scholarly journals Dual XH–π Interaction of Hexafluoroisopropanol with Arenes

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4558
Author(s):  
Le Lu ◽  
Ruimao Hua
Keyword(s):  
Hydrogen Bond ◽  
Interaction Energy ◽  
Correlation Energy ◽  
Dft Method ◽  
Orbital Interaction ◽  
X Ray Diffraction ◽  
Orbital Symmetry ◽  
Orbital Interactions ◽  
Hartree Fock ◽  
Classical Hydrogen Bond

The dual XH (OH and CH) hydrogen-bond-donating property of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) and the strong dual XH–π interaction with arenes were firstly disclosed by theoretical studies. Here, the high accuracy post-Hartree–Fock methods, CCSD(T)/CBS, reveal the interaction energy of HFIP/benzene complex (−7.22 kcal/mol) and the contribution of the electronic correlation energy in the total interaction energy. Strong orbital interaction between HFIP and benzene was found by using the DFT method in this work to disclose the dual XH–π intermolecular orbital interaction of HFIP with benzene-forming bonding and antibonding orbitals resulting from the orbital symmetry of HFIP. The density of states and charge decomposition analyses were used to investigate the orbital interactions. Isopropanol (IP), an analogue of HFIP, and chloroform (CHCl3) were studied to compare them with the classical OH–π, and non-classical CH–π interactions. In addition, the influence of the aggregating effect of HFIP, and the numbers of substituted methyl groups in benzene rings were also studied. The interaction energies of HFIP with the selected 24 common organic compounds were calculated to understand the role of HFIP as solvent or additive in organic transformation in a more detailed manner. A single-crystal X-ray diffraction study of hexafluoroisopropyl benzoate further disclosed and confirmed that the CH of HFIP shows the non-classical hydrogen-bond-donating behavior.

Self-association and stereochemistry study of 2-methylthio-, 2-dimethylaminocyclohexanone oximes and the parent cyclohexanone oxime

2001 ◽  
Vol 57 (5) ◽  
pp. 705-713 ◽  
Author(s):  
Paulo R. Olivato ◽  
Douglas S. Ribeiro ◽  
J. Zukerman-Schpector ◽  
Gabriella Bombieri
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Parent Compound ◽  
Chair Conformation ◽  
Orbital Interaction ◽  
Cyclohexanone Oxime ◽  
X Ray Diffraction ◽  
X Ray ◽  
Shift Analysis ◽  
Self Association

X-ray diffraction analyses of 2-substituted cyclohexanone oximes C5H9(X)C=NOH [X = SMe (1), NMe2 (2)] and of the parent compound [X = H (3)] showed that their cyclohexyl rings are in a slightly distorted chair conformation. These compounds assume in the solid state the (E) configuration bearing the 2-substituents in the axial conformation. Compounds (1) and (2) exist as dimeric and polymeric hydrogen-bond associates, respectively. Low-temperature X-ray analysis of the cyclohexanone oxime (3) showed that the molecules are associated forming two independent trimers. The dimer in (1) and the trimer in (3) are built up via [O—H...N=C] hydrogen bonds, while the polymer of (2) is via the [OH...NMe2] hydrogen bond. The comparative IR νOH and νC=N analysis of the title compounds, in the solid state and in CCl4 solution, fully supports the nature of the associates for (1)–(3) obtained by X-ray diffraction. The IR azomethyne frequency shift analysis (ΔνC=N) also suggests the occurrence of the πC=N/σ*C—X orbital interaction which stabilizes the axial conformations of (1) and (2).

scholarly journals Crystal Structures and Electrical Resistivity of Three Exotic TMTSF Salts with I 3 − : Determination of Valence by DFT and MP2 Calculations

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1119
Author(s):  
Harukazu Yoshino ◽  
Yoshiki Iwasaki ◽  
Rika Tanaka ◽  
Yuka Tsujimoto ◽  
Chiaki Matsuoka
Keyword(s):  
Electrical Resistivity ◽  
Crystal Structures ◽  
Density Functional ◽  
Room Temperature ◽  
Correlation Energy ◽  
X Ray Diffraction ◽  
Hartree Fock ◽  
Salt Structure ◽  
Moller Plesset

