Electronic aspects of the chlorination of 2,4-dichloropentane as a model for the study of the chlorination of poly(vinyl chloride)

1980 ◽  
Vol 45 (2) ◽  
pp. 376-385
Author(s):  
Miroslav Bárta ◽  
Rudolf Lukáš ◽  
Miloslav Kolínský
Keyword(s):  
Quantum Chemical ◽  
Interatomic Bond ◽  
Frontier Orbital ◽  
Indo Method ◽  
Electron Densities ◽  
Total Electron ◽  
H Nmr ◽  
Poly Vinyl Chloride ◽  
Orbital Electron ◽  
Spin Densities

The semiempirical quantum chemical method CNDO/2 was used in the calculation of the electronic structure of TT and GG conformers of d,1-2,4-dichloropentane and TG' conformer of meso-2,4-dichloropentane. Relative stability of their model conformations was determined and compared with data of 1H-NMR spectroscopy. The TT conformer of d,l-2,4-dichloropentane was found to possess the highest stability. The chlorination mechanism of 2,4-dichloropentane was discussed using the knowledge of the total electron densities on atoms, frontier orbital electron densities and interatomic bond indices. The INDO method was employed to calculate the spin densities of stereoisomers of 2,4-dichloropentane. Results thus obtained led to a conclusion that the reactivity of monocarbon groups in the chlorination of 2,4-dichloropentane decreased in the order CH3-> -CH2-> -CHCl-.

The Calculation of Some CH Wag Group Frequencies in Substituted Benzenes, Naphthalenes, and Acetylenes

1976 ◽  
Vol 30 (6) ◽  
pp. 589-593 ◽  
Author(s):  
Norman B. Colthup
Keyword(s):  
Electron Density ◽  
Molecular Orbital ◽  
Computer Calculation ◽  
Force Constants ◽  
General Tendency ◽  
Electron Densities ◽  
Total Electron Density ◽  
Substituted Benzenes ◽  
Total Electron ◽  
Orbital Electron

Nineteen quantitative relationships are presented which enable the calculation of certain CH wag group frequencies in some substituted benzenes, naphthalenes, and acetylenes. Four involve computer calculation of molecular orbital electron densities and one involves Hammett values. The remaining 14 relationships involve simple functions between different CH wag group frequencies based on electron density relationships. This verifies a general tendency for unsaturated CH wag force constants to be weakened when the total electron density on the carbon of the CH is increased.

scholarly journals Three New Biflavonoids from Chinese Dragon's Blood, Dracaena cochinchinensis

2012 ◽  
Vol 7 (5) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Jing Guan ◽  
Shun-Xing Guo
Keyword(s):  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Chemical Calculation ◽  
Dragon’S Blood ◽  
Esi Ms ◽  
H Nmr ◽  
Cd Spectrum ◽  
The Absolute ◽  
Circular Dichroïsm ◽  
C Nmr

Three new biflavonoids, named (2 Rγ S)-3′-methoxy-8-methylsocotrin-4′-ol (1), (2 Sγ R)-3′-methoxy-8-methylsocotrin-4′-ol (2), and (2 Rγ R)-8-methylsocotrin-4′-ol (3), were isolated from Chinese Dragon's blood [Dracaena cochinchinensis (Lour.) S. C. Chen], together with two known ones. The structures of these new biflavonoids were elucidated by a combination of HR-ESI-MS, 1H NMR, 13C NMR, HMQC, and HMBC spectra. The absolute configurations of compounds 1-4 were determined by quantum chemical calculation of the circular dichroism spectrum and comparison with the experimental CD spectrum.

