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Alkyl and aryl derivatives of tricyclopentadienyl cerium(IV) and bisindenyl cerium(IV)

1973; Pergamon Press; Volume: 35; Issue: 1 Linguagem: Inglês

10.1016/0022-1902(73)80646-3

1878-1225

B. L. Kalsotra, R. K. MULTANI, B.D. Jain,

Lanthanide and Transition Metal Complexes

The cerium(III) β-diketonate compounds [Ce2(β-diket)6(tetraglyme)] [β-diket = etbd (1-ethoxy-4,4,4-trifluorobutane-1,3-dionate)1, hfpd (1,1,1,5,5,5-hexafluoropentane-2,5-dionate) 2 and hfod (1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionate) 3 and tetragrlyme = CH3O(CH2CH2O)4CH3] were sytnhesised from the reaction of CeCl3 · 7H2O and tetraglyme with an aqueous ethanolic solution of Na(β-diket). The unusual reaction of cerium ammonium nitrate, [Ce(NH4)2(NO3)6], and Hetbd in an ammoniacal mixture of dimethoxyethane resulted in the ammonium cerium(III) salt, [NH4][Ce(etbd)4] 4, rather than the expected cerium(IV) species. All compounds were characterised by spectroscopic methods and in the cases of 1 and 4, also by X-ray crystallography. The structure of [Ce2(etbd)6(tetraglyme)] 1 consists of two Ce(etbd)3 moieties bridged by a tetraglyme molecule. The two Ce atoms in this molecule are eight and nine coordinate respectively with distorted docahedral and monocapped square antiprismatic geometries. The crystal structure of 4 is stabilised by an extensive hydrogen bonding network involving the NH4+ cation and one oxygen atom from each of the four etbd ligands belonging to the [Ce(etbd)4]− anion, with additional NH4+…F3C(etbd) interactions. The Ce atom in the [Ce(etbd)4]− anion is eight coordinate with a distorted square antisprismatic geometry. All the complexes are air and moisture stable, and some compounds have good volatilities and thermal stabilities, as demonstrated by sublimation and TGA/DSC studies.