PHOTOCHEMISTRY OF AZOBENZENOPHANES WITH 3-MEMBERED BRIDGES

Azobenzenophanes may be suitable precursor molecules for tetrazetidine s with a four-membered nitrogen ring. The synthesis and photochemistry of azobenzenophanes with at least one three-carbon bridge are reporte d. The photochemistry is dominated by a double left right arrow isomer ization. This class of azobenzenophanes has thermally stable Z,Z isome rs, probably due to the rigidity of the three-carbon bridge. This stif fness, however, hampers tetrazetidine formation. Some clues to tetraze tidine formation are presented and an unusual thermal isomerization E, E --> E,Z is reported.