Journal of Chemical Sciences最新文献

Atoms in every solid are tied up with chemical bonds and are vibrating constantly with thermal energy, even when the material appears perfectly still. These chemical bonds and atomic arrangements are the primary deciding factors for the observed physical properties of the materials. The collective quantized vibrations of atoms are called phonons, and they play a central role in how electrons move, how light interacts with materials, and how heat transfers through the solids. Inorganic halides are promising materials to understand the modified physical properties arising because of dynamics of the atomic arrangements and anharmonicity of the chemical bonds. Di-thallium silver tri-iodide (Tl₂AgI₃) is one such example of solid with zero-dimensional clusters showcasing a new region of wave like (non-diffusive) heat transport, breaking the conventional understanding of particle like thermal propagation. Understanding this new mechanism is important for the development of technologies ranging from thermoelectric energy conversion to thermal managements in micro-nano-electronics and quantum devices.

Graphical abstract

Wave-like coherent heat flow in strongly anharmonic solids offers new pathways for designing next-generationthermal insulators

Chemical reactivity within DFT (CRDFT), also known as conceptual DFT (CDFT), provides a theoretical framework for understanding chemical reactivity through a set of descriptors derived from the electronic structure theory of matter. In this study we present PyCRDFT, a Python package developed to compute CDFT-based reactivity descriptors. The package extends the atomic simulation environment (ASE) atoms object to incorporate electronic properties necessary for descriptor evaluation and supports multiple models, including the Parr–Pearson model, the Two-Parabolas model, and several other formulations. PyCRDFT facilitates the automated calculation of chemical potential, hardness, softness, electrophilicity, nucleophilicity, Fukui functions, and other global and local reactivity indexes. It also enables interfacing with electronic structure codes for property calculations, drawing inspiration from ASE and the developing Atomic Simulation Recipes framework. To validate its implementation, we tested PyCRDFT on benchmark charge-transfer reactions, reproducing values reported in the literature. In addition, PyCRDFT offers automation tools for large-scale calculations, including scheduling, batch processing, and systematic reactivity analysis, making it a versatile tool for computational chemists. The code is openly available on GitLab (https://gitlab.com/izxle/pycrdft) and is open to collaboration.

Lipid bilayers form topologically distinct phases depending on their composition, which regulate biological functions and define material properties. Cholesterol profoundly influences the fluid-to-gel phase transition in model phospholipid bilayers; however, its impact on the pre-transition ripple phase remains less defined and debated. Here we employed extensive all-atom simulations of pure dipalmitoylphosphatidylcholine (DPPC) and DPPC–cholesterol bilayers (with 15–30 mol% of cholesterol) at 30°C to investigate the rippling characteristics and cholesterol’s effect on their stability and organization in a concentration-dependent manner. Our results delineate the spontaneous formation of an asymmetric ripple pattern in the DPPC bilayer, having a periodic array of gel-like “major” and fluid-like “minor” arms. While the major arm is thick and ordered, and the minor arm is thinner and disordered with significant acyl chain splay and interdigitation, resulting in localized loss of bilayer structure and corrugated surface. Incorporation of cholesterol removes interdigitation and reduces the proportion of highly disordered lipids due to the ordering effect while also impeding acyl chain crystallization. At 15 mol%, cholesterol shows greater tendency to accumulate into relatively disordered domains that coexist with cholesterol-poor ordered domains. Thus, the peristaltic asymmetry of ripple pattern in absence of cholesterol transforms into symmetric ripple keeping the bilayer architecture intact. With increasing cholesterol concentration between 20 and 25 mol%, ripple periodicity causing bilayer undulation decreases gradually and at 30 mol% the bilayer turns into lamellar structure with homogeneous liquid-ordered phase and uniform cholesterol distribution. The present work comprehensively shows the effects of varying cholesterol concentrations on ripple nature and architecture of DPPC bilayer, and provides detailed atomistic insights into how cholesterol modulates the lipid organizations of different domains, acyl chain conformations, and lipid–lipid interactions driving to such transformation, adding to bridge the current gap in understanding cholesterol’s role in ripple phase regulation.

Graphical abstract

We characterized the ripple configuration of DPPC bilayer, which consists of a gel like major domain and also fluid like minor domain with interdigitation between leaflets and highly melted fatty acid chains. With addition of cholesterol, on concentration dependent manner, the ripple pattern of DPPC disrupts and with gradual addition of cholesterol the bilayer transforms into liquid-ordered phase.

