An Expanded Family of Dysprosium-Scandium Mixed-Metal Nitride Clusterfullerenes: The Role of the Lanthanide Metal on the Carbon Cage Size Distribution

摘要

ZA large family of dysprosium-scandium (Dy-Sc) mixed-metal nitride clusterfullerenes (MMNCFs), DyxSc3-xN@C-2n (x = 1, 2, 2n = 68, 70, 76-86) have been successfully synthesized and isolated. Among these, the C-70 and C-82-based MMNCFs are two new cages that have never been isolated for MMNCFs. Synthesis of DyxSc3-xN@C-2n was accomplished by the "selective organic solid" route using guanidinium thiocyanate as the nitrogen source, and their isolation was fulfilled by recycling HPLC. UV/Vis-NIR spectroscopic study indicates that almost all DyxSc3-xN@C-2n MMNCFs are kinetically stable fullerenes with optical band gaps beyond 1 eV. This feature is distinctly different to their counterparts Dy3N@C-2n (78 <= 2n <= 88), whose for optical band-gaps are below 1 eV for relatively large cages such as C-84 and C-86. An FTIR spectroscopic study in combination with DFT calculations enables reasonable assignments of the cage isomeric structures of all isolated DyxSc3-xN@C-2n (x = 1, 2, 2n = 68, 70, 76-86) MMNCFs. The carbon cage size distribution of DyxSc3-xN@C-2n (2n = 68, 70, 76-86) is compared to the reported Dy3N@C-2n (78 <= 2n <= 8) homogeneous NCF and Dy(x)Sc(3-)xN@C-2n (78 <= 2n <= 88) MMNCF families, revealing that the medium-sized Dy metal plays a crucial role on the expanded cage size distribution of MMNCFs. As a result, DyxSc3-xN@C-2n MMNCFs are the largest MMNCF family reported to date.