89Y and 13C NMR cluster and carbon cage studies of an yttrium metallofullerene family, Y3N@C(2n) (n = 40-43).
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 Kratschmer-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.
Fu
Wujun
W
Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24060, USA.
Xu
Liaosa
L
Azurmendi
Hugo
H
Ge
Jiechao
J
Fuhrer
Tim
T
Zuo
Tianming
T
Reid
Jonathan
J
Shu
Chunying
C
Harich
Kim
K
Dorn
Harry C
HC
D002244:Carbon / Q000737:chemistry*; D037741:Fullerenes / Q000737:chemistry*; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D015019:Yttrium / Q000737:chemistry*
D037741:Fullerenes; D015019:Yttrium; D002244:Carbon