The first solid state paramagnetic 1,2,3,5-dithiadiazolyl radical; X-ray crystal structure of [p-NCC6F4CNSSN]?

Banister, Arthur J.; Bricklebank, Neil; Clegg, William; Elsegood, Mark R. J.; Gregory, Christopher I.; Lavender, Ian; Rawson, Jeremy M.; Tanner, B. K.

doi:10.1039/c39950000679

Cited by 81 publications

(62 citation statements)

References 8 publications

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“…This compound is polymorph. The a-phase of 1 orders as an antiferromagnet at 8 K [9]. This high temperature indicates that the magnetic interactions are much stronger than in previously reported open-shell N-and O-based radicals.…”

Section: Introductionmentioning

confidence: 63%

A CW-EPR and ESEEM spectroscopic study of the dithiadiazolyl radicals p-XC6F4CNSSN (X = CN, Br)

et al. 2001

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Two dithiadiazolyl radicals, p-NCC6F4CNSSN and p-BrC 6 F4CNSSN, have recently been found to be paramagnetic in the solid state. While the (3-phase of the first one exhibits spontaneous magnetization below 36 K, the second one shows a paramagnetic character in the solid state. The spin density distribution in these radicals is examined through continuous-wave electron paramagnetic resonance and electron spin echo envelope modulation spectroscopies. Hyperfine correlation sublevel spectroscopy provides information about the interaction of the unpaired spin with F and N nuclei. A signal coming from the interaction with Br nucleus is also detected. The superhyperfine coupling constants of the unpaired electron with the magnetic nuclei are obtained and values of the corresponding spin densities, f and f -f, can be estimated in the isolated radicals. Spin density distribution has also been calculated in both molecules with density functional theory, being in excellent agreement with those determined from the spectra. The spin density is mainly concentrated in the dithiadiazolyl ring, but some spin density is observed on the fluorinated aromatic rings. They also provide a strong basis to understand the differences of the magnetic behavior of both molecules in terms of their respective packing in the solid state.

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Section: Introductionmentioning

confidence: 63%

A CW-EPR and ESEEM spectroscopic study of the dithiadiazolyl radicals p-XC6F4CNSSN (X = CN, Br)

et al. 2001

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“…[127,128] It also provides another example of concomitant crystallization by sublimation. Large black blocks of the a phase may be obtained pure by very rapid vacuum sublimation at 120 8C and 10 À2 Torr.…”

Section: Free Radicals By Sublimationmentioning

confidence: 97%

Concomitant Polymorphs

Bernstein

Davey

Henck

1999

Angewandte Chemie Intl Edit

812

671

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The simultaneous appearance of polymorphs of a substance has long been recognized but rarely noted or systematically studied. This phenomenon can be useful in the investigation of solid materials and in understanding the relative crystal energetics of polymorphic materials. This review covers the thermodynamic and kinetic factors that govern competitive and concomitant polymorphic crystallization. One of the many examples surveyed is a cyanine/oxonol complex, for which different relative molecular orientations in two of the many reported polymorphs are shown.

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“…, 1, which is polymorphic [9,10]. The a-phase orders antiferromagnetically at 8 K [9], whereas preliminary magnetic measurements of the b-phase, 1b, indicate the onset of a spontaneous magnetic moment below 36 K [10], an exceptionally high temperature for a purely organic free radical.…”

mentioning

confidence: 99%

High-Temperature Magnetic Ordering in a New Organic Magnet

et al. 1997

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The first solid state paramagnetic 1,2,3,5-dithiadiazolyl radical; X-ray crystal structure of [p-NCC6F4CNSSN]?

Abstract: The solid state structure of the fluorinated If2,3,. is reported; it is the first dithiadiazolyl radical t o retain its paramagnetic character in the solid state.

Cited by 81 publications

References 8 publications

A CW-EPR and ESEEM spectroscopic study of the dithiadiazolyl radicals p-XC6F4CNSSN (X = CN, Br)

A CW-EPR and ESEEM spectroscopic study of the dithiadiazolyl radicals p-XC6F4CNSSN (X = CN, Br)

Concomitant Polymorphs

High-Temperature Magnetic Ordering in a New Organic Magnet

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