Mechanism for di-π-methane rearrangements in nonconjugated systems

The spin-orbit coupling components of the effective one-electron Hamiltonian operator, with the inclusion of symmetry, have been used to formulate mechanisms of spin inversion in triplet photoreactions for the radiationless decay of triplet complexes to singlet ground state products. This has been applied to investigate the photochemical behavior of di-π-methane rearrangement in cyclic and acyclic nonconjugated systems. The results obtained agree with the available experimental results and allow a number of predictions to be made.