Covalently Linked 5,15‐Diazaporphyrin Dimers: Promising Scaffolds for a Highly Conjugated Azaporphyrin π System |
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| Authors: | Prof?Dr Yoshihiro Matano Daisuke Fujii Tarou Shibano Prof?Dr Ko Furukawa Tomohiro Higashino Prof?Dr Haruyuki Nakano Prof?Dr Hiroshi Imahori |
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| Institution: | 1. Department of Chemistry, Faculty of Science, Niigata University, Niigata 950‐2181 (Japan);2. Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo‐ku, Kyoto 615‐8510 (Japan);3. Center for Instrumental Analysis, Institute for Research Promotion, Niigata University, Nishi‐ku, Niigata 950‐2181 (Japan);4. Department of Chemistry, Graduate School of Sciences, Kyushu University, Fukuoka 812‐8581 (Japan);5. Institute for Integrated Cell‐Material Sciences (WPI‐iCeMS), Kyoto University, Nishikyo‐ku, Kyoto 615‐8510 (Japan) |
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| Abstract: | The first examples of β–β directly linked, acetylene‐bridged, and butadiyne‐bridged 5,15‐diazaporphyrin dimers have been prepared by palladium‐catalyzed coupling reactions of nickel(II) and copper(II) complexes of 3‐bromo‐10,20‐dimesityl‐5,15‐diazaporphyrin (mesityl=2,4,6‐trimethylphenyl). The effects of the linking modes and meso‐nitrogen atoms on the structural, optical, electrochemical, and magnetic properties of the distributed π systems were investigated by using X‐ray crystallography, UV/Vis absorption spectroscopy, DFT calculations, cyclic voltammetry, and ESR spectroscopy. Both the electronic and steric effects of the meso‐nitrogen atoms play an important role in the highly coplanar geometry of the directly linked dimers. The direct β–β linkage produces enhanced π conjugation and electron‐spin coupling between the two diazaporphyrin units. |
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| Keywords: | electrochemistry EPR spectroscopy macrocycles porphyrinoids transition metals |
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