Abstract
AbstractAt least three kinds of stable paramagnetic species are formed in films of poly(triphenylcarbinol) 1 upon thermolysis in vacuo up to 500°C. “Low temperature” radicals of triarylmethyl type (RTAMT1) are created in the 120 ÷ 220°C temperature region. These radicals give rise to a symmetric ESR signal (g = 2.0026 ± 0.0003; ΔH ≈ 1.0 mT) with poorly resolved hyperfine structure and to an absorption band (AB) of allowed transition with λmax = 407 nm in UV spectra. The spectral region of forbidden transitions, assumed for the RTAMT1, is masked by a nonradical AB, in particular by that of quinoid structure of Chichibabin hydrocarbon type with λmax = 595 nm. From 220°C to 280°C the “high temperature” radicals RTAMT2 appear, with a strong bathochromic shifted AB of forbidden transition (λmax = 710 nm). Maximum concentration of RTAMT2 (≈︁1020 spin/g) is achieved at ≈︁280°C. Possible structures of both kinds of RTAMT are discussed. At T ≥ 300°C paramagnetic species that differ from RTAMT are formed in 1.
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