The effect of the functional, basis set, and solvent in the simulation of the geometry and spectroscopic properties of VIV O2+ complexes. chemical and biological applications

2011 ◽  
Vol 112 (12) ◽  
pp. 2486-2498 ◽  
Author(s):  
Giovanni Micera ◽  
Eugenio Garribba
Keyword(s):  
Spectroscopic Properties ◽  
Basis Set ◽  
Biological Applications ◽  
Functional Basis

scholarly journals Molecular Hydrogen as a Lewis Base in Hydrogen Bonds and Other Interactions

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3294 ◽  
Author(s):  
Sławomir J. Grabowski
Keyword(s):  
Hydrogen Bonds ◽  
Molecular Hydrogen ◽  
Spectroscopic Properties ◽  
Lewis Base ◽  
Basis Set ◽  
Orbital Method ◽  
Topological Parameters ◽  
Theoretical Approaches ◽  
Strength Of Interaction ◽  
Moller Plesset

The second-order Møller–Plesset perturbation theory calculations with the aug-cc-pVTZ basis set were performed for complexes of molecular hydrogen. These complexes are connected by various types of interactions, the hydrogen bonds and halogen bonds are most often represented in the sample of species analysed; most interactions can be classified as σ-hole and π-hole bonds. Different theoretical approaches were applied to describe these interactions: Quantum Theory of ‘Atoms in Molecules’, Natural Bond Orbital method, or the decomposition of the energy of interaction. The energetic, geometrical, and topological parameters are analysed and spectroscopic properties are discussed. The stretching frequency of the H-H bond of molecular hydrogen involved in intermolecular interactions is considered as a parameter expressing the strength of interaction.

scholarly journals The Spectroscopic and Conductive Properties of Ru(II) Complexes with Potential Anticancer Properties

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Adebayo A. Adeniyi ◽  
Peter A. Ajibade
Keyword(s):  
Density Functional ◽  
Spectroscopic Properties ◽  
Spin Coupling ◽  
Basis Set ◽  
Polarizability Tensor ◽  
Chemical Hardness ◽  
Anticancer Properties ◽  
Shielding Tensor ◽  
Spin Spin Coupling ◽  
Conductive Properties

Different density functional methods (DFT) have been used to optimize and study the chemistry of five potential anticancer complexes in terms of their electronic, conductive, and spectroscopic properties. Many of the computed properties in addition to the IR and QTAIM analysis of the NMR are dipole moment vector (μi), linear polarizability tensor (αij), first hyperpolarizability tensors (βijk), polarizability exaltation index (Γ), and chemical hardness (η) of the complexes. Stable low energy geometries are obtained using basis set with effective core potential (ECP) approximation but, in the computation of atomic or molecular properties, the metal Ru atom is better treated with higher all electron basis set like DGDZVP. The spectroscopic features like the IR of the metal-ligand bonds and the isotropic NMR shielding tensor of the coordinated atoms are significantly influenced by the chemical environment of the participating atoms. The carboxylic and pyrazole units are found to significantly enhance the polarizabilities and hyperpolarizabilities of the complexes while the chloride only improves the polarity of the complexes. Fermi contacts (FC) have the highest effect followed by the PSO among all the four Ramsey terms which defined the total spin-spin coupling constant J (HZ) of these complexes.

Density Functional Study of the Electronic Structure and Related Properties of Pt(NO)/Pt(NO2) Redox Couples

2003 ◽  
Vol 68 (3) ◽  
pp. 423-446 ◽  
Author(s):  
Paraskevas Karipidis ◽  
Athanassios C. Tsipis ◽  
Constantinos A. Tsipis
Keyword(s):  
Ground State ◽  
Density Functional ◽  
Activation Barrier ◽  
Spectroscopic Properties ◽  
Redox Couple ◽  
Basis Set ◽  
Stationary Points ◽  
Functional Study ◽  
Dft Theory ◽  
Exothermic Process

