Semenov Valentin A, Martin Gary E, Krivdin Leonid B
A.E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia.
Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey, USA.
Magn Reson Chem. 2023 May;61(5):301-305. doi: 10.1002/mrc.5334. Epub 2023 Feb 13.
Early NMR studies of several heterohelicenes containing an annular nitrogen atom and a thiophene ring in their structure suggested the possibility of the lengthening of the carbon-carbon bonds in the interior of the helical turn of the molecule based on the progressive more shielded nature of C resonances toward the center of the helical turn. Computational chemistry capabilities when those NMR studies were performed were primitive in comparison to what is now possible. We now report the optimized geometry and a comparison of the calculated versus observed H and C NMR chemical shift assignments for [1]benzothieno[2,3-c]naphtho[1,2-f]quinoline that confirms these suspicions.
早期对几种结构中含有环状氮原子和噻吩环的杂螺旋烯的核磁共振研究表明，基于碳共振向螺旋圈中心逐渐增强的屏蔽性质，分子螺旋圈内部的碳 - 碳键有可能变长。与现在的情况相比，进行这些核磁共振研究时的计算化学能力还很原始。我们现在报告了[1]苯并噻吩并[2,3 - c]萘并[1,2 - f]喹啉的优化几何结构，以及计算得到的与观测到的氢和碳核磁共振化学位移归属的比较，这证实了这些推测。
