Convex and Concave Encapsulation of Multiple Potassium Ions by Sumanenyl Anions

Abstract

Herein we report the novel complex consisting of di- and tripotassiumsumanenide, K7(C21H10(2-))2(C21H9(3-))·8THF (2), which was prepared by the treatment of sumanene (C21H12, 1) with excess K metal in THF. The X-ray structural determination revealed unique self-assembly of six potassium ions sandwiched by convex faces of two sumanenyl trianions in addition to novel interaction involving all 15 carbon atoms of three Cp-like moieties on the concave surface of the sumanenyl bowls outside the sandwich. The unique structural features of 2 are rationalized with the help of DFT calculations.