Density functional calculations at the B3LYP level of theory, using the SDD basis set, provide satisfactory description of geometric, energetic, electronic and spectroscopic properties of the Pt(NO)/Pt(NO2) redox couple. The neutral Pt(NO) species adopts a bent 2A' ground state, while the cationic [Pt(NO)]+ species adopts a linear 1Σ+ ground state. The B3LYP/SDD- predicted Pt-N bond lengths are 2.016 and 1.777 Å for Pt(NO) (2A') and [Pt(NO)]+ (1Σ+), respectively, while the ∠Pt-N-O bent angle for [Pt(NO)] (2A') is 119.6°. On the other hand, the anionic [Pt(NO)]- species adopts the bent 1A' ground state with a Pt-N bond length of 1.867 Å and a ∠Pt-N-O bent angle of 122.5°. The computed binding energies of the NO, NO+ and NO- ligands with Pt(0) were found to be 29.9 (32.8), 69.9 (78.4) and 127.4 (128.7) kcal/mol at the B3LYP/SDD and CCSD(T)/SDD (numbers in parentheses) levels of theory, respectively. Moreover, the structure of the [Pt(NO2)]+ component of the Pt(NO)/Pt(NO2) redox couple and its transformation to [Pt(NO)]+ upon reaction with CO was analysed in the framework of the DFT theory. The coordination of the CO ligand to [Pt(NO2)]+ affords the cationic mixed-ligand [Pt(CO)(NO2)]+ complex, which is stabilized by 66.6 (60.5) kcal/mol, with respect to the separated [Pt(NO2)]+ and CO in their ground states. The O-transfer reaction from the coordinated NO2 to the coordinated CO ligands in the presence of the [Pt(NO2)]+ species corresponds to an exothermic process; the heat of the reaction (∆RH) is -85.2 (-80.5) kcal/mol and the activation barrier amounts to 27.7 (33.0) kcal/mol. Finally, the equilibrium structures of selected stationary points related to the transformation of NO to NO2 ligand located on the potential energy surfaces of the [Pt(NO),O2], [Pt(NO)+,O2], and [Pt(NO)-,O2] systems were analysed in the framework of the DFT theory. The computed interaction energies of O2 with Pt(NO), [Pt(NO)]+ and [Pt(NO)]- species were found to be 106.9 (105.3), 49.2 (48.4) and 26.9 (26.5) kcal/mol, respectively. The O2 ligand is coordinated to the Pt central atom in an end-on mode for [Pt(NO),O2] and [Pt(NO)-,O2] systems and in a side-on mode for the [Pt(NO)+,O2] system. The transformation of NO to NO2 in [Pt(NO)]- species upon reaction with dioxygen corresponds to an exothermic process; the heat of the reaction (∆RH) is -60.6 (-55.8) kcal/mol, while the activation barrier amounts to 35.5 (30.2) kcal/mol. Calculated structures, relative stability and bonding properties of all stationary points are discussed with respect to computed electronic and spectroscopic properties, such as charge density distribution and harmonic vibrational frequencies.

scholarly journals DFT and TD-DFT Study of Structure and Properties of Semiconductive Hybrid Networks Formed by Bismuth Halides and Different Polycyclic Aromatic Ligands

2011 ◽  
Vol 8 (s1) ◽  
pp. S195-S202
Author(s):  
Y. Belhocine ◽  
M. Bencharif
Keyword(s):  
Density Functional Theory ◽  
Band Gap ◽  
Density Functional ◽  
Relativistic Effects ◽  
Spectroscopic Properties ◽  
Basis Set ◽  
Dft Methods ◽  
Functional Theory ◽  
Td Dft ◽  
Polycyclic Aromatic

The structure and spectroscopic properties of polycyclic aromatic ligands of 2,3,6,7,10,11-hexakis (alkylthio) triphenylene (alkyl: methyl, ethyl, and isopropyl; corresponding to the abbreviations of the molecules: HMTT, HETT and HiPTT) were studied using density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods with triple-zeta valence polarization (TZVP) basis set. It was shown that the type of functional theory used, Becke-Perdew (BP) and Leeuwen-Baerends (LB94) implemented in Amsterdam Density functional (ADF) program package, does not have essential influence on the geometry of studied compounds in both ground and excited states. However, significant differences were obtained for the band gap values with relativistic effects of the zero order regular approximation scalar corrections (ZORA) and LB94 functional seems to reproduce better the experimental optical band gap of these systems.

Synthesis, Spectroscopic Properties, and Biological Applications of Eight Novel Chlorinated Fluorescent Proteins-labeling Probes

2014 ◽  
Vol 24 (3) ◽  
pp. 775-786
Author(s):  
Xianglong Wu ◽  
Min Tian ◽  
Wutu Fan ◽  
Yalei Pan ◽  
Yuankun Zhai ◽  
...  
Keyword(s):  
Fluorescent Proteins ◽  
Spectroscopic Properties ◽  
Biological Applications

Theoretical Studies on the Structure and Spectroscopic Properties of 2,4-D (2,4-Diclorofenoxiacetic Acid)

2012 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
María G. Andino ◽  
Mariela I. Profeta ◽  
Jorge M. Romero ◽  
Nelly L. Jorge ◽  
Eduardo A. Castro
Keyword(s):  
Density Functional ◽  
Theoretical Calculations ◽  
Spectroscopic Properties ◽  
Uv Spectra ◽  
Basis Set ◽  
Basis Sets ◽  
Electronic Effects ◽  
B3lyp Method ◽  
Molecular Stability ◽  
2,4 Dichlorophenoxyacetic Acid

