MAGNETIC AND STRUCTURAL PROPERTIES OF THE OPEN FRAMEWORK [Nd2(CO2(CH2)CO2)(H2O)6]·2H2O

C. G. POZZI; G. ECHEVERRÍA; G. PUNTE; E. V. BRUSAU; G. E. NARDA; J. A. ELLENA; R. FACCIO; L. SUESCUN; A. W. MOMBRÚ

Orlando, USA

Congreso; American Crystallographic Association (ACA), Annual Meeting; 2005

AC susceptibility measurements performed on polycrystalline samples of the title compound in the temperature range 14 - 320K showed a magnetic transition at TC = 280(2)K, evidenced by a change in the slope of c´T vs. T. To investigate a possible structural contribution to this transition, single crystal x-ray analyses in the range 270 - 290K were carried out each 2K. In agreement with data already reported in the literature [2] and studies performed at 120 and 296K, the structure is orthorhombic, space group Pbcn, and contains one Nd per asymmetric unit. Nd(III) cations are linked into sheets by carboxylates through two distinct binding modes. Small discontinuities, such as that in cell volume expansion with temperature manifest the existence of changes in the structural properties accompanying the magnetic behaviour. Modifications in the superexchange paths connecting Nd(III) cations and variations in the hydrogen bond network linking waters are discussed as possible causes of the observed magnetic transition.