Fullerene derivatives, methods of preparing them and their use

Fullerene derivatives, methods of preparing the same and methods of using the same, wherein the fullerene derivatives are of the formula I ##STR1##

This application is a 371 of application PCT/EP/01079 filed Apr. 7, 1994. 
Fullerenes are cage-like carbon allotropes of the formula (C.sub.20+2m) 
(where m=a natural number). They contain twelve five-membered rings and 
also any number, but at least two, six-membered rings of carbon atoms. 
Although this class of compound was discovered only in 1985 by Kroto and 
Smalley (Nature, 1985, 318, 162) and Kratschmer and Huffman only reported 
the preparation of macroscopic amounts of C.sub.60 in 1990 (Nature 1990, 
347, 354), such compounds have very quickly attracted wide interest and 
within a very short time have become the subject of numerous research 
studies (see, for example, G. S. Hammond, V. J. Kuck (Editors), 
Fullerenes, American Chemical Society, Washington D.C. 1992 and Accounts 
of Chemical Research, March edition 1992). 
Since a high potential is expected of this class of substances, for example 
in the fields of optoelectronics and research on active compounds, efforts 
have already been made to form derivatives, in particular of C.sub.60 
(see, for example, H. Schwarz, Angew, Chem. 1992, 104, 301 and F. Wudl et 
al. in G. S. Hammond, V. J. Kuck (Editors), Fullerenes, American Chemical 
Society, Washington D.C. 1992 and Accounts of Chemical Research, March 
edition 1992). 
Some experiments on forming derivatives succeeded in isolating defined 
products. Examples are the reactions of fullerenes in 1.3 dipolar 
cycloadditions with diazo compounds (e.g. F. Wudl et al., Acc. Chem. Res. 
1992, 25, 157) and also in 2+1! carbene additions with nucleophilic 
glycosylidenecarbenes (e.g. A. Vasella et al., Angew. Chem. 1992, 104, 
1383). 
Further examples are the addition of nucleophiles such as organolithium and 
organomagnesium compounds (e.g. A. Hirsch et al., Angew. Chem. 1992, 104, 
808). 
It was desirable to synthesize fullerene derivatives containing structural 
units having those functional groups which are known to have applications 
in the field of research on active compounds, which can also be utilized 
for the construction of new polymer materials and which improve the 
physical properties, such as solubility or polarity, of the fullerene 
derivatives. 
It has long been known that 1,3-dicarbonyl compounds such as malonic esters 
and .beta.-ketoesters have proven useful in the synthesis of active 
compounds (e.g. Organikum 16, intended edition 1986, pages 393, 413, 414). 
The linking of acid C-H compounds, such as malonic esters or 
.beta.-ketoesters, with activated olefins is known as the Michael edition 
(e.g. Organikum 16, intended edition 1986, page 507). It has now been 
found that well-defined fullerene derivatives can be obtained by reacting 
fullerenes, for example, with the anions of 2-halocarbonyl compounds. 
The invention provides a fullerene derivative of the formula I 
##STR2## 
in which the symbols and indices have the following meanings: F: is a 
fullerene radical of the formula C.sub.(20+2m) where m=20, 25, 28, 29; 
E.sup.1, E.sup.2 : are identical or different and are each COOH, COOR, 
CONRR.sup.1, CHO, COR, CN, P(O)(OR).sub.2 and SO.sub.2 R, where R, R.sup.1 
are each a straight-chain or branched, aliphatic radical (C.sub.1 to 
C.sub.20) which may be unsubstituted or monosubstituted or polysubstituted 
by identical or different substituents, in which radical up to every third 
CH.sub.2 unit can be replaced by O or NR.sup.4, where R.sup.4 is (C.sub.1 
-C.sub.20)-alkyl or benzyl, or a benzyl radical or phenyl radical which 
can be unsubstituted or substituted by from 1 to 5 substituents R, OH, OR, 
COOR, OCOR, SO.sub.3 H, SO.sub.2 Cl, F, Cl, Br, NO.sub.2 and CN or 
together are 
##STR3## 
or are different from one another and are each COR, R or H, or are 
different from one another and are each COR/R or F/Cl/Br, where R is as 
defined above, or are different from one another and are each NO.sub.2, 
R.sup.3 or H, where R.sup.3 is an unsubstituted, monosubstituted or 
polysubstituted aliphatic radical (C.sub.1 to C.sub.20); 
n: is a natural number from 1 to 10+m where m=20, 25, 28, 29. 
