Basis Set Superposition Error Correction Research Articles

Modeling of butyric acid recognition by molecular imprinted polyimide.

The constitutional repeating unit structures of poly(pyromellitic dianhydride-co-4,4'-oxydianiline) or polyamiс acid, butyric acid and complexes between butyric acid and one, two or three units of polyamiс acid were calculated using the density functional theory method (DFT B3LYP) on a 6-31G(d,p) basis with the basis set superposition error (BSSE) correction in the program Gaussian 09. The optimised structures of the template and polyamiс acid allowed to establish intermolecular non-covalent interactions during imprinting and, based on the results, develop a method of polyimide-based molecularly imprinted polymer preparation using butyric acid as template. It was shown that the optimum molar ratio of reagents used for the synthesis of molecularly imprinted polymer is 1:1 (interaction energy ∆E = 43.2kJ/mol). In the presence of a large number of polyamic acid units in prepolymerisation complexes, the self-association of polyamic acid and the steric hindrance, which reduce the stability of the complexes, occur. The simulation results are in good agreement with experimental data. When analysing the energy values and parameters of bonds of the complexes, it was shown that butyric acid interacts with carboxyl groups from units of polyamiс acid via hydrogen bonding of moderate strength. The IR spectra of a complex between structural unit of polyamic acid and butyric acid were also obtained in order to understand the intermolecular interactions responsible for the molecular recognition. According to the IR spectra, it was shown that the vibrations of the C=O and O-H groups of butyric acid and polyamic acid participating in the interaction are weakened; their vibration frequencies are reduced. The polyimide structure was also constructed in the work. It was shown that two polyimide chains interact with each other due to hydrogen bonds between the hydrogen atoms of the benzene rings and the oxygen of the imide groups.

Combined Machine Learning and Molecular Modelling Workflow for the Recognition of Potentially Novel Fungicides.

Novel machine learning and molecular modelling filtering procedures for drug repurposing have been carried out for the recognition of the novel fungicide targets of Cyp51 and Erg2. Classification and regression approaches on molecular descriptors have been performed using stepwise multilinear regression (FS-MLR), uninformative-variable elimination partial-least square regression, and a non-linear method called Forward Stepwise Limited Correlation Random Forest (FS-LM-RF). Altogether, 112 prediction models from two different approaches have been built for the descriptor recognition of fungicide hit compounds. Aiming at the fungal targets of sterol biosynthesis in membranes, antifungal hit compounds have been selected for docking experiments from the Drugbank database using the Autodock4 molecular docking program. The results were verified by Gold Protein-Ligand Docking Software. The best-docked conformation, for each high-scored ligand considered, was submitted to quantum mechanics/molecular mechanics (QM/MM) gradient optimization with final single point calculations taking into account both the basis set superposition error and thermal corrections (with frequency calculations). Finally, seven Drugbank lead compounds were selected based on their high QM/MM scores for the Cyp51 target, and three were selected for the Erg2 target. These lead compounds could be recommended for further in vitro studies.

Experimental and theoretical spectroscopic analysis, hydrogen bonding, reduced density gradient and antibacterial activity study on 2-Phenyl quinoline alkaloid

The main objective of the study was based on combined experimental and quantum chemical computation methodology performed on spectroscopic analysis, structural activity study in order to find the antibacterial activity of 2-phenyl quinoline (2PQ) alkaloid. Solvent effect of 2PQ with water complexes (2PQ·nH2O, n = 1,2,3…7) was performed at the B3LYP/6-311G(d,p) level to investigate the different types of hydrogen bonding interactions in compound 2PQ. The optimized structural parameters of the title compound were computationally obtained at DFT/B3LYP level of theory. The interaction energies of 2PQ·H2O complexes were calculated with the basis set superposition error (BSSE) correction. The fundamental modes of vibration were examined by experimental FT-IR and FT-Raman techniques. The assignments of vibrational modes were carried out by using normal co-ordinate analysis (NCA). Stability of the molecule, intra and intermolecular hydrogen bonding and hyperconjugative interaction of 2PQ and its water complexes were also analyzed by using NBO analysis. Non-covalent interactions of 2PQ and its water complexes were studied by reduced density gradient (RDG) analysis. The UV–visible spectrum of the molecule in ethanol and water solvent were recorded and compared with calculated data. Molecular docking studies were performed to predict binding site of 2PQ with its target protein. The antibacterial activity of 2-phenyl quinoline alkaloid were tested against standard strain of the bacteria Escherichia coli and Staphylococus aureus.

