| 초록 |
As a mimic of bacterial light harvesting antenna complexes, a series of dendritic multiporphyrin arrays, nPZn-PFB (n = 2, 4; conically shaped dendrimers, n = 8, 16; star shaped dendrimers), were synthesized and unambiguously characterized by 1H NMR and MALDI-TOF-MS spectroscopy. Photo-induced energy transfer efficiency (ΦENT) was evaluated by fluorescent lifetime as well as the steady state fluorescent measurement. The efficiency of energy transfer from photo excited PZn units to energy accepting free base porphyrin (PFB) of star shaped dendrimers, 8PZn-PFB and 16PZn-PFB, was larger than those of the conically shaped dendrimers, 2PZn-PFB and 4PZn-PFB, respectively. On the other hand, ultrafast coherent dynamics of dendrimers were measured by femto second order fluorescent anisotropy decay observation. Very interestingly, dendritic multiporphyrin arrays exhibited quantum beat oscillations in optical anisotropy of B-band fluorescence, where larger amplitude of the oscillation was observable in star shaped and larger dendrimers, indicting the cooperative transduction of excited energy of PZn units. |
