Halogen Bonding in Conducting or Magnetic MolecularMaterials - Halogen Bonding: Fundamentals and Applications - page 180

Halogen Bonding in Conducting
or Magnetic Molecular Materials

Marc Fourmigué
Equipe Matière Condensée et Systèmes Electroactifs (MaCSE),
Sciences Chimiques de Rennes, UMR 6226 CNRS-Université Rennes 1,
Campus de Beaulieu, 35042 Rennes, France
[e-mail]

1 Introduction .................................. 182

2 Neutral Radical Nitroxides .......................... 183

2.1 HalogenatedNeutralNitroxides........................ 183

2.2 BinarySystemsInvolvingNitroxides ..................... 185

3 Conducting Materials Based on Tetrathiafulvalenes ............ 186

3.1 AnIntroductiontoConductingTTFSalts .................. 187

3.2 NeutralHalogenatedTTFs........................... 188

3.3 CationRadicalSaltsofHalogenatedTTFs .................. 192

3.3.1 Hal ··· Hal anion Interactions........................... 192

3.3.2 Hal ··· NitrileInteractions ........................... 197

3.3.3 IodopyrazinoTTFs,Iododithiapyrenes.................... 200

3.4 TernarySystems ................................ 202

4 Summary and Outlook ............................ 202

References ....................................... 204

Abstract The role of halogen bonding interactions in conducting or magnetic molecular
systems is evaluated here in various series of halogenated radical molecules, such as neu-
tral nitroxides or tetrathiafulvalene (TTF) salts where short and linear C - Hal Hal,O,N

interactions are identified. Oxidation of halogenated TTFs to the cation radical state ac-
tivates the halogen bonding interaction with counter ions of Lewis base character, i.e.
halide, polyhalide or halometallate anions on the one hand, and polycyanometallate or
organic nitrile anions on the other. Iodoperfluoroalkanes or -perfluorarenes can also act
as halogen bond donors when associated with neutral nitroxide radicals or with halide
anions in cation radical salts of non-halogenated TTFs.

···

Keywords Crystal engineering · Halogen bonding · Nitroxide · Te t r a t h i a f u l v a l e n e

Abbreviations
BEDT-TTF Bis(ethylenedithio)tetrathiafulvalene
CCDC Cambridge Crystallographic Data Centre

DIA Diiodoacetylene

DTPY 1,6-Dithiapyrene

EDO-TTF Ethylenedioxo-tetrathiafulvalene