Photodynamics simulation insights into excited-state relaxation mechanisms via Z/E isomerization in para-amino substituted GFP chromophores.

The ability of green fluorescent protein (GFP) chromophore and its derivatives to undergo cis-trans photoswitching behavior has been widely acknowledged as of great interest because of its emerging applications in optogenetics and optoelectronics. However, key aspects of the internal conversion process in the GFP chromophore derivatives remain largely unclear. Based on quantum chemical methods and on-the-fly nonadiabatic dynamics simulations, we investigated the ultrafast photoinduced cis-trans isomerization phenomenon in the para-amino (NH2-HBDI) derivative of the GFP chromophore, which is intrinsically non-fluorescent.

Study of Electron Capture by 5-Halogenated Cytosine in Gas and Condensed Phases.

Halogenated pyrimidines have been a compound of interest for a long time due to their wide range of applications in biological science. In this study, we sought to evaluate the effectiveness of halogenated cytosine as a radiosensitizer by analyzing its interaction with low-energy electrons produced during radiotherapy. Our results revealed that halogenated cytosine forms a dipole-bound state in the gas phase after electron attachment in the Franck-Condon region.

BF·OEt-Mediated Cascade Synthesis of 4-3,1-Benzoxazines from 2-Azidobenzaldehydes and Homoallylic Alcohols.

Herein, we developed a methodology for the synthesis of 4-3,1-benzoxazine derivatives by utilizing 2-azidobenzaldehydes and homoallylic alcohols in the presence of BFOEt in moderate to good yields. This reaction proceeds via retro-Prins reaction, followed by nucleophilic attack by azide and subsequent elimination of nitrogen and proton. In addition, the method was successfully applied for the synthesis of triazole compounds via the click reaction.

Deciphering the Underlying Mechanism of Anion Binding by Asymmetrical Squaramide-Based Dipeptides.

Anions are involved in many important processes, which has led to growing interest in designing new molecules to bind them effectively. Squaramides have gained considerable attention as effective anion receptors due to their dual hydrogen bond donor capability. Combining squaramide with biomolecules is a promising approach for designing and developing biomimetic receptors for anions with enhanced H-bonding abilities, particularly due to their functional versatility.

Unveiling the Atmospheric Oxidation of Hexafluoroisobutylene, (CF)C═CH, with Cl Atom, NO Radical, and O Molecule.

The CFC alternative, 3,3,3-trifluoro-2(trifluoromethyl)-1-propene, (CF)C═CH (HFIB), plays a pivotal role across various industrial sectors owing to its unique chemical properties, versatility, and diverse applications as a refrigerant, propellant, aerosol, etc. However, its extensive presence in industrial processes raises concerns about its environmental impact. In this study, atmospheric oxidation of HFIB by reaction with Cl, NO, and O is investigated theoretically to unravel the reaction mechanism, thermodynamics, and kinetics.

Unprecedented binding of Thioflavin T with well-ordered spherical aggregates: A false positive?

Amyloidogenic protein aggregation is a hallmark of numerous neurodegenerative diseases, including Alzheimer's and Parkinson's diseases. Thioflavin T (ThT), which selectively interacts with fibrillar amyloid structures, holds significant promise for diagnostic and therapeutic applications. Herein, we investigate the binding behaviour of Thioflavin T (ThT), a widely employed amyloid-specific fluorophore, with well-ordered spherical aggregates formed by dipeptides Boc-Phe-Trp-OMe (FW), Boc-Val-Trp-OMe (VW), Boc-Leu-Trp-OMe (LW) and Boc-Ile-Trp-OMe (IW).

An electrically conductive dinuclear aluminium complex for the fabrication of a Schottky diode.

Electrical performances of a biphenyl-derived amido Schiff base ligand L and its dinuclear Al(iii) complex (complex 1) were investigated in a metal-semiconductor (MS) junction. Electrical studies revealed that complex 1 significantly enhanced the electrical conductivity and improved the characteristics of a Schottky barrier diode (SBD). The - characteristics demonstrated that complexation of ligand L with Al(iii) ion increased the conductivity by two orders of magnitude (conductivity of L = 1.

Bimetallic Cooperativity of a Ferrocene-Based Iridium NHC Complex in Water Oxidation Catalysis: A New Frontier for Efficient Oxygen Evolution.

Bimetallic catalysts have gained attention as promising contenders, owing to the synergistic interaction between two distinct metal centers. In this study, we present two N-heterocyclic carbene iridium(III) pentamethylcyclopentadienyl complexes [Cp*Ir(fcpyNHC)Cl]PF (1) and [Cp*Ir(pyNHC)Cl]PF (2) where 1 includes a ferrocene moiety making it a bimetallic complex. Using ceric ammonium nitrate as a sacrificial oxidant, both complexes were tested for water oxidation.

