Mechanical Bending and Modulation of Photoactuation Properties in a One-Dimensional Pb(II) Coordination Polymer

With emerging research on stimuli-responsive materials, dynamic crystals are at the forefront of investigation. However, research on the mechanical properties of coordination polymers (CPs) is still in its infancy. Elastic deformation induced by pressure, and photoactuation is a rare occurrence in CPs, let alone its combination in a single CP. Here, we report a one-dimensional CP comprising PbBr2 chains with 3-fluoro-4′-styrylpyridine arms showing excellent elasticity and photomechanical properties. A slender crystal can be bent to make a circle and write different shapes with restoration of the original shape upon removal of the applied force. In addition, photomechanical properties triggered by [2+2] cycloaddition of the olefinic ligand can be modulated easily by variation of the crystal sizes. Crystals with a bigger width show destructive photosalient effects, while the smaller ones show plastic deformation like bending, twisting, curling, etc., upon UV irradiation. This example provides an avenue for designing CPs for multistimuli-responsive actuating properties.