Optimization of orthogonal reactions on bodipy dyes for one-pot synthesis of light harvesting dendrimers

Abstract

For more than a decade, synthetic organic chemistry has dealt with focusing on highly selective and efficient reactions that can proceed under mild conditions which would then be categorized under the term “orthogonal click chemistry”. These types of reaction have served number of applications for years as in peptide synthesis, homogeneous catalysis and development of supramolecular systems. On the other side, after a partial understanding of how photosynthetic bacteria and plants harvest solar radiation in order to carry their necessary carbon dioxide reduction reaction by converting light to chemical energy, artificial light harvesting systems have captivated a lot attention of scientists. Because today’s one of the biggest and inevitable problems is to discover/invent alternative energy sources/devices for future demands, these artificial light harvesting and solar concentrator systems are highly open for further development and optimization. However, like most other macromolecular systems, synthesis of these kind of devices should be straightforward so as to decrease the cost and to increase the efficiency. At this point, orthogonal click reactions, being mild and efficient synthetic models, can undoubtedly be worthwhile to consider as proper tools for easy preparation of light harvesting molecules. Here we propose a synthesis of thiol, Michael accepting groups, amine and isothiocyanate modified BODIPY dyes for light harvesting cascade preparation. Moreover, the optimization of Michael addition type thiol – ene reaction of these functionalized dyes has been discussed. Among methyl methacrylate, cyanoacetic acid and nitroolefin functionalizations, it was found that nitroolefin attached BODIPY dyes are the most reactive one. The achieved product has been investigated in terms of fluorescence and energy transfer.