Synthesis of Novel Periodic Mesoporous Organosilicas Containing 1,4,5,8-Naphthalenediimides within the Pore Walls and Their Reduction To Generate Wall-Embedded Free Radicals

Author(s)

Castanheira, Bruna ^[1] ; Triboni, Eduardo Resende ^[2] ; Andrade, Luana dos Santos ^[3] ; Trindade, Fabiane de Jesus ^[1] ; Otubo, Larissa ^[4] ; Silva Costa Teixeira, Antonio Carlos ^[1] ; Politi, Mario Jose ^[5] ; de Queiroz, Thiago Branquinho ^[6] ; Brochsztain, Sergio ^[3]

Affiliation

^[1] Univ Sao Paulo, Dept Engn Quim, BR-05508070 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Escola Engn Lorena, BR-05508070 Sao Paulo - Brazil

^[3] Univ Fed ABC, Ctr Engn Modelagem & Ciencias Sociais Aplicadas, Ave Estados, BR-09210170 Santo Andre - Brazil

^[4] Inst Pesquisas Energet & Nucl, BR-05508000 Sao Paulo - Brazil

^[5] Univ Sao Paulo, Inst Quim, BR-05508070 Sao Paulo - Brazil

^[6] Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210580 Santo Andre - Brazil

• Document type: Journal article
• Source: Langmuir; v. 34, n. 28, p. 8195-8204, JUL 17 2018.
• Web of Science Citations: 1

Abstract

Novel periodic mesoporous organosilicas (PMOs) containing 1,4,5,8-Naphthalenediimide (NDI) chromophores as an integral part of the pore walls were synthesized in acidic conditions, in the presence of inorganic tetraethyl orthosilicate, using triblock copolymer surfactant Pluronic P-123 as a template. The NDI precursor, the bridged silsesquioxane N,N'-bis (3-triethoxysilylpropyl)- 1,4,5,8-naphthalenediimide, was synthesized by reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride with excess 3-aminopropyltriethoxysilane. A series of samples containing up to 19% (weight %) of NDI were prepared (the materials were labeled PMONDIs). C-13 and Si-29 solid-state nuclear magnetic resonance revealed that the NDI moiety was intact in the PMONDIs and efficiently grafted to the silica network. Samples with up to 16% NDI load presented an ordered two-dimensional-hexagonal mesoscopic structure, according to small-angle X-ray scattering, transmission electron microscopy, and nitrogen adsorption isotherms. Fluorescence spectra of the PMONDIs showed excimer formation upon excitation, suggesting high flexibility of the organic moieties. Reduction of PMONDIs with aqueous sodium dithionite led to the formation of wall-embedded NDI anion radicals, as observed by the appearance of new visible/near-infrared absorption bands. The PMONDIs were also shown to be efficient photocatalysts in the degradation of sulfadiazine, an antibiotic selected here as a model pollutant, which is usually present in water bodies and wastewater. (AU)

• FAPESP's process: 17/13839-0 - Organic and inorganic systems for obtaining of meso and nanostructures
• Grantee: Eduardo Rezende Triboni
• Support Opportunities: Regular Research Grants
• FAPESP's process: 15/06064-6 - Functional organic molecules and inorganic oxides for the development of new materials
• Grantee: Eduardo Rezende Triboni
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/05496-2 - Synthesis and characterization of periodic mesoporous organosilicas containing aromatic imides for applications in the energy sector
• Grantee: Sergio Brochsztain
• Support Opportunities: Regular Research Grants