A5074183637- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Photosynthetic Processes and Mechanisms
- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Groundwater and Watershed Analysis
- Water Quality and Pollution Assessment
- Arsenic contamination and mitigation
- Water resources management and optimization
- Hydrology and Watershed Management Studies
- Electrocatalysts for Energy Conversion
- Heat Transfer Mechanisms
- Advanced Photocatalysis Techniques
- Fluid Dynamics and Turbulent Flows
- Water Quality Monitoring and Analysis
- Mitochondrial Function and Pathology
- Nanofluid Flow and Heat Transfer
- Heat Transfer and Optimization
- Heavy metals in environment
- Hydrological Forecasting Using AI
- Crystallography and molecular interactions
- Groundwater and Isotope Geochemistry
- Pharmaceutical and Antibiotic Environmental Impacts
- Catalytic C–H Functionalization Methods
- Catalytic Cross-Coupling Reactions
Jadavpur University
2012-2024
Yale University
2017-2022
University of New Haven
2017
Central Ground Water Board
2012
Peroxymonosulfate (HSO5– and PMS) is an optional bulk oxidant in advanced oxidation processes (AOPs) for treating wastewaters. Normally, PMS activated by the input of energy or reducing agent to generate sulfate hydroxyl radicals both. This study shows that without explicit activation undergoes direct reaction with a variety compounds, including antibiotics, pharmaceuticals, phenolics, commonly used singlet-oxygen (1O2) traps quenchers, specifically furfuryl alcohol (FFA), azide, histidine....
In this work, Ni(I) aryl species that are directly relevant to cross-coupling have been synthesized. Transmetalation of (dppf)NiIX (dppf = 1,1′-bis(diphenylphosphino)-ferrocene, X Cl, Br) with Grignard reagents or boronic acids in the presence base produces form (dppf)NiI(Ar) (Ar Ph, o-tolyl, 2,6-xylyl, 2,4,6-mesityl, 2,4,6-iPr3C6H2). The stability is inversely correlated steric bulk on ligand. most unstable active precatalysts for Suzuki–Miyaura reactions because they rapidly decompose...
Tandem dye-sensitized photoelectrosynthesis cells are promising architectures for the production of solar fuels and commodity chemicals. A key bottleneck in development these is low efficiency photocathodes, leading to small current densities. Herein, we report a new design principle highly active photocathodes that relies on outer-sphere reduction substrate from dye, generating an unstable radical proceeds desired product. We show direct dioxygen nickel oxide (NiO) leads H2O2. In presence...
The inertness of the C-H bond in CH4 poses significant challenges to selective oxidation, which often proceeds all way CO2 once activated. Selective oxidation high-value industrial chemicals such as CO or CH3OH remains a challenge. Presently, main methods activate include thermochemical, electrochemical, and photocatalytic reactions. Of them, reactions hold great promise for practical applications but have been poorly studied. Existing demonstrations exhibit limited control over product...
Water oxidation by photosystem II (PSII) involves the release of O2, electrons, and protons at oxygen-evolving complex (OEC). These processes are facilitated a hydrogen-bonded network amino acid residues waters surrounding OEC. It is crucial to probe proton-transfer pathways from OEC as proton helps maintain charge balance required for efficient water oxidation. In this study, we generate point mutations in cyanobacterium Synechocystis sp. PCC 6803 secondary-shell OEC: D2-K317, D1-S169,...
Coordination of redox-active ligands to metals is a compelling strategy for making reduced complexes more accessible. In this work, we explore the use formazanate in low-coordinate iron chemistry. Reduction an iron(II) precursor occurs at milder potentials than analogous non-redox-active β-diketiminate complexes, and three-coordinate formazanate-iron compound characterized detail. Structural, spectroscopic, computational analysis show that ligand undergoes reversible ligand-centered...
