MOLECULAR AND ELECTRONIC-STRUCTURE AND GAS-PHASE PYROLYTIC GENERATIONOF 7,7'-DIOXASESQUINORBORNENES

Structural and photoelectron spectroscopic (PES) features of 7.7'-diox a analogs of syn (syn-2) and anti-sesquinorbornenes (anti-2) are inves tigated. It is shown that the B3LYP/6-31G and B3PW91/6-31G* DFT metho ds are well-suited for studying the geometrical properties of large or ganic molecules containing nonplanar double bonds, as is evident from comparisons with MP2/6-31G results and the available neutron diffract ion and X-ray data. It is also shown that the anti isomer is less stab le than the syn isomer of 2, in accordance with the stability ordering of syn-1 and anti-1. Finally, PES evidence for the formation of anti- 2 upon pyrolytic decomposition of the corresponding p-lactone is given and discussed.