Homolytic bond-dissociation enthalpies of tin bonds and tin–ligand bond strengths — A computational study

2009 ◽  
Vol 87 (7) ◽  
pp. 974-983 ◽  
Author(s):  
Sarah R. Whittleton ◽  
Russell J. Boyd ◽  
T. Bruce Grindley
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Basis Set ◽  
Functional Theory ◽  
Bond Dissociation ◽  
Donor Acceptor ◽  
Bond Strengths ◽  
Moller Plesset ◽  
Effective Core Potentials ◽  
Ligand Bond

Density functional theory and second-order Møller–Plesset perturbation theory with effective core potentials have been used to calculate homolytic bond-dissociation enthalpies, D(Sn–X), of organotin compounds, and their performance has been assessed by comparison with available experimental bond enthalpies. The SDB-aug-cc-pVTZ basis set with its effective core potential was used to calculate the D(Sn–X) of a series of trimethyltin(IV) species, Me3Sn–X, where X = H, CH3, CH2CH3, NH2, OH, Cl, and F. This is the most comprehensive report to date of homolytic Sn–X bond-dissociation enthalpies (BDEs). Effective core potentials are then used to calculate thermodynamic parameters including donor–acceptor bond enthalpies, [Formula: see text], for a series of tin-ligand complexes, L2SnX4 (X = Br or Cl, L = py, dmf, or dmtf), which are compared with previous experimental and nonrelativistic computational results. Based on computational efficiency and accuracy, it is concluded that effective core potentials are appropriate computational methods to examine bonding in organotin systems.

scholarly journals Density Functional Theory and Complete Basis Set Ab Initio Computational Study of Five-, Six-, Seven- and Eight-hydrogen Coordinated Carbon Cations

1999 ◽  
Vol 23 (8) ◽  
pp. 502-503
Author(s):  
Branko S. Jursic
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Computational Study ◽  
Basis Set ◽  
Functional Theory ◽  
Complete Basis ◽  
Complete Basis Set ◽  
High Level

High level ab initio and density functional theory studies are performed on highly protonated methane species.

Computational study of polarizability anisotropies

2018 ◽  
Vol 96 (10) ◽  
pp. 934-938
Author(s):  
Delano P. Chong
Keyword(s):  
Small Molecules ◽  
Density Functional ◽  
Computational Study ◽  
Chem Phys ◽  
Basis Set ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Exchange Correlation Potential ◽  
Correlation Potential ◽  
Definition Of

The dipole polarizabilities (α) and polarizability anisotropies (Δα) of over 20 molecules are calculated to search for negative Δα. The geometry of each molecule is first optimized at the level of CCSD(T)/cc-pVQZ. Then, the α tensors are computed both with CCSD(T)/daug-cc-pVTZ in Gaussian 09 and with the exchange-correlation potential Vxc known as SAOP in the Amsterdam density functional theory program called ADF and a large basis set called QZ3P-3DIFFUSE. In addition to the popular formula of the ΔαRaman connected with Raman spectroscopy, we also present values of an alternative definition of the polarizability anisotropy ΔαKerr connected with Kerr spectroscopy, recently proposed by Kampfrath and colleagues (2018. Chem. Phys. Lett. 692: 319). On one hand, the signs of many ΔαRaman are undetermined; on the other hand, we obtain negative ΔαKerr for more than one-half of the small molecules studied. Of the 24 molecules studied, 18 have negative ΔαKerr.

THEORETICAL STUDIES ON BOND DISSOCIATION ENERGIES FOR SOME THIOL COMPOUNDS BY DENSITRY FUNCTIONAL THEORY AND CBS-Q METHOD

2008 ◽  
Vol 07 (05) ◽  
pp. 943-951 ◽  
Author(s):  
XIAO-HONG LI ◽  
ZHENG-XIN TANG ◽  
ABRAHAM F. JALBOUT ◽  
XIAN-ZHOU ZHANG ◽  
XIN-LU CHENG
Keyword(s):  
Density Functional ◽  
Computational Cost ◽  
Basis Set ◽  
Basis Sets ◽  
Q Method ◽  
Bond Dissociation Energies ◽  
Functional Theory ◽  
Thiol Compounds ◽  
Bond Dissociation ◽  
Dissociation Energies

