Struktur der Blei(IV)‐carboxylate und ihre Zersetzung über elektronenspinresonanz‐spektroskopisch nachweisbare Radikalzwischenstufen

The position of the asymmetric COO‐ vibration of lead 4+ carboxylates (at 6.50 to 6.58 μ) clearly indicates the absence of covalent bonding between oxygen and lead. These salts show strong UV. absorption in the region of 220 to 270 nm which is assigned to a charge transfer from oxygen to lead. UV.‐irradiation of lead 4+ carboxylates at −196°C in a solid benzene matrix leads to decarboxylation and production of alkyl radicals which were identified by ESR. spectrometry. These radicals react in the solid matrix by hydrogen abstraction from the α‐position of a neighbouring carboxylate. In solution however rapid oxidation to carbonium ions occurs.