This paper reports the photochemical behaviour of unbridged (1-6) and bridged zirconocenes (7r, 7m), whose substituents differ in both electron-donor and steric properties. The study of the electronic spectra and EPR spin-trapping experiments showed the photogeneration of ligand- and zirconium-centred radicals at wavelengths higher than 350 nm. This feature makes these complexes suitable as photoiniti- ators for radical polymerisation processes. tert-Butyl acrylate polymerisation has been studied in detail and the results are particularly encouraging as far as the reaction yields and the stereochemistry are concerned. In particular, the complexes 4-6, due to the tuneability of their structure and their stability in solution, look the most promising reagents.
Zirconocenes as photoinitiators for free radical polymerisation of acrylates.
POLO, Eleonora;SOSTERO, Silvana;
2002
Abstract
This paper reports the photochemical behaviour of unbridged (1-6) and bridged zirconocenes (7r, 7m), whose substituents differ in both electron-donor and steric properties. The study of the electronic spectra and EPR spin-trapping experiments showed the photogeneration of ligand- and zirconium-centred radicals at wavelengths higher than 350 nm. This feature makes these complexes suitable as photoiniti- ators for radical polymerisation processes. tert-Butyl acrylate polymerisation has been studied in detail and the results are particularly encouraging as far as the reaction yields and the stereochemistry are concerned. In particular, the complexes 4-6, due to the tuneability of their structure and their stability in solution, look the most promising reagents.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
