Comparison of the Thermal Stabilities of Diazonium Salts and Their Corresponding Triazenes

Abstract

A range of diazonium salts and their corresponding triazenes have been prepared in order to directly compare their relative thermal stabilities from differential scanning calorimetry (DSC) data. A structure-stability relationship (SSR) has been explored to investigate trends in stability, depending on the aromatic substituent and the structure of the secondary amine component of the diazonium salts and triazenes.All triazenes investigated show significantly greater stability (in many cases stable above 200 °C) compared to the corresponding diazonium salts, which show varying stabilities.

Aryne Generation from <i>o</i>-Triazenylarylboronic Acids Induced by Brønsted Acid

“…Plausible reaction mechanisms were shown in Charts 3a and 3b. With (±)-CSA, protonation of the terminal nitrogen atom of the triazenyl group lead to the elimination of diisopropylamine from 1 to form diazonium species I [24][25][26][27] (Chart 3a). Based on the Hammett plot analysis, the formation of I will be the rate-determining step.…”

Copper-Free Click Enabled Triazabutadiene for Bioorthogonal Protein Functionalization

“…Additionally, tyrosine is uncharged at physiological pH, and therefore, tyrosine modifications do not alter the surface charge of proteins in contrast to those that modify charged residues like lysine . As such, several new tyrosine conjugation strategies have been developed in the past decade including 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) and sulfur fluoride exchange (SuFeX) analogues, among others. − Such strategies have shown utility in a range of applications for protein modification and functionalization including manufacturing of antibody drug conjugates (ADCs). , Amidst the advances, the oldest tyrosine bioconjugation strategy, aryl diazonium ions to form azo-bonds, remains one of the most heavily utilized. , Though effective, aryl diazonium ions generally require generation under highly acidic conditions, and the salts are both prone to degradation and exhibit shock sensitivity, making long-term storage a challenge. , Further complicating storage, aryl diazonium ions are susceptible to hydrolysis at biologically relevant pH . Despite the limitations, aryl diazonium ions remain a quintessential tool within the realm of bioconjugate chemistry due to their reactivity and relative selectivity.…”

Suzuki Coupling of Activated Aryltriazenes for Practical Synthesis of Biaryls from Anilines

“…N,N ‐Dialkyl aryltriazenes have been well‐established to possess high thermal stability and chemical inertness under non‐acidic conditions [1] although the triazene moiety could be replaced by a variety of groups under catalytic or non‐catalytic conditions via in situ released diazonium species in the presence of stoichiometric amount of Brönsted or Lewis acids [2] . Obviously, the requirement of stoichiometric or even excess acid promotors would lead to limited functional group compatibility and low catalytic efficiencies of transition metal complex catalysts because of their competitive interaction with the Lewis basic groups in substrates and supporting ligands of the catalysts.…”