Efficient Synthesis of Endohedral Metallofullerenes in 3-Phase Arc Discharge

Abstract

Endohedral metallofullerenes and, in particular, trimetallic nitride endohedral metallofullerenes exhibit unique properties that differentiate them from other carbon nanomaterials. Future applications of these species are restricted due to high cost and low productivity of existing synthesis methods, which are primarily based on the use of a Kr€ atschmer-Huffman two electrode in-line arc discharge reactor with packed electrodes. We have developed an alternative way for the synthesis of metallofullerenes that employs a 3-phase arc discharge system. The method has been validated and optimized for the synthesis of trimetallic nitride endohedral metallofullerenes, including Lu 3 N@C 80 . Experimental results have shown more than 400% increase in Lu 3 N@C 80 yield and productivity, while eliminating the use of high cost process gases (i.e., helium). Moreover, a metal oxide powder feed and solid graphite electrodes are introduced to avoid the need for packed electrodes and to extend reactor run times.

High Blocking Temperature of Magnetization and Giant Coercivity in the Azafullerene Tb2@C79N with a Single‐Electron Terbium–Terbium Bond

“…Tb 2 @C 79 N was previously prepared via a Krätschmer‐Huffman electric‐arc process with a He/N 2 (280/20 torr) atmosphere by vaporizing packed Tb 4 O 7 graphite rods, but the sample for the current study was synthesized by a 3‐phase electric arc discharge evaporation of graphite rods with Tb 4 O 7 powder injection into the 3‐phase electric arc zone in only a N 2 atmosphere . This leads to a significant change in the EMF distribution with a higher concentration of nitrogen containing metallofullerene species after a usual amino silica separation step (Figure S1–S3 in the Supporting Information) .…”

Tb2O@C2(13333)-C74: A Non-Isolated Pentagon Endohedral Fullerene Containing a Nearly Linear Tb–O–Tb Unit

“…A sample of Tb 2 O@C 2 (13333)-C 74 was obtained as a byproduct from the earlier preparation of the azafullerene Tb 2 @C 79 N. 13 Carbon soot containing Tb 2 O@C 2 (13333)-C 74 was synthesized by the three-phase electric arc discharge evaporation of graphite rods doped with Tb 4 O 7 powder under an atmosphere of dinitrogen. 32 The soot was subjected to a chemical separation using amino-functionalized silica, 33 followed by several rounds of HPLC on different columns as outlined in the Experimental Section. Figure 1 shows the HPLC trace of the purified material along with the experimental and computed mass spectra.…”

Water-soluble fullerenes for medical applications

“…A further step towards commercial synthesis of TNT EMFs was achieved by Bezmelnitsyn et al 53 whose novel approach to arc discharge, they estimate, has reduced the cost of lutetium-containing TNT EMF synthesis by 70-80%. A three-fold increase in yield was achieved by using a pyramidal three-phase AC arc discharge setup (cf.…”