Search

In this paper, we evaluated adsorption of phosgene gas molecule (COCl2), on the hexagonal-aluminum nitride (h-AlN) nanosheet by using first-principles van der Waals density functional theory calculations (vdW-DF) method. The nature of interaction between the phosgene molecule and h-AlN is discovered by geometries, adsorption energies, Mulliken, Hirshfeld as well as Voronoi charges analyses. The density of states (DOS) was calculated and the results show that HOMO/LUMO energy gap of h-AlN is significantly reduced upon the COCl2 adsorption. The projected density of states (PDOS) of the adsorption systems suggested that the enhancement of adsorption was owing to the hybridization between Al atom of h-AlN sheet and the O atom of phosgene molecule. Interestingly, the results reveal that the Eg of h-AlN is very sensitive to the presence of COCl2 molecule as its value reduces from 3.337 eV in pure h-AlN to 1.966 eV (41.08% change) after the COCl2 adsorption which would result in electrical conductance increment. Global reactivity descriptor values such as electronegativity (χ), global hardness (η), global softness (S), electronic chemical potential (μ), electrophilicity index (ω), and electro accepting power (ω+) were calculated. Additionally, the stability of the most stable phosgene/h-AlN complex was evaluated by means of DFT molecular dynamics (MD) simulation at room temperature under constant volume and temperature conditions with PBE method. Based on the DFT calculation results, the h-AlN nano sheet is expected to be potential novel sensor for detecting the presence of COCl2 gas.

A novel magnetic Co nanoparticle catalyst was prepared by coating Fe304magnetic nanoparticles with tetraethyl orthosilicate functionalized with (3-chloropropyl)trimethoxysilane and 2-amino-5-mercapto-1,3,4-thiadiazole ligands followed by complexation with Co(OAc)4. The catalyst was then characterized and applied for the synthesis of various tetrazoles by the reactions of amines with sodium azide and triethyl orthoformate in solvent-free conditions at 100°C.

In current research, the interaction between 5-fluorouracil (FU), as an anticancer drug, and graphene was studied in the M062X/6-311G(d,p) level of theory. The external electric field effects on the total energy, dipole moment, the energies corresponding to frontier orbitals and HOMO–LUMO gap of the fluorouracil···graphene molecule. Furthermore, the analysis of interaction of the 5-FU with graphene was carried out through the energy decomposition analysis (EDA). There were excellent linear relationships between electronic spatial extent (ESE), frontier orbital energies and energy of interaction with external electric field strength.

The symmetry breaking of molecules depends on its context and origin. It is well shown the pseudo Jahn – Teller effect (PJTE) describes the origin of symmetry breaking of planar configurations. Based on the PJTE theory, the configurations, electronic parameters and conformational changes in molecular systems are predicted. Optimization of the D2h and C2h configurations of tetrahalodigermene Ge2X4 (X = Cl, Br, I) by ab initio calculations showed that the C2h configurations are more stable than planar ones. The different energy between high-symmetry D2h geometries and low-symmetry C2h geometries decrease from Ge2Cl4 to Ge2I4. Instability of the high-symmetry D2h configurations is arising from the PJT coupling of the ground Ag state and the exited B2g state in the Qb2g direction. The PJTE problem $$({{A}_{g}} + {{B}_{{2g}}}) \otimes {{b}_{{2g}}}$$ creates stable geometries of Ge2X4 (X = Cl, Br, I) analogs with C2h configurations. It is expected that when the energy gap between the desired states with D2h configurations decreases, the PJT stabilization energy (EPJT) increases. Despite this expectation, with increasing the energy gap from Ge2Cl4 to Ge2I4, EPJT decreases. According to the results of the canonical molecular orbital (CMO) analysis, the contributions of the b3u and b1u molecular orbitals in the vibronic coupling constant (F) decrease from Ge2Cl4 to Ge2I4. Consequently, assuming the primary force constant is positive, the negative curvatures of ground state electronic configuration curves in adiabatic potential energy surfaces (APESs) decreases from Ge2Cl4 to Ge2I4. The trend observed for the variations of the chemical hardness (η) of Ge2X4 analogs obey the maximum hardness principle.

In this study, hydrolysis of the anticancer drug trans-bis-(3-amino-flavone)dichloridoplatinum(II) (trans- Pt(3-af)2Cl2; TCAP) in gas and solution phases is studied. With the polarizable continuum model (PCM) model the complex computational study is performed in an aqueous solvent. Before the complex interaction with the target biomolecules, two typical reactions involved in the complex hydrolysis include the first and second hydrolysis processes. Thermodynamic and kinetic parameters of the hydrolysis reactions are analyzed. The variations of two structural parameters of the reaction are discussed.

