Including Dispersion Corrections Research Articles

Structural, Vibrational Spectroscopic and Theoretical (DFT) Studies of 4-Chloro- and 5-Chloro-7-azaindole-3-carbaldehydes

Molecular structures of 5-chloro-7-azaindole-3-carbaldehyde (5Cl7AICA) and 4-chloro-7-azaindole-3-carbaldehyde (4Cl7AICA) were investigated using infrared and Raman spectroscopy supported by density functional theory (DFT) calculations. Theoretical studies were carried out with three DFT methods, which include dispersion corrections: B3LYP-D3, PBE0-D3, and ωB97X-D. A single-crystal X-ray diffraction analysis was performed for 5Cl7AICA. The compound crystallizes in the monoclinic system, space group P21/c, with lattice parameters a = 3.82810(12) Å, b = 12.7330(3) Å, c = 15.9167(5) Å, and β = 94.539(3)°, with Z = 4. Within the crystal lattice, 5Cl7AICA molecules form dimers via dual and strong N1–H1⋅⋅⋅N7′ hydrogen bonds, accompanied by other intermolecular interactions. In the DFT calculations, two types of dimers of the investigated molecules were analyzed: dimer 1, which is present in the crystal structure of 5Cl7AICA, and dimer 2 displaying a 180° rotation of the aldehyde group compared to dimer 1. Computational results indicate that dimer 1 is more stable than dimer 2 for 5Cl7AICA, whereas dimer 2 is more stable than dimer 1 for 4Cl7AICA molecules. Furthermore, experimental and theoretical vibrational spectra were examined to elucidate the influence of internal rotation of the aldehyde group on spectroscopic properties.

Structural, Vibrational Spectroscopic and Theoretical (DFT) Studies of 4-Chloro- and 5-Chloro-7-azaindole-3-carbaldehydes

Molecular structures of 5-chloro-7-azaindole-3-carbaldehyde (5Cl7AICA) and 4-chloro-7-azaindole-3-carbaldehyde (4Cl7AICA) were investigated using infrared and Raman spectroscopy supported by density functional theory (DFT) calculations. Theoretical studies were carried out with three DFT methods, which include dispersion corrections: B3LYP-D3, PBE0-D3, and ωB97X-D. A single-crystal X-ray diffraction analysis was performed for 5Cl7AICA. The compound crystallizes in the monoclinic system, space group P21/c, with lattice parameters a = 3.82810(12) Å, b = 12.7330(3) Å, c = 15.9167(5) Å, and β = 94.539(3)°, with Z = 4. Within the crystal lattice, 5Cl7AICA molecules form dimers via dual and strong N1–H1⋅⋅⋅N7′ hydrogen bonds, accompanied by other intermolecular interactions. In the DFT calculations, two types of dimers of the investigated molecules were analyzed: dimer 1, which is present in the crystal structure of 5Cl7AICA, and dimer 2 displaying a 180° rotation of the aldehyde group compared to dimer 1. Computational results indicate that dimer 1 is more stable than dimer 2 for 5Cl7AICA, whereas dimer 2 is more stable than dimer 1 for 4Cl7AICA molecules. Furthermore, experimental and theoretical vibrational spectra were examined to elucidate the influence of internal rotation of the aldehyde group on spectroscopic properties.

Metallocene-Naphthalimide Derivatives: The Effect of Geometry, DFT Methodology, and Transition Metals on Absorption Spectra.

