Solid-state 35/37Cl NMR detection of chlorine atoms directly bound to paramagnetic cobalt(II) ions in powder samples

Abstract

We report high-quality solid-state ^35/37Cl NMR spectra for chlorine atoms directly bonded to paramagnetic cobalt(II) ions (high spin S = 3/2) in powered samples of CoCl₂, CoCl₂·2H₂O, CoCl₂·6H₂O, and CoCl₂(terpy) (terpy = 2,2′:6′,2″-terpyridine). Because solid-state ^35/37Cl NMR spectra for paramagnetic cobalt(II) compounds often cover an extremely wide spectral range, they were recorded in this work in the form of variable-offset cumulative spectra. Solid-state ^35/37Cl NMR measurements were performed at three magnetic fields (11.7, 14.1, and 16.5 T) and analysis of data yielded information about ^35/37Cl quadrupole coupling and hyperfine coupling tensors in these paramagnetic cobalt(II) compounds. Experimental ^35/37Cl NMR tensors were found to be in reasonable agreement with quantum chemical calculations based on a periodic DFT method implemented in BAND.