Theoretical Study Of The Property-Structure Relationship Of A Series Of Ferrocenyl Second-Order Nonlinear Optical Complexes

Among various kinds of transition metal coordinates, Ferrocenyl-containing organometallic complexes possess rich opt-electric properties. Such complexes have been drawing much experimental and theoretical research attention in various field including nonlinear optics. Recently, a great amount of ferrocene derivatives have been synthesized. We studied the structural, absorption spectral and the second-order nonlinearitis properties of a series of ferrocene derivatives. These complexes we studied possess D-П-A structural property. Results obtained by DFT and TDDFT and SOS method showed that changing the number of the bridging ethyldiene can change the second-order nonlinearities of different complex with the same donor and acceptor groups. For the same donor and acceptor groups, the introduction of an conjugated substituent, the second-order nonlinearities increased. Moreover, with the conjugation extent and the electron-withdrawing strength increased, the increase of the second-order nonlinearities were magnified. Result on the absorption spectra and detail analysis of the molecular orbital properties showed that, in D-П-A structure characterized ferrocenyl complexes(a, b, d) without any substituents, electrons were excited from the ferrocenyl moiety to the p-nitrophenyl groups, the delcolization of the high-level orbital to which the ecletron was excited can lead to red shift of the max absorption wavelength. While in the case with substituents the excitation that most contributed to max-wavelength absorption was not from the ferrocenyl groups, such excitations localized between the substituents and the p-nitrophenyl moiety. So it is obvious substituent of large conjugation will lead to red shift of the corresponding absorption wavelength.