PROTON DYNAMICS IN FREE BASE PORPHYRINS IN EXCITED SINGLET STATE

对卟啉体系内质子互变互变的兴趣 在基态和激发态都经历了重新点燃 由于选择性应用的可能性，近年来的兴趣 通过烧孔实现光激活互变构体切换。这件事有 作为一种数据存储方式的潜力将远远 比目前的光存储系统高出几个数量级。 此外，在生物系统中，质子在酶中的转移 反应和跨膜“质子动力”的建立 武力“仍然是一个积极努力的领域。以前的ESR实验 表明质子在低温下运动。 我们现在正在检验这一假说，我们正在专门检验 蛋白质在调节质子转移反应中的作用。 因为互变异构化反应会改变荧光 各向异性，时间分辨荧光测量使我们能够 测量发生在单线态的质子转移速率。 对于激发单重态，卟啉的各向异性衰减 细胞色素c固定在粘性溶液中表明 质子转移速率约为2毫微秒。

The interest in the inner proton tautomerism of porphyrin systems in both the ground and excited states has experienced a rekindled interest in recent years due to the possibility of applying selective photoactivated tautomer switching via hole burning. This has the potential of serving as a modality for data storage that would far exceed current optical storage systems by several orders of magnitude. Moreover, in biological systems, the transfer of protons in enzymatic reactions and for the establishment of transmembranous "protonmotive force" remains an area of active endeavor. Previous ESR experiments suggest that that the protons are moving at cryogenic temperatures. We are now examining this hypothesis and we are specifically examining the role of the protein in modulating the proton transfer reaction. Since the tautomerization reaction will change the fluorescence anisotropy, time resolved fluorescence measurements allow us to measure the proton transfer rates that occur in the singlet state. For the excited singlet state, the decay of anisotropy for porphyrin cytochrome c immobilized in a viscous solution indicates that the proton transfer rate is about 2 nsec.