Higashi, Lois S. published the artcileEmpirical relations between disulfide bond lengths, (nitrogen or carbon)-carbon-sulfur-sulfur torsion angles, and substituents in aromatic disulfides. Crystal and molecular structure of 3,3′-dihydroxydi-2-pyridyl disulfide, Name: Formamidine disulfide dihydrochloride, the publication is Journal of the American Chemical Society (1978), 100(26), 8101-6, database is CAplus.
In the 21 reported crystal structures of sym. disulfides whose sulfur atoms are bound to sp2 carbon atoms, an empirical relationship is found between the S-S bond length and the X-C-S-S (X = C or N) torsion angle. The C-S-S-C torsion angles are generally within about 20° of 90° in those mols. In addition, it is noted that the less frequently encountered X-C-S-S angles near 90° occur only when one strongly electron-donating substituent is present in a position β to the disulfide group in each of the R groups of the RSSR mol., or when both β positions on each R group are substituted, independent of electron negativity. A relatively neutral or electron-withdrawing group in only one β position of each R group (or any substituents at any more distant positions) allows the X-C-S-S torsion angles to be near 0°, and the S-S bond, therefore, to be short. This result is supported by the crystal and mol. structure of 3,3′-dihydroxydi-2-pyridyl disulfide, which has been determined by single-crystal x-ray diffraction techniques using counter methods, and has been refined by full-matrix least-squares procedures to a final conventional R index of 0.035. The yellow monoclinic crystals form in the space group P21/c with a = 7.165 (1) Å,b = 7.656(1) Å,c = 19.517(3) Å,β = 96.77(1)°, and four mols. per unit cell. The average N-C-S-S torsion angle (9°) indicates that the S-S bond (2.0180(7) Å) is nearly in the plane of each pyridine ring. The C-S-S-C torsion angle is 93.2°, and the average S-C bond length is 1.782 Å. The empirical rules presented also successfully describe the 11 transition metal ion complexes involving these disulfides whose structures are known. The C-S-S-C torsion angle has a role in governing the S-S bond length, but is important only when X-C-S-S is within about 20° of 90° or when C-S-S-C deviates by about 40° or more from 90°.
Journal of the American Chemical Society published new progress about 14807-75-1. 14807-75-1 belongs to ethers-buliding-blocks, auxiliary class Salt,Thiourea,Amine,Aliphatic hydrocarbon chain, name is Formamidine disulfide dihydrochloride, and the molecular formula is C2H8Cl2N4S2, Name: Formamidine disulfide dihydrochloride.
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https://en.wikipedia.org/wiki/Ether,
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