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1.
Phys Chem Chem Phys ; 26(14): 10557-10567, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38530661

RESUMO

Motivated by the report of the giant Rashba effect in ternary layered compounds BiTeX, we consider two Janus structured compounds Ti2N2XI (X = Br, Cl) of the same ternary family exhibiting a 1 : 1 : 1 stoichiometric ratio. Broken inversion symmetry in the Janus structure, together with its unique electronic structure exhibiting anti-crossing states formed between Ti-d states and strong spin-orbit coupled I-p states, generates large Rashba cofficients of 2-3 eV Å for these compounds, classifying them as strong Rashba compounds. The anti-crossing features of the first-principles calculated electronic structure also result in non-trivial topology, combining two quantum phenomena - Rashba effect and non-trivial topology - in the same materials. This makes Janus TiNI compounds candidate materials for two-dimensional composite quantum materials. The situation becomes further promising by the fact that the properties are found to exhibit extreme sensitivity and tunability upon application of uniaxial strain.

2.
Inorg Chem ; 62(51): 21353-21363, 2023 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-38059481

RESUMO

The effect of nonstoichiometry on the cation distribution, crystal structure, and magnetic properties of a series of Cr-rich Sr2Cr1+xRe1-xO6 samples has been investigated. The double perovskite structure is maintained over a wide solid solution range that extends from x = 0 to approximately x = 0.5. For most of the solid solution range, the Cr-rich octahedral site maintains a nearly constant occupancy, 87% Cr and 13% Re, that is comparable to prior studies of Sr2CrReO6, while Cr steadily replaces Re on the other octahedral site. As x approaches 0.5, long-range Cr/Re ordering drops precipitously. Analysis of X-ray powder diffraction peak shapes reveals antiphase boundaries, associated with Cr/Re ordering, the concentration of which increases steadily with increasing x. Neutron powder diffraction studies confirm antiferromagnetic coupling between antisite Cr3+ ions and Cr3+ ions that occupy the normal sites, leading to site-dependent ferrimagnetic ordering. Density functional theory calculations indicate that chromium maintains a +3 oxidation state across the series, while the oxidation state of rhenium increases with increasing x. Calculations are also used to explore the energies of competing magnetic ground states. Except for the most chromium-rich compositions (x ≈ 0.5), site-dependent ferrimagnetism is retained with only a modest reduction in TC. The saturation magnetization steadily decreases as the chromium content increases due to a combination of Cr/Re antisite disorder and antiphase boundaries.

3.
Nanoscale ; 15(42): 17045-17054, 2023 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-37846775

RESUMO

One of the challenging issues in the formation of atomic wires in break-junction experiments is the formation of stable monoatomic chains of reasonable length. To address this issue, in this study, we present a combination of unsupervised and supervised machine learning models trained on the experimentally measured conductance traces, with a goal to develop a microscopic understanding. Applying a machine learning model to two independent data sets from two different samples containing 72 000 and 90 000 conductance-displacement traces of single-atomic junctions, respectively, we first obtain the optimum conditions of bias and the stretching rate for the formation of chains of length > 4 Å. A deep learning method is subsequently applied for the classification of individual breaking traces, leading to the identification of trace features related to long-chain formation. Further investigation by ab initio molecular dynamics simulations provides a molecular-level understanding of the problem.

4.
Phys Chem Chem Phys ; 25(6): 4667-4679, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36723207

RESUMO

The three well-known orderings of the two constituting atomic species in a bimetallic nano-alloy - core-shell, Janus and mixed structural patterns - may be interconvertible depending on the synthesis conditions. Using first principles electronic structure calculations in the present work, we look for the microscopic origin for such structural transformation considering eight Pd-related bimetallic nano-alloys. Our analysis shows that it is the change in atom-atom covalency that is responsible for such structural transformation. Our study also reveals that the three patterns are distinctly identified in terms of total orbital hybridization. Finally, we have analyzed the trend in the relative catalytic activity for the three structures of each bimetallic nano-alloy using the d-band model. Our analysis indicates that the trend in the catalytic activity for the bimetallic Pd-X nano-alloys seems to be intermediate to those of the pristine Pd and Pt nano-clusters possessing similar structure and equal number of total atoms. Among the studied binary nano-alloys, the bimetallic Pd-Ni nano-alloy appears as the most suitable binary pair to develop a non-Pt catalyst.

