meso-Triazolyl-appended ZnIIporphyrins were readily prepared by CuI-catalyzed 1, 3-dipolar cycloaddi-tion of benzyl azide to meso-ethynylat-ed ZnII-porphyrin (click chemistry). In noncoordinating CHCl3 solvent, spon-taneous assembly occurred to form tet-rameric array (3)2: from meso-meso-linked diporphyrins 3 1 and dodecameric porphyrin squares (4)4 and (5) 4 from the L-shaped meso-meso-linked tripor-phyrins 4 and 5. The structures of these assemblies were examined by 1H NMR spectra, absorption spectra, and their gel permeation chromatography (GPC) retention time. Furthermore, the struc-tures of the dodecameric porphyrin squares (4) 4 and (5)4 were probed by small- and wide-angle X-ray scattering (SAXS/WAXS) measurements in solu-tion using a synchrotron source. Excita-tion-energy migration processes in these assemblies were also investigated in detail by using both steady-state and time-resolved spectroscopic methods, which revealed efficient excited-energy transfer (EET) between the meso-meso-linked ZnII-porphyrin units that occurred with time constants of 1.5 ps-1 for(3)2 and 8.8ps-1 for (5)4.
All Science Journal Classification (ASJC) codes
- Organic Chemistry