Hydrogen bonded-directed pure organic frameworks based on TTF-tetrabenzoic acid and bipyridine base

Abstract

Although MOFs and HOF based on X-shaped tetracarboxylic acid with tetrathiafulvalene (H4L) have been synthesized, the acid-base system of the ligand H4L has not reported. In this research, hydrogen-bonded organic frameworks based on H4L with difference bipyridine base (bipy and bipy-ete) were constructed. The deprotonated forms of H4L could act as hydrogen-bond donors or acceptors depending on the deprotonated carboxyl groups. One salt [H2L]2−[bipy-H2]2+H2O [bipy = 4,4′-bipyridine] 1 and one co-crystal [H4L][bipy-ete] [bipy-ete = trans-1,2-bis(4-pyridyl)ethane], 2, have been synthesized and full characterization. Compound 1 and 2 showed excellent and reproducible photocurrent response. The current response of 2 was larger than that of 1. These results open a new method to design HOFs materials based on TTF, which could act as a potential material to be used in the electro-optic field.