Ligand motifs containing 1,2,3-triazole subunits have become increasingly prevalent due to their ease of preparation as allowed by Sharpless-Meldal click methods. A common example is the 2,6-bis(1-substituted-1,2,3-triazol-4-yl)pyridine ligand, which has been shown to coordinate a variety of transition metals in a neutral tridentate manner. 1,2,3-Triazole-containing ligands able to coordinate metals as anionic ligands are much less prevalent. Anionic ligands can display organometallic properties unique to analogous neutral ligands, as well as preclude the requirement of outer sphere counterions. This study developed two previously unreported 1,2,3-triazole ligand motifs displaying the ability to coordinate transition metals in an anionic tridentate manner: 2-(1H-tetrazol-5-yl)-6-(1-substituted-1,2,3-triazol-4-yl)pyridine and 6-(1-substituted-1,2,3-triazol-4-yl)-2-carboxypyridine. Analogs of each of these ligand motifs, where substitution at the 1-triazolyl position was varied between electron-rich and electron-poor functionality, were each prepared in three steps from commercially available starting materials in good overall yields. These ligands showed the ability to form stable 2:1 ligand:metal Ru(II) complexes. Details of the preparation of these ligands and metal complexes, as well as a summary of how peripheral substituents on the triazole ring impact the optoelectronic properties of the Ru(II) complexes, will be presented.

1,2,3-Triazole-containing anionic tridentate chelators

248th National Meeting (2014)

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