cis-cyclohexyl-15-crown-5 ether: Dynamic stereochemistry in solution as studied by carbon-13 NMR techniques
作者:G. W. Buchanan、K. Bourque、G. K. Diedrich、M. Z. Khan
DOI:10.1002/mrc.1260250116
日期:1987.1
NMR spectra of cis‐cyclohexyl‐15‐crown‐5 ether in the temperature range 298–173 K have been recorded. A single degenerate conformational process, attributed to cyclohexyl ring inversion, has been detected with a barrier of ca 10.3 kcal mol‐1. Sodium ion complexation increases this barrier by ca 0.5 kcal mol−1, whereas potassium ion complexation has no measurable effect. Spin‐lattice relaxation time results
顺式环己基-15-冠-5 醚在 298-173 K 温度范围内的 13C NMR 谱已被记录。已检测到由于环己基环反转导致的单一简并构象过程,屏障为约 10.3 kcal mol-1。钠离子络合使该屏障增加约 0.5 kcal mol-1,而钾离子络合没有可测量的效果。自旋晶格弛豫时间结果也表明大环冠醚系统对钠离子的络合比钾离子更有效。