A Large Family of Dysprosium-based Trimetallic Nitride Endohedral Fullerenes: Dy3N@C2n (39 ≤ n ≤ 44)

Abstract

Dysprosium-based trimetallic nitride endohedral fullerenes (clusterfullerenes)-the Dy(3)N@C(2)(n) (38 </= n </= 49) family-have been produced at overwhelming yields compared to the empty fullerenes for the first time. The Dy(3)N@C(2)(n) family represents the largest clusterfullerene family explored up to now, even in comparison with the Tm(3)N@C(2)(n) (38 </= n </= 44) family which was discovered very recently. A series of 10 Dy(3)N@C(2)(n) clusterfullerenes (39 </= n </= 44, 1-9) have been isolated successfully and characterized by HPLC, mass spectrometry, and UV-vis-NIR spectroscopy. The study on the HPLC elution behavior reveals that there are two isomers for Dy(3)N@C(78) and Dy(3)N@C(84). Furthermore, a third isomer of Dy(3)N@C(80) is isolated for the first time. The optimum production conditions (Dy:C = 1:15, NH(3) pressure = 20 mbar) have been determined by investigating the effects of the Dy:C ratio and NH(3) pressure on the yields of the Dy(3)N@C(2)(n) clusterfullerenes. UV-vis-NIR spectroscopic study indicates that the Dy(3)N@C(2)(n) clusterfullerenes with small cages (n = 39-41) are large band-gap (1.38 approximately 1.51 eV) materials, while the band-gaps for those with larger cages (n = 42-44) are significantly smaller (0.80 approximately 0.84 eV).