Quantum Theory Of Atoms In Molecules Research Articles

Exploring boron nitride nanostructures for effective pyrazinamide drug delivery: A DFT study

In present investigation, interactions of pyrazinamide molecule with boron nitride nanocones (BNC), boron nitride nanosheet (BNS), and boron nitride nanotube (BNT) as nanostructures have been studied for drug delivery applications via DFT computations. For DFT computations on studied models, two phases (aqueous and gaseous) have been regarded. In both phases, a stabilized complex of nanostructures and pyrazinamide has been obtained based on adsorption energy (Eads) values. According to negative Eads value, an exothermic reaction has been observed. The hydrogen bonding has found in all complexes due to low and positive values of electron density in critical points of bond (ρr) based on the quantum theory of atoms in molecules (QTAIM). Computations outcomes also revealed that there were weak interaction forces for successful and significant unloading of curcumin from carriers in target sites. In order to assess impact of molecular adsorption over electronic features of nanostructures, density of states (DOS) has been analyzed, and outcomes indicated that BNC was more proximate to Fermi energy compared to other nanomaterials. In gaseous phase, Eads values were greater than aqueous phase, which indicates a more robust interaction of molecules with nanostructures. Compared to other nanostructures, curcumin had stronger interaction with BNC based on Eads values. At the end of pyrazinamide adsorption, ΔEg values were – 1.17, − 0.27, and −0.19 eV for BNC, BNS, and BNT, respectively, which reveal that BNC had more sensitivity than BNS and BNT. Based on computations conducted in present work, nanostructures could potentially be employed to deliver pyrazinamide.

Unraveling non-covalent interactions in bis-chalcone: A crystallographic and theoretical studies

A new bis-chalcone THXA, (2E,2′E)-1,1′-(((1,4-phenylenebis(methylene))bis(oxy))bis(2,1-phenylene))bis(3-(thiophen-2-yl)prop‑2-en-1-one) is synthesized and characterized by spectroscopic and single crystal X-ray diffraction techniques from chalcone (E)-1-(2-hydroxyphenyl)-3-(thiophen-2-yl)prop‑2-en-1-one) and xylene dibromide. The intermolecular non-covalent interactions such as π···π, CH···S and CH···π participate decisive roles in the development of supramolecular structures. An inclusive Hirshfeld surface analysis discloses the presence of intermolecular non-covalent interactions. The 2D fingerprint plots reveal individual atom's percentage contributions in construction of the non-covalent interactions. Hirshfeld energy framework study affirms dominance of the dispersive π-π interaction in THXA. Further, energetic estimation for non-covalent interactions of dimeric unit has been calculated through density functional theory (DFT). The molecular electrostatic potential (MEP) surfaces help to describe the charge distribution in THXA. Additionally, the non-covalent interactions in THXA are also examined by computational tools like non-covalent interaction (NCI) plot index and quantum theory of atoms in molecules (QTAIM) analysis.

Structures of DMSO clusters and quantum cluster equilibrium (QCE)

Dimethylsulfoxide (DMSO) clusters are crucial for understanding processes in liquid DMSO. Despite its importance, DMSO clusters have received negligible attention due to the complexity of their potential energy surfaces (PESs). In this work, we explored the PESs of the DMSO clusters from dimer to decamer, starting with classical molecular dynamics, followed by full optimizations at the PW6B95-D3/def2-TZVP level of theory. In addition, the binding energies, the binding enthalpy per DMSO, and the quantum theory of atoms in molecules (QTAIM) analysis of the most stable isomers are reported. Temperature effects on the stability of the isomers have also been assessed. After thoroughly exploring the PESs of the DMSO clusters, 159 configurations have been used to apply the quantum cluster equilibrium (QCE) theory to liquid DMSO. The quantum cluster equilibrium theory has been applied to determine the liquid properties of DMSO from DMSO clusters. Thus, using the QCE, the population of the liquid DMSO, its infrared spectrum, and some thermodynamic properties of the liquid DMSO are predicted. The QCE results show that the population of the liquid DMSO is mainly dominated by the DMSO dimer and decamer, with the contribution in trace of the DMSO monomer, trimer, tetramer, pentamer, and octamer. More interestingly, the predicted infrared spectrum of liquid DMSO is in qualitative agreement with the experiment.

