89 Y and 13 C NMR Cluster and Carbon Cage Studies of an Yttrium Metallofullerene Family, Y 3 N@C 2n (n ) 40-43) Wujun Fu, Liaosa Xu, Hugo Azurmendi, Jiechao Ge, Tim Fuhrer, Tianming Zuo, Jonathan Reid, Chunying Shu, Kim Harich, and Harry C. Dorn* Department of Chemistry, Virginia Polytechnic Institute and State UniVersity, Blacksburg, Virginia 24060 Received March 23, 2009; E-mail: hdorn@vt.edu Abstract: The members of a new family of yttrium trimetallic nitride-templated (TNT) endohedral metallofullerenes (EMFs), Y 3 N@C 2n (n ) 40-43), have been synthesized and purified. On the basis of experimental and computational 13 C NMR studies, we propose cage structures for Y 3 N@I h -C 80 (IPR allowed), Y 3 N@D 5h -C 80 (IPR allowed), Y 3 N@C s -C 82 (non-IPR), Y 3 N@C s -C 84 (non-IPR), and Y 3 N@D 3 -C 86 (IPR allowed). A significant result is the limited number of isomers found for each carbon cage. For example, there are 24 isolated pentagon rule (IPR) and 51 568 non-IPR structures possible for the C 84 cage, but only one major isomer of Y 3 N@C s -C 84 was found. The current study confirms the unique role of the trimetallic nitride (M 3 N) 6+ cluster template in the Kra ¨ tschmer-Huffman electric-arc process for fullerene cage size and high symmetry isomer selectivity. This study reports the first 89 Y NMR results for Y 3 N@I h -C 80, Y 3 N@C s (51365)-C 84 , and Y 3 N@D 3 (19)-C 86 , which reveal a progression from isotropic to restricted (Y 3 N) 6+ cluster motional processes. Even more surprising is the sensitivity of the 89 Y NMR chemical shift parameter to subtle changes in the electronic environment at each yttrium nuclide in the (Y 3 N) 6+ cluster (more than 200 ppm for these EMFs). This 89 Y NMR study suggests that 89 Y NMR will evolve as a powerful tool for cluster motional studies of EMFs. 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