Synthesis of <i>N</i> ‐Heterocyclic Carbene Au(I)‐Aryl Complexes Through Mild Base‐Assisted Transmetallation of Arylboronic Acids: Scope and Limitations

A resurgence of research surrounding Au(I)-Aryl complexes has led to sustainable methods toward their synthesis, as well as to the expansion of their scope and applications in catalysis, biology, and materials chemistry. The availability of mild synthetic methodologies has facilitated the design and development of Au(I)-Aryl architectures suitable for specific photonic applications, such as Thermally Activated Delayed Fluorescence (TADF) and Room Temperature Phosphorescence (RTP) emitters. The development and application of reliable synthetic methods have increased, yet several synthetic aspects remain to be uncovered. Herein, the synthesis of N-heterocyclic carbene (NHC) Au(I)-Aryl complexes through mild, base-assisted transmetallation of arylboronic acids is further explored, targeting Au(I)-Aryl structures incorporating polyaromatic and triarylborane frameworks, and structural features of relevance to organometallic synthesis, supramolecular chemistry, and luminescence. In addition to the utilization of K₂CO₃ as the mild, cost-effective base of choice, we introduce the use of aqueous ammonia as a novel tool that facilitates transmetallation to gold. The purpose of additional exploration is to discover limitations of the synthetic methods, as well as inherent flaws regarding the design of [Au(NHC)(Ar)] (Ar = Aryl) complexes. Previously undiscovered synthetic limitations are disclosed, along with practical alternatives.