scholarly journals Chemical Bonding by the Chemical Orthogonal Space of Reactivity

2020 ◽  
Vol 22 (1) ◽  
pp. 223
Author(s):  
Mihai V. Putz
Keyword(s):  
Chemical Bond ◽  
Chemical Bonding ◽  
Important Case ◽  
Chemical Hardness ◽  
Numerical Illustration ◽  
Analytical Expression ◽  
Orthogonal Space ◽  
Open Questions ◽  
Present Formalism ◽  
Homo Lumo

The fashionable Parr–Pearson (PP) atoms-in-molecule/bonding (AIM/AIB) approach for determining the exchanged charge necessary for acquiring an equalized electronegativity within a chemical bond is refined and generalized here by introducing the concepts of chemical power within the chemical orthogonal space (COS) in terms of electronegativity and chemical hardness. Electronegativity and chemical hardness are conceptually orthogonal, since there are opposite tendencies in bonding, i.e., reactivity vs. stability or the HOMO-LUMO middy level vs. the HOMO-LUMO interval (gap). Thus, atoms-in-molecule/bond electronegativity and chemical hardness are provided for in orthogonal space (COS), along with a generalized analytical expression of the exchanged electrons in bonding. Moreover, the present formalism surpasses the earlier Parr–Pearson limitation to the context of hetero-bonding molecules so as to also include the important case of covalent homo-bonding. The connections of the present COS analysis with PP formalism is analytically revealed, while a numerical illustration regarding the patterning and fragmentation of chemical benchmarking bondings is also presented and fundamental open questions are critically discussed.

Chemical bonding analysis of excited states using the adaptive natural density partitioning method

2019 ◽  
Vol 21 (18) ◽  
pp. 9590-9596 ◽  
Author(s):  
Nikolay V. Tkachenko ◽  
Alexander I. Boldyrev
Keyword(s):  
Chemical Bond ◽  
Excited States ◽  
Chemical Bonding ◽  
Bonding Analysis ◽  
Novel Approach ◽  
Natural Density ◽  
Adaptive Natural Density Partitioning

A novel approach to chemical bond analysis for excited states has been developed.

High Pressure and Chemical Bonding in Materials Chemistry

2006 ◽  
Vol 61 (7) ◽  
pp. 799-807 ◽  
Author(s):  
Gérard Demazeau
Keyword(s):  
High Pressure ◽  
Chemical Bond ◽  
Chemical Bonding ◽  
High Pressures ◽  
Chemical Properties ◽  
General Rule ◽  
Research Area ◽  
Chemical Compositions ◽  
Materials Chemistry ◽  
Novel Materials

Materials chemistry under high pressures is an important research area opening new routes for stabilizing novel materials or original structures with different compositions (oxides, oxoborates, nitrides, nitridophosphates, sulfides,. . .).Due to the varieties of chemical compositions and structures involved, high pressure technology is also an important tool for improving the investigations on chemical bonding and consequently the induced physico-chemical properties.Two different approaches can be described: (i) the chemical bond is pre-existing and in such a case, high pressures lead to structural transformations, (ii) the chemical bond does not exist and high pressures are able to help the synthesis of novel materials. In both cases the condensation effect (ΔV < 0 between precursors and the final product) is the general rule. In addition, through the improvement of the reactivity, high pressures can lead to materials that are not reachable through other chemical routes.

THE CHEMICAL BOND IN SEMICONDUCTORS: THE GROUP V B TO VII B ELEMENTS AND COMPOUNDS FORMED BETWEEN THEM

1956 ◽  
Vol 34 (12A) ◽  
pp. 1369-1376 ◽  
Author(s):  
E. Mooser ◽  
W. B. Pearson
Keyword(s):  
Optical Properties ◽  
Chemical Bond ◽  
Chemical Bonding ◽  
Valence Bond ◽  
Electrical And Optical Properties ◽  
Group V ◽  
New Model ◽  
Bond Model

A brief review is first given of the developments which led to an understanding of the important role played by chemical bonding in semiconductors. The properties of the Group V B to VII B elements and of some compounds formed between these elements are then considered according to the valence bond model of Pauling. This leads to the conclusion that the band scheme in these substances is somewhat different to that which has been generally accepted, and we discuss the new model in relation to their electrical and optical properties.

scholarly journals Quantum Chemical Examination on Structural, Spectroscopic, Population and Molecular Orbitals Analysis of NLO Active 4-Methoxyaniline Hydroquinone for Optoelectronics Applications

2019 ◽  
Vol 8 (4S2) ◽  
pp. 891-902
Keyword(s):  
Quantum Chemical ◽  
Chemical Potential ◽  
Population Analysis ◽  
Molecular Geometry ◽  
Mulliken Charge ◽  
Chemical Hardness ◽  
Optical Efficiency ◽  
Chemical Examination ◽  
Vibrational Assignments ◽  
Homo Lumo

Quantum chemical calculations of molecular geometry, HOMO-LUMO, Mulliken charge distributions and vibrational assignments of 4-methoxyaniline hydroquinone (4MAHQ) were carried out by DFT (B3LYP) and HF methods. Spectral analysis on 4MAHQ has been studied both by the computational and experimental methods to assign vibrational modes of all the functional groups. The investigation is extensive to calculate the FMOs, population analysis, Molecular Electrostatic Potential and Non Linear Optical efficiency of 4MAHQ. The electron affinity, ionization and chemical potential, electrophilicity index, chemical hardness, electro negativity and global softness of 4-methoxyaniline hydroquinone were calculated by FMO analysis

Synthesis and DFT Quantum Chemical Calculations of 2-Oxopyrimidin-1(2H)-yl-Urea and Thiorea Derivatives

