Non-covalent Interaction Analysis Research Articles

Interplay between energy and geometry of parallel-displaced interactions in S8 dimer structures

Elemental sulfur exists in various allotropes, with the most stable form being the cyclic S8 allotrope. Although the orthorhombic α-S8 modification has been extensively studied, there has been no systematic analysis of noncovalent interactions between sulfur rings and their nature, geometries, and energies until now. To achieve this, we conducted a comprehensive study analyzing all crystal structures from the Cambridge Structural Database involving contacts between S8 molecules. Then, we combined those data with high-level quantum chemical calculations. The results revealed that the preferred orientation in the crystal structures is parallel-displaced. Quantum chemical calculations supported this finding, demonstrating that the most stable interaction in the S8 dimer occurs when two molecules adopt a parallel-displaced geometry resembling the one observed in the crystal structures. The interaction in the S8 dimer is very strong, with an energy of −8.70 kcal/mol, calculated at a highly accurate CCSD(T)/CBS level. In this stacking-like geometry, multiple S…S interactions can form, and the NCI analysis indicated an overlap of large surfaces of interacting molecules, significantly contributing to the system's stability. The SAPT2+(3) energy decomposition analysis showed that the predominant attractive force between two S8 molecules is dispersion, although the electrostatic component is also significant. This research holds importance in understanding the molecular assembly in solid sulfur and in systems that exhibit interactions between S8 molecules.

Interaction behavior study of HCl on (ZnS)n (n = 1–12) clusters and HCl effect on Hg0 adsorption

AbstractThe interaction behavior of HCl and (ZnS)n (n = 1–12) clusters and HCl effect on Hg0 adsorbed by (ZnS)n have been studied theoretically. The combined genetic algorithm and density functional theory (GA‐DFT) method has been used to obtain the structures of (ZnS)nHCl and (ZnS)nHgHCl (n = 1–12) clusters. The structural properties of (ZnS)nHCl and (ZnS)nHgHCl have been analyzed. The adsorption energies and interaction energies have been calculated. Bond length and bond order analysis has revealed that SH and ZnCl bonds form after HCl adsorbed on (ZnS)n clusters, while Hg0 can only weakly bind with (ZnS)nHCl clusters. According to thermodynamic adsorption analysis, the formation of (ZnS)nHCl clusters from (ZnS)n and HCl are spontaneous because of their negative Gibbs free energy changes. The formation of (ZnS)nHgHCl from (ZnS)nHCl and Hg are nonspontaneous for n = 1–4 and 9, and the Gibbs free energy changes have small negative values for other sizes. Electron localization function and noncovalent interaction (NCI) analysis of (ZnS)10HgHCl manifest that Hg and its nearest Zn form zinc amalgam. Projected density of state study has been performed to obtain the interaction nature of HCl and (ZnS)n clusters and Hg0 adsorption on (ZnS)nHCl clusters. Based on our study, HCl is chemical adsorbed by (ZnS)n clusters except (ZnS)4 cluster. After (ZnS)n adsorbs HCl, Hg0 can physically adsorb on (ZnS)nHCl clusters. The strength of Hg0 on (ZnS)nHCl is comparable to that of Hg0 on (ZnS)n, indicating that HCl can hardly affect the adsorption of Hg0 on ZnS clusters.

Theoretical study of an N-heterocyclic carbene-catalyzed annulation reaction between an enal and a β-silyl enone: Mechanism and origin of stereoselectivity

In this study, the mechanism and origin of the stereoselectivity of an N-heterocyclic carbene (NHC)-catalyzed transformation reaction between an enal and a β-silyl enone are systematically investigated using density functional theory (DFT) at the M06-2X level. Multiple pathways are proposed and studied to identify the most energetically favorable mechanism for the reaction. The calculation results show that the most energetically favorable pathway comprises the following processes: nucleophilic addition of NHC to the Si-face of the enal to form a zwitterionic intermediate, two sequential CsHCO3-assisted intramolecular proton shifts to produce an enolate intermediate, Michael-type addition of the enolate intermediate to the β-silyl enone, ring closure to construct a six-membered ring intermediate, and the dissociation of NHC to release the final product. The reaction between the enolate intermediate and the β-silyl enone is identified as the stereoselectivity-determining step, preferentially generating an RS-configured product. Subsequent atoms-in-molecules (AIM) and noncovalent interaction (NCI) analyses verify that the main factor for inducing stereoselectivity is the higher number of noncovalent intermolecular interactions in the low-energy transition state.

