Electronic effect of and mutual polarizability in groups attached to oxygen via their C, Si, Ge, and B atoms

1982 ◽  
Vol 47 (2) ◽  
pp. 613-616 ◽  
Author(s):  
Josef Pola ◽  
Václav Chvalovský
Keyword(s):  
Electronic Effect ◽  
Relative Basicity ◽  
Polarizability Effect ◽  
Effect Parameter ◽  
Relative Acidity

Relative acidity of triphenylhydroxy substituted germane and stannane is consistent with superior electrondonating effect of (C6H5)3Ge and (C6H5)3Sn groups in these compounds. Relative basicity data of alkyl(alkoxy) boranes, methanes, silanes, and germanes (RO)nZRm (Z = B, C, Si, and Ge) are compiled. The variation of the electronic effect parameter σ of fully alkylated RmZ-groups upon substitution of their alkyl with ethoxy substituent appears for Z=B and Si to be influenced by mutual polarizability effect of ethoxy substituents. Mutual polarizability of ethoxy substituents attached to carbon and germanium is negligible.

The effects controlling the oxygen basicity in alkoxysilanes (RO)nSi(CH3)4-n. The mutual polarizability effect of alkoxy groups attached to silicon

1979 ◽  
Vol 44 (3) ◽  
pp. 750-755 ◽  
Author(s):  
Josef Pola ◽  
Marie Jakoubková ◽  
Václav Chvalovský
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Electronic Effect ◽  
Linear Regression Analysis ◽  
Effect Of Substituents ◽  
Relative Basicity ◽  
Polarizability Effect ◽  
Alkoxy Groups ◽  
Individual Series

Relative basicity of the oxygen in alkoxysilanes (RO)nSi(CH3)3-n having n = 1-4 and various electrondonating and electronwithdrawing groups R measured as Δν(OH) of phenol due to its interaction with these compounds in CCl4 is shown to be chiefly controlled by the electronic effect of substituents R. Linear regression analysis of the Δν(OH) vs n relatioship for individual series (RO)nSi(CH3)4-n suggests the operation of the polarizability effect of RO groups becoming more important with increasing electronwithdrawing nature of R.

The electronic effects in and the oxygen basicity of some oxygen-containing boranes

1979 ◽  
Vol 44 (12) ◽  
pp. 3688-3694 ◽  
Author(s):  
Josef Pola ◽  
Marie Jakoubková ◽  
Václav Chvalovský
Keyword(s):  
Hydrogen Bonds ◽  
Ir Spectra ◽  
Electronic Effect ◽  
Electronic Effects ◽  
Relative Basicity ◽  
Polarizability Effect ◽  
Alkoxy Groups

The oxygen relative basicity of di-n-butylboronous anhydride ((n-C4H9)2B)2O, ethyl di-n-butylboronite (n-C4H9)2BOC2H5 and some orthoborates (RO)3B having electrondonating and electronwithdrawing groups R was measured from the IR spectra of hydrogen bonds of phenol interacting with these compounds in CCl4 and analysed by means of the Taft equation. The substituent electronic effect of (n-C4H9)2B- and (RO)2B-groups attached to the oxygen of the-OR and -OB= moieties has been estimated asa more electronwithdrawing than that of structurally alike R2Z- and (RO)2Z-groups having Z = CH and SiCH3 and is discussed in terms of the vacant 2p orbital of the boron and a weak, if any, mutual polarizability effect of the alkoxy groups in orthoborates. The trimethylsiloxy group in trimethylsilyl borate possesses reduced electronwithdrawing ability compared to that in ((CH3)3SiO)3SiCH3 as a consequence of its great polarizability.

The electronic effect of silyl groups in different XYZSi-R systems

1980 ◽  
Vol 45 (3) ◽  
pp. 861-875 ◽  
Author(s):  
Josef Pola ◽  
Václav Chvalovský
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Electronic Effect ◽  
Intramolecular Interaction ◽  
Linear Regression Analysis ◽  
Silyl Groups ◽  
Effect Parameter ◽  
Universal Scale

The electronic effect parameter σ for XYZSi-R compounds as silyl hydrides XYZSiH, alkoxysilanes XYZSiOL (L = alkyl or substituted alkyl) and α-carbofunctional silanes XYZSiCH2Y (Y = Cl and OL) having X, Y and Z substituents of various electron-donating and electronaccepting ability has been established by a linear regression analysis of the IR and NQR data on these compounds. It is shown that no universal scale of the σ constant for silyl XYZSi-groups can be established. The electronic effect transmission of the X, Y and Z substituents through the silicon depends on the type of the intramolecular interaction between the silicon and the R group and the electronic effect parameter of silyl groups should be treated as a variable whose exact value depends on the nature of the particular molecule.

