Coordination Networks from [Te4]2+ Clusters and Polynitriles

Abstract

The reactions of a series of organic polynitriles with [Te4][AsF6]2 in liquid SO2 solution lead either to reduction of [Te4]2+ to elemental tellurium or to the formation of coordination polymers. With 1,3‐dicyanobenzene (1,3‐DCB), 1,4‐dicyanobenzene (1,4‐DCB), 1,2,4,5‐tetracyanobenzene (TCB), tetracyanoethylene (TCNE) and tetracyanochinodimethane (TCNQ) the coordination complexes [Te4][AsF6]2 · 2(1,3‐DCB), [Te4][AsF6]2 · 3(1,4‐DCB) · 2SO2, [Te4][AsF6]2 · TCB, [Te4][AsF6]2 · TCNE and [Te4][AsF6]2 · TCNQ · 8SO2 were isolated and characterized by crystal structure analyses and vibrational Raman spectroscopy. The nitriles are coordinated to the square‐planar clusters forming 1D chains, 2D arrangements and 3D networks. Tetrakis(dicyanomethylene)‐cyclobutendiide [C4(C{CN}2)4]2‒ is oxidized by [Te4]2+ to the neutral cyanocarbon C4(C{CN}2)4 structurally representing a 4[radialene]. The ionization potentials and electron affinities of the cyanamide anion, cyanogen, 1,2‐DCB, 1,3‐DCB, 1,4‐DCB, TCB, C4(C{CN}2)4, TCNE and TCNQ and those polynitriles, which cause reduction of [Te4]2+, were calculated at coupled‐cluster level of theory in order to examine possible reasons for the stability of the coordination polymers based on electronic properties of the nitriles.