Cooperativity and topological hydrogen bonding in aromatic diol complexes

AbstractComplexes of three aromatic diols, catechol, naphthalene‐1,8‐diol, and fluorene‐4,5‐diol, with a series of hydrogen bond acceptors (HBAs) that have oxygen, nitrogen, and sulfur acceptor atoms, have been studied by density functional theory (DFT) at the B3LYP/6‐311+G(d,p) level. Binding energies, geometries, infrared spectroscopic (IR) frequencies, nuclear magnetic resonance (NMR) shifts, and measures of the electron density distribution from the Quantum Theory of Atoms in Molecules (QTAIM) are evaluated and compared with data for the corresponding monohydroxy compounds (monols), phenol, naphth‐1‐ol, and fluorene‐4‐ol, in order to assess the importance of cooperativity between intramolecular and intermolecular hydrogen bonding. All measures for all complexes show positive cooperativity whereby both the intermolecular and intramolecular hydrogen bonds are strengthened upon complexation. Cooperativity is weak for catechol and strong for the other two diols and, for all diols, increases with the hydrogen bond basicity of the acceptor. Correlations of IR and NMR metrics against binding energies for a single HBA and all six monols and diols are excellent, but attempts to correlate the same metrics for all HBAs and a single donor are frustrated by differences in intermolecular hydrogen bonding, depending notably on the identity of the acceptor atom in the HBA. Atom–atom interaction energies, calculated by the Interacting Quantum Atoms approach, are used to discuss the covalency of both types of hydrogen bond.

Halogen Bonding in Brominated BODIPY Crystals: a Crystallographic and Computational Study.

The study of halogen bonds (XBs) has been a subject of great interest in recent years due to its clear application in catalysis, liquid crystals, and crystal engineering. In this study we analyzed the intermolecular interactions, in particular halogen bonds in BODIPYs with increasing number of bromine atoms. The computational study included analyses through three different methods: the first approach of close contacts provided by Mercury, then the expanded approach of the electron density partition of the molecules in the crystals provided by the analysis of Hirshfeld surfaces, and finally, the approach of the Quantum Theory of Atoms in Molecules (QT-AIM) to characterize the non-covalent interactions through finding electron density critical points between atoms and between neighboring molecules. The use of different computational methods allowed to gain insight on the interactions directing the crystal packing as the number of bromine atoms increase in the BODIPY moiety. Monocoordinated and bifurcated halogen bonds involving halide/halide were found. The penta-brominated BODIPY showed four-center cyclic nodes where each node is linked via XBs. This kind of motifs can be useful in supramolecular chemistry and self-assembly.

Optoelectronic Characterisation and Theoretical Insight into the Binding Mechanism of D‐π‐A Triphenylamine‐Organic Dyes for Dye Sensitized Solar Cells

