Photomechanical responses of coordination polymers regulated by precise organization of the photoactive centers

Abstract

Three photoactive Cd(II) coordination polymers (CPs), [Cd (Fsbpe)(DBBA)₂]·2DMF (CP₁), [Cd(Fepbpe)(DBBA)₂]·2DMF (CP₂) and [Cd(Fsbpeb)(DBBA)₂] (CP₃) (DBBA = 3,5-dibromobenzoic acid, DMF = dimethyl formamide) with similar 1D chain motifs exhibited completely different photosalient behaviors (PS) in response to UV light. Mechanical motion was triggered by [2+2] photocycloaddition and regulated by positioning of the photoactive alkene centers relative to the crystal axis. This solid-state reaction was reversed by heating and photomechanical behaviour was repeated over several cycles. A simple photoactuating device was prepared using a CP₃–PVA composite.