Tetsu Yonezawa1 Yohei Ishida1 Mai Thanh Nguyen1 Kunihiro Narita1 Ryan Corpuz1

1, Hokkaido Univ, Sapporo, , Japan

Quaternary ammonium is a cationic group which is always show positive change at any pH conditions. Many reports have been published on thiolate-gold nanoclusters but almost all of them were covered by non-ionic or anionic thiol compounds. Only a few reports of amino-thiol-stabilized gold nanoclusters can be found but no report of quaternary ammonium thiolate-stabilized ones. For the first time, we prepared quaternary ammonium-stabilized fluorescent gold nanoclusters by sputtering processes. Furthermore, we have successfully prepared Au25 clusters stabilized by quaternary ammonium thiols. In this case, counter anion plays an important key. Bromides cannot well stabilize Au25 clusters and they decomposed rapidly. But after changing this counter anion to PF6- or other soft anions, very stable fully cationic Au25 nanoclusters could be obtained.