QTAIM Analysis Research Articles

QTAIM analysis of the bonding in anionic group 6 carbonyl selenide clusters: [Se2M3(CO)10]2- (M=Cr, Mo, W).

This research aims to offer a deeper understanding of the bonding interactions between M-Se and M-CO and how these interactions change across the group 6 transition metal series: [Se2M3(CO)10]2- (M = Cr, Mo, W). It also seeks to explore the impact of carbonyl groups on M-M interactions within the clusters. Seven criteria, which are based on QTAIM properties, have been considered and compared with the corresponding criteria in other transition metal clusters. The results confirm that no such bond critical points or bond baths occur between transition metals, which instead have 5c-7e bonding interactions delocalized over their five-membered M3(μ-Se)2 ring, as evidenced by the non-negligible nonbonding delocalization indices. The topological properties of three bond clusters, Cr-Se, Mo-Se, and W-Se, resemble those of "intermediate closed shell characters," which combine covalent and electrostatic properties. Source function calculations indicated that the bonded Se atom contributed the most to each Cr-Se and Mo-Se bcp. The OCO atoms and nonbonded Se atoms also contributed to some extent. However, metal atoms act as sinks rather than as sources of electron density. In contrast, the majority of the metal atoms, both bonded and nonbonded, contribute to Cr-W bcps. Analysis of the delocalization indices δ(M…O) in the three clusters indicates that CO significantly contributes to Cr π-back donation in cluster 1. In contrast, no π-back donation occurs from CO to Mo or W in clusters 2 or 3, respectively. The B3P86 hybrid functional was used for computations in the Gaussian 09 software. The LanL2DZ basis set was employed for Cr, Mo, and W, while the 6-31G (d, p) basis set was used for C, O, and Se atoms. We performed QTAIM analysis using the AIM2000 and Multiwfn packages, incorporating B3P86/WTBS for Cr, Mo, and W atoms. The 6-311++G(3df,3pd) basis set was used for C, O, and Se atoms. Additionally, we utilized the ELF and SF.

DFT-Computational Modeling and TiberCAD Frameworks for Photovoltaic Performance Investigation of Copper-Based 2D Hybrid Perovskite Solar Absorbers.

In this work, we use a combination of dispersion-corrected density functional theory (DFT-D3) and the TiberCAD framework for the first time to investigate a newly designed and synthesized class of (C6H10N2)[CuCl4] 2D-type perovskite. The inter- and intra-atomic reorganization in the crystal packing and the type of interaction forming in the active area have been discussed via Hirshfeld surface (HS) analyses. A distinct charge transfer from CuCl4 to [C6H10N2] is identified by frontier molecular orbitals (FMOs) and density of states (DOS). This newly designed narrow-band gap small-molecule perovskite, with an energy gap (E g) of 2.11 eV, exhibits a higher fill factor (FF = 81.34%), leading to an open-circuit voltage (V oc) of 1.738 V and a power conversion efficiency (PCE) approaching ∼10.20%. The interaction between a donor (D) and an acceptor (A) results in a charge transfer complex (CT) through the formation of hydrogen bonds (Cl-H), as revealed by QTAIM analysis. These findings were further supported by 2D-LOL and 3D-ELF analyses by visualizing excess electrons surrounding the acceptor entity. Finally, we performed numerical simulations of solar cell structures using TiberCAD software.

Understanding Trimipraminium Maleate (TPM) through Spectroscopic, Hirshfeld surface and reactivity analysis: Experimental, DFT and MD studies in different solvents at different temperatures

The electrical and vibrational properties of Trimipraminium maleate (TPM) are reported experimentally and theoretically. Vibrational spectra were recorded, and theoretical wavenumbers were determined and assigned using potential energy distribution. The intra-molecular hydrogen bonding O–H⋯O interaction in maleate is reflected by Hirshfeld surfaces. A small energy gap explains a possible charge transfer via N–H⋯O intermolecular interaction. MD simulations studies were carried out for the TPM at varying temperatures 300, 310, 320, and 330K in three different solvents (water, DMSO, and methanol). Non-covalent interactions are implied from the QTAIM analysis.

