First theoretical study of linear and nonlinear optical properties of diphenyl ferrocenyl butene derivatives

In this work, structure, linear and nonlinear optical (NLO) properties, as well structure–property relationships of fourteen diphenyl ferrocenyl butene compounds (DFB compounds 1–7 (E and Z isomers) have been investigated by ab initio methods and density functional theory (DFT) to evaluate the effects of the basis sets, functionals and electron correlation at the MP2 level. For the linear optical properties, we have been interested on the mean polarizability 〈α〉 and the polarizability anisotropy Δα. For the NLO properties, electric field-induced second harmonic generation (EFISHG) β//(−2ω;ω,ω) and hyper-Rayleigh scattering (HRS) βHRS(−2ω;ω,ω) were investigated. Close structures have been obtained with some DFT functionals for compound 2. NLO calculations reveal that compounds 1 and 2 for both E and Z isomers are a remarkably large βHRS. The results reached from the traditional functionals are in good accordance with those obtained by the corrected functionals. Inverse relationships between the gaps of HOMO–LUMO orbitals and first hyperpolarizabilities have been obtained. Using strong acceptor groups, the results will provide into the electronic properties of this important class of compounds with a promising future.