Synthesis of metal-free tetraazaisobacteriochlorin and via template condensation of phthalogenes

2020 ◽  
Vol 24 (05n07) ◽  
pp. 878-886
Author(s):  
Semyon V. Dudkin ◽  
Takahiro Kawata ◽  
Svetlana A. Belova ◽  
Yusuke Okada ◽  
Nagao Kobayashi
Keyword(s):  
Mass Spectrometry ◽  
Quantum Chemical ◽  
2D Nmr ◽  
Metal Free ◽  
Tert Butyl ◽  
H Nmr ◽  
Nmr Data ◽  
Template Condensation ◽  
Td Dft ◽  
Low Symmetry

The indium(III) complexes of (4-(tert-butyl)phenyl)-substituted tetraazaisobacteriochlorin (TAiBC) and tetraazachlorin (TAC) were synthesized by direct template condensation of bis(4-(tert-butyl)phenyl)fumaronitrile and tetramethylsuccinonitrile using indium(III) ion as a matrix. The corresponding metal-free tetraazaisobacteriochlorin and tetraazachlorin were obtained by demetallation of their indium(III) complexes. These metal-free complexes were characterized using elemental analysis, mass-spectrometry, 1H and [Formula: see text]C{1H}NMR spectroscopy, UV-vis and MCD spectroscopy as well as DFT and TD-DFT calculations. Due to the low symmetry of the molecules, the NMR data were complex, but could be assigned by collecting 1D- and 2D NMR data and comparing with the results of quantum chemical calculations. From the position of the pyrrole proton signal (6.78 ppm), it was found that the diatropic current of TAiBC is much weaker than that of TAC, and plausibly the weakest among porphyrinoids so far reported. Absorption and MCD spectra were reasonably interpreted using the calculated absorption spectra.

Electron densities and the VSEPR model of molecular geometry

1992 ◽  
Vol 70 (3) ◽  
pp. 742-750 ◽  
Author(s):  
R. J. Gillespie
Keyword(s):  
Electron Density ◽  
Present Status ◽  
Electron Pair ◽  
Molecular Geometry ◽  
Physical Basis ◽  
Valence Shell ◽  
Electron Densities ◽  
Total Electron Density ◽  
Total Electron

This paper reviews the present status of the VSEPR model of molecular geometry in relation to electron densities. The discussion is based on the electron pair domain version of this model. The fundamental postulates of the model are summarized and illustrated by a discussion of the structures of some molecules with five and seven electron pair domains in the valence shell, including the recently discovered ions XeF5− and XeOF6−. The total electron density does not provide any obvious support for the model and although electron density deformation maps do provide some support they are not always reliable. The Laplacian of the electron density, however, shows the presence of valence shell charge concentrations that correspond closely in number and properties to the electron pair domains of the VSEPR model. This correspondence between electron pair domains and valence shell charge concentrations provides a physical basis for a better understanding of the VSEPR model. Keywords: VSEPR model, electron densities, molecular geometry, Laplacian of the electron density, electron pair domain.

scholarly journals The Effects of Epoxidized Acrylated Castor Oil (EACO) on Soft Poly (vinyl chloride) Films as a Main Plasticizer

2018 ◽  
Vol 20 (4) ◽  
pp. 13-19 ◽  
Author(s):  
Fei Song ◽  
Haoyu Xia ◽  
Puyou Jia ◽  
Meng Zhang ◽  
Lihong Hu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Hydrogen Peroxide ◽  
Solvent Extraction ◽  
Castor Oil ◽  
Second Step ◽  
H Nmr ◽  
Plasticized Pvc ◽  
Poly Vinyl Chloride ◽  
Nmr Techniques

Abstract In this work, an environmentally friendly type plasticizer was introduced. The synthesis consisted of two steps. In the first step, castor oil (CO) was acrylated and then the acrylated castor oil (ACO) was epoxidized with the presence of formic acid and hydrogen peroxide in the second step. The epoxidized acrylated castor oil (EACO) was characterized by FTIR and 1H-NMR techniques. The EACO was used as a main plasticizer to obtain plasticized PVC materials and compared with DOP. The results showed that EACO improved polyvinyl-chloride (PVC) plasticization performance and reduced Tg from 81.06°C to 1.40°C. Plasticized PVC materials with EACO showed similar mechanical properties and better thermal stability than DOP. EACO had better volatility stabilities, migration and solvent extraction in PVC than DOP. EACO can be used to replace DOP to prepare soft films.