5.
Materials (Basel) ; 15(20)2022 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-36295129

RESUMO

The appearance of electrically neutral water molecules in the structure of cobalt dinitrate dihydrate, Co(NO3)2⋅2H2O, drastically changes its magnetic properties as compared to its waterless counterpart, Co(NO3)2. The title compound shows Ising-like behavior reflected in its thermodynamic properties. It experiences long-range antiferromagnetic order at TN = 20.5 K and metamagnetic transition at µ0HC = 0.76 T. First-principles calculations produce the values of leading exchange interactions J1 ~ 10 K and J2 ~ 0.5 K and single-ion anisotropy D ~ 1 K which allows us to consider Co(NO3)2⋅2H2O as a quasi-two-dimensional magnetic system.

6.
Phys Chem Chem Phys ; 24(17): 10201-10209, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35420090

RESUMO

A computational study of the light-induced excited spin-state trapping (LIESST) in a number of Fe(II) spin crossover complexes, coordinated by monodentate, bidentate and multidentate ligands is carried out, with the goal to uncover the trend in the low temperature relaxation rate. A nine order of magnitude change in low temperature relaxation rate is observed among the complexes. The trend is rationalized in terms of the change in metal-ligand covalency, numerically estimated by the crystal orbital Hamiltonian population, thus influencing the back donation or delocalization of the electrons from the low-lying Fe(II)-centered molecular orbital to the empty low-lying ligand-centered π* antibonding molecular orbitals.

7.
Chembiochem ; 23(9): e202200109, 2022 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-35225409

RESUMO

Drug delivery to a target without adverse effects is one of the major criteria for clinical use. Herein, we have made an attempt to explore the delivery efficacy of SDS surfactant in a monomer and micellar stage during the delivery of the model drug, Toluidine Blue (TB) from the micellar cavity to DNA. Molecular recognition of pre-micellar SDS encapsulated TB with DNA occurs at a rate constant of k1 ∼652 s-1 . However, no significant release of encapsulated TB at micellar concentration was observed within the experimental time frame. This originated from the higher binding affinity of TB towards the nano-cavity of SDS at micellar concentration which does not allow the delivery of TB from the nano-cavity of SDS micelles to DNA. Thus, molecular recognition controls the extent of DNA recognition by TB which in turn modulates the rate of delivery of TB from SDS in a concentration-dependent manner.


Assuntos
DNA , Micelas , Genômica , Análise Espectral , Tensoativos
8.
Sci Rep ; 11(1): 21764, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34741050

RESUMO

Understanding magnetism in multiple magnetic sublattice system, driven by the interplay of varied nature of magnetic exchanges, is on one hand challenging and on other hand intriguing. Motivated by the recent synthesis of AA[Formula: see text]BB[Formula: see text]O[Formula: see text] double double perovskites with multiple magnetic ions both at A- and B-sites, we investigate the mechanism of magnetic behavior in these interesting class of compounds. We find that the magnetism in such multiple sublattice compounds is governed by the interplay and delicate balance between two distinct mechanisms, (a) kinetic energy-driven multiple sublattice double exchange mechanism and (b) the conventional super-exchange mechanism. The derived spin Hamiltonian based on first-principles calculations is solved by classical Monte Carlo technique which reproduces the observed magnetic properties. Finally, the influence of off-stoichiometry, as in experimental samples, is discussed. Some of these double double perovskite compounds are found to possess large total magnetic moment and also are found to be half-metallic with reasonably high transition temperature, which raises the hope of future applications of these large magnetic moment half-metallic oxides in spintronics and memory devices.

