title: Preparation of Aun quantum clusters with catalytic activity in β-cyclodextrin polyurethane nanosponges.
abstract: Here we report the use of β-cyclodextrin polyurethane nanosponges cross-linked with 1,6-hexamethylene diisocyanate as a template for the preparation of Aun quantum clusters, by the core-etching of glutathione-capped Au nanoparticles. The study of temporal evolution of the core-etching process using different Au concentrations indicated that formation of Aun clusters embedded in the nanosponge is favored by the use of lower Au concentrations, since it began at shorter times and lead to higher cluster loading. An estimation of the number of Au atoms based on the maximum photoluminescence wavelength suggested that, depending on the Au concentration and the core etching time, clusters with 11-15 atoms were formed. After excluding the possibility of an inclusion complex formation, evaluation of the catalytic activity of nanosponge-loaded Aun clusters toward the reduction of 4-nitrophenol has shown that the reaction is catalyzed by the Aun clusters with no induction time, following the Langmuir-Hinshelwood kinetic model.
authors.affiliation: Programa de Pós-graduação em Química, Av. Marechal Rondon s/n, Cidade Universitária "Prof. José Aloísio de Campos", CEP 491000-000 São Cristóvão, SE, Brazil.
authors.forename: Diego Andrade
authors.initials: DA
authors.lastname: Vasconcelos
authors.affiliation: Programa de Pós-graduação em Química, Av. Marechal Rondon s/n, Cidade Universitária "Prof. José Aloísio de Campos", CEP 491000-000 São Cristóvão, SE, Brazil; CARBOPOL, Laboratório de Síntese de Polímeros Derivados de Carboidratos, Faculdade Pio Décimo, Av. Presidente Tancredo Neves, 5655, Jabotiana, Aracaju, SE 49095000, Brazil.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Kubota
authors.affiliation: Programa da Pós-graduação em Ciência e Engenharia de Materiais, Av. Marechal Rondon s/n, Cidade Universitária "Prof. José Aloísio de Campos", CEP 491000-000 São Cristóvão, SE, Brazil.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Santos
authors.affiliation: CARBOPOL, Laboratório de Síntese de Polímeros Derivados de Carboidratos, Faculdade Pio Décimo, Av. Presidente Tancredo Neves, 5655, Jabotiana, Aracaju, SE 49095000, Brazil.
authors.forename: Marcia V G
authors.initials: MV
authors.lastname: Araujo
authors.affiliation: Programa de Pós-graduação em Química, Av. Marechal Rondon s/n, Cidade Universitária "Prof. José Aloísio de Campos", CEP 491000-000 São Cristóvão, SE, Brazil; Programa da Pós-graduação em Ciência e Engenharia de Materiais, Av. Marechal Rondon s/n, Cidade Universitária "Prof. José Aloísio de Campos", CEP 491000-000 São Cristóvão, SE, Brazil.
authors.forename: Zaine
authors.initials: Z
authors.lastname: Teixeira
authors.affiliation: Programa de Pós-graduação em Química, Av. Marechal Rondon s/n, Cidade Universitária "Prof. José Aloísio de Campos", CEP 491000-000 São Cristóvão, SE, Brazil; Programa da Pós-graduação em Ciência e Engenharia de Materiais, Av. Marechal Rondon s/n, Cidade Universitária "Prof. José Aloísio de Campos", CEP 491000-000 São Cristóvão, SE, Brazil. Electronic address: gimenez@ufs.br.
authors.forename: Iara F
authors.initials: IF
authors.lastname: Gimenez
mesh_terms: D002384:Catalysis; D005978:Glutathione / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D017953:Isocyanates / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009596:Nitrophenols / Q000737:chemistry; D010084:Oxidation-Reduction; D011140:Polyurethanes / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D017953:Isocyanates; D009596:Nitrophenols; D011140:Polyurethanes; D047392:beta-Cyclodextrins; C015262:1,6-hexamethylene diisocyanate; D006046:Gold; D005978:Glutathione; C031215:betadex; C024836:4-nitrophenol
keywords: Au(n) clusters; Cyclodextrin polyurethane; Magic clusters; Nanosponge; Quantum clusters