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Nature of the highest occupied molecular orbitals of trans ‐ and cis ‐bicyclo[4.1.0]hept‐3‐enes
Author(s) -
Gassman Paul G.,
MlinarićMajerski Kata,
Kovač Branka,
Chen Han,
Dixon David A.
Publication year - 1995
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.610080305
Subject(s) - chemistry , molecular orbital , bicyclic molecule , bent molecular geometry , computational chemistry , atomic orbital , ab initio , spectral line , density functional theory , ring (chemistry) , crystallography , molecule , stereochemistry , physics , organic chemistry , quantum mechanics , electron , astronomy
Photoelectron spectra of trans ‐bicyclo[4.1.0]hept‐3‐ene and two methyl derivatives, 1–3, and cis ‐bicyclo[4.1.0]hept‐3‐ene and three of its derivatives, 4–7, were measured. Ab initio molecular orbital (MO) and density functional theory (DFT) calculations were performed on these compounds. By combining the results of the experimental and computational trends, it was established that the highest occupied molecular orbitals (HOMOs) of 1–3 are the ‘twist’ bent σ bond at the fusion between the two rings whereas for 4–7 the HOMOs are the π orbital in the six‐membered ring. The DFT ordering is the same as that suggested by the photoelectron spectra whereas at the MO level the HOMO always corresponds to the π orbital. The intensities of the photoelectron spectra were calculated at the DFT level and good qualitative agreement with experiment was found.