Halogenated Benzene Cation Radicals

The benzene cation radicals [C6F5-CF3]+, [1,4-C6F4(CF3)2]+, [1,2,4,5-C6H2Cl4]+, [C6F5-C6F5]+, and [C6Br6]+ have been obtained as salts with fluoroarsenic and fluoroantimony counterions. Their structures have been obtained by single-crystal structure determinations, and supported by ESR measurements and DFT calculations. [C6F5-CF3]+, [1,4-C6F4(CF3)2]+, and [1,2,4,5-C6H2Cl4]+ have the predicted bisallyl type structure. [C6F5-C6F5]+ can be described as having a quinoid form with a strengthened central C–C bond and a smaller dihedral angle as compared to the neutral C6F5-C6F5. [C6Br6]+ is the missing link between [C6F6]+, [C6Cl6]+, and [C6I6]+. It has a Jahn–Teller distortion, though weaker than [C6F6]+ and [C6Cl6]+, in contrast to [C6I6]+, which remains in a regular hexagon structure.

[1]  J. Zuo,et al.  Synthesis, characterization, and structures of a persistent aniline radical cation. , 2012, Angewandte Chemie.

[2]  S. Strauss,et al.  Halogenated benzene cation radicals. , 2012, Chemistry.

[3]  K. Seppelt,et al.  Die zwei Strukturen des Hexafluorbenzol‐Radikalkations C6F6.+ , 2009 .

[4]  G. Sheldrick.  A short history of SHELX. , 2008, Acta crystallographica. Section A, Foundations of crystallography.

[5]  S. Lindeman,et al.  Structural characterization of quaterphenyl cation radical: X-ray crystallographic evidence of quinoidal charge delocalization in poly-p-phenylene cation radicals. , 2007, Journal of the American Chemical Society.

[6]  K. A. Padmanabhan,et al.  Isostructurality, polymorphism and mechanical properties of some hexahalogenated benzenes: the nature of halogen...halogen interactions. , 2006, Chemistry.

[7]  R. Minkwitz,et al.  Synthesis and Characterisation of New Arsonium Salts and Crystal Structures of Trimethylarsonium Undecafluorodiarsenate (CH3)3AsH+As2F11− and Trimethylarsonium Hexafluoroantimonate (CH3)3AsH+SbF6− , 1999 .

[8]  Klaus Müller-Dethlefs,et al.  Struktur und Symmetrie des Benzol‐Kations , 1993 .

[9]  A. Becke.  Density-functional thermochemistry. III. The role of exact exchange , 1993 .

[10]  J. C. Martin,et al.  The stable singlet ground state dication of hexaiodobenzene: possibly a .sigma.-delocalized dication , 1988 .

[11]  T. Richardson,et al.  THE PREPARATION AND CHARACTERIZATION OF RADICAL-CATION SALTS DERIVED FROM PERFLUOROBENZENE, PERFLUOROTOLUENE AND PERFLUORONAPHTHALENE , 1986 .

[12]  K. Nunome,et al.  E.s.r. evidence for the static distortion of 2E1g benzene cations giving 2B2g with D2h symmetry in low temperature matrices , 1983 .

[13]  K. Seki,et al.  Polarization energies of organic solids determined by ultraviolet photoelectron spectroscopy , 1981 .

[14]  T. Richardson,et al.  Salts of hexafluorobenzene cation, C6F6+ , 1974 .

[15]  N. Bartlett,et al.  Dioxygenyl salts dioxygenylhexafluoroantimonate and dioxygenylundecafluorodiantimonate and their convenient laboratory syntheses , 1973 .

[16]  V. D. Shteingarts,et al.  Polyfluoroaromatic cation radicals , 1969 .

[17]  J. Shamir,et al.  Photochemical synthesis of dioxygenyl salts , 1968 .

[18]  D. C. Frost,et al.  A Study of the Energy Levels in Benzene and Some Fluorobenzenes by Photoelectron Spectroscopy , 1967 .

[19]  F. Herbstein.  Twinned crystals. II. α-l,2:4,5-Tetrachlorobenzene , 1965 .

[20]  W. Price,et al.  The effect of fluorine on the electronic spectra and ionization potentials of molecules , 1960, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.