scholarly journals On the Significance of Lone Pair/Lone Pair and Lone Pair/Bond Pair Repulsions in the Cation Affinity and Lewis Acid/Lewis Base Interactions

ACS Omega ◽  
2018 ◽  
Vol 3 (9) ◽  
pp. 11331-11339 ◽  
Author(s):  
Younes Valadbeigi ◽  
Jean-François Gal
Keyword(s):  
Lewis Acid ◽  
Lone Pair ◽  
Pair Bond ◽  
Lewis Base ◽  
Bond Pair ◽  
Cation Affinity

Molecular force field for chlorine trifluoride

1965 ◽  
Vol 18 (3) ◽  
pp. 261 ◽  
Author(s):  
MG Krishna ◽  
K Ramaswamy ◽  
R Pichai
Keyword(s):  
Force Field ◽  
Force Constant ◽  
Lone Pair ◽  
Pair Interaction ◽  
Pair Bond ◽  
Approximate Relation ◽  
Lone Pairs ◽  
Bond Pair ◽  
Molecular Force ◽  
Molecular Force Field

An attempt has been made to modify the UBFF for chlorine trifluoride by taking into account the presence of lone pairs of electrons, on the lines suggested by Pariseau, Wu, and Overend. It was found that the lone-pair-bond-pair interaction is less than the lone-pair-lone-pair interaction which is considerably lower than the stretching force constant for the lone pair of electrons. An approximate relation between the above interactions was obtained.

Changing Partners: Complex Substitution

Reactions ◽  
2011 ◽  
Author(s):  
Peter Atkins
Keyword(s):  
Metal Atom ◽  
Lewis Acid ◽  
Periodic Table ◽  
Noble Metals ◽  
Lone Pair ◽  
Lewis Base ◽  
Central Metal Atom ◽  
Important Special Case ◽  
Lewis Bases ◽  
Special Case

I shall now describe a special case of the Lewis acid–base reactions I introduced in Reaction 9. I showed there that a Lewis acid is a species that can accept a lone pair from another incoming species and form a bond to it, that a Lewis base is a species that provides that lone pair, and that the result of this sharing is a complex of the two species joined together by a chemical bond. The important special case I would like to share with you here is when the Lewis acid is a metal atom or ion, especially but not necessarily one drawn from the d-block of the periodic table (a ‘transition metal’). The d-block consists of the elements that make up the skinny central rectangle of the periodic table. They include important constructional metals, such as iron, nickel, and copper, and also the chemically aloof ‘noble’ metals gold, platinum, and silver. The Lewis base that I focus on will be a molecule or ion that also has an independent existence in the wild, such as water, H2O, or ammonia, NH3. In most cases the complex consists of the central metal atom or ion with up to six Lewis bases clustering around it. In this context, the Lewis bases are known as ‘ligands’ (from the Latin for ‘bound’) and I shall use that term here. I don’t want you to think that I am embarking on stratospherically esoteric material again. These metal complexes are hugely important in many aspects of the everyday world. For instance, chlorophyll is a complex of magnesium and is responsible for capturing the energy of the Sun for photosynthesis (Reaction 26). There is hardly a more important molecule. One that comes close in importance is haemoglobin, an elaborate complex of iron, which ensures that oxygen reaches all your cells and keeps you alive. Many pigments are complexes, so your life is decorated and made more colourful by them. Some pharmaceuticals are complexes based on platinum, so one day, perhaps even now, you might be kept alive by one of these artificial complexes.

scholarly journals Lead(ii): Lewis acid and occasional base, as illustrated by its complex with 1,5-naphthalenedisulfonate and 5-methyl-1,10-phenanthroline

2017 ◽  
Vol 46 (35) ◽  
pp. 11533-11536 ◽  
Author(s):  
Jack Harrowfield ◽  
Pierre Thuéry
Keyword(s):  
Hydrogen Bonding ◽  
Lewis Acid ◽  
Lone Pair ◽  
Lewis Base ◽  
Valence Shell

Hydrogen bonding to lead(ii) evidences the Lewis base character of this cation due to its valence shell lone pair.

Molecular force field for bromine pentafluoride

1968 ◽  
Vol 46 (14) ◽  
pp. 2393-2397 ◽  
Author(s):  
M. G. Krishna Pillai ◽  
P. Parameswaran Pillai
Keyword(s):  
Force Field ◽  
Lone Pair ◽  
Pair Interaction ◽  
Pair Bond ◽  
Halogen Atoms ◽  
Bond Pair ◽  
Molecular Force ◽  
Molecular Force Field ◽  
Lone Pair Electrons

An attempt has been made to study the influence of lone pair electrons on the potential constants of BrF5 with a modified Urey–Bradley force field. It is found that the lone pair – bond pair repulsion is greater than the bond pair – bond pair repulsion. It is also concluded from a study of other molecules containing halogen atoms that the ratio of lone pair – bond pair interaction to bond pair – bond pair interaction is very nearly 1.23.