Nanosheets adsorption and antiviral activity of Favipiravir drug against envelope proteins of yellow fever virus: DFT and molecular docking simulation study

Our previous research investigated the delivery of Favipiravir (FAV) drug through the encapsulation of FAV into 1D nanomaterials (NMs), AlN, BN, and carbon nanotubes, now we evaluated the possibility of using 2D NMs carbon nanosheets (GPNS), boron nitride nanosheets (BNNS), and aluminum nitride nanosheets (AlNNS) as drug delivery systems. The adsorption of FAV drug in its two tautomeric forms over the surfaces of these NSs is conducted. The adsorption energies are in the range of − 0.681 to − 2.469 eV. FAV binds to BNNS and GPNS through stacking interactions, while it chemisorbs to AlNNS. NCI and QTAIM analyses confirmed the dominance of vdW interactions. The recovery times over NSs were shorter than those inside NTs, and they indicated that NSs are better for drug release while NTs bind better and have larger adsorption energies. MD simulations revealed that FAV showed a good level of resistance to yellow fever virus (YFV) infections.

Syntheses and Conformations of a Trinuclear Gold(I) System Based on a Triethinyl‐trisilacyclohexane Scaffold

AbstractTrisilacyclohexanes and bissilylmethanes with acetylene units attached to silicon sites have been converted into tri‐ and di‐nuclear gold(I)phosphane complexes and characterized by NMR spectroscopy and X‐ray diffraction. The bissilylmethane‐based gold complexes were used as a test system to work out the synthetic routes before transferring them to the trisilacyclohexane scaffolds, because the latter are more difficult to access. The occurrence of aurophilic interactions (short Au ⋅ ⋅ ⋅ Au contacts) depends on the steric bulk of the phosphorus‐bonded alkyl and aryl groups. DFT studies show that dispersion effects play an important role in the ability to form intramolecular Au ⋅ ⋅ ⋅ Au interactions. QTAIM analyses show that a subtle change of the steric bulk of the phosphane groups alters the relative strength of the dispersion and aurophilic interactions. The combination of DFT studies and X‐ray diffraction experiments shows that the conformation of the trisilacyclohexane backbone is also phase dependent.

First principles study on interactions in inorganic molecular crystals at zero dimensions

Inorganic molecular crystals (IMCs) are attracting significant scientific interest due to their distinctive anisotropic crystal structure. The molecular units in the form of cages are the fundamental unit of these materials and most of their properties are dependent on the geometry, their arrangement and the interactions present in between these cages. This work is carried out to shed light on the structural arrangement and the interaction properties of three IMCs including antimony oxide (Sb2O3), phosphorous tri-selenium (P4Se3) and phosphorous trioxide (P4O6) in zero dimensions. The reported calculations were carried out using density Functional Theory (DFT) to investigate the interactions between the cages based on ETS-NOCV, NBO, Wiberg bond indices and QTAIM analysis. The results revealed weak VdWs association along the inter-cages and significant covalent bonding within the cage. The investigation shows that Sb2O3 and P4Se3 IMCs have potential applications in high-pressure and stress-bearing materials.

Hydrogen bonding, halogen bonding and C–H…π interactions governing the supramolecular architecture of 1-(4-(4-bromophenyl)piperazin-1-yl)-2-chloroethan-1-one: Insights from X-ray crystallography, DFT calculations and urease inhibitory assessment

The use of organic ligands for the generation of supramolecular architectures exhibiting interesting structural properties in crystal engineering have garnered significant attention. In this context, the current work highlights the use of 1-(4-(4-bromophenyl)piperazin-1-yl)-2-chloroethan-1-one (3) as a valuable synthon for evaluating the conspicuous role of several types of noncovalent interactions governing the formation of supramolecular assemblies. Compound 3 was successfully synthesized in good yield using a facile two-step approach and characterized through spectroscopic and X-ray crystallographic methods. Noncovalent interactions including C—H…O, C—H…Cl, C—H…π as well as C—Br…Cl halogen bonds were found as the key contacts in the crystal packing of compound 3. DFT calculations were employed to identify and assess the impact of the C—Br…Cl halogen bond, utilizing MEP, QTAIM, and NBO analyses. These studies confirmed that the Br atom acts as the halogen bond donor and the Cl atom as the halogen bond acceptor. Assessment of urease inhibitory efficacy revealed that the tested compound exhibits a 16-folds superior inhibition than thiourea. Computational modeling analysis augmented the in vitro results by exhibiting numerous favorable binding interactions between compound 3 and active site residues such as TYR32, LYS709, PHE712, ASP730, VAL744 and MET746. The pharmacokinetic evaluation classified the investigated piperazine derivative into a druggable compound.