Kohn-Sham Density Functional Calculations Reveal Proton Wires in the Enolization and Carboxylase Reactions Catalyzed by Rubisco.

Ribulose 1,5-bisphosphate (RuBP) carboxylase-oxygenase (Rubisco) plays a fundamental role in the carbon cycle by fixing the atmospheric CO2 used in photosynthesis. Rubisco is all the more remarkable because it must catalyze some difficult multistep reaction chemistry involving proton transfers within the one active site. In the present study, we have used Kohn-Sham density functional theory at the B3LYP/6-31G* level with basis set superposition error and dispersion corrections (B3LYP-gCP-D3) to examine the possibility that the proton transfers can take place through molecular wires (including active-site water molecules) via the classical Grotthuss proton-shuttle mechanism. The results support an essential role for water molecules found in the crystal structures of Rubisco complexes as facilitators of proton transport in all the rate-limiting (catalytic) reaction steps through a network of short proton wires within the Rubisco active site. We suggest that completion of the initial product turnover (cycle) requires two excess protons produced in the initial carbamylation that is required for Rubisco activation. By use of proton wires, a large number of reaction steps may be accommodated within a single active site without necessitating the input of excessive conformational strain energy arising from the movement of residue side chains into positions where direct protonation of substrates can occur. The involvement of the identified types of proton wires in the kinetic mechanism is capable of providing a unique explanation for various experimental observations, including deuterium isotope effects and the results of site-directed mutagenesis experiments, and may thus provide a realistic solution to the problem of Rubisco's challenging chemistry.

Evaluating role of the x–π (x = π and/or CH) stacking interactions in adsorption of the (4E,4E)-4-(4-hydroxyphenyldiazenyl)-N-((furan-2-Yl)methylene)benzenamine antibacterial in armchair boron nitride nanotube

Non-covalent interactions have been investigated in several orientations of (4E,4E)-4-(4-hydroxyphenyldiazenyl)-N-((furan-2-yl)methylene)benzenamine/armchair single-wall boron nitride nanotube [EE-HPDFMB/SWBNNT] complexes at ωB97X-D/6-31G(d) level of theory. Global reactivity indexes show electrophile and nucleophile roles of EE-HPDFMB and SWBNNT, respectively. This result confirms molecular electrostatic potential maps and low HOMOSWBNNT–LUMOEE-HPDFMB gap. These interactions as weak forces can cause a physical adsorption and encapsulation of EE-HPDFMB with medicinal properties in the SWBNNT. More negative values (− 25.7 and − 47.2 kJ mol−1) of adsorption energy including zero point energy and basis set superposition error corrections ($$D_{\text{e}}^{0}$$) in the inside complexes show better adsorption strength, stable configuration and small red shift than outside. This issue mainly results from existence of the several π–π and CH–π stacking interactions in the inside complexes. More importantly, obtained electron density ρ(r) and Laplacian ∇2ρ(r) from QTAIM analysis reveal that the π–π stacking in the inside is stronger than outside complex. Low second-order stabilization energies in the in/outside complexes are confirmation for these non-covalent interactions in electron view point.

Radiation-Induced Transformation of CHF3···CO to the CF3···CO Complex: Matrix Isolation and Ab Initio Study.

