First Radical Cation Salt of Paramagnetic Transition Metal Complex Containing TTF as Ligand, [Cu^II(hfac)₂(TTF-py)₂](PF₆)·2CH₂Cl₂ (hfac = Hexafluoroacetylacetonate and TTF-py = 4-(2-Tetrathiafulvalenyl-ethenyl)pyridine)

Abstract

The preparation, X-ray crystal structure, EPR data, and magnetic measurement of [Cu(II)(hfac)(2)(TTF-py)(2)](PF(6)).2CH(2)Cl(2), a novel material where the conducting and the localized spin systems are covalently linked through conjugated bridges, are reported. The partial oxidation of the TTF-type organic donor ligand yielded the first radical cation salt of a paramagnetic transition metal complex. Moreover, this compound shows a mixed valence state at the unimolecular level, and additionally, the arrangement of the molecules in the crystal structure revealed the presence of isolated mixed valence TTF dimers.

A Radical‐Radical and Metal–Metal Coupling Tetrathiafulvalene Derivative in which Organic Radicals Directly Coordinate to CuII Ions

“…[22] A solid-state EPR spectrum (polycrystalline sample), which strongly supports the speculation, was measured at 110 K ( Figure 5). Because the organic radicals are dimerized with very short S···S stacking and are strongly antiferromagnetically coupled no sharp radical signal is observed in the EPR spectrum.…”

“…Prior to the report of Ouahab et al, where the TTF radicals directly coordinate to the paramagnetic ions, [22] the charge transfer TTF compounds containing paramagnetic inorganic ions were radical salts in which the cations and anions are discretely arranged. The compound 1 reported here is a new example in which the TTF radicals directly coordinate to the paramagnetic ions.…”

“…The metal coordination of complexes with the TTF ligand offers a novel perspective on the modulation of the architec- 6 ]·2CH 2 Cl 2 , which has metal-radical and radicalradical couplings. [22] Besides the metal coordination, hydrogen bonds are also one of the successful strategies used to promote the properties of molecular solids. Some amidefunctionalized TTFs have been prepared and their radical salts involving N-H···Cl/O hydrogen bonds were studied.…”

Tetrathiafulvalene-based group XV ligands: Synthesis, coordination chemistry and radical cation salts

“…Its electrocrystallization in the presence of n Bu 4 NPF 6 afforded a mixed-valence salt, (Cu1) + , formulated as [Cu(hfac) 2 (14a) 2 ](PF 6 )·2CH 2 Cl 2 [137]. This represents the very first example of a complex based on a TTF ligand, where the TTF itself is oxidized to the cation radical state, and more interestingly, into an appealing mixed-valence state.…”

Towards Molecular Conductors with a Spin‐Crossover Phenomenon:Crystal Structures, Magnetic Properties and Mössbauer Spectra of[Fe(salten)Mepepy][M(dmit)2] Complexes

“…An attractive way of increasing the π-d interactions between the two networks consists of connecting them by covalent linkages. This has been attempted by Ouahab and co-workers in [Cu(hfac) 2 (TTF-py) 2 ]-(PF 6 )·2CH 2 Cl 2 [12] [hfac = hexafluoroacetylacetonate and TTF-py = 4-(2-tetrathiafulvalenylethenyl)pyridine], by connecting TTF to the Cu II complex by unsaturated bonds and rings. So far, however, this approach has led to molecular compounds with very poor conducting properties and lack of magnetic properties of interest.…”