Occurrence of the solid-state photo-CIDNP effect at earths magnetic field

1994年，Zysmilich和McDermott发现了固态光-CIDNP效应，该效应已被证明存在于几种电子转移蛋白质中，如光合作用反应中心(RCS)，并允许核磁共振信号的极大增强。这种效应的发生和强度强烈地依赖于磁场强度。到目前为止，这种效应只在核磁共振磁体内部可用的高场下进行了研究。在这里，我们想要开发和应用MAS-核磁共振穿梭系统，以允许在磁铁外部感应效应和在磁铁中心进行核磁共振测量。因此，所提出的航天飞机系统将结合低场的优势，即高的核自旋极化，和高场的优势，即高化学位移色散。这样的系统将允许对电子结构进行详细研究，发现更多显示这种效应的系统，并将允许探索目前理论的有效性。该理论还预测了在包括地球磁场条件在内的弱磁场中发生这种效应。有了先进的航天飞机系统，使用微弱的对应场，这一理论预测将得到验证。特别是，我们感兴趣的是地球磁场对光合作用反应中心蛋白质和蓝光感受器的影响。在地球磁场的反应中心发生的这种效应将表明有效电子转移的核自旋超极化的功能关联。对蓝光感光器的成功实验将强化这样一种观点，即动物导航中依赖光的磁感应依赖于磁场依赖的化学反应。因此，理想情况下，我们的实验将为光合作用中的生物自旋电子自旋阀以及控制动物导航的电子-电子-核自旋动力学提供一些实验证据。

The solid-state photo-CIDNP effect, discovered in 1994 by Zysmilich and McDermott, has been shown to occur in several electron-transfer proteins such as photosynthetic reaction centers (RCs) and allows for enormous enhancement of NMR signals. Occurrence and strength of the effect strongly depend on the magnetic field strength. Up to now, the effect has been studied exclusively at the high fields available inside NMR magnets. Here we want to develop and apply a MAS-NMR shuttle system to allow for induction of the effect outside the magnet and NMR measurement in the center of the magnet. Hence, the proposed shuttle system will combine the advantage of low fields, i.e., high nuclear spin-polarization, with the advantage of high field, i.e. high chemical shift dispersion. Such system will allow for detailed studies on electronic structures, discovering more systems showing the effect and it will allow to explore the validity of the present theory.Theory also predicted the occurrence of the effect at weak magnetic fields including earths magnetic field conditions. With an advanced shuttle system, using a weak counter field, this theoretical prediction will be tested. In particular, we are interested in earths magnetic field effects on photosynthetic reaction center proteins and blue-light photoreceptors. Occurrence of the effect in reaction centers at earths field would suggest a functional relevance of nuclear spin-hyperpolarization of the efficient electron transfer. A successful experiment on blue-light photoreceptors would strengthen the proposal that light-dependent magnetoreception in animal navigation relies on magnetic-field dependent chemical reactivity. Hence, ideally our experiments will provide some experimental evidence on a bio-spintronic spin-valve in photosynthesis and on electron-electron-nuclear spin-dynamics controlling animal navigation.