Read by QxMD icon Read

Green chemistry

Atanu Acharya, Alexey M Bogdanov, Bella L Grigorenko, Ksenia B Bravaya, Alexander V Nemukhin, Konstantin A Lukyanov, Anna I Krylov
Photoinduced reactions play an important role in the photocycle of fluorescent proteins from the green fluorescent protein (GFP) family. Among such processes are photoisomerization, photooxidation/photoreduction, breaking and making of covalent bonds, and excited-state proton transfer (ESPT). Many of these transformations are initiated by electron transfer (ET). The quantum yields of these processes vary significantly, from nearly 1 for ESPT to 10(-4)-10(-6) for ET. Importantly, even when quantum yields are relatively small, at the conditions of repeated illumination the overall effect is significant...
October 18, 2016: Chemical Reviews
John Lee
The molecular mechanisms of the bioluminescence systems of the firefly, bacteria, and those utilizing imidazopyrazinone luciferins such as coelenterazine, are gradually being uncovered using modern biophysical methods such as dynamic (ns-ps) fluorescence spectroscopy, NMR, X-ray crystallography, and computational chemistry. The chemical structures of all reactants are well defined and the spatial structures of the luciferases are providing important insight into interactions within the active cavity. It is generally accepted that the firefly and coelenterazine systems, although proceeding by different chemistries, both generate a dioxetanone high energy species that undergoes decarboxylation to form directly the product in its S1 state, the bioluminescence emitter...
October 17, 2016: Photochemistry and Photobiology
Samuel Bernard, Mirna Chaker Bechelany, Abhijeet Lale, Vanessa Proust, Philippe Miele, Sylvie Malo, Christel Gervais
Monolith-type titanium nitride/silicon nitride nanocomposites labelled TiN/Si3N4 were prepared by reaction of polysilazanes with titanium amide, warm-pressing of the resulting polytitanosilazanes and subsequent pyrolysis of the green bodies at 1400 °C. At first, a series of polytitanosilazanes was synthesized and the role of the chemistry behind their synthesis has been studied in details by solid-state NMR, elemental analyses and molecular weight measurements. The intimate relationship between the chemistry and the processability of the single-source precursors was discussed...
October 14, 2016: Chemistry: a European Journal
Ximena Fadic, Fabián Placencia, Ana María Domínguez, Francisco Cereceda-Balic
There is a current tendency to develop and apply environmentally friendly techniques that meet the requirements of green analytical chemistry as an alternative to conventional analytical methods. For toxicity evaluation, these alternatives may be found in bioassays such as Tradescantia. This technique, developed in the 1980s, is highly sensitive to evaluate environmental mutagens, simple and cheap. In this paper, the sensibility of both the Tradescantia micronucleus bioassay (Trad-MCN) and the Tradescantia stamen hair bioassay (Trad-SH) were studied for carbaryl, dimethoate and iprodione, common agricultural and domestic pesticides that are currently used in Chile, which have never been tested with such bioassays...
October 10, 2016: Science of the Total Environment
Sandrine Plumejeau, Matthieu Rivallin, Stephan Brosillon, André Ayral, Laurent Heux, Bruno Boury
Metal oxides and metal oxide/carbon composites are entering the development of new technologies and should therefore to be prepared by sustainable chemistry processes. Therefore, a new aspect of the reactivity of cellulose is presented through its solid/gas reaction with vapour of titanium(IV) chloride in anhydrous conditions at low temperature (80 °C). This reaction leads to two transformations both for cellulose and titanium(IV) chloride. A reductive dehydration of cellulose is seen at the lowest temperature ever reported and results in the formation of a carbonaceous fibrous solid as the only carbon-containing product...
October 13, 2016: Chemistry: a European Journal
R Milan, S Cattarin, N Comisso, C Baratto, K Kaunisto, N V Tkachenko, I Concina
The effect of a thin α-Fe2O3 compact buffer layer (BL) on the photoelectrochemical performances of a bare α-Fe2O3 nanorods photoanode is investigated. The BL is prepared through a simple spray deposition onto a fluorine-doped tin oxide (FTO) conducting glass substrate before the growth of a α-Fe2O3 nanorods via a hydrothermal process. Insertion of the hematite BL between the FTO and the nanorods markedly enhances the generated photocurrent, by limiting undesired losses of photogenerated charges at the FTO||electrolyte interface...
