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.

Crystal and electronic structure of the new ternary phosphide Ho5Pd19P12

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Olha Zhak ◽  
Oksana Karychort ◽  
Volodymyr Babizhetskyy ◽  
Chong Zheng
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Structure Property Relationships ◽  
Metallic Bonding ◽  
Crystal And Electronic Structure ◽  
Insight Into

Abstract The title compound was prepared from the pure elements by sintering. The crystal structure was investigated by means of powder X-ray diffraction data. Ho5Pd19P12 exhibits the hexagonal Ho5Ni19P12-type structure with space group P 6 ‾ 2 m $P‾{6}2m$ , a = 13.1342(2), c = 3.9839(1) Å, R I = 0.060, R p = 0.080. The crystal structure can be described as a combination of two types of the structural units, [HoPd6P3] and [Ho3Pd10P6], respectively, mutually displaced by 1/2 along the crystallographic c axis. Quantum chemical calculations have been performed to analyze the electronic structure and provide deeper insight into the structure-property relationships. The results of the quantum chemical calculations indicate that the material features metallic bonding between Ho and Pd and covalent bonding between Pd and P.

Matrix Isolation and Electronic Structure of Di- and Tridehydrobenzenes

2010 ◽  
Vol 63 (7) ◽  
pp. 1013 ◽  
Author(s):  
Michael Winkler ◽  
Wolfram Sander
Keyword(s):  
Electronic Structure ◽  
Quantum Chemical ◽  
Structural Information ◽  
Matrix Isolation ◽  
The Past ◽  
Matrix Isolation Spectroscopy ◽  
The Matrix ◽  
Recent Developments ◽  
Quantum Chemical Computations ◽  
Insight Into

Within the past four decades, matrix isolation spectroscopy has emerged as the method of choice for obtaining direct structural information on benzynes and related dehydroaromatics. In combination with quantum chemical computations, detailed insight into the structure and reactivity of di-, tri-, and tetradehydrobenzenes has been obtained. This Review focuses on rather recent developments in aryne chemistry with a special emphasis on the matrix isolation of tridehydrobenzenes and related systems.

scholarly journals Tert-butyl esters of 2,3-diaryl-3-arylaminopropanoic acids - stereoselective synthesis, isolation, spectroscopic and structural elucidation

2011 ◽  
Vol 13 (3) ◽  
pp. 12-17 ◽  
Author(s):  
Donka Tasheva ◽  
Sonya Zareva
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Stereoselective Synthesis ◽  
Uv Spectroscopy ◽  
Structural Elucidation ◽  
Butyl Esters ◽  
H Nmr ◽  
Spectroscopic Characteristics

Tert-butyl esters of 2,3-diaryl-3-arylaminopropanoic acids - stereoselective synthesis, isolation, spectroscopic and structural elucidation A series of seven substituted tert-butyl esters of 2,3-diaryl-3-arylaminopropanoic acids has been synthesized, isolated, spectroscopically and structurally elucidated. An influence of the substituents on the spectroscopic characteristics and conformations is discussed using the data of the linear-polarized IR- (IR-LD), UV-spectroscopy and 1H-NMR. Theoretical quantum chemical calculations are carried out, with a view to explaining and supporting the experimental optical properties and the electronic structure. The stereoselective synthesis of the corresponding diastereoisomers is optimized, thus giving good yields (62-72%) and purity of the compounds

scholarly journals Mono BN-substituted analogues of naphthalene: a theoretical analysis of the effect of BN position on stability, aromaticity and frontier orbital energies

2018 ◽  
Vol 42 (15) ◽  
pp. 12968-12976 ◽  
Author(s):  
Milovan Stojanović ◽  
Marija Baranac-Stojanović
Keyword(s):  
Electronic Structure ◽  
Theoretical Analysis ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Frontier Orbital ◽  
Orbital Energies ◽  
Structure Changes ◽  
Insight Into

An insight into the electronic structure changes driven by CC → BN substitution in a naphthalene system has been given by quantum chemical calculations.

Conformation and electronic structure of aromatic chloroformates

1987 ◽  
Vol 52 (4) ◽  
pp. 970-979 ◽  
Author(s):  
Otto Exner ◽  
Pavel Fiedler
Keyword(s):  
Electronic Structure ◽  
Oxygen Atom ◽  
Strong Interaction ◽  
Electron Distribution ◽  
Room Temperature ◽  
Functional Group ◽  
Dipole Moments ◽  
Carbonyl Oxygen ◽  
Nonpolar Solvents ◽  
Single Method

Aromatic chloroformates Ib-Ie were shown to exist in the ap conformation, in agreement with aliphatic chloroformates, i.e. the alkyl group is situated cis to the carbonyl oxygen atom as it is the case in all esters. While 4-nitrophenyl chloroformate (Ie) is in this conformation in crystal, in solution at most several tenths of percent of the sp conformation may be populated at room temperature and in nonpolar solvents only. A new analysis of dipole moments explained the previous puzzling results and demonstrated the impossibility to determine the conformation by this single method, in consequence of the strong interaction of adjoining bonds. If, however, the ap conformation is once proven, the dipole moments reveal some features of the electron distribution on the functional group, characterized by the enhanced polarity of the C-Cl bond and reduced polarity of the C=O bond. This is in agreement with the observed bond lengths and angles.

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