Synthesis and characterization of calcium β-diketonate complexes. X-Ray crystal and molecular structures of: [{Ca(tmhd)2}2(18-crown-6)], [Ca(dpp)2(thf)2] and [Ca(dpp)2(triglyme)]

Abstract

Reactions of 2,2,6,6-tetramethyl-3,5-heptanedione (Htmhd), 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (Hhfa) or 1,3-diphenyl-1,3-propanedione (Hdpp) with calcium methoxide in hexane or toluene afford the corresponding known oligomeric β-diketonates: [Ca₃(tmhd)₆], [{Ca(hfa)₂}_n] and [{Ca(dpp)₂}_n]. The complexes react with tetrahydrofuran, 2,5,8,11-tetraoxadodecane (triglyme) or 1,4,7,10,13,16-hexaoxacyclooctadecane (18-crown-6) leading to the formation of the new mononuclear [Ca(dpp)₂(thf)₂], [Ca(dpp)₂(triglyme)] and dinuclear [{Ca(dpp)₂}₂(18-crown-6)] and [{Ca(tmhd)₂}₂(18-crown-6)] adducts. The obtained complexes were characterized by elemental analyses, IR, ¹H and ¹³C NMR spectroscopies; moreover, single crystal X-ray diffraction measurements were also carried out for: [{Ca(tmhd)₂}₂(18-crown-6)], [Ca(dpp)₂(thf)₂] and [Ca(dpp)₂(triglyme)].