AbstractThere has been a notable surge of interest in the field of dye sensitized solar cells (DSSCs) in recent years due to their remarkable performance in indoor/ambient and diffused light conditions. A significant portion of these highly efficient indoor DSSCs employs organic dyes based on triphenylamine. In this study, we present the findings of our investigation on two metal‐free D‐π‐A organic dyes, namely triphenylamine (YK 10) and hexyloxy‐substituted triphenylamine (YK 11), serving as electron donors. These dyes feature a 3,3′′‐dioctyl‐2,2′:5′,2′′‐terthiophene π‐spacer and cyanoacetic acid as the anchoring group. In order to comprehensively assess the relationship between the molecular structure, physical properties, and solar cell performance, we conducted in‐depth analysis involving photophysical, electrochemical, and theoretical studies. Our results indicate that these dyes possess the ability to effectively capture light within the visible spectrum and exhibit suitable energetic characteristics for efficient electron injection and dye regeneration. Through the utilization of density functional theory (DFT) modeling, we explored the interfacial adsorption configuration of the dyes on the TiO2 semiconductor, revealing the involvement of the cyano group in the anchoring mechanism for both sensitizers. Moreover, the intramolecular S…CN interaction in these dyes was verified through topological quantum‐theory‐of‐atom‐in‐molecule (QTAIM) analysis, which facilitates additional intramolecular charge transfer pathways. The DSSCs incorporating YK 10 and YK 11 demonstrated power conversion efficiencies (PCEs) of 6.42 % and 6.22 %, respectively, under full sun illumination (100 mW/cm2). Remarkably, under both standard 1000 lux CFL and LED illumination conditions, YK 11 exhibited superior performance with PCEs of 8.29 % and 5.89 %, respectively, surpassing the efficiencies of YK 10, which achieved 7.50 % and 5.09 % efficiencies under the same conditions.

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.

Molecular insight into endosulfan degradation by Ese protein from Arthrobacter: Evidence-based structural bioinformatics and quantum mechanical calculations.

Endosulfan is an organochlorine insecticide widely used for agricultural pest control. Many nations worldwide have restricted or completely banned it due to its extreme toxicity to fish and aquatic invertebrates. Arthrobacter sp. strain KW has the ability to degrade α, β endosulfan and its intermediate metabolite endosulfate; this degradation is associated with Ese protein, a two-component flavin-dependent monooxygenase (TC-FDM). Employing in silico tools, we obtained the 3D model of Ese protein, and our results suggest that it belongs to the Luciferase Like Monooxygenase family (LLM). Docking studies showed that the residues V59, V315, D316, and T335 interact with α-endosulfan. The residues: V59, T60, V315, D316, and T335 are implicated in the interacting site with β-endosulfan, and the residues: H17, V315, D316, T335, N364, and Q363 participate in the interaction with endosulfate. Topological analysis of the electron density by means of the Quantum Theory of Atoms in Molecules (QTAIM) and the Non-Covalent Interaction (NCI) index reveals that the Ese-ligands complexes are formed mainly by dispersive forces, where Cl atoms have a predominant role. As Ese is a monooxygenase member, we predict the homodimer formation. However, enzymatic studies must be developed to investigate the Ese protein's enzymatic and catalytic activity.

Strukturen, Bindungsanalyse und Reaktivität eines dikationischen Digallens und eines Diindens, die trans‐gefaltete Ditetrylene nachahmen

AbstractDie Reaktion von Bisdicyclohexylphosphinoethan (dcpe) und den subvalenten MI‐Quellen [MI(PhF)2][pf] (M=Ga+, In+; [pf] −=[Al(ORF)4]−; RF=C(CF3)3) ergab die Salze [{M(dcpe)}2][pf]2, die die ersten bisher dokumentierten dikationischen, trans‐gefalteten Digallen‐ und Diindenstrukturen enthalten. Die nicht‐klassischen MI⇆MI‐Doppelbindungen sind überraschend kurz und zeigen eine ditetrylenartige Struktur. Die Bindungssituation wurde durch quantenchemische Berechnungen, QTAIM‐ (Quantum Theory of Atoms in Molecules) und EDA‐NOCV‐Analysen (Energy Decomposition Analysis with the combination of Natural Orbitals for Chemical Valence) umfassend analysiert und mit derjenigen in den isoelektronischen und isostrukturellen, aber neutralen Digermenen und Distannenen verglichen. Das gelöste [{Ga(dcpe)}2]2+([pf]−)2 reagiert unter milden Bedingungen bei Raumtemperatur mit 1‐Hexen, Cyclooctin, Diphenyldisulfid und Diphenylphosphan. Diese Reaktivität wird analysiert und rationalisiert.