Role of Active Centers in Predicting the Catalyst Turnover: A Theoretical Study.

Water oxidation catalysis has garnered significant attention due to its potential for sustainable energy conversion. Among molecular catalysts, [Fe(OTf)( Pytacn)] complexes have exhibited notable turning-over rates. Although various [M(OTf)( Pytacn)] complexes (M=Mn, Co, Ni) have been synthesized, however, the role of active centres has not been thoroughly investigated.

Mechanistic insights into the electron attachment process to guanosine in the presence of arginine.

The attachment of low-energy electrons (LEEs) to DNA biomolecules leads to irreversible damage. However, the behavior of this interaction can be influenced by the presence of amino acids. Herein, we have delved into the mechanism of electron attachment to the guanosine in the presence of arginine.

End Group Effects on Anion Binding in Tetraglycine Peptide: A Computational Study.

The importance of anions in various processes has led to a search for molecules that can effectively recognize and interact with these anions. This study explores how the tetraglycine [(Gly)] peptide in its zwitterionic, neutral, and terminally capped forms acts as a receptor for HPO and HSO anions within the framework of supramolecular host-guest chemistry. Using molecular dynamics (MD) simulations, we obtained the conformations of the receptor-anion complexes.

Dissociative electron attachment to halogenated nucleotides: a quest for better radiosensitizers.

Tumor hypoxia hampers radiotherapy efficacy, necessitating radiosensitizers. Substituted nucleobases offer advantages as radiosensitizers. They can be incorporated into DNA with minimal gene-expression alteration, selectively targeting tumor cells and having lower toxicity to normal tissues.

Unraveling the Stability and Magnetic Properties of Bis-Hydrated Mn(II) Complexes via Tailored Ligand Design.

Exploring the electronic structure and dynamic behavior of Mn(II) complexes reveals fascinating magnetic properties and prospective biomedical applications. In this study, we investigate the solvent phase dynamics of heptacoordinated Mn(II) complexes through ab initio molecular dynamics simulations and density functional theory (DFT) calculations with effectively varying temperatures. We observed that the complex with high stability ([Mn(pmpa)(HO)]) remains relatively rigid as the temperature increases to 90 °C, with only a minor change in its radial distribution functions (RDFs), compared to the RDF peaks at 25 °C.

MaxKinEff: A Collision Theory-Based Approach for Analyzing Turnover Frequency and Turnover Number in Catalytic Processes.

The efficiency of catalysts relies on comprehending the underlying kinetics that govern their performance. Under the steady-state regime, the "rate" is referred to as the turnover frequency, where the reaction rate is first order with respect to catalysts. Here, we introduce the Maximum Kinetic Efficiency (MaxKinEff) model, grounded in collision theory, to predict efficiency based on maximum turnover frequency, and maximum turnover number, .

Investigating the Atmospheric Fate and Kinetics of OH Radical-Initiated Oxidation Reactions for Epoxybutane Isomers: Theoretical Insight.

Epoxides, which belong to the category of oxygenated volatile organic compounds (OVOCs), are emitted into the atmosphere by an array of sources and can impact both human and environmental well-being significantly. This study involves comprehensive computational analyses aimed at investigating the mechanism, thermodynamic aspects, and reaction kinetics associated with hydrogen abstraction reactions of -2,3-epoxybutane, -2,3-epoxybutane, and 1,2-epoxybutane by OH radicals. The potential energy diagrams involving all of the species for each specific pathway were constructed at the CCSD(T)/aug-cc-pVTZ//M06-2X/cc-pVTZ level of theory.

Ultrafast Hot Exciton Nonadiabatic Excited-State Dynamics in Green Fluorescent Protein Chromophore Analogue.

The ultrafast high-energy nonadiabatic excited-state dynamics of the benzylidenedimethylimidazolinone chromophore dimer has been investigated using an electronic structure method coupled with on-the-fly quantitative wave function analysis to gain insight into the photophysics of hot excitons in biological systems. The dynamical simulation provides a rationalization of the behavior of the exciton in a dimer after the photoabsorption of light to higher-energy states. The results suggest that hot exciton localization within the manifold of excited states is caused by the hindrance of torsional rotation due to imidazolinone (I) or phenolate (P) bonds i.

Regioselective and solvent-dependent photoisomerization induced internal conversion in red fluorescent protein chromophore analogues.

Photophysical properties of three red fluorescent protein (RFP) chromophore analogues are reported here. The three RFP chromophore analogues differ in the additional conjugation present in the RFP chromophore. The three chromophores do not exhibit any solvent effect in both absorption and fluorescence spectra.