Electronic structure and properties of alkoxymethylenemalonic acid derivatives

1979 ◽  
Vol 44 (5) ◽  
pp. 1423-1433 ◽  
Author(s):  
Dušan Ilavský ◽  
Jiří Krechl ◽  
Petr Trška ◽  
Josef Kuthan
Keyword(s):  
Electronic Structure ◽  
Quantum Chemical ◽  
Chemical Reactivity ◽  
Dipole Moments ◽  
Structure And Properties ◽  
Geometrical Isomers ◽  
H Nmr ◽  
Geometrical Isomerism ◽  
Pmr Spectra ◽  
Insight Into

Six compounds RO(H)C=C(X)CN with R = CH3 or C2H5 and X = CO2CH3, CO2C2H5 or CN are characterized by some spectral data (IR, UV, 1H NMR - solvent effect). The PMR spectra did not confirm the presence of two geometrical isomers. Employing the quantum chemical calculations of the substance with R = CH3 and X = CO2CH3 based on EHT, PPP, HMO and CNDO/2, the geometrical isomerism is discussed in relation to the experimental dipole moments. The HMO indices of chemical reactivity agree with our present synthetic insight into nucleophilic substitution of the derivatives under study.

Gilded Chalices: Tetra-aurated Calix[4]arenes

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1061-1072 ◽  
Author(s):  
Ulf H. Strasser ◽  
Beate Neumann ◽  
Hans-Georg Stammler ◽  
Raphael J. F. Berger ◽  
Norbert W. Mitzela
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Quantum Chemical ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Elemental Analyses ◽  
One Step ◽  
Energy Of Formation

Abstract 5,11,17,23-Tetrakis(trimethylsilylethynyl)-25,26,27,28-tetra-n-propoxycalix[4]arene (1) was synthesised in two steps starting from 25,26,27,28-tetra-n-propoxycalix[4]arene, and the structure of 1 was determined by X-ray diffraction. Compound 1 was desilylated (K2CO3) to give 5,11,17,23- tetrakis(ethynyl)-25,26,27,28-tetra-n-propoxycalix[4]arene (2), which was tetra-aurated under basic conditions (NaOEt, THF) with a series of phosphane-gold chlorides (o-Tol3PAuCl, Ph3PAuCl, Ph2MePAuCl, PhMe2PAuCl, Me3PAuCl, Cy3PAuCl, t-Bu3PAuCl) to afford in good to excellent yields the tetra-aurated tetraethynylcalix[4]arene species 3-9 in one step [with phosphane ligands o-Tol3P (3), Ph3P (4), Ph2MeP (5), PhMe2P (6), Me3P (7), Cy3P (8), t-Bu3P (9)]. All compounds were characterised by 1H NMR and infrared spectroscopy, mass spectrometry and by elemental analyses, additionally 3, 4, 5, 8 and 9 by 13C{1H}, and 3-6, 8 and 9 by 31P{1H} NMR spectroscopy. The molecular structures of complexes 3 and 9 were determined by X-ray diffraction and show pinched-cone conformations, but neither intra- nor intermolecular attractive aurophilic Au···Au contacts. The acceptor ability of complexes 3 and 9 was investigated by complexation attempts with various phosphane-gold chlorides and xenon gas under pressure, but interactions could not be determined experimentally. The formation of a complex between xenon and gilded calix[4]arene could, however, be predicted for fluorine-substituted species and with very small phosphane ligands (PH3) on the basis of quantum-chemical calculations; the energy of formation is 9:6 kJ mol-1. The crystal structure of Ph2MePAuCl was also determined and shows Au···Au-bonded dimers.

A novel biobased plasticizer of epoxidized cardanol glycidyl ether: synthesis and application in soft poly(vinyl chloride) films

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 56171-56180 ◽  
Author(s):  
Jie Chen ◽  
Zengshe Liu ◽  
Jianchun Jiang ◽  
Xiaoan Nie ◽  
Yonghong Zhou ◽  
...  
Keyword(s):  
Vinyl Chloride ◽  
Glycidyl Ether ◽  
H Nmr ◽  
Poly Vinyl Chloride ◽  
Ether Synthesis ◽  
C Nmr

A novel plasticizer derived from cardanol, and epoxied cardanol glycidyl ether (ECGE), was synthesized and characterized by 1H-NMR and 13C-NMR.

scholarly journals Error analysis of Abel retrieved electron density profiles from radio occultation measurements

