Gold nanoparticles functionalization with 1-(2-furoyl)-3-phenylthiourea

Understanding the impact of functionalizing gold nanoparticles with thiourea derivatives is essential for optimizing their physicochemical properties and developing platforms based on the integration of these systems for specific applications. Gold nanoparticles functionalization with acylthioureas is a novel approach due to the lack of prior literature on this class of compounds. In this work, gold nanoparticles were obtained by the Turkevich method using a gold precursor/reducing agent ratio of 1/10.5. The nanoparticles were characterized using UV-Vis spectroscopy, electrophoretic light scattering, and transmission electron microscopy. The surface plasmon resonance band of the nanoparticles was used to evaluate the impact of their interaction with thiourea and 1-(2-furoyl)-3-phenylthiourea in aqueous media, and the electrochemical response of the thiourea derivative was previously evaluated on an Au(111) electrode. Finally, solid-phase diffuse reflectance spectra of the samples involved in this system were obtained as direct evidence of the functionalization of the gold nanoparticles. This multi-technique characterization provided robust evidence of successful surface modification and colloidal stability. Crucially, this study provides the first evidence of a key advantage: 1-(2-furoyl)-3-phenylthiourea effectively modifies the nanoparticle surface without inducing significant aggregation, a common limitation with simple thiourea. Additionally, an insightful discussion on tautomerism and substituent effects in explaining the differences in aggregation behavior between both compounds is addressed.