A family of unsymmetrical hydroxyl-substituted BEDT-TTF donors: syntheses, structures and preliminary thin film studies

Abstract

Three new unsymmetrical hydroxyl-functionalized donors H1-H3 closely related to hydroxymethyl-BEDT-TTF have been synthesised and characterised. Cyclic voltammetry studies showed that the compounds exhibit reversible two one-electron redox processes typical for BEDT-TTF derivatives. X-ray diffraction studies of H1 and H2 reveal p-stacking interactions between pairs of donors that are organized into distinct H-bonded square motifs and DFT calculations indicate that the HOMO is located on the central 1,3-dithiole rings. Protection of the hydroxyl group with acetyl in 13 eliminates co-facial S/S interactions between the dimers to accommodate the bulkier side chains, but short edge-to-edge S/S contacts offer an alternative pathway for electron mobility. Chemical oxidation of H1 and HMET 2 with I 2 afforded single crystals of two 1 : 1 charge transfer salts, 18 and 19. The molecules pack as dimers with close p-stacking interactions between pairs of radical cations whose crystal structures are further stabilized via an interplay of S/S and S/I contacts. Iodine-doped surface conducting polystyrene blend films of H3 deposited on a silica substrate exhibit quasiconducting properties, but afford no OFET response when fabricated into devices. Visible-NIR studies of a doped polystyrene blend film of H3 cast on a glass substrate show absorption bands at l ¼ 950 and 3000 nm, consistent with mixed valence states due to the presence of charge-transfer species on the surface of the films.

Ab initio investigation of nonlinear optical, electronic, and thermodynamic properties of BEDT-TTF molecule: doping with boron

“…Much attention continues to be directed to the development of magnetic molecular conductors taking into account interactions between conductive electrons and localized spins. In this context, a global study of the vibrational dynamics of the bis(ethylenedithio) tetrathiafulvalene has been performed through ab-initio investigations [10,11,12,13,14]. These studies have contributed much to our knowledge of the vibrational spectra of these molecules.…”

Synthesis of New Derivatives of BEDT-TTF: Installation of Alkyl, Ethynyl, and Metal-Binding Side Chains and Formation of Tris(BEDT-TTF) Systems

“…4 K [20], the racemic bipyridylthiomethyl derivative 4 which forms capsular structures with metal ions [21], and the spiro chiral derivative 5 [22]. BEDT-TTF donors with one amino-methyl or -ethyl side chain [23], one hydroxy-methyl or -ethyl side chain [24,25], or with multiple hydroxymethyl or 1,2-dihydroxyethyl chains such as 6 and 7 have also been reported [26][27][28], as well as systems where the BEDT-TTF unit is fused to a thiophene or furan ring [29].…”

“…The first is via the dithiolate 8, available from carbon disulphide and sodium, by double substitutions with dihalides or cyclic sulphate esters to give the bicyclic thione 9 [16,24]. The second is via the trithione 10, which reacts with alkenes in a 4 + 2 electrocyclic reaction to also give the bicyclic thione 9 [22][23][24][25][26][27][28][30][31][32][33][34]. In both cases, the synthesis is completed by conversion of the thione to the oxo compound 11 by treatment with mercuric acetate, and then reaction with triethyl or trimethyl phosphite to form the homo-coupled BEDT-TTF system 13.…”