Exploring the efficacy of some biologically active compounds as anti-hypertensive drugs: an insightful evaluation through DFT, molecular docking and molecular dynamics simulations.

Unlabelled: Among different anti-hypertensive drugs, calcium channel blockers and human angiotensin-converting enzyme (ACE) inhibitors are the two main types. Herein, we took 25 biologically active ligands with potent anti-hypertensive activities and performed molecular docking studies with the human ACE receptor (PDB ID 1O8A) and human leukocyte antigens (HLA) complex, human voltage-dependent calcium channel alpha1 subunit (PDB ID 3LV3). Beforehand, we had performed density functional theory (DFT) studies to find out their structure-property relationships.

Understanding asymmetric hydrogenation of alkenes catalyzed by the first-row transition metal Fe: a first-principles exploration.

First-principles analyses were performed for understanding the mechanistic details of Fe-catalysed asymmetric hydrogenation of alkenes in the presence of silane that has recently been experimentally realized. The catalytic hydrogenation is expected to proceed through initial hydride transfer from Fe-H to the CC bond of alkene, followed by σ-bond metathesis of hydrosilane to afford a chiral alkane product and an iron silyl species, which then reacts with H to regenerate the iron hydride species another σ-bond metathesis. The mechanistic details and the origin of the regioselectivity and stereoselectivity of these reactions are understood on the basis of detailed potential energy surface analysis, charge transfer and noncovalent interactions involved therein, strain energy and isodesmic studies in the solvated stage.

Photoinduced Regioselective Decarbonylative and Decarboxylative C-O Bond Functionalizations: Approach toward Chemoselective Scissions of Isatoic Anhydride and Unraveling the Enroutes through Control Experiments and DFT Studies.

Distinctive, green, innovative, and well-organized photoinduced (metal- or photocatalyst-free) regioselective decarbonylative and decarboxylative C-O bond functionalization protocols to access aryl 2-aminobenzoates and 2-substituted benzoxazinone derivatives in excellent yields have been devised. These are achieved through the chemoselective scission of isatoic anhydride with ketones, diaryliodonium triflate, nitroalkene, phthalazinone, and phenol derivatives, which, in turn, served as the representative "electrophilic and nucleophilic" coupling partners. Control experiments and DFT calculations reveal that electrophilic radical-bearing coupling partners specifically follow the decarbonylation pathway, while nucleophilic radical-bearing conjugates facilitate the decarboxylation process.

An insight into the role of ESIPT/TICT-based antioxidant flavone analogues in fluoro-probing diabetes-induced viscosity changes: a unified experimental and theoretical endeavour.

Potent antioxidants, like 3-hydroxy flavones, attracted considerable attention due to their excited state intramolecular proton transfer (ESIPT)-based fluorescence behaviour. This article is an interesting demonstration of a series of synthetic 3-hydroxy flavone analogues having high antioxidant activity as molecular rotor-like viscosity probes. Among these flavone analogues, 4'-N,N-dimethylamino-3-hydroxy flavone (3) is the most potent one, showing the twisted intramolecular charge transfer (TICT)-dependent fluoroprobing activity toward the blood viscosity changes associated with diabetes and free fatty acids (FFA)-induced nuclear viscosity changes of MIN6 cells.

Emergence of Z-Scheme Photocatalysis for Total Water Splitting: An Improvised Route to High Efficiency.

Photocatalytic water splitting to spontaneously produce H and O is a long-standing goal in solar energy conversion, presenting a significant challenge without using sacrificial electron donors or external biases. Inspired by natural photosynthesis, the design of artificial Z-scheme photocatalytic systems is at the forefront of this field. These systems achieve higher redox potential by separating photogenerated electrons and holes through a fast interlayer recombination process between valence and conduction band edges.

Dual-Channel Imine-Amine Photoisomerization in a Benzoimidazole and Benzothiazole Coupled System: Photophysics and Applications.

A molecule, namely 2-(1-benzo[]imidazol-2-yl)-6-(benzo[]thiazol-2-yl)-4-bromophenol (), having a two-way proton transfer unit of thiazole and imidazole moieties was synthesized and characterized by NMR, electrospray ionization mass spectrometry (ESI-MS), and single-crystal diffraction studies. Steady state and time-resolved spectral studies of support excited state intramolecular proton transfer (ESIPT), causing imine-amine tautomerization through a two-way 6-membered H-bonded ring, where the N atoms of benzothiazole and the benzoimidazole unit are involved as proton acceptor sites. Interestingly, in a nonpolar and moderately polar solvent, photoisomerization in is found to be favored toward the thiazole ring, whereas in a highly polar solvent, it is favored toward the imidazole ring.

Unravelling the Metal Sensing Activity of a Biologically Relevant Fluorescent Crown Ether: A Unified Experimental and Theoretical Study.