Extraction of uranyl from spent nuclear fuel wastewater via complexation—a local vibrational mode study

ContextThe efficient extraction of uranyl from spent nuclear fuel wastewater for subsequent reprocessing and reuse is an essential effort toward minimization of long-lived radioactive waste. N-substituted amides and Schiff base ligands are propitious candidates, where extraction occurs via complexation with the uranyl moiety. In this study, we extensively probed chemical bonding in various uranyl complexes, utilizing the local vibrational modes theory alongside QTAIM and NBO analyses. We focused on (i) the assessment of the equatorial O-U and N-U bonding, including the question of chelation, and (ii) how the strength of the axial U=\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$=$$\\end{document}O bonds of the uranyl moiety changes upon complexation. Our results reveal that the strength of the equatorial uranium-ligand interactions correlates with their covalent character and with charge donation from O and N lone pairs into the vacant uranium orbitals. We also found an inverse relationship between the covalent character of the equatorial ligand bonds and the strength of the axial uranium-oxygen bond. In summary, our study provides valuable data for a strategic modulation of N-substituted amide and Schiff base ligands towards the maximization of uranyl extraction.MethodQuantum chemistry calculations were performed under the PBE0 level of theory, paired with the relativistic NESCau Hamiltonian, currently implemented in Cologne2020 (interfaced with Gaussian16). Wave functions were expanded in the cc-pwCVTZ-X2C basis set for uranium and Dunning’s cc-pVTZ for the remaining atoms. For the bonding properties, we utilized the package LModeA in the local modes analyses, AIMALL in the QTAIM calculations, and NBO 7.0 for the NBO analyses.Graphical abstract

Influence of the steric bulk of a trityl group in the formation of molecular metallosilicates

The molecular silanol (Ph3CO)(iPrO)2Si(OH) was designed to evaluate the degree of steric bulk the trityl moiety imposes on the Si–OH group. The reactivity of the silanol was evaluated by the formation of three metallosilicates with lithium, aluminum, and gallium, and their molecular structures and the degree of association were determined. Hirshfeld atom refinement or DFT calculation, and QTAIM analysis of the electron density in all compounds were used to analyze the bonding situation in the metallosilicate moieties and determine the strength of the intermolecular hydrogen bonds formed by the silanol. Finally, ring-opening polymerization of ε-caprolactone was used as another criterion for the evaluation of the steric bulk imposed by the trityl group.

Ternary Complexes of BiI3/CuI and SbI3/CuI with Tetrahydrothiophene.

Reactions of BiI3/CuI mixtures with tetrahydrothiophene (THT) in toluene produce 2-D sheet networks BiCu3I6(THT)n (n = 2, 3, or 4), depending on reaction conditions. All three structures are based on BiI6 octahedra, which share pairs of (μ2-I)2 with Cu3(THT)n units. BiCu3I6(THT)2 features Cu2(μ2-I)2 rhombs with close Cu···Cu interactions and is accompanied by formation of the very complex HBi3Cu12I22(THT)8. Reactions of SbI3/CuI with THT in toluene produced a SbCu3I6(THT)2 network shows Cu3(μ2-THT)2 units, like its Bi congener, but Cu6(μ2-I)6 barrels rather than rhombs. Isolated SbI3 units are stacked above the Cu6I6 barrels. A molecular compound, Sb3Cu3I12(THT)6 consists of a face-sharing Sb3I12 stack, in which the Cu-THT units are bonded in asymmetric fashion about the central SbI6. Metal-halide bonds were investigated via QTAIM and NLMO analyses, demonstrating that these bonds are largely ionic and occur between the Bi/Sb and I p orbitals. Hirshfeld analysis shows significant H···H and H···I interactions. Diffuse reflectance spectroscopy (DRS) reveals band edges for the Bi species of 1.71-1.82 eV, while those for the neutral Sb complexes are in the range of 1.94-2.06 eV. Mapping of the electronic structure via density of state calculations indicates population of antibonding Bi/Sb-I orbitals in the excited state.

