Bistability and the phase transition in 1,3,2-dithiazolo[4,5-b]pyrazin-2-yl

Jaclyn L Brusso; Owen P Clements; Robert C Haddon; Mikhail E Itkis; Alicea A Leitch; Richard T Oakley; Robert W Reed; John F Richardson

doi:10.1021/ja044979q

Bistability and the phase transition in 1,3,2-dithiazolo[4,5-b]pyrazin-2-yl

J Am Chem Soc. 2004 Nov 17;126(45):14692-3. doi: 10.1021/ja044979q.

Authors

Jaclyn L Brusso¹, Owen P Clements, Robert C Haddon, Mikhail E Itkis, Alicea A Leitch, Richard T Oakley, Robert W Reed, John F Richardson

Affiliation

¹ Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

PMID: 15535673
DOI: 10.1021/ja044979q

Abstract

The molecular radical 1,3,2-dithiazolo[4,5-b]pyrazin-2-yl (PDTA) exhibits magnetic bistability just above room temperature, undergoing a well-defined hysteretic phase change with TC downward arrow = 297(1) K and TC upward arrow = 343(1) K. The crystal structures of the two phases of PDTA have been determined by single-crystal X-ray diffraction at 323(2) K. LT-PDTA consists of diamagnetic (S = 0) nearly superimposed pi-dimer stacks, while that of HT-PDTA comprises slipped stacks of pi-radicals (S = 1/2). The structural interconversion is suggested to proceed via the cooperative breaking and making of intermolecular S- - -N interactions and an inversion symmetry-preserving "domino cascade" of the pi-stacked rings.