| Research Abstract |
Electorcrystallization of the chlorobenzene/ethanol solution containing C_<60> and cationic dye, e.g., brilliant green, crystal violet, and other triphenylmethane dyes resulted in the crystalline C_<60> fulleride compounds.Discrete fulleride anions have drawn much attention, as the electron-accepting ability of C_<60>is its most characteristic chemical properties.The C_<60> ability as electron acceptors leads to intriguing physical properties, such as superconducting of alkali metal doped C_<60> as well as unique ferromagnetic behavior of TDAE-C_<60>.However, there has been rather limited number of well-characterized C_<60> anion radical salts, mainly because of the extreme air sensitivity.
Although several different ways to synthesize(Dye)(C_<60>) compounds were.reported, no single crystals were so far obtained.We have recently succeeded in obtaining the single-crystal C_<60> anion radical salts stabilized by cationic organic dyes, e.g., Brilliant Green. SEM microphotograph of the blac
… More
k-colored these crystalline materials shows needle-type single crystal of C_<60> salts of several cationic dyes. The profile of the JR spectra of the salts seems to change significantly. Only 526 cm^<-1> and 577 cm^<-1> peaks from C_<60> were observable, however, the peaks between 1000 cm^<-1> and 1300 cm^<-1> based on dye cations were disappeared completely. This means the charge transfer interaction exists in some way, and not the mixture of two components.
ESR spectra of the salts under Ar atmosphere demonstrate that the broad signal (g=1.999, AHpp=ca. 44 G) superimposed by sharp signal (g=2.001, ΔH_<pp>=ca.5 G), which is characteristic feature of the ESR of C_<60> anion radicals. The time-course of the.ESR spectra shows the degradation, observed by the broad signal disappeared in several weeks.The X-ray crystal structure analysis of (Brilliant Green)^+(C_<60>)^-definitely confirms 1:1 salts of C_<60> and cationic dye, Brilliant Green.The transport phenomena on the basis of the four-probe electronic conductivity measurements demonstrate that the the semicondcuting behavior, despite the high resistivity, were obtained for these fulleride salts stabilized by cationic dyes. Less
|
