Synthesis, structure, and 13C and 31P CP/MAS NMR of crystalline modifications of the polynuclear thallium(I) O,O′-dicyclohexyl phosphorodithioate complex [Tl{S2P(O-cyclo-C6H11)2}] n

Abstract

Two crystalline modifications (Ia and Ib) of the polynuclear thallium (I) O,O′-dicyclohexyl phosphorodithioate complex [Tl{S2P(O-cyclo-C6H11)2}]n have been synthesized and characterized by CP/MAS NMR (13C, 31P). From full 31P CP/MAS NMR spectra, the χ2 plots were constructed to calculate the 31P chemical shift anisotropy 31P − δaniso = (δzz − δiso) and asymmetry parameters η = (δyy − δxx)/(δzz − δiso). The data obtained for the O,O′-dicyclohexyl phosphorodithioate (Dtph) groups (in both modifications) are evidence that the 31P chemical shift tensors are intermediate between rhombic and axially symmetric. However, whereas the rhombic component dominates for Ia, the tensor for Ib is close to axially symmetric (for δzz < δyy ≈ δxx). The same pattern of the MAS spectra corresponding to negative δaniso (δzz < δyy < δxx) points to a bridging or terminal/bridging coordination mode of the Dtph groups. X-ray crystallography shows that complex Ib has a polynuclear structure (of the chain polymer type). The chains are composed of alternating structurally nonequivalent noncentrosymmetric binuclear molecules [Tl2{S2P(O-cyclo-C6H11)2}2]. All Dtph ligands have the terminal/μ3-bridging coordination mode.