Unconventional Lanthanoid Complexes Supported by Retro-Claisen Condensation Products of β-Triketonates

<i>β</i>-Triketonates have been recently used as chelating ligands for lanthanoid ions presenting unique structures varying from assemblies to polymers. Despite their novel complexation behaviour little is known about the stability of these molecules. Indeed, two examples of possible <i>in situ</i>retro-Claisen condensation reactions have been reported previously. To better understand this possible decomposition pathway, four new <i>β</i>-triketones were synthesised. Complexation reactions were performed for each of these molecules using different alkaline bases in alcoholic media, aiming to isolate the potentially varying ligands present in solution. The X-ray diffraction studies revealed the formation of structures where one, two, or three of the molecules involved in the retro-Claisen condensation reaction were linked to the lanthanoid centres.