Terpyridine Zn(ii), Ru(iii) and Ir(iii) complexes as new asymmetric chromophores for nonlinear optics: first evidence for a shift from positive to negative value of the quadratic hyperpolarizability of a ligand carrying an electron donor substituent upon coordination to different metal centres

Abstract

The synthesis of 4′-(C₆H₄-p-NBu₂)-2,2′:6′,2″-terpyridine and the strongly enhanced second-order NLO response of its Zn(II), Ru(III) and Ir(III) complexes are reported, evidencing for the first time a shift from positive to negative value of the ligand quadratic hyperpolarizability by varying the nature of the metal centre.