Synthesis and structure of diethylaluminum malonate: An unusual hexanuclear aluminum complex with malonate trianion ligands

Reaction of malonic acid with Et3Al results in the formation of the hexanuclear aluminum compound Et12Al6[CH(COO)2]2(THF)2 (1) containing malonate trianion ligands. Molecular studies showed that the centrosymmetric molecule of 1 consists of a tricyclic structure formed by a central four-membered Al2O2 ring and two six-membered AlO2C3 rings. All the aluminum atoms are four-coordinate. The compound showed low activity as an initiator of ɛ-caprolactone polymerization.

Graphical abstractReaction of malonic acid with Et3Al results in the formation of the hexanuclear aluminum compound Et12Al6[CH(COO)2]2(THF)2 (1) containing malonate trianion ligands.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Et3Al reacts with malonic acid yielding Et12Al6[CH(COO)2]2(THF)2 (1). ► The compound contains two malonate trianion ligands. ► A molecule of 1 consists of a central Al2O2 ring and two 6-membered AlO2C3 rings.