Pr) 2 (b-ketoesterate)] 2 derivatives are asymmetrically substituted dimers with one octahedrally and one tetrahedrally substituted aluminum atom, bridged by two isopropoxo groups, whereas the Al(b-ketoesterate) 3 derivatives are monomers with octahedrally coordinated aluminum. Transesterification as a possible side reaction was only observed at elevated temperatures for Al(tert-butyl acetoacetate) 3 in the presence of liberated iso-propanol.

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Depending on the reaction conditions, different aluminium dialkylmalonate derivatives were obtained by reaction of aluminium alkoxides Al(OR)3 (R = Et, iPr, tBu) with dialkylmalonates, viz. Al(malonate)3 (malonate = dimethyl, diethyl, di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)4(malonate)2 (malonate = di-iso-propyl and di-tert-butyl malonate), Al2(OiPr)2(di-iso-propylmalonate)4 and Al3(OH)(OEt)3(diethylmalonate)5. All compounds were characterized by NMR spectroscopy, and single crystal structure analyses are reported for each type of compound. An Al2(OiPr)2(dialkylmalonate)4 derivative was only obtained by disproportionation of Al2(OiPr)4(di-iso-propylmalonate)2, but not by reaction of Al(OiPr)3 with dialkylmalonates in the corresponding molar ratio. Reactions of Al(OtBu)3 only resulted in Al(malonate)3 derivatives, but no transesterification was observed, contrary to the reaction of Al(OiPr)3 with dimethyl or diethyl malonate.Graphical abstract

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Graphical abstractA series of new yttrium alkoxo/hydroxo/oxo clusters, with different structural motifs, was obtained by reaction of Y5O(OiPr)13 with isopropyl acetoacetate (iprac-H), viz. Y9O(OH)9(OiPr)8(iprac)8, Y4(OH)2(iprac)10, Y6(OH)6(iprac)12 and Y9O(OH)9(iprac)16.Highlights► Different cluster compounds are formed when the Y5O(OiPr)13:isopropyl acetoacetate ratio is changed. ► The structural motif of an oxygen-centered square pyramid of five Y atoms is retained in some of the clusters. ► Part of the clusters can be transformed in other cluster types.