OEEF-Driven Intramolecular Self-Redox of Superalkali Rb₃BeB₆Be′Rb′₃: A High-Performance Candidate for NLO Molecular Switch

To provide a novel intramolecular self-redox switch, a boron-based sandwich-like complex Rb3BeB6Be′Rb′3 is achieved by using theoretical computations. An applicable oriented external electric field (OEEF) can result in the occurrence of intramolecular self-redox (IMSR) with a long-range electron transfer from tetrahedral Be′Rb′3 to Rb3Be and subsequently [Rb3Be]3+[B6]6–[Be′Rb′3]3+ (D3d) changes to [Rb3Be]2+[B6]6–[Be′Rb′3]4+ (C3v), accompanying high-performance NLO switchable effect for both static and dynamic first hyperpolarizability (β0). [Rb3Be]3+[B6]6–[Be′Rb′3]3+ (off-form) owns zero of dipole moment (μ0) and β0, while [Rb3Be]2+[B6]6–[Be′Rb′3]4+ (on-form) exhibits a μ0 of 3.36 D and a β0e of 2.18 × 105 au. The different dynamic first hyperpolarizabilities between [Rb3Be]3+[B6]6–[Be′Rb′3]3+ and [Rb3Be]2+[B6]6–[Be′Rb′3]4+ are also significant. This indicates that Rb3BeB6Be′Rb′3 is a potential candidate for an IMSR NLO switch.