Paramagnetic Properties and Moderately RapidConformational Dynamics in the Cobalt(II) Calix[4]arene Complex by NMR |
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| Authors: | Eugeny Nikolaevich Zapolotsky Sergey Pavlovich Babailov Gennadiy Alexandrovich Kostin |
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| Affiliation: | Nikolayev Institute of Inorganic Chemistry SB RAS, 630090 Novosibirsk, Russia; (S.P.B.); (G.A.K.) |
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| Abstract: | ![]()
1H NMR measurements are reported for the CD2Cl2/CDCl3 solutions of the Co(II) calix[4]arenetetraphosphineoxide complex (I). Temperature dependences of the 1H NMR spectra of I 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 pinched cone ↔pinched cone interconversion of I (with activation Gibbs energy ΔG≠(298K) = 40 ± 3 kJ/mol. Due to substantial temperature dependence of paramagnetic shifts, complex I can be used as model compound for designing an NMR thermosensor reagent for local temperature monitoring. |
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| Keywords: | complexes of lanthanides calix[4]arene tetraphosphineoxide substituent molecular dynamics Gibbs free energy of activation dynamic NMR |
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