Photolysis of r-1, c-2, t-3, t-4-tetraphenylcyclobutane: quantum yield determinations via high performance liquid chromatography

Abstract

r-1, c-2, t-3, t-4-tetraphenylcyclobutane (TPCB) was irradiated in n-butyl chloride solution using 15 ns flashes of 265 nm light. Significant amounts of cis-stilbene were produced during the flash via isomerization of trans-stilbene which is formed with a rate constant k 1 > 5 × 10 8 s −1 according to the reaction TPCB + hv → 2 trans-stilbene. The quantum yield for the cycloreversion of TPCB is φ(−TPCB) ≈ 1.0. The same result was obtained for continuous irradiation using light from a xenon lamp (λ = 240 – 280 nm).