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 [Zn-2](2+) species is rare. We succeeded in preparing a stable [Zn-2](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 angstrom due to the Zn+-Zn+ scattering and at 9660.7 eV due to the 1s-sigma* (the anti-bonding orbital comprised of the 4s-4s orbital) transition of the [Zn-2](2+) species. This species also gives the characteristic band around 42 000 cm(-1) due to its sigma-sigma* transition. Furthermore, UV-irradiation corresponding to the sigma-sigma* transition causes the bond dissociation, forming two unprecedented Zn+ ions, and detached Zn+ ions were recombined through heat-treatment at 573 K: [Zn+-Zn+] reversible arrow 2Zn(+). These processes were reproduced by applying the DFT calculation method to the assumed triplet, sigma(alpha)-sigma*(alpha), 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.