9.
ChemMedChem ; 16(24): 3739-3749, 2021 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-34550644

RESUMO

Functionalized nanoparticles reveal new frontiers in therapeutics and diagnostics, simultaneously referred to as theranostics. Functionalization of an inorganic nanoparticle (NP) with an organic ligand determines the interaction of the functionalized NPs with various cellular components, leading to the desired therapeutic effect, while diminishing adverse side effects. Apart from the therapeutic effect of the nanoparticles, other physical properties of the organic-inorganic complex (nanohybrid) including fluorescence, X-ray or MRI contrast offer diagnosis of the anomalous target cell. In this study we functionalized Mn3 O4 NPs with organic citrate (C-Mn3 O4 ) and folic acid (FA-Mn3 O4 ) ligands and investigated their antimicrobial activities using Staphylococcus hominis as a model bacteria, which can be remediated through their membrane rupture. While high-resolution transmission microscopy (HR-TEM), XRD, DLS, absorbance and fluorescence spectroscopy were used for structural characterisation of the functionalised NPs, zeta potential measurements and temperature-dependent reactive oxygen speices (ROS) generation reveal their drug action. We used high-end density functional theory (DFT) calculations to rationalise the specificity of the drug action of the NPs. Picosecond-resolved FRET studies confirm the enhanced affinity of FA-Mn3 O4 to the bacteria relative to C-Mn3 O4 , leading to enhanced antimicrobial activity. We have shown that the functionalised nanoparticles offer significant X-ray contrast in in-vitro studies, indicating the FA-Mn3 O4 NPs to be a potential theranostic agent against bacterial infection.


Assuntos
Antibacterianos/farmacologia , Teoria da Densidade Funcional , Staphylococcus hominis/efeitos dos fármacos , Antibacterianos/química , Ácido Cítrico/química , Ácido Cítrico/farmacologia , Relação Dose-Resposta a Droga , Difusão Dinâmica da Luz , Ácido Fólico/química , Ácido Fólico/farmacologia , Compostos de Manganês/química , Compostos de Manganês/farmacologia , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Transmissão , Estrutura Molecular , Nanopartículas/química , Óxidos/química , Óxidos/farmacologia , Espectrometria de Fluorescência , Relação Estrutura-Atividade , Nanomedicina Teranóstica , Difração de Raios X
10.
Molecules ; 26(6)2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33802160

RESUMO

In recent times, ab initio density functional theory has emerged as a powerful tool for making the connection between models and materials. Insulating transition metal oxides with a small spin forms a fascinating class of strongly correlated systems that exhibit spin-gap states, spin-charge separation, quantum criticality, superconductivity, etc. The coupling between spin, charge, and orbital degrees of freedom makes the chemical insights equally important to the strong correlation effects. In this review, we establish the usefulness of ab initio tools within the framework of the N-th order muffin orbital (NMTO)-downfolding technique in the identification of a spin model of insulating oxides with small spins. The applicability of the method has been demonstrated by drawing on examples from a large number of cases from the cuprate, vanadate, and nickelate families. The method was found to be efficient in terms of the characterization of underlying spin models that account for the measured magnetic data and provide predictions for future experiments.

11.
Inorg Chem ; 60(6): 4068-4075, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33661608

RESUMO

In this paper, a comparative structural, dielectric, and magnetic study of two langasite compounds Ba3TeCo3P2O14 (absence of lone pair) and Pb3TeCo3P2O14 (Pb2+ 6s2 lone pair) have been carried out to precisely explore the development of room temperature spontaneous polarization in the presence of a stereochemically active lone pair. In the case of Pb3TeCo3P2O14, mixing of both Pb 6s with Pb 6p and O 2p helps the lone pair to be stereochemically active. This stereochemically active lone pair brings a large structural distortion within the unit cell and creates a polar geometry, while the Ba3TeCo3P2O14 compound remains in a nonpolar structure due to the absence of any such effect. Consequently, polarization measurement under varying electric fields confirms room temperature ferroelectricity for Pb3TeCo3P2O14, which was not the case for Ba3TeCo3P2O14. A detailed study was carried out to understand the microscopic mechanism of ferroelectricity, which revealed the exciting underlying activity of a polar TeO6 octahedral unit as well as Pb-hexagon.

