Anisotropic Nuclear Spin Interactions in K2Hg( CN)4: A Multinuclear Solid-state NMR Study

Several anisotropic nuclear spin interactions in solid potassium tetracyanomercurate(II), K2Hg(CN)4, have been characterized using 13C, ISN, and Ig9Hg N M R spectroscopy at 4.70 and 9.40 T. The carbon chemical shielding tensor is axially symmetric, with anisotropy, Au = ull 61 = 329 f 2 ppm. From the 13C and Ig9Hg N M R spectra obtained with magic-angle spinning (MAS), 1J(199Hg,13C)i, = 1540 f 2 Hz; analysisof the Ig9Hg N M R spectra of a static powder sample indicates that this indirect spin-spin interaction is anisotropic, A1J(Ig9Hg,13C) = 950 f 60 Hz. The first report of 2J(199Hg,14/15N) in the solid state is obtained from an analysis of Ig9Hg MAS N M R spectra: 12J(1g9Hg,14N)J = 20.6 f 2.0 H z and IZJ(199Hg,1SN)d = 29.0 f 2.0 Hz. The effective dipolar coupling between Ig9Hg and 14N nuclei, R,tf = 20.0 Hz, is found to be significantly smaller than the direct dipolar interaction, RDD = 43.0 Hz. This reduction is attributed to anisotropy in the indirect spin-spin coupling; A2J(lg9Hg,14N) = 69 f 15 Hz. Analysis of lSN N M R spectra obtained with slow MAS indicates that the nitrogen chemical shift tensor is axially symmetric, with an anisotropy of 477 f 5 ppm.