Structures, Bonding Analyses and Reactivity of a Dicationic Digallene and Diindene Mimicking trans-bent Ditetrylenes.

The reaction of bisdicyclohexylphosphinoethane (dcpe) and the subvalent MI sources [MI (PhF)2 ][pf] (M=Ga+ , In+ ; [pf]- =[Al(ORF )4 ]- ; RF =C(CF3 )3 ) yielded the salts [{M(dcpe)}2 ][pf]2 , containing the first dicationic, trans-bent digallene and diindene structures reported so far. The non-classical MI ⇆MI double bonds are surprisingly short and display a ditetrylene-like structure. The bonding situation was extensively analyzed by quantum chemical calculations, QTAIM (Quantum Theory of Atoms in Molecules) and EDA-NOCV (Energy Decomposition Analysis with the combination of Natural Orbitals for Chemical Valence) analyses and is compared to that in the isoelectronic and isostructural, but neutral digermenes and distannenes. The dissolved [{Ga(dcpe)}2 ]2+ ([pf]- )2 readily reacts with 1-hexene, cyclooctyne, diphenyldisulfide, diphenylphosphine and under mild conditions at room temperature. This reactivity is analyzed and rationalized.

Comparative analysis of interaction of ionic liquids with porous and non-porous electrode materials

Fascinating properties of ionic liquids such as their higher ionic conductivity, lower vapor pressure, high thermal and electrochemical stability, make them promising candidates as electrolytes for novel energy storage devices. Interaction of ionic liquids (ILs) as electrolytes with electrode is crucial for optimizing the efficiency of energy storage devices. Herein, we report the interaction mechanism of ionic liquids 1-3 dimethylimidazolium halide (1,3-DMIX) on porous covalent triazine frameworks (CTF-0) and non-porous carbon nitride (C4N) electrode materials. Molecular electrostatic potential (MEP) analysis is performed for the prediction of interacting sites on studied electrolytes and electrode materials. Significant changes in geometric and electronic parameters are observed upon interaction of ionic liquid electrolytes with C4N and CTF-0. The nature of interaction between ionic liquids and electrode surfaces is evaluated through Quantum theory of atoms in molecules (QTAIM) and non-covalent index (NCI) analyses which reveal that there exist only the non-covalent interactions (van der Waals) between them. Frontier molecular orbitals (FMO) analysis shows a significant decrease in energy gap upon interaction of ILs with CTF-0, which results in increase in electrical conductivity. Overall, porous CTF-0 electrode material displays greater interaction with the considered ILs as compared to non-porous C4N electrode material. This study will provide a way for experimentalist to explore ionic liquids and carbon nitride or covalent triazine framework as electrolyte–electrode systems which can be used further in energy storage devices like fuel cells, solar cells, ion batteries, and supercapacitors.

Computational Investigation of the Intermolecular Interactions between Decatungstate Acid and CX2O (X=H, F, Cl, and Br)

AbstractThis study explores intermolecular interactions between the polyoxometalate (POM) compound, decatungstate acid, and CX2O (X=H, F, Cl, and Br). Initial optimizations were conducted using the PBE0 and M06‐2X /Lanl2DZ level of theory, renowned for adsorption studies. Computational results revealed a notable sequential increase in binding affinity for reactive compounds on POM surfaces optimized with PBE0, TPSSH, M06‐2X, CAM‐B3LYP, and ωB97XD/Lanl2Dz methods. Interestingly, the findings indicated a high binding affinity between reactive compounds and POM surfaces, affirming M06‐2X functional suitability for studying decatungstate acid interactions. Additionally, adsorption energy (Eads) values were negative, indicating stable adsorption processes. Careful examination of quantum theory of atoms in molecules (QTAIM), natural charge calculations, and hybridization calculations unveiled impressive intermolecular interactions, with non‐covalent interactions (NCIs) revealing deep blue iso‐surfaces in (CH2O@POM) and (CF2O@POM) complexes, indicating significant electrostatic force of interaction and presence of hydrogen bond interactions, enhancing POM surface‘s gas interaction capacity and smooth sensing. The analyzed complexes displayed slight increases in HOMO‐LUMO energy gap compared to POM, with the order of increase as follows: CH2O@POM (0.0819 eV)>CF2O@POM (0.0772 eV)>CBr2O@POM (0.0747 eV)>CCl2O@POM (0.0705 eV), suggesting POM′s suitability as an adsorbent. The study‘s major findings reveal the effective adsorption of CBr2O and CH2O facilitated by hydrogen bond interactions on the POM surface, making decatungstate acid a potential adsorbent for removing polluting gases from the atmosphere.

