Robust Organometallic Gold Nanoparticles

Abstract

Robust gold−carbon nanoparticles were synthesized by the sodium borohydride reduction of the diazonium tetrachloroaurate(III) complex [C 8 F 17 -4-C 6 H 4 NN]AuCl 4 . FT-IR, 1 H NMR, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) of the ruby red gold nanoparticles indicated the absence of the diazonium nitrogen and the presence of the organic shell C 8 F 17 -4-C 6 H 4 . Temperature-dependent Xray powder diffraction (TD-XRD) measurements showed intense cubic gold nanoparticle diffraction patterns in the temperature range 300−500 °C.The effective hydrodynamic size measured by a nanoparticle track analyzer (NTA) in ethanol is 45 nm, and the average core size estimated by transmission electron microscopy (TEM) is 3.2 ± 0.2 nm. The core−shell bonding is strong and is able to withstand prolonged sonication in ethanol and acetonitrile and indefinite exposure to ambient conditions in the solid state.

Functionalization of nanomaterials with aryldiazonium salts

“…18) A single-phase synthesis of organometallic gold nanoparticles was reported in a recent communication [155]. Sodium borohydride (NaBH 4 ) reduction of [C 8 F 17 -4-C 6 H 4 N≡N]AuCl 4 produced ruby red gold-carbon nanoparticles (Fig.…”

“…26 [54], (iii) phase-transfer of tetrachloroaurate(III) to a diazonium salt solution [56], (iv) reduction of both auric and isolated diazonium salts in aqueous medium [154], and (v) direct synthesis of benzenediazonium salt bearing tetrachloroaurate(III) [155]. Other metals have also been capped with aryl layers from diazonium salts, namely platinum [56], titanium [156], palladium [157], iron [158] and vanadium [159].…”

“…However, long term stability has been a major concern. To address this critical point, the group of one of the authors of this review Ahmed Mohamed designed "gold diazonium" salts with a remarkable stability [45,46,155]. Other authors have confirmed the stability of aryldiazonium tosylate salts [149] on the top of their interesting water solubility.…”

Synthesis, Characterization, and Antimicrobial Activity of Near‐IR Photoactive Functionalized Gold Multibranched Nanoparticles

“…As NIR light is capable of penetrating deeper tissues, NPs capable of absorbing NIR light are postulated to be suitable for use as photothermal agents in vivo . However, standard thiol chemistry or non‐covalent binding of functional molecules to the AuNPs surface is not the best choice for in vivo conditions for several reasons: the increased ion strength can disrupt the non‐covalent interaction; the thiol groups from in vivo occurred peptides can substitute the functional groups on the AuNPs surface; and finally, the Au−C bonds are stronger than Au−S (the binding energy of the aryl layer on gold is higher by 14.2 kJ mol −1 than that of the thiol) …”

“…[36] However,s tandard thiol chemistry or non-covalent binding of functionalm olecules to the AuNPs surfacei sn ot the best choice for in vivo conditions for several reasons:t he increased ion strengthc an disrupt the non-covalent interaction;t he thiol groupsf rom in vivo occurred peptides can substitute the functionalg roups on the AuNPs surface; andf inally,t he AuÀCb onds are stronger than AuÀS( the binding energy of the aryl layer on gold is higherb y 14.2 kJ mol À1 than that of the thiol). [37,38] To the best of our knowledge,m ost work in the field of gold nanoparticles functionalizationh as used the thiol approach. However,t emperature increases or laser illumination associated with the use of AuNPs for phototherapy can disrupt the thiol bonds,l eading to the loss of nanoparticle activity.…”