Synthesis of a highly emissive carboxylated pyrrolidine-fused chlorin for optical sensing of TATP vapours

Abstract

We describe the synthesis and characterization of a new N-methylpyrrolidine-fused meso-tetracarboxyphenylchlorin with highly emissive features. The synthetic approach to obtain the fluorescent chlorin involves the microwave-assisted synthesis of meso-tetrakis (4-methoxycarbonylphenyl)porphyrin, followed by a 1,3-dipolar cycloaddition reaction of this porphyrin with azomethine ylide and, finally, ester hydrolysis under basic conditions. The incorporation and anchoring of the chlorin to a nanostructured porous TiO2 matrix is achieved and optimized for its use as a fluorescent sensor. In particular, we found an efficient detection of the explosive triacetone triperoxide (TATP) in the gas phase. The optical response after analyte exposure is selective and fast, with response time t50 values of less than 10 min under exposure to TATP saturated vapours.