Limits in the second-order response of [M(H2imXdt) (H2imYdt)] neutral complexes (M=Ni, Pd, Pt; H2imXdt=monoanion of imidazolidine-2-chalcogenone-4,5-dithione; X=O, S, Se; Y=O, S, Se; X≠Y): a pure theoretical study based on TD-DFT approach and ZORA formalism

摘要: Abstract Static and dynamic first hyperpolarizabilities, associated with an external electric perturbation in the dipole approximation, have been calculated for neutral [M(H2imXdt)(H2imYdt)] (M=Ni, Pd, Pt; H2imXdt=monoanion of imidazolidine-2-chalcogenone-4,5-dithione; X=O, S, Se; Y=O, X≠Y) model complexes within TD-DFT approach. These never synthesized, but they are useful studying NLO activity skeleton centrosymmetric [M(RR′timdt)2], synthesized characterized, removing inversion center without extensive change to original molecule. The simple two-state did not allow explain our results, suggesting importance other excited states on second order response. Furthermore ZORA (zero regular approximation) results show increase beta tensors respect non-relativistic ones, which is roughly proportional atomic number coordinated metal. findings may indicate that transitions strongly involving metal relevant Although studied a large hyperpolarizability, particular Pt- (the [Pt(H2imOdt)(H2imSdt)] complex shows β vec (SHG) =34.8×10 −30  esu at 0.50 eV), it unable compete organic materials extensively used non-linear optical applications. On hand, noteworthy we pseudo-centrosymmetric chromophores. Their response expected be only starting point this study suggestion achieving better by modifying atoms found involved related