Enhanced Dipole Moments in Trimetallic Nitride Template Endohedral Metallofullerenes with the Pentalene Motif

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• 作者：Jianyuan Zhang ; Daniel W. Bearden ; Tim Fuhrer ; Liaosa Xu ; Wujun Fu ; Tianming Zuo ; Harry C. Dorn
• 刊名：The Journal of the American Chemical Society
• 出版年：2013
• 出版时间：March 6, 2013
• 年：2013
• 卷：135
• 期：9
• 页码：3351-3354
• 全文大小：317K
• 年卷期：v.135,no.9(March 6, 2013)
• ISSN：1520-5126

文摘

Although not found to date in empty-cage fullerenes, the fused pentagon motifs (pentalenes) are allowed in endohedral metallofullerenes (EMFs). We have found that members of the trimetallic nitride template (TNT) EMF Y₃N@C_2n (n = 39鈥?4) family that contain pentalene motifs exhibit significant dipole moments. This finding is predicted to be significant for other EMFs with a metal atom orientated toward the pentalene motif. Chromatographic retention data and computational results for Y₃N@C₂-C₇₈, Y₃N@C_s-C₈₂, and Y₃N@C_s-C₈₄ are examples that pentalene groups lead to a significant induced dipole moment (1D). A special case is the Y₃N@C₂-C₇₈ that contains two pentalenes in a relatively small cage. The ¹³C NMR spectrum for Y₃N@C₂-C₇₈ exhibits strongly deshielded signals for the fullerene cage (155鈥?70 ppm) supporting the presence of the pentalene motif. In addition, a lengthening of the covalent M鈥揘 bond in the internal M₃N cluster is found for all reported TNT EMFs that contain one or two pentalene motifs.