Paramagnetic Properties and Moderately RapidConformational Dynamics in the Cobalt(II) Calix[4]arene Complex by NMR.

H NMR measurements are reported for the CDCl/CDCl solutions of the Co(II) calix[4]arenetetraphosphineoxide complex (). Temperature dependences of the H NMR spectra of have been analyzed using the line shape analysis, taking into account the temperature variation of paramagnetic chemical shifts, within the frame of the dynamic NMR method. Conformational dynamics of the 2:1 Co(II) calix[4]arene complexes was conditioned by the ↔ interconversion of (with activation Gibbs energy Δ(298K) = 40 ± 3 kJ/mol.