Volume 26, Issue 14 p. 3157-3165
Full Paper

Mild Homogeneous Synthesis of Gold Nanoparticles through the Epoxide Route: Kinetics, Mechanisms, and Related One-Pot Composites

Dr. Víctor Oestreicher

Corresponding Author

Dr. Víctor Oestreicher

Instituto de Nanosistemas, UNSAM, CONICET, 25 de mayo 1021, San Martín, 1650 Buenos Aires Argentina

Gerencia Química & Instituto de Nanociencia y Nanotecnología, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, CONICET, Av. Gral. Paz 1499, San Martín, B1650KNA Buenos Aires Argentina

Current address: Instituto de Ciencia Molecular (ICMol), Universidad de Valencia, Catedrático José Betrán 2, 46980 Paterna, Valencia, Spain

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Dr. Cristián Huck-Iriart

Dr. Cristián Huck-Iriart

Escuela de Ciencia y Tecnología, UNSAM, CONICET, 25 de mayo 1650, San Martín, 1650, Buenos Aires Argentina

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Prof. Dr. Galo Soler-Illia

Prof. Dr. Galo Soler-Illia

Instituto de Nanosistemas, UNSAM, CONICET, 25 de mayo 1021, San Martín, 1650 Buenos Aires Argentina

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Dr. Paula C. Angelomé

Dr. Paula C. Angelomé

Gerencia Química & Instituto de Nanociencia y Nanotecnología, Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, CONICET, Av. Gral. Paz 1499, San Martín, B1650KNA Buenos Aires Argentina

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Prof. Dr. Matías Jobbágy

Corresponding Author

Prof. Dr. Matías Jobbágy

Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. II, Buenos Aires, C1428EHA Argentina

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First published: 09 January 2020
Citations: 7

Dedicated to Professor Enrique San Román

Graphical Abstract

Homogeneous alkalinization leads to the quantitative formation of gold nanoparticles at room temperature by means of epoxide ring-opening. The new methodology takes advantage of the kinetically controlled generation of OH in the reaction medium; under alkaline conditions spheroidal Au nanoparticles are formed. The required stabilizing agents affect the mechanism of growth and kinetics, as demonstrated by spectroscopic measurements.

Abstract

A new one-pot homogeneous methodology at room temperature to obtain Au nanoparticles (AuNP) on the basis of the epoxide route is presented. The proposed method takes advantage of the homogenous generation of OH moieties driven by epoxide ring-opening, mediated by chloride nucleophilic attack. Once reached alkaline conditions, the reducing medium allows the quantitative formation of AuNP under well-defined kinetic control. A stabilizing agent, such as polyvinylpyrrolidone (PVP) or cetyltrimethylammonium chloride (CTAC), is required to maintain the AuNP stable. Meanwhile their presence dramatically affects the reduction kinetics and pathway, as demonstrated by the evolution of the UV/Vis spectra, small-angle X-ray scattering (SAXS) patterns, and pH value along the reaction. In the presence of PVP nanogold spheroids are obtained following a similar reduction mechanism as that observed for control experiments in the absence of PVP. However, if CTAC is employed a stable complex with AuIII is formed, leading to a different reaction pathway and resulting in ellipsoidal-like shaped AuNP. Moreover, the proposed methodology allows stabilize the growing AuNP, by coupling their formation with nonalkoxidic sol–gel reactions, leading to nanocomposite gels with embedded metallic nanoparticles. The epoxide route thus offers a versatile scenario for the one-pot preparation of new metal nanoparticles–inorganic/hybrid matrices nanocomposites with valuable optical properties.

Conflict of interest

The authors declare no conflict of interest.