1971-1976 - Profiting from a New Beginning in Geneva.

A few projects of organic photochemistry, which have been investigated in Geneva in 1971-76, are reviewed summarily. They include excited state-selective processes from the n,π* and π,π* triplets and selectively occurring π → π* induced reactions of α,β-unsaturated cyclic ketones, oxadi-π-methane rearrangements and 1,3-acetyl shifts of β,γ-unsaturated methyl ketones, and di-π-methane rearrangements of benzoylnaphthobarrelene compounds. Furthermore, intramolecular triplet energy transfer dependence on rigid donor-acceptor syn-anti topologies between indanone and naphthalene moieties most likely reflects competition between radiationless energy dissipation by through-space aromatic π interaction (amounting to intramolecular exciplex action) and through-σ-bond exchange transfer. Finally, electronically integrating actinometry and time-resolved IR spectroscopy of excited states and reaction intermediates are mentioned.