In the present paper, the photophysical properties of metallocene-4-amino-1,8-naphthalimide-piperazine molecules (1-M2+), as well as their oxidized and protonated derivatives (1-M3+, 1-M2+-H+, and 1-M3+-H+), where M = Fe, Co, and Ni, were studied via DFT and TD-DFT, employing three functionals, i.e., PBE0, TPSSh, and wB97XD. The effect of the substitution of the transition metal M on their oxidation state, and/or the protonation of the molecules, was investigated. The present calculated systems have not been investigated before and, except for the data regarding their photophysical properties, the present study provides important information regarding the effect of geometry and of DFT methodology on absorption spectra. It was found that small differences in geometry, specifically in the geometry of N atoms, reflect significant differences in absorption spectra. The common differences in spectra due to the use of different functionals can be significantly increased when the functionals predict minima even with small geometry differences. For most of the calculated molecules, the main absorption peaks in visible and near-UV areas correspond mainly to charge transfer excitations. The Fe complexes present larger oxidation energies at 5.4 eV, whereas Co and Ni complexes have smaller ones, at about 3.5 eV. There are many intense UV absorption peaks with excitation energies similar to their oxidation energies, showing that the emission from these excited states can be antagonistic to their oxidation. Regarding the use of functionals, the inclusion of dispersion corrections does not affect the geometry, and consequently the absorption spectra, of the present calculated molecular systems. For certain applications, where there is a need for a redox molecular system including metallocene, the oxidation energies could be lowered significantly, to about 40%, with the replacement of the iron with cobalt or nickel. Finally, the present molecular system, using cobalt as the transition metal, has the potential to be used as a sensor.

Electronic structure theory on modeling short-range noncovalent interactions between amino acids.

While short-range noncovalent interactions (NCIs) are proving to be of importance in many chemical and biological systems, these atypical bindings happen within the so-called van der Waals envelope and pose an enormous challenge for current computational methods. We introduce SNCIAA, a database of 723 benchmark interaction energies of short-range noncovalent interactions between neutral/charged amino acids originated from protein x-ray crystal structures at the "gold standard" coupled-cluster with singles, doubles, and perturbative triples/complete basis set [CCSD(T)/CBS] level of theory with a mean absolute binding uncertainty less than 0.1 kcal/mol. Subsequently, a systematic assessment of commonly used computational methods, such as the second-order Møller-Plesset theory (MP2), density functional theory (DFT), symmetry-adapted perturbation theory (SAPT), composite electronic-structure methods, semiempirical approaches, and the physical-based potentials with machine learning (IPML) on SNCIAA is carried out. It is shown that the inclusion of dispersion corrections is essential even though these dimers are dominated by electrostatics, such as hydrogen bondings and salt bridges. Overall, MP2, ωB97M-V, and B3LYP+D4 turned out to be the most reliable methods for the description of short-range NCIs even in strongly attractive/repulsive complexes. SAPT is also recommended in describing short-range NCIs only if the δMP2 correction has been included. The good performance of IPML for dimers at close-equilibrium and long-range conditions is not transferable to the short-range. We expect that SNCIAA will assist the development/improvement/validation of computational methods, such as DFT, force-fields, and ML models, in describing NCIs across entire potential energy surfaces (short-, intermediate-, and long-range NCIs) on the same footing.

Distribution of multiple Al substitution in HY zeolite and Brønsted acid strength - A periodic DFT study

In petrochemical industry, zeolites as solid acid catalysts play an important role and Y zeolites with high surface area and large pore openings are mainly used for catalytic cracking. Aiming at the problem that the specific positions of Al atoms in zeolites cannot be accurately distinguished experimentally and the acid strength can only be studied qualitatively, we used computational model and method to study the position of Al substitution and the resulted acid strength of Y zeolite at atomic and molecular level. The position of Al substitution with gradually decreasing Si/Al ratio (Si/Al = 47–2.4) and the corresponding Brønsted acid strength of the resulting multiple acid sites of HY zeolites are systematically investigated based on periodic DFT calculation including dispersion correction (GGA-PBE-D3). The thermodynamically more stable structures prefer Al distribution having the next-nearest neighbor of aluminum atom pairs (Al–O–Si–O–Al), and based on these stable configurations, the adsorption of ammonia (NH3) and pyridine (C5H5N) has been computed to estimate the Brønsted acid strength. It is found that the adsorption of NH3 and C5H5N prefers the formation of ammonium (NH4+) and pyridinium (C5H5NH+) ions at each acid sites and the adsorption enthalpy does not correlate with the Bader charge of the acid proton. Most importantly, the adsorption enthalpy decreases with the decrease of Si/Al ratio, indicating that the more the Al substitution the weaker the Brønsted acid strength. It is noted that the adsorption enthalpy of all individual acid sites at a given Si/Al ratio can differ strongly, despite the formation of NH4+ and C5H5NH + ions, indicating their mutual interaction and local confinement effect. The calculated adsorption enthalpies agree fully with the experimentally measured results (Si/Al = 8.6–2.4). Hyroxyl nest, defect sites formed from dealumination, has much weaker acid strength than the Brønsted acid sites. Our results provide a rational basis for further studies on the enhanced catalytic activity of HY zeolites with different Si/Al ratios.

