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A Co-59 Nuclear Magnetic Resonance Study of the Interaction of Lanthanoid Shift Reagents with Tris(β-diketonato)cobalt(III) Complexes

1982; Oxford University Press; Volume: 55; Issue: 6 Linguagem: Inglês

10.1246/bcsj.55.1798

1348-0634

Masatoshi Hirayama, Yoshimichi Kawamata, Yuki Fujii, Yoshiharu Nakano,

Radioactive element chemistry and processing

Abstract Ln(fod)3 (Ln=La, Pr, Nd, Sm, and Eu)-induced 59Co shifts (δCo) for a series of tris(β-diketonato)Co(III) complexes were determined directly from separate observations of the free complexes and 1 : 1 adducts with Ln(fod)3 at room temperature (25 °C) in CHCl3; Ln(dpm)3-induced shifts were also observed in CCl4. Values of δCo corrected for the adduct-formation shifts (δ′Co) are separated into contact and pseudo-contact contributions by using the intercept and slope in a linear plot of δ′Co⁄<Sz> vs. D⁄<Sz>. It is suggested from the estimated hfs constant of 59Co (≈−0.2 G, 10−4T) that the spin polarization mechanism may be predominant for the electron spin transfer from Ln ion into Co ion.