A Polyaromatic Metallotube With a Dual Multi‐Functionalization Ability

Abstract Post‐functionalization is an advanced, key synthetic method in supramolecular systems, whereas the previous method relies heavily on the substitution on the organic frameworks. Here we report a polyaromatic metallotube capable of dually multi‐functionalizing the metal sites in an efficient post‐assembly fashion. The Pt(II)‐linked tube with tetrachloro groups is prepared from two PtCl 2 hinges and two bent bispyridine ligands in high yield. The new metallotube efficiently converts to tetra‐substituted tubes by the first multiple functionalization, through the replacement of the chloro groups with various alkynyl groups. The tubular structures before/after the functionalization are unequivocally confirmed by X‐ray crystallographic analysis. A resultant tetraammonium‐attached Pt(II)‐tube exhibits high water solubility and uptake abilities toward spherical and rod‐like compounds. The metallotube strongly binds one molecule of fullerene C 60 in the polyaromatic cavity yet releases it through the second multi‐functionalization by tetrabromination of the metal hinges in a quantitative and reversible manner. Even after Bingel reaction within the tube, sterically demanding bis‐substituted fullerenes (>∼80% selectivity) are readily released by the second functionalization. The present method, i.e., the use of simple PtCl 2 hinges, will be applicable to wide‐ranging metallo‐supramolecules to enhance their structural and functional versatilities via post‐multi‐functionalizations.