Modular assembly of azo photo-switches using click chemistry allows for predictable photo-behaviour

• Azobenzene chromophores can be difficult to make with desired photoswitching behaviour and chemical functionality.
• Click chemistry allows for easy tailoring of molecular structure.
• Azos made using click chemistry retain absorbance and isomerization behavior regardless of the added chemical substituents.
• This provides an easy way to tailor structure while retaining desired photoswitching behaviour.

Many azobenzene-based applications rely on variations in the ‘head’ group of the chromophores. We present a method to chemically modify azobenzenes quickly and easily, and report the effects that these modifications have on the properties of the azobenzene chromophores. Using now common ‘click’ chemistry, we have developed a methodology which can be applied in a one-pot fashion to rapidly vary the molecular structure, permitting the synthesis of libraries of dyes while allowing for the retention of photophysical characteristics. We validate this synthetic approach as not changing the nature of the chromophores in our testing of 17 derivatives, indicating that this is a good strategy for easy and rapid molecular tailoring. The results of this study will facilitate the use of these versatile molecules in material science, as it renders diverse structures attainable within one day instead of standard, multi-day syntheses per chromophore.

Large families of azo photo-switches can be readily prepared by clicking designer ‘heads’ onto stock ‘bodies’: 1 step, 1 pot, 1 h; for dozens per day.Figure optionsDownload as PowerPoint slide