Tuning the Dipolar Second-Order Nonlinear Optical Properties of Cyclometalated Platinum(II) Complexes with tridentate N^C^N Binding Ligands

Appropriate functionalization of the cyclometalated ligand, L, and the choice of the ancillary ligand, X, allows the dipolar second-order nonlinear optical response of luminescent [PtLX] complexes - in which L is an N^C^N-coordinated 1,3-di(2-pyridyl)benzene ligand and X is a monodentate halide or acetylide ligand - to be controlled. The complementary use of electric-field-induced second-harmonic (EFISH) generation and harmonic light scattering (HLS) measurements demonstrates how the quadratic hyperpolarizability of this appealing family of multifunctional chromophores, characterized by a good transparency throughout much of the visible region, is dominated by an octupolar contribution. Minding our L and X: Appropriate functionalization of the cyclometalated 1,3-di(2-pyridyl)benzene ligand, L, and the choice of the ancillary X ligand allow the dipolar second-order nonlinear optical response of [PtLX] complexes to be controlled (see figure; MLCT=metal-to-ligand charge transfer, ILCT=Intraligand charge transfer). Copyright