2010 ◽  
Vol 28 (1) ◽  
pp. 217-222 ◽  
Author(s):  
X. Yue ◽  
W. S. Schreiner ◽  
J. Lei ◽  
S. V. Sokolovskiy ◽  
C. Rocken ◽  
...  
Keyword(s):  
Electron Density ◽  
Radio Occultation ◽  
Electron Content ◽  
Electron Densities ◽  
Density Profiles ◽  
Total Electron ◽  
The North ◽  
Spring Equinox ◽  
Electron Density Profiles ◽  
Artificial Plasma

Abstract. This letter reports for the first time the simulated error distribution of radio occultation (RO) electron density profiles (EDPs) from the Abel inversion in a systematic way. Occultation events observed by the COSMIC satellites are simulated during the spring equinox of 2008 by calculating the integrated total electron content (TEC) along the COSMIC occultation paths with the "true" electron density from an empirical model. The retrieval errors are computed by comparing the retrieved EDPs with the "true" EDPs. The results show that the retrieved NmF2 and hmF2 are generally in good agreement with the true values, but the reliability of the retrieved electron density degrades in low latitude regions and at low altitudes. Specifically, the Abel retrieval method overestimates electron density to the north and south of the crests of the equatorial ionization anomaly (EIA), and introduces artificial plasma caves underneath the EIA crests. At lower altitudes (E- and F1-regions), it results in three pseudo peaks in daytime electron densities along the magnetic latitude and a pseudo trough in nighttime equatorial electron densities.

RuII–hydride–tropcomplexes: X-ray single-crystal determination and quantum-chemical calculations

2013 ◽  
Vol 69 (12) ◽  
pp. 1421-1426 ◽  
Author(s):  
Gustavo Santiso-Quinones ◽  
Rafael Rodriguez-Lugo ◽  
Vittorio Sacchetti ◽  
Hansjörg Grützmacher
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Theoretical Calculations ◽  
Data Sets ◽  
Space Group ◽  
X Ray ◽  
H Nmr ◽  
Axial Ligands ◽  
Catalytically Active ◽  
Difference Fourier

As part of our search for catalytically active RuII–hydride complexes, we have synthesized and crystallographically characterized three different ruthenium species, namely dihydrido[(SR)-(10,11-η)-N-(pyridin-2-ylmethyl-κN)-5H-dibenzo[a,d]cyclohepten-5-amine](triphenylphosphane-κP)ruthenium(II) tetrahydrofuran monosolvate, [RuH2(C21H18N2)(C18H15P)]·C4H8O or (SR)-[RuII(H)2{N-(pyridin-2-ylmethyl)tropNH}(PPh3)]·THF, (1), chlorido{(1SR,2RS)-N,N′-bis[(10,11-η)-5H-dibenzo[a,d]cyclohepten-5-amine]ethane-1,2-diamine-κ2N,N′}hydridoruthenium(II) dimethoxyethane hemisolvate, [RuClH(C32H28N2)]·0.5C4H10O2or (1SR,2RS)-[RuII(H)(Cl){tropNH(CH2)2HNtrop}]·DME, (2), and chlorido{(1SR,2RS)-N,N′-bis[(10,11-η)-5H-dibenzo[a,d]cyclohepten-5-amine]propane-1,3-diamine-κ2N,N′}hydridoruthenium(II), [RuClH(C33H30N2)] or (1SR,2RS)-[RuII(H)(Cl){tropNH(CH2)3HNtrop}], (3), wheretropis 5H-dibenzo[a,d]cycloheptene. In all three complexes, the RuIIcenter resides in an octahedral coordination environment. For (1)–(3), the hydride atoms were located in a difference Fourier map and were refined freely. In solution, the1H NMR spectra of all species show the presence of the hydride resonance. Comparison with quantum-chemical calculations reveals that the crystallographic data sets are plausible. In every case, the prediction is in very good agreement with the observed X-ray data. Not only the observed geometry is predicted well but also the Ru—H(hydride) bond lengths are reproduced remarkably well. Complexes (1) and (2) crystallized in the triclinicP\overline{1} space group, while (3) crystallized in the tetragonal space groupI41/a. For (3), there is disorder of the axial ligands producing two isomers (in a 98.7:1.3 ratio). Details of the synthesis, characterization, X-ray analysis, and theoretical calculations for complexes (1)–(3) are presented.

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