An analysis of structural phase transition and allied properties of cubic ReN and MoN compounds

Sequence-Prescribed β-Sheet for Enhanced Electron Tunneling: Boosting Interface Recognition and Electrochemical Measurement

Peptide self-assemblies could leverage their specificity, stability, biocompatibility, and electrochemical activity to create functionalized interfaces for molecular sensing and detection. However, the dynamics within these interfaces are complex, with competing forces, including those maintaining peptide structures, recognizing analytes, and facilitating signal transmission. Such competition could lead to nonspecific interference, compromising the detection sensitivity and accuracy. In this study, a series of peptides with precise structures and controllable electron transfer capabilities were designed. Through examining their stacking patterns, the interplay between the peptides' hierarchical structures, their ability to recognize targets, and their conductivity were clarified. Among these, the EP5 peptide assembly was identified for its ability to form controllable electronic tunnels facilitated by π-stacking induced β-sheets. EP5 could enhance the long-range conductivity, minimize nonspecific interference, and exhibit targeted recognition capabilities. Based on EP5, an electrochemical sensing interface toward the disease marker PD-L1 (programmed cell death ligand 1) was developed, suitable for both whole blood assay and in vivo companion diagnosis. It opens a new avenue for crafting electrochemical detection interfaces with specificity, sensitivity, and compatibility.

Investigating the potential of monocyclic B9N9 and C18 rings for the electrochemical sensing, and adsorption of carbazole-based anti-cancer drug derivatives: DFT-based first-principle study

CONTEXT

For the first time, the use of monocyclic rings C18 and B9N9 as sensors for the sensing of carbazole-based anti-cancer drugs, such as tetrahydrocarbazole (THC), mukonal (MKN), murrayanine (MRY), and ellipticine (EPT), is described using DFT simulations and computational characterization. The geometries, electronic properties, stability studies, sensitivity, and adsorption capabilities of C18 and B9N9 counterparts towards the selected compounds confirm that the analytes interact through active cavities of the C18 and B9N9 rings of the complexes.

METHODS

Based on the interaction energies, the sensitivity of surfaces towards EPT, MKN, MRY, and THC analytes is observed. The interaction energy of EPT@B9N9, MKN@B9N9, MRY@B9N9, and THC@B9N9 complexes are observed - 20.40, - 19.49, - 20.07, and - 18.27 kcal/mol respectively which is more exothermic than EPT@C18, MKN@C18, MRY@C18, and THC@C18 complexes are - 16.37, - 13.97, - 13.96, and - 11.39 kcal/mol respectively. According to findings from the quantum theory of atoms in molecules (QTAIM) and the reduced density gradient (RDG), dispersion forces play a significant role in maintaining the stability of these complexes. The electronic properties including FMOs, density of states (DOS), natural bond orbitals (NBO), charge transfer, and absorption studies are carried out. In comparison of B9N9 and C18, the analyte recovery time for C18 is much shorter (9.91 × 10-11 for THC@C18) than that for B9N9 shorter recovery time value of 3.75 × 10-9 for EPT@B9N9. These results suggest that our reported sensors B9N9 and C18 make it faster to detect adsorbed molecules at room temperature. The sensor response is more prominent in B9N9 due to its fine energy gap and high adsorption energy. Consequently, it is possible to think of these monocyclic systems as a potential material for sensor applications.

Drug repositioning identifies salvinorin A and deacetylgedunin (DCG) enriched plant extracts as novel inhibitors of Mpro, RBD-ACE2 and TMPRRS2 proteins

The coronavirus disease 2019 (COVID-19) has spread worldwide with severe health, social, and economic repercussions. Although vaccines have significantly reduced the severity of symptoms and deaths, alternative medications derived from natural products (NPs) are vital to further decrease fatalities, especially in regions with low vaccine uptake. When paired with the latest computational developments, NPs, which have been used to cure illnesses and infections for thousands of years, constitute a renewed resource for drug discovery. In the present report, a combination of computational and in vitro methods reveals the repositioning of NPs and identifies salvinorin A and deacetylgedunin (DCG) as having potential anti-SARS-CoV-2 activities. Salvinorin A was found both in silico and in vitro to inhibit both SARS-CoV-2 spike/host ACE2 protein interactions, consistent with blocking viral cell entry, and well as live virus replication. Plant extracts from Azadirachta indica and Cedrela odorata, which contain high levels of DCG, inhibited viral cell replication by targeting the main protease (Mpro) and/or inhibited viral cell entry by blocking the interaction between spike RBD-ACE2 protein at concentrations lower than salvinorin A. Our findings suggest that salvinorin A represent promising chemical starting points where further optimization may result in effective natural product-derived and potent anti-SARS-CoV-2 inhibitors to supplement vaccine efforts.