This study investigates the interaction between C20 and the cis-PtCl2(NH3)2 complex using MPW1PW91 quantum chemical calculations in gas and solution phases. Two interaction modes between C20 and the cis-PtCl2(NH3)2 complex are considered: I-isomer (η2-C20) and II-isomer (η1-C20). It also determines the effects of the solvent polarity on the dipole moment, electronic spatial extent (ESE), structural parameters, and frontier orbital energies of two possible isomers of the C20…cis-PtCl2(NH3)2 complex. The bonding interaction between C20 and the cis-PtCl2(NH3)2 complex was examined through energy decomposition analysis (EDA). The metal–ligand bonds are evaluated using the percentage composition of the specific groups of frontier orbitals. The quantum theory of atoms in molecules (QTAIM) analysis is applied to assess the Pt–C bonds within the complex. Finally, the Pt–C spin-spin coupling constants are calculated using the gauge independent atomic orbital (GIAO) method.

The effect of solvent on the structural, frontier orbital energies, global density-based descriptors, vibrational frequencies, and 31P NMR chemical shifts was examined for the syn-Cp2Ti(η2-C6H4-2-OMe)(PMe3) complex by the self-consistent reaction field theory (SCRF) based on the polarizable continuum model (PCM). The studied spectroscopic parameters were correlated with the Kirkwood–Bauer–Magat (KBM) equation. Also, the response of the global density-based descriptors (chemical potential and hardness) in the presence of external electric field was studied. EDA, QTAIM, ELF, LOL, and NBO analyses were used for illustration of the Ti–C bond in this complex.

The unique features of zinc oxide nanosheet (ZnONS) as an appropriate platform for Flutamide molecule was considered by means of density functional theory (DFT) framework with van der Waals (vdW) approximation via Perdew–Burke–Ernzerhof variant of the generalized gradient approximation (PBE-GGA) method along with double zeta polarization (DZP) basis set. The most stable model of interaction between Flutamide molecule and ZnONS is specified and adsorption energies (E ads) are assessed. In energetically favorable configuration, O atoms of –NO2 group of Flutamide interacts with a Zn atom of the ZnONS at 2.11 A with Eads of −20.616 kcal mol−1 . We have scrutinized charge analysis between species involved through famous Mulliken, Hirshfeld and Voronoi approaches. Furthermore, we have examined the density of states (DOS) and the projected density of states (PDOS) for the energetically favorable model to explore the interaction of the drug molecule with the ZnONS. Besides, quantum molecular descriptors (QMD) are also analyzed upon interaction of drug molecule on ZnONS. To deeper knowledge the details of the interaction between the Flutamide and the ZnONS, Quantum Theory of Atoms in Molecules (QTAIM) calculations are implemented. The values of ▽ 2 ρ(BCP) and H(BCP) for (Flutamide)O⋯Zn(ZnONS) at the most stable configuration are positive and G/|V| is greater than 1, it denotes the non-covalent interaction between Flutamide with ZnONS. The DFT calculation based on molecular dynamics (MD) approach are utilized to acquire a better understand into the nature of the Flutamide drug and ZnONS interactions. The MD outcomes demonstrate that when the Flutamide molecule takes longer time to link with ZnONS, the Flutamide/ZnONS complex becomes stable. Moreover, after Flutamide molecule adsorption phenomenon the electrical conductivity generates an electrical signal. The outcomes affirmed the potential of a ZnONS as a drug delivery system (DDS) for drug molecule to remedy cancer and may be an appropriate sensor for the Flutamide drug detection.

In this investigation, the structural, electronic, and spectroscopic properties of the anticancer active molecule, carboplatin, were investigated in gas and solution phases. Based on the polarizable continuum model (PCM), the solvent effect on the structural parameters, frontier orbital energies, and spectroscopic parameters of the complex were explored. The results specify that the solvent polarity plays a significant role in the properties of the complex. The calculated vibrational frequencies were employed to decide the types of molecular motions related with each of the experimental bands observed. The nonlinear optical properties of the complex reveal that changes induced in the solvents have a small effect on the hyperpolarizability.

In this article, the structural, electronic, and spectroscopic properties of osmabenzyne Os{≡CC(SiH3)=C(CH3)C(SiH3)=CH}Cl2(PH3)2 are explored in the gas phase and five solvents. The effects of solvents on the structural parameters, frontier orbital energies, and spectroscopic parameters of the complex are elucidated using the polarizable continuum model. The wavenumbers of selected IR-active vibrations in different solvents are obtained and correlated with the Kirkwood–Bauer–Magat equation. In addition, thermodynamic parameters of solvation are calculated for the complex. 1H and 13C NMR chemical shifts are estimated using the gauge-invariant atomic orbital method.