B and Au doped ZnO and ZnO/Cu(111) bilayer films: A DFT investigation

AbstractsThe structural and electronic properties of B and Au doped graphite‐like ZnO and ZnO/Cu(111) bilayer films have been investigated by using the DFT + U scheme including dispersion correction and compared to that of undoped materials. The differences in electronic properties of the B and Au doped ZnO and ZnO/Cu(111) films compared to undoped materials were probed by CO adsorption. The same oxidation state of B (+3) was observed for B doped ZnO and ZnO/Cu(111) bilayer films. However, an excess electron associated with B doping is delocalized over the conduction band of ZnO, while it transfers to underlying Cu support of ZnO/Cu(111). This is evidenced by a much large redshift of CO frequency on B doped ZnO versus the small redshift of CO frequency on B doped ZnO/Cu(111). At variance, the oxidation state of Au dopant was reduced from +2 (5d9) for Au doped ZnO to +1 (5d10) for Au doped ZnO/Cu(111) films. This is due to the charge transfer from Cu support to doped Au which results in the stronger binding of CO on Au doped ZnO/Cu(111) compared to ZnO bilayer films. However, a slight difference in CO frequency was found for CO bound to Au doped ZnO and ZnO/Cu(111).

Theoretical investigation of [Ru(bpy)2(HAT)]2+ (HAT = 1,4,5,8,9,12-hexaazatriphenylene; bpy = 2,2′-bipyridine): Photophysics and reactions in excited state

In this article, Density Functional Theory based calculations, including dispersion corrections, PBE0(D3BJ)/Def2-TZVP(-f), were performed to elucidate the photophysics of the [Ru(bpy)2(HAT)]2+ complex in water. In addition, the thermodynamics of the charge and electron transfer excited state reactions of this complex with oxygen, nitric oxide and Guanosine-5′-monophosphate nucleotide (GMP) were investigated. The first singlet excite state, S1, strongly couples with the second and third triplet excited states (T2 and T3) giving rise to a high intersystem crossing rate of 6.26 × 1011 s−1 which is ∼106 greater than the fluorescence rate decay. The thermodynamics of the excited reactions revealed that all electron transfer reactions investigated are highly favorable, due mainly to the high stability of the triply charged radical cation 2PS•3+ species formed after the electron has been transferred. Excited state electron transfer from the GMP nucleotide to the complex is also highly favorable (ΔGsol = −92.6 kcal/mol), showing that this complex can be involved in the photooxidation of DNA, in line with experimental findings. Therefore, the calculations allow to conclude that the [Ru(bpy)2(HAT)]2+ complex can act in Photodynamic therapy through both mechanisms type I and II, through electron transfer from and to the complex and triplet–triplet energy transfer, generating ROS, RNOS and through DNA photooxidation. In addition, the work also opens a perspective of using this complex for the in-situ generation of the singlet nitroxyl (1NO−) species, which can have important applications for the generation of HNO and may have, therefore, important impact for physiological studies involving HNO.

Theoretical treatment of IO-X (X = N2, CO, CO2, H2O) complexes.

