Synthesis of an unexpected [Zn₂]²⁺ species utilizing an MFI-type zeolite as a nano-reaction pot and its manipulation with light and heat

Compared with mercury, the existence of [Zn₂]²⁺ species is rare. We succeeded in preparing a stable [Zn₂]²⁺ species by utilizing an MFI-type zeolite as a nano-reaction pot, which was confirmed using XAFS spectroscopy: the bands at R = 2.35 Å due to the Zn⁺-Zn⁺ scattering and at 9660.7 eV due to the 1s-σ∗ (the anti-bonding orbital comprised of the 4s-4s orbital) transition of the [Zn₂]²⁺ species. This species also gives the characteristic band around 42000 cm^-1 due to its σ-σ∗ transition. Furthermore, UV-irradiation corresponding to the σ-σ∗ transition causes the bond dissociation, forming two unprecedented Zn⁺ ions, and detached Zn⁺ ions were recombined through heat-treatment at 573 K: [Zn⁺-Zn⁺] 2Zn⁺. These processes were reproduced by applying the DFT calculation method to the assumed triplet, σ(α)-σ∗(α), structure formed on the M7-S2 site with the specific Al array in the MFI-type zeolite. Research into the specific field using zeolites to synthesize "ultra-state ions" is very promising. This journal is