Helix Sense-Selective Supramolecular Polymerization Seeded by a One-Handed Helical Polymeric Assembly

Helix sense-selective supramolecular polymerization was achieved using a one-handed helical nanotubular polymeric assembly as a seed. First, bipyridine (BPY)-appended achiral hexabenzocoronene ((BPY)HBC) was copolymerized noncovalently with chiral (BPY)HBC(S) (or (BPY)HBC(R)) at a molar ratio of 9:1, which, via the sergeants-and-soldiers effect, afforded a P-helical (or M-helical) nanotube, which was then treated with Cu(2+) to transform into structurally robust ((BPY)Cu)NT(P) (or ((BPY)Cu)NT(M)) with a Cu(2+)/BPY coordination polymer shell. Helical seeds ((BPY)Cu)NT(P) and ((BPY)Cu)NT(M) brought about the controlled assembly of fluorinated chiral FHBC(S) and FHBC(R) as well as achiral FHBC to yield one-handed helical nanotubular supramolecular block copolymers, in which the helical senses of the newly formed block segments were solely determined by those of the helical seeds employed. Noteworthy, FHBC(S) and FHBC(R) alone without the helical seeds form ill-defined agglomerates. Attempted supramolecular polymerization of a racemic mixture of FHBC(S) and FHBC(R) from ((BPY)Cu)NT(P) (or ((BPY)Cu)NT(M)) resulted in its chiral separation, affording P-helical (or M-helical) diastereomeric block segments composed of FHBC(S)and FHBC(R) with different thermodynamic properties.