Pesquisa e projetos

Research and projects

Orientadores dos projetos de pesquisa/ Research supervisors

Orientadora/Supervisor: Beatriz Eleutério Goi

France Supervisor: Jacques Lalevée

Coorientador/Co-supervisor: Valdemiro Pereira de Carvalho Júnior

Grupo de pesquisa/Research group: Lacom

Projeto 1

Síntese de novos complexos organometálicos de Ni(III) coordenados a bases de Schiff assimétricas para mediar a foto-OMRP

Resumo: Complexos organometálicos Ni(III) serão sintetizados para mediar/controlar reações de fotopolimerização radicalar mediada por organometálicos – foto-OMRP (Organometallic-Mediated Radical Polymerization). A proposta foi avaliar sistematicamente diferentes combinações de ligantes ancilares coordenados ao níquel e, consequentemente, alcançar um ajuste fino através da variação das contribuições eletrônicas e estéricas no centro metálico, direcionando a reatividade desses complexos organometálicos para atuar eficientemente na reação de foto-OMRP. Os ligantes avaliados foram diferentes bases de Schiff simétricas e não simétricas coordenadas ao centro metálico de Ni frente a polimerização de monômeros vinílicos via foto-OMRP. A proposta se estendeu em três etapas, as quais estão completamente interligadas no processo de desenvolvimento. Inicialmente, a atenção foi direcionada à síntese de bases de Schiff tetradentadas. A segunda etapa foi voltada para a síntese dos complexos de Ni(II) coordenados aos diferentes ligantes bases de Schiff. A terceira etapa foi dedicada à avaliação da eficiência dos complexos de Ni(II) na reação de foto-OMRP. A última etapa teve como objetivo selecionar os complexos de Ni(II) com os melhores desempenhos e submetê-los a uma reação de adição com o radical gerado pela clivagem fotoquímica de um iniciador para se obter os complexos organometálicos(III). Pretendeu-se, com isso, estabelecer fundamentos para a compreensão do desempenho dos mediadores, bem como da formação dos intermediários de reação envolvidos em cada reação possibilitando o planejamento de sistemas que combinem reatividade e seletividade para a síntese de novos materiais com arquitetura diferenciada via foto-OMRP.

Esse projeto foi desenvolvido durante a minha iniciação científica com bolsa FAPESP (2019 -2022). A divulgação científica ocorreu através de participação em congressos científicos, publicação de resumos e apresentações na forma poster e oral. Vale ressaltar que nessa época a maioria dos congressos ocorreram na forma on-line por causa da pandemia da COVID-19, mas isso não impediu que a divulgação científica não ocorresse.

Após os quatro anos de graduação em Química e realização de iniciação científica no Laboratório de Catálise Organometálica e Materiais na FCT-UNESP, um artigo científico foi publicado no Journal of Photochemistry and Photobiology A: Chemistry.

Além disso, eu colaborei em mais dois trabalhos publicados na área de fotopolimerização radicalar controlada usando complexos de Co(II) coordenados por bases de Schiff como mediadores da foto-OMRP.

Project 1

Synthesis of new organometallic complexes of Ni(III) bearing asymmetric Schiff bases to mediate the photoinitiated radical polymerization

