Strong Color Tuning of Self‐Assembled Azo‐Derived Phosphonic Acids upon Hydrogen Bonding

This is the authors' abstract. We don't add key points for this paper.

The unexplored combination of a hydroxy‐ gem ‐bisphosphonic (HBP) unit with strongly absorbing azo dyes leads to the formation of a glassy material with unusual black color. Strong intermolecular hydrogen‐bonding interactions combined with extensive charge transfer are proposed from spectroscopic and mass spectrometry analyses performed in solution and on thin films. Dramatic color switch from blue gray/green to orange is obtained by varying the hydrogen‐bonding acceptor character of the solvent or substrate, thereby paving the way to tunable colored materials using HBP‐functionalized π‐conjugated molecules.