Lithium ion-selective binding properties of a conformationally constrained tris(spirotetrahydrofuran) secured to an inositol orthoformate platform

(equation presented) The C_3v-symmetric triaxially locked trispirotetrahydrofuran 2 binds Li⁺ ions strongly and Na⁺ ions much less effectively. The observed discrimination factor is attributed to greater structural preorganiztion and lower solvation prior to selective complexation, and particularly to the formation of a 2:1 sandwich complex involving lithium. ¹³C NMR studies have defined a reluctance to form a 1:1 species when excess Li⁺ is present.