Abstract: Organometallic complexes of NiIII were synthesized to mediate/control organometallic-mediated radical photopolymerization reactions - Photo-OMRP (Organometallic-Mediated Radical Polymerization). The proposal was systematically evaluated different combinations of coordinate ancillary binders to different transition metals and, consequently, to achieve a fine adjustment through the variation of the electronic and steric contributions in the metallic center, directing the reactivity of these organometallic complexes to act efficiently in the photo- OMRP. The binders evaluated were different unpublished asymmetric Schiff bases coordinated to the metal center of Ni versus the polymerization of vinyl monomers via photo-OMRP. The proposal extends in three stages, which were completely interconnected in the development process. Initially, the attention was focused on the synthesis of tetradentate asymmetric Schiff bases. The second step was focused on the synthesis of the Ni(II) complexes coordinated with the different Schiff base ligands. The third step was dedicated to the evaluation of the efficiency of Ni(II) complexes in the photo-OMRP reaction. The final step was selected the Ni(II) complexes with the best performances and submit them to an addition reaction with the radical generated by the photochemical cleavage of a symmetric primer for obtain the organometallic complexes(III). It was intended, therefore, to establish fundamentals for the understanding of the performance of the mediators, as well as the formation of the reaction intermediates involved in each reaction, allowing the planning of systems that combine reactivity and selectivity for the synthesis of new materials with differentiated architecture via photo -OMRP

This project was developed during my undergraduate research with a FAPESP scholarship (2019–2022). The scientific dissemination included participation in conferences, abstract publications, and both poster and oral presentations. It is worth noting that, at the time, most conferences were held online due to the COVID-19 pandemic, but this did not hinder the dissemination of research.

After four years of studying Chemistry and conducting research at the Laboratory of Organometallic Catalysis and Materials (LaCOM) at FCT-UNESP, a scientific article was published in the Journal of Photochemistry and Photobiology A: Chemistry.

Additionally, I contributed to two other published studies on controlled radical photopolymerization using Co(II) complexes coordinated by Schiff bases as photo-OMRP mediators.

Artigo/Article: Visible light-induced radical polymerization of vinyl acetate mediated by organo-nickel N2O2 Schiff-base complexes

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.

DOI: https://doi.org/10.1016/j.jphotochem.2022.114443

Artigo/Article: Photocontrolled reversible-deactivation radical polymerization of butyl acrylate mediated by Salen-type CoII complexes

Abstract

In this study, we synthesized the complex [Co(BuSalen)] using the novel tetradentate BuSalen ligand and analyzed its ability as a controlling agent for the photo-induced organometallic-mediated radical polymerization (photo-OMRP) of butyl acrylate (BA) using diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as photo-initiator. BA polymerization with [Co(BuSalen)] reached significant control levels using the [BA]/[CoII]/TPO molar ratio of 600/1/1. The [Co(Salen)] and [Co(Bu2Salen)] complexes were also obtained following literature methods aiming a comparison in the mediating ability in photo-OMRP. [Co(BuSalen)] and [Co(Bu2Salen)] showed better controlling ability, as observed in the copolymerization study (Đ= 2.64, 1.50, and 1.26 for complexes [Co(Salen)], [Co(BuSalen)] and [Co(Bu2Salen)], respectively). Kinetics studies and computational investigations support a reversible termination (RT) mechanism and a tailorable CoII complex reactivity mainly altered by Schiff-base steric factors. Calculated thermodynamic parameters agree with the controlling degree delivered by these complexes, since the polymerization control increases with increasing the ΔG values for the formation of dormant species.

DOI: https://doi.org/10.1016/j.eurpolymj.2021.110757

Artigo/Article: Photoinduced organometallic mediating radical polymerization of acrylates mediated by CoII complexes of non-symmetrical tetradentate Schiff-base ligands

Abstract

Three new cobalt(II) complexes with non-symmetrically-substituted N2O2 tetradentate Schiff-base ligands, prepared from the 1:1:1 condensation of 3-etoxy-salicylaldehyde, salicylaldehyde and ethylenediamine (H2Etsal − 1), o-phenylenediamine (H2Phsal − 2) or 1,2-cis,trans-cyclohexyldiamine (H2Cysal − 3), were synthesized. The complexes 1–3 were characterized by UV–Vis, FTIR, and MALDI-TOF spectroscopy, elemental analysis, molar conductance, cyclic voltammetry, and computational methods. The CoII-Schiff-base complexes (1–3) were used as controlling agents for the polymerization of n-butyl acrylate (BA) photoinitiated by diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), according to an organometallic-mediated radical polymerization (OMRP) mechanism. Although, all complexes have presented good control ability, the polymerization mediated by complex 1 showed the best control over molecular weight (Mn matching with Mn,th) and dispersity (Ð < 1.50). Kinetic results and computational investigations support the activation/deactivation equilibrium, exerted by complexes 1–3, occurring by one face of the complexes via reversible termination (RT) mechanism.minim.

