Synthesis and Property of Porphyrin Complexes with Hydrogen Bond Sites

Natural porphyrin complexes are essential for life. Some compounds such as heme iron and chlorophyll have porphyrin type macrocycle as their active center. For example, heme iron is contained in hemoglobin which carries oxygen in blood, while chlorophyll absorbs light in the process of photosynthesis. As for metal porphyrin complexes, they are known that they have prominent functions including transportation of gases, activation of molecular oxygen, and electron transfer.

There are two histidine residues located in the figure. One is the proximal histidine, which is directly coordinated to iron; and the other is the distal histidine, which forms a hydrogen bond with oxygen molecule that is coordinated to iron. It has been revealed that both of them stabilize the coordination of this oxygen molecule.

We are synthesizing new porphyrin complexes with hydrogen bond sites, and it is expected that the fixation/activation of oxygen molecules will be clarified in near future.

So far a great deal of research has been done on the function of oxygen-transport, and it is considered that not only the effect of central metal and ligand but also the surrounding environment around porphyrin (within protein matrix) play important roles in those remarkable functions.

・ K. Yamanishi, T. Yairi, K. Suzuki, M. Kondo,* Chem. Commun., 2013, 49, 9296-9298. [DOI: 10.1039/c3cc44558e]

・ K. Yamanishi, M. Miyazawa, T. Yairi, S. Sakai, N. Nishina, Y. Kobori, M. Kondo*, F. Uchida

　Angew. Chem. Int. Ed., 2011, 50, 6583-6586. [DOI: 10.1002/anie.201102144]