Since the discovery of molecular chirality, nonsuperimposable mirror-image organic molecules have been found to be essential across biological and chemical processes increasingly in materials science. Generally, carbon centers containing four different substituents are configurationally stable, unless bonds stereogenic atom broken re-formed. Herein, we describe sp3-stereogenic carbon-bearing that dynamically isomerize, interconverting between enantiomers without cleavage a constituent bond,...
There is currently significant interest in the development of efficient nickel precatalysts for cross-coupling. In this work, 14 nickel(II) form (dppf)Ni(aryl)(X) (dppf = 1,1′-bis(diphenylphosphino)ferrocene, X Cl, Br) were synthesized. particular, both electronic and steric properties aryl group modified to understand how affects precatalyst activation. Using EPR spectroscopy, it was demonstrated that amount off-cycle nickel(I) species which are formed via comproportionation during...
Photoinduced water oxidation at the O2-evolving complex (OEC) of photosystem II (PSII) is a process involving tetramanganese-calcium cluster that surrounded by hydrogen-bonded network molecules, chloride ions, and amino acid residues. Although structure OEC has remained conserved over eons evolution, significant differences in chloride-binding characteristics exist between cyanobacteria higher plants. An analysis residues around identified residue 87 D1 subunit as only difference PSII We...
In photosystem II (PSII), photosynthetic water oxidation occurs at the tetramanganese-calcium cluster that cycles through light-induced intermediates (S0-S4) to produce oxygen from two substrate waters. The surrounding hydrogen-bonded amino acid residues and waters form channels facilitate proton transfer delivery, thereby ensuring efficient oxidation. residue D1-S169 lies in "narrow" channel forms hydrogen bonds with Mn4CaO5 via W1 Wx. To probe role of narrow substrate-water binding, we...
Understanding hydrological processes is achieved using modeling approaches due to the extensive and complex interactions between various environmental elements. Hydrological based on empirical equations that require parameter calibration model validation improve performance evaluate results. This process requires implementation of absent or lacking data in many ungauged catchments. Therefore, Modeling Ungauged Catchments (HMUC) an important research area hydrology. Many researchers tried...
The second-shell ammonia binding sites near the OEC (oxygen-evolving complex) of PSII are characterized by combined Continuum Electrostatic/Monte Carlo (MCCE), QM/MM and DFT calculations compared with new earlier experimental measurements. MCCE shows has significant affinity at 6 positions but only two significantly influence OEC. Although pKa ammonium ion is 9.25, it calculated to bind as NH3, in agreement its low pH. also help explain experimentally observed competitive chloride. Ammonia...
Two-dimensional 13 C HYSCORE spectroscopy, in conjunction with QM/MM and DFT, indicates that methanol binds to the Mn 4 Ca-oxo cluster S 2 state of D1-N87A photosystem II from Synechocystis sp. PCC 6803.
The increasing stress on fresh water resources due to ever-rising demands and profligateuses as well growing population industrial establishment of Kolkata is an issue ofgreat concern. purpose this study make a quantitative estimate the availablegroundwater in eastern part for efficient utilization andmanagement groundwater resources. methodology involved investigation,drilling, lowering, collection analysis main observation wells data andgroundwater quality well. Based upon lithological...
This investigation intends to present a theoretical analysis, comparison and thermal optimization of rectangular microchannel heat sink cooling by TiO2-water ZnO-Water nanofluids.Nanofluids at volume fractions 1%, 2%, 4%, 6%, 8% 10% are applied evaluate enhance the performance sinks.Engineering Equation Solver (EES) is used for optimizing sink.The inclusion nanoparticles in base fluid consequences reduction resistance with concurrent growth inthe pumping power.The more intense ZnO-water...
The oxygen-evolving complex (OEC) of photosystem II (PSII) is an oxomanganese cluster composed four redox-active Mn ions and one redox-inactive Ca2+ ion, with two nearby bound Cl– ions. Sodium a common counterion both chloride hydroxide anions, sodium-specific binding site has not been identified near the OEC. Here, we find that oxygen-evolution activity spinach PSII increases Na+ concentration, particularly at high pH. A Na+-specific next to OEC, becomes available after deprotonation...