The synthesis and magnetic properties of carboxylic acid-derived 1,2,4-benzotriazinyl radicals and their coordination particles

Abstract

Stable magnetic coordination particles based on π-conjugated 1,2,4-benzotriazinyl radical ligands were synthesized using a sonochemical method.

Nanoparticles Containing Biocompatible Radicals Based on 1,2,4-Benzotriazinyl for Reactive Oxygen Species Scavenging in Living Cells

“…ESR spectroscopy was carried out to study the magnetic properties of VER and VAR . According to previous reports, , unpaired electrons of Blatter radical couples with three nitrogen atoms in the triazinyl ring, thereby seven-line patterns were observed in the solution ESR spectra of VER and VAR (Figure a,b), and the corresponding hyperfine coupling constant (hfcc) is summarized in Table S1.…”

“…Then, the single-line ESR signals were detected during the solid-state variable temperature (VT) ESR measurement in the range of 140–350 K (Figure ). The intensities of VER increase with increasing temperature up to 210 K and then reduce upon continuing heating to 350 K. In contrast, the intensities for VAR decline upon rising the temperature, and its line width is broader than that of VER due to the strong spin interaction resulting from intermolecular H-bond associations . Notably, in the whole applied temperature range, the half-field forbidden transition signals (Δms = ±2) were detected for VER and VAR , indicating the strong spin–spin interaction between adjacent radicals and the thermally populated spin-triplet state.…”

“…Moreover, the peaks exceeding 3100 cm –1 are not observed in FTIR spectra (Figure S15), suggesting no imino (−NH), and the precursor is completely converted to the radical form. In addition, the peaks located around 1700 and 2900 cm –1 correspond to the carbonyl and alkane chains, respectively . The carbonyl peak shifts from 1730 to 1690 cm –1 , revealing that VER is completely hydrolyzed to VAR .…”

“…The intensities of VER increase with increasing temperature up to 210 K and then reduce upon continuing heating to 350 K. In contrast, the intensities for VAR decline upon rising the temperature, and its line width is broader than that of VER due to the strong spin interaction resulting from intermolecular H-bond associations. 43 Notably, in the whole applied temperature range, the half-field forbidden transition signals (Δms = ±2) were detected for VER and VAR, indicating the strong spin−spin interaction between adjacent radicals and the thermally populated spin-triplet state. The intensities from the multiplied double integral ESR intensity with temperature declined when cooling these powder samples (Figure S17), disclosing their antiferromagnetic behavior.…”

“…In addition, the peaks located around 1700 and 2900 cm −1 correspond to the carbonyl and alkane chains, respectively. 43 The carbonyl peak shifts from 1730 to 1690 cm −1 , revealing that VER is completely hydrolyzed to VAR. Furthermore, the broad peaks from 2500 to 3200 cm −1 are assigned to the hydroxyl stretching vibration of hydrogen bond association in carboxylic acid.…”