Effect of intermolecular hydrogen bonding on the molecular structures of imidazole and 1,2,4-triazole: A study by ab initio molecular orbital calculations

1994 ◽  
Vol 5 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Fabio Ramondo ◽  
Luigi Bencivenni ◽  
Gustavo Portalone ◽  
Aldo Domenicano
Keyword(s):  
Hydrogen Bonding ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Molecular Structures ◽  
Molecular Orbital Calculations ◽  
Intermolecular Hydrogen Bonding

Molecular structures and ab initio molecular orbital calculations of the optically active derivatives of 1-aminocyclopropane-1-carboxylic acid

2003 ◽  
Vol 655 (2) ◽  
pp. 229-241 ◽  
Author(s):  
Zoran Džolić ◽  
Mario Cetina ◽  
Damir Kovaček ◽  
Antonija Hergold-Brundić ◽  
Draginja Mrvoš-Sermek ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Optically Active ◽  
Molecular Structures ◽  
Molecular Orbital Calculations ◽  
Derivatives Of

Ion-specificity for hydrogen-bonding hydration of polymer: an approach by ab initio molecular orbital calculations II

2001 ◽  
Vol 574 (1-3) ◽  
pp. 195-211 ◽  
Author(s):  
Hajime Muta ◽  
Tesong Sin ◽  
Akira Yamanaka ◽  
Susumu Kawauchi ◽  
Mitsuru Satoh
Keyword(s):  
Hydrogen Bonding ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Ion Specificity

Amino and cyano N atoms in competitive situations: which is the best hydrogen-bond acceptor? A crystallographic database investigation

2001 ◽  
Vol 57 (6) ◽  
pp. 850-858 ◽  
Author(s):  
Nahossé Ziao ◽  
Jérôme Graton ◽  
Christian Laurence ◽  
Jean-Yves Le Questel
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Amino Nitrogen ◽  
Lone Pair ◽  
Molecular Surface ◽  
Molecular Orbital Calculations ◽  
Hydrogen Bond Acceptor

The relative hydrogen-bond acceptor abilities of amino and cyano N atoms have been investigated using data retrieved from the Cambridge Structural Database and via ab initio molecular orbital calculations. Surveys of the CSD for hydrogen bonds between HX (X = N, O) donors, N—T—C≡N (push–pull nitriles) and N—(Csp 3) n —C≡N molecular fragments  show that the hydrogen bonds are more abundant on the nitrile than on the amino nitrogen. In the push–pull family, in which T is a transmitter of resonance effects, the hydrogen-bonding ability of the cyano nitrogen is increased by conjugative interactions between the lone pair of the amino substituent and the C≡N group: a clear example of resonance-assisted hydrogen bonding. The strength of the hydrogen-bonds on the cyano nitrogen in this family follows the experimental order of hydrogen-bond basicity, as observed in solution through the pK HB scale. The number of hydrogen bonds established on the amino nitrogen is greater for aliphatic aminonitriles N—(Csp 3) n —C≡N, but remains low. This behaviour reflects the greater sensitivity of the amino nitrogen to steric hindrance and the electron-withdrawing inductive effect compared with the cyano nitrogen. Ab initio molecular orbital calculations (B3LYP/6-31+G** level) of electrostatic potentials on the molecular surface around each nitrogen confirm the experimental observations.

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