Quantum chemical calculations are used to estimate the bond dissociation energies (BDEs) for 15 thiol compounds. These compounds are studied by employing the hybrid density functional theory (B3LYP, B3PW91, B3P86, PBE0) methods and the complete basis set (CBS-Q) method together with 6-311G** basis set. It is demonstrated that B3P86 and CBS-Q methods are accurate for computing the reliable BDEs for thiol compounds. In order to test whether the non-local BLYP method suggested by Fu et al.19 is general for our study and whether B3P86 method has a low basis set sensitivity, the BDEs for seven thiol compounds are also calculated using BLYP/6-31+G* and B3P86 method with 6-31+G*, 6-31+G**, and 6-311+G** basis sets for comparison. The obtained results are compared with the available experimental results. It is noted that B3P86 method is not sensitive to the basis set. Considering the inevitable computational cost of CBS-Q method and the reliability of the B3P86 calculations, B3P86 method with a moderate or a larger basis set may be more suitable to calculate the BDEs of the C–SH bond for thiol compounds.

scholarly journals Protonated heterocyclic derivatives of cyclopropane and cyclopropanone: classical species, alternate sites, and ring fragmentation

2015 ◽  
Vol 93 (7) ◽  
pp. 708-714 ◽  
Author(s):  
Margarida S. Miranda ◽  
Darío J.R. Duarte ◽  
Joaquim C.G. Esteves da Silva ◽  
Joel F. Liebman
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Density Functional ◽  
Computational Study ◽  
Basis Set ◽  
Proton Affinities ◽  
Functional Theory ◽  
Heterocyclic Derivatives ◽  
Gas Phase Basicities ◽  
Derivatives Of

A computational study has been performed for protonated oxygen- or nitrogen-containing heterocyclic derivatives of cyclopropane and cyclopropanone. We have searched for the most stable conformations of the protonated species using density functional theory with the B3LYP functional and the 6-31G(2df,p) basis set. More accurate enthalpy values were obtained from G4 calculations. Proton affinities and gas-phase basicities were accordingly derived.

scholarly journals Halogen Interactions in Halogenated Oxindoles: Crystallographic and Computational Investigations of Intermolecular Interactions

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5487
Author(s):  
Rodrigo A. Lemos Silva ◽  
Demetrio A. da Silva Filho ◽  
Megan E. Moberg ◽  
Ted M. Pappenfus ◽  
Daron E. Janzen
Keyword(s):  
Interaction Energy ◽  
Intermolecular Interactions ◽  
Density Functional ◽  
Basis Set ◽  
Interaction Energies ◽  
Functional Theory ◽  
Basis Set Superposition Error ◽  
Reduced Density Gradient ◽  
Moller Plesset ◽  
Reduced Density

X-ray structural determinations and computational studies were used to investigate halogen interactions in two halogenated oxindoles. Comparative analyses of the interaction energy and the interaction properties were carried out for Br···Br, C-H···Br, C-H···O and N-H···O interactions. Employing Møller–Plesset second-order perturbation theory (MP2) and density functional theory (DFT), the basis set superposition error (BSSE) corrected interaction energy (Eint(BSSE)) was determined using a supramolecular approach. The Eint(BSSE) results were compared with interaction energies obtained by Quantum Theory of Atoms in Molecules (QTAIM)-based methods. Reduced Density Gradient (RDG), QTAIM and Natural bond orbital (NBO) calculations provided insight into possible pathways for the intermolecular interactions examined. Comparative analysis employing the electron density at the bond critical points (BCP) and molecular electrostatic potential (MEP) showed that the interaction energies and the relative orientations of the monomers in the dimers may in part be understood in light of charge redistribution in these two compounds.

scholarly journals Structural characterization of kaempferol: a spectroscopic and computational study

2019 ◽  
Vol 38 (1) ◽  
pp. 49 ◽  
Author(s):  
Dejan Milenković ◽  
Jasmina M Dimitrić Marković ◽  
Dušan Dimić ◽  
Svetlana Jeremić ◽  
Dragan Amić ◽  
...  
Keyword(s):  
Density Functional ◽  
Computational Study ◽  
Chemical Shifts ◽  
Absolute Error ◽  
Nbo Analysis ◽  
Basis Set ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Spectroscopic Characteristics

Calculations based on the density functional theory, with the B3LYP functional and the 6-311++G(d,p) basis set, were performed with the aim of confirming the molecular structure and spectroscopic characteristics of kaempferol, a naturally occurring flavonoid molecule. The electronic structure of kaempferol was examined using NBO analysis. The assigning of the experimentally obtained IR and Raman spectra was performed after the best-fit-based comparison with theoretical spectra. The 13C and 1H NMR experimental spectra were related to the theoretically obtained values of the chemical shifts determined by the GIAO method. The correlation coefficient and the average absolute error values proved B3LYP-D3 to be an adequate method in describing the NMR parameters of kaempferol. Molecular docking analysis was carried out in order to identify the potency of inhibition of the title molecule against human procalcitonin. The inhibition activity was obtained for 10 conformations of ligand inside the protein.

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