Narrowband emission from fully-bridged triphenylamine derivatives: insights into effects of structure modification and pressure

Triphenylamine derivatives with narrowband emission have attracted growing attention in purely organic thermally-activated fluorescence (TADF) materials owing to their enhanced color purity and flexible molecular design strategy. Combined time-dependent density functional theory (TD-DFT) and ONIOM (QM/MM) calculations indicate that the excellent planarity of the experimentally developed DQAO could result in gradually decreased intermolecular interactions in the aggregated state at ambient pressure and upon compression, which is unfavorable for suppressing structural relaxation and achieving narrowband emission in its non-doped practical application. Therefore, three structure-modified derivatives, DQAO-Cb, DQAO-Ph, and DQAO-PhCb, were theoretically designed by introducing the spherical o-carborane and dangling phenyl units positioned para to the N atom of the DQAO to provide additional geometrical distortion and steric hindrance. The explorations on the reported DQAO, OQAO, and SQAO found that small structural relaxations, suppressed low-frequency vibrations, and noticeable short-range charge-transfer (SR-CT) natures of DQAO and OQAO are responsible for their much narrower emission spectral full-width at half-maxima (FWHMs) compared to that of SQAO. Introducing the o-carborane unit directly at the para position of the N atom could result in additional scissoring and stretching vibrations of the corresponding DQAO-Cb while the presence of the phenyl unit in DQAO-Ph is beneficial for suppressing the high-frequency vibrations of the pristine DQAO. More importantly, the bridged phenyl unit incorporated in DQAO-PhCb is of particular importance to inhibit the undesired low-frequency scissoring and high-frequency stretching vibrations of the o-carborane unit, which is crucial to reduce the reorganization energy of DQAO-PhCb and achieve narrowband emission. Also, the phenyl unit in DQAO-Ph and DQAO-PhCb helps to shorten charge transfer distances and improve ISC and RISC processes. Since the o-carborane unit is an adopted building block to achieve piezochromic behaviors, the theoretically structure-modified DQAO-PhCb is expected to exhibit narrowband emission, TADF, and piezochromic features all together. Our findings will hopefully provide ideas for designing triphenylamine-based TADF emitters with narrowband emission and piezochromic behaviors.

Narrowband TADF emitters with high utilization of triplet excitons: theoretical insights and molecular design

Narrowband emitters with thermally activated delayed fluorescence (TADF) features, known as multi-resonant TADF (MR-TADF) emitters, are drawing increasing research interest owing to their properties of high efficiency and excellent color purity. However, MR-TADF-based devices often face serious efficiency roll-off at high luminance intensity, which could be attributed to undesired triplet-triplet annihilation (TTA) caused by the structural planarity and relatively small reverse intersystem crossing rate constants (krisc) of MR-TADF emitters. Herein, combining a sp3-C inserted strategy to suppress harmful bimolecular interactions and chalcogens to improve the krisc, a series of asymmetric narrowband emitters, namely, DMAC-O, DMAC-S, and DMAC-Se, have been theoretically designed to break the slow rate-limiting step of krisc of experimental BN-DMAC. For comparison, both O and Se atoms were doped into the MR skeleton to substitute two sp3-inserted units, yielding BN-O-Se. The combination of TD-DFT and the wavefunction-based STEOM-DLPNO-CCSD approach exhibits that those asymmetric molecules are promising for simultaneously exhibiting narrow emission spectral full-width at half-maximums (FWHMs) and high luminous efficiencies. The contributions of chalcogens to hole distributions result in red-shifted fluorescent peaks, and the asymmetric strategy also helps with twisted molecular configuration, which is beneficial for suppressing unfavorable TTA. Furthermore, the incorporation of chalcogens is sufficient to promote the intersystem crossing and reverse intersystem crossing channels of asymmetric emitters. More importantly, the doped heavy Se atom results in a significantly increased krisc of 2.32 × 106 s-1 for DMAC-Se, which is more than 200 times larger than 1.09 × 104 s-1 of pristine BN-DMAC. These results suggest that the combination of the heavy Se atom and an sp3-inserted unit is a feasible strategy for achieving poor planarity and significantly enhancing krisc, which will help in harvesting triplet excitons, thereby inhibiting efficiency roll-off in corresponding narrowband devices.

