Synthesis of mixed-ligand alkali earth element dipivaloylmethanates with o-phenanthroline

A one-step method for the synthesis of volatile barium and strontium complexes [M(Thd) 2 (Phen) 2 ] (M = Ba, Sr; Thd is the dipivaloylmethane anion) was developed. The method is based on the reaction of metal hydroxide octahydrates with dipivaloylmethane (HThd) and o -phenanthroline (Phen) accompanied by removal of water from the reaction mixture as a solvent-water azeotrope. In the case of calcium hydroxide monohydrate, a similar interaction causes destruction of the dipivaloylmethanate ligand to give a mixed-ligand calcium complex with the pivalate anion and o -phenanthroline.