Article
Chemistry, Organic
Thomas Rigotti, Thorsten Bach
Summary: This study presents a visible light-driven approach for the synthesis of Bicyclo[2.2.1]hexanes, and shows the possibility of further functionalization through consecutive reactions.
Article
Chemistry, Multidisciplinary
Tishyasoumya Bera, Bandana Singh, Vincent Gandon, Jaideep Saha
Summary: This study reveals a S-N'-type intramolecular aromatic substitution reaction that forms oxindoles by activating alpha-aryl-alpha-chlorohydroxamate. The investigation highlights the crucial role of HFIP in the transformation and suggests the operative pathway is a non-pericyclic nucleophilic amination.
CHEMISTRY-A EUROPEAN JOURNAL
(2022)
Article
Chemistry, Multidisciplinary
Julia M. Fehr, Nathalie Myrthil, Anna L. Garrison, Tavis W. Price, Steven A. Lopez, Ramesh Jasti
Summary: Tuning strained alkyne reactivity in organic synthesis is a growing field that focuses on cyclooctyne. Carbon nanomaterial research has produced new types of strained alkyne macrocycles, such as cycloparaphenyleneacetylenes, which have unique aromatic pi systems but are on the edge of stability. By combining synthetic accessibility and stability with curved pi systems, strained alkyne-containing cycloparaphenylenes ([n+1]CPPs) have been developed, showing size-dependent reactivity and classic characteristics of CPP. Modifications to the original design and the study of kinetics and computational models have further enhanced the properties and understanding of these carbon nanomaterials.
Article
Chemistry, Applied
Xu Zhao, Xiao-Ming He, Fen Liu, Chang-Qing Duan, Fei He
Summary: This study systematically elucidated the mechanism of intramolecular copigmentation in malvidin-3-O-(6-O-p-coumaryl)-glucoside, a type of acylated anthocyanin. The results showed that intramolecular copigmentation stabilized the anthocyanin and led to color changes. The conformational features and optical properties were analyzed using experimental and theoretical approaches.
Article
Chemistry, Physical
Anamarija Bris, Yasujiro Murata, Yoshifumi Hashikawa, Davor Margetic
Summary: Novel 2-pyridyl-sym-tetrazines bearing a guanidine functional group were synthesized and their reactivity was studied. Experimental and computational results showed that guanidine sym-tetrazines exhibit high reactivity towards strained polycyclic alkenes, while reactions with C-60 fullerene were less successful. These findings provide important insights into the cycloaddition reactivity and potential synthetic utility of tetrazine derivatives.
JOURNAL OF MOLECULAR STRUCTURE
(2023)
Article
Engineering, Mechanical
Xiao-Feng Geng, Hu Ding
Summary: This paper proposes an enhanced nonlinear energy sink (E-NES) design using piecewise linear springs to enhance vibration suppression effects. The design achieves better vibration suppression effects without changing the resonance frequency of the primary system. The parameters of the piecewise spring can be optimized efficiently using the differential evolution algorithm, and experiments show that the vibration elimination efficiency of the E-NES can exceed 90%.
NONLINEAR DYNAMICS
(2021)
Article
Spectroscopy
Imen Cherif, Hanen Raissi, Khouloud Abiedh, Bouzid Gassoumi, Maria Teresa Caccamo, Salvatore Magazu, Ayoub Haj Said, Fredj Hassen, Taoufik Boubaker, Sahbi Ayachi
Summary: This work focuses on investigating the high electrophilic character of 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) towards the morpholine group through an SNAr reaction in acetonitrile or water (referred to as NBD-Morph). The electron-donating ability of morpholine leads to intra-molecular charge transfer (ICT). UV-Vis, photoluminescence (cw-PL), and time-resolved photoluminescence (TR-PL) are used to comprehensively study the optical characteristics and properties of the emissive intramolecular charge transfer (ICT) in the NBD-Morph donor-acceptor system. The findings from theoretical investigations, including density functional theory (DFT) and its extension TD-DFT methods, provide valuable insights into the molecular structure and related properties, complementing the experimental results.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2023)
Article
Chemistry, Physical
Dinh Quy Huong, Mai Van Bay, Pham Cam Nam
Summary: The antioxidant abilities of thiourea derivatives were characterized by measuring the color change of DPPH and ABTS when reacting with the compounds. DPTU exhibited better free radical capture capability compared to BPTU, which was confirmed by quantum chemical calculations. Kinetic calculations revealed that hydrogen atom transfer mechanism is preferred over single electron transfer mechanism when thiourea derivatives react with free radicals, with HAT mechanism accounting for 99.99% of the product amount.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Polymer Science
Deepali Khokhar, Sapana Jadoun, Srivathsava Surabhi, D. V. Morales, Jong-Ryul Jeong
Summary: Copolymerization is an effective method to modify and enhance the optical and optoelectronic properties of selected monomers. This study utilized chemical oxidative polymerization to copolymerize o-phenylenediamine and thiophene, aiming to tune the optical properties. The experimental results showed that copolymerization could increase the oscillator strength and quantum yield, as well as improve the crystallinity and thermal stability of the material. These findings suggest the potential of this copolymer for various applications in optoelectronic devices.