12.
Adv Healthc Mater ; 10(7): e2001736, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33326181

RESUMO

The potentiality of nano-enzymes in therapeutic use has directed contemporary research to develop a substitute for natural enzymes, which are suffering from several disadvantages including low stability, high cost, and difficulty in storage. However, inherent toxicity, inefficiency in the physiological milieu, and incompatibility to function in cellular enzyme networks limit the therapeutic use of nanozymes in living systems. Here, it is shown that citrate functionalized manganese-based biocompatible nanoscale material (C-Mn3 O4 NP) efficiently mimics glutathione peroxidase (GPx) enzyme in the physiological milieu and easily incorporates into the cellular multienzyme cascade for H2 O2 scavenging. A detailed computational study reveals the mechanism of the nanozyme action. The in vivo therapeutic efficacy of C-Mn3 O4 nanozyme is further established in a preclinical animal model of Huntington's disease (HD), a prevalent progressive neurodegenerative disorder, which has no effective medication to date. Management of HD in preclinical animal trial using a biocompatible (non-toxic) nanozyme as a part of the metabolic network may uncover a new paradigm in nanozyme based therapeutic strategy.


Assuntos
Antioxidantes , Manganês , Animais , Materiais Biocompatíveis
13.
ACS Appl Bio Mater ; 4(7): 5485-5493, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35006721

RESUMO

Attachment of microbial bodies including the corona virus on the surface of personal protective equipment (PPE) is found to be potential threat of spreading infection. Here, we report the development of a triboelectroceutical fabric (TECF) consisting of commonly available materials, namely, nylon and silicone rubber (SR), for the fabrication of protective gloves on the nitrile platform as model wearable PPE. A small triboelectric device (2 cm × 2 cm) consisting of SR and nylon on nitrile can generate more than 20 V transient or 41 µW output power, which is capable of charging a capacitor up to 65 V in only ∼50 s. The importance of the present work relies on the TECF-led antimicrobial activity through the generation of an electric current in saline water. The fabrication of TECF-based functional prototype gloves can generate hypochlorite ions through the formation of electrolyzed water upon rubbing them with saline water. Further, computational modelling has been employed to reveal the optimum structure and mechanistic pathway of antimicrobial hypochlorite generation. Detailed antimicrobial assays have been performed to establish effectiveness of such TECF-based gloves to reduce the risk from life-threatening pathogen spreading. The present work provides the rationale to consider the studied TECF, or other materials with comparable properties, as a material of choice for the development of self-sanitizing PPE in the fight against microbial infections including COVID-19.


Assuntos
Anti-Infecciosos/química , Eletricidade , Equipamento de Proteção Individual , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , COVID-19/patologia , COVID-19/prevenção & controle , COVID-19/virologia , Humanos , Nylons/química , Equipamento de Proteção Individual/microbiologia , Equipamento de Proteção Individual/virologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/metabolismo , Reciclagem , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Elastômeros de Silicone/química , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo
14.
ACS Appl Bio Mater ; 4(7): 5471-5484, 2021 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35006728

RESUMO

Centers for Disease Control and Prevention (CDC) warns the use of one-way valves or vents in face masks for potential threat of spreading COVID-19 through expelled respiratory droplets. Here, we have developed a nanoceutical cotton fabric duly sensitized with non-toxic zinc oxide nanomaterial for potential use as a membrane filter in the one-way valve for the ease of breathing without the threat of COVID-19 spreading. A detailed computational study revealed that zinc oxide nanoflowers (ZnO NFs) with almost two-dimensional petals trap SARS-CoV-2 spike proteins, responsible to attach to ACE-2 receptors in human lung epithelial cells. The study also confirmed significant denaturation of the spike proteins on the ZnO surface, revealing removal of the virus upon efficient trapping. Following the computational study, we have synthesized ZnO NF on a cotton matrix using a hydrothermal-assisted strategy. Electron-microscopic, steady-state, and picosecond-resolved spectroscopic studies confirm attachment of ZnO NF to the cotton (i.e., cellulose) matrix at the atomic level to develop the nanoceutical fabric. A detailed antimicrobial assay using Pseudomonas aeruginosa bacteria (model SARS-CoV-2 mimic) reveals excellent antimicrobial efficiency of the developed nanoceutical fabric. To our understanding, the nanoceutical fabric used in the one-way valve of a face mask would be the choice to assure breathing comfort along with source control of COVID-19 infection. The developed nanosensitized cloth can also be used as an antibacterial/anti CoV-2 washable dress material in general.


