16778-70-4Relevant articles and documents
Physicochemical and thermal properties for a series of 1-alkyl-4-methyl-1, 2,4-triazolium bis(trifluoromethylsulfonyl)imide ionic liquids
De La Hoz, Andreah T.,Brauer, Ulises G.,Miller, Kevin M.
, p. 9944 - 9951 (2014)
Physicochemical properties and long-term thermal stabilities are reported for a series of 1-alkyl-4-methyl-1,2,4-triazolium [NTf2] ionic liquids, and a Walden plot analysis was conducted in order to determine the ionicity of these materials. In general, viscosities were found to increase with increasing alkyl chain length while densities and molar conductivities were found to decrease. The 1,2,4-triazolium ionic liquids were classified as "good" ionic liquids after analysis of the Walden plot; however, they did not perform as well as the standard imidazolium ionic liquid [bmim][NTf 2]. Thermal properties from DSC and TGA experiments were also completed. 1,2,4-Triazolium ionic liquids with an alkyl chain length of octyl (C8) or less exhibited a single Tg transition below ?70 °C; however, the decyl (C10) and dodecyl (C12) systems exhibited a Tm value. No correlation between Tonset or Td5% and alkyl chain length was observed during short-term, temperature-ramped TGA experiments. However, long-term, isothermal TGA studies indicated a general increase in T0.01/10 value as the alkyl chain length increased. Both short- and long-term TGA studies indicated that the 1,2,4-triazolium ionic liquids were not as thermally stable as the model imidazolium ionic liquid [bmim][NTf 2].
Silver complexes of 1,2,4-triazole derived N-heterocyclic carbenes: Synthesis, structure and reactivity studies
Dash, Chandrakanta,Shaikh, Mobin M.,Ghosh, Prasenjit
, p. 97 - 106 (2011)
Two silver(I) complexes {[1-R-4-(N-t-butylacetamido)-1,2,4-triazol-5- ylidene]2Ag}+ Cl- [R = Et (1b), i-Pr (2b)] of N/O-functionalized N-heterocyclic carbenes derived from 1,2,4-triazoles are reported. The silver complexes, 1b and 2b, have been synthesized from the reaction of the N/O-functionalized triazolium chloride salts namely, 1-R-4-(N-t-butylacetamido)-1,2,4-triazolium chloride [R = Et (1a), i-Pr (2a)] by treatment with Ag2O in 53-56% yield. The 1,2,4-triazolium chloride salts 1a and 2a were prepared by the alkylation reaction of 1-R-1,2,4-triazole (R = Et, i-Pr) with N-t-butyl-2-chloro acetamide in 47-63% yield. The molecular structures of the silver(I) complexes, 1b and 2b, have been determined by X-ray diffraction studies. The density functional theory studies on the silver 1b and 2b complexes suggest that the 1,2,4-triazole derived N-heterocyclic carbenes to be strong σ-donating ligands similar to the now much recognized imidazolebased N-heterocyclic carbenes. The reactivity studies with (SMe 2)AuCl and (SMe2)CuBr indicated the silver complexes, 1b and 2b, to be good transmetallating agents. Indian Academy of Sciences.
Taming Ambident Triazole Anions: Regioselective Ion Pairing Catalyzes Direct N-Alkylation with Atypical Regioselectivity
Dale, Harvey J.A.,Hodges, George R.,Lloyd-Jones, Guy C.
, p. 7181 - 7193 (2019/05/10)
Controlling the regioselectivity of ambident nucleophiles toward alkylating agents is a fundamental problem in heterocyclic chemistry. Unsubstituted triazoles are particularly challenging, often requiring inefficient stepwise protection-deprotection strategies and prefunctionalization protocols. Herein we report on the alkylation of archetypal ambident 1,2,4-triazole, 1,2,3-triazole, and their anions, analyzed by in situ 1H/19F NMR, kinetic modeling, diffusion-ordered NMR spectroscopy, X-ray crystallography, highly correlated coupled-cluster computations [CCSD(T)-F12, DF-LCCSD(T)-F12, DLPNO-CCSD(T)], and Marcus theory. The resulting mechanistic insights allow design of an organocatalytic methodology for ambident control in the direct N-alkylation of unsubstituted triazole anions. Amidinium and guanidinium receptors are shown to act as strongly coordinating phase-transfer organocatalysts, shuttling triazolate anions into solution. The intimate ion pairs formed in solution retain the reactivity of liberated triazole anions but, by virtue of highly regioselective ion pairing, exhibit alkylation selectivities that are completely inverted (1,2,4-triazole) or substantially enhanced (1,2,3-triazole) compared to the parent anions. The methodology allows direct access to 4-alkyl-1,2,4-triazoles (rr up to 94:6) and 1-alkyl-1,2,3-triazoles (rr up to 99:1) in one step. Regioselective ion pairing acts in effect as a noncovalent in situ protection mechanism, a concept that may have broader application in the control of ambident systems.
Correlating structure with thermal properties for a series of 1-alkyl-4-methyl-1,2,4-triazolium ionic liquids
Daily, Lucas A.,Miller, Kevin M.
, p. 4196 - 4201 (2013/06/04)
Thermal properties (Tm and Td) are reported for a series of 1-alkyl-4-methyl-1,2,4-triazolium ionic liquids where the alkyl chain length R and anion [X-] were varied. The highest melting transitions were observed when a lo
