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Bond Orders and Atomic Properties of the Highly Deformed Halogenated Fullerenes C 60 F 18 and C 60 Cl 30 Derived from their Charge Densities
Author(s) -
Hübschle Christian B.,
Scheins Stephan,
Weber Manuela,
Luger Peter,
Wagner Armin,
Koritsánszky Tibor,
Troyanov Sergey I.,
Boltalina Olga V.,
Goldt Il'ya V.
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200601616
Subject(s) - electronegativity , fullerene , chemistry , atom (system on chip) , chemical bond , bond length , fluorine , bond order , halogen , carbon fibers , van der waals radius , endohedral fullerene , atomic radius , atomic number , single bond , bond energy , crystallography , atomic physics , molecule , materials science , van der waals force , alkyl , crystal structure , physics , organic chemistry , composite material , embedded system , composite number , computer science
The experimental charge densities of the halogenated C 60 fullerenes C 60 F 18 and C 60 Cl 30 were determined from high‐resolution X‐ray data sets measured with conventional Mo Kα radiation at 20 K for C 60 Cl 30 and with synchrotron radiation at 92 K for the fluorine compound. Bond topological and atomic properties were analyzed by using Bader's AIM theory. For the different CC bonds, which vary in lengths between 1.35 and 1.70 Å bond orders n between n =2 and significantly below n=1 were calculated from the bond topological properties at the bond critical points (BCP's). The low bond orders are seen for 5/6 bonds with each contributing carbon carrying a halogen atom. By integration over Bader's zero flux basins in the electron density gradient vector field atomic properties were also obtained. In contrast to free C 60 , in which all carbon atoms have a uniform volume of 11 Å 3 and zero charge, atomic volumes vary roughly between 5 and 10 Å 3 in the halogenated compounds. Almost zero atomic charges are also found in the Cl derivative but a charge separation up to ±0.8 e exists between C and F in C 60 F 18 due to the higher fluorine electronegativity, which is also seen in the electrostatic potential for which the electronegativity difference between carbon and fluorine, and the addition to one hemisphere of the fullerene cage leads to a strong potential gradient along the C 60 F 18 molecule. From the summation over all atomic volumes it follows that the halogen addition does not only lead to a dramatic distortion of the C 60 cage but also to a significant shrinkage of its volume.