Herein, we have studied the fluorescence resonance energy transfer (FRET) phenomena between deep eutectic solvents (DES), derived from methyltriphenylphosphonium chloride/bromide (MTPC/MTPB) and piperonyl alcohol (PPA), and acceptor dye, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM). The DESs exhibit excellent intrinsic fluorescence emission, making them suitable for use as FRET donors. The fluorescent DES and DCM, meet the spectroscopic requirements necessary for a resonance energy transfer (RET) event to occur. Both steady-state and time-resolved fluorescence spectroscopy studies demonstrate significant FRET between the donor and acceptor. Furthermore, a decrease in the donor's fluorescence lifetime and the appearance of a rise component in the acceptor's fluorescence decay upon addition of the acceptor have been observed, which are definitive indicators of FRET. The estimated donor-acceptor distances for the MTPC-PPA and MTPB-PPA DESs have been found to be 27.41 Å and 26.93 Å, respectively. Since the donor-acceptor distances in both systems are quite similar, this suggests that their FRET efficiencies are also comparable, at approximately 85%. This finding suggests that the choice of anion in the DESs has minimal impact on its ability to transfer energy to the DCM dye. Therefore, the present study demonstrates a hitherto unobserved energy transfer phenomenon between fluorescent DESs and an acceptor dye.

Graphical abstract

This study reports a novel FRET phenomenon involving intrinsically fluorescent deep eutectic solvents (DESs), composed of methyltriphenylphosphonium halide (Cl- or Br-) and piperonyl alcohol, acting as donors, and the acceptor dye 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran. The findings demonstrate that these DESs serve as effective FRET donors due to their significant intrinsic fluorescence emission.

Poly (N-isopropylacrylamide) (poly-NIPAM) microgel particles are soft spheres with a core-shell structure having a dense core and a thin shell consisting of less cross-linked polymers and dangling polymer chains (here after referred to as hairs). These poly-NIPAM particles with core-shell structure and dangling polymer chains are referred to as CPNIPAM soft-spheres. Poly-NIPAM microgel soft-spheres with homogeneous core (HPNIPAM) are also synthesised by altering synthesis conditions to unravel the role of hairs on the phase behaviour, particle dynamics and the yielding behaviour of microgel suspensions under dense conditions (i.e., volume fractions ϕ ≥ 0.68). This article presents results obtained from dynamic light scattering (DLS), and rheology measurement on dense disordered (glassy) structures of poly-NIPAM microgel suspensions with volume fractions, ϕ < 0.68 and under over packed (ϕ > 0.68) conditions. We discuss two important results obtained on dense CPNIPAM microgel colloidal glasses, namely, (i) two-step yielding and (ii) sub-diffusive behaviour at short-time scales. The entanglement of hairs between neighbouring soft spheres under dense (also referred to as over packed) conditions is shown to be responsible for the above-mentioned results. To provide unambiguous evidence in favour of the existence of entanglements, we prepared HPNIPAM particles that have only homogeneous polymer core and no hairs. Under over packed conditions HPNIPAM suspensions showed single step yielding and absence of sub-diffusive behaviour at short times, respectively. These observations provide evidence in support of entanglements between hairs which are responsible for the unusual behaviour of dense microgel colloidal glasses of CPNIPAM particles. Molecular dynamics and oscillatory shear simulations have been carried out using multi-Hertzian (MH) pair-potential proposed by Bergman et al. (Nat. Commun. 2018, 9, 5039) for core-shell structured thermo-responsive poly-NIPAM microgel suspensions. We show that though MH pair-potential explains the phase behaviour of microgel suspensions qualitatively, it fails to explain the above-mentioned experimental observations. The need for improving MH pair-potential that accounts for the role of hairs and their entanglements under dense conditions to explain experimental observations reported over a volume fraction ranging from 0.80 to 0.89 is discussed.

Graphical abstract

Dyes are a significant contributor to water pollution; therefore, effective removal methods are necessary to ensure environmental safety and water purification. Biopolymer-based films provide a sustainable and economical solution for dye adsorption, with research increasingly focused on modifying surface features to enhance dye-film interaction. However, the potential of acryloyloxy tamarind kernel powder (ARTKP)-based nanometallic film for dye adsorption remains underexplored. This study addresses the existing research gap by developing an eco-friendly nanometallic film (ENMF) with a super-adsorptive surface for effective dye molecule adhesion and enhanced UV absorption capacity. The adsorptive ENMF was fabricated via the solvent casting method through ex-situ incorporation of TiO₂ nanoparticles into the ARTKP/GG matrix. Experimental and analytical evaluation confirmed that the ENMF exhibits significantly enhanced properties, including an increase in thermal stability and crystallinity, compared to ARTKP biocomposites. ENMF demonstrated a strong adsorption capacity for the methylene blue dye, exhibiting pseudo-first-order kinetics behaviour. It also showed remarkable UV absorption efficiency and efficient biodegradability. These results highlight the ARTKP/GG@TiO₂ ENMF’s potential as a material that holds promise for removing dyes from the aquatic environment.

