scholarly journals Beryllium (II) Chloride Complexes with Phosphoryl Ligands: A DFT Study

2021 ◽  
pp. 38-46
Author(s):  
K. Essalah ◽  
M. A. K. Sanhoury ◽  
M. T. Ben Dhia ◽  
M. R. Khaddar
Keyword(s):  
Structural Changes ◽  
Chemical Shifts ◽  
Geometry Optimization ◽  
Theoretical Data ◽  
Binding Energies ◽  
Basis Set ◽  
Chloride Complexes ◽  
Beryllium Complexes ◽  
Chemical Shift Calculations ◽  
Good Agreement

Beryllium complexes of the types [BeCl2L2] (L = (Me2N)3P(O) (1), (Me2N)2P(O)F (2), Me2NP(O)F2 (3) and P(O)F3 (4)) have been theoretically studied by means of DFT geometry optimization and NMR chemical shift calculations (B3LYP/6-31G(d)). A good correlation was found between calculated and experimental data for complex 2. On going from complex 1 to 4, the Be-L bond underwent considerable lengthening, while that of Be-Cl was shortened (Be-O: 1.646 in 1 vs. 1.740 A° in 4; Be-Cl: 2.043 in 1 vs. 1.953 A° in 4). In the same way, the Be-O-P bond angle was found to decrease from 135° for 1 to 124° for 4. The trends are in good agreement with the calculated metal-ligand binding energies of complexes 1-4. Interestingly, the structural changes are accompanied by increased 9Be chemical shifts towards higher frequencies as the Me2N groups in the ligand are substituted by fluorine atoms. The results were compared to corresponding complexes with tin (IV) chloride, [SnCl4L2]. The theoretical data showed that the use of the 6-31G* basis set could efficiently predict the 9Be NMR chemical shifts in the complexes [BeCl2L2].

scholarly journals Geometric and energetic data from quantum chemical calculations of halobenzenes and xylenes

2020 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Software Package ◽  
Geometry Optimization ◽  
Theoretical Data ◽  
Basis Set ◽  
Chemical Calculation ◽  
Custom Made

<p>This article presents theoretical data on geometric and energetic features of halobenzenes and xylenes. Data were obtained from <i>ab initio</i> geometry optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. In total, 1504 structures of halobenzenes, three structures of xylenes and one structure of benzene were generated and processed by custom-made codes in Mathematica. The quantum chemical calculation was completed in Q-Chem software package. Geometric and energetic data of the compounds are presented in this paper as supplementary tables. Raw output files as well as codes and scripts associated with production and extraction of data are also provided.</p>

A density functional approach toward structural features and properties of C20…N2X2 (X = H, F, Cl, Br, Me) molecules

2014 ◽  
Vol 13 (04) ◽  
pp. 1450023 ◽  
Author(s):  
Reza Ghiasi ◽  
Morteza Zaman Fashami ◽  
Amir Hossein Hakimioun
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Geometry Optimization ◽  
Structural Features ◽  
Nbo Analysis ◽  
Basis Set ◽  
Basis Sets ◽  
Basis Set Superposition Error ◽  
Homo And Lumo ◽  
Lowest Unoccupied Molecular Orbitals

In this work, the interaction of C 20 with N 2 X 2 ( X = H , F , Cl , Br , Me ) molecules has been explored using the B3LYP, M062x methods and 6-311G(d,p) and 6-311+G(d,p) basis sets. The interaction energies (IEs) obtained with standard method were corrected by basis set superposition error (BSSE) during the geometry optimization for all molecules at the same levels of theory. It was found C 20… N 2 H 2 interaction is stronger than the interaction of other N 2 X 2 ( X = F , Cl , Br , Me ) with C 20. Highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO, respectively) levels are illustrated by density of states spectra (DOS). The nucleus-independent chemical shifts (NICSs) confirm that C 20… N 2 X 2 molecules exhibit aromatic characteristics. Geometries obtained from DFT calculations were used to perform NBO analysis. Also, 14 N NQR parameters of the C 20… N 2 X 2 molecules are predicted.

scholarly journals Geometric and Energetic Data from Quantum Chemical Calculations of Halobenzenes and Xylenes

2020 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Software Package ◽  
Geometry Optimization ◽  
Theoretical Data ◽  
Basis Set ◽  
Chemical Calculation ◽  
Custom Made

