RESUMEN
Our study aimed at acquiring information about the biological effect of pesticides and their degradates produced by UV-treatment on microbiological activity. Five photosensitive pesticides (carbendazim, acetochlor, simazine, chlorpyrifos, EPTC) and six representative soil microbes (Bacillus subtilis, Pseudomonas fluorescens, Mycobacterium phlei, Fusarium oxysporum, Penicillium expansum, Trichoderma harzianum) were applied throughout our model experiments. The antimicrobial effects of the pesticides and their degradates were assessed with filter paper disk method. The antimicrobial effect of the degradation products exhibited marked differences in terms of pesticide types, irradiation time, and the test organisms. Acetochlor and its photolytic degradation products were found to be more toxic to bacteria than fungi. All the three bacteria proved to be sensitive to the basic compound and its degradation products as well. The end product of carbendazim was weakly antibacterial against P. fluorescens and B. subtilis but strongly antifungal against T. harzianum. Chlorpyrifos and its end product inhibited neither test organisms, but the degradates hindered the growth of four of them. The basic compound of EPTC and the degradates of simazine exhibited significant toxicity to the test bacteria. It might be claimed that the pesticide photodegradation may result in significant changes in soil microbiota, as well as formation of biologically harmful degradates.
Asunto(s)
Antiinfecciosos/efectos de la radiación , Antiinfecciosos/toxicidad , Bacterias/efectos de los fármacos , Hongos/efectos de los fármacos , Plaguicidas/efectos de la radiación , Plaguicidas/toxicidad , Rayos Ultravioleta , Bacterias/crecimiento & desarrollo , Bencimidazoles/efectos de la radiación , Bencimidazoles/toxicidad , Carbamatos/efectos de la radiación , Carbamatos/toxicidad , Cloropirifos/efectos de la radiación , Cloropirifos/toxicidad , Hongos/crecimiento & desarrollo , Simazina/efectos de la radiación , Simazina/toxicidad , Microbiología del Suelo , Contaminantes del Suelo/efectos de la radiación , Contaminantes del Suelo/toxicidad , Tiocarbamatos/efectos de la radiación , Tiocarbamatos/toxicidad , Toluidinas/efectos de la radiación , Toluidinas/toxicidadRESUMEN
Charge-transfer (CT)-photolysis of Cu(II) dithiocarbamate mixed-ligand complexes Cu(II)(Et2dtc)X (X = Cl-, Br-) and Cu(II)(Et2dtc)(+)...Y- (Y = ClO4-, NO3-) has been studied in toluene/ROH and compared with our previous data obtained in chloromethane/ROH solutions, where chloromethane = CCl4, CHCl3 or CH2Cl2 and ROH = MeOH, EtOH, i-PrOH or i-BuOH. An EPR evidence is obtained about the formation of a new copper(II) dithiocarbamate mixed-ligand complex during simultaneous photolyses of Cu(II)(Et2dtc)+ and Cu(II)(Et2dtc)2 species in toluene/ROH. The role of the solvent is discussed from the combined analysis of spectrophotometric and EPR data and quantum yield results.
Asunto(s)
Alcoholes/química , Cobre/química , Fotólisis , Tiocarbamatos/química , Tolueno/química , Química Física/métodos , Espectroscopía de Resonancia por Spin del Electrón , Ligandos , Fotoquímica , Teoría Cuántica , Soluciones , Espectrofotometría , Tiocarbamatos/efectos de la radiaciónRESUMEN
The photocatalytic degradation of Cartap Hydrochloride, a synthetic pesticide. has been investigated over coated TiO2 photocatalysts irradiated with a ultraviolet (UV) light. The effect of operational parameters, i.e., Cartap Hydrochloride concentration, reaction time, light intensity and additive on the degradation rate of aqueous solution of Cartap Hydrochloride has been examined. Results show that the employment of efficient photocatalysts and the selection of optimal operational parameters may lead to degradation of Cartap Hydrochloride solutions.
Asunto(s)
Plaguicidas/química , Fotoquímica/métodos , Fármacos Fotosensibilizantes/farmacología , Tiocarbamatos/química , Titanio/farmacología , Catálisis , Cinética , Plaguicidas/efectos de la radiación , Tiocarbamatos/efectos de la radiación , Rayos UltravioletaRESUMEN
Chiropticenes are a novel class of predesigned chiral molecular switches that are triggered and controlled by a combination of both light and electric field. Chiropticenes contain an optically active (chiral) center and, as a consequence, provide two accessible equal energy bistable states resembling the molecular elements of binary logic. Structural engineering of the basic switch design is investigated to modulate the thermal and optical switching behavior of the resulting compounds. A simple screening methodology is presented to detect switching behavior in the solid state employing standard NMR and FT-IR spectroscopy. Validation of this method is demonstrated by the switching properties of newly synthesized anthraquinone dye based Chiropticenes. Functioning as a chiroptical dipole switch, Chiropticenes promise broad applications in emerging optoelectronic and molecular electronic technologies.
Asunto(s)
Computadores Moleculares , Electroquímica/instrumentación , Electrónica/instrumentación , Compuestos Heterocíclicos con 1 Anillo/química , Compuestos Heterocíclicos con 1 Anillo/efectos de la radiación , Nanotecnología/instrumentación , Óptica y Fotónica/instrumentación , Fotoquímica/instrumentación , Tiocarbamatos/química , Tiocarbamatos/efectos de la radiación , Electroquímica/métodos , Electrónica/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Miniaturización , Nanotecnología/métodos , Fotoquímica/métodosRESUMEN
As a result of radiolysis of sulfolane, that has a radioprotective action, sulfonyl anion-radicals and hydrosulfonyl radicals are produced, subsequent transformations of which lead to complete regeneration of sulfolane. On the other hand, some other five-membered cyclic sulfones, that have no radioprotective action, are irreversibly depleted in reactions with water radiolysis products. Sulfolane is suggested to protect from the effect of e(-)aq and H. and to be ineffective in protecting against OH. radicals.