A Tightly Stretched Ultralong Supramolecular Multiporphyrin Array Propagated by Double-Strand Formation.

A shape-programmed linearity through supramolecular polymerization is demonstrated by a step-growth double-strand formation of a telechelic oligomeric porphyrin array in which two alternating pyridyl-porphyrin sequenced units are held together by self-complementary ligand-to-metal coordination. The stiff rod-like structure and sufficiently large binding constant of the double-strand unit considerably extended a supramolecular array in the one dimension, which produced a tightly stretched string with a length that exceeded several micrometers.