The preparation of, and electrochemical studies on, some substituted aryl dithiadiazolylium salts and dithiadiazolyl radicals

Aherne, Christine M.; Banister, Arthur J.; Hibbert, Thomas G.; Luke, Anthony W.; Rawson, Jeremy M.

doi:10.1016/s0277-5387(97)00235-0

Cited by 15 publications

(11 citation statements)

References 20 publications

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“…For example, attempts to correlate dimerisation with small variations in spin density distribution or redox behaviour of the dithiadiazolyl ring ultimately proved unsuccessful. 42,78 Subsequent studies focussed on intermolecular effects. To date, no dithiadiazolyl radicals containing hydrogen bonding groups have been synthesised (although efforts to this end are underway in our group).…”

Section: Discussionmentioning

confidence: 99%

Crystal engineering with dithiadiazolyl radicals

Haynes

2011

CrystEngComm

108

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Section: Discussionmentioning

confidence: 99%

Crystal engineering with dithiadiazolyl radicals

Haynes

2011

CrystEngComm

108

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“…One of the most studied of these families of radicals is the 1,2,3,5-dithiadiazolyl (DTDA) radical which has been explored as a building block in the field of organic radical conductors, exhibiting conductivities up to 10 2 S/cm and as building blocks in the design of some of the highest T C organic magnets, as paramagnetic ligands in coordination chemistry and as photoconducting materials . Electrochemical, EPR, and spin density studies have shown that the singly occupied molecular orbital (SOMO) of the DTDA ring is localized on the S/N ring and to a good approximation the R group (Scheme ) can be modified without change to the electronics of the DTDA ring. Previous work has focused on the ability to tailor the R substituent in order to modify the solid-state packing and the resultant solid-state properties .…”

Section: Introductionmentioning

confidence: 99%

Structural, Magnetic, and Optical Studies of the Polymorphic 9′-Anthracenyl Dithiadiazolyl Radical

et al. 2019

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The fluorescent 9′-anthracenyl-functionalized dithiadiazolyl radical (3) exhibits four structurally determined crystalline phases, all of which are monomeric in the solid-state. Polymorph 3α (monoclinic P21/c, Z' = 2) is isolated when the radical is condensed onto a cold substrate (enthalpically favored polymorph) whereas 3β (orthorhombic P212121, Z' = 3) is collected on a warm substrate (entropically favored polymorph). The α and β polymorphs exhibit chemically distinct structures with 3α exhibiting face-to-face π−π interactions between anthracenyl groups while 3β exhibits edge-to-face π−π interactions. 3α undergoes an irreversible conversion to 3β on warming to 120 o C (393 K). The β-phase undergoes a series of reversible solid-state transformations on cooling; below 300 K a phase transition occurs to form 3γ (monoclinic P21/c, Z' = 1) and on further cooling below 165 K a further transition is observed to 3δ (monoclinic P21/n, Z' = 2). Both 3β  3γ and 3γ  3δ transitions are reversible (single-crystal X-ray diffraction) and the 3γ  3δ process exhibits thermal hysteresis with a clear feature observed by heat capacity measurements. Heating 3β above 160 o C generates a fifth polymorph (3ε) which is distinct from 3α -3δ based on PXRD data. The magnetic behavior of both 3α and the 3β/3γ/3δ system reflect an S = ½ paramagnet with weak antiferromagnetic coupling. The reversible 3δ ↔ 3γ phase transition exhibits thermal hysteresis of 20 K. Below 50 K the value of χmT for 3δ approaches 0 emu•K•mol -1 consistent with formation of a gapped state with an S = 0 ground state configuration. In solution both paramagnetic 3 and diamagnetic [3][GaCl4] exhibit similar absorption and emission profiles reflecting similar absorption and emission mechanisms for paramagnetic and diamagnetic forms. Both emit in the deep-blue region of the visible spectrum (λem ~ 440 nm) upon excitation at 255 nm with quantum yields of 4% (3) and 30% ([3][GaCl4]) affording a switching ratio [ΦF(3 + )/ΦF(3)] of 7.5 in quantum efficiency with oxidation state. Solid-state films of both 3 and [3][GaCl4] exhibit emission bands at longer wavelength (490 nm) attributed to excimer emission.

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“…11 When R is a para-or meta-substituted phenyl group, the range of potentials for both oxidation and reduction fall within a narrow potential window: oxidation potentials of these radicals vary from +0.57 to +0.68 V vs SCE in acetonitrile. 87,94,95 Radicals with electron donating or withdrawing groups directly attached to the ring show a stronger substituent dependence. 96 For example, radical 35 with R = NMe 2 is oxidized at +0.35 V and reduced at −0.96 V, while the derivative with R = CF 3 has oxidation and reduction potentials of +0.91 and −0.42 V respectively.…”

Section: 235-dithiadiazolyl Radicalsmentioning

confidence: 99%

The Synthesis and Characterization of Stable Radicals Containing the Thiazyl (SN) Fragment and Their Use as Building Blocks for Advanced Functional Materials

Hicks

2010

Stable Radicals

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The preparation of, and electrochemical studies on, some substituted aryl dithiadiazolylium salts and dithiadiazolyl radicals

Cited by 15 publications

References 20 publications

Crystal engineering with dithiadiazolyl radicals

Crystal engineering with dithiadiazolyl radicals

Structural, Magnetic, and Optical Studies of the Polymorphic 9′-Anthracenyl Dithiadiazolyl Radical

The Synthesis and Characterization of Stable Radicals Containing the Thiazyl (SN) Fragment and Their Use as Building Blocks for Advanced Functional Materials

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