Steric Control of Directional Isomerism in Dicopper(I) Helicates of Asymmetrically Substituted 2,2‘:6‘,2‘‘:2‘‘,6‘‘‘-Quaterpyridine Derivatives
作者:E. C. Constable、F. Heirtzler、M. Neuburger、M. Zehnder
DOI:10.1021/ja9623626
日期:1997.6.1
Derivatives of 2,2':6',2'':2'',6'''-quaterpyridine have been prepared which are asymmetrically substituted with alkyl groups in the 4- or 6-position and with various substituents in the 4 '-position. These ligands form dicopper- (I) double helicates which have been investigated by 1 H and 13 C NMR spectroscopic techniques. The formation of helical isomers is shown to depend on the intramolecular interactions
已经制备了 2,2':6',2'':2'',6'''-四联吡啶的衍生物,它们在 4-或 6-位被烷基不对称取代,在 4' 被各种取代基不对称取代-位置。这些配体形成二铜-(I)双螺旋体,已通过 1 H 和 13 C NMR 光谱技术对其进行了研究。显示螺旋异构体的形成取决于双螺旋的组成螺旋体之间的分子内相互作用;4'-甲基取代基与配对螺旋体的 4-取代基发生空间相互作用,导致选择性适中,尽管庞大的 4-取代基会降低选择性。在不存在 4'-取代基的情况下,较小的间距允许组分螺旋体的类似 4-取代基之间的空间相互作用。在每种情况下,