title: Nanoscale fullerene compression of an yttrium carbide cluster.
abstract: The nanoscale parameters of metal clusters and lattices have a crucial influence on the macroscopic properties of materials. Herein, we provide a detailed study on the size and shape of isolated yttrium carbide clusters in different fullerene cages. A family of diyttrium endohedral metallofullerenes with the general formula of Y(2)C(2n) (n = 40-59) are reported. The high field (13)C nuclear magnetic resonance (NMR) and density functional theory (DFT) methods are employed to examine this yttrium carbide cluster in certain family members, Y(2)C(2)@D(5)(450)-C(100), Y(2)C(2)@D(3)(85)-C(92), Y(2)C(2)@C(84), Y(2)C(2)@C(3v)(8)-C(82), and Y(2)C(2)@C(s)(6)-C(82). The results of this study suggest that decreasing the size of a fullerene cage with the same (Y(2)C(2))(4+) cluster results in nanoscale fullerene compression (NFC) from a nearly linear stretched geometry to a constrained "butterfly" structure. The (13)C NMR chemical shift and scalar (1)J(YC) coupling parameters provide a very sensitive measure of this NFC effect for the (Y(2)C(2))(4+) cluster. The crystal structural parameters of a previously reported metal carbide, Y(2)C(3) are directly compared to the (Y(2)C(2))(4+) cluster in the current metallofullerene study.
authors.affiliation: Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, 24060, United States.
authors.forename: Jianyuan
authors.initials: J
authors.lastname: Zhang
authors.forename: Tim
authors.initials: T
authors.lastname: Fuhrer
authors.forename: Wujun
authors.initials: W
authors.lastname: Fu
authors.forename: Jiechao
authors.initials: J
authors.lastname: Ge
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Bearden
authors.forename: Jerry
authors.initials: J
authors.lastname: Dallas
authors.forename: James
authors.initials: J
authors.lastname: Duchamp
authors.forename: Kenneth
authors.initials: K
authors.lastname: Walker
authors.forename: Hunter
authors.initials: H
authors.lastname: Champion
authors.forename: Hugo
authors.initials: H
authors.lastname: Azurmendi
authors.forename: Kim
authors.initials: K
authors.lastname: Harich
authors.forename: Harry C
authors.initials: HC
authors.lastname: Dorn