Title page for ETD etd-12172009-162249


Type of Document Dissertation
Author Fu, Wujun
Author's Email Address wjfu@vt.edu
URN etd-12172009-162249
Title Preparation, Separation, Characterization and Hydrogenation of Endohedral Metallofullerenes
Degree PhD
Department Chemistry
Advisory Committee
Advisor Name Title
Dorn, Harry C. Committee Chair
Gibson, Harry W. Committee Member
Heflin, James R. Committee Member
Morris, John R. Committee Member
Ritter, Alfred L. Committee Member
Keywords
  • Metal-carbide
  • Metalloheterofullerene
  • Metallofullerene
  • Hydrogenation
  • Endohedral
  • Yttrium-based
  • Di-metallic
Date of Defense 2009-12-10
Availability unrestricted
Abstract
Endohedral metallofullerenes (EMFs) have attracted increasing attention during past decades due to their novel structures and potential applications in a variety of fields such as biomedical applications and molecular electronics. This dissertation addresses the structural characterization and hydrogenation of EMFs. A family of novel large cage yttrium-based TNT EMFs Y3N@C2n (n=40-44) was prepared, separated, and structurally characterized for the first time. The structure of Y3N@C2n (n=40-44) is proposed by the experimental and computational 13C NMR studies. The first 89Y NMR results for Y3N@Ih-C80, Y3N@Cs-C84 and Y3N@D3-C86 reveal a progression from isotropic to restricted (Y3N)6+ cluster motional processes.

The di-metallic EMF Y2C94 is distinguished as a metal-carbide based EMF, Y2C2@D3-C92. The carbide within the cage is successfully detected by 13C NMR. The scalar JY-C coupling between the yttrium atoms and the C2 unit within the C92 cage is successfully observed, suggesting the C2 unit rotates rapidly around the yttrium atoms.

Two paramagnetic endohedral metalloheterofullerenes, Y2@C79N and Gd2@C79N, were also synthesized and characterized. The EPR study demonstrated that the spin density is mainly localized between the two metallic ions. A spin-site exchange system could be constructed between Y2@C79N and the organic donor TMPD. Being a unique paramagnetic material, Gd2@C79N displays an unusual stability over a wide temperature range, which could be very useful in optical and magnetic areas.

Functionalization of EMFs is another point of interest in this dissertation. Hydrogenated Sc3N@C80 was synthesized and characterized. Our study demonstrated that the Sc3N@C80 can be fully hydrogenated and the pristine Sc3N@C80 can be recovered from Sc3N@C80H80 after being heated in vacuum. The hydrogenated EMFs could be potential hydrogen storage materials.

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