In-Silico Aided Screening and Characterization Results in Stability Enhanced Novel Roxadustat Co-Crystal

Roxadustat (RXD) is an approved drug substances for the treatment of renal anemia. It has poor aqueous solubility and photochemical stability. This study employs a comprehensive approach to enhance the stability and physicochemical properties RXD through coformer selection and characterization. The investigation integrates delta pKa analysis, molecular complementary assessment, molecular electrostatic potential surface analysis, and machine learning techniques to predict potential co-crystal formation and binding interactions between drug molecules and coformers. The co-crystal screening which lead to in a novel RXD-nicotinamide co-crystal (RXD-NA). Experimental characterization underscores the physical and chemical stability of the co-crystals. To elucidate the supramolecular synthons and understand the intermolecular interactions in the RXD-NA co-crystal, Hirshfeld surfaces analysis, quantum theory of atoms in molecules (QTAIM) analysis and non-covalent interaction (NCI) analysis were performed. Computational analysis of photo-isomer formation aligns with experimental observations, further enhancing our understanding of RXD-coformer interactions. RXD-NA co-crystal was found photo-chemically stable as compared to free base API drug substance. This integrated methodology provides a systematic framework for informed co-crystal design, holding promise for optimizing RXD formulations based on molecular interactions and stability considerations. Consequently, this study contributes valuable insights to the field of rational drug design and formulation optimization.

Controlling the Energetic Properties of N-Methylene-C-Linked 4-Hydroxy-3,5-dinitropyrazole- and Tetrazole-Based Compounds via a Selective Mono- and Dicationic Salt Formation Strategy.

In the quest to synthesize high-performing insensitive high-energy density materials (HEDMs), the main challenge is establishing an equilibrium between energy and stability. For this purpose, we explored 4-hydroxy-3,5-dinitropyrazole- and tetrazole-based energetic scaffolds connected via a N-methylene-C bridge. The hydroxy functionality between nitro groups on the pyrazole ring promotes physical stability via inter- and intramolecular hydrogen bonding and contributes to oxygen balance, supporting better energetic performance. Due to two acidic sites (OH and NH) with different reactivities, a series of monocationic and dicationic salts were synthesized, and their overall performance was compared. All compounds synthesized in this study have high physical stability with impact sensitivity >40 J and friction sensitivity >360 N. Monocationic salts were generally found to have better thermal stability with respect to their corresponding dicationic energetic salts, which showed better energetic performance. The salt formation strategy effectively improved the thermal stability of 2 (Td = 168 °C), where most energetic salts have decomposition temperatures higher than 220 °C. All of the compounds were characterized through IR, multinuclear NMR spectroscopy, high-resolution mass spectrometry (HRMS), and elemental analysis. The structure-property relationship was studied using Hirshfeld surface analysis, noncovalent interaction (NCI) analysis, and electrostatic potential studies.

Structural and computational insights into two trimethylenedipyridine co-crystals: Inputs from X-ray diffraction, Hirshfeld surface, PIXEL, QTAIM and NCI plots

Two trimethylenedipyridine co-crystals, [(TMDP)·(H2OBA)] (1) and [(TMDP)·(SUC)] (2) [TMDP = 4, 4′-trimethylenedipyridine, H2OBA = 4,4′-oxybis(benzoic acid), and SUC = succinic acid) were designed, synthesized and their single crystals were grown by slow evaporation technique. The grown crystals were characterized by elemental analysis and UV–Vis spectroscopic technique, and the structures of the grown crystals were elucidated using single-crystal X-ray diffraction analysis. Supramolecular assemblies of co-crystal (1) are stabilized through several intermolecular hydrogen bonds such as O‒H···N, C‒H···O, C‒H···π, as well as π···π interactions whereas for co-crystal (2) only intramolecular hydrogen bonding interaction, O‒H···N is responsible for stabilization of supramolecular network. Hirshfeld surfaces were used to gain additional insight into non-covalent interactions in molecular crystals, and 2D fingerprint plots provided a quantitative analysis of different non-covalent interactions in the crystal structures. The interaction energies of the molecular pairs, as well as the lattice energies of the crystal structures, have been studied using the PIXEL method. The nature and strength of the non-covalent interactions at their (3, –1) bond critical points (BCPs) have been explored using Bader's quantum theory of “Atoms in Molecules” (QTAIM). The non-covalent interactions were further characterized through the NCI plots.

