Oxygen-Doped Zig-Zag Molecular Ribbons.

The synthesis of a zig-zag oxygen-doped molecular rhombic ribbon has been achieved. This includes oxidative C-C and C-O bond formations that allowed the stepwise elongation and planarization of an oxa-congener of 2,7-periacenoacene. X-ray diffraction analysis corroborated the flat structure and the zig-zag topology of the O-doped edges. Photophysical and electrochemical investigations showed that the extension of the peri-xanthenoxanthene (PXX) into the molecular ribbon induces a noticeable shrinking of the molecular band gap devised by a rising of the HOMO energy level, a desirable property for p-type organic semiconductors.