Steric effects on the electronic and molecular structures of nickel(II) and cobalt(II) 2,6-dipyrazol-1-ylpyridine complexes

Polyhedron ◽  
2001 ◽  
Vol 20 (22-23) ◽  
pp. 2829-2840 ◽  
Author(s):  
Joanne M. Holland ◽  
Colin A. Kilner ◽  
Mark Thornton-Pett ◽  
Malcolm A. Halcrow
Keyword(s):  
Molecular Structures ◽  
Steric Effects

Unexpected formation and conversion: role of substituents of 1,3-ynones in the reactivity and product distribution during their reactions with Ru3(CO)12

2019 ◽  
Vol 43 (3) ◽  
pp. 1478-1486
Author(s):  
Lei Xu ◽  
Liping Jiang ◽  
Shasha Li ◽  
Guofang Zhang ◽  
Weiqiang Zhang ◽  
...  
Keyword(s):  
Product Distribution ◽  
Molecular Structures ◽  
Steric Effects ◽  
Unexpected Formation ◽  
Electronic And Steric Effects

Electronic and steric effects of the substituents in 1,3-ynones play key roles in the product distribution and molecular structures.

THE CRYSTAL AND MOLECULAR STRUCTURES OF m-DINITROBENZENE AND p-DINITROBENZENE

1961 ◽  
Vol 39 (8) ◽  
pp. 1638-1644 ◽  
Author(s):  
J. Trotter
Keyword(s):  
Three Dimensional ◽  
Molecular Structures ◽  
Steric Effects ◽  
Crystal And Molecular Structures

The structures of m-dinitrobenzene and p-dinitrobenzene have been refined by three-dimensional (Fo—Fc) syntheses. The results indicate that both nitro groups in each molecule are twisted 11° out of the aromatic plane, about the C—N bonds, in contrast to nitrobenzene, where the whole molecule is completely planar. These molecular configurations are shown to be in accord with those which might be expected from intramolecular steric effects. The dimensions of the three molecules have also been compared.

Regularized regression analysis of digitized molecular structures in organic reactions for quantification of steric effects

2017 ◽  
Vol 38 (21) ◽  
pp. 1825-1833 ◽  
Author(s):  
Shigeru Yamaguchi ◽  
Takahiro Nishimura ◽  
Yuta Hibe ◽  
Masaki Nagai ◽  
Hirofumi Sato ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Molecular Structures ◽  
Organic Reactions ◽  
Steric Effects ◽  
Regularized Regression

scholarly journals Interpretation of Substituent Angular Parameters of Monosubstituted Benzenes by Means of ab initio STO-3G Fully Optimized Molecular Structures and Charges Densities. Part VI of the Series: “Crystallographic Studies and Physicochemical Properties of π-Electron Systems”

1986 ◽  
Vol 41 (7) ◽  
pp. 895-903 ◽  
Author(s):  
Tadeusz Marek Krygowski ◽  
Günter Häfelinger ◽  
Josef Schüle
Keyword(s):  
Ab Initio ◽  
Linear Regression Analysis ◽  
Multiple Linear Regression Analysis ◽  
Molecular Structures ◽  
Steric Effects ◽  
Electron Charge ◽  
Charge Densities ◽  
Dual Regression ◽  
Monosubstituted Benzenes ◽  
Electron Effects

AbstractThe angular variations of molecular structures calculated for 17 monosubstituted derivatives of benzene by use of ab initio analytical gradient optimization at the STO -3G level have been correlated by multiple linear regression analysis with Mulliken σ- and π-electron charge densities at corresponding ring carbon atoms. Variations of angles γ at meta positions are solely due to π-electron effects (R = 0.961). Changes in angles β at ortho positions are independent of σ- or π-electron effects but may be related to steric effects (R = 0.719) alone or additionally to charge densities on ortho protons (for dual regression R = 0.846). Angles a at ipso atom s depend significantly on both, σ- and π-electron charge densities in the ratio of 70% to 21% with R = 0.974 for dual regression. Variations of angles δ para-positions depend on all three effects considered (with correlation coefficient for a triple regression R = 0.951) in the ratio 37.6% :2 8 .3% : 34.1% for steric effects, σ- and π-electron charge densities, respectively.

The Structure of Two 1-(Nitrophenyl)-Δ2-pyrazolines: a Crystallographic and Theoretical Study

2004 ◽  
Vol 57 (11) ◽  
pp. 1103 ◽  
Author(s):  
Glenn P. A. Yap ◽  
Ibon Alkorta ◽  
Nadine Jagerovic ◽  
José Elguero
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Gas Phase ◽  
Density Functional ◽  
Theoretical Study ◽  
Chemical Shifts ◽  
Molecular Structures ◽  
Steric Effects ◽  
Functional Theory ◽  
Crystal And Molecular Structures

The crystal and molecular structures of two nitrophenylpyrazolines have been determined. The geometries have been used as starting geometries for density functional theory (DFT) calculations. The differences in conformation between both molecules and between the solid state and gas phase are explained in terms of steric effects. An attractive intramolecular N···N interaction between the nitro group and the pyrazoline N2 nitrogens has been found. Absolute shieldings have been calculated (GIAO) and compared with experimental 1H and 13C chemical shifts.

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