Preparation and characterization of the disjoint diradical 4,4`-bis(1, 2,3,5-dithiadiazolyl) [S{sub 2}N{sub 2}C-CN{sub 2}S{sub 2}][I] and its iodine charge transfer salt [S{sub 2}N{sub 2}C-CN{sub 2}S{sub 2}][I]

Journal Article · Wed Jan 17 00:00:00 EST 1996 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja952144x· OSTI ID:199419

Bryan, C D; Cordes, A W ^[1]; Goddard, J D; others, and ^[2]

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1. Univ. of Arkansas, Fayetteville, AK (United States)
2. Univ. of Guelph (Canada)

Condensation of oxamidrazone with sulfur dichloride in acetonitrile affords 4,4`-bis-(1,2,3,5-dithiadiazolium) dichloride in moderate yield. Reduction of this salt with triphenylantimony yields the diradical 4,4`-bis(1,2,3,5-dithiadiazolyl) [S{sub 2}N{sub 2}C-CN{sub 2} S{sub 2}], which has been isolated and characterized in the solid state as its dimer [S{sub 2}N{sub 2}C-CN{sub 2}S{sub 2}]{sub 2}. The diradical is disjoint, and ab initio molecular orbital methods confirm a very small energy gap (< 0.5 Kcal/mol) between the triplet and diradical singlet states, regardless of the torsion angle about the central C-C bond. In accord with these theoretical predictions the ESR spectrum of the diradical consists (in CHCl{sub 3} at 273 K) of a simple five-line pattern (a{sub N} = 0.50 mT, g = 2.011), i.e., there is no observable exchange coupling between the two centers. In the solid state, the dimer [S{sub 2}N{sub 2}C-CN{sub 2}S{sub 2}]{sub 2} forms a slipped stack structure, with a mean intradimer S-S distance of 3.078 A and mean interdimer S---S contact of 3.761 A. Cosublimation of the diradical with iodine produces the charge-transfer salt [S{sub 2}N{sub 2}C-CN{sub 2}S{sub 2}][I], orthorhombic space group Ccmm, a = 11.909(3) A, b = 3.271(2) A, c = 19.860(6) A, Z = 4 at (293 K). In this structure the heterocyclic rings form perfectly superimposed and evenly spaced stacks along the y direction, with channels of disordered iodines. 47 refs., 8 figs., 4 tabs.

• OSTI ID: 199419
• Journal Information: Journal of the American Chemical Society, Vol. 118, Issue 2; Other Information: PBD: 17 Jan 1996
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
ORGANIC SULFUR COMPOUNDS
CHEMICAL PREPARATION
ELECTRIC CONDUCTIVITY
ORGANIC NITROGEN COMPOUNDS
IODINE COMPLEXES
PHASE TRANSFORMATIONS
TEMPERATURE DEPENDENCE
RADICALS
MOLECULAR ORBITAL METHOD
ELECTRONIC STRUCTURE
DIMERS
MOLECULAR STRUCTURE
MAGNETIC SUSCEPTIBILITY
BOND LENGTHS
ELECTRON SPECTRA