Ultra-wideband DEER and ESEEM on metal centers

金属中心上的超宽带 DEER 和 ESEEM

• 批准号: 221296617
• 负责人: Professor Dr. Gunnar Jeschke
• 金额: --
• 依托单位: Laboratorium für Physikalische Chemie (LPC)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/221296617?language=en
• 关键词: Ultra; wideband; DEER; ESEEM; metal

Excitation bandwidths larger than 500 MHz can provide substantial sensitivity enhancements in pulse EPR experiments and have recently become feasible with arbitrary waveform excitation. In this project we will develop such approaches for two key experiments to a point where they become applicable to protein samples. To enhance sensitivity in metal-metal DEER distance distribution measurements in the nanometer range we shall rely on a combination of ultra-wideband (UWB) techniques, chirp pump pulses for modulation depth enhancement, a chirp echo observer sequence, and, for S > 1/2 metal centers such as Gd(III), pre-polarization of the central transition by population transfer from satellite transitions. Further sensitivity gain is expected from UWB echo train detection. By UWB 2D FT-EPR correlated ESEEM and 3D FT-EPR correlated HYSCORE experiments we can measure metal nuclear frequencies exceeding 100 MHz. These experiments will be extended to microcrystalline powders and glassy frozen solutions for Cu2+, VO2+, and Mn2+ centers and ultimately be tested on a binuclear Mn(III)-Mn(IV) complex that features a multiline EPR spectrum of a type that cannot be fully analyzed without additional experimental information.

大于500 MHz的激励带宽可以在脉冲EPR实验中提供显著的灵敏度增强，并且最近已经变得可行，具有任意波形激励。在这个项目中，我们将为两个关键实验开发这种方法，使其适用于蛋白质样品。为了提高在纳米范围内的金属-金属DEER距离分布测量的灵敏度，我们将依赖于超宽带（UWB）技术的组合，用于调制深度增强的啁啾泵浦脉冲，啁啾回波观测序列，以及对于S > 1/2金属中心，如Gd（III），通过从卫星跃迁的布居转移对中心跃迁进行预极化。进一步的灵敏度增益预期从UWB回波链检测。通过超宽带二维FT-EPR相关ESEEM和三维FT-EPR相关HYSCORE实验，我们可以测量超过100 MHz的金属核频率。这些实验将扩展到微晶粉末和玻璃冷冻溶液的铜2+，钒2+，锰2+中心，并最终进行测试的双核锰（III）-锰（IV）复合物，具有多线EPR光谱的类型，不能完全分析没有额外的实验信息。