The Electronic and Magnetic Properties of SSSNCCNSSS(M)₂ (M = AsF₆⁻,SbF₆, Sb₂F₁₁⁻) and Evidence for the Isostructural Monocation Monoradical (CNSSS)⁺⁻

Abstract

The variable temperature magnetic behaviour of the AsF₆ ⁻, Sb₂F₁ ⁻ and presently reported SbF₆ ⁻ salts of Bis(l,2,3,4-trithiazolium), ^z.rad;+SSSNCCNSSS⁺⁻, are complex but indicate intermolecular antiferromagnetic interactions and temperature independent paramagnetism, as well as intramolecular antiferromagnetic coupling leading to a singlet ground state with a nearly degenerate, thermally accessible triplet excited state. ESR spectroscopy confirms the triplet state and also shows a narrow resonance with a similar isotropic g value; possibly due to the presence of a diradical isomer of 1²⁺ · 1²⁺ is readily reduced to the monocation monoradical. Vibrational spectroscopy suggests that 1⁺ has a similar geometry to 1²⁺ with some weakening of the bonds within the rings. ESR spectroscopy shows a pentet at −80°C, indicating that the unpaired electron couples with two equivalent N atoms, consistent with the electron delocalized over both rings.

Keywords::

• trithiazolium
• triplet
• radical
• ESR
• Bleany-Bowers
• antiferromagnetism
• temperature independant paramagnetism (TIP)