Bis(heteroaryl)amino‐Substituted Phenanthrolines and Their Ru(II) Complexes for the Synthesis of Dinuclear Bimetallic Complexes

The efficient synthesis of ditopic N ‐ligands via Pd‐catalyzed N , N ‐diarylation of 5‐amino‐1,10‐phenanthroline with various 2‐halogenosubstituted heteroarenes is reported. A series of 1,10‐phenanthroline ligands containing dipyridylamine (dpa) or its analog at position 5 as an additional chelating site was obtained. Photoactive mononuclear Ru(II) and Ir(III) complexes of these ligands were prepared and characterized. X‐ray diffraction and NMR spectroscopy showed that the metal in these complexes is coordinated only to the phenanthroline moiety. The chelating substituent was found not to have any significant effect on the photophysical properties of the Ru(II) center. Three Ni(II) complexes with dpa ligands, including the binuclear complexes [(bpy) 2 Ru( L )NiCl 2 ](PF 6 ) 2 ( L = bis(pyridin‐2‐yl)amino‐1,10‐phenanthroline), were prepared and characterized. It has been shown that these bridging ligands allow to adjust the optical and electrochemical properties of Ni(II) and Ru(II) metal centers independently, which makes them perspective for systematic modulating the Ni‐centred reduction potential, while the properties of the Ru‐center remain largely unaffected.