Preference is given to compounds of the formula I in which the symbols and 
indices have the following meanings: 
F: is a fullerene radical of the formula C.sub.(20+2m) where m=20, 25, 28, 
29, 
E.sup.1, E.sup.2 : are identical or different and are each COOR, COR, 
P(O)(OR).sub.2, COOH, CN, where R is a straight-chain or branched, 
aliphatic radical (C.sub.1 to C.sub.20) which may be unsubstituted or 
monosubstituted or polysubstituted by identical or different substituents, 
in which radical up to every third CH.sub.2 unit can be replaced by O or 
NR.sup.4, where R.sup.4 =(C.sub.1 -C.sub.20)-alkyl or benzyl, or a benzyl 
radical or phenyl radical which can be unsubstituted or substituted by 
from 1 to 3 substituents R, OH, OR, COOR, OCOR, SO.sub.3 H, SO.sub.2 Cl, 
F, Cl, Br, NO.sub.2 and CN, or together are 
##STR4## 
or are different from one another and are each COR, R or H, or are 
different from one another and are each COR/R or F/Cl/Br, 
n : is a natural number from 1 to 12. 
Particular preference is given to compounds of the formula I in which the 
symbols and indices have the following meanings: 
F: C.sub.60, C.sub.70 
E1/E2: CO.sub.2 R.sup.1 /CO.sub.2 R.sup.2 ; CO.sub.2 R.sup.1 /COR.sup.2 ; 
CO.sub.2 R.sup.1 /CN; COAr/R.sup.1 or H; COAr/R.sup.1 or Cl; 
##STR5## 
COR.sup.1 /COR.sup.2 ; P(O)(OR.sup.1).sub.2 /P(O)(OR.sup.2).sub.2 ; 
COOH/COOH; where R.sup.1 and R.sup.2 are identical or different and are 
each a straight-chain or branched alkyl radical (C.sub.1 to C.sub.20) 
which may be unsubstituted or monosubstituted or polysubstituted by 
identical or different substituents, in which radical every third CH.sub.2 
unit can be replaced by O or NR.sup.4, where R.sup.4 =(C.sub.1 -C20)-alkyl 
or benzyl, or a benzyl radical or phenyl radical which can be 
unsubstituted or substituted by from 1 to 3 substituents OH, OMe, CO.sub.2 
R.sup.1, OOCR.sup.1, SO.sub.3 H, SO.sub.2 Cl, F, Cl, Br, NO.sub.2 and CN, 
and Ar is a phenyl radical which can likewise be substituted by from 1 to 
3 substituents OH, OMe, Me, CO.sub.2 R.sup.1, OCOR.sup.1, SO.sub.3 H, 
SO.sub.2 Cl, F, Cl, Br, NO.sub.2 and CN or can be substituted by a 
straight-chain or branched aliphatic radical (C.sub.1 -C.sub.20), 
preferably C.sub.1 -C.sub.10, which may be unsubstituted or 
monosubstituted or disubstituted by identical or different substituents 
COOR.sup.5, CONHR.sup.5, CONR.sub.2.sup.5, CONH.sub.2, CONR.sup.6, COOH, 
OH or OCOR.sup.5, COOAr, COOCH.sub.2 Ar, where R.sup.5 = 
##STR6## 
C.sub.1 -C.sub.6 -alkyl, hydroxy-(C.sub.1 -C.sub.6)-alkyl, carboxy 
(C.sub.1 -C.sub.6)-alkyl or (C.sub.1 -C.sub.3)-alkylcarboxyl-(C.sub.1 
-C.sub.6)-alkyl; 
R.sup.6 =C.sub.11 -C.sub.17 -alkylene in which up to every 3rd CH.sub.2 
unit can be replaced by O and which together with the amide nitrogen forms 
a C.sub.12 -C.sub.18 ring, and Ar is as defined above; 
n: is a natural number from 1 to 6. 
