Development of Frequency Swept EPR under the Low Magnetic Field

利用电子顺磁共振（EPR）和振动拉曼光谱（Raman）两种技术进行了合作研究，得到了以下结果。对于EPR，我们与四个实验室合作，分别是柏林自由大学的moebius教授、意大利帕多瓦大学的corvaja教授、耶路撒冷希伯来大学的levanon教授和德国弗莱堡大学的kothe教授，我们在那里进行了实验和讨论。为了拉曼，温诺博士参观了钱皮恩教授的实验室。他在波士顿东北大学做了两个星期的实验。在金属（Zn和Mg）卟啉-氮氧化物自由基体系中，我们首次用EPR技术观察到激发的重态和四重奏态，它们通过高频（95 GHz） EPR.2很好地分离。利用金属卟啉和-酞菁首次在+90℃的溶液中观察到激发态的EPR信号。从光谱模拟中，分析了Jahn-Teller分裂态的平均和分子运动，表明该方法对分析溶液中激发态三重态的性质是非常有用的。建立了二维脉冲EPR技术来测定激发态的自旋多重性，并将其应用于双自由基连接富勒烯体系的研究。在激发时，首次观察到并确定了激发五态，并对电子结构进行了分析。对氧合细胞色素P450进行了共振拉曼研究，并在活性位点成功地分配了一个结构标记带。Fe-O-O弯曲模式的观察揭示了酶的结构特异性。

Collaborative studies were made by use of two techniques, electron paramagnetic resonance(EPR) and vibrational (Raman) spectroscopy, giving the following results.For EPR, we collaborated with four laboratories, Prof.Moebius's at Free University of Berlin, Prof.Corvaja's at Padova University in Italy, Prof.Levanon's at Hebrew University of Jerusalem, and Prof.Kothe's at Freiburg University in Germany, where we made the experiments and discussion. For Raman, Dr.Unno visited Prof.Champion's lab. at Northeastern University of Boston and ran experiments for two weeks.1. In a system of metallo(Zn and Mg) porphyrin-nitroxide radical, we observed excited doublet and quartet states for the first time by EPR techniques, which are separated nicely by means of high frequency (95 GHz) EPR.2. EPR signals of the excited triplet states were observed for the first time in solution using metallo-porphyrins and -phthalocyanines up to +90℃. From the spectral simulation, averaging over the Jahn-Teller split states and molecular motions were analyzed , which indicates that this method is very useful for analyses of excited triplet properties in solution.3. Two dimensional (2D) pulsed EPR techniques were developed to determine spin multiplicity of the excited multiplet states and applied to studies in systems of bisradical linked fullerene. On excitation the excited quintet states were observed and definitely assigned for the first time and the electronic structures were analyzed.4. The resonance Raman investigation was made for oxygenated cytochrome P450 and a structural marker band was successfully assigned at the active site. The observation of the Fe-O-O bending mode reveals structural specificity of the enzyme.