Preparation and evaluation of 2-azinyl-2H-benzotriazoles as bidentate ligands: Synthesis and characterization of [2-(2-pyridynyl)-2H-benzotriazole] (bpy)₂Ru²⁺

Five 2-azinyl-2H-benzotriazoles (azinyl = 2-pyridinyl, 2-pyrazinyl, 2-pyrimidinyl, 6-methoxy-3-pyridazinyl, 5-methyl-2-pyridinyl were prepared and characterized as bidentate ligands. The electronic structure of these and related heterocycles was investigated spectroscopically and computationally (TD-DFT). They were tested at the B3LYP/6-31++G(d, p)//B3LYP/6-31G(d, p) level of theory as ligands for MgH₂, which permitted the elucidation of trends in complex formation, its geometry as a function of the ring structure, and the number and position of the nitrogen atoms in the azine ring. A Ru ²⁺ complex 7a-Ru with 2-pyridinyl-2H-benzotriazole (7a) and two bpy ligands was prepared and characterized structurally, spectroscopically and electrochemically. The results were compared to those for similar complexes and discussed in the context of computational results for MgH₂ complexes.