Unexpected Polymerization of Carbamate-Bridged {Al3(μ3−O)}7+ Complex Units

The literature on aluminum coordination networks so far contains data on COO-bridged derivatives exclusively. This paper addresses the question whether or not aluminum complexes, especially carbamate-bridged {Al3(μ3−O)}7+ units, can also form networks via the neutral ligand positions. Our findings show that a highly unexpected polymerization of the aluminum carbamates can occur during the isolation of the initially targeted compound. Although bidentate ligands bind to the neutral ligand coordination sites as expected, they do not act as linker molecules but cause an uncontrolled networking via the carbamate ligands. One- and two-dimensional solution and solid-state NMR experiments were primarily used to investigate the coordination behavior of the ligands and to elucidate the actual obtained product.