Department of Organic Chemistry, University of Pavia, Viale Taramelli, 10, 27100, Pavia, Italy.
Org Biomol Chem. 2010 Jul 21;8(14):3272-80. doi: 10.1039/c004379f. Epub 2010 Jun 4.
A series of four chiral D(2) symmetrical macrocycles, in which two 3,3'-disubstituted Binol units are bridged by conjugated organic spacers of differing lengths and/or electronic properties, have been synthesized and characterized. The four different bridges consist of either ether or ester linkages in combination with either short biphenyl spacers or long diethynylphenyl spacers. NMR, CD spectroscopy, and molecular modeling help rationalize the shape of the cyclic scaffolds and even subtle modifications in the bridging units lead to drastic changes in conformation. The three macrocycles with longer bridging units and/or ester linkages form stable 1 : 1 complexes with C(60) in toluene. The one with a short spacer and ether linkage does not. The binding constants have been determined with a high degree of accuracy via equilibrium-restricted factor analysis; with long spacers and ester linkages log K(a) = 4.37(2); with short spacers and ester linkages log K(a) = 3.498(4); with long spacers and ether linkages log K(a) = 3.509(2).
已经合成并表征了一系列四个手性 D(2)对称的大环，其中两个 3,3'-取代的联萘单元通过不同长度和/或电子性质的共轭有机间隔物桥接。这四个不同的桥由醚或酯键结合短联苯间隔物或长二乙炔基苯间隔物组成。NMR、CD 光谱和分子建模有助于解释环状支架的形状，即使在桥接单元中进行细微的修饰也会导致构象发生剧烈变化。具有较长桥接单元和/或酯键的三个大环在甲苯中与 C(60)形成稳定的 1:1 配合物。具有短间隔物和醚键的大环则不能。通过平衡限制因子分析以高精度确定了结合常数；长间隔物和酯键的 log K(a) = 4.37(2)；短间隔物和酯键的 log K(a) = 3.498(4)；长间隔物和醚键的 log K(a) = 3.509(2)。
