Abstract
Four nickel(II) complexes with symmetrically substituted N2O2 tetradentate Schiff-base ligands, prepared from the 2:1 condensation of 3-tert-butyl-salicylaldehyde, and ethylenediamine (1), o-phenylenediamine (2), 1,2-cis,trans-cyclohexyldiamine (3), or 1,3-diaminepropane (4), were synthesized. These NiII Schiff-base complexes (1–4) were used as control agents for the polymerization of vinyl acetate (VAc) photoinitiated by diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) according to a photoinduced organometallic-mediated radical polymerization (photo-OMRP) mechanism. All complexes presented good control ability, although the polymerization mediated by 3 showed the best control over molecular weight (Mn matching Mn,th) and dispersity (Ð < 1.50). The livingness of the polymers has been confirmed by LED on and LED off experiments, the polymerization stopped immediately, and no monomer conversion was observed during the light-off period, indicating a negligible concentration of the active radical in the dark. Further, to demonstrate the living nature of this system, block copolymers of poly(vinyl acetate)-b-poly(methyl acrylate) were synthesized using the sequential visible-light-induced process. Kinetic results and computational investigations supported the activation/deactivation equilibrium exerted by complexes 1–4, which occurred on only one face of the complexes via reversible deactivation (RD) mechanism.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Photochemistry and Photobiology A: Chemistry
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.