Effect of binding pockets on the kinetics and thermodynamics of Diels-alder reaction in cucurbit-Uril family

Cucurbit-uril (CB-uril) family has witnessed a considerable increase in popularity over the last two decades due to its amazing binding ability which impart broad range of applications. Cucurbit-uril family members exhibit diversity in their binding pocket to accommodate guest molecules of different sizes which in turn impact the remarkable properties of these molecules. Herein, we have studied the influence of encapsulation on the kinetics and thermodynamics of the Diels-Alder reaction. Effects of binding pockets on the Diels-Alder reaction are explored by selecting CBn(n = 5–8)-uril. Bond evolution theory (BET) and non-covalent interaction (NCI) analyses have also been performed to gain insight into electronic distribution along the reaction route as well as bond formation/breakage to understand the mechanism of action and the role of weak/strong interactions between CBn-uril and reaction during the process. Activation energies for Diels-Alder reaction in CBn=6–8-uril (22.63 kcal mol−1, 21.37 kcal mol−1, and 19.45 kcal mol−1, respectively) are significantly lower than that of the bare reaction (25.45 kcal mol−1). While for P-DA reactions, activation energies within CBn=7,8-uril are observed as 19.29 kcalmol−1 and 14.45 kcalmol−1 (cis-1,2-dicyanoethylene), 18.46 kcalmol−1 and 14.65 kcalmol−1 (trans-1,2-dicyanoethylene), and 16.01 kcalmol−1 and 20.86 kcalmol−1 (tetracyanoethylene). CB7-uril has predicted the lowest activation energies for DA reaction with cis-1,2-dicyanoethylene and trans-1,2-dicyanoethylene compared to bare Ea ≈ 20.15 kcalmol−1 and 19.57 kcalmol−1, respectively. By making the reaction more exothermic with ER ≈ -40 kcal mol−1, CB6-uril has the lowest activation energy of ≈ 19.45 kcal mol−1, predicting CBn-uril as an effective cavity for researching the Diels-Alder process.

Intra- and Intermolecular Cation-π Interactions between Onium Salts and Alkynes/Acetylene: Experimental and Theoretical Insights.

Cation-π interactions between various onium salts, alkynes, and acetylene were studied, taking into account the substituents of the triple bond, the nature of the anions, and the polarity of the solvent, through a combination of MP2 calculations and experiments. In an intramolecular setting, these data (including single-crystal X-ray crystallography) concurred with the stability of folded conformers of alkynyl onium salts, even substituted with electron-withdrawing groups. To examine the contribution of these interactions on the alkyne electronic population, a thorough in silico study was carried out using natural bonding orbital analysis of the conformers. Intramolecular interactions from sulfonium salt tethered to phenylalkyne were highlighted, as illustrated above by the computed folded conformation (MP2) along with noncovalent interaction (NCI) analysis. Furthermore, investigations of intermolecular interactions, involving acetylene or phenylacetylene with various onium ions, revealed the high energy interactions of their complexes with phenyldimethylsulfonium chloride, as illustrated above with the complex PhC≡CH/PhMe2SCl (MP2 calculations and NCI analysis).

A stereoselective nontraditional Heck reaction mechanism: Origins of enantioselectivity and diastereoselectivity

Nontraditional Heck-type reactions of C = heteroatomic variants have been a great challenge. Herein, we computationally investigate a nontraditional stereoselective Heck mechanism regarding hydrazone C = N-NH2 by using density functional theory (DFT) methods. Calculations indicate that the total potential barrier of the conversion is 25.6 kcal/mol, which is reasonable to be crossed under the current reaction conditions. Unlike C = C π-bonds, the coordination of C = N with transition metal palladium into a η1-complex is confirmed. A larger π-bond insertion barrier for C = N is required, which is rationalized by frontier molecular orbital (FMO) analysis with a wider LUMO-HOMO energy gap. π-bond insertion is the enantioselectivity determining step of the strategy and that the pathway toward the R-isomer exhibits a much lower energy barrier (24.2 vs 40.1 kcal/mol). π-bond insertion is also the diastereoselective control step with using DBBP ligands. Non-covalent interaction (NCI) analysis confirms that greater spatial hindrance is responsible for the stereoselectivity of the protocol. Meanwhile, calculations show that using an acid-promoted tactic can effectively improve the in situ production of hydrazone and significantly reduce the energy barrier.

