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Monoclinic and Triclinic Tetraisopropyl‐ p ‐phenylenediamine: To what Extent do n N /π Interactions Determine Structures?
Author(s) -
Bock Hans,
Göbel Ilka,
Näther Christian,
Havlas Zdenek,
Gavezzotti Angelo,
Filippini Giuseppe
Publication year - 1993
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199317551
Subject(s) - triclinic crystal system , conformational isomerism , monoclinic crystal system , dihedral angle , crystallography , chemistry , lone pair , benzene , crystal (programming language) , crystal structure , molecule , hydrogen bond , organic chemistry , computer science , programming language
Two conformations‐two crystal forms! This is the case for the title compound. The crystal of the conformer with n N /π interactions between the nitrogen lone pairs and the benzene π system (left) is monoclinic, whereas that of the conformer without this interaction (right) is triclinic. The dihedral angles ω (C 2 NC 6 ) are 28 and 74°. According to potential energy surface calculations, the conformers have almost identical enthalpies of formation (Δ H f PM 3= −46 and −47 kJmol −1 ).