title: Bistability and the phase transition in 1,3,2-dithiazolo[4,5-b]pyrazin-2-yl.
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.
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
authors.forename: Jaclyn L
authors.initials: JL
authors.lastname: Brusso
authors.forename: Owen P
authors.initials: OP
authors.lastname: Clements
authors.forename: Robert C
authors.initials: RC
authors.lastname: Haddon
authors.forename: Mikhail E
authors.initials: ME
authors.lastname: Itkis
authors.forename: Alicea A
authors.initials: AA
authors.lastname: Leitch
authors.forename: Richard T
authors.initials: RT
authors.lastname: Oakley
authors.forename: Robert W
authors.initials: RW
authors.lastname: Reed
authors.forename: John F
authors.initials: JF
authors.lastname: Richardson