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