Advancing photopolymerization and 3D printing: High-Performance Ni II complexes bearing N 2 O 2 Schiff-base ligands as photocatalysts

Author(s)

Pesqueira, Naralyne M. ; Morlet-Savary, Fabrice ; Schmitt, Michael ; Carvalho-Jr, Valdemiro P. ; Goi, Beatriz E. ; Lalevee, Jacques

• Document type: Journal article
• Source: EUROPEAN POLYMER JOURNAL; v. 216, p. 13-pg., 2024-07-03.

Abstract

New high-performance photocatalysts based on metal structures are being developed for polymerization. However, using low-cost metals while ensuring effectiveness is challenging. In this study, two Ni II complexes NiL1 and NiL2 were synthesized using N 2 O 2 Schiff-base ligands bearing pi-extended rings (naphthaldehyde ( H 2 L1 ) and phenylsalicylaldehyde ( H 2 L2 ) groups), respectively. These complexes were characterized by FTIR, UV-Vis and 1 H NMR spectroscopy, elemental analysis, cyclic voltammetry, and MALDI-TOF mass spectrometry. NiL1 and NiL2 were evaluated in photoinitiating system as new photocatalysts for the Free Radical Photopolymerization of Ethoxylated (3) Trimethylolpropane Triacrylate (TMPETA) for violet and green light. Threecomponent systems were employed in the presence of Di- tert-butyl-diphenyl iodonium hexafluorophosphate (Iod) and ethyl dimethylaminobenzoate (EDB). The absorption, luminescence, and redox properties of nickel complexes and ligands were explored and compared for a better understanding of their structure/reactivity relationship. The designed nickel complexes showed good photoinitiation abilities. NiL2 exhibited the highest monomer conversion, and it was investigated in the on-off process under green light irradiation, demonstrating the efficiency of the system in reactivating the polymerization process. An oxidative pathway mechanism was proposed based on free energy, steady state photolysis and electron spin resonance spin trapping experiments. The best system was successfully applied in cationic photopolymerization and 3D printing. (AU)

• FAPESP's process: 21/13128-1 - Development of new polymeric materials via coupling of mechanistically incompatible reactions using Ru/Pd and Ru/Ni heterobimetallic catalysts
• Grantee: Valdemiro Pereira de Carvalho Júnior
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/11873-1 - Organometallic complexes of Mn(II), Fe(II) and Ni(II) as CRP2 redox photocatalysts: new strategy for light curing with LEDs
• Grantee: Beatriz Eleutério Goi Carvalho
• Support Opportunities: Regular Research Grants
• FAPESP's process: 21/11741-8 - Ni(II) complexes for controlled radical photopolymerization reactions (photo-OMRP and CRP2) and application in 3D printing
• Grantee: Naralyne Martins Pesqueira
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 22/16213-2 - Controlled radical photopolymerization (CRP2) and 3D printing using novel Ni(II) complexes
• Grantee: Naralyne Martins Pesqueira
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate (Direct)