Theoretical investigation of second-order nonlinear optical response—Hexamolybdate as a superior donor over metal carbonyl complexes in the D-π-A model

摘要

Density functional theory (DFT) calculations were carried out to investigate the nonlinear optical (NLO) response for the donor-conjugated bridge-accepter (D-π-A) model of p-nitroaniline (PNA)- hexamolybdate derivatives and PNA-metal-carbonyl complexes. The bond length alternation (BLA) values decrease with lengthening of the π-conjugated bridge, especially for PNA-hexamolybdate derivatives, which dramatically enhances the NLO response. In addition, the introduction of Mo≡ N in PNA-hexamolybdate derivatives is expected to provide a better electron transition channel, consequently generating lower BLA values and an outstanding NLO response compared with PNA-metal-carbonyl complexes. It is shown that the hexamolybdate acts as an electron donor when incorporating metal-carbonyl complexes into one molecule. All these behaviors reflect the superiority of hexamolybdate as a donor moiety in the D-π-A model for the design of potential NLO materials.