DOI: https://doi.org/10.1016/j.jphotochem.2021.113595

Projeto 2

Desenvolvimento de novos complexos de Ni(II) para reações de fotopolimerização radicalar controlada (foto-OMRP e CRP2) e aplicação em impressão 3D

Resumo: Complexos metálicos de Ni(II) têm sido sintetizados para catalisar/controlar reações de fotopolimerização radicalar. A proposta se estende em três etapas, as quais estão completamente interligadas no processo de desenvolvimento. Inicialmente, a atenção está sendo direcionada à síntese dos ligantes bases de Schiff e NHCs não simétricos e dos respectivos complexos de Ni(II), envolvendo toda a parte de caracterização através das técnicas de FTIR, UV-Vis, EPR, RMN 1H e 13C, análise elementar e espectrometria de massas. A segunda etapa foi dedicada à avaliação das propriedades fotoquímicas dos complexos sintetizados com os ligantes bases de Schiff e com os ligantes NHCs tendo em vista a aplicação em sistemas fotoiniciadores da fotopolimerização radicalar controlada (CRP2) e livre (FRP). A terceira etapa está dedicada à avaliação dos complexos de Ni(II) como mediadores da foto-OMRP e fotocatalisadores redox da CRP2 utilizando os monômeros acetato de vinila, acrilato de metila, acrilato de butila e metacrilato de metila. Na CRP2, os fotocatalisadores redox de Ni(II) estão sendo estudados na presença de brometo de fenacila e da amina EDB sob irradiação de LEDs. Também será avaliada a copolimerização dos monômeros selecionados utilizando os sistemas fotoiniciadores mais eficientes no fotocontrole da homopolimerização e também a aplicação em impressão 3D baseada na estereolitografia. Pretende-se, com isso, alcançar um ajuste fino das propriedades eletrônicas, eletroquímicas e estéricas na esfera de coordenação dos complexos metálicos de Ni(II) através da combinação dos ligantes ancilares, de modo a encontrar a reatividade ideal para promover uma eficiência satisfatória nessa reação.

Esse projeto está sendo desenvolvido durante o meu doutorado direto com bolsa FAPESP (2022-atual). A divulgação científica ocorreu através de participação em congressos científicos, publicação de resumos e apresentações na forma poster e oral, além da publicação de artigos científicos. Uma parte desse projeto foi desenvolvida na França durante um ano com bolsa BEPE FAPESP em parceria com o Prof. Dr. Jacques Lalevée.

Além disso, eu colaborei em mais três trabalhos publicados na área de fotopolimerização radicalar controlada usando complexos de Co(II) coordenados por bases de Schiff como mediadores da foto-OMRP e complexo de Fe(III) coordenados por ligantes NHC como mediador da foto-ATRP.

Project 2

Ni(II) complexes for controlled radical photopolymerization reactions (photo-OMRP and CRP2) and application in 3D printing

Abstract: Ni(II) metal complexes have been synthesized to catalyze and control radical photopolymerization reactions. The project is structured into three interconnected stages. Initially, the focus is on the synthesis of Schiff base and asymmetric NHC ligands, as well as their corresponding Ni(II) complexes, with detailed characterization using FTIR, UV-Vis, EPR, 1H^1H1H and 13C^13C13C NMR, elemental analysis, and mass spectrometry.

The second stage involves evaluating the photochemical properties of the synthesized complexes for their application in photoinitiating systems for controlled radical photopolymerization (CRP2) and free-radical photopolymerization (FRP). The third stage is dedicated to investigating Ni(II) complexes as mediators in photo-OMRP and redox photoinitiators in CRP2, using vinyl acetate, methyl acrylate, butyl acrylate, and methyl methacrylate monomers.