Synthesis and X-ray characterization of two new 1,4-benzoxazine derivatives: Structural analysis and DFT calculations

The synthesis and XRD characterization of two new 1,4-benzoxazine derivatives (3a-5a) namely ethyl‐6‐nitro‐3a‐(p‐tolylamino)‐1,2,3,3a‐tetrahydrobenzo[b]cyclopenta[e][1,4]oxa-zine‐9a(9H)‐carboxylate (3a) and methyl-6,10b-dimethyl-5a,6,10b,11-tetrahydrobenzo[5,6][1,4]oxazino[2,3-b]indole-2-carboxylate (5a) are reported herein. In both compounds it is observed the formation of π···π and CH···π interactions and strong NH···O H-bonds, which were studied energetically at the PBE0-D3/def2-TZVP level of theory. The Hisrhfeld surface and QTAIM analyses and NCI plots were used to study the nature and the extent of different intermolecular interactions observed in both structures, revealing the existence of additional R21(6) and R21(7) synthons. In addition, using the potential energy density as energy predictor, the QTAIM method is useful to investigate the relative contribution of each interaction to the formation of the assemblies.

A Comparative DFT Investigation of the Adsorption of Temozolomide Anticancer Drug over Beryllium Oxide and Boron Nitride Nanocarriers.

Herein, attempts were made to explore the adsorption prospective of beryllium oxide (Be12O12) and boron nitride (B12N12) nanocarriers toward the temozolomide (TMZ) anticancer drug. A systematic investigation of the TMZ adsorption over nanocarriers was performed by using quantum chemical density functional theory (DFT). The favorability of Be12O12 and B12N12 nanocarriers toward loading TMZ was investigated through A↔D configurations. Substantial energetic features of the proposed configurations were confirmed by negative adsorption (E ads) energy values of up to -30.47 and -26.94 kcal/mol for TMZ•••Be12O12 and •••B12N12 complexes within configuration A, respectively. As per SAPT results, the dominant contribution beyond the studied adsorptions was found for the electrostatic forces (E elst = -100.21 and -63.60 kcal/mol for TMZ•••B12N12 and •••Be12O12 complexes within configuration A, respectively). As a result of TMZ adsorption, changes in the energy of molecular orbitals followed by alterations in global reactivity descriptors were observed. Various intermolecular interactions within the studied complexes were assessed by QTAIM analysis. Notably, a favorable adsorption process was also observed under the effect of water with adsorption energy ( reaching -28.05 and -22.26 kcal/mol for TMZ•••B12N12 and •••Be12O12 complexes within configuration A, respectively. The drug adsorption efficiency of the studied nanocarriers was further examined by analyzing the IR and Raman spectra. From a sustained drug delivery point of view, the release pattern of TMZ from the nanocarrier surface was investigated by recovery time calculations. Additionally, the significant role of doping by heavy atoms (i.e., MgBe11O12 and AlB11N12) on the favorability of TMZ adsorption was investigated and compared to pure analogs (i.e., Be12O12 and B12N12). The obtained data from thermodynamic calculations highlighted that the adsorption process over pure and doped nanocarriers was spontaneous and exothermic. The emerging findings provide a theoretical base for future works related to nanocarrier applications in the drug delivery process, especially for the TMZ anticancer drug.

Interplay of weak noncovalent interactions in (E)-4-chloro-N’-(thiophen-2-ylmethylene)benzohydrazide: Insights from Hirshfeld surface, PIXEL energy and QTAIM analyses

