Chiral Induction in Aluminum Oxo Sulfate Helical Chains

Chiral inorganic-organic hybrid complexes have fascinating structures and potential functions. The synthesis of homochiral crystals with designable and tunable compositions has attracted great interest. In this work, we investigated a series of chain-like aluminum oxo sulfate complexes and realized their structural control and chiral resolution. We synthesized a linear chain constructed from all-inorganic ligands for the first time. Subsequently, inorganic-organic hybrid helical chains were obtained by adding propionic acid with spatially oriented alkyl chains. Further, we used R/L-mandelic acid as a chiral inducer to induce the resolution of this racemic helical chain. As a result, a pair of homochiral enantiomeric helical chains was successfully resolved. Their circular dichroism spectra and second harmonic generation were investigated. This work enriches the aluminum oxo sulfate family and provides an interesting strategy for designable chirality induction in inorganic-organic hybrid complexes.