THE BEHAVIOR OF THE SINGLET AND TRIPLET SPIN STATES OF METHYLENE-BRIDGED 1,8-NAPHTHOQUINODIMETHANE WITH O2

Article abstract of DOI:10.1016/0040-4020(82)80165-8

It has been shown that thermolysis of naphthocyclopropane 8 yields the singlet 1,8-naphthoquinodimethane 7 by disrotatory ring opening.In fluid solution the singlet biradical prefers to ring close to regenerate the starting material rather than under a 1,2-hydrogen shift to yield phenalene (9).It has been demonstrated that the singlet 7 does not react with O2 or undergo intersystem crossing to ground state triplet 7.It has also been shown by an intricate set of experiments that triplet 7 is produced on photolysis of 8 and that it reacts with O2.Unfortunately, it was not possible to elucidate unequivocally the mechanism by which triplet 7 reacts with O2.