612-27-1Relevant academic research and scientific papers
Lignin coating to quench photocatalytic activity of titanium dioxide nanoparticles for potential skin care applications
Morsella,Giammatteo,Arrizza,Tonucci,Bressan,D'Alessandro
, p. 57453 - 57461 (2015)
Ultraviolet light can cause photodamage to the skin, such as sunburns and melanomas. TiO2 is introduced in sunscreen formulations to reflect and scatter UV radiation. However, it can also photocatalyze the production of reactive species like O
Remote activation of nanoparticulate biomimetic activity by light triggered pH-jump
Wang, Xiaopei,Gong, Ao,Luo, Wenhao,Wang, Haiqing,Lin, Changxu,Liu, Xiang Yang,Lin, Youhui
, p. 8641 - 8644 (2018)
Herein, we report a facile, efficient and versatile method for the photo-regulation of pH-dependent activities of artificial enzymes by incorporating flash photolysis reagents. Under light excitation, a persistent pH shift is achieved by proton release fr
Photochemistry of o-Nitrobenzaldehyde and Related Studies
George, M. V.,Scaiano, J. C.
, p. 492 - 495 (1980)
Photolysis of solutions of o-nitrobenzaldehyde leads to the formation of o-nitrosobenzoic acid with quantum yields in the neighborhood of 0.5.The reaction proceeds via the intermediacy of a triplet state with a lifetime of 0.6 ns.A laser flash photolysis
Synthesis and photochemical studies of 2-nitrobenzyl-caged N-hydroxysulfonamides
Zhou, Yang,Bharadwaj, Vinay,Rahman, Mohammad S.,Sampson, Paul,Brasch, Nicola E.,Seed, Alexander J.
, (2019/09/09)
Recently, N-hydroxysulfonamides (RSO2NHOH) caged by photolabile protecting groups have attracted significant interest as potential photoactive nitroxyl (HNO) donors. The selectivity of the desired HNO generation pathway from photocaged N-hydroxysulfonamides versus a competing pathway involving O-N bond cleavage is dependent on the specific photodeprotection mechanism of the phototrigger. We present a new class of photocaged N-hydroxysulfonamides incorporating the well-established o-nitrobenzyl photoprotecting group, including a derivative incorporating an additional carbonate linker. Photodecomposition of o-NO2Bn-ON(H)SO2CF3 and the corresponding 2-nitro-4,5-dimethoxybenzyl analog generated the desired HNO and CF3SO2- as a minor pathway, with competing photoinduced O-N bond cleavage to release CF3SO2NH2 as the major photodecomposition pathway. Photolysis of the corresponding -SO2CH3 analogs resulted in O-N bond cleavage only. The presence of the o-nitro substituent was shown to be essential for photoactivity. Photorelease of the parent HNO donor CH3SO2NHOH was observed as the major product upon irradiation of o-NO2Bn-OC(O)ON(H)SO2CH3, with the desired HNO release and O-N bond cleavage occurring as minor pathways. Photoproduct quantum yields for each species have been determined by actinometry. The effect of solvent, pH and air on the mechanism of photodecomposition was studied for o-NO2Bn-ON(H)SO2CH3. The ratio of the solvents in the solvent mixture (CH3CN and phosphate buffer, pH 7.0), the pH of the aqueous component of the buffer, and the presence of oxygen did not affect the amount of each photoproduct and the observed rate constant for O-N bond cleavage. Possible mechanisms for the various pathways are proposed.
Investigating the Photochemistry of Spiropyran Metal Complexes with Online LED-NMR
Feuerstein, Thomas J.,Müller, Rouven,Barner-Kowollik, Christopher,Roesky, Peter W.
supporting information, p. 15479 - 15486 (2019/11/11)
As one of the best studied photoswitches, spiropyrans (SPs) have attracted significant interest in the scientific community. Among the many stimuli to alter the isomerization into the merocyanine (MC) isomer, such as temperature, pH, solvent polarity, redox potential, or mechanical force, the ability of the MC form to act as a ligand site for metal complexation has recently raised new attention. We herein synthesize hitherto undescribed coordination compounds of 8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro-[chromene-2,2′-indoline] with s-block ([Ca(MC)4](ClO4)2), d-block ([Zn(MC)2(MeCN)2](ClO4)2, [Ni(MC)2(MeCN)2](ClO4)2), as well as f-block ([La(NO3)3(MC)2]) metals. All complexes are structurally described by X-ray crystallography and systematically investigated in solution via Job's method of continuous variations (Job plots), as well as online NMR spectroscopic kinetic experiments with in situ irradiation of the analyte solution inside the NMR spectrometer (LED-NMR). We can unambiguously identify the photoresponsive nature of the complexes in solution, which is a crucial step toward the application of these promising molecules in material science.
