Molecular and electron-spin structures of a ring-shaped mixed-valence polyoxovanadate (IV, V) studied by B-11 and Na-23 solid-state NMR spectroscopy and DFT calculations

作者：Iijima Takahiro^*; Yamase Toshihiro; Nishimura Katsuyuki

来源：Solid State Nuclear Magnetic Resonance, 2016, 76-77: 15-23.

DOI：10.1016/j.ssnmr.2016.03.004

• POM
• Paramagnetic
• Antiferromagnetic
• Open shell
• Quadrupole
• MQMAS

B-11 and Na-23 solid-state nuclear magnetic resonance (NMR) spectra of ring-shaped paramagnetic crystals of H-15[(V7V5B32O84Na4)-V-IV-B-V] 13H(2)O containing seven d(1) electrons from V-IV were studied. Magic-angle-spinning (MAS) and multiple-quantum MAS NMR experiments were performed at moderate (9.4 T) and ultrahigh magnetic fields (21.6 T). The NMR parameters for quadrupole and isotropic chemical shift interactions were estimated by simulation of the NMR spectra and from relativistic density functional theory (DFT) calculations. Four Na ions incorporated into the framework were found to occupy four distinct sites with different populations. The DFT calculation showed that d(1) electrons with effectively one up-spin caused by strong antiferromagnetic interactions were delocalized over the 12 V ions.

• 出版日期2016-7