1,4-dihydropyridines (DHPs) are biologically active. 1,4-DHP analogs with appropriate substituents also show characteristic fluorescence activity. Here, for the first time, we report a simple and easy synthesis of a novel fluorescent 1,4- DHP derivative of dibenzo[18]-crown-6 (2), which showed promising sensing ability towards physiologically important metal ions.

Dual role far red fluorescent molecular rotor for decoding the plasma membrane and mitochondrial viscosity.

The dysfunctions in the mitochondria are associated with various pathological conditions like neurodegeneration, metabolic disorder, and cancer, leading to dysregulated cell death. Here, we have designed and synthesized a julolidine-based molecular rotor (JMT) to target mitochondria with far-red emission accounting for mitochondrial dysfunction. JMT showed viscosity sensitivity with 160-fold enhancement in fluorescence intensity.

Single B-vacancy enriched α-borophene sheet: an efficient metal-free electrocatalyst for CO reduction.

By employing first principles calculations, we have studied the electronic structures of pristine (α) and different defective (α, α) borophene sheets to understand the efficacy of such systems as metal-free electrocatalysts for the CO reduction reaction. Among the three studied systems, only α, the defective borophene sheet created by removal of a 5-coordinated boron atom, can chemisorb and activate a CO molecule for its subsequent reduction processes, leading to different C chemicals, followed by selective conversion into C products by multiple proton coupled electron transfer steps. The computed onset potentials for the C chemicals such as CHOH and CH are low enough.

Trivalent metal ion sensor enabled bioimaging and quantification of vaccine-deposited Al in lysosomes.

Extracellular metallic debris is deposited into the well-known 'recycle bins' of the cells named lysosomes. The accumulation of unwanted metal ions can cause dysfunction of hydrolyzing enzymes and membrane rupturing. Thus, herein, we synthesized rhodamine-acetophenone/benzaldehyde derivatives for the detection of trivalent metal ions in aqueous media.

Multi-action of a Fluorophore in the Sight of Light: Release of NO, Emergence of FONs, and Organelle Switching.

Light, as an external stimulus, has begun to engage a phenomenal role in the diverse field of science. Encouraged by recent progress from biology to materials chemistry, various light-responsive fluorescent probes have been developed. Herein, we present a 1,8-naphthalimide-based probe capable of releasing nitric oxide (NO) along with the formation of fluorescent organic nanoparticles (FONs) upon exposure to near-visible UV light.

Polaron Induced Conductance Switching in Conjugated Oligophenylene: A First-Principles Analysis.

For π-conjugated systems, polaron formation has a major impact on their optoelectronic properties. In fact, for such systems, an exquisite interplay between electron delocalization and the steric effect determines their ground state properties. However, an excess charge (positive or negative) injection causes structural reorientation because of extended conjugation.

Dual-Silicon-Doped Graphitic Carbon Nitride Sheet: An Efficient Metal-Free Electrocatalyst for Urea Synthesis.

Searching for an alternative nonhazardous catalyst for direct urea synthesis that avoids the traditional route of NH synthesis followed by CO addition is a challenging field of research nowadays. Based on first-principles calculations, we herein propose a novel electrocatalyst comprising of totally nonmetal earth abundant elements (dual-Si doped g-CN sheet) which is capable of activating N and making it susceptible toward direct insertion of CO into the N-N bond, producing *NCON* which is the precursor for urea production by direct coupling of N and CO followed by multiple proton coupled electron transfer processes. Remarkably, the calculated onset potential for urea production is much less than that of NH synthesis and hydrogen evolution reactions, and also the faradaic efficiency is nearly 100% for production urea over ammonia, which promotes exclusive electrocatalytic urea synthesis by suppressing the NH synthesis as well as hydrogen evolution reactions.

Exploring the Propensities of Fluorescent Carbazole Analogs toward the Inhibition of Amyloid Aggregation in Type 2 Diabetes: An Experimental and Theoretical Endeavor.

Amyloid aggregation is a pathological trait observed in many incurable and fatal neurodegenerative and metabolic diseases associated with misfolding and self-assembly of various proteins. Noncovalent interactions between these structural motifs and small molecules can, however, prevent this aggregation. Herein, five structurally different synthetic (Cz1-Cz4) and naturally occurring (Cz5, mahanimbine) fluorescent carbazole analogs are explored for their comparative amyloid aggregation inhibitory activities.

Graphitic Carbon Nitride Sheet Supported Single-Atom Metal-Free Photocatalyst for Oxygen Reduction Reaction: A First-Principles Analysis.

Designing metal-free photocatalysts for oxygen reduction reaction (ORR) is an important step toward the development of sustainable and alternative energy resources because ORR plays a key role in fuel cell reactions. An efficient photocatalyst for ORR must possess suitable band positions with respect to electrochemical potentials of ORR, minimize energy losses due to charge transport and electron-hole recombination, and have kinetically suitable electron transfer properties. Using first-principles theoretical studies, we herein demonstrate that a single Si atom doped on the alternative pores of the porous graphitic carbon nitride (g-CN) surface has satisfied the above criteria and has the potential to be an efficient photocatalyst for ORR.

