STRAINING THE DOUBLE-BOND IN 1,2-DIHYDROXYETHYLENE - A SIMPLE THEORETICAL-MODEL FOR THE ENEDIOL MOIETY IN RUBISCO SUBSTRATE AND ANALOGS

The potential energy surfaces for rotation and pyramidalization on the double bond for the singlet ground state and the first triplet state in 1,2-dihydroxyethylene are calculated with the ab initio molecular orbital method. Full geometry optimizations are carried out at the HF-SCF including MP2 level of theory with 6-31G* basis sets. The premises of a relatively simple electronic mechanism for the (O-3(2)) oxygenation reaction on a strained enediol are obtained. The idea is based on the fact that the energy gap between the singlet and first triplet state of a dienol moiety decreases to a small value where excitation to the triplet state may be induced by oxygen.