Crystal structure and thermal behavior of some cerium complexes with the fluorinated beta-diketonate ligand 6,6,6-trifluoro-2,2-dimethyl-3,5-hexanedione (fdh)

Complexes of the type Ce(fdh)(4), M[Ce(fdh)(4)] and Ce(fdh)(3)phen were synthesized using the fluorinated beta-diketone ligand fdh = 6,6,6-trifluoro-2,2-dimethyl-3 ,5-hexanedione (phen = 1,10-ortho-phenanthroline; M = NH4, Na). The result of a synthesis depends on the stoichiometry of the edducts. The complexes are non-hygroscopic, air-stable solids. Ce(fdh)(4),Na[Ce(fdh)(4)] and phenCe(fdh)(3) are thermally stable and can be sublimed, whereas NH4[Ce(fdh)(4)] decomposes during heating. The compounds were characterized by mass spectrometry, infrared spectroscopy and thermal analysis (TG/DTA). The crystal structures of Ce(fdh)(4) and NH4[Ce(fdh)(4)] were determined. NH4[Ce(fdh)(4)] crystallized in the orthorhombic space group Pnna with a = 32.988(11), b = 17.989(9), c = 15.064(5) Angstrom add z = 8. Ce(fdh)(4) crystallized in the monoclinic space group Cc with a = 20.85(3), b = 11.738(12), c = 17.05(5) Angstrom, beta = 95.65(19)degrees and Z = 4.