Infrared, Raman, and DFT Vibrational Spectroscopic Studies of C60F36 and C60F48

Photoelectron spectroscopy of C60Fn- and C60Fm2- (n = 17, 33, 35, 43, 45, 47; m = 34, 46) in the gas phase and the generation and characterization of C1-C60F47- and D2-C60F44 in solution

A photoelectron spectroscopy investigation of the fluorofullerene anions C(60)F(n)(-) (n = 17, 33, 35, 43, 45, 47) and the doubly charged anions C(60)F(34)(2-) and C(60)F(46)(2-) is reported. The first electron affinities for the corresponding neutral molecules, C(60)F(n), were directly measured and were found to increase as n increased, reaching the extremely high value of 5.66 +/- 0.10 eV for C(60)F(47). Density functional calculations suggest that the experimentally observed species C(60)F(17)(-), C(60)F(35)(-), and C(60)F(47)(-) were each formed by reductive defluorination of the parent fluorofullerene, C(3v)-C(60)F(18), C(60)F(36) (a mixture of isomers), and D(3)-C(60)F(48), respectively, without rearrangement of the remaining fluorine atoms. The DFT-predicted stability of C(60)F(47)(-) was verified by its generation by chemical reduction from D(3)-C(60)F(48) in chloroform solution at 25 degrees C and its characterization by mass spectrometry and (19)F NMR spectroscopy. Further reductive defluorination of C(60)F(47)(-) in solution resulted in the selective generation of a new fluorofullerene, D(2)-C(60)F(44), which was also characterized by mass spectrometry and (19)F NMR spectroscopy.

Effect of curvature on C-F bonding in fluorinated carbons: from fullerene and derivatives to graphite

The effect of the curvature of the carbon lattice is discussed taking into account NMR data on various fluorinated carbons including C(60) fullerenes, single, double and multiwall carbon nanotubes. Graphite fluorides and highly fluorinated fullerenes are used as limit model compounds for planar and spherical geometries, respectively. The curvature results in a weakening of the C-F bonding covalence. First of all, various highly fluorinated fullerenes with increasing F/C molar ratio were prepared by treatment with pure gaseous fluorine. A preliminary study using XRD, EPR and IR spectroscopy confirms that the highest fluorination level can be reached either at 133 or at 300 degrees C. In order to extract the correlation between fluorine and carbon atoms and the C-F bond length, specific sequences such as solid echo, two-dimensional (19)F -->(13)C cross polarization wide-line separation and inverse (19)F -->(13)C cross polarization were also used for fluorinated C(60).