Very particular preference is given to compounds of the formula I in which 
the symbols and indices have the following meanings: 
F: C.sub.60, C.sub.70 
E.sup.1 /E.sup.2 : CO.sub.2 Alkyl.sup.1 /CO.sub.2 Alkyl.sup.1 ; CO.sub.2 
Alkyl.sup.1 /COAlkyl.sup.2 ; COAr/Ar; COAr/Alkyl.sup.1 ; COAr/H 
where Alkyl.sup.1, Alkyl.sup.2 are each a straight-chain or branched alkyl 
radical having from 1 to 10 carbon atoms in which up to every third 
CH.sub.2 unit can be replaced by O, and Ar is a phenyl group which can be 
substituted by a straight-chain or branched aliphatic radical (C.sub.1 
-C.sub.6) which may be unsubstituted or monosubstituted or disubstituted 
by identical or different substituents COOR.sup.5, CONHR.sup.5, 
CONR.sub.2.sup.5, CONR.sup.6, COOH, OH or OCOR.sup.5, where R.sup.5 and 
R.sup.6 are as defined above, 
n: is 1 or 2. 
The straight-chain or branched aliphatic radical (C.sub.1 -C.sub.20) R, 
R.sup.1 can be, for example, preferably monosubstituted or disubstituted 
by identical or different substituents OH, COOH, COOAr, CONR.sub.2.sup.5, 
CONR.sup.6, OCOR.sup.5, COOCH.sub.2 Ar, CONHCH.sub.2 Ar, CONHAr, 
CONHR.sup.5, COOR.sup.5, halogen, CONH.sub.2, COCH.sub.2 Ar, COAr, CO 
(C.sub.1 -C.sub.6)-alkyl or CHO, where Ar, R.sup.5 and R.sup.6 are as 
defined above. 
The compounds of the invention having the formula I are prepared, for 
example, by cyclopropanation of fullerene with an .alpha.-halo-CH-acid 
compound in the presence of a suitable base (e.g. L. L. McCoy, J. Amer. 
Chem. Soc. 1958, 80, 6568) or by reaction of suitably functionalized 
cyclopropanated fullerene derivatives by known methods, with care having 
to be taken to ensure that the reagents used do not react with the 
electrophilic fullerene radical. 
The invention further provides the following process for preparing 
fullerene derivatives of the formula I 
##STR7## 
where F is a fullerene radical of the formula C.sub.(20+2m) where m=20, 
25, 28, 29, 
E.sup.1 and E.sup.2 are identical or different and are each COOH, COOR, 
CONRR.sup.1, CHO, COR, CN, P(O)(OR).sub.2 and SO.sub.2 R, where R, R.sup.1 
are each a straight-chain or branched aliphatic radical (C.sub.1 to C20) 
which may be unsubstituted or monosubstituted or polysubstituted by 
identical or different substituents, in which radical up to every third 
CH.sub.2 unit can be replaced by O or NR.sup.4, where R.sup.4 is (C.sub.1 
-C.sub.20)-alkyl or benzyl, or a benzyl radical or phenyl radical which 
can be unsubstituted or substituted by from 1 to 5 substituents R, OH, OR, 
COOR, OCOR, SO.sub.3 H, SO.sub.2 Cl, F, Cl, Br, NO.sub.2 and CN or 
together are 
##STR8## 
or are different from one another and are each COR, R or H, or are 
different from one another and are each COR/R or F/Cl/Br, or are different 
from one another and are each NO.sub.2, R.sup.3 or H, where R.sup.3 can be 
an unsubstituted, monosubstituted or polysubstituted aliphatic radical 
(C.sub.1 to C.sub.20), 
X is --Cl, --Br, --I, --OSO.sub.2 Ar, OSO.sub.2 CF.sub.3, OSO.sub.2 C.sub.4 
F.sub.9, 
base: is alkali metal hydride, alkali metal hydroxide, alkoxide, amide, 
amine, guanidine 
n is a natural number from 1 to 10+m where m=20, 25, 28, 29. 
