Details

Autor(en) / Beteiligte

• Young, Adam J.
• Eisen, Constantin
• Rubio, Guilherme M.D.M.
• Chin, Jia Min
• Reithofer, Michael R.

Titel

pH responsive histidin-2-ylidene stabilized gold nanoparticles

Ist Teil von

• Journal of inorganic biochemistry, 2019-10, Vol.199, p.110707-110707, Article 110707

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2019

Quelle

Access via ScienceDirect (Elsevier)

Beschreibungen/Notizen

• N-Heterocyclic carbene-stabilized metal nanoparticles have drawn much attention over the last decade due their strong carbon metal bond. Although several reports show increased stability of such N-heterocyclic carbene-stabilized metal nanoparticles, only limited examples of water-soluble N-heterocyclic carbene stabilized metal nanoparticles are known to date. However, water dispersibility and stability in biologically relevant solvents would be a prerequisite for any biological applications. Drawing from the natural amino acid chiral pool, L-histidine was utilized for preparing chiral NHC ligands in the synthesis of water soluble NHC-stabilized gold nanoparticles. For this purpose, N-acetyl-L-histidine ethyl ester was converted into its imidazolium salt either using methyl iodide or 2-iodopropane as alkylation agent. Subsequent reaction of the imidazolium salt with [Au(SMe2)Cl] yielded the corresponding organometallic gold chloride complex. Histidine-2-ylidene stabilized gold nanoparticles were first generated in organic solvents; the histidine derived capping ligand bore ethyl ester moieties which were saponified, affording water soluble pH-responsive NHC-stabilized gold nanoparticles. These gold nanoparticles show remarkable stability in aqueous solutions, with gold nanoparticle solutions remaining stable after months of storage. Novel water soluble, N-heterocyclic carbene stabilized gold nanoparticles were prepared by utilizing new histidine-2-ylidene derived ligands bearing a carboxylic moiety. Of these, the 1,3-dimethyl-N-acetyl-histidin-2-ylidene stabilized gold nanoparticles displayed pH responsive behaviour and high stability in various biologically relevant solutions. [Display omitted] •Novel water soluble histidin-2-ylidene stabilized gold nanoparticles prepared.•High stability of gold nanoparticles in various biologically relevant solutions presented•Reversible pH responsive behaviour of gold nanoparticles achieved through use of a carboxylic acid moiety•Sterically bulky groups on imidazolium Ns may decrease gold nanoparticle stability.