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Novel coordination polymers embedding electroactive moieties present a high interest in the development of porous conducting materials. While tetrathiafulvalene (TTF) based metal‐organic frameworks were reported to yield through‐space conducting frameworks, the use of S‐enriched scaffolds remains elusive in this field. Herein is reported the employment of bis(vinylenedithio)‐tetrathiafulvalene (BVDT‐TTF) functionalized with pyridine coordinating moieties in coordination polymers. Its combination with various transition metals yielded four isostructural networks, whose conductivity increased upon chemical oxidation with iodine. The oxidation was confirmed in a single‐crystal to single‐crystal X‐ray diffraction experiment for the Cd(II) coordination polymer. Raman spectroscopy measurements and DFT calculations confirmed the oxidation state of the bulk materials, and band structure calculations assessed the ground state as an electronically localized antiferromagnetic state, while the conduction occurs in a 2D manner. These results are shedding light to comprehend how to improve through‐space conductivity thanks to sulfur enriched ligands. [ABSTRACT FROM AUTHOR]

An enlarged version of the ubiquitous tetrathiafulvalene-tetrabenzoic acid is described, with 4,4′-biphenyl moieties as spacers between the coordination moieties and the electroactive core. The obtained rectangular ligand has a 14 × 22 Å2 size and is combined with Zn(II) under solvothermal conditions to yield a coordination polymer endowed with large cavities of ca. 15 × 11 Å2/10 × 10 Å2. The topology of the material is discussed in detail using the Points of Extension and Metals (PE&M) or the Straight-rod (STR) representation, and the sqc1121 or tfo topological type of the structure is observed, respectively. Its stability towards solvent removal and electrical properties are discussed. The material does not present any permanent porosity upon desolvation according to nitrogen sorption measurements at 77 K. Nevertheless, a significant increase in conductivity is observed on compressed pellets of the material upon post-synthetic oxidation with iodine. Raman spectroscopy combined with density functional theory (DFT) calculations has been used to characterize the oxidation state of tetrakis(4-carboxylic acid biphenyl)tetrathiafulvalene for coordination polymers. [ABSTRACT FROM AUTHOR]

Control of the structural type in metallic enantiopure and racemic radical cation salts is achieved through hydrogen bonding interactions between the chiral donor DM-EDT-TTF and the XF6 anions (X = P, As, Sb), determined by the anion size and the chiral information. [ABSTRACT FROM AUTHOR]

In the presence of MeI or EtI, N-tert-butyl-1,3-thiazoline-2-thione derivatives undergo a transformation to 2-alkylthio-thiazoledithiolate pro-ligands with elimination of the tert-butyl substituent. The corresponding AuIII dithiolene complexes [Au(RS-tzdt)2]− (R = Me, Et) oxidize readily to the neutral radical species, such as the semi-conducting [Au(EtS-tzdt)2]Ṗ, which organizes into dimers in the solid state. [ABSTRACT FROM AUTHOR]

Enantiopure (S,S) and (R,R) dimethyl-ethylenedithio-tetrathiafulvalene (DM-EDT-TTF) 1 donors are synthesized by cross coupling followed by decarboxylation reactions. In the solid state the methyl groups are arranged in axial positions within sofa-type conformation for the six-membered rings. Crystalline radical cation salts formulated as [(S,S)-1]2PF6, [(R,R)-1]2PF6, and [(rac)-1]2PF6 are obtained by electrocrystallization. When the experiment is conducted with enantioenriched mixtures both enantiopure and racemic phases are obtained. The monoclinic enantiopure salts, containing four independent donors in the unit cell, show semiconducting behavior supported by band structure calculations of extended Hückel type. The racemic salt contains only one independent donor in the mixed valence oxidation state +0.5. Under ambient pressure the racemic material is metallic down to 120 K, while an applied pressure of 11.5 kbar completely suppresses the metal-insulator transition. Band structure calculations yield an open Fermi surface, typical for a pseudo-one-dimensional metal, with unperfected nesting, thus ruling out the possibility of charge or spin density modulations to be at the origin of the transition. Raman spectroscopy measurements, in agreement with structural analysis at 100 K, show no indication of low-temperature charge ordering in the racemic material at ambient pressure, thus suggesting Mott-type charge localization for the observed metal-insulator transition. [ABSTRACT FROM AUTHOR]

The electrocrystallization of diiodo- and dibromo-ethylenedithiotetrathiafuvalene (EDT-TTFI[sub2] and EDT-TTFBr[sub2]) in the presence of the polymeric 1D [Et[sub4]N][Cd(SCN)[sub3]] as an electrolyte affords two different salts, formulated as [EDT-TTF-I[sub2]][sub4][Cd[sub3](NCS)[sub8]] • CH3CN H[sub2]O (1) and [EDT-TTF-Br[sub2]][sub10][Cd[sub5](SCN)[sub14]] • 2TCE (2), characterized by a two- dimensional segregation of the partially oxidized donor molecules and the polymeric anionic network incorporating embedded solvent molecules. Both salts exhibit a partial charge transfer, that is, p = 0.5 in 1 and an unconventional p = 0.4 in 2. They behave as semiconductors with σ[subRT] = 0.67 and 33 S cm[sup-1] and activation energies of 330 and 370 K for 1 and 2, respectively. Compared with a 1:3 Cd/SCN ratio of the starting electrolyte, the reconstructed, thiocyanate (SCN)-deficient motifs [Cd[sub3](NCS)[sub8]][sub2] and [Cd[sub5](SCN)[sub14]][sub4] organize into layered hollow structures with cavities filled by solvent molecules, halogen-bonded to the halogenated TTF molecules, through a C[subTTF]—N≡C—CH[sub3] interaction in 1, through a type II C[subTTF]—Br⋯CI-CTCE halogen/halogen interaction in 2. Band structure and Fermi surface calculations for the two salts indicate a two-dimensional character, while the semiconducting properties of the salts are attributed to an efficient nesting of the hidden 1D Fermi surfaces. [ABSTRACT FROM AUTHOR]