Graphical abstract

A novel ARTKP/GG@TiO₂ eco-friendly nanometallic film (ENMF) was developed via solvent casting with ex-situ TiO₂ NPs incorporation. The ENMF exhibits efficient photocatalytic adsorption of methylene blue dye and strong UV absorption in aqueous media, highlighting its potential as a sustainable, multifunctional material for advanced wastewater treatment applications.

Over the last several decades, molecular materials have emerged as an important class within the broader field of materials science and chemistry. The critical impact of the structure of molecular building blocks, as well as their mode of assembly, have been exploited to develop a wide range of functional molecular materials. The most rudimentary level of molecular assembly that can be visualized in this context is the amorphous or crystalline form; their mutual transformations also serve as the basis for various potential applications. This review outlines the basic concepts in this domain and uses several case studies with the diaminodicyanoquinodimethane (DADQ) family of molecules to illustrate or model them. The enhancement and tuning of the fluorescence emission of DADQs, from the solution to the amorphous, to the crystalline states, provide a facile handle for monitoring the assembly modes and their transformations. This has also led to the formulation of fundamental molecular structure–phase correlations. This review is expected to trigger new ideas that leverage even the most basic forms of molecular assembly to achieve useful responses and functions in molecular materials.

Graphical abstract

Following an overview of the development of molecular materials, the relevance of amorphous and crystalline assemblies as well as their reversible interconversions is highlighted. Exploitation of the sensitive changes in the fluorescence emission of diaminodicyanoquinodimethane (DADQ) family of molecules to monitor and model the assemblies and their transformations is discussed.

Gold nanorods, as a type of anisotropic nanoparticles, require uniformity for their properties and applications. Here, we demonstrate the successful preparation of well-dispersed and uniformly shaped GNRs through a two-step seed-mediated growth method by separating the symmetry breaking of seeds from subsequent growth. We determined that adding the first growth solution (Solution A) into the second growth solution (Solution B) after 30 min was optimal, and monitored the growth progress by recording the growth status every 30 min, observing that the growth of Solution A (150 min) and Solution B (210 min) essentially ceased. Furthermore, by adjusting the seed quantity, silver ion content, and pH value of the growth solution in each step, we could tune the wavelength of the localized surface plasmon resonance (LSPR) peak within the range of 668 to 1020 nm. Additionally, the trend of overall electric field intensity variations were determined through finite difference time domain (FDTD) simulations. We believe that this approach will further facilitate practical applications of GNRs research, as these applications rely on the high uniformity of GNRs.

Graphical abstract

Synopsis. We demonstrate the preparation of uniformly shaped gold nanorods through a two-step seed-mediated growth method by separatingthe symmetry breaking of seeds from subsequent growth. By adjusting the seed quantity, Ag⁺ content, and pH value of the growthsolution, we could tune the LSPR from 668 to 1020 nm.

A series of 1H-indazole derivatives were synthesized using hexafluorophosphate azabenzotriazole tetramethyl uronium (HATU) as a coupling agent and evaluated for their dual biological activity against Mycobacterium tuberculosis (Mtb) and non-small cell lung cancer (NSCLC). Molecular docking and molecular dynamics (MD) simulations identified (2,5-dimethoxyphenyl)-(5-nitro-1H-indazol-1-yl)methanone (compound 11) was the most promising candidate, showing stable binding to the InhA enzyme with a binding energy of −9.76 kcal/mol. Compound 11 exhibited strong antitubercular activity (MIC 3.2 µg/mL), potent cytotoxicity against A549 cancer cells (78.45%), and significant anti-inflammatory effect (92.98% edema inhibition at 12h). Other derivatives also demonstrated noteworthy antimycobacterial and anti-inflammatory properties. Molecular mechanics-generalized born surface area (MM-GBSA) and molecular dynamic simulation (MDS) supported the favourable binding affinities and complex stability of the lead compound. Absorption, distribution, metabolism, and excretion (ADME) predictions confirmed drug-likeness with good gastrointestinal absorption and no violations of Lipinski's rule. The combined in silico and in vitro findings highlight the potential of these indazole-based compounds as dual-acting agents for treating multidrug-resistant tuberculosis and NSCLC. Further in vivo studies and mechanistic investigations are warranted to explore their clinical relevance.

Graphical abstract

It was demonstrated that the synthesized derivatives of 1H-indazole using HATU as a coupling agent showed promising antitubercular, analgesic, anti-inflammatory as well as anticancer activity. The compound NDM showed excellent biological activities.