Abstract
Photochemical behavior was observed for 1,3,6,8-tetrakis(N-methylpyridinium-4-yl)pyrene (Py^<4+>)/clay complexes and Py^<4+>/tetrakis(1-methylpyridinium-4-yl)porphyrin (p-TMPyP)/clay complexes. Py^<4+> exits as monomer without excimer formation on the clay surface. While S_0-S_1 transition of non-substituted pyrene is forbidden, Py^<4+> exhibited an allowed S_0-S_1 transition. Judging from steady and time-resolved fluorescence spectra, energy transfer from excited Py^<4+> to p-TMPyP on the clay surface was successfully achieved. The efficiency reached up to 87% when the Py^<4+> and p-TMPyP loading-level versus cation exchange capacity of the clay was 2.5%. Such high efficiency was caused by (1) high fluorescence quantum yield of Py^<4+>, (2) controlled intermolecular distance between Py^<4+> and p-TMPyP, and (3) suitable adsorption structure of Py^<4+> and p-TMPyP molecules such as integration on the clay surface.
