Development of Catalytic Process for Photooxidation with Fluorinecontaining Molecules and Their Assemblies

1)在紫外光照射下，以铑负载的全氟聚乙烯（rho-phenylene）成功地将水分子光解成二氢和羟基自由基。在反应体系中，水分子单电子氧化形成的羟基自由基被苯分子捕获，生成苯酚。系统中H_2的析出量是由苯酚生成量和反应化学计量学预测的一半。这是由于全氟多聚（红苯基）通过其自由基阴离子分解和苯还原时消耗电子所致。分子轨道计算表明，水分子与氟化苯环相互作用，表明吸引相互作用在水的光氧化中起重要作用。2)为了揭示全氟低聚苯乙烯作为光催化剂对水进行光氧化的机理，进行了激光闪光裂解实验。全氟低聚（铑-苯基）的激发态很容易通过系间交叉转化为三重态。提出了全氟低聚（铑-苯基）的三重态被氧化猝灭，转化为阳离子自由基，作为水分子的氧化种。3)对部分氟化低聚（红-苯基）的循环伏安法测定表明，随着氟化程度的增加，还原电位和氧化电位向正极移动。4)合成了八氟非那嗪。这种化合物在可见光照射下引起水的单电子氧化。

1) We succeeded in photo-splitting of water molecule into dihydrogen and hydroxyl radical with Rh-supported perfluoropoly (rho-phenylene) under UV irradiation. Hydroxyl radical formed via one-electron oxidation of water molecule is captured by benzene molecule in the reaction system, resulting in formation of phenol. The amount of H_2 evolved in the system is half of that expected from the amount of phenol formed and the reaction stoicheometry. It is due to consumption of electrons in the decomposition of perfluoropoly (rho-phenylene) through its radical anion and reduction of benzene. Molecular orbital calculations show that a water molecule interacts with fluorinated phenylene ring, suggesting an important role of the attractive interaction in the photooxidation of water.2) Laser flash photlysis was carried out in order to reveal the mechanism of photooxidation of water with perfluorooligo (rho-phenylene) as a photocatalyst. The excited state of perfluorooligo (rho-phenylene) is readily converted to triplet stated through intersystem crossing. It is proposed that the triplet state of perfluorooligo (rho-phenylene) is oxidatively quenched to be converted to its cation radical, which acts as an oxidizing species of water molecule.3) The cyclic voltammetry measurements of partially fluorinated oligo (rho-phenylene) have shown that the reduction and oxidation potentials shifts to the positive side with increase in the degree of fluorination.4) Octafluorophenazine was sythesized. This compound induces one-electron oxidation of water under visible light irradiation.