Towards HO catalyzed N-fixation over TiO doped Ru clusters ( = 5, 6): a mechanistic and kinetic approach.

H2O driven N2 fixation is known as the best alternative pathway to synthesise NH3 under ambient conditions. The thermodynamic non-spontaneous reaction can be accomplished by a photocatalytic water splitting reaction over a TiO2 supported surface with oxygen vacancies. Previous experiments have also shown N2 activation over a neutral Ru cluster whose catalytic activity was remarkably enhanced by TiO2 doping.

Unfolding the Role of a Flavone-Based Fluorescent Antioxidant towards the Misfolding of Amyloid Proteins: An Endeavour to Probe Amyloid Aggregation.

4'-,-Dimethylamino-3-hydroxyflavone (DMAHF), a synthetic fluorescent flavone analogue with potent antioxidant activity, was explored as a molecular rotor-like fluoroprobe for amyloid aggregations, a causative factor in Alzheimer's disease, Parkinson's disease, type-2 diabetes, etc. During its interactions with (human) insulin amyloid aggregation (IAA), its microenvironment was changed. This instigated a drastic change in its excited-state intramolecular proton transfer-based dual emission behavior, which was tracked to monitor its amyloid probing activity.

Theoretical Investigations on the Possibility of Prebiotic HCN Formation via O-Addition Reactions.

Until now, reactions between methane photolysis products (CH, CH) and active N atom or reactive NO radical are proposed as routes of HCN formation in the prebiotic Earth. Scientists think that the reducing atmosphere of primitive Earth was made of H, He, N, NO, CH, HO, CO, etc., and there was no molecular oxygen.

Structural rigidity accelerates quantum decoherence and extends carrier lifetime in porphyrin nanoballs: a time domain atomistic simulation.

Nonradiative electron-hole (e-h) recombination is the primary source of energy loss in photovoltaic cells and inevitably, it competes with the charge transfer process, leading to poor device performance. Therefore, much attention has to be paid for delaying such processes; increasing the excitonic lifetime may be a solution for this. Using the real-time, density functional tight-binding theory (DFTB) combined with nonadiabatic molecular dynamics (NAMD) simulations, we demonstrate the exciton relaxation phenomena of different metal-centered porphyrin nanoballs, which are supposed to be very important for the light-harvesting process.

CHNO as a potential intermediate for early atmospheric HCN: a quantum chemical insight.

Hydrogen cyanide (HCN) has played a central role in the production of several biological molecules under prebiotic conditions on primitive Earth. Previously, K. J.

Mechanistic insights into the non-bifunctional hydrogenation of esters by Co(ii) pincer complexes: a DFT study.

A recent experiment has revealed that additive free ester hydrogenation by Co-pincer complexes might follow an unusual non-bifunctional mechanism, however, the detailed mechanistic pathway is missing. It has been predicted that several intermediates and transition states are involved, having their essential role in the catalytic performances. Detailed theoretical studies are therefore essential in this regard for achieving more efficient ester hydrogenation catalysts.

Unambiguous hydrogenation of CO by coinage-metal hydride anions: an intuitive idea based on in silico experiments.

Gas phase hydrogenation of CO2 to HCO2- by coinage-metal hydride anions, MH- (M = Cu, Ag and Au), has been studied with the help of high level computational methodologies. We demonstrate that these hydride anions perform excellently in the specific hydrogenation of CO2 to HCO2-. More precisely, AgH- is shown to be very active for this particular purpose.

Harnessing carbazole based small molecules for the synthesis of the fluorescent gold nanoparticles: A unified experimental and theoretical approach to understand the mechanism of synthesis.

Six structurally different carbazoles (1-6) were explored as the green reducing agents for the synthesis of the fluorescent Au nanoparticles with tailor-made morphology in anionic (sodium dodecyl sulphate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and neutral (polyvinylpyrrolidone, PVP) micelle medium. Structure of the carbazoles played an important role in controlling the morphology, rate of formation and fluorescent activity of the Au nanoparticles. The Au nanoparticles formed in-situ also simultaneously catalyzed the intermolecular CC and NN couplings between the carbazoles, leading to the corresponding bis-carbazole derivatives.

Essential Role of Ancillary Ligand in Color Tuning and Quantum Efficiency of Ir(III) Complexes with N-Heterocyclic or Mesoionic Carbene Ligand: A Comparative Quantum Chemical Study.

Tuning photoluminescence properties is of prime importance for designing efficient light emitting diode (LED) materials. Here, we perform a computational study on the effect of normal N-heterocyclic carbene (NHC) and abnormal mesoionic carbene (MIC) ligands on the photoluminescence properties of some Ir(III) complexes, which are very promising LED materials. We find MIC as the privileged ligand in designing triplet emitters.