Iodine monoxide (IO) is an important component of the biogeochemical cycle of iodine. For instance, it is present in the troposphere, where it plays a crucial role in the physical chemical processes involving iodine containing compounds. Here, we present a theoretical study on a series of atmospherically relevant complexes of IO with N2, CO, CO2 and H2O, where their structural and spectroscopic properties and their interaction energies are computed. Calculations are carried out by means of ab initio post Hartree-Fock (RCCSD(T) and RMP2) methods and density functional theory DFT (PBE0 and M05-2X) based approaches with and without the inclusion of dispersion correction. After comparison to RCCSD(T), we highlight the good performance of M05-2X(+D3) DFT in describing the bonding between IO and X (X = N2, CO, CO2, H2O). Moreover, we found that the IO-X (X = N2, CO, CO2, H2O) complexes are formed by non-covalent interactions between the two monomers. In sum, we characterized two types of complexes: I-bonded and O-bonded, where the former is more stable. The atmospheric implications of the present findings are also discussed such as in the formation of the iodine oxide particles (IOPs).

β-cyclodextrin-lenalidomide anticancer drug delivery nanosystem: A quantum chemical approach

β-cyclodextrin (β-CD) has been widely used as a nanocarrier for anticancer drugs due to its convenient shape and size. The therapeutic agents can be loaded into the cavity or on the wider side of β-CD. Eight different configurations (β-CD/LND1-8) were optimized at B3LYP/6-31G(d,p) to investigate the interaction between the anticancer drug lenalidomide (LND) and β-CD in aqueous solution. The binding energies were also calculated using M06-2X density functional level of theory to include dispersion corrections. These energies indicated that the adsorption of LND on the wider side of β-CD leads to more stable configurations (β-CD/LND4-6). The reason is related to hydrogen bonds, which were studied in detail by quantum theory of atoms in molecules (QTAIM). Proper length (≈10 Å) and functional groups of LND cause that in addition to inside the cavity, it is well adsorbed on the wider side of β-CD. Quantum molecular descriptors demonstrated that the electronic structure of LND in the presence of β-CD does not change much, which is favorable for drug delivery systems. According to the results, it is predicted that β-CD is a suitable nanocarrier for LND. These results can be generalized to drugs with similar lengths and functional groups.

Adsorption and coadsorption of H and Li on Ag(100) surface: DFT studies including dispersion correction

We report on the results of DFT calculations of H, Li adsorption and Li+H coadsorption on Ag(100) surface. By using the GGA–PBE functional and DFT+d3, we obtain the adsorption energies, coadsorption energies, structural parameters, work function change and dipole moments. Our GGA–PBE calculations show that H prefers the bridge site at 0.25 and 0.50 ML coverages but hollow site at 0.75 and 1.00 ML coverages. With the DFT+d3 functional, we find that H is most stable at bridge site at 0.25 ML coverage, however, it prefers the hollow site at 0.50 ML, 0.75 ML and 1.00 ML coverages. For Li adsorption, both GGA–PBE and DFT+d3 functionals show that Li is most stable at hollow site. For Li and H coadsorption, we find that Li at the hollow site with H at the nearest-neighbor bridge site as the most energetically favorable configuration. The evolution of local electronic structures of the adsorbates and Ag(100) surface has been analyzed in terms of local density states. Our calculations show a decrease in the work function when Li and H are coadsorbed on the Ag(100) surface which suggests a possible transfer of electron from the Li-H adsorbates to the Ag(100) surface.

The mechanism of sorbitol dehydration in hot acidic solutions.