In CRP2, Ni(II) redox photoinitiators are being studied in the presence of phenacyl bromide and the EDB amine under LED irradiation. Additionally, the copolymerization of selected monomers will be evaluated using the most efficient photoinitiating systems for controlled homopolymerization, as well as their application in 3D printing based on stereolithography. The goal is to fine-tune the electronic, electrochemical, and steric properties within the coordination sphere of the Ni(II) complexes by combining ancillary ligands, aiming to achieve optimal reactivity and satisfactory efficiency in these reactions.

This project is being developed as part of my direct PhD with a FAPESP fellowship (2022–present). Scientific dissemination has been carried out through participation in scientific conferences, the publication of abstracts, oral and poster presentations, and research articles. Part of this project was conducted in France for one year with a BEPE-FAPESP scholarship in collaboration with Prof. Dr. Jacques Lalevée.

Additionally, I have contributed to three published studies in the field of controlled radical photopolymerization using Co(II) complexes coordinated by Schiff bases as photo-OMRP mediators and Fe(III) complexes coordinated by NHC ligands as photo-ATRP mediators.

Artigo/Article: Photo-induced organo-manganese-mediated radical polymerization of acrylates under LED irradiation

Abstract

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-Bu2), [Mn(6-ethoxy-N,N′-propanebis [salicylimine])] (Mn-Ethoxy), and [Mn(6,3-di-ethoxy-N,N′-propanebis [salicylimine])] (Mn-Ethoxy2), 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]/[MnII]/[TPO] (900/1/1, 600/1/1, and 600/1/0.5). The photo-OMRP of MA mediated by Mn-Bu2 showed the best control over molecular weight (Mn matching Mn,th) and dispersity (Ð < 1.30) at a [MA]/[MnII]/[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-Bu2 system showing the best results.

DOI: https://doi.org/10.1002/aoc.7495

Artigo/Article: Well-defined non-symmetric NHC-iron(III) catalyst for photoinduced atom-transfer radical polymerization of methyl methacrylate

Abstract

Photoinduced atom transfer radical polymerization (photo-ATRP) has emerged as a prominent technique in contemporary polymer chemistry, offering a potent means to create precisely structured materials. Well-defined catalysts are essential for controlling the growth of polymers with reproducible results; however, most photo- ATRP catalytic systems involve mixing the metal salt with the ligand. Herein we present a well-defined iron (III) based photo-ATRP catalyst bearing bidentate NHC ligand, 3-Methyl-1-phenyl-1H-3,1-benzimidazol-3-ium iodide (Pmb). The [FeBr(Pmb) 2 2 ] was successfully synthesized and fully characterized by FTIR, UV–Vis, and EPR spectroscopic studies, elemental analysis, MALDI-TOF mass spectrometry, and computational studies. [FeBr (Pmb) ] was employed as the catalyst for photo-ATRP of methyl methacrylate (MMA) under ultraviolet light irradiation (365 nm). The catalytic activity of [FeBr(Pmb) 2 ] in the photo-ATRP of MMA was evaluated under different conditions using EBPA as the initiator. The polymerizations showed robust activity, yelding in polymers with controlled molecular weights and a narrow molecular weight distribution (MWD). Remarkably, this was achieved with low catalysts loading (102.6 ppm), mainly at the molar ratio [MMA]/[EBPA]/[Fe] = 200/1/0.04. Well-defined polyMMA was synthesized and temporal control over photo-ATRP was successfully demonstrated through “on/off” experiments. For example, photo-ATRP of MMA with a molar ratio of [200/1/0.04] after 12 h at T = 25 ◦ C in bulk resulted in PMMA with a polydispersity (Ð) of 1.15 at 50 % monomer conversion.

