Bw. Clare et Dl. Kepert, STEREOCHEMICAL PATTERNS IN BROMOFULLERENES C60BR2 TO C60BR12, Journal of molecular structure. Theochem, 340, 1995, pp. 125-142
The stabilities of different isomers of C60Brn have been calculated fo
r n = 2 to 12. A general stereochemical pattern which emerges is the t
endency to form strings created by the edge sharing of C6Br2 hexagonal
faces. Stable structures are formed if these strings form loops, ther
eby eliminating string ends, which may involve the creation of C6Br3 h
exagonal faces. A particularly stable structure is formed at C60Br6 in
which the loop forms a C10Br6 fragment with a pentagonal pyramidal ar
rangement of six bromine atoms. Two isomers of C60Br12 are also partic
ularly stable. One isomer contains two of these Br-6 pentagonal pyrami
ds on opposite sides of the molecule, and the ether isomer contains a
single large loop wrapped around the middle of the molecule.