Chiral bis(TTF) diamides have been obtained in good yields (54–74%) from 1,2-cyclohexane-diamine and the corresponding TTF acyl chlorides. The (R,R)-1 and (S,S)-1 enantiomers have been characterized by circular dichroism and the racemic form by single-crystal X-ray diffraction. The neutral racemic bis(TTF)-diamide shows the formation of a pincer-like framework in the solid state, thanks to the intramolecular S···S interactions. The chemical oxidation in a solution using FeCl3 provides stable oxidized species, while the electrocrystallization experiments provided radical cation salts. In particular, single-crystal resistivity measurements on the racemic donor with AsF6− as a counterion demonstrate semiconductor behavior in this material. The DFT and TD-DFT calculations support the structural and chiroptical features of these new chiral TTF donors. [ABSTRACT FROM AUTHOR]

Abstract: The 1D organic salt TTF[Ni(dmit)2]2 becomes superconductor with T c=1.6K under an applied hydrostatic pressure of 7kbar. Structural determinations in this system lead us to suspect that superconductivity (SC) coexists with a charge density wave (CDW) instability at low pressure. In order to better understand how SC emerge from a CDW and to revisit the pressure–temperature phase diagram of the TTF[Ni(dmit)2]2 we performed transport and thermoelectric power measurements under pressure. [Copyright &y& Elsevier]

Within this work we have investigated spiro‐based tetrathiafulvalenes (TTFs) obtained as mixtures of stereoisomers from racemic spiro[5.5]undeca‐1,8‐dien‐3‐one. Compared to previously described spiro‐TTFs, enantiomeric and diastereoisomeric forms have been here separated by chiral HPLC and fully characterized both experimentally and theoretically. The two types of spiro‐based chiral derivatives contain either one (2) or three (1) chiral centres out of each one is spiro‐type. Experimental CD, supported by TD‐DFT calculations, shows differences in the optical activity between the 1 and 2 and their intermediates. The low optical activity of 2 and 3 (spiro alone chirality) was attributed to the presence of two conformers in the solution (ax and eq) of opposite Cotton effect whereas in the case of 1 and 5 (spiro and stereogenic centres) the spiro chirality seems to be responsible of the Cotton effect in the high energy region whereas the R and S chirality in the low energy region. Racemic and enantiopure forms have been successfully used for the synthesis of charge transfer complexes with tetracyanoquinodimethane (TCNQ) based acceptors. [ABSTRACT FROM AUTHOR]

Harnessing a bis(selenomethyl)tetrathiafulvalene (TTF) derivative as a donor, conducting charge transfer (CT) salts are realized thanks to original packing structures supported by chalcogen bonding (ChB) interactions. Specifically, reaction of EDT-TTF(SeMe)2 (EDT = ethylenedithio) with an acceptor, 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane (F2TCNQ), afforded two polymorphs of 1 : 1 CT salts, α- and β-[EDT-TTF(SeMe)2](F2TCNQ). The donor and the acceptor molecules in both polymorphs organize into segregated and uniform stacks. Based on the structure, the α-salt shows a quasi-complete CT while the β-salt shows a partial CT with ρ ∼±0.8. The oxidation of TTF activates the σ-hole on Se atoms to be engaged in highly linear ChB interactions with the N atoms on F2TCNQ. The formation of directional ChB interactions resulted in original packing structures of the donor and the acceptor stacks that are distinct between α- and β-salts. In particular, the ChB motif observed in the β-salt allows F2TCNQ molecules within the stack to be closer than those in the α-salt. Consequently, the α-salt is a semi-conductor, while the β-salt shows metallic behaviour with a two-step metal-to-insulator (MI) transition. Moreover, the observed MI transition temperature in the β-salt (180 K) is substantially higher than that in other known CT salts, likely owing to the 3D coupling of the modulation in different chains brought about by the –SeMe substituents. [ABSTRACT FROM AUTHOR]

In the search for single component conductors, eventually blessed with chirality, we have prepared three novel Au(iii) bis(dithiolene) complexes of the 6,7-dihydro-5H-1,4-dithiepine-2,3-bis(thiolate) ligand exhibiting a fused seven-membered ring. The unsubstituted ligand as well as two chiral enantiopure derivatives, with methyl groups in 5,7 positions or a ketal moiety in 6 position, were used to provide the corresponding anionic d8 Au(iii) bis(dithiolene) complexes (1, 2 and 3) as Bu4N+ salts. The anions adopt a square planar geometry around the gold atom with a pseudo centrosymmetric chair conformation of the outer seven-membered rings. Cyclic voltammetry experiments demonstrate that they can be easily oxidized to the neutral radical state in a 0.40–0.50 V range (vs. SCE). Their electrocrystallization afforded neutral radical species for two of them, which were structurally characterized. An original transformation of the unsubstituted complex 1 upon oxidation is observed in its oxidation product, leading to an unexpected radical complex 1′′, with two different dithiolene ligands. Its peculiar electronic structure and the formation of alternated stacks in the solid state explains its semiconducting character with direct gap. On the other hand, the radical complex 3′ derived from the chiral ketal derivative 3 is organized into face-to-face dimers, isolated from each other in the crystal. [ABSTRACT FROM AUTHOR]