Sugar alcohol dehydration in hot water is an important reaction that allows for environmentally friendly biomass conversion without the use of organic solvents. Here, we report a free-energy analysis by metadynamics (MTD) simulations based on ab initio density functional theory and semiempirical density-functional tight-binding method to understand the mechanism of dehydration reactions of d-sorbitol (SBT) in hot acidic water. Comparing the results of ab initio and semiempirical MTD, it was found that the latter gives a reliable free energy surface of SBT dehydration reaction, although the results vary upon the inclusion of dispersion correction. It was found that the reaction proceeds consistently via an SN 2 mechanism, whereby the free energy of protonation of the hydroxyl group created as an intermediate is affected by the acidic species. This mechanism was further verified by real-time trajectories started from the transition state using ab initio molecular dynamics simulations. The free energy barriers of the reaction pathways leading to five-membered ether products are lower than those leading to six-membered ether products, in agreement with experiment. This outcome can be ascribed, in part, to our finding that the reaction barrier of the pathway is correlated to the stability of the SBT confined conformation at the initial stage of the reaction.

Adsorption properties of amino acid-based ionic liquids (AAILs) on edge fluorinated graphene surface – a DFT study

ABSTRACT We have investigated the adsorption properties of amino acid-based ionic liquids (AAILs) on edge fluorinated graphene surface (FG). Adsorption of organic ILs on the FG surface occurs via hydrogen bonds (X-H···FC), electrostatic interactions, and π···π interactions. There are large charge transfers between the interfaces, primarily from the lone pair of the fluorine (C-F bond) to the X-H (X = C, N, O) bond of both cations/anions AAILs. These non-conventional reversible hydrogen bridges are essential in surface interactions. However, substantial charge transfer occurs to cations and anions in both aromatic and aliphatic systems, respectively. Interestingly, aromatic AAILs are firmly physisorbed than aliphatic ILs. The inclusion of dispersion corrections increases the accuracy of total binding energy contributions from multiple adsorption interactions and predicts the complex's kinetic stability. Molar volume values determine the materiality of AAIL/FG to bulk systems.

Investigation on Atomic Structure and Mechanical Property of Na- and Mg-Montmorillonite under High Pressure by First-Principles Calculations

Montmorillonite is an important layered phyllosilicate material with many useful physicochemical and mechanical properties, which is widely used in medicine, environmental protection, construction industry, and other fields. In order to a get better understanding of the behavior of montmorillonite under high pressure, we studied its atomic structure, electronic and mechanical properties using density functional theory (DFT), including dispersion corrections, as function of the interlayer Na and Mg cations. At ideal condition, the calculations of lattice constants, bond length, band structure, and elastic modulus of Na- and Mg-montmorillonite are in good agreement with the experimental values. Under high pressure, the lattice constants and major bond lengths decreased with increasing pressure. The calculated electronic properties and band structure show only a slight change under 20 GPa, indicating that the effect of pressure on the electronic properties of Na- and Mg-montmorillonite is weak. The bulk modulus, shear modulus, Young’s modulus, shear wave velocity and compression wave velocity of Na- and Mg-montmorillonite are positively correlated with the external pressure, and the other mechanical parameters have a little change. The calculated studies will be useful to explore experiments in the future from a purely scientific point of view.

Benchmarking density functional theory methods for modelling cationic metal–argon complexes

Noble gas chemistry is fascinating because noble gases can make formal chemical bonds with metal ions, despite their closed electronic configuration. Argon–metal ion complexes are particularly interesting since their bonding is halfway between dispersion and covalent interactions. Although many metal ion–noble gas complexes have been synthesized, there are still disagreeing theoretical descriptions about their bonding, which is not yet fully understood. Accurate experimental data are important as solid reference for theoretical methodologies, but such data are currently scarce for complexes of a metal ion with noble gas atoms. We measured infrared spectra of MArn+ (n = 3–5; M = Au, Ag, Pd) complexes and used these spectra as benchmark data for different theory levels within the density functional theory formalism. Several basis sets, exchange–correlation functionals, and the inclusion of dispersion corrections were considered. The agreement between the measured spectra and the calculations strongly depends on the applied level of theory. Functionals of a higher level of complexity do not consistently provide a better agreement with the experiment; this is particularly the case for the B3LYP hybrid functional that performs worse than the PBE GGA functional. On the other hand, the inclusion of dispersion corrections and the use of a large basis sets are crucial for a good description of the interaction between M+ and argon atoms.