EUROPEAN POLYMER JOURNAL
(2022)
Article
Construction & Building Technology
Kun Liang, Kun Feng, Li Zhang, Chuan He, Ang Su, Wenqi Guo
Summary: This study proposes a plastic hinge-based approach to investigate the failure mechanism of underwater shield tunnel lining structures. The study conducted full-scale tests on two types of shield tunnel lining structures: straight-joint assembly structure (STRJS) and staggered joint assembly structure (STGJS), and compared their failure mechanisms using the plastic hinge approach. The results showed that the assembly method significantly affected the failure pattern, and STRJS and STGJS failed through longitudinal joints and concrete segments, respectively. It highlights the importance of considering the assembly method and the type of plastic hinge in the design of underwater shield tunnel lining structures.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2023)
Article
Chemistry, Organic
Mateo Alajarin, Guillermo Cutillas-Font, Carmen Lopez-Leonardo, Raul-Angel Orenes, Marta Marin-Luna, Aurelia Pastor
Summary: This study presents the previously unknown intramolecular cyclization of a group of α-azido-ω-isocyanides in the presence of catalytic amounts of sodium azide. These compounds form tricyclic cyanamides [1,2,3]triazolo[1,5-a]quinoxaline-5(4H)-carbonitriles, while an excess of sodium azide leads to the formation of C-substituted tetrazoles through a [3 + 2] cycloaddition reaction. Experimental and computational methods were used to examine the formation of tricyclic cyanamides, revealing the presence of a long-lived N-cyanoamide anion that converts into the final cyanamide. The chemical behavior of these azido-isocyanides with an aryl-triazolyl linker was compared to that of a structurally identical azido-cyanide isomer. The synthetic procedures described in this work offer metal-free approaches to complex heterocyclic systems.
JOURNAL OF ORGANIC CHEMISTRY
(2023)
Article
Engineering, Environmental
Alessandro Stagni, Suphaporn Arunthanayothin, Luna Pratali Maffei, Olivier Herbinet, Frederique Battin-Leclerc, Tiziano Faravelli
Summary: Hydrogen sulfide chemistry has been gaining renewed attention due to the current energy transition and the need for proper treatment of impurities in sources like shale gas or biogas. Additionally, the development and validation of pyrolysis and oxidation mechanisms under lower-temperature, diluted conditions are crucial for reducing pollutant emissions.
CHEMICAL ENGINEERING JOURNAL
(2022)
Article
Biochemistry & Molecular Biology
Vladimir Chekanov, Anna Kovalenko
Summary: Magnetic fluid is a colloidal system with the distinctive feature of forming thin layers near the surface of electrodes when an electric field is applied. In this study, these layers are interpreted as a new type of liquid membrane and a physicochemical mechanism for the autowave process is proposed. A mathematical model is established and the dependence of concentration fluctuations on voltage and the formation time of the liquid membrane are obtained.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Chemistry, Multidisciplinary
Oriane Della-Negra, Brieuc Le Cacher de Bonneville, Sebastien Chaussonnerie, Denis Le Paslier, Gilles Frison, Pierre-Loic Saaidi
Summary: This study found that the sulfate-respiring bacterium Desulfovibrio sp.86 exhibited activity towards a variety of carbonyl substrates, and may involve two different mechanisms compared to chemical RS. Certain carbonyl substrates with electron-withdrawing groups and/or aromatic rings were directly transformed into thiols in the presence of P4S10, while Desulfovibrio sp.86 transformed multiple carbonyl substrates without detecting thiones.
