for nuclei farther from the iron ion. As a result, it is also the dominant mechanism for the relaxation of the porphyrin protons. The π spin distribution on the porphyrin ring has been derived from the dipolar contribution to the linewidth for the carbon nuclei. Furthermore, the experimental β proton resonance linewidth can be interpreted only by considering a normalized iron spin density lower than unity
高同位素氯(5,10,15,20-四苯基卟啉铁)(III)的13 C nmr光谱已使用在选定位置同位素富集的卟啉明确分配。卟啉核碳共振的意外线宽由碳核与配体不成对的π电子自旋密度的偶极相互作用解释。这种相互作用是介观弛豫的主要机制碳和吡咯β碳。对于远离铁离子的原子核,此机制的相对贡献增加。结果,它也是卟啉质子弛豫的主要机理。卟啉环上的π自旋分布是由偶极对碳核线宽的贡献得出的。此外,仅考虑低于1的归一化铁自旋密度,才能解释实验性β质子共振线宽。提出3.5 / 5的值与早期的分子轨道计算非常吻合。该分析提供了一组自洽的数据,用于定量描述对观察到的位移的各种贡献,包括以配体为中心的伪接触贡献以及对质子和碳核的线宽。
Tsukamoto, Sachiko; Kato, Hikaru; Greshock, Thomas J., Journal of the American Chemical Society, 2009, vol. 131, p. 3834 - 3835
作者:Tsukamoto, Sachiko、Kato, Hikaru、Greshock, Thomas J.、Hirota, Hiroshi、Ohta, Tomihisa、Williams, Robert M.
DOI:——
日期:——
BLANZ, JOACHIM;ZELLER, KLAUS-PETER, J. LABELL. COMPOUNDS AND RADIOPHARM., 27,(1989) N 1, C. 91-101
作者:BLANZ, JOACHIM、ZELLER, KLAUS-PETER
DOI:——
日期:——
An efficient laboratory-scale preparative method for [1-<sup>13</sup>C]glycocholic acid
A breath test using [1-13C]glycocholic acid as a substrate is a potential diagnostic method for small intestinal bacterial overgrowth syndrome. [1-13C]Glycocholic acid has been thus synthesized in an excellent yield from ethyl [1-13C]glycinate hydrochloride in a one-pot reaction. This method is suitable for the preparation of the labeled compound on a laboratory scale, which helps to perform extensive clinical studies of the breath test.