The X-ray-induced transformations of CHF3/CO/Ar and CHF3/CO/Kr systems were investigated by Fourier transform infrared (FTIR) matrix isolation spectroscopy at 6 K. It was found that addition of CO suppressed decomposition of fluoroform in an Ar matrix, probably because of trapping of matrix holes by CO and CHF3···CO complexes. Considerable increase of the CF3/CF2 ratio with increasing CO content in the matrix was attributed to stabilization of the CF3 radical with respect to further radiation-induced fragmentation because of its complexation with the CO molecule. The CF3···CO complex generated from the CHF3···CO precursor complex was characterized by FTIR spectroscopy and ab initio calculations at the CCSD(T) and MP2 levels of theory. To the best of our knowledge, it is the first experimentally observed complex of the CF3 radical. The computed interaction energy was found to be 0.35 kcal/mol at the CCSD(T)/L2a_3 level (0.36 kcal/mol at the MP2/L2a_3 level), taking into account zero-point energy and basis set superposition error corrections. Despite the very weak intermolecular bonding, the complex is characterized by distinct features in the regions of C-F symmetric and antisymmetric stretching (CF3) and CO stretching (the latter one was observed only in a krypton matrix). The geometrical structure of the radical-molecule complex is close to that of its molecular precursor.

Benchmark ab initio calculations on intermolecular structures and the exciton character of poly(p-phenylenevinylene) dimers.

Benchmark ab initio calculations have been performed for poly(p-phenylenevinylene) (PPV) dimers, a paradigmatic material for studying excitation energy transfer mechanisms. Second-order Møller-Plesset perturbation theory was utilized with the scaled opposite spin approach (SOS-MP2) and correlation consistent basis sets to determine the geometric properties and interaction energies in the ground state. Vertical excitations and optimized structures for the S1 state were computed using the SOS second-order algebraic diagrammatic construction method. For the ground state properties, extrapolation to the complete basis set (CBS) limit and correction for the basis set superposition error (BSSE) were performed. While all results computed with different basis sets and considering BSSE correction or not agreed at the CBS limit, a strong bias was observed either using augmented basis sets or BSSE corrections, proving that these approaches are not advisable for calculating intermolecular distances and interaction energies with smaller basis sets. The lower states for vertical excitations were largely local excitons where the hole/electron pair was confined to single chains. For higher excited states, interchain charge transfer (CT) states were also observed. Geometry optimization of the S1 state led to significant reductions in the intermolecular distances and energetic stabilization, with Stokes shifts between 1.4 eV and 0.9 eV (with increasing chain length), and significant CT values between 0.5e and 0.4e.

Theoretical investigation of the self-association of antitumor drug imexon

The dimers resulting from self-association of oxo-imino, oxo-amino, and hydroxyl-imino tautomers of imexon, that present two hydrogen bonds, were fully optimized with the density functional methods B3LYP, M06-2X in conjunction with 6-311++G(d,p) basis set. Additionally, second-order Moller-Plesset (MP2) level in combination with 6-311++G(d,p) basis set was employed for comparison purpose. The thermodynamic stability of the self assembled structures in gaseous phase has been obtained according to the analyses of total electronic energies and hydrogen bonding interactions. The bulk water environment has been simulated using the universal solvation model based on solute electron density (SMD). Stability and structure of homochiral and heterochiral imexon dimers resulting from the three imexon tautomers have been carried out to investigate the chiral discrimination. The imexon dimer with heterochiral configuration resulting from self-assembling oxo-amino tautomer is found to be thermodynamically most stable in both gas and aqueous phases. The interaction energies for these self assembled structures were further evaluated with the basis set superposition error corrections. The so-called seven-point interaction energy which includes corrections for BSSE and deformation was calculated. The intermolecular interactions of the selected dimers have been analyzed by calculation of electron density (ρ) and Laplacian (∇2ρ) at the bond critical points (BCPs) using atoms-in-molecule (AIM) theory.