Article
Chemistry, Organic
Zhichao Wang, Shoko Yamazaki, Yuji Mikata, Miho Oba, Hiroshi Takashima, Tsumoru Morimoto, Akiya Ogawa
Summary: Intramolecular cycloaddition reactions of α-bromostyr-ene-functionalized amides have been investigated, resulting in the formation of 1,4-dihydronaphthalenes and naphthalene derivatives under suitable reaction conditions. The mechanisms of these reactions may involve the intervention of molecular oxygen and subsequent radical reactions.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Tasnim Ahmed, Apurba De, Sumanta Paul, Anunay Samanta
Summary: By employing a combination of techniques, this study reveals individual particle-level understanding of charge carrier recombination pathways and dynamics in Bi-doped CsPbBr3 nanocrystals. The results show the heterogeneity of the system in terms of photoluminescence brightness/ efficiency of the individual nanocrystals in doped samples, with bright, dim, and dark types identified. The weak photoluminescence of the doped systems is mainly attributed to an ultrafast trapping process that turns a majority of the Bi-doped nanocrystals into dark ones.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Navendu Mondal, Apurba De, Sudipta Seth, Tasnim Ahmed, Somnath Das, Sumanta Paul, Rajesh Kumar Gautam, Anunay Samanta
Summary: The recent emergence of metal halide perovskites as triplet sensitizers has opened up new possibilities in optoelectronics. Understanding the band-edge energetics of perovskite nanocrystals, characterizing excitons, and investigating sensitization mechanisms of long-lived triplets are crucial in this area. Modulating deactivation processes in sensitized triplets for photon upconversion or room-temperature phosphorescence is also explored.
ACS ENERGY LETTERS
(2021)
Article
Chemistry, Physical
Sk Saddam Hossain, Sneha Paul, Anunay Samanta
Summary: The study investigates how deep eutectic solvents (DESs) affect the structural stability and conformational dynamics of cytochrome c, with a particular focus on the influence of trimethylglycine (TMG) combined with ethylene glycol (EG) or glycerol (GL). Single-molecule-based fluorescence correlation spectroscopy (FCS) and ensemble-based biophysical methods were employed to analyze the protein's behavior in hydrated DESs. The results suggest that the interaction strengths between DES constituents and water molecules play a crucial role in determining the behavior of cytochrome c in DESs.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Chemistry, Physical
Sumanta Paul, Tasnim Ahmed, Somnath Das, Anunay Samanta
Summary: This study demonstrates the direct synthesis of highly luminescent perovskite nanocrystals with PLQY as high as 80-99% by selecting appropriate halide precursors and optimizing the Pb:X precursor ratio. Time-resolved PL and ultrafast pump-probe studies reveal the impact of the Pb:X precursor ratio on carrier recombination processes. By using excess halide precursor, the carrier trapping effect that impairs PLQY can be effectively alleviated.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Physical
Rajesh Kumar Gautam, Somnath Das, Anunay Samanta
Summary: Studies have shown that cesium lead halide perovskite nanocrystals treated with sodium thiosulfate not only improve the photoluminescence quantum yield but also increase stability under different environmental stresses. This enhancement is achieved through the formation of Pb-S bonds between undercoordinated surface Pb and thiosulfate.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Rajesh Kumar Gautam, Somnath Das, Anunay Samanta
Summary: The treatment of blue-emitting, cyan-emitting, and green-emitting perovskite nanocrystals improves their photoluminescence quantum yield and stability, making them suitable for various lighting and display applications.
Article
Chemistry, Physical
Somnath Das, Anunay Samanta
Summary: The study presents a generic protocol for direct synthesis of iodide-based lead halide perovskite nanocrystals with extraordinary characteristics using 1,3-diiodo-5,5-dimethylhydantoin as iodide precursor. The synthesized nanocrystals exhibit phase purity, high photoluminescence quantum yield, and stability, which could be beneficial for efficient perovskite-based solar photovoltaic devices in the red-NIR region.
