(5)H(2)O with x=1.61 or 1.65. The HNTs are mesoporous materials with a multi-walled nanotubular structure and high specific surface area. In order to determine the capacity of palladium retention of different HNTs samples, the interaction between HNTs and Pd(II) was subsequently studied in aqueous solution at pH 9 (NH(+)(4)/NH(3) buffer). The adsorption kinetics of Pd(II) on the HNTs was very fast. The isotherms of Pd(II) on the HNTs showed that the adsorption occurred (1) initially through cationic exchange and (2) when the concentration of Pd(II) is high by precipitation of different Pd salts. The adsorption capacity of Pd(II) is strongly altered by the morphology of the HNTs samples.

In spite of the controversy about the chemical structure and formation mechanism of hydrogenotitanates nanotubes (HNTs) through a basic hydrothermal treatment of TiO2, HNTs are still the subject of...

The Wadsworth-Emmons reactions, usually run in a stoichiometric mode with a high ratio base/substrate, can be achieved catalytically, minimizing the byproducts. Di-Et (cyanomethyl)phosphonate and tri-Et phosphonoacetate were reacted with different aldehydes on solid bases in batch conditions at 383 K. MgLa mixed oxide was found to be an efficient solid base for the selective synthesis of alpha,beta-unsatd. esters and nitriles with greater than 80% yields, and avoiding Knoevenagel condensation and aldolization even with aliph. aldehydes. The catalyst could be recycled once with high activity. The effect of substituents on the Ph ring of the aldehydes proves that the reaction proceeds via a base catalyzed mechanism with a low charge on intermediate species.

A series of Ti-silica mixed oxides were prepared using sol-gel polycondensation of Ti and Si alkoxydes. The polarity of the surface was changed by substituting partly tetraethoxysilane by phenyl or methyl triethoxysilane. This type of solid adsorbs much less water but moren-hexane than the mixed oxide obtained by the normal procedure; thus it shows hydrophobic character. From UV-vis and IR spectra, titanium is incorporated in the lattice of silica. Drying with supercritical carbon dioxide at low temperature produces a mesoporous solid which was used as catalyst for the reaction of cyclohexene with hydrogen peroxide ortert-butyl hydroperoxide (TBHP). The selectivity of epoxidation with TBHP is very high and reaches >95% in acetonitrile as solvent. In acetonitrile as solvent, the rate of epoxidation of cyclohexene with TBHP decreases when the polarity of the surface decreases, but the reverse effect is observed whentert-butanol is the solvent. The reaction with hydrogen peroxide (30% in water) produces both cyclohex-2-en-1-ol and epoxide by two parallel paths. In presence of an aprotic solvent the oxygen balance overpasses 100%, which means that radical reactions involving atmospheric oxygen are involved. The selectivity of the allylic attack leading to cyclohex-2-en-1-ol is sensitive to the nature of the solvent and is minimized intert-butanol. The epoxide is partly hydrolyzed to glycol, whatever the solvent and polarity of the surface. These catalysts epoxidize norbornene with high selectivity using hydrogen peroxide as oxidant.