Organic compounds -- part of the class 532-570 series – Organic compounds – Radioactive metal containing
Reexamination Certificate
1999-12-10
2001-10-16
Nazario-Gonzalez, Porfirio (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Radioactive metal containing
C534S015000, C556S001000, C556S028000, C505S460000, C423S44500R
Reexamination Certificate
active
06303760
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to an endohedral metallofullerene and a method for the making the same. More particularly the present invention is directed to a trimetallic nitride endohedral metallofullerene and a method for making the same.
Fullerenes are a family of closed-caged molecules made up of carbon atoms. The closed-caged molecules consist of a series of five and six member carbon rings. The fullerene molecules can contain 500 or more carbon atoms. The most common fullerene is the spherical C
60
molecule taking on the familiar shape of a soccer ball.
Fullerenes are typically produced by an arc discharge method using a carbon rod as one or both of the electrodes in a Krätschmer-Huffman generator. Krätschmer, W. et al., Chem. Phys. Lett., 170, 167-170 (1990) herein incorporated by reference in its entirety. Typically the generator has a reaction chamber and two electrodes. The reaction chamber is evacuated and an inert gas is introduced in the reaction chamber at a controlled pressure. A potential is applied between the electrodes in the chamber to produce an arc discharge. The arc discharge forms a carbon plasma in which fullerenes of various sizes are produced.
Many derivatives of fullerenes have been prepared including encapsulating metals inside the fullerene cage. Metal encapsulated fullerenes are typically prepared by packing a cored graphite rod with the metal oxide of the metal to be encapsulated in the fullerene cage. The packed graphite rod is placed in the generator and arc discharged to produce fullerene products. The formation of metal encapsulated fullerences is a complicated process and typically yields only very small amounts of the metal fullerenes.
Fullerenes and their derivatives are useful as superconductor materials, catalysts, and nonlinear optical materials. Fullerene compounds can also find utility as molecular carriers for drugs or catalysts. Fullerenes containing radioactive metals can be useful in missile therapy for cancer and as a radionuclide tracer.
SUMMARY OF THE INVENTION
The present invention is directed to a family of endohedral metallofullerenes having the formula A
3-n
X
n
N@C
m
(n=0-3). Further the present invention is directed to the formation of endohedral metallofullerenes by a trimetallic nitride template process (“TNT”).
Accordingly, the present invention is directed to an endohedral metallofullerene having the formula A
3-n
X
n
N@C
m
wherein A is a metal, X is a second trivalent metal, n is an integer from 0 to 3, and m is an even integer from about 60 to about 200. The integer m may take on values ranging from about 60 to about 100. Typically, m is about 68, 78, or 80. Further, x may be a trivalent metal and has an ionic radius below about 0.095 nm, and A is a trivalent metal having an ionic radius below about 0.095 nm.
In accordance with the present invention, A may be an element selected from the group consisting of a rare earth element and a group IIIB element. Further, A may be selected from the group consisting of Scandium, Yttrium, Lanthanum, Gadolinium, Holmium, Erbium, Thulium, and Ytterbium. X may be an element selected from the group consisting of a rare earth element and a group IIIB element. Still further, X may be selected from the group consisting of Scandium, Yttrium, Lanthanum, Gadolinium, Holmium, Erbium, Thulium, and Ytterbium.
The present invention also includes a method for making a trimetallic nitride endohedral metallofullerene. The method includes charging a reactor with a first metal, carbon, and nitrogen; and reacting the nitrogen, the first metal, and the carbon in the reactor to form an endohedral metallofullerene. The nitrogen may be introduced in the reactor in the form of nitrogen gas and the first metal and carbon are introduced in the reactor in the form of a rod filled with a mixture of a first metal oxide and graphite wherein the first metal oxide is an oxide of the first metal.
The first metal is selected from the group consisting of a rare earth element and a group IIIB element. Typically, the first metal is selected from the group consisting of Scandium, Yttrium, Lanthanum, Gadolinium, Holmium, Erbium, Thulium, and Ytterbium. The first metal may have an ionic radius below about 0.095 nm. Further, the first metal may be a trivalent metal.
The mixture comprises from about 1% to about 5% first metal oxide by weight. Typically the mixture comprises about 3% first metal oxide by weight.
The method further includes reacting the nitrogen, carbon, and first metal further comprises vaporizing the carbon and the first metal in the presence of the nitrogen. The nitrogen may be introduced in the reactor in the form of a carbon nitride or a metal nitride wherein the metal nitride contains the metal to be encapsulated in the fullerene cage.
Still further the method includes adding from about 1 to about 450 mg of cobalt oxide to the mixture of metal oxide and graphite. Typically, the mixture comprises from about 75 to about 225 mg of cobalt oxide.
The method further includes charging the reactor with a first metal, a second metal, carbon and nitrogen and reacting the second metal, the first metal, carbon, and nitrogen to produce the endohedral metallofullerene. In accordance with the present invention, the nitrogen may be introduced in the reactor in the form of nitrogen gas; and the first metal, the second metal, and the carbon are introduced in the reactor in the form of a rod filled with a mixture of a first metal oxide, a second metal oxide, and graphite wherein the first metal oxide is an oxide of the first metal and the second metal oxide is an oxide of the second metal.
The first metal is selected from the group consisting of a rare earth element and a group IIIB element; and the second metal is selected from the group consisting of a rare earth element and a group IIIB element. Typically, the first metal is selected from the group consisting of Scandium, Yttrium, Lanthanum, Gadolinium, Holmium, Erbium, Thulium, and Ytterbium; and the second metal is selected from the group consisting of Scandium, Yttrium, Lanthanum, Gadolinium, Holmium, Erbium, Thulium, and Ytterbium. Further, the first and second metals may have an ionic radius below about 0.095 nm. Still further, the first and second metal may be trivalent metals.
The method includes a mixture having from about 1% to about 5% first metal oxide by weight and from about 1% to about 5% second metal oxide by weight. Typically, the mixture has about 3% first metal oxide and about 2% second metal oxide by weight.
The method further includes reacting the nitrogen, carbon, first metal and second metal further comprises vaporizing the carbon, first metal and second metal in the presence of the nitrogen. The nitrogen may be introduced in the reactor in the form of a carbon nitride or a metal nitride wherein the metal nitride contains the metal to be encapsulated in the fullerene cage.
The mixture may have from about 1 to about 450 mg of cobalt oxide. Typically the mixture has about 75 to about 225 mg of cobalt oxide.
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Dorn Harry C.
Stevenson Steven A.
McGuireWoods LLP
Nazario-Gonzalez Porfirio
Virginia Tech Intellectual Properties Inc.
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