Insights into different toxic molecular gases on the Fe-dimer anchored at C2N monolayer as potential sorbents and gas sensors: A theoretical approach

The fundamental aspects, including geometric structure, adsorption energy, thermodynamic properties, charge transfer, and magnetic properties of carbon nitride C2N and double-atom catalyst (Fe2@C2N) monolayers with the adsorption of CO, NO, HCN, CS2, and SO2 molecules, were investigated using DFT and DFT-D3 correction dispersion methods. Compared to pristine C2N, the Fe2@C2N monolayer is more energetically efficient with high adsorption energies and has apparent charge transfer with these toxic gases. Our results revealed that NO preferred to be adsorbed on the Fe2@C2N with a superior Eads of −7.006 eV. The electric conductivity, sensitivity, and selectivity of C2N are significantly influenced by CO, NO, HCN, CS2, and SO2 molecules. Moreover, the opening of band gaps induced by the adsorption of NO gas molecules at Fe2@C2N can be used as an electronic signal to detect NO gas. Intriguingly, the partial density of states (PDOS) indicated that the NO adsorption of pristine C2N and Fe2@C2N monolayers exhibited half-metallicity behavior and magnetic properties. Non-covalent interactions (NCI) and the quantum theory of atoms in molecules (QTAIM) descriptors were examined to analyze the interaction process. This study can provide a new avenue for synthesizing and developing highly sensitive candidates and inexpensive green double-atom catalysts to capture and detect CO, NO, HCN, CS2, and SO2 molecules from the atmosphere at ambient temperature.

Helical model of compression and thermal expansion

A negative linear temperature expansion and a negative linear compressibility were observed for imidazolium benzoate salt. Its strongly anisotropic strain induced by the temperature and pressure changes has been explained by the mechanism of H-bonded helices deformed in the structure. X-ray diffraction and vibrational spectroscopy were used to analyze interactions in the crystal. The Quantum Theory of Atoms in Molecules (QTAiM) approach was applied to analyze the hydrogen bonds and other interactions. In the salt under study, the interactions within the helix are substantially higher in energy than between helices. With decreasing temperature and increasing pressure, the value of the helix pitch increases while the value of the semi-major axis decreases, which results in the negative linear expansion and negative linear compression, respectively.

Highlighting non-covalent interactions to molecular structure, electronic and vibrational spectra in a new hybrid organic-inorganic cobalt complex: synthesis, experimental and computational study

Abstract In this study, a novel hybrid organic-inorganic compound, 4-(ammoniummethyl)pyridinium tetracholoraobaltate(II) monohydrate, with non-centrosymmetric properties have been synthesized and characterized by several techniques of powder and single-crystal X-ray diffraction, infrared IR and UV–Visible spectroscopies, and calorimetric (DSC) and the thermogravimetric (TG) analysis. The crystallization of this hybrid compound was found in a monoclinic system with a P21 space group. Additionally, the optimized structures of cation, anion and compound by using hybrid B3LYP method with 6-311++G(d,p) and 6-31+G(d) basis sets shown good correlations with the experimental data and the complete vibrational assignments and force constants are reported for three species. The surface morphology and the micrographs were checked by the scanning electron microscopy (SEM). The UV–Visible absorption spectrum has been used to study the optical properties and the energy gap of our compound. Hirshfeld surface (HS) analysis associated matched up with 2D fingerprint plots were used to confirm the existence of intermolecular and non-covalent interactions in the compound and confirmed by several topological approaches: Quantum Theory of Atom-in-Molecules (QTAIM), reduced density gradient (RDG) and molecular electrostatic potential surface (MEP). The frontier molecular orbitals HOMO and LUMO have been investigated for chemical reactivity and kinetic stability.

