Investigation into the role of incorporated solvent (EtOH/H₂O) molecules on the structure of group 2 metal bis(β-diketonate) complexes: ramifications for CVD precursors of electronic materials

The synthesis and characterization of thermally stable, volatile, group 2 element-containing complexes is an important prerequisite for the subsequent use of these compounds in chemical vapor deposition (CVD) of superconducting metal oxides (SMO) and other electronic materials, e.g., YBa₂Cu₃O_7-delta and CaGa₂S₄:Ce. The utilization of group 2 metal ethoxide compounds {[M(OEt)₂(EtOH)₄]_n (where M = Ca, Sr or Ba)} as precursors to additional complexes is discussed. For example, the compounds [M(tmhd)(OEt)(EtOH)]_n (Htmhd = 2,2,6,6-tetramethylheptane-3,5-dione) may be obtained by reacting one equivalent of Htmhd with the metal bis(ethoxide), and these also may be reacted further with functionalized alcohols, or a second β-diketone, to form heteroleptic compounds. Additionally, the preparation and characterization of some Lewis base adducted complexes have been examined with an emphasis on the role that water plays in their isolation.