Syntheses and properties of new metal–carbon bonded heteroleptic complexes of ruthenium(II) containing terpyridine coligand

摘要

Reactions of 2-(arylazo)aniline, HL [H represents the dissociable protons upon orthometallation and HL is p-RC_6H_4N =NC_6H_4–NH_2; R = H for HL~1; CH_3 for HL~2 and Cl for HL_3] with Ru(R_1-tpy)Cl_3 (where R1-tpy is 40-(R_1)-2,20,60 0,20 0-terpyridine and R1 = H or 4-N,N-dimethylaminophenyl or 4-methylphenyl) afford a group of complexes of type [Ru(L)(R_1-tpy)]·ClO_4 each of which contains C,N,N coordinated L~- as a tridentate ligand along with a terpyridine. Structure of one such complex has been determined by X-ray crystallography. All the Ru(II) complexes are diamagnetic, display characteristic ~1H NMR signals and intense dπ(Ru~II)→π~·(tpy) MLCT transitions in the visible region. Cyclic voltammetric studies on [Ru(L)(R_1-tpy)]- ClO_4 complexes show Ru(II)–Ru(III) oxidation within 0.63–0.67 V versus SCE.