The first examples of chiral single component conductors are reported. Both (S,S) and (R,R) enantiomers of 5,6-dimethyl-5,6-dihydro-1,4-dithiin-2,3-dithiolate (dm-dddt) ligand have been used to prepare anionic metal bis(dithiolene) complexes formulated as ([(n-Bu)4N][M(dm-dddt)2] (M = Au, Ni), which are isostructural according to single crystal X-ray analysis. Single crystal transport measurements indicate semiconducting behavior for the anionic radical Ni complexes, with low room temperature conductivity values and high activation energies. Electrocrystallization experiments provided neutral [M(dm-dddt) 2] (M = Au, Ni) complexes. The neutral radical gold compounds show intermolecular S...S interactions in the solid state giving rise to layers interconnected through weak C-H...S hydrogen bonds. The most peculiar structural feature concerns a dissymmetry between the two dithiolene moieties, while the nickel counterpart is symmetric. Single crystal resistivity measurements show thermally activated behavior for the open-shell gold complexes, with room temperature conductivity values of 0.02-0.04 S⋅cm-1 and activation energies strongly influenced by hydrostatic pressure. A thorough theoretical study on nickel anion radical and gold neutral radical bis(dithiolene) complexes applied to the chiral complexes [M(dm-dddt)2] (M = Au, Ni-) and to a series of previously reported compounds addressed the issue of symmetry versus asymmetry from an electronic coupling perspective between the two dithiolene ligands. It results that neutral gold complexes with dithiolene ligands without extended delocalization are Class II mixed-valent compounds in the Robin and Day classification, presenting an inherent tendency toward asymmetric structures, which can be however modulated by the intermolecular organization in the solid state. [ABSTRACT FROM AUTHOR]

Chalcogen bonding (ChB) interactions are investigated in two new –SeMe substituted tetrathiafulvalene (TTF) derivatives, RTTF(SeMe)2 (R = Me2, SCH2CH2S). Upon oxidation to 1 : 1 cationic radical salts, Se atoms are engaged in highly linear ChB interactions with bromide anions, demonstrating the efficient σ-hole activation of selenium through redox-active substituents. [ABSTRACT FROM AUTHOR]

The Z and E isomers of the iodinated TTF derivative (Z,E)-Me2I2-TTF co-crystallize in a mixed-valence salt with Br− anions, and are segregated into Z and E stacks, each of them with a different charge localization pattern, which also revealed charge-assisted halogen bonding. [ABSTRACT FROM AUTHOR]

Electrocrystallization of enantiopure (S,S,S,S)- and (R,R,R,R)-tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) donors, as well as the racemic mixture, in the presence of potassium cations and the tris(chloranilato)ferrate(III) [Fe(Cl2An)3]3- paramagnetic anion afforded a complete series of chiral magnetic molecular conductors formulated as β-[(S,S,S,S)-TM-BEDT-TTF]3PPh4[KIFeIII(Cl2An)3]·3H2O (1), β-[(R,R,R,R)-TM-BEDT-TTF]3PPh4[KIFeIII(Cl2An)3]·3H2O (2), and β-[(rac)-TM-BEDT-TTF]3PPh4[KIFeIII(Cl2An)3]·3H2O (3). Compounds 1-3 are isostructural and crystallize in triclinic space groups (P1 for 1 and 2, P-1 for 3) showing a segregated organic-inorganic crystal structure, where anionic honeycomb layers obtained by self-assembling of the Λ and Δ enantiomers of the paramagnetic complex with potassium cations alternate with organic layers where the chiral donors are arranged in the β packing motif. Compounds 1-3 show a molecular packing strongly influenced by the topology of the inorganic layers and behave as molecular semiconductors with room-temperature conductivity values of ca. 3 × 10-4 S cm-1. The magnetic properties are dominated by the paramagnetic S = 5/2 [Fe(Cl2An)3]3- anions whose high-spin character is confirmed by magnetic susceptibility measurements. The correlation between crystal structure and conducting behavior has been studied by means of tight-binding band structure calculations which support the observed conducting properties. [ABSTRACT FROM AUTHOR]

The enantiopure radical cation salts [( S, S)-DM-BEDT-TTF]4[ReCl6] ([( S, S)- 1]4[ReCl6]) and [( R, R)-DM-BEDT-TTF]4[ReCl6] ([( R, R)- 1]4[ReCl6]) [DM-BEDT-TTF = dimethylbis(ethylenedithio)tetrathiafulvalene] have been prepared by electrocrystallization of the chiral precursor DM-BEDT-TTF in the presence of NBu4[ReCl5(pyrazine)] (NBu4 = tetra- n-butylammonium cation; pyz = pyrazine) as supporting electrolyte. The single-crystal X-ray analysis shows that the compounds crystallize in the triclinic system, non-centrosymmetric space group P1, and that the donors arrange in parallel columns. The four independent donor molecules possess approximate charges of +1, +1/2, +1/2 and 0, according to the structural parameter analysis and band-structure calculations, which also support the semiconducting behaviour of the materials. The rhenium(IV) ion in both compounds is six-coordinate with six chloro atoms that describe a slightly distorted octahedral environment with Re-Cl distances that cover the short range 2.348-2.374 Å. Magnetic measurements on polycrystalline samples of [( S, S)- 1]4[ReCl6] and [( R, R)- 1]4[ReCl6] have been investigated in the temperature range 2-295 K. They are practically identical and confirm the presence of high-spin S = 3/2 [ReCl6]2- isolated monomers together with a Pauli paramagnetism, typical of this kind of system. The magnetic susceptibility data are thoroughly reproduced over the whole temperature range with a simple model of isolated S = 3/2 ions with a zero-field splitting plus a temperature-independent paramagnetism (TIP), and the best-fit parameters being gRe = 1.875(2), | D| = 4.50(3) cm-1 and TIP = 3630(20)×10-6 cm3 mol-1 (2 D is the energy gap between the MS = ±3/2 and MS = ±1/2 Kramers doublets). [ABSTRACT FROM AUTHOR]