Solvent engineered synthesis of layered SnO for high-performance anodes

Batteries are the most abundant form of electrochemical energy storage. Lithium and sodium ion batteries account for a significant portion of the battery market, but high-performance electrochemically active materials still need to be discovered and optimized for these technologies. Recently, tin(II) oxide (SnO) has emerged as a highly promising battery electrode. In this work, we present a facile synthesis method to produce SnO microparticles whose size and shape can be tailored by changing the solvent nature. We study the complex relationship between wet-chemistry synthesis conditions and resulting layered nanoparticle morphology. Furthermore, high-level electronic structure theory, including dispersion corrections to account for van der Waals forces, is employed to enhance our understanding of the underlying chemical mechanisms. The electronic vacuum alignment and surface energies are determined, allowing the prediction of the thermodynamically favoured crystal shape (Wulff construction) and surface-weighted work function. Finally, the synthesized nanomaterials were tested as Li-ion battery anodes, demonstrating significantly enhanced electrochemical performance for morphologies obtained from specific synthesis conditions.

Preparation, characterization and adsorption properties of tetraalkylphosphonium organobeidellites

New intercalated clay materials based on the combination of four systematically selected alkylphosphonium organocations and beidellite (Bd) were prepared. Particularly, tetraethyl-, tetrabutyl-, tetrahexyl- and tetraoctyl- phosphonium cations were used in the synthesis. The samples were characterized by X-ray diffraction, thermal analysis, infrared spectroscopy and elemental carbon analysis. Further, calculations based on density functional theory method including dispersion corrections (DFT-D3) were carried out in a prediction of stability and detailed characterization of the structure and interactions of the beidellite intercalated models corresponding to four tetraalkylphosphonium cations used in experiment (4PX-Bd; X = 2, 4, 6, 8 / ethyl-, butyl-, hexyl-, octyl-). Calculated interlayer distances (d001) for all four models agreed well with experimental data continuously growing with a length of the alkyl chains of the 4PX cations. The structural stability of 4PX-Bd intercalates also increased with the size of the 4PX cations. Calculated vibrational spectra obtained from ab initio molecular dynamics were in a good agreement with experimental IR spectra. Further, a sorption capacity of synthetized organobeidellites was probed by loading sulfamethoxazole drug and quantified by liquid chromatography method. Adsorption of sulfamethoxazole was the most effective using tetraoctylphosphonium-modified beidellite.

Theoretical design coupled with experimental study of the effectiveness of the inhibitive molecules based on Cynara scolymus L extract toward chloride-induced corrosion of steel

The application of corrosion inhibitors on metallic surfaces is sorely vital for increased longevity with lessened maintenance costs. In this paper, Cynara scolymus L extract was tested as a green/bio-degradable corrosion inhibitor for mild steel in sodium chloride solution by using electrochemical techniques. Hence, the ultraviolet-visible spectrophotometry (UV–Vis) and Fourier transform infrared (FT-IR) spectroscopy were conducted for Cynara scolymus L extract characterization. The electrochemical results indicated that the values of corrosion current density and double-layer capacitance decreased as time increased. The polarization results revealed that the nature of Cynara scolymus L adsorption is mixed with dominantly anodic. The results also suggest that the inhibition power is 96.1% at 1000 ppm in the sodium chloride solution. The corrosion inhibiting action of the Cynara scolymus L is ascribed to the process prohibition due to the surface film formation over the mild steel surface. The computer modeling (including molecular dynamics (MD), density functional theory including dispersion corrections (DFT-D), and Monte Carlo (MC)) achievements further supported the adsorption of Cynara scolymus L molecules on the mild steel surface. Furthermore, the DFT-D calculations suggested the adsorption of the inhibitor via electronic donor-acceptor interactions. As a result, the Cynara scolymus L is a practical green/bio-degradable inhibitor that helps to tailor the corrosion obstacles of mild steel for injection water and cooling systems.

