Solid-state high-resolution NMR studies on spin density distribution of a ferromagnetic coordination polymer: Ni(NCS)2(Him)2

Abstract

We determined hyperfine coupling constants (hfcc) of the imidazole ligand in a ferromagnetic coordination polymer, di-μ-thiocyanatobis(imidazole)nickel(II), using 1H-, 2H-, and 13C-MAS-NMR. Partially or fully deuterated sample was prepared to measure temperature dependence of the isotropic shifts of NMR signals. We obtained hfcc of AC = +0.57, +0.69, +1.88 MHz for 2-, 4-, 5-carbon and AH = +0.66, +0.37, +0.48, +0.53 MHz for 1-, 2-, 4-, 5-proton in the imidazole ligand, respectively, which indicates that unpaired electron in dx2*y2 orbital of Ni(II) ion delocalizes over the imidazole ligand. On the basis of the NMR and DFT results, we proposed an interchain superexchange pathway through N-H...S hydrogen bond.http://www.sciencedirect.com/science/journal/0277538