No abstract

was successfully synthesized and isolated by multistage HPLC for the first time. All of these isolated metallofullerenes were confirmed by LD-TOF mass spectrometry and characterized by UV-vis-NIR absorption spectroscopy. The valence state of the encaged ytterbium atoms, the probable molecular symmetries, and the electronic structures are discussed in terms of their HPLC behaviors and absorption spectra. In particular, two new mono-metallofullerene isomers based on C 74 and C 84 cages were isolated for the first time that are proposed to have completely novel cage structures not reported elsewhere so far.

The nonresonant third-order hyperpolarizability of all-carbon molecules C60 is measured by nanosecond degenerate four-wave-mixing experiment in C60 toluene solution. The value of γ1111 measured is 1.6×10−31 esu, which corresponds to an estimated value of the third-order nonlinear optical susceptibility χ(3)1111E = 3.3 × 10−9 esu for the solid compound.

On the basis of high-yield preparation, arc-produced soot containing endohedral Y, La, Nd, Sm, Gd, Tb, Yb, Ca, and Ba fullerenes are successively extracted with carbon disulfide, N,N-dimethylformamide, pyridine, and aniline. The continuous four-step extraction procedure generates endohedral metallofullerenes (EMFs) with high content and abundant species, and novel EMFs such as Tb@C66, Yb@C60, and Tb3@C80 were extracted. This makes it possible for us to systemically study the varying extraction behaviors of divalent and trivalent metallofullerenes. Trivalent EMFs are characterized by higher content and multimetallofullerenes, whereas divalent species are characterized by lower content and solely monometallofullerenes. A positive relationship between the content and the species abundance of EMFs is proposed. The differences in extracting ability of the above solvents toward certain EMFs are summarized and explained on the basis of the number of transferred electrons from the encaged metal atom(s), the back-donation from carbon cages, and the solvent reduction of EMFs.