The Model for Calculation the Hall Effect Parameter

2004 ◽  
Vol 9 (2) ◽  
pp. 129-138
Author(s):  
J. Kleiza ◽  
V. Kleiza
Keyword(s):  
Magnetic Field ◽  
Field Effect ◽  
Magnetic Field Effect ◽  
Mapping Method ◽  
Sample Thickness ◽  
System Of Nonlinear Equations ◽  
Specific Resistivity ◽  
Conformal Mapping Method ◽  
Effect Parameter ◽  
The Magnetic Field

A method for calculating the values of specific resistivity ρ as well as the product µHB of the Hall mobility and magnetic induction on a conductive sample of an arbitrary geometric configuration with two arbitrary fitted current electrodes of nonzero length and has been proposed an grounded. During the experiment, under the constant value U of voltage and in the absence of the magnetic field effect (B = 0) on the sample, the current intensities I(0), IE(0) are measured as well as the mentioned parameters under the effect of magnetic fields B1, B2 (B1 ≠ B2), i.e.: IE(β(i)), I(β(i)), i = 1, 2. It has been proved that under the constant difference of potentials U and sample thickness d, the parameters I(0), IE(0) and IE(β(i)), I(β(i)), i = 1, 2 uniquely determines the values of the product µHB and specific resistivity ρ of the sample. Basing on the conformal mapping method and Hall’s tensor properties, a relation (a system of nonlinear equations) between the above mentioned quantities has been found.

Variable electronic effect of silyl groups attached to oxygen

1978 ◽  
Vol 43 (3) ◽  
pp. 746-752 ◽  
Author(s):  
Josef Pola ◽  
Václav Chvalovský
Keyword(s):  
Electronic Effect ◽  
Silyl Groups

The effect of solvation by acetone on the basicity of silylalkylamines

1979 ◽  
Vol 44 (9) ◽  
pp. 2828-2831 ◽  
Author(s):  
Zlata Papoušková ◽  
Vlasta Fialová ◽  
Václav Chvalovský
Keyword(s):  
Potentiometric Titration ◽  
Electronic Interaction ◽  
Relative Basicity

The relative basicity of fifteen methylethoxysilylalkylamines of the type (CH3)3-m(C2H5O)m.Si(CH2)nNH2 in acetone has been studied by potentiometric titration. For n 1 the basicity increases with increasing m, which is likely due to increasing electronic interaction of the oxygen of acetone with the silicon of silylalkylamines. The basicity of silylmethylamines (n = 1) changes nonsystematically, probably as a consequence of the competing action of opposite effects.

Acid-base properties of metals and glasses of Na2O.P2O5-xB2O3 system

1984 ◽  
Vol 49 (10) ◽  
pp. 2355-2362 ◽  
Author(s):  
Juraj Leško ◽  
Marie Dorušková ◽  
Jan Tržil
Keyword(s):  
Boron Oxide ◽  
A Priori ◽  
Optical Basicity ◽  
Galvanic Cell ◽  
Acid Base ◽  
Tetrahedral Configuration ◽  
Relative Basicity ◽  
Base Theory ◽  
Base Properties

Boron oxide in the Na2O.P2O5-x B2O3 system behaves as a Lux base. Its addition to Na2O.P2O5 brings about transformation of a Co(II) indicator from octahedral to tetrahedral configuration, increase in the optical basicity ΛPb(II), increase in the relative basicity of the melt as determined by means of a galvanic cell, and depolymerization reactions releasing PO43- ions. In the Na2O-B2O3 system free of P2O5, boron oxide behaves as a Lux acid. The amphoretic nature of B2O3 is explained in terms of Lux's acid-base theory extended in analogy with the protolysis theory. The theoretical optical basicity values do not indicate the amphoretic behaviour of B2O3 because in this approach boron oxide is a priori regarded as more acidic than Na2O.P2O5.

Tuning and understanding the electronic effect of Co-Mo-O sties in bifunctional electrocatalysts for ultralong-lasting rechargable zinc-air battery

2021 ◽  
Author(s):  
Yi Guan ◽  
Nan Li ◽  
Jiao He ◽  
Yongliang Li ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Electronic Effect ◽  
Metal Organic Frameworks ◽  
Core Shell ◽  
Zeolitic Imidazolate Frameworks ◽  
Assembly Strategy ◽  
The Core ◽  
Bifunctional Electrocatalysts ◽  
Metal Organic ◽  
Air Battery

Herein, we report a post-assembly strategy by growing the bimetallic Co/Zn zeolitic imidazolate frameworks (BIMZIF) on the surface of the customized Mo metal-organic frameworks (MOFs) (Mo-MOF) to prepare the core-shell...

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