October 13, 2016: Scientific Reports
Stephen R Adams
Roger Y. Tsien, professor at the University of California, San Diego and Howard Hughes Medical Institute Investigator, passed away on August 24, 2016. Tsien shared the 2008 Nobel Prize in Chemistry for his work on the discovery and development of the green fluorescent protein, and developed a whole series of colored fluorescent proteins, as well as widely used small-molecule probes for Ca(2+) ions.
October 12, 2016: Angewandte Chemie
Samson Afewerki, Armando Córdova
The cooperation and interplay between organic and metal catalyst systems is of utmost importance in nature and chemical synthesis. Here innovative and selective cooperative catalyst systems can be designed by combining two catalysts that complement rather than inhibit one another. This refined strategy can permit chemical transformations unmanageable by either of the catalysts alone. This review summarizes innovations and developments in selective organic synthesis that have used cooperative dual catalysis by combining simple aminocatalysts with metal catalysts...
October 10, 2016: Chemical Reviews
T Montagnon, D Kalaitzakis, M Sofiadis, G Vassilikogiannakis
Very recent investigations are described, which have shown how basic and unprotected nitrogen functionalities can be included, problem-free, in the furan photooxidation step of singlet oxygen-initiated cascade reaction sequences. The amine groups do not react with singlet oxygen, but, instead, participate later on in the sequences that ultimately yield a diverse range of important alkaloid motifs. To illustrate the versatility of this chemistry, six natural products were synthesised very rapidly and efficiently...
September 21, 2016: Organic & Biomolecular Chemistry
Sambasivarao Kotha, Mohammad Saifuddin, Vikas R Aswar
New synthetic strategies to indolocarbazoles have been reported via two-fold Fischer indolization under green conditions using l-(+)-tartaric acid and N,N-dimethyl urea. Starting with cyclohexanone, a bench-top starting material, this methodology has been extended to the total synthesis of natural products such as tjipanazoles D and I as well as the core structure of asteropusazole and racemosin B. Here, atom economical reactions like ring-closing metathesis, enyne-metathesis, and the Diels-Alder reaction have been used as key steps...
October 18, 2016: Organic & Biomolecular Chemistry
Micheline Draye, Nathalie Kardos
Over the past 15 years, sustainable chemistry has emerged as a new paradigm in the development of chemistry. In the field of organic synthesis, green chemistry rhymes with relevant choice of starting materials, atom economy, methodologies that minimize the number of chemical steps, appropriate use of benign solvents and reagents, efficient strategies for product isolation and purification and energy minimization. In that context, unconventional methods, and especially ultrasound, can be a fine addition towards achieving these green requirements...
October 2016: Top Curr Chem (J)
Thomas Niederprüm, Oliver Thomas, Tanita Eichert, Carsten Lippe, Jesús Pérez-Ríos, Chris H Greene, Herwig Ott
Engineering molecules with a tunable bond length and defined quantum states lies at the heart of quantum chemistry. The unconventional binding mechanism of Rydberg molecules makes them a promising candidate to implement such tunable molecules. A very peculiar type of Rydberg molecules are the so-called butterfly molecules, which are bound by a shape resonance in the electron-perturber scattering. Here we report the observation of these exotic molecules and employ their exceptional properties to engineer their bond length, vibrational state, angular momentum and orientation in a small electric field...
October 5, 2016: Nature Communications
Dinesh Dhamecha, Sunil Jalalpure, Kiran Jadhav, Satveer Jagwani, Ramesh Chavan
The present work aims to investigate targeting potential of doxorubicin (Dox) functionalized gold nanoparticles (D-GNPs) for treatment of chemically induced fibrosarcoma in mice. Carrier GNPs were synthesised by green chemistry method and loaded with doxorubicin by incubation method. D-GNPs were studied for its biocompatibility using normal mouse fibroblasts (L929) and found to be cell compatible and non-toxic. D-GNPs (at a dose of 2.5, 2 and 1.5mg/kg equivalent to Dox) demonstrated passive targeting measured as function of antitumor efficacy against chemical induced fibrosarcoma which showed higher latency to the tumour growth as compared to free Dox (2...