<div>This article presents theoretical data on geometric and energetic features of halobenzenes and xylenes. Data were obtained from ab initio geometry optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. In total, 1504 structures of halobenzenes, three structures of xylenes and one structure of benzene were generated and processed by custom-made codes in Mathematica. The quantum chemical calculation was completed in Q-Chem software package. Geometric and energetic data of the compounds are presented in this paper as supplementary tables. Raw output files as well as codes and scripts associated with production and extraction of data are also provided.</div>

scholarly journals Geometric and energetic data from quantum chemical calculations of halobenzenes and xylenes

2020 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Software Package ◽  
Geometry Optimization ◽  
Theoretical Data ◽  
Basis Set ◽  
Chemical Calculation ◽  
Custom Made

<p>This article presents theoretical data on geometric and energetic features of halobenzenes and xylenes. Data were obtained from <i>ab initio</i> geometry optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. In total, 1504 structures of halobenzenes, three structures of xylenes and one structure of benzene were generated and processed by custom-made codes in Mathematica. The quantum chemical calculation was completed in Q-Chem software package. Geometric and energetic data of the compounds are presented in this paper as supplementary tables. Raw output files as well as codes and scripts associated with production and extraction of data are also provided.</p>

X-ray photoelectron spectroscopic (XPS) studies of iodine oxocompounds

1988 ◽  
Vol 53 (3) ◽  
pp. 425-432 ◽  
Author(s):  
Zdeněk Bastl ◽  
Heidrun Gehlmann
Keyword(s):  
Cross Sections ◽  
Chemical Shifts ◽  
Theoretical Data ◽  
Binding Energies ◽  
Oxidation States ◽  
Core Electron ◽  
X Ray ◽  
The Core ◽  
Quantitative Surface Analysis ◽  
Electron Binding Energies

The core electron binding energies of eighteen compounds containing iodine in different oxidation states ranging from (-I) to (VII) have been measured. The observed chemical shifts differ from the literature data. The anticipated existence of hexavalent iodine in certain compounds has not been demonstrated. The relative subshell photoemission intensities of iodine have been determined. Empirically derived atomic sensitivity factors and theoretical photoionization cross-sections have been used to calculate the surface stoichiometry. The concentration ratios obtained via the two methods are compared. In agreement with generally accepted view the results of this comparison imply that, for quantitative surface analysis, empirical values should be used rather than theoretical data.

scholarly journals Geometric and Energetic Data from Quantum Chemical Calculations of Halobenzenes and Xylenes

2019 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb
Keyword(s):  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Software Package ◽  
Geometry Optimization ◽  
Theoretical Data ◽  
Basis Set ◽  
Chemical Calculation ◽  
Custom Made

<div>This article presents theoretical data on geometric and</div><div>energetic features of halobenzenes and xylenes. Data were obtained from ab initio geometry optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. In total, 1504 structures of halobenzenes, three structures of xylenes and one structure</div><div>of benzene were generated and processed by custom-made codes in Mathematica. The quantum chemical calculation was completed in Q-Chem software package. Geometric and energetic data of the compounds are presented in this paper as supplementary tables. Raw output files as well as codes and scripts associated with production and extraction of data are also provided.</div>

Abinitio Calculations of the Barriers to Rotation in Some Monosubstituted Benzenes

1986 ◽  
Vol 39 (7) ◽  
pp. 1157 ◽  
Author(s):  
S Marriott ◽  
RD Topsom
Keyword(s):  
Electron Transfer ◽  
Ab Initio ◽  
Benzene Ring ◽  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Basis Set ◽  
Monosubstituted Benzenes ◽  
Split Valence ◽  
Good Agreement ◽  
Abinitio Calculations

Theoretical calculations at the ab initio level have been made of the twofold rotational barriers of some monosubstituted benzenes, and the effects both of basis set and of geometry optimization have been examined. Values at the STO-3G//STO-3G level are in good agreement with experiment. The use of split-valence sets, even with geometry optimization, is much less satisfactory, and this may be related to an overestimation of π-electron transfer between the substituent and the benzene ring.