Effect of dimer formation via hydrogen bonding on static and dynamic nonlinear optical characteristics of chromophores

AbstractThe effect of head‐to‐tail azochromophore dimer formation on the values of static and dynamic first hyperpolarizability is studied on the basis of calculations performed at M06‐2X/aug‐cc‐pVDZ and ωB97X‐D/aug‐cc‐pVDZ computational levels; the results are compared with those obtained at second‐order Moller‐Plesset pertubation theory (MP2)/aug‐cc‐pVDZ. Azochromophores DO3 and AAB‐DCV, participating in the dimer formation, contain nitro‐ or dicyanovinylene acceptor moieties. The structure of the studied dimers is obtained at the B3LYP‐D3/6‐31++G (d,p) level with basis set superposition error (BSSE) correction. Dynamic first hyperpolarizabilities are calculated at radiation frequencies of 0.65 eV, 0.918 eV and 1.165 eV. The essential effect of dimer formation is demonstrated: it results in almost a 3.5 times increase of the first hyperpolarizability. In the series D1‐D2‐D3, β(2ω) values at 0.65 eV increase in a way similar to the static case: β(2ω) for D2 and D3 are 1.5 and 1.8 times higher than that for D1. The notable resonance enhancement of β(2ω) for the studied hydrogen‐bonded dimers is demonstrated at radiation frequency of 1.165 eV.

Formation of active species from ruthenium alkylidene catalysts\u2014an insight from computational perspective

Ruthenium alkylidene complexes are commonly used as olefin metathesis catalysts. Initiation of the catalytic process requires formation of a 14-electron active ruthenium species via dissociation of a respective ligand. In the present work, this initiation step has been computationally studied for the Grubbs-type catalysts (H2IMes)(PCy3)(Cl)2Ru=CHPh, (H2IMes)(PCy3)(Cl)2Ru=CH-CH=CMe2 and (H2IMes)(3-Br-py)2(Cl)2Ru=CHPh, and the Hoveyda-Grubbs-type catalysts (H2IMes)(Cl)2Ru=CH(o-OiPrC6H4), (H2IMes)(Cl)2Ru=CH(5-NO2–2-OiPrC6H3), and (H2IMes)(Cl)2Ru=CH(2-OiPr-3-PhC6H3), using density functional theory (DFT). Additionally, the extended-transition-state combined with the natural orbitals for the chemical valence (ETS-NOCV) and the interacting quantum atoms (IQA) energy decomposition methods were applied. The computationally determined activity order within both families of the catalysts and the activation parameters are in agreement with reported experimental data. The significance of solvent simulation and the basis set superposition error (BSSE) correction is discussed. ETS-NOCV demonstrates that the bond between the dissociating ligand and the Ru-based fragment is largely ionic followed by the charge delocalizations: σ(Ru–P) and π(Ru–P) and the secondary CH…Cl, CH…π, and CH…HC interactions. In the case of transition state structures, the majority of stabilization stems from London dispersion forces exerted by the efficient CH…Cl, CH…π, and CH…HC interactions. Interestingly, the height of the electronic dissociation barriers is, however, directly connected with the prevalent (unfavourable) changes in the electrostatic and orbital interaction contributions despite the favourable relief in Pauli repulsion and geometry reorganization terms during the activation process. According to the IQA results, the isopropoxy group in the Hoveyda-Grubbs-type catalysts is an efficient donor of intra-molecular interactions which are important for the activity of these catalysts.

THEORETICAL STUDY ON THE INTERMOLECULAR INTERACTIONS OF 1,1-DIAMINO-2,2-DINITROETHYLENE WITH NH3 AND H2O

Density Functional Theory (DFT) and dispersion-corrected density functional theory (DFT-D) were used to study the intermolecular interactions of 1,1-diamino-2,2-dinitroethylene FOX-7/NH3and FOX-7/H2O supermolecules. The geometries optimized from DFT and DFT-D methods are similar.Six optimized supermolecules were characterized to be local energy minima on potential energy surfaces without imaginary frequencies. The intermolecular interaction energy (binding energy) was calculated with basis set superposition error (BSSE) correction. The largest corrected intermolecular interaction energy is FOX-7/NH3 (-43.76 kJ×mol-1), indicating that the interaction between FOX-7 and NH3 is stronger than that of FOX-7/H2O. The same conclusion is obtained from the studies on the infrared spectrum and frontier orbitals.

