Synthesis and magnetic properties of (C5H5) (3) Ce-Center-Dot-HMPA
The 1:1 adduct (C3H5)3Ce.O=P(NMe2)3 of cerium (III)-triscyclopentadienide with hexamethylphosphoric triamide (HMPA) was synthesized, isolated, purified and characterized by elemental analysis, IR- and H-NMR spectroscopy. The H-NMR spectrum obtained in solution in CDCI3 at room temperature exhibits a single signal for the Cp-proton at 5.6 ppm and a signal for the CH3 proton of the vase HMPA at 0.49 ppm. The paramagnetic shift due to the Ce(III) ion could be evaluated by comparison to the corresponding signals of the homologous diamagnetic compound Cp3La.HMPA.The temperature dependent paramagnetic susceptibility of the compound was measured within the temperature range from 4.2 up to 300K.From the 1/Xmol vs T-plot the empirical constant C=0.78 m3 K mol-1 was evaluated with a Curie-Weiss constant o of -71 K. The temperature dependence of the magnetic moment is consistent with a Ce(III) ion. The ground state of the Ce ion is only partially populated. The magnetic moment at room temperature is 2.25 an indication of covalency, as it has been observed for several Ce(III) organometallics.
Bibliographic Reference: Article: Journal of Alloys and Compounds 277 (1998) 798-800
Record Number: 199910475 / Last updated on: 1999-03-19
Original language: en
Available languages: en