Synthesis of Mononuclear Strontium Complexes with Polyether and β‑Diketonato Ligands

Strontium β-diketonate complexes were synthesized by the substitution reaction of the bis(trimethylsilyl) amide of Sr(btsa)₂·2DME with an ethereal group and β-diketonate ligands. The compounds [Sr(tmge)(btsa)]₂ (1), [Sr(tod)(btsa)]₂ (2), Sr(tmgeH)(tfac)₂ (3), Sr(tmgeH)(acac)₂ (4), Sr(tmgeH)(tmhd)₂ (5), Sr(todH)(tfac)₂ (6), Sr(todH)(acac)₂ (7), Sr(todH)(tmhd)₂ (8), Sr(todH)(hfac)₂ (9), Sr(dmts)(hfac)₂ (10), [Sr(mee)(tmhd)₂]₂ (11), and Sr(dts)(hfac)₂·DME (12) were obtained and analyzed by various techniques, including FT-IR, NMR, TGA (thermogravimetric analyses), and elemental analysis. Complexes 1, 3, 8, 9, 10, 11, and 12 were further structurally confirmed by single-crystal X-ray crystallography, where complexes 1 and 11 showed dimeric structures with μ₂-O bonds of ethereal groups or tmhd ligands, and complexes 3, 8, 9, 10, and 12 displayed monomeric structures. Interestingly, compounds 10 and 12, which preceded trimethylsilylation of the coordinating ethereal alcohols such as tmhgeH and meeH in the presence of HMDS as by-products due to highly increasing acidity of them, originated from electron-withdrawing two hfac ligands.