Spectrophotometric Oxidative Decolorization of Methyl Red with Chloramine-T and Bromamine-T: Comparative Kinetic Modeling and Mechanistic Study
Adalagere Somashekar Manjunatha,Sukhdev, Anu,Puttaswamy
, p. 2647 - 2655 (2019/02/26)
Abstract: Methyl Red (MR) is a synthetic mono-azo dye which is extensively used as a colorant in textile and paper printing industries. The widespread amount of MR dye in wastewater poses potential threat to ecosystem and human health. In this context, we have developed a simple and expeditious oxidative decolorization technique for the removal of MR dye by organic N-haloamines viz., chloramine-T (CAT) and bromamine-T (BAT) present in the wastewater. The reaction was focused to changes in: (i) concentration of p-toluenesulfonamide, (ii) ionic strength, (iii) dielectric permittivity, (iv) polymerization study, and (v) halide ions effects. The activation parameters were deduced. Oxidation products of MR dye were identified. The rate of oxidation of MR is about four times faster with BAT than with CAT. The chemical oxygen demand value of the dye was determined. Phytotoxicity and economic analysis were carried out for the proposed decolorization process. A plausible mechanism conforming the kinetic data, reaction stoichiometry and product analysis has been proposed. Further, the present redox system can be adopted for treating MR dye present in industrial effluents with suitable modifications to reduce the toxicity caused by MR dye in wastewater.
Facile Quantum Yield Determination via NMR Actinometry
Ji, Yining,DiRocco, Daniel A.,Hong, Cynthia M.,Wismer, Michael K.,Reibarkh, Mikhail
supporting information, p. 2156 - 2159 (2018/04/30)
A simplified approach to quantum yield (φ) measurement using in situ LED NMR spectroscopy has been developed. The utility and performance of NMR actinometry has been demonstrated for the well-known chemical actinometers potassium ferrioxalate and o-nitrobenzaldehyde. A novel NMR-friendly actinometer, 2,4-dinitrobenzaldehyde, has been introduced for both 365 and 440 nm wavelengths. The method has been utilized successfully to measure the quantum yield of several recently published photochemical reactions.
Impact of vibrational excitation on the kinetics of a nascent ketene
Schmierer, Thomas,Schreier, Wolfgang J.,Koller, Florian O.,Schrader, Tobias E.,Gilch, Peter
experimental part, p. 11596 - 11607 (2010/06/15)
The formation and decay of a ketene intermediate photochemically formed from o-nitrobenzaldehyde has been studied by femtosecond UV/Vis and IR spectroscopy. The ketene is formed predominantly within a few 100 fs and to a minor extent within ～200 ps via th
Photochemical behavior of a new long-chain UV absorber derived from 4-tert-butyl-4′-methoxydibenzoylmethane
Wetz, Fabienne,Routaboul, Corinne,Lavabre, Dominique,Garrigues, Jean-Christophe,Rico-Lattes, Isabelle,Pernet, Ingrid,Denis, Alain
, p. 316 - 321 (2007/10/03)
A new UV filter, the 1-(4-tert-butylphenyl)-2-decanyl-3-(4′- methoxyphenyl)-propane-1,3-dione, called C10-DBM, was prepared by grafting a 10-carbon aliphatic chain to the α-carbonyl position of 4-tert-butyl-4′-methoxydibenzoylmethane (BM-DBM), a well-known and often used UV filter. The UV-A absorption efficiency of organic solutions containing the new filter was tested and compared with identical solutions containing BM-DBM with or without irradiation (xenon lamp). The originality of this new filter is that its UV-A absorbance appeared during irradiation of the molecule. Although the molar absorption coefficient of C01-DBM in the UV-A domain was lower than that of BM-DBM, the solutions absorption exhibited a much more photostable behavior under irradiation. In this study, we first demonstrated that C10-DBM was a precursor of BM-DBM (enol isomer) by means of high-performance liquid chromatography followed by mass spectrometry. Indeed, we showed that the UV-A absorption of C10-DBM solutions appearing during the irradiation of the molecule was due to a Norrish-II reaction (β-cleavage), which induced the release of the BM-DBM enol form and 1-decene. Then, we established a kinetic model for the photochemistry of C10-DBM and fitted the variation of UV absorption spectra to confirm the proposed mechanism.
An exceptionally stable Ti superoxide radical ion: A novel heterogeneous catalyst for the direct conversion of aromatic primary amines to nitro compounds
Dewkar, Gajanan K.,Nikalje, Milind D.,Ali, Iliyas Sayyed,Paraskar, Abhimanyu S.,Jagtap,Sudalai
, p. 405 - 408 (2007/10/03)
A matrix-bound superoxide radical anion, generated by treating Ti(OR)4 (R =iPr, nBu) with H2O2, is a selective heterogeneous catalyst for the oxidation of anilines to the corresponding nitroarenes with 50 % aqueous H2O2 [Eq. (1)]. Yields of 82-98 % are obtained, even with anilines bearing electron-withdrawing substituents (R = NO2, COOH).
