Dendronized Porphyrins: Molecular Design and Synthesis

In this review, we report different methods and strategies to synthesize flexible and rigid dendronized porphyrins. We will focus on porphyrin dendrimers that have been reported in the last 10 years. Particularly, in our research group, we have designed and synthesized different series of dendronized porphyrins (free base and metallated) with pyrene units at the periphery and Frechet-type dendritic arms. The Lindsey methodology has allowed the synthesis of meso-substituted porphyrins with various substitution patterns, such as symmetric, dissymmetric, or unsymmetric. Porphyrin dendrimers have been prepared by different synthetic methodologies; one of the most reported being the convergent method, where the dendrons are first prepared and further linked to a meso-substituted functionalized porphyrin unit, which will constitute the core of the dendrimer. Another interesting synthetic approach is the use of a reactive dendron bearing a terminal aldehyde functional group to form the final porphyrin core. In this way, a two-armed dendronized dissymmetric porphyrin core can be prepared from a dendritic precursor and a dipyrromethene derivative. This strategy is very convenient to prepare low-generation dendritic porphyrins. The divergent approach is another well-known methodology for porphyrin dendrimer synthesis, mostly used for achieving high-generation dendrimers. Click chemistry reaction has been advantageous for the development of more complex porphyrin dendritic structures. This reaction presents important advantages, such as high yields and mild reaction conditions, which permit the assembly of different multiporphyrin dendritic structures. In the constructs presented in this review, the emission of the porphyrin moiety has been observed, leading to potential applications in artificial photosynthesis, sensing, nanomedicine, and biological sciences.

Automated summary

This review discusses different methods and strategies for synthesizing flexible and rigid dendronized porphyrins, with a particular focus on those reported in the last 10 years. The Lindsey methodology allows for the synthesis of porphyrins with various substitution patterns, and different synthetic methodologies have been used to prepare porphyrin dendrimers. Click chemistry reaction has been advantageous for the development of more complex porphyrin dendritic structures. The constructs presented in this review have potential applications in artificial photosynthesis, sensing, nanomedicine, and biological sciences.