DOI: https://doi.org/10.1016/j.jphotochem.2024.115567

Projeto BEPE/BEPE Project

Controlled Radical Photopolymerization (CRP2) and 3D printing using novel Ni(II) complexess

Abstract: Ni(II) complexes were synthesized to catalyze Controlled Radical Photopolymerization (CRP2). The proposal extended into three stages, which were completely interconnected in the development process. Initially, the attention was directed to the Ni(II) complexes bearing Schiff base and non-symmetric NHCs ligands synthesis. New Ni(II) complexes were characterized by FTIR, UV-Vis, Cyclic Voltammetry, EPR, 1H and 13C NMR techniques, elemental analysis and mass spectrometry. The second stage was dedicated to the evaluation of the photochemical properties of the nickel-NHC and Schiff bases complexes. Consequently, the high reactivity of these compounds was demonstrated through some direct laser write experiments, where high-spatial-resolution 3D patterns will be obtained. Therefore, this research paves the way for the development of new organometallic photocatalysts in CRP2 as well as their applications in 3D printing.

Nesse projeto ocorreu uma colaboração incrível com o professor Jacques Lalevée, um excelente pesquisador na área de fotopolimerização e fotoquímica. No grupo do professor Jacques houve muita troca cultural e de experiências com diferentes estudantes e pesquisadores. Além disso, a pesquisa que desenvolvi no estágio no exterior foi apresentada em congressos internacionais e em reuniões científicas do grupo. Um dos trabalhos foi premiado como melhor apresentação e poster. Vale ressaltar que um artigo foi publicado usando os complexos de Ni(II)-base de Schiff com relevantes destaques e impressão 3D. Ademais, eu pude aplicar complexos de cobre(I) como fotocatalisadores em reações de fotopolimerização e impressão 3D em colaboração com o professor Jacques Lalevée e o outro pesquisador Matteo Mauro da Universidade de Strasburgo, este artigo foi aceito para publicação.

This project involved an incredible collaboration with Professor Jacques Lalevée, an outstanding researcher in the fields of photopolymerization and photochemistry. In his research team, there was a rich exchange of cultural and scientific experiences with students and researchers from diverse backgrounds. Additionally, the research I conducted during my international internship was presented at international conferences and scientific meetings within the group. One of the studies was awarded for the best presentation and poster. Notably, an article was published on Ni(II)-Schiff base complexes, highlighting significant findings and 3D printing applications. Furthermore, I had the opportunity to apply copper(I) complexes as photocatalysts in photopolymerization reactions and 3D printing in collaboration with Professor Jacques Lalevée and researcher Matteo Mauro from the University of Strasbourg. This article has been accepted for publication.

Oral presentation in Greece

Oral presentation in Spain

Poster presentation in France

Award in France

Artigo/Article: Advancing photopolymerization and 3D printing: High-Performance NiII complexes bearing N2O2 Schiff-base ligands as photocatalysts

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 NiII complexes NiL1 and NiL2 were synthesized using N2O2 Schiff-base ligands bearing π-extended rings (naphthaldehyde (H2L1) and phenylsalicylaldehyde (H2L2) groups), respectively. These complexes were characterized by FTIR, UV–Vis and 1H 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. Three-component 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.

DOI: https://doi.org/10.1016/j.eurpolymj.2024.113279

Artigo/Article: Heteroleptic Copper(I) Complexes with Pyridine-Benzothiazole Ligands as photocatalysts for Free Radical Photopolymerization and 3D printing

Abstract

Copper(I) complexes have attracted considerable attention as efficient redox photocatalysts (PCs) in photopolymerization. In this study, two copper(I) complexes bearing a pyridine-benzothiazole ligand were thoroughly investigated as photocatalysts for the free radical photopolymerization of ethoxylated trimethylolpropane triacrylate under violet and green light irradiation. A three-component system comprising a copper complex, di-tert-butyl-diphenyl iodonium hexafluorophosphate, and ethyl dimethylaminobenzoate as additives was investigated under various conditions. The copper complexes exhibited remarkable photoinitiation capabilities, achieving high monomer conversion rates and highlighting significant structure-reactivity relationships. Based on free energy calculations and spectroscopic analyses, a mechanistic pathway was proposed. The optimal condition was successfully applied in 3D printing, producing smooth and uniform 3D structures.

