suppression of both the crown ring and one of the two sidearms based on complexation with the metal cation. The selectivity for alkaline earth metal cations was highly dependent on the fitness of the host cavity and the guest size. Although most of the fluorophores did not respond to alkali metal cations, only trans-7a containing an 18-crown-6 ring showed K+ selectivity.
在两个侧臂的每个末端均具有having部分的两种类型的双联套索醚衍
生物,(3 x +1)-crown- x衍
生物1(x = 5),2(x = 6)和3(x = 4 )(A型)和3y-crown-y导数,6(y = 5)和7(y合成了== 6)(B型),并通过荧光光谱检查了它们对碱
金属和碱土
金属阳离子的络合行为。metal准分子发射减少,伴随着
金属离子络合的单体发射增加。该发现归因于通过基于与
金属阳离子的络合对冠环和两个侧臂之一的运动抑制,两个pyr环的空间距离的变化。碱土
金属阳离子的选择性高度取决于宿主腔的适合度和客体大小。虽然大部分荧光团并没有碱
金属阳离子反应,只是反式-图7a含有
18-冠-6环表明ķ +选择性。