Synthesis, Characterization, and Electronic Properties of Porphyrins Conjugated with N‑Heterocyclic Carbene (NHC)–Gold(I) Complexes

Porphyrins fused to peripheral N-heterocyclic carbenes (NHC) across two neighboring β,β-pyrrolic positions were used for the synthesis of different mono- and bis-carbenic gold­(I) complexes. These studies also revealed how it is possible to modulate the reactivity of the peripheral NHC by deprotonating the inner NH groups of the fused free base porphyrin core. All complexes were fully characterized and displayed high stability, allowing the formation of mono-carbenic and also stable homoleptic and heteroleptic bis-carbenic Au­(I) complexes. Optical and electrochemical properties of bis-carbenic Au­(I) revealed no or weak electronic communication between the porphyrins, which behave as two independent groups.