Revisiting fulgide photochromism: Mechanistic decoding and electron transport from computational exploration.

The photochromic behavior of the fulgide molecule relies on ring-closure and ring-opening processes involving conical intersections during excited state transformation between isomers. The precise location and topography of these conical intersections significantly shape the decay process and fluorescence phenomena inherent to the molecule. This work combines electronic structure theory calculations using the density functional theory and wavefunction methods, as well as surface hopping simulation to analyze the photochemical behavior of an experimentally synthesized fulgide molecule, (E)-p-methylacetophenylisopropylidenesuccinic anhydride (1E).

Realization of efficient and selective NO and NO detection surface functionalized h-BS monolayer.

In the ever-growing field of two-dimensional (2D) materials, the boron-sulfide (BS) monolayer is a promising new addition to MoS-like 2D materials, with the boron (a lighter element) pair (B pair) having similar valence electrons to Mo. Herein, we have functionalized the h-phase boron sulfide monolayer by introducing oxygen atoms (Oh-BS) to widen its application scope as a gas sensor. The charge carrier mobilities of this system were found to be 790 × 10 cm V s and 32 × 10 cm V s for electrons and holes, respectively, which are much higher than the mobilities of the MoS monolayer.

Efficiency Conceptualization Model: A Theoretical Method for Predicting the Turnover of Catalysts.

In recent times, the theoretical prediction of catalytic efficiency is of utmost urgency. With the advent of density functional theory (DFT), reliable computations can delineate a quantitative aspect of the study. To this state-of-the-art approach, valuable incorporation would be a tool that can acknowledge the efficiency of a catalyst.

Deciphering the Internal Conversion Processes Involved in the Photochemical Ring-Opening of 1,3-Cyclohexadiene by Symmetric sp-Carbon Substitutions.

Chemical substituents hold the potential to markedly influence the photochemical behavior in molecular systems and assist in gaining a comprehensive understanding of nonadiabatic phenomena. In this study, we have conducted a comparative analysis of the influence of chemical substituents on the photochemical ring-opening of 1,3-cyclohexadiene (CHD), considering four systems: CHD, 2,3-dimethylcyclohexadiene (CHD-Me2-1), 1,4-dimethylcyclohexadiene (CHD-Me2-2), and 1,2,3,4-tetramethylcyclohexadiene (CHD-Me4), using electronic structure theory calculations and nonadiabatic molecular dynamics simulations. Employing extended multistate complete active space second-order perturbation (XMS-CASPT2) theory, we optimized reactants, S states, conical intersections (CIs), and products, revealing structural and energetic variations consistent with prior research.

Probing the dynamic behaviour and magnetic identification of seven coordinated Mn(II) complexes: a combined AIMD and multi-reference approach.

We present an in-depth solution phase dynamics of rare seven coordinated pentagonal bipyramidal Mn(II) complexes, together with their binding affinity anticipated using molecular dynamics (AIMD) simulations and density functional theory (DFT). Moreover, the simulations at different temperatures (25 °C and 90 °C) interpret the rigidity and stability of the ligands with Mn(II) ions. An intuitive approach for modulating the easy plane magnetic anisotropy of the mononuclear Mn(II) complex has been revealed by this work.

Exploring π-π interactions and electron transport in complexes involving a hexacationic host and PAH guest: a promising avenue for molecular devices.

Single isolated molecules and supramolecular host-guest systems, which consist of π-π stacking interactions, are emerging as promising building blocks for creating molecular electronic devices. In this article, we have investigated the noncovalent π-π interaction and intermolecular electron charge transport involved in a series of host-guest complexes formed between a cage-like host (H) and polycyclic aromatic hydrocarbon (PAH) guests (G1-G7) using different quantum chemical approaches. The host (H) consists of two triscationic π-electron-deficient trispyridiniumtriazine (TPZ) units that are bridged face-to-face by three ethylene-triazole-ethylene.

Unveiling the Noncovalent Interaction of Thiazol-2-ylidene and Its Derivatives as N-heterocyclic Carbene with Different Proton Donor Molecules.

The importance of noncovalent interaction has gained attention in various domains covering drug and novel catalyst design. The present study mainly characterizes the role of hydrogen bond (H-bond) and other intermolecular interactions in different (1 : 1) complex analogues formed between the N-aryl-thiazol-2-ylidene (YR) and five proton donor (HX) molecules. The analysis of the singlet-triplet energy gap ( ) confirmed the stability of the singlet state for this class of N-aryl-thiazol-2-ylidenes than the triplet state.