A [70]Fullerene Chloride, C₇₀Cl₁₆, Obtained by the Attempted Bromination of C₇₀ in TiCl₄

Abstract

The use of liquid inorganic chlorides as chlorinating agents for fullerenes resulted recently in the synthesis of several new chlorofullerenes. In addition to C 60 Cl 6 , which was obtained many years ago and investigated by 13 C NMR and IR spectroscopy, [1] four highly chlorinated [60]fullerenes, C 60 Cl 24 , [2] C 60 Cl 28 , [3] and two isomers of C 60 Cl 30 , [3,4] have been prepared and characterized by means of single-crystal X-ray crystallography and IR spectroscopy. The application of this method to the chlorination of C 70 produced a highly chlorinated fullerene, C 70 Cl 28 , which, according to the singlecrystal X-ray crystallographic study, comprised three isomers with similar structures.[5] Earlier, C 70 Cl 10 was prepared by treating C 70 with ICl in benzene; its addition pattern has been deduced from 13 C NMR spectroscopic analysis, [6a] substitution reactions, [6b] and theoretical modeling studies.[6c] Thus, the chlorination of the fullerenes under mild conditions results in "lower" chlorides, whereas the use of strong chlorinating agents at elevated temperatures produces "higher" chlorides of both [60]-and [70]fullerenes. These results raise the question as to whether "missing" intermediate chlorides could be obtained by variation of the reactants and/or reaction conditions. Herein, we report the synthesis of such an intermediate chloride of [70]fullerene, C 70 Cl 16 , and its characterization by single-crystal X-ray crystallography, IR spectroscopy, and DFT calculations. Notably, the new fullerene chloride was obtained during an attempt to brominate C 70 in TiCl 4 . Typically, neat bromine (0.5 mL) was added to a solution of C 70 (30 mg) in TiCl 4 (2.0 mL) in a glass ampoule. The ampoule was evacuated on cooling and sealed. A yellow crystalline precipitate formed after heating the mixture at 60-80 8C for 1-2 days. Work-up consisted of distilling off the bromine and excess TiCl 4 into a second section of the sealed ampoule by cooling it with liquid nitrogen. Alternatively, the ampoule was opened and the mixture was poured into 15 % HCl. The yellow precipitate so formed was washed with dilute HCl and then water before removal by filtration and drying at 50 8C for

Structure of 1,4,10,19,25,41-C70(CF3)6, isomer with unique arrangement of addends

“…Hence, although the energy criterion remains important in the selection of a range of candidate structures, possible kinetic factors governing regioselectivity of CF 3 addition need to be taken into account. One of the most simple but helpful methods to find the preferential addition sites in the stepwise radical addition reactions is based on the comparison of the free valence indexes in the closed-shell molecules and spin densities in the radical intermediates [14,15].…”

Searching for stable hept‐C62X2 (X = F, Cl, and Br): Structures and stabilities of heptagon‐containing C62 halogenated derivatives

“…They assumed the addends were attached to a fullerene framework sequentially, and the first addend should be attached to a position of maximum free‐valence, and the second addend should be attached to a position of maximum spin density. This model has been successfully applied to many systems 38–41. Herein, we first attach one addend to one of the two most active sites C(9) (the other is C(10)) to obtain hept‐C 62 X (X = F, Cl, and Br), and then check the spin densities of all atoms.…”

Relationships Between Soluble Zintl Anions, Ligand-Stabilized Cage Compounds, and Intermetalloid Clusters of Tetrel (Si–Pb) and Pentel (P–Bi) Elements

“…The resulting cluster contains a linear chain of three Ni atoms and two widely opened Ge 9 polyhedra. These two Ge 9 units have a relative orientation that allows -after subsequent intercluster Ge-Ge bond formation -the formation of the ellipsoidally shaped cluster [Pd 2 (Fig. 6h).…”

“…Bare group 14 and 15 element clusters are well investigated in the gas phase, but scarcely exist in macroscopic amounts and are limited to simple molecules such as P 4 , Sb 4 , and Bi 4 and to carbon polymorphs such as C 60 and C 70 . When ligands attached to the atoms of the homoatomic cages are tolerated, a much larger variety of group 14 and 15 element clusters with homoatomic bonds is accessible, of which tetrahedrane C 4 t Bu 4 [1], prismane, dodecahedrane, or functionalized fullerenes such as C 70 Cl 16 [2] are pertinent examples in carbon chemistry, and Si(Si are soluble in polar, organic solvents -they have a large potential as starting materials for the synthesis of larger clusters. The availability of such so-called Zintl ions in large quantity provides a much better starting position than all the improved synthetic approaches to fullerenes [11] or to group 13 element clusters [12].…”

“…Si 4 R 4 [3] Pb 10 R 6 [4] [Li + @C 60 ] [274] C 70 R 16 [2] [Al@Al 12 @Al 44 {AlR} 20 ] 2- [5] [Si 4 ] 4- [10] [Pb 10 ] 2- [13] [ The terms metalloid and intermetalloid are used according to the following definitions: The term metalloid cluster was introduced for species that contain both ligand-bearing and ligand-free metal atoms which are bonded exclusively to other metal atoms, and which contain more metal-metal than metal-ligand bonds. With respect to their topology, metalloid clusters show similarities to the respective bare elements [7].…”