A newly synthesized compound, (E)-4-chloro-N'-(thiophen-2-ylmethylene)benzohydrazide, has undergone characterization through NMR and single crystal X-ray diffraction techniques. By leveraging the Cambridge Structural Database (CSD), closely related structures to the title compound were identified and compared in terms of conformation to elucidate the substitution effect. Furthermore, Hirshfeld surface analysis and the assessment of the relative contribution of various intermolecular interactions shed light on the impact of substitutions introduced in hydrazide derivatives. The energetics of the molecular dimers observed in the title compound were delineated using CLP-PIXEL energy calculations. These dimers are formed from a range of non-covalent interactions, including a strong N–H⋅⋅⋅O=C hydrogen bond, N–H⋅⋅⋅N, and C–H⋅⋅⋅N/OS/π interactions. Moreover, a σ-hole interaction, such as a chalcogen bond, is observed in one of the molecular dimers, coexisting with other types of interactions to stabilize the molecular dimer. The nature of the chalcogen bond was characterized through a deformation electron density map. The dimensionality of the similarity between the title compound and its closely related structures from the CSD was calculated to comprehend the effect of substitution introduced in one of the aryl rings in hydrazide derivatives. Furthermore, topological analysis was conducted to examine the nature and strength of noncovalent interactions present in the title compound using the framework of the quantum theory of atoms in molecule (QTAIM).

Structural Diversity and Rare η1 Cu-C Interactions in CuI Complexes of 1,2,3-Triazole-Functionalized Bisphosphines.

This manuscript describes the synthesis of copper complexes of 1,2,3-triazolyl-phosphines: o-Ph2P(C6H4){1,2,3-N3CC6H5)C(PPh2)} (L1), (C6H5){1,2,3-N3C(C6H4(o-PPh2))-C(PPh2)} (L2), 3-Ph2P(C5H3N){1,2,3-N3C(C6H5)C(PPh2)} (L3), o-Ph2P(C6H4){1,2,3-N3C(C5H5N)C(PPh2)} (L4), and {(3,5-Ph2PC6H4-o)21,2,3-N3CCH} (L5). The reactions of L1-L3 with CuI salts afforded dimeric complexes having the general formula [Cu2(μ -X)2L2] (L = L1, X = Cl, Br and I: 1 - 3; L= L2, X = Cl, Br and I: 4- 6; L = L3; X = Cl, Br, and I: 7-9). The reaction of L4 with CuI in a 1:2 molar ratio afforded 1D-coordination polymer [{(CuI)2{o-Ph2P(C6H4){1,2,3-N3C(C5H5N)C(PPh2)}-μ-((k1-N)(k2-P,P))}}]n (10). The reaction of L5 with cuprous halides (CuX) (X = Br, I) yielded mononuclear complexes [CuX{(3,5-Ph2PC6H4-o)21,2,3-N3CCH}-κ2P,P] (X = Br, 12; I, 13). Crystal structures of complexes 12 and 13 showed close interactions between CuI and the triazole C7 carbon. These relatively short Cu···C7 separations may be due to the η1-C interaction (dπ-pπ bond) between the triazolic carbon atom (via pz orbital) and CuI or three-centered two-electron interaction between CuI and the triazolic C-H bond. The existence of the Cu···C interaction was further evinced by the QTAIM analysis in compounds 12 and 13.

Exploring the bonding and extraction separation effects of N donor ligands with different skeletons on Am(III) and Eu(III)

Designing ligands for effective separation of actinide(III)/lanthanide(III) is one of the key issues in the treatment of spent nuclear fuel. However, due to the chemical similarity of trivalent actinides and lanthanides, their separation faces a great challenge in the reprocessing of spent nuclear fuel. Nitrogen donor extractants are considered as promising reagents for separation of trivalent actinides and lanthanides. To the best of our knowledge, the pre-organized structure of the ligand has a strong influence on the extraction separation capacity. In this work, we designed four N-donor ligands (L1 and L2 with pyridine and bipyridine skeletons, respectively, and L3 and L4 both with phenanthroline skeletons) with different pre-organized structures and investigated their selective extraction for Am(III) and Eu(III) by using scalar relativistic density functional theory (DFT). The absolute minimum ESP values of these ligands and the higher HOMO level suggest that the ligand L2 may have a stronger affinity for Am(III)/Eu(III) ions than other ligands. The three average bond lengths of each complex indicate that the Am(III) and Eu(III) ions have larger bond lengths with N2 atoms than with N1 atoms. Various theoretical approaches have been used to evaluate the properties of the four ligands as well as the coordination structures, bonding properties and thermodynamic properties of the complexes of the four ligands with Am(III) and Eu(III). The WBIs, QTAIM, NBO, DOS and EDA analysis indicate that the metal–ligand bonds are mainly ionic in character, the Am-N bond has more covalency than the Eu-N bond because the Am 5f orbitals are more involved in bonding with ligand than Eu 4f orbitals. According to the extended transition state and natural orbital chemical valence theory (ETS-NOCV) analysis, electrons are obviously transferred from the lone pair of the ligand N atom to the hybrid s, d and f orbitals of the metal ion. The thermodynamic results show that the four ligands can coordinate well with the Am and Eu ions, and also have suitable separation capacity for Am and Eu. Among the four ligands, the L2 and L3 ligands have the strongest coordination ability for metals and the best extraction separation effect for Am and Eu. It can be seen that the bridging skeleton of the ligand and the number of N atoms on the five-membered ring and also different organic solvents have obvious effects on the extraction and separation capacity of the ligand. This study provides a theoretical basis for the efficient separation of Am(III)/Eu(III) by adjusting the preorganization level of ligands, and provides a theoretical basis for the design and screening of ligands by preorganization.

