A Magnetically Robust Triplet Ground State Sulfur-Hydrocarbon Diradical Dication

Abstract

The one- and two-electron oxidation reactions of tetrathiolated di-<i>tert</i>-butylpyrene compound <b>1</b> with NO[Al(OR_F)₄] (OR_F = OC(CF₃)₃) resulted in radical cation salt <b>1</b>^•+[Al(OR_F)₄]^- and diradical dication salt <b>1</b>^2+••<b>·</b>2[Al(OR_F)₄]^-, respectively. Both salts were isolated as stable crystals and investigated by single-crystal X-ray diffraction, EPR spectroscopy, SQUID measurements, and UV-vis spectroscopy. The electron spin density is delocalized on one single sulfur-doped ring in <b>1</b>^•+ and on both sulfur-doped rings in <b>1</b>^2+••. The diradical dication <b>1</b>^2+•• features a robust triplet ground state, representing the first example of a high-spin sulfur-hydrocarbon diradical.