Synthesis and catalytic applications of metal complexes supported by indole‐functionalized mesoionic 1,2,3‐triazolylidenes

Abstract

We report the synthesis and full characterization of a novel series of indole-derived triazolium salts and their corresponding triazolylidene gold, palladium, rhodium and iridium complexes. All new compounds were fully characterized by means of 1H and 13C NMR spectroscopy, elemental analyses and in the case of triazoliums 1 and 2 and complexes 3, 4 and 9, by single crystal X-ray diffraction. Gold complexes demonstrated a good catalytic performance in the hydrohydrazination of terminal alkynes producing a series of substituted hydrazones in good yields under mild reaction conditions. Additionally, the iridium complex (9) performed well in the catalytic transfer hydrogenation of ketones and aldehydes using isopropanol as hydrogen source.