scholarly journals III-defined concepts in chemistry: rigid force constants vs. compliance constants as bond strength descriptors for the triple bond in diboryne

2015 ◽  
Vol 6 (7) ◽  
pp. 4086-4088 ◽  
Author(s):  
Jörg Grunenberg
Keyword(s):  
Bond Strength ◽  
Triple Bond ◽  
Force Constants ◽  
Compliance Constants

In a recent publication in this journal, the interpretation of the Braunschweig's diboryne as a true triple bond is questioned.

scholarly journals Molecular recognition of naphthalene diimide ligands by telomeric quadruplex-DNA: the importance of the protonation state and mediated hydrogen bonds

2016 ◽  
Vol 18 (4) ◽  
pp. 2871-2877 ◽  
Author(s):  
A. Spinello ◽  
G. Barone ◽  
J. Grunenberg
Keyword(s):  
Molecular Recognition ◽  
Hydrogen Bonds ◽  
Force Constants ◽  
Protonation State ◽  
Quadruplex Dna ◽  
Naphthalene Diimide ◽  
Compliance Constants

How important are mediated hydrogen bonds in terms of molecular recognition? Compliance Constants (relaxed force constants) give the answer.

scholarly journals Exceptionally Long Covalent CC Bonds—A Local Vibrational Mode Study

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 950
Author(s):  
Alexis Antoinette Ann Delgado ◽  
Alan Humason ◽  
Robert Kalescky ◽  
Marek Freindorf ◽  
Elfi Kraka
Keyword(s):  
Bond Strength ◽  
Radical Cation ◽  
Steric Hindrance ◽  
Force Constants ◽  
Electronic Effects ◽  
Future Design ◽  
Local Vibrational Mode ◽  
Negative Hyperconjugation ◽  
New Guidelines ◽  
First Time

For decades one has strived to synthesize a compound with the longest covalent C−C bond applying predominantly steric hindrance and/or strain to achieve this goal. On the other hand electronic effects have been added to the repertoire, such as realized in the electron deficient ethane radical cation in its D3d form. Recently, negative hyperconjugation effects occurring in diamino-o-carborane analogs such as di-N,N-dimethylamino-o-carborane have been held responsible for their long C−C bonds. In this work we systematically analyzed CC bonding in a diverse set of 53 molecules including clamped bonds, highly sterically strained complexes such as diamondoid dimers, electron deficient species, and di-N,N-dimethylamino-o-carborane to cover the whole spectrum of possibilities for elongating a covalent C−C bond to the limit. As a quantitative intrinsic bond strength measure, we utilized local vibrational CC stretching force constants ka(CC) and related bond strength orders BSO n(CC), computed at the ωB97X-D/aug-cc-pVTZ level of theory. Our systematic study quantifies for the first time that whereas steric hindrance and/or strain definitely elongate a C−C bond, electronic effects can lead to even longer and weaker C−C bonds. Within our set of molecules the electron deficient ethane radical cation, in D3d symmetry, acquires the longest C−C bond with a length of 1.935 Å followed by di-N,N-dimethylamino-o-carborane with a bond length of 1.930 Å. However, the C−C bond in di-N,N-dimethylamino-o-carborane is the weakest with a BSO n value of 0.209 compared to 0.286 for the ethane radical cation; another example that the longer bond is not always the weaker bond. Based on our findings we provide new guidelines for the general characterization of CC bonds based on local vibrational CC stretching force constants and for future design of compounds with long C−C bonds.

The intrinsic strength of the halogen bond: electrostatic and covalent contributions described by coupled cluster theory

2016 ◽  
Vol 18 (48) ◽  
pp. 33031-33046 ◽  
Author(s):  
Vytor Oliveira ◽  
Elfi Kraka ◽  
Dieter Cremer
Keyword(s):  
Bond Strength ◽  
Halogen Bond ◽  
Quantitative Description ◽  
Force Constants ◽  
Coupled Cluster ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Strength Based ◽  
Intrinsic Strength

The first quantitative description of the halogen bond strength based on local vibrational stretching force constants determined with CCSD(T).

Schwingungseigenschaften des PO43-Ions im Monazit-und Zirkon-Gitter

1982 ◽  
Vol 37 (4) ◽  
pp. 380-382 ◽  
Author(s):  
Enrique J. Baran ◽  
Araceli E. Lavat
Keyword(s):  
Rare Earth ◽  
Bond Strength ◽  
Structural Type ◽  
Unit Cell ◽  
Force Constants ◽  
Cell Contraction ◽  
Mean Amplitudes Of Vibration ◽  
The Rare Earth

Abstract The force constants and mean amplitudes of vibration for the PO43- ion present in the lattices of the rare earth orthophosphates of the monazite and zircon types, have been calculated from recently reported Raman data. It is shown that the P-O bond strength depends not only on the overall unit cell contraction but also on the structural type.

Ab-initio-Berechnung kleiner zweiatomiger Moleküle mit minimaler Basis

1972 ◽  
Vol 27 (1) ◽  
pp. 133-137
Author(s):  
W. Ulmer
Keyword(s):  
Bond Strength ◽  
Ab Initio ◽  
Triple Bond ◽  
Gaussian Orbitals

Abstract By means of Frost’s FSGO-method the systems Ne, Ne -Ne, Be -Be, and the molecules B2 as a single and triple bond, CO as a double and triple bond, N2 as a triple bond, and LiH have been calculated. The resulting energies are between 10% and 15% above the HF-limit, but the energy differences of the distinct bond representations are evidently sufficient to give an information about bond relations of a molecule. The type of bond is characterized, defining a “bond-strength”, by the position of the Gaussian orbitals.

From strong to weak NF bonds: on the design of a new class of fluorinating agents

2018 ◽  
Vol 20 (37) ◽  
pp. 23913-23927 ◽  
Author(s):  
Dani Setiawan ◽  
Daniel Sethio ◽  
Dieter Cremer ◽  
Elfi Kraka
Keyword(s):  
Bond Strength ◽  
Quantitative Description ◽  
Force Constants ◽  
New Class ◽  
Strength Based

The first quantitative description of the NF bond strength based on local vibrational stretching NF force constants determined with CCSD(T).

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