卟啉-醌体系在宽光学范围内的波长分辨光诱导自旋极化
Wavelength-Resolved Photoinduced Spin Polarization in a Broad Optical Range for a Porphyrin-Quinone System
AI总结：
该研究针对卟啉-醌体系，在350-800 nm宽范围开展波长分辨光诱导核极化研究，发现其响应呈非单调依赖，确立激发波长为独立控制参数，为相关超极化研究提供方法框架。
AI中文摘要：
液态给体-受体体系中的光化学诱导动态核极化（photo-CIDNP）通常仅在有限数量的激发波长下开展研究，致使其光谱依赖性未得到完整表征。明晰photo-CIDNP的波长依赖性，对阐明潜在的自旋化学机制以及优化化学和生物相关分子体系中的超极化策略均具有重要意义。本研究针对四苯基卟啉-1,4-苯醌给体-受体体系，探究其在350-800 nm光谱范围内的波长分辨photo-CIDNP，采用可调谐激光系统和配备可更换10 nm干涉滤光片的宽带氙灯，测量了光子通量归一化的CIDNP振幅。CIDNP响应呈现出对激发波长的非单调依赖性：在350 nm附近及500-550 nm区域观测到显著的超极化，而在强吸收的400-450 nm范围内激发时，CIDNP响应大幅降低。与紫外-可见吸收光谱的对比表明，photo-CIDNP效率并非仅由光吸收决定，而是反映了波长依赖性的光物理过程。经激发光子通量归一化后，基于灯和激光的测量结果一致，验证了宽带滤波激发是波长分辨photo-CIDNP研究中可靠且易于实现的实验方法。这些结果确立了激发波长作为液态photo-CIDNP的独立控制参数，并为系统研究波长依赖性自旋超极化提供了框架。
英文摘要：
Photochemically induced dynamic nuclear polarization (photo-CIDNP) in liquid-state donor-acceptor systems is typically studied at a limited number of excitation wavelengths, leaving its spectral dependence incompletely characterized. Understanding the wavelength dependence of photo-CIDNP is important both for elucidating the underlying spin-chemical mechanisms and for optimizing hyperpolarization strategies in chemically and biologically relevant molecular systems. Here, we investigate wavelength-resolved photo-CIDNP in a tetraphenylporphyrin-1,4-benzoquinone donor-acceptor system over the 350-800 nm spectral range. Photon-flux-normalized CIDNP amplitudes were measured using both a tunable laser system and a broadband xenon lamp equipped with interchangeable 10 nm interference filters. The CIDNP response exhibits a non-monotonic dependence on excitation wavelength. Pronounced hyperpolarization is observed near 350 nm and in the 500-550 nm region, whereas excitation within the strongly absorbing 400-450 nm range results in a substantially reduced CIDNP response. Comparison with the UV-Vis absorption spectrum demonstrates that photo-CIDNP efficiency is not governed solely by optical absorption and reflects wavelength-dependent photophysical processes. After normalization to the excitation photon flux, lamp- and laser-based measurements yield consistent CIDNP results, validating broadband filtered excitation as a reliable and experimentally accessible approach for wavelength-resolved photo-CIDNP studies. These results establish excitation wavelength as an independent control parameter for liquid-state photo-CIDNP and provide a framework for systematic investigations of wavelength-dependent spin hyperpolarization.
