Tetrathiaselenepin Ring Fused to Benzene and Naphthalene

Abstract

Benzo[1,2,3,4,5]tetrathiaselenepin is an unstable cyclic polychalcogenide. Isopropyl and/or methoxy groups at the neighboring of polychalcogen ring sterically stabilized the unstable ring. Replacing of aromatic unit from benzene to naphthalene also gave thermodynamic stability to the ring. Synthesis, characterization, and stability of some novel polychalcogenides are reported.

Selenium‐Containing Tetrachalcogenins and Pentachalcogenepins Fused to Aromatic Systems

“…By the similar reaction, 6f and 7f were also obtained in 46 and 29 % yields, respectively. The experimental findings ( Table 1) clearly implied that [1,2,3,4,5]tetrathiaselenepin and [2,3,4,1,5]trithiadiselenepin rings were unstable on benzo-fused derivatives, but benzene derivatives substituted at the neighboring positions of the chalcogen ring prevented the rings from usual degradation.…”

“…[1,2] The synthetic usefulness of benzopolysulfides was initiated in 1971 from the pioneering research of Fehér and Langer. [3] Relative to the syntheses and reactions of linear or cyclic polysulfides, only a few examples of cyclic polychalcogenides containing selenium have been reported.…”

“…It is the first isolated trichalcogenole having one selenium atom, which is stabilized by an extended π system. Phenanthro [9,10-f] [1,2,3,4,5]tetrathiaselenepin is stable in the solid state. The use of polar solvents under ambient conditions resulted in the extrusion of selenium from the ring to generate more stable trithiole rings.…”

“…Although there is a lot of theoretical and experimental evidence and many reports on the stabilization of cyclic benzopolysulfides (o-C 6 H 4 S x , where x = 2-8), [8] only a few reports deal with the analogous six-and seven-membered benzopolychalcogenides containing selenium. [1] Five-membered benzotrichalcogenoles showed well-defined chemical and electrochemical redox behaviors and all compounds were extensively studied. [9] In other words, seven-membered rings are of great interest owing to their diversity in nature and cytotoxic activity.…”

“…[9a] The precursors, benzo [1,3,2]thiaselenastannoles (5a-d) and benzo [1,3,2]diselenastannoles (5e-g) were prepared according to the reported procedures (Scheme 1, Table 1). …”