Three novel organic conductors (TMTSF)8(I3)5, (TMTSF)5(I3)2, and (TMTSF)4(I3)4·THF (THF = tetrahydrofuran) were synthesized and their crystal structures were characterized by X-ray diffraction analyses, where TMTSF denotes tetramethyltetraselenafulvalene. The crystals of both the (TMTSF)8(I3)5 and (TMTSF)5(I3)2 are composed of one-dimensional stacks of TMTSF trimers separated by TMTSF monomers. The crystal of the (TMTSF)4(I3)4·THF is composed of the TMTSF tetramers and I3− tetramers; and regarded as the elongated rock-salt structure. The electrical conductivity of the (TMTSF)8(I3)5 and (TMTSF)5(I3)2 is about 60 and 50 S·cm−1 at room temperature, respectively. The electrical resistivity of (TMTSF)8(I3)5 is weakly metallic below room temperature and rapidly increases below 88 and 53 K on cooling suggesting two possible phase transitions. The electrical resistivity of (TMTSF)5(I3)2 is semiconducting below room temperature but shows an anomaly around 190 K, below which the activation energy becomes small. The application of hydrostatic pressure up to 1.7 GPa do not change these behaviors of (TMTSF)8(I3)5 and (TMTSF)5(I3)2 very much. A method to evaluate the non-integer valence of crystallographically independent TMTSF molecules is developed by using the DFT (density-functional-theory) and MP2 (Hartree–Fock calculations followed by Møller–Plesset correlation energy calculations truncated at second order) calculations. It is shown that the method gives the valence of the TMTSF molecules of the I3 salts consistent with their electrical properties.

Synthesis and structure of, and bonding in some derivatives of 2,6,9,10-tetraoxatricyclo[3.3.1.13,8]decane

2001 ◽  
Vol 57 (1) ◽  
pp. 63-71 ◽  
Author(s):  
J. Simons ◽  
H. G. Thomas ◽  
S. R. Hall ◽  
G. Raabe
Keyword(s):  
Density Functional ◽  
Correlation Energy ◽  
Single Point ◽  
Molecular Structures ◽  
Electrostatic Model ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
Hartree Fock ◽  
Computational Quantum Chemistry ◽  
Derivatives Of

Five derivatives of 2,6,9,10-tetraoxatricyclo[3.3.1.13,8]decane were synthesized and their molecular structures in the solid state were determined by means of X-ray diffraction analysis. In addition, the structures of all the molecules were optimized at different levels of computational quantum chemistry (HF/6-31G*, B3LYP/6-31G*). Experimentally determined bond lengths were compared with their calculated counterparts, and striking differences between the Hartree–Fock (HF) results and the experimental data could be traced back to the lack of correlation energy in the geometry optimizations. Two of the compounds under consideration are diastereomers and their relative stability was not only calculated with a conventional ab initio method (ZPE+MP2/6-31G*//HF/6-31G*), but also within the framework of density functional theory (B3LYP/6-31G*). In some of the calculations the influence of the solvent was included in single point calculations by means of an electrostatic model. Moreover, combining experimental as well as computational results, the exclusive axial orientation of a Cl atom in one of the compounds could be explained by an interplay of kinetic and energetic effects.

scholarly journals THE METHOD OF INCREMENTS — A WAVEFUNCTION-BASED AB-INITIO CORRELATION METHOD FOR SOLIDS

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2204-2214 ◽  
Author(s):  
BEATE PAULUS
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Ground State ◽  
Infinite System ◽  
Correlation Energy ◽  
Correlation Method ◽  
Many Body ◽  
Hartree Fock ◽  
The Many ◽  
Good Agreement

The method of increments is a wavefunction-based ab initio correlation method for solids, which explicitly calculates the many-body wavefunction of the system. After a Hartree-Fock treatment of the infinite system the correlation energy of the solid is expanded in terms of localised orbitals or of a group of localised orbitals. The method of increments has been applied to a great variety of materials with a band gap, but in this paper the extension to metals is described. The application to solid mercury is presented, where we achieve very good agreement of the calculated ground-state properties with the experimental data.

