화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.134, No.41, 16937-16940, 2012
Superatom Electron Configuration Predicts Thermal Stability of Au-25(SR)(18) Nanoclusters
The exceptional stability of ligand-stabilized gold nanoclusters such as Au-25(SC6H13)(18)(-), Au-39(PR3)(14)X-6(-), and Au-102(SR)(44) arises from the total filling of superatomic electron shells, resulting in a "noble-gas superatom" electron configuration. Electrochemical manipulation of the oxidation state can add or remove electrons from superatom orbitals, creating species electronically analogous to atomic radicals. Herein we show that oxidizing the Au-25(SR)(18)(-) superatom from the noble-gas-like 1S(2)1P(6) electron configuration to the open-shell radical 1S(2)1P(5) and diradical 1S(2)1P(4) configurations results in decreased thermal stability of the compound, as measured by differential scanning calorimetry. Similar experiments probing five oxidation states of the putatively geometrically stabilized Au-144(SR)(60) cluster suggest a more complex relationship between oxidation state and thermal stability for this compound.