Assuntos
Anti-Infecciosos/química , COVID-19/prevenção & controle , Nanoestruturas/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , COVID-19/virologia , Fibra de Algodão/análise , Humanos , Máscaras , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/metabolismo , Reciclagem , Aerossóis e Gotículas Respiratórios/virologia , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/isolamento & purificação , SARS-CoV-2/metabolismo , Glicoproteína da Espícula de Coronavírus/química , Glicoproteína da Espícula de Coronavírus/metabolismo , Óxido de Zinco/química
15.
ACS Omega ; 5(40): 25582-25592, 2020 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-33073084

RESUMO

The naturally occurring polyphenolic compound curcumin has shown various medicinal and therapeutic effects. However, there are various challenges associated with curcumin, which limits its biomedical applications, such as its high degradation rate and low aqueous solubility at neutral and alkaline pH. In the present study, efforts have been directed towards trying to resolve such issues by encapsulating curcumin inside the micelles formed by imidazolium-based surface-active ionic liquid (SAIL). The shape and size of the micelles formed by the SAIL have been characterized by using DLS analysis as well as TEM measurements. The photo-physics of curcumin in the presence of ionic liquid (IL) and also with the addition of salt (NaCl) has been explored by using different optical spectroscopic tools. The time-dependent absorption studies have shown that there is relatively higher suppression in the degradation rate of curcumin after encapsulation by the imidazolium-based SAIL in an aqueous medium. The TCSPC studies have revealed that there is deactivation in the nonradiative intramolecular hydrogen transfer process of curcumin in the presence of IL micelles as well as with the addition of salt. Furthermore, the time-dependent fluorescence anisotropy measurement has been carried out to figure out the location of curcumin inside the micellar system. In order to correlate all experimental findings, density functional theory (DFT) and classical molecular dynamics (MD) simulations at neutral pH media have been performed. It has been found that the van der Waals force of interactions plays a major role in the stabilization of curcumin in the micelles rather than the coulombic forces. It also has been observed that the van der Waals interactions remain unaffected in the presence of salt. However, as revealed by the MD simulation results, the micelles are found to be more compact in size after the addition of salt. The RMSD results show that the micelles formed by the SAIL achieve greater stability after a particular time constraint. Our results have divulged that the SAIL could act as a promising drug delivery system.

16.
ACS Omega ; 5(37): 24081-24094, 2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32984730

RESUMO

A series of dispiro[indoline-3,2'-pyrrolidine-3',3″-indolines] was synthesized via a multicomponent polar [3 + 2] cycloaddition (32CA) reaction of isatin derivatives, sarcosine and (E)-3-(2-oxo-2-(pyren-1-yl)ethylidene)indolin-2-one derivatives. The regio- and stereochemistries of the cycloadducts were established on the basis of one-dimensional (1D) (1H-, 13C-, 13C-CRAPT NMR) and two-dimensional (2D) homonuclear and heteronuclear correlation NMR spectrometry experiments (1H-1H gDQFCOSY, 13C-1H-HSQCAD, 13C-1H-HMBCAD, 1H-1H-ROESYAD). The molecular mechanism and regio- and stereoselectivities of the cycloaddition (CA) reaction have been investigated utilizing a density functional theory (DFT) method and were thoroughly explained based on the transition-state stabilities and global/local electrophilicity/nucleophilicity reactivity indices of the reactants.

17.
Phys Rev Lett ; 125(2): 026401, 2020 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-32701347

RESUMO

The binary intermetallic materials, M_{3}Sn_{2} (M=3d transition metal) present a new class of strongly correlated systems that naturally allows for the interplay of magnetism and metallicity. Using first principles calculations we confirm that bulk Fe_{3}Sn_{2} is a ferromagnetic metal, and show that M=Ni and Cu are paramagnetic metals with nontrivial band structures. Focusing on Fe_{3}Sn_{2} to understand the effect of enhanced correlations in an experimentally relevant atomistically thin single kagome bilayer, our ab initio results show that dimensional confinement naturally exposes the flatness of band structure associated with the bilayer kagome geometry in a resultant ferromagnetic Chern metal. We use a multistage minimal modeling of the magnetic bands progressively closer to the Fermi energy. This effectively captures the physics of the Chern metal with a nonzero anomalous Hall response over a material relevant parameter regime along with a possible superconducting instability of the spin-polarized band resulting in a topological superconductor.

