Metalloorganic compounds for nonlinear optics: Molecular hyperpolarizabilities of M(diimine)(dithiolate) complexes (M=Pt, Pd, Ni)

A series of mixed-ligand transition-metal diimine dithiolate complexes have been prepared, and their nonlinear optical properties have been investigated. Molecular hyperpolarizabilities have been obtained from electric field induced second harmonic generation experiments at 1.9 mu m and range in magnitude from 0 to -39 x 10(-30) esu. Variation in molecular design of the complexes, through changes in the metal ion and diimine and dithiolate ligands, can be used to affect changes in the charge-transfer-to-diimine absorption band frequency and oscillator strength. Correlation between the optical charge-transfer transition and the nonlinear optical properties appears to agree with the two-state model.