Premium
Antiaromaticity in relation to 1,3,5,7‐cyclooctatetraene structures
Author(s) -
Politzer Peter,
Murray Jane S.,
Seminario Jorge M.
Publication year - 1994
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560500404
Subject(s) - isodesmic reaction , antiaromaticity , delocalized electron , cyclooctatetraene , polyene , chemistry , ground state , double bond , crystallography , computational chemistry , planar , cyclobutadiene , chemical physics , atomic physics , aromaticity , molecule , density functional theory , physics , organic chemistry , computer science , computer graphics (images)
An isodesmic energy analysis has been carried out at the MP 2/6–31 G *// HF /3–21 G level for the nonplanar ground state ( 1 ) of 1,3,5,7‐cyclooctateraene and for two planar forms, one having complete π delocalization ( 2 ) and the other having alternating single and double bonds ( 3 ). 1 is found to have a considerable degree of stabilization, which is attributed to limited π delocalization. The polyene 3 is the more stable of the two planar forms; it is a transition state in the inversion between two possible nonplanar structures. 2 is found to be a triplet at the Hartree–Fock level and is a critical point on an alternate pathway between the two possible arrangements of alternating single and double bonds in 3 . Both 2 and 3 have negative isodesmic energies, indicating the presence of stabilizing factors. Our results for 3 show that an “antiaromatic” system need not necessarily show a net destabilization. © 1994 John Wiley & Sons, Inc.