Adsorption mechanism of amino acid ionic liquids on the N-doped graphene surface for electrochemical double layer capacitors: A density functional theory study

BackgroundThe interfacial interaction between amino acid ionic liquids (AAILs) and graphene (Graphene and N–Graphene) is crucial for understanding the behavior of electrolytes in supercapacitors and ion–batteries. Studying the adsorption mechanism of AAILs on graphene surfaces is the subject of this work. MethodsIn this study, we employed the density functional theory to reveal adsorption process. The binding energies, thermochemistry, quantum molecular descriptors, charge transfer, quantum theory of atoms in molecules, noncovalent interaction and energy decomposition analysis were investigated. Significant findingsThe adsorption process spontaneously proceeded, and the highest occupied molecular orbital–lowest unoccupied molecular orbital energy gap was reduced slightly upon AAILs adsorption. Nitrogen doping significantly guides the local distribution of electrons and improves the combination of ions, and charge transfer between AAILs and N–Graphene was greater than between AAILs and Graphene. Thus, N–Graphene might exhibit better performance than Graphene. Furthermore, the adsorption was noncovalent in nature, which is crucial to the diffusion of ions in electrolyte–electrode systems. The above results could offer a new angle of view on graphene–AAIL and help in designing novel systems for electrochemistry applications.

Exploring the potential of single-metals (Cu, Ni, Zn) decorated Al12N12 nanostructures as sensors for flutamide anticancer drug

In recent years, scientists have been actively exploring and expanding biosensor technologies and materials to meet the growing societal demands in healthcare and other fields. This study aims to revolutionize biosensors by using density functional theory (DFT) at the cutting-edge B3LYP-GD3BJ/def2tzsvp level to investigate the sensing capabilities of (Cu, Ni, and Zn) doped on Aluminum nitride (Al12N12) nanostructures. Specifically, we focus on their potential to detect, analyze, and sense the drug flutamide (FLU) efficiently. Through advanced computational techniques, we explore molecular interactions to pave the way for highly effective and versatile biosensors. The adsorption energy values of −38.76 kcal/mol, −39.39 kcal/mol, and −39.37 kcal/mol for FLU@Cu–Al12N12, FLU@Ni–Al12N12, and FLU@Zn–Al12N12, respectively, indicate that FLU chemically adsorbs on the studied nanostructures. The reactivity and conductivity of the system follow a decreasing pattern: FLU@Cu–Al12N12 > FLU@Ni–Al12N12 > FLU@Zn–Al12N12, with a band gap of 0.267 eV, 2.197 eV, and 2.932 eV, respectively. These results suggest that FLU preferably adsorbs on the Al12N12@Cu surface. Natural bond orbital analysis reveals significant transitions in the studied system. Quantum theory of atom in molecule (QTAIM) and Non-covalent interaction (NCI) analysis confirm the nature and strength of interactions. Overall, our findings indicate that the doped surfaces show promise as electronic and biosensor materials for detection of FLU in real-world applications. We encourage experimental researchers to explore the use of (Cu, Ni, and Zn) doped on Aluminum nitride (Al12N12), particularly Al12N12@Cu, for biosensor applications.

Hydrocarbons (C8–C12) separation in porous metallocavitand M-PPX (M = Cu, Ag, Au): From computational insight