The anionic hydroxyethyl-substituted gold dithiolene complex [NEt4] [Au(EtOH-thiazdt)2] is synthesized and further oxidized to the neutral radical species [Au(EtOH-thiazdt)2] through electrocrystallization. Single-crystal X- ray diffraction studies highlight the existence of the two cis and trans isomers for the monoanionic complex, with involvement of the hydroxy group in intermolecular O-H...S hydrogen-bonding interactions. The neutral radical complex, [Au(EtOH- thiazdt)2]*, is isostructural with its k n own ethyl analogue, namely, [Au(Et- thiazdt)2]* .It exhibits a semiconducting behavior (σRT = 0.050.07 S cm -1) at room temperature and ambient pressure with an activation energy of 0.14 eV. Comparison of the crystal structure s and transport and magnetic properties with those of the prototypical [Au (Et-thiazdt)2]* single-component conductor shows that the replacement of ethyl by a slightly bulkier hydroxyethyl substituent affects only weakly the overlap interactions, complemented here by added O-H...S hydrogen-bonding interactions. [ABSTRACT FROM AUTHOR]

Electrocrystallization of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) in the presence of the tris(chloranilato)ferrate(III) [Fe(Cl2An)3]3- paramagnetic chiral anion in different stoichiometric ratios and solvent mixtures afforded three different hybrid systems formulated as [BEDT-TTF]3[Fe(Cl2An)3]·3CH2Cl2·H2O (1), δ-[BEDT-TTF]5[Fe(Cl2An)3]·4H2O (2), and ɑ?-[BEDT-TTF]18[Fe(Cl2An)3]3·3CH2Cl2·6H2O (3). Compound 1 presents an unusual structure without the typical alternating organic and inorganic layers, whereas compounds 2 and 3 show a segregated organic-inorganic crystal structure where layers formed by Λ and δ enantiomers of the paramagnetic complex, together with dicationic BEDT-TTF dimers, alternate with layers where the donor molecules are arranged in the δ (2) and ɑ? (3) packing motifs. Compound 1 behaves as a semiconductor with a much lower conductivity due to the not-layered structure and strong dimerization between the fully oxidized donors, whereas 2 and 3 show semiconducting behaviors with high room-temperature conductivities of ca. 2 S cm-1 and 8 S cm-1, respectively. The magnetic properties are dominated by the paramagnetic S = 5/2 [Fe(Cl2An)3]3- anions whose high-spin character is confirmed by electron paramagnetic resonance and magnetic susceptibility measurements. The correlation between crystal structure and conductivity behavior was studied by means of tight-binding band structure calculations, which support the observed conducting properties. [ABSTRACT FROM AUTHOR]

Conducting and chira] [Ni(dmit)2] dithiolene salts were obtained by electrocrystallization of the radical [n-BU4N] [Ni(dmit)2] salt in the presence of chiral, enantiopure trimethylaiumonium cations. Three different cations were investigated, namely, (R)-Ph(Me)HC*-NMe3*, (S)-('Bu)- (Me)HC*-NMe3+, and (S)-(1-Napht)MeHC*-NMe3*, noted (R)-l, (S)-2, and (S)-3. Salts of 1:3 stoichiometry were obtained with (R)-l and (S)-2, formulated as [(R)-1] [Ni(dmit)2]3 and [(S)-2][Ni(dmit)2]3-(CH;,CN)2, They both crystallize in the P2i2j2i chiral space gi'oup, with three crystallographically independent complexes exhibiting different oxidation degrees. Another salt with 2:5 stoichiometry was isolated with (S)-3. The semiconducting character of the three salts (σRT - 20--30 X 10-3 S cm-1) finds its origin in a stiong electron localization, favored by the large number of crystallographically independent [Ni(dmit)2] complexes in these chiral structures and their association into wealdy interacting dimeric or trimeric motifs. Racemic salts with the same cations, obtained only with difficulties witli the íerí-butyl-containing (rac)-2 cation, afforded similar trimerized structures. The observed unusual stoicliiometry and stiong charge localization is tentatively assigned to the size and anisotiopic charge distribution of the cations. [ABSTRACT FROM AUTHOR]

The formation of (TMTSF)2ClO4 (tetramethyltetraselenafulvalene (TMTSF)) superconducting films on (TMTSF)2PF6 single-crystal templates is found to be strongly solvent dependent. Striking differences are observed by scanning electron microscopy in the structures of (TMTSF)2ClO4 coatings obtained by immersion in tetrahydrofuran, toluene, ethanol, 1,1,1-trichloroethane and 1,1,2-trichloroethane electrolyte solutions. However, the solubilities of the bulk (TMTSF)2PF6 and (TMTSF)2ClO4 materials in the considered media do not account for the observed surface modifications. [Copyright &y& Elsevier]

A chiral organic conductor with metallic conductivity has been obtained by electrocrystallisation of a diiodotetrathiafulvalene derivative and enantiopure D-camphorsulfonate anion, associated in the solid state by halogen bonding interactions. [ABSTRACT FROM AUTHOR]

