Generalized synthesis and physical properties of dialkoxy disulfides

A substrate study was undertaken in order to probe the scope of S2Cl2 coupling of alcohols to form dialkoxy disulfides. Compounds 1b and 1f are new; along with 1a, 1c, 1h, and 1j, all of the title compounds are fully characterized, and the yields of la and 1c have been optimized from previously reported syntheses. The effect of the R-substituent about the OSSO moiety has been carefully probed as yields vary. A substrate and a solvent study of the coalescence behavior of this class was carried out. The origin of the inherently large barrier to rotation and the resultant thermal decomposition pathway is discussed. Both phenomena are shown to be solvent independent; hindered rotation is substrate independent. The decomposition of la is ca. 7 kcal/mol higher than the barrier to rotation about the S-S bond. The combined evidence suggests acyclic unsymmetric homolytic cleavage of the dialkoxy disulfide.</p

Optimization of the synthesis of symmetric aromatic tri- and tetrasulfides

The reaction of aromatic thiols with sulfur dichloride and sulfur monochloride to form the corresponding aromatic trisulfides, 2a-d, and tetrasulfides, 3a-d, has been optimized with respect to yield and purity. The use of pyridine as an amine base and the use of freshly distilled sulfur monochloride (S2Cl2) serve as important alterations to the synthetic method. Their physical properties have been characterized, revealing some discrepancies with the literature.</p

Synthesis of new cyclic thionosulfites

The reaction of a series of 1,2-diols with S2Cl2, 1,1'-thiobisbenzimidazole (4a), and 1,1'-dithiobisbenzimidazole (4b) provides the corresponding thionosulfites, ROS(S)OR (2), in moderate to good yield.</p

Crossover point between dialkoxy disulfides (ROSSOR) and thionosulfites ((RO)(2)S=S): Prediction, synthesis, and structure

Isomeric preference between cyclic dialkoxy disulfides and thionosulfites is governed by the ring size of the heterocycle. Rings smaller than seven atoms prefer the thionosulfite connectivity, whereas larger rings or acyclic analogues favor the unbranched dialkoxy disulfide structure. Density functional calculations were employed to predict the crossover point at which both constitutional isomers are of comparable stability. Follow-up synthesis provides the previously unknown eight-membered ring dialkoxy disulficle 14 and seven-membered ring thionosulfite 15 from the same reaction. X-ray crystallography for all but one of the reaction products and complementary NMR analysis furnishes insights into both solid-state and solution conformations. A long-standing issue regarding the concerted vs catalyzed isomerization pathway between XSSX and X2S = S has been addressed for X = RO and shown to be acid dependent.</p

Outsmarting Proctors with Smartwatches: A Case Study on Wearable Computing Security

Abstract. Many companies have recently started to offer wearable computing devices including glasses, bracelets, and watches. While this technology enables exciting new applications, it also poses new security and privacy concerns. In this work, we explore these implications and analyze the impact of one of the first networked wearable devices—smartwatches— on an academic environment. As a proof of concept, we develop an application for the Pebble smartwatch called ConTest that would allow dishonest students to inconspicuously collaborate on multiple-choice exams in real time, using a cloud-based service, a smartphone, and a client application on a smartwatch. We discuss the broader implications of this technology, suggest hardware and software approaches that can be used to prevent such attacks, and pose questions for future research