Three poly(arylmethyl) quartet triradicals and three quintet tetraradicals are prepared by oxidation of the corresponding carbanions. The ground states for polyradicals in frozen solutions are established using ESR spectroscopy (4–100 K), including Curie plots (10–80 K), and SQUID magnetometry (2–80 K). For two triradicals and one tetraradical, ESR Δms = 2 transitions are resolved; for one triradical, the Δms = 3 transition is observed. The i-Pr-substituted triradical and tetraradical are isolated as solids and studied using SQUID; thermal population of low spin states is negligible at ambient temperature. The most intense bands in the UV-vis spectra for i-Pr-substituted tri- and tetraradicals are similar to those found in the homologous diradicals. Electrochemical study of the i-Pr-substituted triradical at 195–200 K reveals three reversible voltammetric waves (peaks) that correspond to three one-electron reductions to the corresponding trianion.
ASJC Scopus subject areas
- Colloid and Surface Chemistry