High throughput computational approach has been employed to investigate the adsorption and separation of C8–C12 hydrocarbons (HCs) on a tube-shaped metallocavitand, pillarplex (PPX). The Cu (I), Ag (I), and Au (I) seamed PPX and their HC complexes has been examined using density functional theory (DFT), proclaiming Cu-PPX has a higher binding affinity with the HCs whereas Ag-PPX is lower. The thermodynamic properties reveal the host–guest complex is stable at ambient condition. Noncovalent interaction (NCI) analysis shows the interaction of guests within the cavity of PPX is mainly attributed by Van der Waals type. The energy decomposition analysis (EDA) enunciates the percentage contribution of dispersion interaction (ΔEdisp) is 59–62%, the electrostatic (ΔEelct) and orbital (ΔEorb) terms have a moderate contribution towards the total binding energy. The Grand canonical Monte Carlo (GCMC) simulation manifests the Cu-PPX and Au-PPX are the ideal hosts with the optimum capacity to store HCs at ambient conditions. The octane uptake is 18.01, 17.50, and 25.31 cm3STP/g in Cu, Ag and Au-PPX and the uptake reduces upon increasing the HC chain length. The isosteric heat of adsorption (Qst) is corroborated with the computed DFT data at ambient setup. The ideal adsorption solution theory (IAST) claims the C8 selectivity in Cu, Ag and Au-PPX is optimum at 298 K and the increasing temperature from 298 K to 323 K, the selectivity of the C9 and C12 in Cu-PPX and Au-PPX, respectively is remarkable after the complete separation of C8. Hence Cu-PPX and Au-PPX is the potential candidate for industrial use to separate the heavy HCs.

Sulfonic acid functionalized monolithic column for high selectivity capillary electrochromatography separation.

A new nano-scale spherical vinyl-functionalized covalent organic polymer (TAPT-DVA-COP) with uniform sizes around 300nm was initially constructed using 2,5-divinyl-1,4-benzaldehyde (DVA) and 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) as monomers. Then, a sulfonic acid (-SO3H) modified COP termed COP-SO3H was developed based on post-sythesis method employing TAPT-DVA-COP as precursor. Capillary electrochromatography (CEC) monolithic columns were fabricated using the physical doping technique to exhibit the application potential of TAPT-DVA-COP and COP-SO3H. Compared to the TAPT-DVA-COP monolithic column, the COP-SO3H monolithic column achieved a highly selective separation between analytes with different properties, including monosubstituted benzenes, alkylbenzenes, hydroxybenzoates, nucleoside bases, and biogenic amines. Non-covalent interaction (NCI) analysis and experimental data show that the synergism of the sulfonic acid group and aromatic moieties on COP-SO3H endows the new stationary phase with diverse interactions, including ion exchange, hydrophobic, π-π and hydrogen bonding. In addition, the COP-SO3H monolithic column exhibited good reproducibility and excellent potential for the determination of hydroxybenzoates in compact powders and alkylbenzenes in effluent samples.

Theoretical investigation of anion perfluorocubane.

In this work, we did a theoretical exploration of C8F8 (Ib) and its anion radical analogue (IIb) in this work. By investigating the thermochemistry of electron capture, we find that the free energy associated with the conversion of C8H8 (Ia) into its anion radical analogue IIa is of the order of + 92.83 kcal.mol-1, while the conversion of Ib into IIb is - 6.42 kcal.mol-1. Therefore, species IIb is thermodynamically more stable than its neutral analogue. Natural bond orbitals (NBO) analyses revealed that compound Ib exhibits a relative electronic stability as a function of intramolecular delocalisations of the type [Formula: see text] of the order of 2.70 kcal.mol-1. Similar delocalizations for Ia are energetically lower (1.45 kcal.mol-1). Topological analyses of compounds Ib and IIb indicate that the addition of an electron to Ib enhances the covalency of the C-C bond, as can be seen by the reduction in the ellipticity of the C-C bond. The opposite is observed for Ia, whose addition of the electron (leading to IIa) reduces the covalency of the C-C bond. By comparing the free and packaged forms of the species, it is found that, in the crystalline form, the system will present greater relative stability due to the dispersive interactions involved, as evidenced by non-covalent interactions (NCI) analysis. Finally, it was possible to verify that the manifestation of the current density with a lower paratropic and less antiaromatic character in Ib and IIb point to C8F8 as a strong candidate for electron capture. Geometry optimization calculations were carried out, for all monomer structures using the hybrid functional B3LYP-D3 and the 6-31+G(d,p) basis set. To determine the formation thermochemistry of the ions, electronic energy corrections was performed using the DLPNO-CCSD(T)/aug-cc-pVTZ/C method. Starting from the optimised forms, shielding, nuclear magnetic resonance (NMR) spectra employing gauge-independent atomic orbital (GIAO), and NBO calculations were performed for these monomers, using the PBE0 functional and the pCSseg-2 atomic basis set. The magnetochemical analysis of ring currents was performed using the GIMIC formalism. For the topological analysis, it was applied the combination DLPNO-CCSD(T)/aug-cc-pVTZ/C, previously used for correcting the electronic energy.

