Redox, Magnetic, and Structural Properties of 1,3,2-Dithiazolyl Radicals. A Case Study on the Ternary Heterocycle S3N5C4
Citations Over TimeTop 10% of 1998 papers
Abstract
The characterization of the heterocyclic radical 1,2,5-thiadiazolo[3,4-b]-1,3,2-dithiazolo[3,4-b]pyrazin-2-yl (TDP-DTA) is described. The compound is prepared by treatment of 5,6-dithiolo-1,2,5-thiadiazolo[3,4-b]pyrazine with S3N3Cl3 and purified by fractional sublimation in vacuo. The results of cyclic voltammetry and ESR analysis of TDP-DTA and related heterocyclic dithiazolyls indicate that the spin distributions and donor/acceptor properties of these radicals are extremely sensitive to the nature of the 4,5-substituents. The crystal structure of TDP-DTA has been determined at two temperatures. At 293 K, the crystals are triclinic, space group P1̄, with a = 4.4456(8), b = 8.407(2), c = 9.671(3) Å, α = 71.34(2), β = 89.28(2), γ = 87.80(2)°, Z = 2 (for C4N5S3); at 150 K the crystals are triclinic, space group P1̄, with a = 7.489(7), b = 9.593(4), c = 10.759(6) Å, α = 65.77(4), β = 74.10(6), γ = 74.64(6)°, Z = 2 (for C8N10S6). At 293 K the structure consists of ribbons of TDP-DTA radicals packed in a slipped π-stack arrangement. In the low temperature phase alternate layers of ribbons are shifted laterally to produce arrays of dimers. Within these dimers three long (3.401(5), 3.460(5) and 3.511(5) Å) interannular S---S contacts link the two molecules. A multiple “tectonic plate” slippage mechanism is proposed to account for the interconversion of the two phases. The structural results are discussed in the light of variable temperature magnetic susceptibility measurements.
Related Papers
- → Comparison of the vibrational spectra of K2Cr2O7, Rb2Cr2O7 and CS2Cr2O7(1973)9 cited
- → An x-ray study of some simple derivatives of ethane.—Part I(1928)19 cited
- → Triclinic polymorph of 4-[4-(4-formylphenoxy)butoxy]benzaldehyde(2012)3 cited
- → The structure of a triclinic form of octafluoroselenanthrene, (C6F4)2Se2(1986)5 cited
- → Exhaustive indexing of triclinic powder diffraction patterns with known unit cell parameters(1994)1 cited