Synthesis and Characterization of Supramolecular Nanotubes of Tetraphenylethylene-Porphyrin Conjugates

A series of tetraphenylethylene-porphyrin conjugates ((TPE)nH(2)Ps, n = 1, 2, and 4) are synthesized by Lindsey condensation and Adler-Longo methods. (TPE)nH(2)Ps are structurally characterized by H-1-NMR and MALDITOF mass spectrometry, and the photophysical and electrochemical properties are analyzed by UV-Vis absorption and fluorescence spectroscopies, and cyclic voltammetry. As the number of TPE increase, the porphyrin band gaps were slightly decreased, together with a small bathochromic shift of absorption and red shift in emission bands. The theoretical DFT calculations also showed good agreement with the experimental results. From TEM observations, (TPE)(2)H2P and (TPE)(4)H2P formed nanotubes with a diameter of 10 to 20 nm and a length of about 100 nm in a chlorobenzene/n-hexane (1:1 v/v) mixture and found that the wall thickness of nanotubes increased with the number of TPE moieties.