Theoretical insights into the hydrogen bonding interaction in the complexation of epinephrine with uracil.

The present study is aimed at probing the hydrogen bonding interaction between epinephrine and uracil by means of density functional theory calculations concerning their complexation's geometries, interaction energies, and vibrational frequencies. Geometry optimization was carried out giving 19 stable geometries of epinephrine-uracil complex with interaction energies in a range of -21.51 to -62.37kJmol-1 using the basis set superposition error (BSSE) correction. The analysis of structure and vibration shows that the hydrogen bonding elongates the length of corresponding bond O(N)-H and decreases the symmetric stretching vibrational frequency, which indicates red-shifted H-bonding interactions in all the geometries. Additionally, the analysis with theories of natural bond orbital (NBO), atoms in molecules (AIM), and the reduced density gradient (RDG) of hydrogen bonding properties and characteristics of the 19 geometries suggests that the hydrogen bonding in all the optimized structures of epinephrine-uracil complex is kind of a closed-shell interaction and mainly electrostatic dominant.

New potential energy surfaces for the complexes Ar–CuX (X = F, Cl, Br, and I)

New intermolecular potential energy surfaces (PESs) are constructed at the level of the non-iterative perturbation treatment of triple excitations [CCSD(T)] plus aug-cc-pVQZ basis set supplemented with bond functions for the complexes Ar–CuX (X = F, Cl, Br, and I) at the rigid rotor approximation. The global minimum is assigned to be a collinear Ar–Cu–X geometry, while the local minimum is an anti-linear Cu–X–Ar geometry on the PES for each complex. Based on the PESs, the intermolecular vibrations, pure rotational spectra, as well as isotope effects are investigated via the bound state calculations. We also give a detailed comparison of the structural parameters, binding energies, accuracy of PESs, as well as the results of basis set superposition error (BSSE) correction with those of Ar–AgX complexes. In addition, we construct a three-dimension (3D) intermolecular PES for the complex Ar–CuF, which not only gives the information of structural change for Cu―F distance upon the complex formation, but also reproduces the rotational spectroscopic characteristics much better.

Application of a molecularly imprinted polymer based on the polyimide as a piezosensor selective coating for determining the oleic acid in oils

When creating selective piezoelectric sensors based on the molecularly imprinted polymers (MIPs), the possibility of using quantum-chemical modeling for the selection of their synthesis conditions was considered. The starting polymer for MIPs production was polyamic acid (PAA), which is a copolymer of 1,2,4,5-benzenetetracarboxylic acid and 4,4′-diaminodiphenyl ether. Applying two-step thermal imidization of PAA solution in the presence of a template, the molecularly imprinted polyimide was formed. The oleic acid served as the template. The structures were optimized and the energies were calculated by the Gaussian 09 software using the DFT method at the B3LYP/6-31G(d,p) level with the basis set superposition error (BSSE) correction. It was shown that the structure of the fatty acid radical plays the decisive role in the formation of prints and, accordingly, in the selectivity of the polymer. Based on the quantum-chemical calculations, the optimal ratio of the reagents in pre-polymerization mixture was set to 4:1. The molecularly imprinted polymers for oleic acid have been synthesized on the surface of piezoelectric sensors by the non-covalent imprinting method. The ability of the obtained sensors to recognize this acid in the binary and ternary model mixtures of fatty acids was experimentally evaluated, and it was found that the sensor based on the molecularly imprinted polymer was most sensitive to the oleic acid, which had the detection limit of 0.14 g/dm 3 . Piezoelectric sensors based on MIPs were approved for the determination of the fatty acid in vegetable oils (sunflower, corn, olive, linseed, and rapeseed). The chromatography-mass spectrometry was used as the comparison method, and it was found that the difference in determination results was less than 10%. Keywords : molecularly imprinted polymers, polyamic acid, polyimide, oleic acid, computer modeling, modified piezosensors (Russian) DOI: http://dx.doi.org/10.15826/analitika.2019.23.1.006 Cao Nhat Linh, О.V. Duvanova, A.N. Zyablov Voronezh State University, Universitetskaya square, 1, Voronezh, 394018, Russian Federation