Electrocrystallization of TMTTF (tetramethyltetrathiafulvalene) in the presence of the dianionic [Pt(qS)2]2− platinum complex (qS: 5-sulfo-8-quinolinol) afforded simultaneously two phases. Phase A with isolated dicationic (TMTTF)22+ species is fully insulating and characterized by C–H hydrogen bonds with the anionic sulfonate moieties. Phase B is a mixed valence salt formulated as (TMTTF)3[Pt(qS)2]. It is organized into strongly trimerized chains, with a notably higher conductivity (σRT = 4 × 10−5 S cm−1). The charge distribution within the TMTTF trimers has been evaluated from the intramolecular bond distances, and IR and Raman spectra, converging all to a +0.5/+1/+0.5 motif, which is not modified at lower temperatures. Spectroscopic studies of such trimeric structures are scarce and the doublet (or triplet) structure expected in the IR of trimers is clearly identified here in the EMV-activated ν8(ag) mode associated with the totally symmetric vibration of methyl groups, in relation to the weak C–H⋯O hydrogen bonds between the radical cation and the dianionic [Pt(qS)2]2− platinum complex. [ABSTRACT FROM AUTHOR]

Molecular metals have been essentially obtained with tetrathiafulvalene (TTF)-based precursors, either with multicomponent ionic materials or, in a few instances, with single-component systems. In that respect, gold bis- (dithiolene) complexes, in their neutral radical state, provide a prototype platform toward such single-component conductors. Herein we report the first single-component molecular metal under ambient pressure derived from such Au complexes without any TTF backbone. This complex exhibits a conductivity of 750 S-cm-1 at 300 K up to 3800 S-cm-1 at 4 K. First-principles electronic structure calculations show that the striking stability of the metallic state finds its origin in sizable internal electron transfer from the SOMO-1 to the SOMO of the complex as well as in substantial interstack and interlayer interactions. [ABSTRACT FROM AUTHOR]

Neutral nickel bis(dithiolene) complexes, because of their closed-shell character, are usually considered as insulating materials, unless they are formed out of highly delocalized tetrathiafulvalenedithiolate ligands. We describe here an original series of S-alkyl substituted neutral bis(thiazole-4,5-dithiolate) nickel complexes formulated as [Ni(RS-tzdt)2] (R = Me, Et), which organize in the solid state into uniform stacks and exhibit semiconducting behavior, with room temperature conductivities comparable to those reported in the prototypical [Ni(dmit)2] and [Ni(Et-thiazdt)2] neutral complexes. These findings provide new perspectives in the current search for single component molecular conductors. [ABSTRACT FROM AUTHOR]

Among single component molecular conductors, neutral radical gold dithiolene complexes [(R-thiazdt)2Au]. derived from the N-alkyl-1,3-thiazoline-2-thione-4,5-dithiolate (R-thiazdt) ligand provide an extensive series of conducting, non-dimerized, half-filled band systems. Analogues of the known R=isopropyl ( iPr) derivative were investigated here with R=NMe2, cyclopropyl (cPr) and n-propyl ( nPr), aiming at rationalizing the different solid state structures adopted by these compounds despite very closely related substituents on the heterocyclic nitrogen atom. An original crisscross organization within dimerized chains is observed with R=NMe2, differing however from the analogous iPr derivative by a 180° rotation of the heterocyclic nitrogen substituent. On the other hand, the cyclopropyl and n-propyl substituents lead to robust, uniform, non-dimerized chains with a strongly 1 D electronic structure and a formal half-filled electronic structure. The semiconducting behaviour of these two radical complexes is characteristic of a Mott insulator, whose sensitivity to external pressure has been evaluated up to 2.5 GPa. [ABSTRACT FROM AUTHOR]

A novel 1D hybrid salt (MQ)[CuBr2]∞ (MQ = N-methylquinoxalinium) is reported. Structural, spectroscopic and magnetic investigations reveal a minimal CuII doping of less than 0.1%. However it is not possible to distinguish CuI and CuII. The unusually close packing of the organic moieties and the dark brown colour of the crystals suggest a defect electronic structure. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue is the group of Narcis Avarvari (CIMI team) at the Laboratory MOLTECH-Anjou, UMR 6200 CNRS - Université d'Angers, France. The cover image shows the enantiopure tetrathiafulvalene precursors used for the preparation of chiral radical cation conducting salts, together with an artwork of their packing diagrams and the suggested mirror image relationship between them. [ABSTRACT FROM AUTHOR]

The cover picture shows the mirror‐image relationship, like that between the two hands in the background, between two enantiopure dimethylbis(ethylenedithio)tetrathiafulvalene (DM‐BEDT‐TTF) precursors. Also shown are the solid‐state packing diagrams, represented in an artistic manner, of the mixed‐valence radical cation salts of these precursors with the hexachlororhenate(IV) dianion. These paramagnetic semiconducting chiral materials have been obtained by electrocrystallization, and their transport properties were determined by single‐crystal resistivity measurements, supported by band‐structure calculations. The organic/inorganic segregation shown in the picture is an important prerequisite for extensive electron delocalization, although charge localization occurs here in the donors. Details are discussed in the article by N. Avarvari et al. on p. 3855 ff. For more on the story behind the cover research, see the Cover Profile. [ABSTRACT FROM AUTHOR]

A complete series of dianionic, monoanionic, and neutral dithiolene complexes formulated as [Ni(Et-thiazdt)2]n, with n = -2, -1, 0, and Et-thiazdt: N-ethyl-1,3-thiazoline-2-thione-4,5-dithiolate, is prepared using an optimized procedure described earlier for the N-Me derivatives. Electrochemical and spectroscopic properties confirm the electron-rich character of the Et-thiazdt dithiolate ligand. The three complexes are structurally characterized by single-crystal X-ray diffraction. The paramagnetic anionic complex [Ni(Et-thiazdt)2]-1, as Ph4P+ salt, exhibits side-by-side lateral interactions leading to a Heisenberg spin chain behavior. The solid-state structure of the neutral, diamagnetic [Ni(Et-thiazdt)2]0 complex shows a face-to-face organization with a large longitudinal shift, at variance with the structure of its radical and neutral gold dithiolene analogue described earlier and formulated as [Au(Et-thiazdt)2]. Comparison of the two structures, and those of the other few structurally characterized pairs of Ni/Au dithiolene complexes, demonstrates the important role played by overlap interactions between gold dithiolene radical species. Despite its closed-shell character, the neutral nickel complex [Ni(Et-thiazdt)2]0 exhibits a semiconducting behavior with a room-temperature conductivity σRT ≈ 0.014 S cm-1. [ABSTRACT FROM AUTHOR]