18.
Soft Matter ; 16(12): 3050-3062, 2020 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-32133476

RESUMO

Enzymes are dynamical macromolecules and their conformation can be altered via local fluctuations of side chains, large scale loop and even domain motions which are intimately linked to their function. Herein, we have addressed the role of dynamic flexibility in the catalytic activity of a thermostable enzyme almond beta-glucosidase (BGL). Optical spectroscopy and classical molecular dynamics (MD) simulation were employed to study the thermal stability, catalytic activity and dynamical flexibility of the enzyme. An enzyme assay reveals high thermal stability and optimum catalytic activity at 333 K. Polarization-gated fluorescence anisotropy measurements employing 8-anilino-1-napthelenesulfonic acid (ANS) have indicated increasing flexibility of the enzyme with an increase in temperature. A study of the atomic 3D structure of the enzyme shows the presence of four loop regions (LRs) strategically placed over the catalytic barrel as a lid. MD simulations have indicated that the flexibility of BGL increases concurrently with temperature through different fluctuating characteristics of the enzyme's LRs. Principal Component Analysis (PCA) and the Steered Molecular Dynamics (SMD) simulation manifest the gatekeeper role of the four LRs through their dynamic fluctuations surrounding the active site which controls the catalytic activity of BGL.


Assuntos
Prunus dulcis/enzimologia , beta-Glucosidase/química , Domínio Catalítico , Estabilidade Enzimática , Simulação de Dinâmica Molecular , Conformação Proteica , Estrutura Secundária de Proteína , Prunus dulcis/química , Temperatura , Trifolium/química , Trifolium/enzimologia
19.
RSC Adv ; 10(64): 38890-38899, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-35518422

RESUMO

The properties of nanomaterials generated by external stimuli are considered an innovative and promising replacement for the annihilation of bacterial infectious diseases. The present study demonstrates the possibility of getting the antibiotic-like drug action from our newly synthesized nanohybrid (NH), which consists of norfloxacin (NF) as the photosensitive material covalently attached to the ZnO nanoparticle (NP). The synthesized NH has been characterized using various microscopic and spectroscopic techniques. Steady state fluorescence and time-correlated single photon counting (TCSPC)-based spectroscopic studies demonstrate the efficient electron transfer from NF to ZnO. This enhances the reactive oxygen species (ROS) production capability of the system. First principles density functional theory has been calculated to gain insight into the charge separation mechanism. To explore the electron densities of the occupied and unoccupied levels of NH, we have verified the nature of the electronic structure. It is observed that there is a very high possibility of electron transfer from NF to ZnO in the NH system, which validates the experimental findings. Finally, the efficacy of NH compared to NF and ZnO has been estimated on the in vitro culture of E. coli bacteria. We have obtained a significant reduction in the bacterial viability by NH with respect to control in the presence of light. These results suggest that the synthesized NH could be a potential candidate in the new generation alternative antibacterial drugs. Overall, the study depicts a detailed physical insight for nanohybrid systems that can be beneficial for manifold application purposes.

20.
Phys Chem Chem Phys ; 21(37): 21128-21135, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31528915

RESUMO

In search of new candidates for two-dimensional ferromagnets, we consider boronated monolayer holey graphene (C2B), akin to recently synthesized and extensively studied nitrogenated monolayer holey graphene (C2N). In contrast to C2N which is semiconducting and nonmagnetic, our first-principles calculations show that C2B is metallic and ferromagnetic. The microscopic origin of this interesting behavior is found to be related to the hole doping of π-π* network of C-B which produces metallicity while the unpaired electron on the dangling bond of sp2 hybridized state of two-coordinated B produces magnetism. Calculated cohesive energy of boronated holey graphene indicates that the formation of this structure is energetically feasible as is the case with its nitrogenated counterpart. The dynamic and thermal stability of the predicted boronated holey graphene are checked in terms of phonon calculations and finite temperature molecular dynamics simulations. We further investigate the electronic and magnetic properties of embedded transition-metal single atom and pairs on C2B and C2N structures.

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