Investigations of Low-Symmetrical Tetraaryltetrabenzoporphyrins Produced by Mixed Condensation Reactions

Abstract

Within the past decade, tetraaryltetrabenzoporphyrins (TATBPs) have gained rising attention due to their potential in various fields of materials science and medicinal chemistry. However, this class of compounds still lacks in structural diversity, especially in the case of low-symmetrical compounds. Herein, mixed condensations were utilized to generate TATBPs with different substituents either in the meso-positions or the periphery of the macrocycle with total yields of 55–58%. The separation of crude mixtures was achieved by feasible chromatographic purification. The influence of symmetry on the electronic properties of TATBPs was studied by optical spectroscopy, electrochemistry, and X-ray diffraction.

Single crystal field-effect transistor of tetrabenzoporphyrin with a one-dimensionally extended columnar packing motif exhibiting efficient charge transport properties

“…More importantly, recent synthetic efforts are providing a variety of BP derivatives. 6,35–37 Considering that TIPS-H 2 BP shows excellent stability, elaborately-designed BP derivatives have great potential to be promising semiconducting materials. We believe that fine-tuning of the BP structure enables a significant improvement in the charge transport property.…”

Main Strategies for the Synthesis of meso-Arylporphyrins

“…The structural diversity of tetraaryltetrabenzopor­phyrins was expanded by applying the proposed methodology in combination with mixed condensation [ 163 ]. The condensation of 4,7-dihydro-2 Н -4,7-ethano­isoindole with a mixture of two aromatic aldehydes or of two different isoindole derivatives with benzalde­hyde was used to obtain low-symmetry TATBPs with various substituents either in the meso -aryl fragments or on the periphery of the macroheterocycle with an overall yield of 55–58%.…”

Addressing Environmental Challenges of Porphyrin Mixtures Obtained from Statistical Syntheses

“…On the other hand, statistical approaches give rapid access to a large library of potentially interesting molecules, or to unsymmetrical products that are otherwise more difficult to synthesize selectively. [1][2][3] In that regard, macrocyclic tetrapyrroles such as porphyrins, and particularly their low-symmetrical substitution isomers, are often difficult to obtain in good yields, and purification by selective crystallization is usually not possible. [4] Thus, sophisticated selective synthetic procedures are required, to overcome exhaustive chromatographic purification steps.…”

“…[23,24] To give an example, the E-factor in pharmaceutical industry is around 25-100, [23] whereas a typical Lindsey-type A 4 porphyrin synthesis reaches values > 2000. [25,26] E ¼ m waste m product (1) Nowadays, a powerful tool to overcome the aforementioned problems can be the development of automated systems. Hereby, not only the interactions between the operator and the systems are reduced, but also the reproducibility and reliability of processes are increased, while simultaneously decreasing the required time and costs for chemical and human resources.…”

“…Especially in the case of small differences among the products, separation and isolation can become very demanding. On the other hand, statistical approaches give rapid access to a large library of potentially interesting molecules, or to unsymmetrical products that are otherwise more difficult to synthesize selectively [1–3] . In that regard, macrocyclic tetrapyrroles such as porphyrins, and particularly their low‐symmetrical substitution isomers, are often difficult to obtain in good yields, and purification by selective crystallization is usually not possible [4] .…”