The single crystal X-ray structure of the all-axial conformer of the (R,R,R,R) enantiomer of the chiral donor tetramethyl-BEDT-TTF (TM-BEDT-TTF) was described and compared to the all-equatorial conformer. (S,S,S,S)-Tetramethyl-BEDT-TTF formed crystalline 1:1 complexes with TCNQ and TCNQ-F4, as well as a THF solvate of the TCNQ complex. Donors bis((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene and (ethylenedithio)((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene, which contain seven-membered rings bearing chirally oriented methyl groups, only formed complexes with TCNQ-F4. The TCNQ-F4 complexes contain planar organosulfur systems, in contrast to the TCNQ complexes in which there is minimal charge transfer. A variety of crystal packing modes were observed. Electrocrystallization experiments with both enantiomers and the racemic form of tetramethyl-BEDT-TTF afforded mixed valence radical cation salts with the AsF6 and SbF6 anions formulated as (TM-BEDT-TTF)2XF6 (X = As, Sb). Electrical conductivity was only found in one charge transfer complex, while the radical cation salts are all semiconducting. [ABSTRACT FROM AUTHOR]

A mixed-valence salt of tTTF-I with ClO4 -, formulated as (tTTF-I)2ClO4, is characterized by the presence of two crystallographically independent donor molecules, segregated in different layers and linked together through I...O interactions with the ClO4 - anion disordered at room temperature. The tTTF-I donor molecule was prepared by metallation of tTTF (trimethylene tetrathiafulvalene) followed by reaction with iodine to afford the mono and diiodo derivatives tTTF-I and tTTFI2, respectively. The crystal structure of the latter neutral tTTFI2 shows the occurrence of strong type II, I...I halogen bond interactions. Band structure calculations of the dual-layer structure of the 2 : 1 salt (tTTF-I)2ClO4 show co-existence of both 1D open and 2D closed Fermi surfaces. The salt undergoes a metal-insulator phase transition at TMI = 90 K, associated with an electronic dimensionality decrease, since already at 100 K, the 2D part of the Fermi surface transforms into 1D corrugated planes. High resolution X-ray investigations performed at 100 K, combined with multipolar refinements, indicate an approximately equivalent +0.5e charge in both donor molecules, as also deduced from the intramolecular bond distances. On the other hand, Raman spectroscopic investigations show that at ambient temperature the charge is actually distributed non-uniformly in conducting layers of tTTF-I molecules, with the identification of molecules with charges +1, +0.5, 0e, while at low temperature the charge distribution becomes essentially uniform (+0.5e), as confirmed from the X-ray high resolution data. These apparently contradictory behaviors are actually a consequence of a partial electron transfer between the two independent slabs to reach a common Fermi level in the metallic phase. [ABSTRACT FROM AUTHOR]

Oxidation of diiodoethylenedithiotetrathiafulvalene (EDT-TTF-I2), C8H4I2S6, with the strong oxidizer tetrafluorotetracyanoquinodimethane (TCNQF4), C12F4N4, affords, depending on the crystallization solvent, two polymorphs of the 2:1 charge-transfer salt (EDT-TTF-I2)2(TCNQF4), represented as D2A. In both salts, the TCNQF2 is reduced to the radical anion state, and is associated through short C-I. . .NC halogen bonds to two EDT-TTF-I2 molecules. The two polymorphs differ in the solid-state association of these trimeric D-A-D motifs. In polymorph (I) the trimeric motif is located on an inversion centre, and hence both EDT-TTF-I2 molecules have +0.5 charge. Together with segregation of the TTF and TCNQ derivatives into stacks, this leads to a chargetransfer salt with high conductivity. In polymorph (II) two crystallographically independent EDT-TTF-I2 molecules bear different charges, close to 0 and +1, as deduced from an established correlation between intramolecular bond lengths and charge. Overlap interactions between the halogen-bonded D0-A-•-D+• motifs give rise, in a perpendicular direction, to diamagnetic A22- and D0-D22+-D0 entities, where the radical species are paired into the bonding combination of respectively the acceptor LUMOs and donor HOMOs. The strikingly different solid-state organization of the halogen-bonded D- A-D motifs provides an illustrative example of two modes of face-to-face interaction between π-type radicals, into either delocalized, uniform chains with partial charge transfer and conducting behaviour, or localized association of radicals into face-to-face A22- and D22+ dyads. [ABSTRACT FROM AUTHOR]

The sensitivity of electronic propertiesof organic conductorsto minute modifications of their solid-state structure is investigatedhere within BEDT-TTF (ET) salts with organic bis-sulfonate anions,where specific hydrogen bonds between water molecules and sulfonatemoieties are shown to dynamically control the organic slabs’electronic structure. While the mixed-valence, 2,6-naphthalene-bis(sulfonate)salt, (ET)4(NBS)·4H2O, exhibitsa charge order state already at room temperature, the correspondingsalt with the 2,6-anthracene-bis(sulfonate) dianion, formulated as(ET)4(ABS)·4H2O, is metallicat RT and exhibits a metal–insulator transition at TMI= 85 K. The origin of the MI transition isrevealed from a combination of temperature-dependent spectroscopic(Raman) measurements, X-ray structure elucidations (from 300 to 15K), and theoretical investigations, demonstrating that the chargedisproportionation observed below TMIisassociated here with the progressive switching of bifurcated OH···Ohydrogen bonds between the sulfonate moieties of the anion and thetrapped water molecules. These movements within the anion layer aretransmitted through weaker C–H···O interactionsto the two A and B donor molecules, modifying the details of the overlapinteractions within AA and BB pairs and opening a gap in the bandstructure. [ABSTRACT FROM AUTHOR]

