Luminescent Platinum(II) Complexes with a Tridentate Caffeine‐Based NHC‐Pincer Ligand : Synthesis, Electrochemistry and Photophysics

A strategy of “greening up” Pt(II) luminophores is presented. For this purpose, caffeine, as a renewable alkaloid and precursor for an N ‐heterocyclic carbene (NHC), is incorporated into a tridentate, pincer‐type ligand framework. A series of luminescent Pt(II) complexes, containing the tridentate bis ‐NHC ligand and an arylacetylide ligand is reported. The complexes’ electrochemistry and photophysics strongly depend on the electronic nature of the substituent on arylacetylide ligand. The use of bio‐derived ligands represents one important approach to make emitters or sensitizers eco‐friendlier by coming back to cheap, abundant and non‐harmful staring materials for their synthesis.