Bifunctional diatomic site catalysts supported by β12-borophene for efficient oxygen evolution and reduction reactions

Efficient bifunctional catalysts for oxygen evolution and reduction reactions (OERs/ORRs) are of great importance for sustainable and renewable clean energy, especially for metal-air batteries. Herein, we investigated β12-borophene with double-hole sites capped with 3d transition metal atoms to explore its catalyst performance for hydrogen evolution reactions (HERs), OERs and ORRs. It was found that the borophene is a good platform for diatomic site catalysts (DASCs) due to their advantage of stability over the corresponding single-atom catalysts (SACs) or clusters. The HER performance of DASCs on β12-BM was further improved compared to the SAC case. Furthermore, the supported FeNi DASC exhibited good catalytic performance for both OERs and ORRs, the overpotentials for which were 0.43 and 0.55 V, respectively, better than those of the corresponding supported Ni or Fe SAC due to synergistic effects. We herein propose a novel descriptor involving the Bader charges of coordinated atoms explicitly, behaving much better than the d-band center and integrated crystal orbital Hamilton population (-ICOHP) for DASCs. The synergistic effect of Fe-Ni pairs balanced the too strong binding of OH and further activated OH to achieve better catalytic performance. The results of this study can provide theoretical guidance for the design of efficient bifunctional electrocatalysts.

Propranolol induces large-scale remodeling of lipid bilayers: tubules, patches, and holes

Herein, we report fluorescence microscopy analysis of the interaction between propranolol (PPN), a beta-adrenergic blocking agent, and planar supported lipid bilayers (SLBs), as model membranes. The results indicate that PPN can remarkably promote largescale remodeling in SLBs with various lipid compositions. It was found that PPN insertion induces the formation of long microtubules that can retract into hemispherical caps on the surface of the bilayer. These transformations are dynamic, partially reversible, and dependent upon the drug concentration. Quantitative analysis revealed a three-step model for PPN-lipid bilayer interaction, with the first step involving interfacial electrostatic adsorption, the second step centered on hydrophobic insertion, and the third step associated with membrane disruption and hole formation. By introducing cholesterol, phosphoethanolamine, phosphatidylglycerol, and phosphatidylserine lipids into the phosphocholine SLBs, it was illustrated that both the chemistry of the lipid headgroups and the packing of lipid acyl chains can substantially affect the particular steps in the interactions between PPN and lipid bilayers. Our findings may help to elucidate the possible mechanisms of PPN interaction with lipid membranes, the toxic behavior and overdosage scenarios of beta-blockers, and provide valuable information for drug development and modification.

Alteration of the central core of a DF-PCIC chromophore to boost the photovoltaic applications of non-fullerene acceptor based organic solar cells

Modifying the central core is a very efficient strategy to boost the performance of non-fullerene acceptors. Herein five non-fullerene acceptors (M1-M5) of A-D-D'-D-A type were designed by substituting the central acceptor core of the reference (A-D-A'-D-A type) with different strongly conjugated and electron donating cores (D') to enhance the photovoltaic attributes of OSCs. All the newly designed molecules were analyzed through quantum mechanical simulations to compute their optoelectronic, geometrical, and photovoltaic parameters and compare them to the reference. Theoretical simulations of all the structures were carried out through different functionals with a carefully selected 6-31G(d,p) basis set. Absorption spectra, charge mobility, dynamics of excitons, distribution pattern of electron density, reorganization energies, transition density matrices, natural transition orbitals and frontier molecular orbitals, respectively of the studied molecules were evaluated at this functional. Among the designed structures in various functionals, M5 showed the most improved optoelectronic properties, such as the lowest band gap (2.18 e V), highest maximum absorption (720 nm), and lowest binding energy (0.46 eV) in chloroform solvent. Although the highest photovoltaic aptitude as acceptors at the interface was perceived to be of M1, its highest band gap and lowest absorption maxima lowered its candidature as the best molecule. Thus, M5 with its lowest electron reorganization energy, highest light harvesting efficiency, and promising open-circuit voltage (better than the reference), amongst other favorable features, outperformed the others. Conclusively, each evaluated property commends the aptness of designed structures to augment the power conversion efficiency (PCE) in the field of optoelectronics in one way or another, which reveals that a central un-fused core having an electron-donating capability with terminal groups being significantly electron withdrawing, is an effective configuration for the attainment of promising optoelectronic parameters, and thus the proposed molecules could be utilized in future NFAs.