Molecular Force Field for Seleninyl Fluoride

1970 ◽  
Vol 25 (3) ◽  
pp. 246-249
Author(s):  
M. G. Krishna Pillai ◽  
P. Parameswaran Pillai
Keyword(s):  
Double Bond ◽  
Force Field ◽  
Fixed Ratio ◽  
Lone Pair ◽  
Pair Bond ◽  
Double Bond Character ◽  
Bond Pair ◽  
Molecular Force ◽  
Lone Pair Electrons ◽  
Bond Character

A modified U.B.F.F. containing terms directly related to lone pair electrons, has been used to evaluate the potential constants of SeOF2. The value obtained for the Se-O stretching constant supports the double bond character of the bond. The lone pair-bond pair repulsion bears a fixed ratio to the non-bonded repulsion (FeF/FFF=1.24 and Feo/FoF=1.23) and this result is in agreement with earlier conclusions.

The structure and activity of potassium supported on SBA-15 molecular sieve: Density functional theory study

2014 ◽  
Vol 13 (01) ◽  
pp. 1350076 ◽  
Author(s):  
Bing Liu ◽  
Daxi Wang ◽  
Zhongxue Wang ◽  
Zhen Zhao ◽  
Yu Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Lewis Acid ◽  
Molecular Sieve ◽  
Active Sites ◽  
Density Functional ◽  
Structural Model ◽  
Vibrational Frequencies ◽  
Oxygen Molecule ◽  
Lewis Base ◽  
Functional Theory

The geometries, vibrational frequencies, electronic properties and reactivity of potassium supported on SBA-15 have been theoretically investigated by the density functional theory (DFT) method. The structural model of the potassium supported on SBA-15 was constructed based on our previous work [Wang ZX, Wang DX, Zhao Z, Chen Y, Lan J, A DFT study of the structural units in SBA-15 mesoporous molecular sieve, Comput. Theor. Chem.963, 403, 2011]. This paper is the extension of our previous work. The most favored location of potassium atom was obtained by the calculation of substitution energy. The calculated vibrational frequencies of K /SBA-15 are in good agreement with the experimental results. By analyzing the properties of electronic structure, we found that the O atom of Si - O (2)- K group acts as the Lewis base center and the K atom acts as the Lewis acid center. The reactivity of K /SBA-15 was investigated by calculating the activation of oxygen molecule. The oxygen molecule can be activated by K /SBA-15 with an energy barrier of 103.2 kJ/mol. In the final state, the activated oxygen atoms become new Lewis acid centers, which are predicted to act as the active sites in the catalytic reactions. This study provides a deep insight into the properties of supported potassium catalysts and offers fundamental information for further research.

Erratum to “Synthesis and structure of potential Lewis acid–Lewis base bifunctional catalysts: 2-N,N-diisopropylaminobenzylboronate derivatives” [J. Organomet. Chem. 690 (2005) 4784–4793]

2006 ◽  
Vol 691 (3) ◽  
pp. 538
Author(s):  
Samuel W. Coghlan ◽  
Richard L. Giles ◽  
Judith A.K. Howard ◽  
Leonard G.F. Patrick ◽  
Michael R. Probert ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Lewis Base ◽  
Bifunctional Catalysts

Lewis Base Mediated β-Elimination and Lewis Acid Mediated Insertion Reactions of Disilazido Zirconium Compounds

2013 ◽  
Vol 135 (40) ◽  
pp. 15225-15237 ◽  
Author(s):  
KaKing Yan ◽  
Juan J. Duchimaza Heredia ◽  
Arkady Ellern ◽  
Mark S. Gordon ◽  
Aaron D. Sadow
Keyword(s):  
Lewis Acid ◽  
Lewis Base ◽  
Insertion Reactions ◽  
Zirconium Compounds

scholarly journals Lewis acid- and/or Lewis base-catalyzed [3+2] cycloaddition reaction: synthesis of pyrazoles and pyrazolines

2008 ◽  
Vol 49 (48) ◽  
pp. 6768-6772 ◽  
Author(s):  
Palakodety Radha Krishna ◽  
Empati Raja Sekhar ◽  
Florence Mongin
Keyword(s):  
Lewis Acid ◽  
Cycloaddition Reaction ◽  
Lewis Base ◽  
Reaction Synthesis
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