The Chemistry of Dithiadiazolylium and Dithiadiazolyl Rings**Dedicated to Dr. Z. V. Hauptman, in appreciation of his important contribution to sulfur-nitrogen and carbon-sulfur-nitrogen chemistry.

Rawson, Jeremy M.; Banister, Arthur J.; Lavender, Ian

doi:10.1016/s0065-2725(08)60422-5

Cited by 148 publications

(36 citation statements)

References 128 publications

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“…1). 64,65 This interaction stabilizes the singlet ground state which is experimentally supported by χT values ~ 0 emu.K.mol -1 at low temperature. [26][27][28][29] Passmore was the first to indicate that the "closed-shell" dimerization of DTDA radicals inadequately described the electronic ground state of these materials and that they had some diradical character, 23 more recently studied computationally by Kertesz.…”

Section: Discussionmentioning

confidence: 67%

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

Constantinides

Carter

Eisler

et al. 2017

Crystal Growth & Design

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ABSTRACT:The syntheses and characterization of the aryl-substituted dithiadiazolyls, 2 -Cl-5 -X-C 6 H 3 CNSSN • [1 (X = F), 2 (X = Cl), 3 (X = Br), 4 (X = I)] are described. In all four cases the radicals adopt distorted stacks of π*-π* dimers with inter-stack S···X contacts. In 1 (monoclinic P2/c) S···Cl contacts are manifested through a non-crystallographic 3-fold axis forming supramolecular trimers whereas the inter-stack S…X contacts in 2 (triclinic P-1), 3 and 4 (which form an isostructural pair, orthorhombic Pna2 1 ) form supramolecular chains. While all the structures adopt π*-π* cis-oid dimer motifs, tuning the halogen modifies the intra-dimer S···S distance. Variable temperature SQUID magnetometry and X-band CW-EPR studies revealed the presence of a thermally accessible triplet state in all cases, with the singlet-triplet separation appearing in the order 1 > 2 > 3 > 4, consistent with a reduction in the overlap integral with increasing intra-dimer S···S separation. Variable temperature structural studies on both 2 and 4 reveal a structural evolution from a distorted π-stack motif towards a regular π-stacked array on warming. This is particularly pronounced in 2 where the intermolecular S…S separations along the stacking direction converge on a regular 3.6 Å spacing at ambient temperature.3

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Section: Discussionmentioning

confidence: 67%

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

Constantinides

Carter

Eisler

et al. 2017

Crystal Growth & Design

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“…Many of these radicals have been isolated in the solid state. Whilst the majority form diamagnetic closed-shell dimers via a π*-π* dimerisation process, [ 4 ] a small number of perfluorophenyl derivatives 1-3 have recently been found which retain their paramagnetism in the solid state [5,6,7]. Radical 1 is polymorphic; the α-phase exhibits a maximum in χ around 8 K indicative of antiferromagnetic ordering, [5a] whilst the β-phase undergoes a phase transition to a canted antiferromagnetic phase at 36 K [5b].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

et al. 2004

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Abstract:The dithiadiazolyl radical p-NCC 6 F 4 C 6 F 4 CNSSN• (4) retains its monomeric nature in the solid state with molecules linked together into chains via supramolecular CN···S interactions. Variable temperature magnetic studies on 4 show that it behaves as a near-ideal Curie paramagnet (|θ| less than 0.1 K), indicating negligible intermolecular exchange. The effective magnetic moment (1.78 µ B ) is temperature independent and in excellent agreement with the value expected for an S = ½ paramagnet with g = 2.01 (1.74µ B ). The lack of exchange coupling between radicals is attributed to the absence of significant orbital overlap between radical centres.

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“…The heterocyclic bond distances and angles are in good agreement with those reported for other dithiadiazolyl radical structures. 2 The C u N bond at 1.3308͑6͒ Å is intermediate between values expected for C u N single and C v N double bonds ͑1.47 and 1.27 Å, respectively͒. 33 However, there is a contraction of the unit-cell volume by 2.5% on cooling from 220 to 20 K ͑Table VI͒.…”

Section: A Structural Studiesmentioning

confidence: 95%

“…2 This has subsequently led to a number of other heavy p-block organic radicals with high magnetic ordering temperatures. [3][4][5] Among these radicals the family of dithiadiazolyl radicals has attracted particular attention.…”

Section: Introductionmentioning

confidence: 99%

“…2 In particular, p-NCC 6 F 4 CNSSN has been studied extensively since one of its two solid-state forms undergoes a phase transition to a canted antiferromagnetic state below 36 K, 6 the highest reported temperature for a metal-free compound. Moreover, contrary to most organic magnets whose ordering temperature decreases as an external pressure is applied, the ordering temperature in this compound rises up to 72 K under an hydrostatic pressure of 19 kbar.…”

Section: Introductionmentioning

confidence: 99%

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Spin density studies onp-O2NC6F4CNSSN: A heavyp
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A complete picture of the spin density distribution in the organic radical p-O 2 NC 6 F 4 CNSSN has been obtained by a combination of polarized neutron diffraction, electron paramagnetic resonance ͑EPR͒, and electron-nuclear double resonance ͑ENDOR͒ spectroscopies, and ab initio density-functional theory ͑DFT͒ calculations. Polarized neutron diffraction revealed that the spin distribution is predominantly localized on the N and S atoms ͑+0.25 B and +0.28 B , respectively͒ of the heterocyclic ring with a small negative spin density on the heterocyclic C atom ͑−0.06 B ͒. These spin populations are in excellent agreement with both ab initio DFT calculations ͑spin populations on the C, N, and S sites of −0.07, 0.22 and 0.31, respectively͒ and cw-EPR studies which estimated the spin population on the N site as 0.24. The DFT calculated spin density revealed less than 1% spin delocalization onto the perfluoroaryl ring, several orders of magnitude lower than the density on the heterocyclic ring. cw-ENDOR studies at both X-band ͑9 GHz͒ and Q-band ͑34 GHz͒ frequencies probed the spin populations on the two chemically distinct F atoms. These spin populations on the F atoms ortho and meta to the dithiadiazolyl ring are of magnitude 10 −3 and 10 −4 , respectively.

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The Chemistry of Dithiadiazolylium and Dithiadiazolyl Rings**Dedicated to Dr. Z. V. Hauptman, in appreciation of his important contribution to sulfur-nitrogen and carbon-sulfur-nitrogen chemistry.

Cited by 148 publications

References 128 publications

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

Spin density studies onp-O2NC6F4CNSSN: A heavyp
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et al. 2010
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The Chemistry of Dithiadiazolylium and Dithiadiazolyl Rings**Dedicated to Dr. Z. V. Hauptman, in appreciation of his important contribution to sulfur-nitrogen and carbon-sulfur-nitrogen chemistry.

Cited by 148 publications

References 128 publications

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

Effects of Halo-Substitution on 2′-Chloro-5′-halo-phenyl-1,2,3,5-dithiadiazolyl Radicals: A Crystallographic, Magnetic, and Electron Paramagnetic Resonance Case Study

Synthesis and Magnetic Properties of the Novel Dithiadiazolyl Radical, p-NCC6F4C6F4CNSSN

Spin density studies onp-O2NC6F4CNSSN: A heavypLuzón1, Campo2, Palácio3 et al. 2010Phys. Rev. B18090View full textAdd to dashboardCite

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Spin density studies onp-O2NC6F4CNSSN: A heavyp
Luzón
¹
,
Campo
²
,
Palácio
³

et al. 2010
Phys. Rev. B
18
0
9
0
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