Ab Initio Approach to the Structure, Vibrational Properties, and Electron Binding Energies of H2S∙∙∙SO2.

The present study employs high-level ab initio calculations to investigate the structure, vibrational frequencies, and electronic properties of H2S∙∙∙SO2. The analysis of vibrational frequencies reveals an intramolecular vibrational energy transfer phenomenon, where energy from the stretching modes of H2S is transferred to the ν1s mode of SO2. At the CCSD(T)/aug-cc-pVQZ level, the interaction energy between H2S and SO2 is predicted to be 2.78 kcal/mol. Electron propagator theory calculations yield a HOMO-LUMO gap of 8.24 eV for H2S∙∙∙SO2. Furthermore, by utilizing ab initio results for the adiabatic ionization energy and electron affinity, the electrophilicity of H2S∙∙∙SO2 is estimated to be 2.01 eV. This value is similar to the electrophilicity of SO2, suggesting comparable reactivity and chemical behavior. The non-covalent interaction (NCI) analysis of the H2S∙∙∙SO2 complex emphasizes the significant contribution of non-covalent van der Waals interactions in its energetic stabilization.

Experimental and theoretical investigation of structure activity relationship on L-Lysine Monohydrate for antioxidant efficacy

Comprehensive spectroscopic research has been undertaken to investigate the structural behaviour of the l-lysine monohydrate molecule. The spectral properties of the l-lysine monohydrate molecule in solid phase were examined using Fourier Transform Infrared (FTIR) and Fourier Transform Raman methods. The B3LYP/6–311++G (d, p) computations were used to optimize the structure of the molecule. To provide complete vibrational spectral assignments, vibration energy distribution analysis (VEDA) was used. The Natural bond orbital (NBO) analysis explains the stability and distinct forms of hydrogen bonds with in the molecule. The chemical stability of the molecule is predicted by Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) analysis. Non-Covalent Interaction (NCI) analysis was done to identify weak interactions according to density of electron of the title compound. The fukui function identified the chemical reactivity sites. To predict its antioxidant efficacy, docking studies were done.

Asymmetric reductive carboxylation of N-(2-bromophenyl)-N-methylmethacrylamide with CO2 catalyzed by nickel complex: A theoretical study

To provide guiding information for developing efficient catalysts for CO2 carboxylation, we investigated the mechanism of asymmetric reductive carboxylation of N-(2-bromophenyl)-N-methylmethacrylamide with CO2 catalyzed by a nickel complex using density functional theory (DFT) calculations. The reaction was found to proceed via a multistep and elaborate mechanism. Additionally, CO2 exhibits a preference for inserting into the Ni(I) intermediate rather than Ni(II) intermediate. The noncovalent interaction (NCI) analysis reveals that the π-π stacking interactions and hydrogen bonding interactions lead to the stereoselectivity.

Functionalized boron doped graphene (BGP) as smart nanocarrier for delivery of hydroxyurea (HU) drug

The concerning toxicity associated with hydroxyurea (HU), an anticancer drug used in cancer treatment, has spurred significant attention within the research community over the years. To address this adverse effect, there is a critical need for a smart and targeted drug delivery system (Nano carrier) that can effectively deliver the drug to the tumor site while minimizing side effects for the patient. In this study, we employed density functional theory computations at (DFT)/ωB97XD/6–311++G (d, p) level of theory to evaluate the adsorption properties of functionalized boron-doped graphene (BGP) surfaces, namely COOH@BGP, NH2@BGP, and OH@BGP, for the delivery of the HU anticancer drug. The electronic properties analysis revealed that COOH@BGP/HXU (M2) exhibited the most favorable reactivity with an energy gap value of 5.3756 eV, making it the most reactive surface compared to other complexes investigated. Moreover, a comprehensive natural bond orbital analysis was conducted to investigate hyper-conjugative effects, hybridization, charge transfer, and H-bonding interactions within the systems studied. The results confirmed the following trend: HXU-COOH@BGP (M2) > HXU-OH@BGP (K2) > HXU-NH2@BGP (Q2). Additionally, topological analysis (QTAIM) and Non-covalent interaction (NCI) analysis were performed to ascertain the interaction forces at play. The results strongly support the significant electrostatic force of interaction in the M2 complex, suggesting the presence of hydrogen bond interactions that facilitate the doped surface's ability to bind with HXU and enhance the smooth delivery of the investigated drug. Furthermore, the adsorption studies revealed negative adsorption energy values, indicating favorable adsorption. Among all the analyzed complexes, M2 nanocarrier demonstrated the most suitable characteristics for the delivery of the HXU anticancer drug. These findings hold promise for the development of an efficient and targeted drug delivery system that could potentially mitigate the toxicity associated with HU and enhance cancer treatment outcomes."