Designing dibenzosilole core based, A2-π-A1-π-D-π-A1-π-A2 type donor molecules for promising photovoltaic parameters in organic photovoltaic cells

In this research work, four new molecules from the π-A-π-D-π-A-π type reference molecule "DBS-2PP", were designed for their potential application in organic solar cells by adding peripheral A2 acceptors to the reference. Under density functional theory, a comprehensive theoretical investigation was conducted to examine the structural geometries, along with the optical and photovoltaic parameters; comprising frontier molecular orbitals, density of states, light-harvesting effectiveness, excitation, binding, and reorganizational energies, molar absorption coefficient, dipole moment, as well as transition density matrix of all the molecules under study. In addition, some photo-voltaic characteristics (open circuit photo-voltage and fill factor) were also studied for these molecules. Although all the developed compounds (D1-D4) surpassed the reference molecule in the attributes mentioned above, D4 proved to be the best. D4 possessed the narrowest band-gap, as well as the highest absorption maxima and dipole moment of all the molecules in both the evaluated phases. Moreover, with PC61BM as the acceptor, D4 showed the maximum V OC and FF values. Furthermore, while D3 had the greatest hole mobility owing to its lowest value of hole reorganization energy, D4 exhibited the maximum electron mobility due to its lowermost value of electron reorganization energy. Overall, all the chromophores proposed in this study showed outstanding structural, optical, and photovoltaic features. Considering this, organic solar cell fabrication can be improved by using these newly derived donors at the donor-acceptor interfaces.

Adsorption, thermodynamic, and quantum chemical investigations of an ionic liquid that inhibits corrosion of carbon steel in chloride solutions

The purpose of this work lies in the use of ionic liquids as corrosion inhibitors due to the difficulty in some oil fields with the solubility of corrosion inhibitors and these materials can be miscible with water and thus provide a solution to such problems in the industry. The second purpose is concerned with the lower toxicity of these compounds compared with the most common corrosion inhibitors. The study covered the corrosion inhibition performance of the ionic liquid 1-butyl-3-methylimidazolium trifluoromethyl sulfonate ([BMIm]TfO) for carbon steel in 3.5% NaCl solutions. The study comprised electrochemical, adsorption, and quantum chemical investigations. The results manifested that [BMIm]TfO can be considered a promising corrosion inhibitor and the inhibition efficacy intensifies as the concentration rises. The observed inhibitive effect can be correlated to the adsorption of the ionic liquid species and the creation of protecting films on the surface. The mode of adsorption follows the Langmuir adsorption isotherm. The polarization results showed that the ionic liquid [BMIm]TfO functions as a mixed inhibitor. Reliance of the corrosion influence on the temperature in the existence and absence of [BMIm]TfO was demonstrated in the temperature range of 303-333 K using polarization data. Activation parameters were determined and discussed. The observed inhibition performance of [BMIm]TfO was correlated with the electronic properties of the ionic liquid using a quantum chemical study.

Ab initio molecular dynamics simulations on the adsorption of 1-hydroxyethane-1,1-diphosphonic acid on the iron (100) surface

Through IRI, Bader charges and ELF analysis, an electrostatic interaction network exists between HEDP and the iron (100) surface, which is responsible for the stability of the adsorption state.

Elucidating the selectivity of dyotropic rearrangements of β-lactones: a computational survey

A comprehensive computational study on dyotropic rearrangements of β-lactones has been performed for the first time, which provides a valuable guidance for predicting and controlling the selectivity of the reactions.

Introduction of the acylamino group to bridged bis(nitroamino-1,2,4-triazole): a strategy for tuning the sensitivity of energetic materials

Introduction of the acylamino group into energetic material compounds will contribute to balancing the sensitivity and the energy.