title: Nonelectrochemical synthesis, crystal structure, and physical properties of the radical salt [ET]2[CuCl4] (ET = bis(ethylenedithio)tetrathiafulvalene).
abstract: The radical salt [ET]2[CuCl4] was obtained by chemical oxidation of bis(ethylenedithio)tetrathiafulvalene (ET) with the tetranuclear copper(II) halide cluster [Cu4OCl10](4-). Although a complex mixture of anions forms in solution during the redox reaction, only this product is obtained as large (>3 mm) single crystals. X-ray diffraction analysis determined that the ET molecules stack in the solid state forming dimerized 1D chains along the a axis, interleaved by [CuCl4](2-) anions. The ET dimers show very short S···S contacts (<3.41 Å). The physical properties are dominated by these intradimer ET interactions. The magnetic behavior shows antiferromagnetic coupling with a singlet-triplet gap >620 K (430 cm(-1)). The Cu(2+) (S = 1/2) centers are magnetically isolated and yield a narrow EPR line in the X-band at g = 2.01. The ET moieties are EPR silent.
authors.affiliation: Institute of Chemical Research of Catalonia (ICIQ) , Av. Paisos Catalans 16, E-43007 Tarragona, Spain.
authors.forename: Bárbara
authors.initials: B
authors.lastname: Rodríguez-García
authors.forename: Sara
authors.initials: S
authors.lastname: Goberna-Ferrón
authors.forename: Yong-Sung
authors.initials: YS
authors.lastname: Koo
authors.forename: Jordi
authors.initials: J
authors.lastname: Benet-Buchholz
authors.forename: José Ramón
authors.initials: JR
authors.lastname: Galán-Mascarós