ACS ENERGY LETTERS
(2021)
Article
Chemistry, Physical
Tasnim Ahmed, Sumanta Paul, Anunay Samanta
Summary: Lead halide perovskites are crucial for solar photovoltaic applications, and understanding the hole transfer process is essential for their performance. This study investigates the influence of hole transfer from FAPbBr(3) to phenothiazine on the photoluminescence blinking dynamics of nanocrystals. The results reveal the heterogeneous nature of the hole transfer dynamics and the formation of a short-lived charge-separated state.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Physical
Sumanta Paul, Anunay Samanta
Summary: In this study, stable and highly luminescent CsPbI3 nanocrystals were successfully obtained by modifying the conventional hot-injection method with NH4I as an additional precursor. The excellent characteristics of these nanocrystals, such as the suppression of photoluminescence blinking, could be attributed to the replacement of surface Cs+ with NH4+ ions. These CsPbI3 nanocrystals show great potential for optoelectronic and solar photovoltaic applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Chemistry, Physical
Sumanta Paul, Gautam Kishore, Anunay Samanta
Summary: In this study, the photoluminescence blinking phenomenon of quantum confined CsPbBr3 nanocrystals with different sizes was investigated. The recombination pathways and dynamics of the photogenerated charge carriers were analyzed in both immobilized and fluid conditions. The results showed that smaller nanocrystals had a higher carrier trapping rate and a more difficult detrapping process. These findings provide valuable information for designing photoluminescent samples of CsPbBr3 nanocrystals for optoelectronic applications.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Carmelita Roda, Alessio Di Giacomo, Lucia Camila Tasende Rodriguez, M. Chandra Sekhar, Jari Leemans, Zeger Hens, Pieter Geiregat, Iwan Moreels
Summary: We synthesized CdSe/CdS nanoplatelets with 3.5 monolayers, which exhibit saturated blue emission and high photoluminescence quantum efficiency (PL QE) up to 55%. Compared to core-only nanoplatelets, the PL intensity decays exponentially due to suppressed deep trapping and delayed emission. Both core-only and core/crown nanoplatelets show biexciton-mediated optical gain between 470 and 510 nm, with higher gain coefficients in crowned nanoplatelets. However, the gain lifetimes are limited to 40 ps due to residual ultrafast trapping and higher exciton densities at threshold. These findings provide guidelines for optimizing CdSe nanoplatelets for lighting and light-amplification applications.
Article
Nanoscience & Nanotechnology
Somnath Das, Modasser Hossain, Anunay Samanta
Summary: A direct method of obtaining CsPbCl3 NCs with exceptional characteristics is reported using diphenylphosphoryl chloride as an efficient chloride precursor and preventing protonation of the amine ligand. High PLQY and remarkable stability of these NCs are attributed to the strong L-type coordination of the unprotonated amine ligand with Pb2+ on the surface. Using these NCs as emitting materials, a high-performance violet LED with ultrapure PL at 410 nm and narrow bandwidth is achieved.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Ramavath Babu, Anunay Samanta, Seelam Prasanthkumar, Lakshminarayana Polavarapu
Summary: In this study, hybrid Mn(II) halide (Cl, Br, and I) single crystals with near-unity photoluminescence quantum yield (PLQY) were prepared using the organic cation DMAPH and controlled Zn2+ doping/alloying. The PLQY of these crystals was stable for more than 60 days and could be improved by selective organic cations and doping/alloying strategies.
ACS MATERIALS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Somnath Das, Anunay Samanta
Summary: Direct synthesis of high-quality APbCl(3) and APbBr(3) nanocrystals has been achieved using the chloro- and bromo-analog of DIDMH, providing a generic approach for the synthesis of all APbX(3) nanocrystals. These nanocrystals exhibit excellent stability, high photoluminescence quantum yields, and remarkable performance under various conditions.
Article
Chemistry, Physical
Sumanta Paul, Anunay Samanta
Summary: By adding NH4I as a precursor, stable and highly luminescent CsPbI3 nanocrystals were successfully synthesized in this study, with significantly suppressed PL blinking. These CsPbI3 nanocrystals can be used as promising materials for single-photon emitters and optoelectronic and solar photovoltaic applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