CHF3…H2O complex revisited: a matrix isolation and ab initio study

The structural and spectroscopic features of the CHF3…H2O complex have been investigated using high-level ab initio calculations and IR matrix isolation spectroscopy. In contrast to previous findings, the computations at the CCSD(T)/L3a_3 and MP2/L3a_3 levels of theory revealed only one structure of the complex stabilized by two C-H…O and O-H…F hydrogen bonds. The interaction energy extrapolated to a complete basis set with ZPVE and BSSE corrections is 2.73 kcal/mol at the CCSD(T) level, taking into account the zero-point vibrational energy (ZPVE) and basis set superposition error (BSSE) corrections. According to Bader’s analysis, complex exhibits a cyclic structure, which confirms the existence of ring critical point as well as bond critical points in the system. The calculated complexation-induced shifts of the fluoroform fundamentals are in good agreement with the matrix isolation results. In addition to previously reported IR absorptions of the complex, the feature corresponding to the C-F bending mode of CHF3…H2O was first observed, in good correlation with the computational predictions.

Fully optimized implementation of the cluster-in-molecule local correlation approach for electron correlation calculations of large systems.

A fully optimized implementation of the cluster-in-molecule (CIM) local correlation method for faster and more accurate electron correlation calculations of large systems is reported. The speedup comes from the new procedure of constructing virtual localized molecular orbitals of clusters. In the new procedure, Boughton-Pulay projection method is employed instead of a much more expensive Boys localization procedure. In addition, basis set superposition error correction for binding energy calculations and parallelized electron correlation calculations of clusters are now implemented. Benchmark calculations and illustrative applications at the Møller-Plesset perturbation theory, coupled cluster singles and doubles (CCSD), and CCSD with perturbative triples correction levels show that this newly optimized CIM approach is a reliable theoretical tool for electron correlation calculations of various large chemical systems. © 2018 Wiley Periodicals, Inc.

Experimental and theoretical studies on cis-dioxomolybdenum(VI) complexes of ONN-donor thiosemicarbazone

Cis-dioxomolybdenum(VI) chelate complexes with 5-chloro-2-hydroxybenzophenone S-methyl-4-phenylthiose- micarbazone (L) were synthesized in the general formula (MoO$_{2}$(L)D), where D is an odd- or even-numbered alcohol (methanol (1), ethanol (2), n-propanol (3), n-butanol (4), and allyl alcohol (5)). The structures of 1-5 were verified by elemental analysis, Fourier transform infrared (FT-IR), and $^{1}$H NMR spectra. Complex 5 crystallizes in the monoclinic space group P21/n, and its crystalline data showed a dimeric structure formed by a pair of intermolecular hydrogen bonds with 1.92 Å. These dimers are stacked in a similar crystalline structure as a single molecule. The experimental data were compared with the theoretical results obtained by the quantum chemical calculations of the DFT/B3LYP method with LANL2DZ basis set. A detailed interpretation of the FT-IR spectra of the studied compounds was performed based on the total energy distribution. In order to investigate the electronic structures and the UV-Vis spectrum of complex 5, time-dependent density functional theory calculation was taken into account. The interaction energies between the odd- and even-numbered alcohols and remaining parts of complexes 1-4 were evaluated with the help of natural bonding orbital analysis. In addition, the basis set superposition error correction energies were calculated. The results were evaluated by considering the coordinated alcohols with an even number of carbon atoms to have much higher interaction energy than the next lower homologous alcohols with an odd number of carbon atoms.

