Surface grafting of cobalt complexes on polymeric supports: Evidence for site isolation and applications to reversible dioxygen binding
✍ Scribed by Anjal C. Sharma; Vivek Joshi; A. S. Borovik
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 190 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
Imprinted polymers were synthesized using the surface-grafting technique with [Co(III)1(vpy)(dmap)]PF 6 {1, bis[2-hydroxy-4-(4-vinylbenzyloxy)benzaldehyde]ethylene-diimine; vpy: 4-vinylpyridine; dmap: N,NЈ-dimethyl-4-aminopyri-dine} as the template. The metallated sites were probed using spectroscopic techniques including UV-vis, Fourier transform infrared, and electron paramagnetic resonance (EPR) spectroscopies to investigate the site architecture and isolation of the immobilized sites in the surface-grafted polymers. EPR studies showed a distribution of four and five coordinated sites similar to the bulk copolymers, and the surface-grafted polymer showed reversible binding to dioxygen in multiple cycles. Both results indicated site isolation in the surface-grafted polymers analogous to the bulk polymers. Although the dioxygen binding in surface-grafted polymers is reversible, the spin density decreases to 50% in the third cycle as opposed to bulk copolymers. This indicates that the sites are more heterogeneous and more exposed to the environment than the analogous sites in bulk copolymers.