Preference is given to a process for preparing compounds of the formula I, 
in which a fullerene of the formula C.sub.(20+2m) (m=20, 25, 28, 29) is 
reacted in an aprotic organic solvent such as toluene, chlorobenzene, 
benzene, CH.sub.2 Cl.sub.2 with compounds of the formula II in the 
presence of suitable bases in a temperature range from -78.degree. C. to 
180.degree. C., preferably from 0.degree. to 110.degree. C. and in 
appropriate cases at room temperature (20.degree.-30.degree. C.). 
The selection of the base depends on the pKa and the sensitivity of the CH 
acid compound to the base used. 
The preparation of compounds of the formula I where n=1 is carried out at 
approximate stoichiometry of the starting compounds, preferably in a 
temperature range from -78.degree. C. to +50.degree. C., particularly 
preferably at from 0.degree. C. to 50.degree. C. A higher degree of 
substitution and thus a greater value for n is achieved by using excess CH 
acid compound of the formula II and a sufficient amount of base and 
accelerating the reaction by heating, if appropriate, to above 100.degree. 
C. 
However, the compounds of the formula I obtainable by the process of the 
invention can also be prepared in well-defined form by means of subsequent 
reactions by, for example, an ester of the formula I being saponified to 
give the corresponding acid of the formula I or an alcohol of the formula 
I being reacted with an acid to give an ester of the formula I or an ester 
of the formula I being reacted with an amine to give the corresponding 
amide of the formula I. 
The fullerene used is preferably pure C.sub.60 and/or C.sub.70, but it is 
also possible to use crude fullerenes containing a mixture of C.sub.60 and 
C.sub.70 as main components. However, all other conceivable fullerenes or 
fullerene derivatives can also be used. 
The fullerenes can be obtained by preparation of fullerene black in an 
electric arc process with subsequent extraction using a nonpolar organic 
solvent (crude fullerene), as described, for example, in WO 92/09279. The 
further fine separation can be carried out by column chromatography. 
Some of the fullerenes used are also commercial products. 
The cyclopropanation reagents used can be, on the one hand, commercial 
.alpha.-halo CH acid compounds or the compounds of the formula II which 
are used can be obtained by methods known to the chemist, such as the 
halogenation of CH acid compounds or, for example, the Friedel-Crafts 
acylation of substituted aromatics using bromoacetyl halides. Ester and 
amide functions are obtained from the desired carboxylic acids and 
alcohols or amines by known methods. 
The compounds of the invention having the formula I are used, for example, 
in optoelectronic components. 
The invention is illustrated by the examples. 
Index of Abbreviations 
CDCl.sub.3 : deuterotrichloromethane 
CD.sub.2 Cl.sub.2 : dideuterodichloromethane 
CS.sub.2 : carbon disulfide 
DBU: 1,8-diazobicyclo5.4.0!undec-7-ene 
DMAP: 4-dimethylaminopyridine 
d: doublet (NMR) or day(s) (indication of time) 
Et.sub.2 O: diethyl ether 
HPLC: high-pressure liquid chromatography 
h: hours 
MS (FAB): mass spectrometry (fast atom bombardment) 
m: medium (IR) or multipier (NMR) 
NaH: sodium hydride 
q or quart: quartet (NMR) 
quint: quintet (NMR) 
R.sub.f : ratio of fronts in thin-layer chromatography 
S: singlet (NMR) or strong (IR) 
SiO.sub.2 : silica gel for chromatographic purposes 
t: triplet (NMR) 
W: weak (IR)