Theoretical studies of Ar–AgX (X = F, Cl, Br, I) complexes: Potential energy surfaces, intermolecualr vibrations and microwave spectra

Theoretical studies of the potential energy surfaces (PESs) and bound state calculations were performed for Ar–AgX (X = F, Cl, Br, and I) complexes. A two-dimensional intermolecular PES was constructed at the level of single and double excitation coupled-cluster method with a non-iterative perturbation treatment of triple excitations [CCSD(T)] plus aug-cc-pVQZ basis set supplemented with bond functions for each complex. The global minimum was assigned as the collinear structure of Ar–Ag–X, while the local minimum was assigned as the anti-linear structure of Ar–X–Ag. Both Ar–Ag and Ar–X distances display us an increasing trend from Ar–AgF to Ar–AgI complexes. Based on the bound state results, the intermolecular vibrational modes of collinear and anti-linear isomers were studied in detail via the wavefunction analysis. Due to the very low well depth for the anti-linear structure, an obvious delocalization effect was observed for each complex, except for Ar–AgI. Furthermore, our calculated results suggest that the anti-linear isomer of Ar–AgBr and Ar–AgI could be observed in experiment. The rotational energy levels were also determined based on the ab initio PESs via the bound state calculations. The microwave spectrum for the collinear isomer of each complex was predicted with the maximal percentage error of 1.55% for the complex Ar–AgF. A simple method of coordinate translation was used to re-interpolate the PES for each isotopomer to determine the isotope effects for Ar–AgX complexes and the deduced results are in good agreement with those of experimental observation. The microwave spectrum can be much better reproduced with an equivalent percentage error of 0.07% cm−1 for each isotopomer based on a scaled PES. Finally, we checked the effects of the basis set superposition error (BSSE) correction and core correlation, and found that the BSSE correction has great influence on the intermolecular interactions for the Ar–AgX complexes.

Extension of the atom by atom scheme of counterpoise method and presentation of its new advantages.

In this paper, for the first time, we want to clearly show that two types of binding energies, cited here as interaction energies (IEs) and stabilization energies (SEs), may need different values of basis set superposition error (BSSE) corrections. We also report the first calculation of the BSSE correction for the strain energies (ES) of supermolecular systems. For this purpose, the known atom by atom scheme of the counterpoise method was extended to mathematically show that the values of BSSE for IE versus SE of a defined system can be really different. Then the IE and SE values of some AB and ABC supermolecules were corrected for BSSE, calculated through the full counterpoise method (CPn) versus its atom by atom scheme (CPaa). The data confirmed that the CPaa accurately gives the different BSSE values for IE versus SE when there is a noticeable difference between the values of these energies. In the above case, the CPn method that gives a single value of BSSE for both IE and SE is not a suitable choice for correcting the SE values.

In English

Various quantum chemical approaches including ab initio, density functional theory (B3LYP, CAM-B3LYP, ωB97X-D, M06HF) and semiempirical (PM7) methods with different basis sets and various solvation models (SMD, IEFPCM, COSMO), as well as a supermolecular approach, and the basis set superposition error (BSSE) corrections, used to analyze the solvation effects are compared for polar (water, ethanol, dimethylsulfoxide, acetonitrile, acetone), weakly polar (chloroform) and nonpolar (benzene, n-hexane, carbon tetrachloride) solvents per se and interacting with unmodified and modified silicas. The DFT methods give smaller errors in the DG s values than the PM7 method with various solvation models. For the molecular clusters with water alone or water with organics, the interaction energy decreases with enhanced amorphism of the systems. The supermolecular approach with PM7 gives worse results (in comparison to the experimental data) than those of SMD/PM7 or COSMO/PM7. An increase in the basis sets can give worse results than that at smaller ones because the parameters in the SMD model were calibrated using the experimental data and ab initio or DFT calculations of the same systems with relatively small basis sets.