Secondary bonding in para-substituted diphenyltellurium dichlorides (p-XC6H4)2TeCl2 (X = H, Me, MeO) probed by 125Te MAS NMR spectroscopy.: Crystal and molecular structure of (p-MeC6H4)2TeCl2

The solid-state structures of the previously known para-substituted diphenyltellurium dichlorides, (p-XC6H4)(2)TeCl2 (X = H (1), Me (2), MeO (3)) were investigated by Te-125 MAS NMR spectroscopy and in case of 2 by single crystal X-ray diffraction. The Te-125-NMR shielding anisotropy (SA) was studied by tensor analyses based on relative intensities of the observed spinning sidebands. Solid-state NMR parameters, namely the isotropic chemical shift (delta(iso)), anisotropy (xi) and asymmetry (eta), were discussed in relation to the molecular structures established by X-ray crystallography. The asymmetry (eta) was found to be particularly sensitive to structural differences stemming mostly from the diverse secondary Te...Cl interactions, but no correlation with geometric parameters could be established. (C) 2003 Elsevier Science B.V. All rights reserved.