Synthesis, Structural Characterisation, and Electrochemical Properties of Copper(II) Complexes with Functionalized Thiosemicarbazones Derived from 5-Acetylbarbituric Acid.

The reaction between 5-acetylbarbituric acid and 4-dimethylthiosemicarbazide or 4-hexamethyleneiminyl thiosemicarbazide produces 5-acetylbarbituric-4-dimethylthiosemicarbazone (H2AcbDM) and 5-acetylbarbituric-4N-hexamethyleneiminyl thiosemicarbazone (H2Acbhexim). Eight new complexes with different copper(II) salts have been prepared and characterized using elemental analysis, molar conductance, UV-Vis, ESI-HRMS, FT-IR, magnetic moment, EPR, and cyclic voltammetry. In addition, three-dimensional molecular structures of [Cu(HAcbDM)(H2O)2](NO3)·H2O (3a), [Cu(HAcbDM)(H2O)2]ClO4 (4), and [Cu(HAcbHexim)Cl] (6) were determined by single crystal X-ray crystallography, and an analysis of their supramolecular structure was carried out. The H-bonded assemblies were further studied energetically using DFT calculations and MEP surface and QTAIM analyses. In these complexes, the thiosemicarbazone coordinates to the metal ion in an ONS-tridentate manner, in the O-enolate/S-thione form. The electrochemical behavior of the thiosemicarbazones and their copper(II) complexes has been investigated at room temperature using the cyclic voltammetry technique in DMFA. The Cu(II)/Cu(I) redox system was found to be consistent with the quasi-reversible diffusion-controlled process.

Combined DFT and ionic model computational study of the effect of alkali metal cations on the structure, bonding and properties of molten cryolites, M3AlF6 (M = li, Na, K, Rb, and Cs)

ABSTRACT Ionic melts, in the form of ionic liquids and molten salts, are important in many technological aspects such as metal production and energy applications. Cryolite melts constitute an important family especially for the industrial production of Al. The present computational study aims to analyse the effect of different cations on the structure and properties of Al (III) fluorocomplexes in cryolite melts. Cation effects are discussed as the ion pair interactions due to alkali metal cations of cryolite compounds M3AlF6 with M= Li, Na, K, Rb, or Cs for various microclusters using ionic interaction model (IM) and DFT calculations. DFT results for different ion complexes are compared with the energy calculations using a pseudoclassical model for isolated clusters. QTAIM and ELF analyses were performed to understand the nature of interactions in detail. A link between open-shell interactions and decreased ionic conductivity is proposed within the series of K, Rb, and Cs. Environmental effects, such as temperature and presence of other ions, are investigated in detail by DFT analysis.

Noncovalent and Covalent O-H···O Interactions in PPh3O Cocrystals: A Correlation Study Involving QTAIM, SAPT, NBO, and IBSI Methods.

