Photochemical E(trans)–Z(cis) Isomerization in 9-Anthraceneacrylic Esters

Abstract Several (1–6) 9-anthraceneacrylic esters were synthesized in order to study photochemical E(trans)–Z(cis) isomerization. All of the compounds 1–6 underwent selective E-to-Z isomerization upon direct excitation (> 400 nm) in organic solvents, leading to the formation of a thermodynamically less stable Z isomer over 96%. Triplet sensitized isomerization selectively produces the Z-to-E isomer in over 98%. The higher quantum yield of isomerization observed in the triplet-sensitized Z-to-E isomerization process informs us that a “quantum chain” process is in operation. Fluorescence data generated on all compounds indicate that the E-to-Z isomerization process involves a charge-transfer or polar singlet excited state.