The remarkable resilience of N-heterocyclic carbene (NHC) gold bonds has quickly made NHCs the ligand of choice when functionalizing gold surfaces.D espite rapid progress using deposition from free or CO 2 -protected NHCs, synthetic challenges hinder the functionalization of NHC surfaces with protic functional groups,s uch as alcohols and amines,p articularly on larger nanoparticles.H ere,w es ynthe-sizeN HC-functionalized gold surfaces from gold(I) NHC complexes and aqueous nanoparticles without the need for additional reagents,e nabling otherwise difficult functional groups to be appended to the carbene.T he resilience of the NHC À Au bond allows for multi-step post-synthetic modification. Beginning with the nitro-NHC,w ef orm an amine-NHC terminated surface,w hichf urther undergoes amide coupling with carboxylic acids.T he simplicity of this approach, its compatibility with aqueous nanoparticle solutions,a nd its ability to yield protic functionality,g reatly expands the potential of NHC-functionalized noble metal surfaces.

The remarkable resilience of N-heterocyclic carbene (NHC) gold bonds has quickly made NHCs the ligand of choice when functionalizing gold surfaces.D espite rapid progress using deposition from free or CO 2 -protected NHCs, synthetic challenges hinder the functionalization of NHC surfaces with protic functional groups,s uch as alcohols and amines,p articularly on larger nanoparticles.H ere,w es ynthe-sizeN HC-functionalized gold surfaces from gold(I) NHC complexes and aqueous nanoparticles without the need for additional reagents,e nabling otherwise difficult functional groups to be appended to the carbene.T he resilience of the NHC À Au bond allows for multi-step post-synthetic modification. Beginning with the nitro-NHC,w ef orm an amine-NHC terminated surface,w hichf urther undergoes amide coupling with carboxylic acids.T he simplicity of this approach, its compatibility with aqueous nanoparticle solutions,a nd its ability to yield protic functionality,g reatly expands the potential of NHC-functionalized noble metal surfaces.