Charge-assisted halogen bonding is unambiguously revealed from structural and electronic investigations of a series of isostructural charge-transfer complexes derived from iodinated tetrathiafulvalene and tetracyanoquinodimethane derivatives, (EDT-TTFI2)2(TCNQF n), n=0-2, which exhibit variable degrees of ionicity. The iodinated tetrathiafulvalene derivative, EDT-TTFI2, associates with tetracyanoquinodimethane (TCNQ) and its derivatives of increasing reduction potential (TCNQF, TCNQF2) through highly directional CI⋅⋅⋅N≡C halogen-bond interactions. With the less oxidizing TCNQ acceptor, a neutral and insulating charge-transfer complex is isolated whereas with the more oxidizing TCNQF2 acceptor, an ionic, highly conducting charge-transfer salt is found, both of 2:1 stoichiometry and isostructural with the intermediate TCNQF complex, in which a neutral-ionic conversion takes place upon cooling. A correlation between the degree of charge transfer and the CI⋅⋅⋅N≡C halogen-bond strength is established from the comparison of the structures of the three isostructural complexes at temperatures from 300 to 20 K, thus demonstrating the importance of electrostatics in the halogen-bonding interaction. The neutral-ionic conversion in (EDT-TTFI2)2(TCNQF) is further investigated through the temperature dependence of its magnetic susceptibility and the stretching modes of the C≡N groups. [ABSTRACT FROM AUTHOR]

Abstract: The search for hybrid organic-inorganic materials remains a great challenge in the field of ferroelectrics. Following the discovery of the room temperature ferroelectric material (MV)[BiI3Cl2] (MV2+: methylviologen) exhibiting the highest polarization value in the field of hybrid ferroelectrics, we report here nine new hybrids with the general formulation (MV)[M(III)X5−x X′ x ] (M=Bi, Sb; X, X′=Cl, Br, I): (MV)[BiCl3.3Br1.7] (1), (MV)[BiCl1.3Br3.7] (2), (MV)[BiBr3.2I1.8] (3), (MV)[SbCl5] (4), (MV)[SbBr5] (5), (MV)[SbCl3.8Br1.2] (6), (MV)[SbCl2.4Br2.6] (7), (MV)[SbI3Cl2] (8) and (MV)[SbBr3.8I1.2] (9). Depending on the presence of polar chains or not, and on the coupling of polar chains, two types of centrosymmetrical structures [C1] and [C2] and two types of polar structures [P1] and [P2] are defined. (2) undergoes a paraelectric-to-relaxor ferroelectric transition around 100–150K depending of the frequency showing that the Curie temperature, T C , of (MV)[BiBr5] (243K) can be modulated by the substitution of Br by Cl. The most interesting family is the [P2] type because the syn coupling of polar chains is in favor of high polarization values, as in (MV)[BiI3Cl2]. Five of the nine new hybrids, (4), (6–9), which have the [P2] type structure are potential ferroelectrics. [Copyright &y& Elsevier]

On the basis of the reported radical neutral complex [Au(Et-thiazdt)2] (Et-thiazdt = N-ethyl-1,3-thiazoline -2-thione-4,5-dithiolate), a series of single-component conductors derived from [Au(Et-thiazdt)2], also noted as [AuS4(-S)2], has been developed, by replacing the outer sulfur atoms of the thiazoline-2-thione rings by oxygen atoms and/or by replacing the coordinating sulfur atoms by selenium atoms toward the corresponding diselenolene complexes. Comparison of the X-ray crystal structures and transport properties of the four isostructural complexes, noted as [AuS4(-S)2], [AuS4(-O)2], [AuSe4(-S)2], and [AuSe4(-O)2], shows that the oxygen substitution on the outer thiazoline ring actually decreases the conductivity by a factor of 100, despite a contracted unit cell volume reflecting a positive chemical pressure effect. On the other hand, the S/Se substitution increases the conductivity by a factor of 100, and the pressure needed to transform these semiconductors into the metallic state is shifted from 13 kbar in [AuS4(-S)2] to only ≈6 kbar in [AuSe4(-S)2]. Analysis of unit cell evolutions and ab initio band structure calculations demonstrates the strongly anisotropic nature of this chemical pressure effect and provides an explanation for the observed changes in conductivity. The greater sensitivity of these neutral single-component conductors to external pressure, as compared with "classical" radical salts, is also highlighted. [ABSTRACT FROM AUTHOR]