Revisiting B20H16 by means of a joint computational/experimental NMR approach

2010 ◽  
Vol 75 (11) ◽  
pp. 1115-1123 ◽  
Author(s):  
Drahomír Hnyk ◽  
Josef Holub ◽  
Tomáš Jelínek ◽  
Jan Macháček ◽  
Michael G. S. Londesborough
Keyword(s):  
Solid State ◽  
Chemical Shifts ◽  
Molecular Geometry ◽  
Basis Set ◽  
State Structure ◽  
Solid State Structure ◽  
Boron Cluster ◽  
Nmr Study ◽  
New Synthesis ◽  
Good Agreement

A new synthesis of the fused macropolyhedral boron cluster B20H16 is described and its molecular structure in solution discussed, based on multi-nuclear NMR spectra, including COSY measurements, in relation to its previously elucidated solid-state structure. To verify the conclusions from the NMR study, experimentally determined chemical shifts are compared with calculated values at the GIAO-B3LYP level with a TZP basis set by Huzinaga. There is a very good agreement between the experimental and computed δ(11B) values, suggesting that the MP2/6-31G* internal coordinates are a reasonable representation of the molecular geometry of this twenty-vertex cluster in solution that is essentially the same as its solid-state structure. A computational analysis of the FMO orbitals of B20H16, in particular of the LUMO, reveals that the four naked boron atoms, common for two shared icosahedral subclusters, are the reactive sites of this D2d-symmetrical molecule.

A CASSCF/CASPT2 STUDY ON THE LOW-LYING ELECTRONIC STATES OF THE (CH3)2CHS AND ITS CATION

2013 ◽  
Vol 12 (06) ◽  
pp. 1350047
Author(s):  
FAN-XIA WANG ◽  
ZENG-XIA ZHAO ◽  
HONG-XING ZHANG
Keyword(s):  
Ground State ◽  
Spectroscopic Data ◽  
Geometry Optimization ◽  
Electronic States ◽  
Vibrational Frequencies ◽  
Geometric Parameters ◽  
Basis Set ◽  
Natural Orbital ◽  
Atomic Natural Orbital ◽  
Good Agreement

The multireference approach (CASSCF/CASPT2) combined with the contracted with atomic natural orbital (ANO-RCC-VTZP) basis set has been used to investigate systematically, the low-lying electronic states of ( CH 3)2 CHS in Cs symmetry. The result of geometry optimization using CASSCF/ANO-RCC-VTZP shows that the theoretically determined geometric parameters and harmonic vibrational frequencies for the ground state X2A′ of ( CH 3)2 CHS are in good agreement with previous studies. In addition, we also explored several cationic states adiabatically and found that the 11A′ state of ( CH 3)2 CHS + is unstable and converts to ( CH 3)2 CSH +. The vertical and adiabatic ionization energies were obtained to compare with photoelectron spectroscopic data.

scholarly journals COMPUTATIONAL INVESTIGATION ON THE STRUCTURE AND NMR CHEMICAL SHIFTS OF ENDO-CONE [CS2(p-METHYLCALIX[4]ARENE)] COMPLEX

2010 ◽  
Vol 9 (2) ◽  
pp. 289-291
Author(s):  
Hanggara Sudrajat ◽  
Muhammad S. Saefullah ◽  
Danis Sriwijaya ◽  
Mirta A. Putri ◽  
Ria Armunanto
Keyword(s):  
Solid State ◽  
Ab Initio ◽  
Chemical Shifts ◽  
Computational Investigation ◽  
Nmr Chemical Shifts ◽  
Nmr Data ◽  
Arene Complex ◽  
Semi Empirical ◽  
Chemical Shift Calculations ◽  
Good Agreement

The structure and NMR chemical shifts of endo-cone [CS2(p-methylcalix[4]arene)] complex have been computationally investigated using BIO+ force fields, semi-empirical (PM3) and ab initio (RHF/6-311G++(d,p)) calculations. The first comparison of ab initio NMR chemical shift calculations for a calix[4]arene inclusion complex with solid-state 13C NMR chemical shifts based on the 1:1 complex of p-methylcalix[4]arenes with carbon disulfide in endo-cone complexation mode has been reported. The results showed that ab initio (RHF/6-311G++(d,p)) NMR calculations of the host-guest [CS2(p-methylcalix[4]arene)] complex are in good agreement with experimental solid-state NMR data.    Keywords: computational investigation, structure, NMR chemical shifts, [CS2(p-methylcalix[4]arene)].

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