Molecular modelling of Al24N24 nanocage for the chemical sensing of phosgene and mustard chemical warfare agents: First theoretical framework

This research uses the efficiency of nanostructured Al24N24 for the rapid detection and sensing of phosgene and mustard chemical warfare agents (CWA). Frontier molecular orbitals (FMO), natural bond orbitals (NBO), density of states (DOS), topological analysis like non-covalent interactions (NCI) and quantum theory of atoms in molecules (QTAIM), sensing mechanism, and recovery time analysis were used to assess the adsorbing capabilities of the investigated Al24N24-nanocage. Mustard gas adsorption energy was strongest, ranging between −25.064 to –22.928 Kcal. Phosgene complexes had lower adsorption energies than mustard complexes ranging from −12.818 to −5.422 Kcal. The Frontier molecular orbitals (FMO) study demonstrates that phosgene and mustard gas adsorption on Al24N24 nanocage reduces the energy gap. Adsorption of phosgene results in the lowest energy gap of 2.91 eV (-29 %) for three complexes, namely P-Cl@4m, PO@6m, and P-planer@4m; hence, a much better sensing response 2.77 × 10−1 and a quicker recovery time of 3.93 × 10−10sec. These complexes have high softness (0.344 eV), low hardness (1.455 eV) and chemical potential of (-4.721 eV), which indicate high reactivity and low stability. Consequently, the Al24N24 nanocage is recommended as a fine future sensor for sensing phosgene and mustard CWA, with a much better response for phosgene.

Triquinoxalinylene and benzoquinone based covalent organic framework as robust material for mitigation of environmental pollutants-A theoretical approach

The physisorption of pollutant gases (NH3, HCN, H2S and PH3) on TQBQ-COF has been explored using DFT calculations. The strength and nature of interactions were determined through interaction energy, non-Covalent interactions- Reduced Density Gradient (NCI-RDG) plots, Frontier Molecular Orbital (FMO), Natural bond orbital (NBO), Electron Density Difference (EDD) and Quantum Theory of Atoms In Molecule (QTAIM) analysis. The optimized geometries and interaction energy calculations revealed that the analytes interacted with Oxygen and Nitrogen atoms of TQBQ-COF leading to adsorption energy ranging from −10.66 to −5.85 kcal/mol. The values of recovery time were in agreement to that of interaction energy and decreased with the increase in temperature. The NCI-RDG plots and QTAIM analysis revealed the presence of weak van der Waals forces in all complexes and partial covalent character in H2S@TQBQ-COF. Charge transfer study (employing NBO and EDD analysis) depicted the transfer of charge from surface to analytes. The study of HOMO-LUMO energy gap in FMO analysis depicted the high sensitivity of TQBQ-COF for H2S and NH3 compared to HCN and PH3 due to significant lowering of HOMO-LUMO energy gap upon the adsorption of H2S and NH3 on TQBQ-COF.

Luminescent heterobimetallic Au(I)/Ag(I) complex stabilized by a unique acetylide fragment: A spectroscopic and computational study of aurophilic ‒ argentophilic interactions

This paper investigates the luminescence and metallophilic interaction in the heterobimetallic Au(I)-Ag(I) acetylide cluster [Au2Ag2(CCPh)4(PPh3)2]. Analysis using single-crystal X-rays shows short Au∙∙∙Ag separations (2.8806(3)-3.0212(3) Å), showing favorable closed shell (d10⋯d10) aurophilic-argentophilic interactions. DFT calculations and ELF analysis reveal electron localization between Au⋯Ag contacts and electron density dispersion around gold and silver ions. Quantum Theory of Atoms in Molecules (QTAIM) research reveals electron density at bond critical points (bcp) and assesses Au(I)⋯Ag(I) interaction strengths. Natural Bond Orbital (NBO) analysis identifies donor–acceptor characteristics of orbitals involved in aurophilic ‒ argentophilic interactions.

