Photoactuation Effects in Isotypical Zn(II) Benzoate Complexes with Difluoro-Substituted 4-Styrylpyridines

Here, we investigated photoreactivity and photosalient effects of isotypical Zn(II) paddle wheel complexes through a new difluoro-substituted 4-styrylpyridine (4spy). Interestingly, substitution of F at 4spy showed a tremendous change in photoreactivity as well as the rate of photoresponsive nature. For two different [Zn2(benzoate)4L2] complexes, 1 = [Zn2(benzoate)4(35F-4spy)2], 2 = [Zn2(benzoate)4(23F-4spy)2], solid-state [2 + 2] cycloaddition reaction studies are discussed in detail. 4spy ligands are aligned in a head-to-tail fashion and can result in a photosalient effect, leading to the formation of 1D CPs. An overall increase in the percentage cell volume of 15% and 16% for 1 and 2, respectively, during the photoreaction appears to indicate a significant anisotropic expansion is responsible for the photomechanical effects and finally the photosalient effect (PSE). At molecular level F atom increase of the ligand and a suitable crystal structure to attain [2 + 2] CAR, photosalient effect are studied in detail with different size and shape of crystals. Based on our current study and results of the crystal PSE, we are able to order the PSE nature of these isotypical complexes: 2 > 1.