September 28, 2016: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
Anna Żądło-Dobrowolska, Szymon Kłossowski, Dominik Koszelewski, Daniel Paprocki, Ryszard Ostaszewski
The application of the Ugi reaction to the construction of new peptide scaffolds is an important goal of organic chemistry. To date, there are no examples of the Ugi reaction being performed with a cyclic imine and amine simultaneously. The application of 2-substituted cyclic imines in an enzymatic three-component Ugi-type reaction provides an elegant and attractive synthesis of substituted pyrrolidine and piperidine derivatives in up to 60 % yield. Results on studies of the selection of an enzyme, amount of water, and solvent used in a novel three-component Ugi reaction and the limitations thereof are reported herein...
September 30, 2016: Chemistry: a European Journal
M Kątny, M Frankowski
Analytical methods should be selective and fast. In modern times scientists strive to meet the criteria of green chemistry, so they choose analytical procedures which are as short as possible and use the least toxic solvents. It is quite obvious that the products intended for human consumption should be characterized as completely as possible. The safety of a drug is dependent mainly on the impurities that it contains. High Pressure Liquid Chromatography and Ultra - High Pressure Liquid Chromatography have been proposed as the main techniques for forced degradation and impurity profiling...
September 29, 2016: Critical Reviews in Analytical Chemistry
Zequn Yan, Min Xue, Qian He, Wei Lu, Zihui Meng, Dan Yan, Lili Qiu, Lijun Zhou, Yingjie Yu
A novel polymerized crystalline colloidal array (PCCA) sensing material for the detection of urine glucose was developed by embedding a two-dimensional (2-D) polystyrene crystalline colloidal array (CCA) in 3-acrylamidophenylboronic acid (3-APBA)-functionalized hydrogel. After adjusting the cross-linker concentration, this material showed significant sensitivity for glucose under lab conditions, the particle spacing of the PCCA changed from 917 to 824 nm (93 nm) within 3 min as the glucose concentration increased from 0 to 10 mM, and the structural color of the PCCA changed from red through orange, to green, and finally, to cyan...
September 28, 2016: Analytical and Bioanalytical Chemistry
Konstantina Tsikrika, M Adília Lemos, Boon-Seang Chu, David H Bremner, Graham Hungerford
The application of ultrasound to a solution can induce cavitional phenomena and generate high localised temperatures and pressures. These are dependent of the frequency used and have enabled ultrasound application in areas such as synthetic, green and food chemistry. High frequency (100kHz to 1MHz) in particular is promising in food chemistry as a means to inactivate enzymes, replacing the need to use periods of high temperature. A plant enzyme, horseradish peroxidase, was studied using time-resolved fluorescence techniques as a means to assess the effect of high frequency (378kHz and 583kHz) ultrasound treatment at equivalent acoustic powers...
September 20, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Chiara Cabrele, Oliver Reiser
The synthesis of heterocycles is arguably one of the oldest and at the same time one of the youngest disciplines of organic chemistry. Groundbreaking principles to form heterocycles, mainly by condensation reactions, were recognized in the beginning of the 19th century, and many of the classical reactions discovered at that time are still of great value today. In the 21st century, the wealth of synthetic methodology toward heterocycles is overwhelming, and catalysis, in particular, as one of the cornerstones of green and sustainable chemistry has contributed in a major way to these developments...
October 10, 2016: Journal of Organic Chemistry
Spencer C Greene, Patrick K Noonan, Carlos Sanabria, W Frank Peacock
BACKGROUND: Oral solution N-acetylcysteine (NAC) is an antidote for acetaminophen overdose, but its unpleasant taste and aroma can impede delivery even after the coadministration of antiemetic medications. Flavored effervescent NAC tablets dissolved in water might be a more palatable formulation than oral solution NAC diluted with soft drink. OBJECTIVES: To evaluate the relative bioavailability of these 2 formulations and assess subjective preferences between them...
2016: Current Therapeutic Research, Clinical and Experimental
Belinda Soares, Helena Passos, Carmen S R Freire, João A P Coutinho, Armando J D Silvestre, Mara G Freire
Due to their unique properties, in recent years, ionic liquids (ILs) have been largely investigated in the field of analytical chemistry. Particularly during the last sixteen years, they have been successfully applied in the chromatographic and electrophoretic analysis of value-added compounds extracted from biomass. Considering the growing interest in the use of ILs in this field, this critical review provides a comprehensive overview on the improvements achieved using ILs as constituents of mobile or stationary phases in analytical techniques, namely in capillary electrophoresis and its different modes, in high performance liquid chromatography, and in gas chromatography, for the separation and analysis of natural compounds...
September 7, 2016: Green Chemistry: An International Journal and Green Chemistry Resource: GC
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"