α-Oligofurans show a sizeable extent of π-conjugation as probed by Raman spectroscopy

A Raman spectroscopic analysis revealed that pi-conjugation does not reach saturation at least up to the octamer in long alpha-oligofurans and spreads over 14-15 furan units in the polyfuran. Comparing DFT calculations with experimental results suggests that a considerable amount of HF exchange is required to reproduce computationally the observed conjugation.