Theoretical design of transition metal-doped oxo-triarylmethyl as a disposable platform for adsorption of ibuprofen

Emerging environmental contaminants have become a crucial environmental issue because of the highly toxic effluents emitted by factories. Ibuprofen (IBP), as a typical anti-inflammatory drug, is frequently detected in water sources. Therefore, its removal using various adsorbents has drawn great interest. Herein, the structural, electronic, energetic, and optical properties of pristine oxo-triarylmethyl (oxTAM) and transition metal-doped oxo-triarylmethyl (TM@oxTAM, TM = Sc, Ti, V, Cr, and Mn) for adsorption of the IBU drug were investigated using density functional theory (DFT) calculations implemented in Gaussian and VASP codes. Frontier molecular orbital (FMO), density of states (DOS), and electronic band structure results demonstrated that transition metal-doped oxTAM causes a significant reduction in the energy band gap (Eg) value of pristine oxTAM, with the highest decrease (30.14 %) in the case of Mn@oxTAM. It was found that transition metal doping onto oxTAM leads to an increase in the adsorption energies (1.20–2.64 eV) and charge density between transition metal and IBU. Natural bond orbital (NBO) analysis revealed that charge was effectively transferred from the IBU towards the transition metal, which was further analyzed by charge decomposition analysis (CDA). Furthermore, quantum theory of atoms in molecules (QTAIM), interaction region indicator (IRI), electron localization function (ELF), and radial distribution function (RDF) analyses revealed that the IBU is adsorbed on the Sc@oxTAM surface via covalent interactions, while electrostatic with partially covalent interactions are dominated in other IBU/TM@oxTAM complexes. The results suggest that TM doping on the oxTAM provides a new insight for developing photocatalyst-based covalent organic frameworks (COFs) to remove emerging pollutants in wastewater.

The Equilibrium Molecular Structure of Cyclic (Alkyl)(Amino) Carbene Copper(I) Chloride via Gas-Phase Electron Diffraction and Quantum Chemical Calculations.

Copper-centered carbene-metal-halides (CMHs) with cyclic (alkyl)(amino) carbenes (CAACs) are bright phosphorescent emitters and key precursors in the synthesis of the highly promising class of the materials carbene-metal-amides (CMAs) operating via thermally activated delayed fluorescence (TADF). Aiming to reveal the molecular geometry for CMH phosphors in the absence of the intermolecular contacts, we report here the equilibrium molecular structure of the (CAAC)Cu(I)Cl (1) molecule in the gas-phase. We demonstrate that linear geometry around a copper atom shows no distortions in the ground state. The structure of complex 1 has been determined using the electron diffraction method, supported by quantum chemical calculations with RI-MP2/def2-QZVPP level of theory and compared with the crystal structure determined by X-ray diffraction analysis. Mean vibrational amplitudes, uij,h1, and anharmonic vibrational corrections (rij,e • rij,a) were calculated for experimental temperature T = 20 °C, using quadratic and cubic force constants, respectively. The quantum theory of atoms in molecules (QTAIM) and natural bond order (NBO) analysis of wave function at MN15/def2TZVP level of theory revealed two Cu…H, three H…H, and one three-center H…H…H bond paths with bond critical points. NBO analysis also revealed three-center, four-electron hyperbonds, (3c4e), [π(N-C) nπ(Cu) ↔ nπ(N) π(N-Cu)], or [N-C: Cu ↔ N: C-Cu] and nπ(Cu) → π(C-N)* hyperconjugation, that is the delocalization of the lone electron pair of Cu atom into the antibonding orbital of C-N bond.