From Ligand to Phosphor: Rapid, Machine-Assisted Synthesis of Substituted Iridium(III) Pyrazolate Complexes with Tuneable Luminescence

A first‐generation machine‐assisted approach towards the preparation of hybrid ligand/metal materials has been developed. A comparison of synthetic approaches demonstrates that incorporation of both flow chemistry and microwave heating can be successfully applied to the rapid synthesis of a range of new phenyl‐1H‐pyrazoles (ppz) substituted with electron‐withdrawing groups (−F, −CF₃, −OCF₃, and −SF₅). These, in turn, can be translated into heteroleptic complexes, [Ir(ppz)₂(bipy)]BF₄ (bipy=2,2′‐bipyridine). Microwave‐assisted synthesis for the IrIII complexes allows isolation of spectroscopically pure species in less than 1 h of reaction time starting from IrCl₃. All of the new complexes have been characterised photophysically (including nanosecond time‐resolved transient absorption spectroscopy), electrochemically, and by TD‐DFT studies. The complexes exhibit ligand‐dependent, tuneable, green‐yellow luminescence (500–560 nm), with quantum yields in the range 5–15 %.