2019 ◽  
Vol 41 (5) ◽  
pp. 841-841
Author(s):  
Murat Saracoglu Murat Saracoglu ◽  
Zulbiye Kokbudak Zulbiye Kokbudak ◽  
Esra Yalcin and Fatma Kandemirli Esra Yalcin and Fatma Kandemirli
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Chemical Potential ◽  
Energy Gap ◽  
Basis Set ◽  
Chemical Hardness ◽  
Spectroscopic Techniques ◽  
Solvent Phase ◽  
B3lyp Method ◽  
Homo Lumo

A series of the new 2-oxopyrimidin-1(2H)-yl-urea (3a-c) and thiourea (4a-d) derivatives were synthesized by the reaction of arylisocyanates (2a-c) or arylisothiocyanates (2d-g) and the 1-amino-5-(4-methoxybenzoyl)-4-(4-methoxyphenyl)pyrimidin-2(1H)-one (1). The structures of the compounds 3a-c and 4a-d were characterized by elemental analysis, FT-IR, 1H and 13C-NMR spectroscopic techniques. In addition to experimental study in order to find molecular properties, quantum-chemical calculations of the synthesized compounds were carried out by using DFT/B3LYP method with basis set of the 6-311G(d,p). Quantum chemical features such as HOMO, LUMO, HOMO-LUMO energy gap, Ionization potential, chemical hardness, chemical softness, electronegativity, chemical potential, dipole moment etc. values for gas and solvent phase of neutral molecules were calculated and discussed.

Synthesis and DFT Quantum Chemical Calculations of Novel Pyrazolo[1,5-c]pyrimidin-7(1H)-one Derivatives

2019 ◽  
Vol 41 (3) ◽  
pp. 479-479
Author(s):  
Murat Saracoglu Murat Saracoglu ◽  
Zulbiye Kokbudak Zulbiye Kokbudak ◽  
Zeynep imen and Fatma Kandemirli Zeynep imen and Fatma Kandemirli
Keyword(s):  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Chemical Potential ◽  
Energy Gap ◽  
Chemical Hardness ◽  
Spectroscopic Techniques ◽  
Solvent Phase ◽  
B3lyp Method ◽  
Ft Ir ◽  
Homo Lumo

In this study, a convenient procedure for the preparation of pyrazolo[1,5-c]pyrimidin-7(1H)-one derivatives is described. The new pyrazolo[1,5-c]pyrimidin-7(1H)-one derivatives (2a, b) were synthesized from the cyclocondensation reaction of the compounds 1-amino-5-(4-methoxybenzoyl)-4-(4-methoxyphenyl)pyrimidin-2(1H)-one (1a) and 1-amino-5-(4-methylbenzoyl)-4-(4-methylphenyl)pyrimidin-2(1H)-one (1b) with α-chloroacetone. The structures of the compounds (2a, b) were characterized by elemental analysis, FT-IR, 1H-NMR and 13C-NMR spectroscopic techniques. In addition to experimental study in order to find molecular properties, quantum-chemical calculations of the new pyrazolo[1,5-c]pyrimidin-7(1H)-one derivatives (2a, b) were carried out by using DFT/B3LYP method with the 6-311G(d,p) and 6-311++G(2d,2p) basic sets. Quantum chemical features such as HOMO, LUMO, HOMO-LUMO energy gap, chemical hardness, chemical softness, electronegativity, chemical potential, dipole moment etc. values for gas and solvent phase of neutral molecules were calculated and discussed.

Coumarin-based random copolymer

2017 ◽  
Vol 31 (6) ◽  
pp. 729-744 ◽  
Author(s):  
Feride Akman
Keyword(s):  
Thermal Degradation ◽  
Molecular Electrostatic Potential ◽  
Chemical Potential ◽  
Energy Gap ◽  
Degradation Mechanism ◽  
Random Copolymer ◽  
Chemical Hardness ◽  
Degradation Reaction ◽  
Boundary Model ◽  
Homo Lumo

In this article, coumarin-based random copolymer which can be utilized for atom transfer radical polymerization was investigated both theoretically and experimentally. The thermal degradation mechanism and the activation energies ( Ea) were obtained by means of the Coats–Redfern (CR), Tang, and Flynn–Wall–Ozawa (FWO) methods. The thermal degradation reaction mechanism for random copolymer obeyed the phase boundary model (contracting volume, R3) of solid-state mechanism. The thermodynamic properties in the range from 100 K to 500 K have been obtained. The calculated HOMO–LUMO energy gap and electronic properties, such as chemical hardness ( η), electron affinity ( A), chemical potential ( μ0), global softness ( ζ), electronegativity ( χ), global electrophilicity ( ω), and dipole moment ( μ), were investigated and discussed. The molecular electrostatic potential analysis of the random copolymer was also computed.

Early work on chemical bonding in relation to solid state physics

1981 ◽  
Vol 378 (1773) ◽  
pp. 207-218 ◽  
Keyword(s):  
State Physics ◽  
Solid State ◽  
Chemical Bond ◽  
Chemical Bonding ◽  
Royal Society ◽  
Limited Extent ◽  
Solid State Physics

A symposium on the beginnings of solid state physics, organized by Sir Nevill Mott, F. R. S., was held by the Royal Society from 30 April to 2 May 1979, and 26 papers contributed to this symposium were published in Proc. R. Soc. Lond . A 371, 1-177 (1980). One aspect of solid state physics, that dealing with the nature of the chemical bond in solids, was presented to only a quite limited extent. The present paper, which emphasizes my own early work in this field, has been written to supplement the symposium papers.

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