W BAND EPR SPECTRA OF SEMIQUINONES

半醌自由基的甚高频EPR（95 GHz）谱 报告了冷冻溶液。 在这个频率下，增加的塞曼 相互作用很容易解决的各向异性分量的 g矩阵 自由基-溶剂相互作用在以下方面很重要： 了解g矩阵的结构变化。 我们已经使用 各种极性和非极性溶剂，以产生 半醌自由基从各种醌，并已测量 g-各向异性 在大多数情况下，超精细分裂仍然存在 即使在氘代溶剂中也无法解析。 G矩阵的比较 在不同溶剂中的半醌自由基是相当重要的， 已知氢键对 g矩阵的具体组成部分。 因此氢键的作用 在半醌自由基形成过程中， 了解它们在体内系统中的形成。 有 g矩阵各组成部分变化的一致趋势 关于溶剂的性质和结构。 这些 趋势可以根据SCF-MO（从头算和 半经验）计算的g张量，这表明， g-张量对氢键和离子对形成都敏感。 这些计算变得更加准确和有效， 今年的赠款。 这是一个持续多年的项目。

Very high frequency EPR (95GHz) spectra of semiquinone radicals in frozen solution are reported. At this frequency, the increased Zeeman interaction readily resolves the anisotropic components of the g-matrix. The radical-solvent interactions are important in understanding the structural variations in the g-matrix. We have used a variety of solvents, both polar and nonpolar, to generate semiquinone radicals from various quinones and have measured the g-anisotropy. For the most part, the hyperfine splittings remain unresolved, even in deuterated solvents. Comparison of the g-matrix of semiquinone radicals in different solvents is quite important and hydrogen-bonding has been known to play a remarkable effect on specific components of the g-matrix. Thus the role of hydrogen bonds during the semiquinone radical formation is of particular importance to understand their formation in in vivo systems. There are consistent trends in the variation of the components of the g-matrix with respect to the nature of the solvents and structure. These trends can be understood in the light of SCF-MO (both ab initio and semi-empirical) calculations of the g-tensor, which show that the g-tensor is sensitive to both hydrogen bonding and ion-pair formation. These computations have become much more accurate and efficient during this grant year. This is an ongoing multi-year project.