Sulfides and Disulfides of s‐Triazine: Potential Thermal Thiyl Radical Generators

Abstract

A series of aliphatic and aromatic thioethers and dithioethers of s-triazine were synthesised to study their thermal properties, in particular the thermally induced thiyl radical generation ability. Four symmetric s-triazine sulfides of the type (RS) C N , namely 2,4,6-tris(phenylthio)- (1), 2,4,6-tris(para-tolylthio)- (3), 2,4,6-tris(ethylthio)- (5) and 2,4,6-tris(tert-butylthio)-1,3,5-triazine (7), as well as four symmetric s-triazine disulfides of the type (RSS) C N , namely 2,4,6-tris(phenyldithio)- (2), 2,4,6-tris(para-tolyldithio)- (4), 2,4,6-tris(ethyldithio)- (6) and 2,4,6-tris(tert-butyldithio)-1,3,5-triazine (8) were synthesised. All compounds were comprehensively characterised by H and C NMR, infrared and Raman spectroscopy as well as elemental analyses. Single-crystal X-ray diffraction analyses of 1, 2 and 5 are discussed. The thermal behaviour was studied by thermogravimetric analyses coupled with mass spectrometry (TGA-MS) and quantum chemical calculations. Limiting oxygen index (LOI) flammability tests showed that the disulfides are the most promising radical generators, and are most likely suitable flame retardants for selected polymers.

Large‐Scale Synthesis of a New Polymeric Carbon Nitride—C3N3 with Good Photoelectrochemical Performance

“…[ 13,14 ] This problem is probably due to the lack of error‐correction based on reported monomers (Figure 1b). [ 15 ] Different from reported monomers, Ullmann reaction may produce C 3 N 3 from C 3 N 3 Cl in large‐scale with reasonable crystallinity based on following reasons: (1) the formatted CC bond may be reversible at reaction temperature because triazine is a strong electro‐withdraw group (Figure 1c; Figure S1, Supporting Information), [ 16 ] so as to facilitate error‐correction and give large‐sized product; [ 17 ] (2) copper can migrate in the product's matrix (Figure S2, Supporting Information) so as to self‐templatedly grow C 3 N 3 layer‐by‐layer; (3) boiling temperature of C 3 N 3 Cl 3 is 194 °C so that homogenous polymer film can grow in the vapor of C 3 N 3 Cl 3 without ultrahigh vacuum condition. [ 18 ]…”

Covalent Scrambling in Porous Polyarylthioethers through a Stepwise SNAr for Tunable Bandgap and Porosity

“…[17] Notably, a minor disulfide functional group was observed by the FT-Raman spectroscopy, presumably due to partial oxidation of thiolate during the reaction (Figure S7). [21] According to the amount of residual fluorine, FS-POP-2 prepared at < 153 °C exhibited a fluorine content between the theoretical values for tetra-and hexasubstituted structures. In contrast, FS-POP-2 prepared at temperatures > 163 °C showed an increase in carbon content, even higher than the theoretical carbon content of octasubstituted structure 5, indicating partial carbonization/decomposition of the polymer under high-temperature conditions.…”

“…The FT‐IR spectra of FS‐POP‐2 showed the gradual evolution of the C−S peaks at 1040 and 680 cm −1 upon increasing the reaction temperature, corresponding to increasing sulfur content (Figure S6) [17] . Notably, a minor disulfide functional group was observed by the FT‐Raman spectroscopy, presumably due to partial oxidation of thiolate during the reaction (Figure S7) [21] . According to the amount of residual fluorine, FS‐POP‐2 prepared at <153 °C exhibited a fluorine content between the theoretical values for tetra‐ and hexa‐substituted structures.…”

Synthesis of Thiocyameluric Acid C6N7S3H3, Its Reaction to Alkali Metal Thiocyamelurates and Organic Tris(dithio)cyamelurates

“…The reaction with sulfenyl chlorids leads to dithiocyanurates. These compounds proved to be promising flame retardants for polypropylene . The s ‐heptazine derivatives show flame retardant effects, but the high thermal stability is assumed to prevent the release of higher amounts of flame retarding thiyl radical species during the decomposition of polypropylene matrix.…”

“…These compounds provedt ob ep romising flame retardants for polypropylene. [23,32] The s-heptazine derivativess how flame retardante ffects, but the high thermals tability is assumed to preventt he releaseo fh ighera mounts of flame retarding thiyl radicals pecies during the decomposition of polypropylene matrix. The organic dithiocyanurates C 3 N 3 (SSR) 3 ,s how promising effectsi n contrastt ot heir analogous thiocyanurate derivatives C 3 N 3 (SR) 3 .…”