Synthesis of Ag^I and Au^I Complexes from Tetra(thiophene‐NHC)‐Substituted Ethylene and Their Tunable Fluorescence Properties

Abstract Dinuclear silver(I) and gold(I) complexes have been prepared from (NHC‐thiophene)‐substituted ethylene (NHC = N‐heterocyclic carbene). Both the 1,2,3,4‐tetrathienylethene (TTE)‐bridged tetrakisazolium salts (H₄‐L1(PF₆)₄ and H₄‐L2(PF₆)₄) and the 2,2′‐(diphenylethene‐1,1‐diyl)dithiophene (DPDT)‐bridged bisimidazolium ligand precursors H₄‐L3(PF₆)₂ have been prepared and are treated with Ag₂O to give dinuclear tetracarbene complexes [Ag₂L](PF₆)₂ (L = L1, L2) and [Ag₂(L3)₂](PF₆)₂, respectively. The silver(I) complexes undergo a transmetalation reaction with [AuCl(THT)] (THT = tetrahydrothiophene) to furnish gold(I) NHC complexes with retention of the original structures. All complexes have been characterized by multi‐nuclear magnetic resonance (NMR) and high‐resolution electrospray ionization (HR‐ESI) mass spectrometry, and single‐crystal X‐ray diffraction analysis. The thiophene‐containing NHC complexes exhibit aggregation‐induced emission behavior in acetonitrile/water solutions and temperature‐dependent fluorescence properties.