Preparation and properties of TTF and TSF salts with planar platinum(II) and copper(II) oxalate anions

Abstract

Tetrathiafulvalene (TTF) and tetraselenafulvalene (TSF) salts with bis(oxalato)platinate, dichloro(oxalato)platinate, and bis(oxalato)cuprate anions were prepared by the reaction of [TTF] 3[BF 4] 2 or [TSF] 3[BF 4] 2 with the oxalatometallates, either in acetonitrile or in dimethyl sulfoxide. These salts contain neutral TTF 0 or TSF 0 as well as the TTF• + or TSF• + radical cation. Electronic reflectance spectra of the salts show a band due to dimeric (TTF• +) 2 or (TSF• +) 2 in the 13100–14000 or 10500–12300 cm −1 region, as well as a band due to a TTF• +/TTF 0 or TSF• +/TSF 0 charge transfer transition in the 8600–8900 cm −1 range. X-Ray photoelectron spectra of the TTF salts with oxalato-platinates indicate the occurrence of some negative charge transfer from the TTF moiety to the platinate anion. It is also suggested that the planar bis(oxalato)cuprate anions in the TTF and TSF salts exist as a dimer based on the ESR spectra. All the salts behave as semiconductors with the electrical resistivities in the order 10 2–10 4 Ω cm as compacted samples at 25 °C.