How many shades of grey? On the proximity of density functional approximation to ab initio method via calculations of electric multipole moments

The wide spreading of the application of Density Functional Approximation via its represtnatives, i.e. the Density Functionals (DFs), in almost all the fields of computational chemistry is globally witnessed. Therefore, it is believed that an evaluation of their performance in tedious calculations will offer useful insights to both users and developers. As such calculations we chose the prediction of electric multipole moments of first to fourth order, namely dipole (µ α /ea 0), quadrupole , octupole and hexadecapole . Values at both ab initio up to the highly accurate couple cluster with singles and doubles (reference values) as well as different flavors of DFs: hybrid, GGA, double hybrid, long range corrected, including dispersion correction, both hybrid and long range corrected and some from the Minessota family. The target set is a group of 10 molecules of C 2 ν symmetry. The results were further analyzed with the root mean square deviation (RMSD) method as to find the method that is the most proximal to reference CCSD. The functionals PBE1PBE, CAM-B3LYP and B2PLYP seem to survive the proximity test, whereas B97D, M05, M06 and M08 provide results that are the least proximal to CCSD ones.

Pyridine and Methylpyridines: Calculations of the Structure, Proton Affinity, Gas-Phase Basicity, and Mobility of Protonated Molecules and Proton-Bound Dimers

Accurate calculations of the structure and properties of analytes and their ions are of great interest to the theory and practice of mass spectrometry, ion mobility spectrometry, and related methods. In this work, using accurate quantum chemical methods, we computed the structure of neutral and protonated pyridine, 2-methyl-, 4-methyl-, 2,4-dimethyl-, 2,6-dimethyl-, and 2,4,6-trimethylpyridine molecules and also of proton-bound dimers of pyridine and 2,4-dimethylpyridine. Two stable conformers of the 2,4-dimethylpyridine proton-bound dimer are found. An accurate and economical method is proposed for calculating proton affinity and gas-phase basicity with the calculation error close to the experimental one. The values of proton affinity and gas-phase basicity for 2,4,6-trimethylpyridine are computed. Reduced mobilities of protonated molecules and proton-bound dimers are calculated by the trajectory method in different versions. A calculation version is proposed that allows mobility computation with the error close to the experimental one and adequately reproduces small differences in the mobility of isomers. The versatility of the chosen B3PW91−D3BJ/def2−TZVP method of the density functional theory with the inclusion of dispersion correction is shown. The method (in combination with B2GP−PLYP−D3BJ/def2−TZVPPD calculations) ensures accurate calculations of the molecular structure, proton affinity, and gas-phase basicity, and also charges on atoms for computing ion mobility.

Spectroscopic, Structural, DFT and Molecular Docking Studies on Novel Cocrystal Salt Hydrate of Chromotropic Acid and Its Antibiofilm Activity

A novel organic cocrystal salt hydrate (CTPTH) of Chromotropic acid with 1,10-phenanthroline was successfully obtained using both traditional solution method and liquid-assisted grinding method, a green approach. The formation and characterization were done by Powder x-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, and the structural confirmation by single crystal x-ray diffraction. The molecular properties were studied using density functional theory, B3LYP/def2-SVP including dispersion correction (D3) to calculate the HOMO and LUMO energies using Orca and Gaussian packages. The calculated geometric parameters were in good agreement with those of experimentally observed. The non-bonding interaction between the CTPTH and active site of the crystal structure of quorum-quenching N-Acyl homoserine lactone lactonase (PDB: 2BR6) in bacterium was studied by molecular docking. The total energy of ligand interaction of CTPTH with the receptor is found to be − 42.78 kcal mol−1. The Hirshfeld surfaces were mapped over dnorm for the identification and quantification of robust synthons for a better understanding of the overall packing pattern of CTPTH. In addition, the antibiofilm efficacy of CTPTH against the pathogenic bacterium Pseudomonas aeruginosa was also determined.