Fluorine-19 nuclear magnetic resonance study of the inclusion of fluoro- and difluoro-trans-cinnamates by α-cyclodextrin
作者:Ian M. Brereton、Thomas M. Spotswood、Stephen F. Lincoln、Evan H. Williams
DOI:10.1039/f19848003147
日期:——
19 F n.m.r. studies of the inclusion of o-, m-, p- and α-fluoro-trans-cinnamates and o, p- and α,p-difluoro-trans-cinnamates by α-cyclodextrin (αCD) have shown that two inclusion equilibria [graphic omitted] are established in D2O solution at pD = 8.5 ± 0.1. Typically at 294 K, K1= 111 ± 13 dm3 mol–1 and K2= 23 ± 2 dm3 mol–1 for α,p-difluoro-trans-cinnamate. Chemical-shift and other data indicate that
19个 19 F核磁共振纳入研究ø - ,米- , p -和α -氟-反式-cinnamates和邻,对-和α, p -二氟反-cinnamates由α环糊精( α CD)已经表明在p 2 = 8.5±0.1的D 2 O溶液中建立了两个夹杂物的平衡点(省略了图示)。通常在294 K, ķ 1 = 111±13分米3摩尔-1和ķ 2 = 23±2分米3摩尔-1为α,对-二氟-反肉桂酸酯。化学位移和其他数据表明,主要的S· α CD复杂的是,在其中氟代的羧酸酯基进入的宽端α CD空腔,由十二仲羟基划定,第一。的S·(α CD)2配合物可能具有其中氟的结构的反式-肉桂酸酯是由两个包封α CD与它们的空腔的紧邻的宽端部。