Photo-induced organo-manganese-mediated radical polymerization of acrylates under LED irradiation

Autor(es)

Pesqueira, Naralyne M. ; Lira, Kathia H. ; Bignardi, Camila ; da Silva, Milene K. C. ; Silva, Thiago F. ; Machado, Antonio E. H. ; Nascimento, Otaciro R. ; Carvalho-Jr, Valdemiro P. ; Goi, Beatriz E.

• Tipo de documento: Artigo Científico
• Fonte: APPLIED ORGANOMETALLIC CHEMISTRY; v. 38, n. 7, p. 14-pg., 2024-04-28.

Resumo

The role of manganese in photo-induced organometallic-mediated radical polymerization (photo-OMRP) under LED (light-emitting diode) irradiation has not been previously explored. In this study, four manganese (II) complexes, namely [Mn(6-tert-butyl-N,N '-propanebis [salicylimine])] (Mn-Bu), [Mn(6,3-di-tert-butyl-N,N '-propanebis [salicylimine])] (Mn-Bu-2), [Mn(6-ethoxy-N,N '-propanebis [salicylimine])] (Mn-Ethoxy), and [Mn(6,3-di-ethoxy-N,N '-propanebis [salicylimine])] (Mn-Ethoxy(2)), were synthesized using both symmetrical and non-symmetrical tetradentate N2O2 Schiff base ligands. The Schiff base ligands were characterized by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), and nuclear magnetic resonance spectroscopy (NMR). The Mn (II) complexes were characterized by FTIR, UV-Vis, elemental analysis, molar conductivity, cyclic voltammetry, MALDI-TOF mass spectrometry, electron paramagnetic resonance, and rationalized with density functional theory (DFT) studies. All complexes were evaluated as photo-OMRP mediators under LED irradiation at 390 nm and in the 400-800 nm range. The photopolymerization utilized methyl acrylate (MA) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) in varying molar ratios of [MA]/[Mn-II]/[TPO] (900/1/1, 600/1/1, and 600/1/0.5). The photo-OMRP of MA mediated by Mn-Bu-2 showed the best control over molecular weight (M-n matching M-n,M-th) and dispersity (& ETH; < 1.30) at a [MA]/[Mn-II]/[TPO] = 600/1/0.5 M ratio. The polymerization system demonstrated a living character, as evidenced by reversible "on/off" light source switching. Furthermore, a block copolymer of poly (methyl acrylate)-b-poly (butyl acrylate) was successfully synthesized employing a sequential visible-light-induced process, with the Mn-Bu-2 system showing the best results. (AU)

• Processo FAPESP: 21/13128-1 - Desenvolvimento de novos materiais poliméricos via acoplamento de reações mecanisticamente incompatíveis usando catalisadores heterobimetálicos de Ru/Pd e Ru/Ni
• Beneficiário: Valdemiro Pereira de Carvalho Júnior
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 22/16571-6 - Complexos organometálicos de Mn (II), Fe (II) e Co (II) como fotocatalisadores redox da CRP2.
• Beneficiário: Camila Bignardi
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 21/11741-8 - Desenvolvimento de novos complexos de Ni(II) para reações de fotopolimerização radicalar controlada (foto-OMRP e CRP2) e aplicação em impressão 3D
• Beneficiário: Naralyne Martins Pesqueira
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 21/11873-1 - Complexos organometálicos de Mn(II), Fe(II) e Ni(II) como fotocatalisadores redox da CRP2: nova estratégia para fotopolimerização com LEDs
• Beneficiário: Beatriz Eleutério Goi Carvalho
• Modalidade de apoio: Auxílio à Pesquisa - Regular