PPh3O.hemihydrate polymorphs and 11 assorted PPh3O cocrystals collectively constitute a reliable stock to pursue a systematic analysis aiming to investigate the impacts of some vital issues on the TPPO.H-bond donor aggregates. The issues highlighted herein are (i) effect of varying acidity of H-bond donors on the degeneracy of lone pairs of the H-bond acceptor (PPh3O), (ii) effectiveness of the |V(r)|/G(r) and H(r)/ρ(r) parameters as a covalency metric, (iii) 3c-4e bonding in the covalent PPh3O.nitric acid cocrystal, (iv) salient features of H-bond interaction energy and an interplay of its components, (v) an intrinsic bond strength scale for the PPh3O cocrystals, and (vi) reliable empirical relations between several bond descriptors for a quick estimation of interaction energy. To be specific about point (vi), we have propounded two promising avenues for a fast semiquantitative calculation of interaction energy from an endearing nonenergetic parameter, viz., bond length: dO-H···O → ρBCP (MAPE = 2.36%) → ESAPT0 (MAPE = 9.26%), and dO-H···O → IBSI (MAPE = 1.87%) → ESAPT0 (MAPE = 9.66%). All the aforesaid issues have been explored in detail through the QTAIM, NBO, and IBSI analyses (M06-2X-D3/def2-TZVP level), as well as by the SAPT study at the SAPT0/aug-cc-pVDZ platform. The statistically valid correlation studies can be particularly conducive for practical purposes as a transformative extension of the established facts into postulates for the unknown cocrystals.

Exploring the Efficiency of Algerian Kaolinite Clay in the Adsorption of Cr(III) from Aqueous Solutions: Experimental and Computational Insights.

The current study comprehensively investigates the adsorption behavior of chromium (Cr(III)) in wastewater using Algerian kaolinite clay. The structural and textural properties of the kaolinite clay are extensively characterized through a range of analytical methods, including XRD, FTIR, SEM-EDS, XPS, laser granulometry, N2 adsorption isotherm, and TGA-DTA. The point of zero charge and zeta potential are also assessed. Chromium adsorption reached equilibrium within five minutes, achieving a maximum removal rate of 99% at pH 5. Adsorption equilibrium is modeled using the Langmuir, Freundlich, Temkin, Elovich, and Dubinin-Radushkevitch equations, with the Langmuir isotherm accurately describing the adsorption process and yielding a maximum adsorption capacity of 8.422 mg/g for Cr(III). Thermodynamic parameters suggest the spontaneous and endothermic nature of Cr(III) sorption, with an activation energy of 26.665 kJ/mol, indicating the importance of diffusion in the sorption process. Furthermore, advanced DFT computations, including COSMO-RS, molecular orbitals, IGM, RDG, and QTAIM analyses, are conducted to elucidate the nature of adsorption, revealing strong binding interactions between Cr(III) ions and the kaolinite surface. The integration of theoretical and experimental data not only enhances the understanding of Cr(III) removal using kaolinite but also demonstrates the effectiveness of this clay adsorbent for wastewater treatment. Furthermore, this study highlights the synergistic application of empirical research and computational modeling in elucidating complex adsorption processes.

DFT investigation on the application of a thiol-protected gold cluster Au12(SCH3)9+ toward adsorption of temozolomide

The adsorption behavior of a thiol-protected gold cluster Au12(SCH3)9+ to temozolomide (TMZ) has been investigated at the M06-2X-D3/6-311G(d, p)&LanL2dz//B3LYP-D3(BJ)/6-31G(d,p)&LanL2dz. Results show that TMZ prefers to combine with the central Au atom in the Au cluster via its O and N atoms, forming ionic Au–O and Au–N bonds, respectively. The calculated adsorption energies of TMZ on Au12(SCH3)9+ are − 44.43, −12.27, −43.59, and −10.01 kcal·mol−1 in the gas phase, water, acetic acid, and dimethyl sulfoxide, respectively. The interaction strength and mode between the TMZ drug and Au12(SCH3)9+ vary with different solution environments. Therefore, the solvent could influence the interaction of TMZ-Au12(SCH3)9+ complexes. Such a property of TMZ–Au12(SCH3)9+ could be applied to drug-delivery processes, which might contribute to improving the efficiency of this drug and reducing its toxic and side effects. Based on the natural population analysis and QTAIM analysis, noticeable charge transfer from TMZ to the Au cluster was observed, increasing the dipole moments of TMZ–Au12(SCH3)9+ complexes. We believe that this work could extend the applications of small Au-based clusters, especially thiol-protected gold clusters in drug-delivery processes.