title: Quantum chemical insight of the dimetallic sulfide endohedral fullerene Sc2S@C70: does it possess the conventional D(5h) cage?
abstract: Like C(60), C(70) is one of the most representative fullerenes in fullerene science. Even though there are 8149 C(70) isomers, only two of them have been found before: the conventional D(5h) and an isolated pentagon rule (IPR)-violating C(2v)(7854). Through the use of quantum chemical methods, we report a new unconventional C(70) isomer, C(2)(7892), which survives in the form of dimetallic sulfide endohedral fullerene Sc(2)S@C(70). Compared with the IPR-obeying C(70) and the C(2v)(7854) fullerene with three pairs of pentagon adjacencies, the C(2)(7892) cage violates the isolated pentagon rule and has two pairs of pentagon adjacencies. In Sc(2)S@C(2)(7892)-C(70), two scandium atoms coordinate with two pentalene motifs, respectively, presenting two equivalent Sc-S bonds. The strong coordination interaction, along with the electron transfer from the Sc(2)S cluster to the fullerene cage, results in the stabilization of the non-IPR endohedral fullerene. The electronic structure of Sc(2)S@C(70) can be formally described as [Sc(2)S](4+)@[C(70)](4-); however, a substantial overlap between the metallic orbitals and cage orbitals has also been found. Electrochemical properties and electronic absorption, infrared, and (13)C NMR spectra of Sc(2)S@C(70) have been calculated theoretically.
authors.affiliation: Institute for Chemical Physics & Department of Chemistry, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, P.R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhao
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nagase