title: Studies on a "Disappearing Polymorph": Thermal and Magnetic Characterization of α-p-NCC6F4CNSSN•.
abstract: The α-and β-phases of the thiazyl radical p-NCC6F4CNSSN•(1) can be selectively prepared by careful control of the sublimation conditions, with the α-phase crystallizing preferentially when the substrate temperature is maintained below -10 °C, whereas the β-phase is isolated when the substrate temperature is maintained at or above ambient temperature. Differential scanning calorimatry studies reveal that the α-phase converts to the β-phase upon warming over the range 111-117 °C (ΔH = +4 kJ·mol-1) via a melt-recrystallization process, with the β-phase itself melting at 167-170 °C (ΔHfus= 27 kJ·mol-1). IR and Raman spectroscopy can be used to clearly discriminate between 1α and 1β. The α-phase shows a broad maximum in the magnetic susceptibility around 8 K that, coupled with a broad maximum in the heat capacity, is indicative of short-range order. Some field dependence of the susceptibility below 3 K is observed, but the lack of features in the ac susceptibility, M vs H plots, or heat capacity mitigates against long-range order in 1α.
authors.affiliation: Department of Chemistry & Biochemistry, University of Windsor , 401 Sunset Avenue, Windsor, OntarioN9B 3P4, Canada.
authors.forename: Yassine
authors.initials: Y
authors.lastname: Beldjoudi
authors.affiliation: Departamento de Física de la Materia Condensada, Facultad de Ciencias, and Instituto de Ciencia de Materiales de Aragon, CSIC-Universidad de Zaragoza , E-50009 Zaragoza, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Arauzo
authors.affiliation: Departamento de Física de la Materia Condensada, Facultad de Ciencias, and Instituto de Ciencia de Materiales de Aragon, CSIC-Universidad de Zaragoza , E-50009 Zaragoza, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Palacio
authors.affiliation: Department of Chemistry, Brock University , 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada.
authors.forename: Melanie
authors.initials: M
authors.lastname: Pilkington
authors.affiliation: Department of Chemistry & Biochemistry, University of Windsor , 401 Sunset Avenue, Windsor, OntarioN9B 3P4, Canada.
authors.forename: Jeremy M
authors.identifier: 0000-0003-0480-5386
authors.initials: JM
authors.lastname: Rawson