Tetrabromidocuprate(II) complexes with diprotonated 1-hydroxy-4methyl-2-(pyridin-2-yl)-5-phenylimidazole and 1-hydroxy-2-(pyridin-2-yl)-4,5,6,7-tetrahydrobenzimidazole ligands: Relationship between the structure and magnetic properties

Two new tetrabromidocuprate(II) complexes with diprotonated 1-hydroxy-2-(pyridin-2-yl)-4,5,6,7-tetrahydrobenzimidazole (1) and 1-hydroxy-4methyl-2-(pyridin-2-yl)-5-phenylimidazole (2) were synthesized and their structure established from single-crystal X-ray data. Compounds crystallized in the monoclinic space groups P21/n and P21/c, respectively, where tetrabromidocuprate anions formed magnetic chains as inferred from the distances between the halide ions of different [CuBr4]2− units. Magnetization measurements showed that both compounds behave as well-isolated uniform S = 1/2 antiferromagnetic chains described by the one-dimensional Heisenberg antiferromagnetic model with intra-chain exchange interaction 2 J = 23 K (1) and 2 J = 33 K (2) (the Hamiltonian Hˆ=2J∑SˆiSˆi+1). Electron paramagnetic resonance, optical absorption, and density functional theory investigations provided complementary results for 1 and 2. A calculation of exchange coupling constants gave values of 2 J = 24 K (1) and 2 J = 39 K (2), in good agreement with the experiment. The quantum theory of atoms in molecules and non-covalent interaction analyses showed that halogen bonding determined the exchange interaction between [CuBr4]2− units in magnetic chains of these cation–anion compounds.

Metals (B, Ni) encapsulation of graphene/PEDOT hybrid materials for gas sensing applications: A computational study

Recent attention has been directed towards the role of greenhouse gases, including methane (CH4), carbon dioxide (CO2), and ammonia (NH3), in driving climate change and global warming by trapping heat within the Earth's atmosphere. This has ignited an escalating interest amongst researchers to devise sensor materials capable of efficiently detecting and monitoring these gases. Herein, a novel interface material composed of boron (B) and nickel (Ni) encapsulated within a graphene/PEDOT matrix (B_Ni@GP_PEDOT) was subjected to comprehensive simulations employing density functional theory (DFT) at the B3LYP-GD3(BJ)/Def2-SVP level of theory. The primary objective of these simulations was to assess the potential of B_Ni@GP_PEDOT in detecting and capturing targeted ruminant gases. The outcomes of molecular dynamics simulations unveiled a favourable interaction between B_Ni@GP_PEDOT and all three gases, with CO2 displaying the strongest attractive interaction. Interestingly, these simulations also revealed a substantial rise in system temperature during the interaction, indicative of significant energy transfer from the gases to the solid structure. Furthermore, an insightful evolution in the band gap of the system was observed, signifying increased stability. Specifically, the sequence B_Ni@GP_PEDOT_NH3 < B_Ni@GP_PEDOT_CH4 < B_Ni@GP_PEDOT < B_Ni@GP_PEDOT_CO2 was established, corresponding to ascending energies of 1.30 < 1.49 < 1.72 < 1.78 eV, respectively. Intriguingly, a comprehensive analysis of the mechanistic adsorption behaviour of the studied gases indicated varying degrees of energy for adsorption: B_Ni@GP_PEDOT_CH4 < B_Ni@GP_PEDOT_CO2 < B_Ni@GP_PEDOT_NH3, corresponding to energies of -0.273, -0.191, and -0.047 eV, respectively. The nature of the interaction between the adsorbent and adsorbates was meticulously explored using Quantum Theory of Atoms in Molecules (QTAIM) and Non-Covalent Interaction (NCI) analysis, yielding outcomes that perfectly aligned. Interestingly, B_Ni@GP_PEDOT_CO2 system was observed to have a more stable configuration with