Unlocking the Chemical and Structural Complexity of Aluminum Hydroxy Acetates: from Commodity Chemicals to Porous Materials.

Aluminum acetates have been in use for more than a century, but despite their widespread commercial applications, essential scientific knowledge of their synthesis-structure-property relationships is lacking. High-throughput screening, followed by fine tuning and extensive optimization of reaction conditions using Al, OH and CHCOO ions, has unraveled their complex synthetic chemistry, yielding for the first time the four phase pure products Al(OH)(OCCH) ⋅ x HO (x=0, 2) (1A and CAU-65, 1B), AlO(HOCCH)(OCCH) (2), and the porous aluminum salt Al(OH)(CHCOO) (CAU-55-OH, 3). Structure determination by electron and X-ray diffraction was carried out and the data suggested porosity for 1B and 3, which was confirmed by physisorption experiments. Even the scale-up to the 10 L scale was accomplished for 1A, 1B and 3 with yields of up to 1.1 kg (99 %). This study of a seemingly simple chemical system provides important information on both fundamental inorganic chemistry and porous materials.