A New exTTF-Crown Ether Platform To Associate Fullerenes: Cooperative n-π and π-π Effects

A new and readily available exTTF-bis(crown ether), 1, efficiently recognizes C-60 as well as C-70 by means of cooperative pi-pi and n-pi interactions. The geometrical (concave-convex) and electronic (donor-acceptor) complementarity accounts on one hand for remarkable binding strengths, with association constants reaching 10(7) M-1 in benzonitrile, and on the other hand for lifetimes of the photogenerated radical ion pair state on the order of 45 ps.