The Substituent Dependence of the Direct trans->cis Photoisomerization of Donor Substituted 4'-Diphenylphosphinyl trans-Stilbenes

Article abstract of DOI:10.1007/BF00798370

From the fluorescence quantum yield φ_f the fluorescence decay time τ^w_f and the quantum yield φ_tc of the trans->cis photoisomerization results the fraction α of perpendicular singlet (perp-S₁) decaying to ground state trans-stilbenes 1.The α values of the donor substituted 4'-diphenylphosphinyl-trans-stilbenes 1 in the solvents toluene and n-propanol are dependent on the donor substituent in 1 and the solvent.It is concluded for 1 that increasing polarity of the first excited singlet state (tr-S₁) promotes the trans->cis photoisomerization. - Keywors: Stilbenes; trans-cis Photoisomerization; Influence of Substituents