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 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.

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.

Molecular force field for thionyl fluoride and sulphuryl fluoride

1967 ◽  
Vol 20 (6) ◽  
pp. 1055 ◽  
Author(s):  
R Pichai ◽  
MGK Pillai ◽  
K Ramaswamy
Keyword(s):  
Oxygen Atom ◽  
Potential Energy ◽  
Force Field ◽  
Spectral Data ◽  
Lone Pair ◽  
Molecular Force ◽  
Molecular Force Field ◽  
Energy Constants

The potential energy constants of thionyl fluoride and sulphuryl fluoride were calculated using a modified UBRF. The behaviour of the oxygen atom is found to be similar to that of the lone pair of electrons in thionyl fluoride. The vibrational mean amplitudes of thionyl fluoride and sulphuryl fluoride were also calculated from the vibrational spectral data.

MOLECULAR FORCE FIELD FOR SULFUR TETRAFLUORIDE

1965 ◽  
Vol 43 (2) ◽  
pp. 463-469 ◽  
Author(s):  
M. G. Krishna Pillai ◽  
K. Ramaswamy ◽  
R. Pichai
Keyword(s):  
Force Field ◽  
Bond Length ◽  
Force Constant ◽  
Lone Pair ◽  
Bond Pair ◽  
Molecular Force ◽  
Axial Stretching ◽  
Sulfur Tetrafluoride ◽  
The Relationship ◽  
Lone Pair Interactions

An attempt has been made to modify the UBFF for SF4 by taking into account the presence of the lone pair of electrons. It has been found that the bond pair – lone pair interactions become of importance only when the angle between the bond pair and the lone pair approaches 90°. The equatorial S—F stretching force constant (4.0146 mdyn/Å) is greater than the axial stretching force constant (3.6237 mdyn/Å), which is consistent with the form of the relationship between the force constant and bond length.

Molecular force field evaluation by empirical constraints

1976 ◽  
Vol 73 ◽  
pp. 1051-1057
Author(s):  
Sadao Isotani ◽  
Alain J.-P. Alix
Keyword(s):  
Force Field ◽  
Field Evaluation ◽  
Molecular Force ◽  
Molecular Force Field

Molecular force field and structure of water: Recent microwave results

1974 ◽  
Vol 53 (1) ◽  
pp. 62-76 ◽  
Author(s):  
Robert L. Cook ◽  
Frank C. De Lucia ◽  
Paul Helminger
Keyword(s):  
Force Field ◽  
Structure Of Water ◽  
Molecular Force ◽  
Molecular Force Field

scholarly journals Pengaruh Minimisasi Energi MMFF94 dengan MarvinSketch dan Open Babel PyRx pada Penambatan Molekular Turunan Oksindola Tersubstitusi

ALCHEMY ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 33-40
Author(s):  
Atika Umi Hanif ◽  
Prima Agusti Lukis ◽  
Arif Fadlan
Keyword(s):  
Molecular Docking ◽  
Drug Discovery ◽  
Force Field ◽  
Binding Affinity ◽  
Energy Minimization ◽  
In Silico ◽  
Initial State ◽  
Molecular Force ◽  
Molecular Force Field ◽  
Docking Energy

 In silico technique is widely used for drug discovery because it can predict the conformation of ligands in protein macromolecules and it can calculate the binding affinity. The energy minimization is carried out to make the ligand more stable near the initial state during molecular docking process. The Merck Molecular Force Field (MMFF94) is one type of energy minimization process often used in organic compounds. The molecular docking of substituted oxindole derivatives on indoleamine macromolecules 2,3-dioxygenase (IDO-1, PDB: 2D0T) by MMFF94 minimization operated by MarvinSketch and Open Babel in PyRx showed different results. The binding affinity energy obtained was also quite different, but the ligands have the same conformation and bind the same residue with slightly different bond distances. Keywords: Molecular docking, energy minimization, substituted oxindole, Merck Molecular Force Field 94  Teknik in silico banyak digunakan untuk penemuan senyawa obat karena dapat memprediksi konformasi suatu ligan dalam makromolekul protein dan mampu menghitung nilai afinitas ikatan. Proses minimisasi energi dilakukan untuk menjadikan ligan lebih stabil mendekati keadaan awal selama penambatan molekular berlangsung. Merck Molecular Force Field (MMFF94) adalah salah satu jenis persamaan minimisasi energi yang sering digunakan pada senyawa organik. Hasil pengujian pengaruh minimisasi energi dengan MMFF94 menggunakan program MarvinSketch dan Open Babel dalam PyRx pada turunan oksindola tersubstitusi alkil terhadap makromolekul 2,3-dioxygenase indoleamine (IDO-1, PDB: 2D0T) menunjukkan hasil dengan nilai yang berbeda. Energi afinitas ikatan yang didapatkan juga cukup berbeda, namun ligan memiliki konformasi yang sama dan mengikat residu yang sama dengan jarak ikatan yang sedikit berbeda. Kata kunci: Penambatan molekular, minimisasi energi, oksindola tersubstitusi, Merck Molecular Force Field 94

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