Doubling the Length of the Longest Pyrene-Pyrazinoquinoxaline Molecular Nanoribbons.

Molecular nanoribbons are a class of atomically-precise nanomaterials for a broad range of applications. An iterative approach that allows doubling the length of the longest pyrene-pyrazinoquinoxaline molecular nanoribbons is described. The largest nanoribbon obtained through this approach-with a 60 linearly-fused ring backbone (14.9 nm) and a 324-atoms core (C 276 N 48 )-shows an extremely high molar absorptivity (values up to 1 198 074 M -1  cm -1 ) that also endows it with a high molar fluorescence brightness (8700 M -1  cm -1 ).