Relation between Magnetic, Spectroscopic and Structural Properties of Binuclear Copper(II) Complexes of Pentadentate Schiff-base Ligand, Semi-empirical and ab-initio Calculations

2003 ◽  
Vol 58 (5-6) ◽  
pp. 363-372 ◽  
Author(s):  
Y. Elerman ◽  
H. Kara ◽  
A. Elmali
Keyword(s):  
Ab Initio ◽  
Coupling Constants ◽  
Antiferromagnetic Coupling ◽  
X Ray Diffraction ◽  
Hartree Fock ◽  
Ligand Orbital ◽  
Rhf Calculations ◽  
The Difference ◽  
Semi Empirical

The synthesis and characterization of [Cu2(L1)(3,5 prz)] (L1=1,3-Bis(2-hydroxy-3,5-chlorosalicylideneamino) propan-2-ol) 1 and of [Cu2(L2)(3,5 prz)] (L2=1,3-Bis(2-hydroxy-bromosalicylideneamino) propan-2-ol) 2 are reported. The compounds were studied by elemental analysis, infrared and electronic spectra. The structure of the Cu2(L1)(3,5 prz)] complex was determined by x-ray diffraction. The magnetochemical characteristics of these compounds were determined by temperaturedependent magnetic susceptibility measurements, revealing their antiferromagnetic coupling. The superexchange coupling constants are 210 cm−1 for 1 and 440 cm−1 for 2. The difference in the magnitude of the coupling constants was explained by the metal-ligand orbital overlaps and confirmed by ab-initio restricted Hartree-Fock (RHF) calculations. In order to determine the nature of the frontier orbitals, Extended Hückel Molecular Orbital (EHMO) calculations are also reported.

Novel pseudopolymorph of the active metabolite of perindopril

2012 ◽  
Vol 68 (9) ◽  
pp. o341-o343 ◽  
Author(s):  
Joanna Bojarska ◽  
Waldemar Maniukiewicz ◽  
Lesław Sieroń ◽  
Andrzej Fruziński ◽  
Piotr Kopczacki ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Dimethyl Sulfoxide ◽  
Active Metabolite ◽  
Alkyl Chain ◽  
Solvent Molecule ◽  
Carboxylate Group ◽  
X Ray Diffraction ◽  
Structural Units ◽  
X Ray ◽  
Zwitterionic Form

The dimethyl sulfoxide hemisolvate of perindoprilat [systematic name: (1S)-2-((S)-{1-[(2S,3aS,7aS)-2-carboxyoctahydro-1H-indol-1-yl]-1-oxopropan-2-yl}azaniumyl)pentanoate dimethyl sulfoxide hemisolvate], C17H28N2O5·0.5C2H6OS, an active metabolite of perindopril, has been synthesized, structurally characterized by single-crystal X-ray diffraction and compared with its ethanol disolvate analogue [Pascardet al.(1991).J. Med. Chem.34, 663–669]. Both compounds crystallize in the orthorhombicP212121space group in the same zwitterionic form, with a protonated alanine N atom and an anionic carboxylate group at then-alkyl chain. The three structural units present in the unit cell (two zwitterions and the solvent molecule) are held together by a rich system of O—H...O, N—H...O and C—H...O hydrogen-bond contacts.

Molecular tapes in the structure of isoguaninium chloride

2017 ◽  
Vol 74 (1) ◽  
pp. 108-112 ◽  
Author(s):  
Urszula Anna Budniak ◽  
Paulina Maria Dominiak
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Charge Density ◽  
Interaction Energy ◽  
Electrostatic Interaction ◽  
Electrostatic Interactions ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Structure

Isoguanine, an analogue of guanine, is of intrinsic interest as a noncanonical nucleobase. The crystal structure of isoguaninium chloride (systematic name: 6-amino-2-oxo-1H,7H-purin-3-ium chloride), C5H6N5O+·Cl−, has been determined by single-crystal X-ray diffraction. Structure analysis was supported by electrostatic interaction energy (E es) calculations based on charge density reconstructed with the UBDB databank. In the structure, two kinds of molecular tapes are observed, one parallel to (010) and the other parallel to (50\overline{4}). The tapes are formed by dimers of isoguaninium cations interacting with chloride anions. E es analysis indicates that cations in one kind of tape are oriented so as to minimize repulsive electrostatic interactions.

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