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Synthesis of Nanometer‐Scale Porphyrin Wheels of Variable Size
Author(s) -
Hori Takaaki,
Peng Xiaobin,
Aratani Naoki,
Takagi Akihiko,
Matsumoto Takuya,
Kawai Tomoji,
Yoon Zin Seok,
Yoon MinChul,
Yang Jaesung,
Kim Dongho,
Osuka Atsuhiro
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701271
Subject(s) - porphyrin , scanning tunneling microscope , intramolecular force , spectroscopy , covalent bond , chemistry , mass spectrometry , photochemistry , crystallography , nanometre , fluorescence spectroscopy , materials science , fluorescence , nanotechnology , stereochemistry , organic chemistry , optics , physics , chromatography , quantum mechanics , composite material
Starting from 1,3‐phenylene linked diporphyrin zinc(II) complex 2ZA , repeated stepwise Ag I ‐promoted coupling reactions provided linear oligomers from 2 n ZA up to 128ZA . Of these zigzag shaped porphyrin arrays, the Ag I ‐promoted intramolecular cyclization reaction of 2 n ZA ( n =5, 6, 8, 9, 12, and 16) under dilute conditions gave the corresponding cyclic porphyrin wheels C2 n ZA ( n =5, 6, 8, 9, 12, and 16), whereas large arrays 2 n ZA ( n =24, 32, and 48) did not provide cyclic porphyrin products. These large discrete porphyrin arrays and wheels were fully characterized by means of 1 H NMR spectroscopy, MALDI‐TOF mass spectrometry, UV/Vis absorption spectroscopy, GPC‐HPLC analysis, and the scanning tunneling microscopy (STM) technique. The STM images of C12ZA and C18ZA reveal their large circular structures. In the cyclic structures of C2 n ZA in solution, however, the gradual decrease in fluorescence quantum yields and fluorescence lifetimes are observed, reflecting some conformational heterogeneities. Collectively, the present work provides an important contribution to the construction of fully covalently linked large cyclic arranged porphyrin arrays with ample electronic interactions as a model of light‐harvesting antenna.