The 2,4-dichlorophenoxyacetic acid (2,4-D) is applied to and recovered from the leaf surfaces of garden bean and corn plants. This paper examines the theoretical study of the 2,4-D IR and UV spectra as well as the determination of its optimized molecular structure. Theoretical calculations are performed at the density functional theory (DFT) levels. The different structural and electronic effects determining the molecular stability of the conformers are discussed in a comparative fashion. The optimized geometry was calculated via the B3LYP method with 6-311G(d,p) and 6-311++G(d,p) basis sets and the FT-IR spectra was calculated by the density functional B3LYP method with the 6-311++G(d,p) basis set. The scaled theoretical wavenumbers show good agreement with the experimental values. A detailed interpretation of the infrared spectra of 2,4-D is reported.

scholarly journals Spectral characteristics and DFT Study of vanadyl octaethylporphyrin complex

2019 ◽  
Vol 8 (2) ◽  
pp. 132
Author(s):  
Hamza EL HADKI ◽  
Mohammed Salah ◽  
Abdallah Zrineh ◽  
Khadija Marakchi ◽  
Hassna Abou El Makarim ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Reactivity ◽  
Spectral Characteristics ◽  
Spectroscopic Properties ◽  
Basis Set ◽  
Hybrid Functional ◽  
Functional Theory ◽  
Density Analysis ◽  
Electron Density Analysis ◽  
Made In

<p>The chemistry of vanadyl porphyrins has been explored using vanadyl octaethylporphyrin as a substance in petroleum porphyrins, crude oils and bitumen. The structural, electronic, thermodynamic, spectroscopic properties are described. The geometry’s optimization of this molecule was done by Density Functional Theory (DFT) using the hybrid Beck three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional (B3LYP) and 6-31G(d) standard basis set. All calculations have been made in the gas phase and in different solvents: benzene, benzonitrile, tetrachloromethane and chloroform. The calculated infrared spectrum was compared with experimental spectroscopic data, and the vibrational assignment was provided. An electron density analysis in terms of natural bond orbitals was conducted to determine the nature of the bonds between the vanadium and nitrogen atoms. The spatial representation of the associated molecular orbitals helped to explain the formation of the V-N bonds and to interpret the chemical reactivity of the compound studied. The electrostatic potential was calculated in order to investigate the reaction properties of the molecule.<strong></strong></p>

scholarly journals CONFORMATIONAL EQUILIBRIUM AND SPECTROSCOPIC PROPERTIES OF CALIX[4]ARENE: THEORETICAL STUDY USING AB INITIO METHOD

2010 ◽  
Vol 8 (3) ◽  
pp. 397-403 ◽  
Author(s):  
Hanggara Sudrajat ◽  
Ria Armunanto
Keyword(s):  
Ab Initio ◽  
Conformational Equilibrium ◽  
Spectroscopic Properties ◽  
Molecular Structures ◽  
Basis Set ◽  
Basis Sets ◽  
Molecular Orbital Calculations ◽  
Stable Conformer ◽  
Hartree Fock ◽  
Partial Cone

Molecular structures were optimized for the calix[4]arene by ab initio method at the Hartree-Fock level of theory using LANL2DZ and 6-311G basis sets. Conformational equilibrium of four calix[4]arene conformers are reported. The results are compared with experiment, force field, and semiempirical molecular orbital calculations. General trends in relative stabilities of calix[4]arene decrease in following order: cone > partial-cone > 1,2-alternate > 1,3-alternate. The most stable conformer is the cone conformer that is stabilized by an array of four hydrogen bonds and these results agree with the reported experimental observations. All structures were analyzed using theoretical IR, UV-Vis, and 1H NMR spectra attributed to the conformational equilibrium at the Hartree-Fock level of theory using LANL2DZ basis set.     Keywords: ab initio calculation, calix[4]arene, conformations, cone

scholarly journals Comparative experimental and theoretical study on the molecular structure and spectroscopic properties of sideroxol isolated from Sideritis stricta and its electronic properties

2021 ◽  
Vol 9 (2) ◽  
pp. 94-107
Author(s):  
Akin Azizoglu ◽  
◽  
Zuleyha Ozer ◽  
Carikci Sema ◽  
Turgut Kilic ◽  
...  
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Chemical Shifts ◽  
Molecular Geometry ◽  
Spectroscopic Properties ◽  
Basis Set ◽  
Basis Sets ◽  
Polarization Functions ◽  
Nmr Properties ◽  
Theory And Experiments

Sideroxol, a kaurene diterpene, was obtained from the acetone extract of Sideritis stricta plant. The ground-state molecular geometry, vibrational frequencies, and NMR chemical shifts were also investigated by using various density functional theories and Pople basis sets. The computed geometries are in good conformity with the experimental data. The comparison between theory and experiments indicates that B3LYP and M06 methods with the 6-31G(d) basis set are able to provide satisfactory results for predicting vibrational and NMR properties. There seems to be no significant effect of addition of diffuse and polarization functions in the basis set used herein.

Sign in / Sign up

Export Citation Format

Share Document