DOI: https://doi.org/10.1021/acsapm.4c04066

No retorno ao Brasil em 2024, os resultados da pesquisa foram apresentados no congresso BMIC. Esse congresso foi importante para que as pessoas conhecessem a parceria que temos desenvolvido no uso de complexos da primeira série de transição da tabela periódica como promissores fotocatalisadores em reações de polimerização, assim como sua aplicação em impressão 3D.

Upon returning to Brazil in 2024, the research results were presented at the BMIC conference. This conference was important for showcasing the partnership we have developed in utilizing transition metal complexes from the first row of the periodic table as promising photocatalysts in polymerization reactions, as well as their application in 3D printing.

Article: Visible light-promoted nickel-NHC photocatalysts for free radical photopolymerization and 3D printing application

The evaluation of NiII complexes bearing bidentate N-heterocyclic carbene (NHC) ligands has shown their great potential as catalysts in various reactions. However, their luminescence properties and photocatalytic applications remain underexplored. Two novel nickel-based NHC complexes, [Ni(py-NHC)2](PF6)2 (NiC1) and [Ni(ph-NHC)2] (NiC2), were synthesized with ligands N-mesityl-N′-2-pyridylimidazolium tetrafluorophosphate and 1-mesityl-3-phenyl-1H-imidazol-3-ium tetrafluorophosphate, respectively. The complexes were thoroughly characterized using spectroscopy techniques, including FTIR, UV-Vis, 1H NMR, and fluorescence, along with elemental analysis, cyclic voltammetry, and mass spectrometry. NiC1 and NiC2 exhibited emission properties and lifetimes of 3.8 and 9.1 ns, respectively. The photocatalytic properties of NiC1 and NiC2 were investigated for initiating free radical photopolymerization of ethoxylated trimethylolpropane triacrylate under violet light. This process incorporated di-tert-butyl-diphenyl iodonium hexafluorophosphate and ethyl dimethylaminobenzoate as additives. NiC2 achieved the highest monomer conversion under air or in laminate and was effective in on–off LED irradiation. Proposed oxidative and reductive mechanisms were supported by photolysis, fluorescence quenching, and electron spin resonance data. The optimized system was applied in 3D printing, producing smooth-surfaced, high-resolution patterns.

Atualmente/Currently

Novos complexos de Ni(II) têm sido sintetizados e investigados como fotocatalisadores para fotopolimerização radicalar e catiônica. O objetivo é buscar alternativas mais sustentáveis para a obtenção de polímeros, incluindo o uso de monômeros derivados de fontes naturais. Além disso, um novo desafio será explorado: a despolimerização e fotodespolimerização. A colaboração com o Professor Jacques Lalevée continua, assim como a participação de estudantes de iniciação científica e pós-graduação sob a supervisão da Profa. Dra. Beatriz Eleutério Goi. A busca por reações sustentáveis tem crescido, uma vez que é necessário encontrar alternativas para minimizar os problemas ambientais e energéticos.

New Ni(II) complexes have been synthesized and investigated as photocatalysts for radical and cationic photopolymerization. The goal is to explore more sustainable alternatives for polymer production, including the use of monomers derived from natural sources. Additionally, a new challenge is being explored: depolymerization and photodepolymerization. The collaboration with Professor Jacques Lalevée continues, as well as the involvement of undergraduate and graduate students under the supervision of Prof. Dr. Beatriz Eleutério Goi. The demand for sustainable reactions has been increasing, as finding alternatives to reduce environmental and energy challenges is essential.

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