The Combination of 4‐Hydroxythiazoles with Azaheterocycles: Efficient Bidentate Ligands for Novel Ruthenium Complexes

Herein the syntheses of three novel ligands, in which an azaheterocycle is connected with a thiazole subunit: 4‐methoxy‐5‐methyl‐2‐pyridine‐2‐yl‐1,3‐thiazole (1), 4‐methoxy‐5‐methyl‐2‐pyrimidine‐2‐yl‐1,3‐thiazole (2) and 4‐methoxy‐5‐phenyl‐2‐pyridine‐2‐yl‐1,3‐thiazole (3) are reported. Because these ligands are cyclic versions of 1,4‐diazadienes, they offer good prerequisites for the synthesis of metal complexes and were employed as chelating ligands. Three novel heteroleptic cationic complexes of the type Ru(bpy)2(L), with bpy = 2,2′‐bipyridine were successfully synthesised. The RuII complexes as well as the ligands were characterised by means of mass spectrometry, NMR, UV/Vis and IR spectroscopy and elemental analysis. Furthermore, an X‐ray structure of Ru(bpy)22(PF6), as far as we know the first example where a thiazole is directly connected to a RuII core, is presented in this paper.