Designable Al₃₂ -Oxo Clusters with Hydrotalcite-like Structures: Snapshots of Boundary Hydrolysis and Optical...

The hydrolysis of earth-abundant Al^III has implications in mineral mimicry, geochemistry and environmental chemistry. Third-order nonlinear optical (NLO) materials are important in modern chemistry due to their extensive optical applications. The assembly of Al^III ions with π-conjugated carboxylate ligands is carried out and the hydrolysis and NLO properties of the resultant material are studied. A series of Al₃₂ -oxo clusters with hydrotalcite-like cores and π-conjugated shells are isolated. X-ray diffraction revealed boundary hydrolysis occurs at the equatorially unsaturated coordination sites of Al^III ions. Charge distribution analysis and DFT calculations support the proposed boundary substitution. The Al₃₂ -oxo clusters possess a significant reverse saturable absorption (RSA) response with a minimal normalized transmittance up to 29 %, indicating they are suitable candidates for optical limiting (OL) materials. This work elucidates the hydrolysis of Al^III and provides insight into layered materials that also have strong boundary activity at the edges or corners.