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

Abstract

Thiocyameluric acidC 6 N 7 S 3 H 3 ,the tri-thio analogue of cyameluric acid, is ak ey compound for the synthesis of new s-heptazine (tri-s-triazine) derivatives. Here, two different routes for the synthesis of thiocyamelurica cid and its reaction to tris(aryldithio)-and tris(alkyldithio)cyamelurates C 6 N 7 (SSR) 3 are reported as well as transformation to alkali metal thiocyamelurates M 3 [C 6 N 7 S 3 ], M= Na, K. Thesec ompoundsw ere characterisedb yF TIR, Raman, solution 13 Ca nd 1 HNMR spectroscopies, thermal gravimetric analysis( TGA) and elementala nalysis. The three (de)protonation steps of thiocyamelurica cid were investigated by acid-base titration followed via UV/Vis absorptions pectroscopy.W hile it was not possible to determine the three pK a values, it could be postulated that the acid strength probably increases in the following order:cyanuric acid (C 3 N 3 O 3 H 3 ) < thiocyanuric acid (C 3 N 3 S 3 H 3 ) < cyameluric acid (C 6 N 7 O 3 H 3 ) < thiocyameluric acid (C 6 N 7 S 3 H 3 ). Single crystalso fN a 3 [C 6 N 7 S 3 ]·10 H 2 Oa nd K 3 [C 6 N 7 S 3 ]·6 H 2 Ow ere obtained and the structures analyzed by single crystal X-ray diffraction. Additionally,q uantum chemicalc alculationsw ere performed to get insights into the electronic structure of thiocyameluric acid and to clarify the thiol-thione tautomerism.B ased on ac omparison of calculated and measuredv ibrational spectra it can be concluded that thiocyamelurica cid and the di-and mono-protonated anionsexist in the thione form.Scheme1.Principalstructures of the s-triazine derived cyanurates [C 3 N 3 O 3 ] 3À ,a nd the s-heptazine derived cyamelurates [C 6 N 7 O 3 ] 3À and their thio analogues. For ab etterc omparisonw ith cyameluricacid andcyamelurates we named 2,5,8-trimeracpto-tri-s-triazine and its derivatives thiocyameluric acid, thiocyameluratesa nd the disulfidesa re named dithiocyamelurates.[a] C.Supporting Information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.

Triangular boron carbon nitrides: an unexplored family of chromophores with unique properties for photocatalysis and optoelectronics

“…2 Melem (triamino-Hz), cyameluric acid (trihydroxy-Hz) and cyameluric chloride (trichloro-heptazine) are well-known derivatives of Hz. 3 More recently, new derivatives of Hz were synthesized [4][5][6] and their use as emitters in organic light-emitting diodes (OLEDs) [7][8][9] or as photoredox catalysts were explored. 10,11 A comprehensive up-to-date account of the literature on molecular (monomeric) Hz and derivatives thereof can be found in Ref.…”