Ruthenium(II) P-Cymene Complexes Bearing 2‑(1,2,4‑triazol‑3‑yl)pyridines: Linkage Isomerism and Related NMR/DFT Studies

A series of ruthenium(II) p-cymene complexes bearing 2‑(1,2,4‑triazol‑3‑yl)pyridines was obtained. A simple and efficient 1H NMR spectroscopic criterion for determining coordination mode of the 2‑(1,2,4‑triazol‑3‑yl)pyridines as ligands in the complexes is described. The validity of the criterion is corroborated by DFT calculations using B3LYP functional and mixed LANL2DZ/6-31**G basis set. Also, the influence of the size of the substituent in 5-position of the triazole ring on linkage isomers' ratio is discussed.