Photochemistry of naphthalimide photoacid generators.
The photophysical properties of a series of 1,8-naphthalimide photoacid generators were studied by steady state fluorescence and phosphorescence spectroscopy. Emission and excitation anisotropies, triplet quantum yields in polar and nonpolar solvent and photoacid generation were evaluated. The singlet excited state exhibits a low polarity and is strongly deactivated by an efficient intersystem crossing process. In protic solvent, a homolytic singlet cleavage of the N-O bond occurs and leads to the acid production. The existence of a triplet state close to the singlet state was clearly evidenced. The presence of close singlet excited states is supported by fluorescence anisotropy and picosecond laser spectroscopy experiments. Results of DFT calculations well confirm the experimental contentions and yield important information about the cleavage process involved in such compounds.
Malval
Jean-Pierre
JP
Department of Photochemistry, UMR CNRS 7525, Université de Haute Alsace, ENSCMu 3 rue Alfred Werner, 68093 Mulhouse, France.
Suzuki
Shota
S
Morlet-Savary
Fabrice
F
Allonas
Xavier
X
Fouassier
Jean-Pierre
JP
Takahara
Shigeru
S
Yamaoka
Tsuguo
T