We report the results of theoretical mechanistic studies on PH3-assisted migration of a coordinated aryl group to a coordinated CO in the complexes RhCpI(CO) (p-XC6H4). The X-substituent effect on thermodynamic and kinetic parameters was explored. The progress of the reaction was quantitatively studied using the bond orders of the Rh-CO bond, and the percentages of bond cleavage (BCij) of Rh-CO bond at the transition state were described. This theoretical study indicates good relationships between barrier energy (ΔE), bond distances variations (Rh-CO and Rh-Ph), activation energy (ΔH‡) , activation free energy (ΔG‡) values with Hammett constants of X-substituents. Linear relationship between ln(k) and the 103Rh magnetic shielding tensors of the product was explored.

In this study, we report the substituent effect on the structures, frontier orbital analysis, and spectroscopic properties (IR, 13C, 29Si NMR) in the molybdenum silylidyne complexes CpMo(CO)2(≡Si-para-C6H4X) (X = H, F, Cl, CN, NO2 , Me, OMe, NH2 , NHMe) using MPW1PW91 quantum chemical calculations. The calculated structural parameters and spectral parameters are compatible with the experimental values in similar complexes. The nature of the chemical bond between the [Cp(OC) 2Mo]− and [Si-para-C6H4X]+ fragments was explored with energy decomposition analysis (EDA). The percentage composition in terms of the defined groups of frontier orbitals for CpMo(CO)2(≡Si-para-C6H4X) complexes was investigated to explore the character of the metal–ligand bonds. The linear correlations between the properties and Hammett constants (σ p) were illustrated. Natural bond orbital analysis (NBO) was used to illustrate the electronic structure of the complexes.

The structural, electronic, and spectroscopic properties of the anticancer active molecule of iproplatin were investigated in the gas and liquid phases. Based on the polarizable continuum model (PCM), the solvent effect on the structural parameters, frontier orbitals, and spectroscopic parameters of the complex was investigated. The results indicate that the polarity of solvents plays a significant role in the structure and pro perties of the complex. 1H and 13C NMR chemical shifts were calculated using the Gauge-invariant atomic orbital (GIAO) method. Pt–Cl and Pt–OH bonds were investigated through a vibrational analysis. Moreover, time dependent density functional theory (TD-DFT) was used to calculate the energy, oscillatory strength, and wavelength absorption maximum (λmax) of electronic transitions and its nature within the complex.

The present study illustrated the stability of linkage isomers of [Fe(CO)4(NCS)]− and [Fe(CO)4(SCN)]− by the use of PBE quantum method. It also investigated the polarity of solvent effect on dipole moment, structural parameters, and frontier orbital energies of complexes. The results indicated that the polarity of solvent had a significant effect on the frontier orbital energies and HOMO-LUMO gap. The character of Fe-C bonds of molecules was analyzed by Natural bond orbital (NBO) analysis. Back-bonding effect in these bonds was explored with calculation of quadrupole polarization of carbon atom by QTAIM analysis. Also, 14N NQR parameters were used for the illustration of Fe-NCS and Fe-SCN bonds.

First-principles van der Waals density functional (vdW-DF) calculation using GGA/PBE functional and DZP basis set implemented in the SIESTA package was carried out to investigation the encapsulation of penicillamine drug into the both armchair and zigzag single wall carbon nanotubes (SWCNTs). The results reveal that the drug encapsulated inside the CNT cavity is weakly bounded. The obtained results of binding energies indicated that incorporation of drug is favored inside the zigzag SWCNTs compared with armchair counterparts. We address here the role of vdW interaction for penicillamine drug when inclusion in the CNTs. It worth mentioning that encapsulation of vdW forces can be effects on the binding properties. The electronic structures and Mulliken charge population are analysed for the energetically most favorable complexes which shows that encapsulated penicillamine changes slightly the electronic properties of SWCNTs and trivial charges are transferred from drug to CNTs during encapsulation process. Global reactivity descriptor values such as electronegativity ( χ ), global hardness ( η ), global softness (S), electronic chemical potential ( μ ), and electrophilicity index ( ω ) were calculated. We anticipated that these findings supply the new way and value information for help in the experimental study and future applications.

The modified Perdew-Wang exchange and correlation method (MPW1PW91) is used to analyze the impact of the external electric field on the total energy, dipole moment, energies of frontier orbitals, HOMO—LUMO gaps, electron affinity, ionization potential, and aromaticity of the C5H5Ir(PH3)3 complex. We explore the percentage compositions of frontier orbitals in terms of the defined groups in the presence and absence of the external electric field. Additionally, a dependence of the global reactivity descriptors on the electric field strength is inspected. The aromaticity of the complex is analyzed by nucleus independent chemical shift values in the presence and absence of the external electric field.