Synthesis, Photophysical, and Computational Studies of Mono‐Azo‐Bridged, Meso‐Tris(2‐Furyl/2‐Thienyl) Substituted Porphyrin‐Arene Hybrids

Abstract

AbstractPorphyrins hybrids have been used as models to study various energy/electron transfer processes. The linkers connecting various subunits in such hybrids are vital in establishing good electronic communication between the subunits and the azo‐bridge can be one of the efficient linkers to do so. Despite of these, the mono azo‐bridged porphyrin‐arene hybrids reported in the literature are only handful and the methods used to create them are not that efficient. In addition, the porphyrins used in this field so far contains only six‐membered meso‐substituents. By keeping these points in mind, we have developed a mild, one‐pot, work‐up‐free, high‐yielding method to synthesize mono‐azo‐bridged, porphyrin‐arene hybrids which also features porphyrins containing three five‐membered substituents like 2‐furyl or 2‐thienyl on their meso‐positions. Along with the NMR and mass characterizations, the photophysical and computational studies of all the reported hybrids are presented. The hybrids containing meso‐tris(2‐furyl/thienyl) substituted porphyrins displayed red‐shifted absorption and emission bands compared to their all‐meso‐aryl‐containing counterparts. In general, all the hybrids displayed enhanced fluorescence quantum yields compared to their precursor porphyrins. Among the series, the meso‐tris(2‐furyl) substituted porphyrin‐arene hybrids exhibited the more significant Stokes shift and small bandgap. The computational studies were in good agreement with the experimental findings.