Combining recent concepts from the fields of molecular conductivity and molecular machinery we set out to design a crystalline molecular conductor that also possesses a molecular rotor. We report on the structures, electronic and physical properties, and dynamics of two solids with a common 1,4-bis(carboxyethynyl)bicyclo[2.2.2]octane (BABCO) functional rotor. One, [nBu4N+]2[BABCO][BABCO-]2, is a colorless insulator where the dicarboxylic acid cocrystallizes with two of its monoanionic conjugated bases. The other is self-assembled by electrocrystallization in the form of black, shiny needles, with highly conducting molecular slabs of (EDT-TTF-CONH2)2+ (EDT-TTF = ethylenedithiotetrathiafulvalene) and anionic [BABCO-] rotors. Using variable-temperature (5-300 K) proton spin-lattice relaxation, 1H T1-1, we were able to assign two types of Brownian rotators in [nBu4N+]2[BABCO][BABCO-]2. We showed that neutral BABCO groups have a rotational frequency of 120 GHz at 300 K with a rotational barrier of 2.03 kcal mol-1. Rotors on the BABCO- sites experience stochastic 32 GHz jumps at the same temperature over a rotational barrier of 2.72 kcal mol-1. In contrast, the BABCO- rotors within the highly conducting crystals of (EDT-TTF-CONH2)2+[BABCO-] are essentially "braked" at room temperature. Notably, these crystals possess a conductivity of 5 S cm-1 at 1 bar, which increases rapidly with pressure up to 50 S cm-1 at 11.5 kbar. Two regimes with different activation energies Ea for the resistivity (180 K above 50 and 400 K below) are observed at ambient pressure; a metallic state is stabilized at ca. 8 kbar, and an insulating ground state remains below 50 K at all pressures. We discuss two likely channels by which the motion of the rotors might become slowed down in the highly conducting solid. One is defined as a low-velocity viscous regime inherent to a noncovalent, physical coupling induced by the cooperativity between five Csp3-H⋯O hydrogen bonds engaging any rotor and five BABCO units in its environment. The rotational barrier calculated with the effect of this set of hydrogen bonds amounts to 7.3 kcal mol-1. Another is quantum dissipation, a phenomenon addressing the difference of dynamics of the rotors in the two solids with different electrical properties, by which the large number of degrees of freedom of the low dimensional electron gas may serve as a bath for the dissipation of the energy of the rotor motion, the two systems being coupled by the Coulomb interaction between the charges of the rotors (local moments and induced dipoles) and the charges of the carriers. [ABSTRACT FROM AUTHOR]

The search for hybrid organic-inorganic materials, which have the great advantage that they can be synthesized at moderate temperature (T < 200 °C), remains a great challenge in the field of ferroelectrics. Here, a room-temperature ferroelectric material with interesting characteristics, (MV)[BiI3Cl2] (MV2+ = methylviologen), is reported. Its structure is based on polar inorganic chains resulting from a remarkable Cl/I segregation induced by methylviologen entities, which coincide with the fourfold polar axis of the tetragonal structure. Of great importance is that this room-temperature hybrid ferroelectric displays a clear electrical hysteresis loop with a large spontaneous polarization (>15 μC∙cm-2). [ABSTRACT FROM AUTHOR]

An efficient synthetic procedure for the preparation of unsymmetrically substituted tetrathiafulvalene (TTF) donors has been used to obtain the trimethylene-tetrathiafulvalene (tTTF) donor with high purity. Good quality crystals of the two (tTTF)2X (X = Br, I) salts have been obtained by electrocrystallization. The two salts are isomorphous and contain tTTF layers which are built from (tTTF)2 dimeric units. Both systems are low-dimensional antiferromagnets with the highest Neel temperatures for TTF based radical cation salts: ≈ 35 K (Br salt) and ≈43 K (I salt). The resistivity is found to substantially decrease with pressure although both salts still have activated conductivity at 25 kbar. First-principles Density Functional Theory (DFT) calculations have been used to investigate the relative strength of the three different types of magnetic interactions in the tTTF layers as well as the potential magnetic ground states. These calculations successfully predict the nature of the ground state and suggest a possible correlation between structural details and Neel temperatures for the bromine and iodine salts. Remarkably, the calculated antiferromagnetic ground state can be predicted from the nesting properties of the Fermi surface for the hypothetical Pauli paramagnetic metallic state. [ABSTRACT FROM AUTHOR]

Syntheses, X-ray structural analyses, thermal behaviors, photochromism, and electrical properties of a series of methylviologen (MV2+) halobismuthate hybrids, namely, (MV)3[Bi4CI18](H2O)y (la, y 1.7), (MV)4[Bi6CI2e](H2O)x (2a, y 1.7), (MV)4[Bi6CI24.6I1.4](H2O)x(3a, y 1.5), and (MV)4[BieCl24.6I1 4](H2O)x (4a, y 1.3), are reported. Because of the thermal effect of a UV lamp or as a result of being heated up to 100 °C, all of the above compounds undergo a complete (la, 2a, and 3a) or a partial (4a) dehydration together, in 2a and 3a, with an impressive structural reorganization involving a 900 rotation of methylviologen dimers and, in 3a, a new Cl/I distribution, finally leading to (MV)3[Bi4CI18I (ib), (MV)4[Bi6CI26] (2b), (MV)4[BieCI2eeIo4] (3b), and (MV)4[Bi6Cl24.6l14](H2O). (4a, x 0.65), respectively. In its turn, 4a (x 0.65) undergoes an abrupt structural change at 160°C when water molecules are completely removed, leading to (MV)4[Bi6CI24.6 I1.4] (4b). Obviously, the two first dehydrated phases can be considered as the n = 2 (1 b) and n = 3 (2b) members of the (MV)(2n+2v2[Bi2nCI2} family, and the ultimate member (n = ∞) with an infinite 10 double-chain inorganic framework, namely, (MV)[Bi2CI8], has already been reported. According to the results of structural refinements, some positions of the CI atoms in the [Bi6C126]8- anionic cluster of 3a and 4a have been occupied by t atoms, finally leading to iodidedoped materials of the 2a type (percentage of doping: 3a, 1.5%; 4a, 5.4%). Upon UV irradiation, yellow crystals of 2a and 3a (which become 2b and 3b because of the thermal effect of the UV lamp) or yellow crystals of 2b, 3b, and 4a undergo a color change to black crystals (in the case of 2b), as observed in (MV)[Bi2CI8], or light-brown crystals (in the cases of 3b and 4a). These photochromic properties are probably due to the photoinduced electron transfer from the anionic part to the methylviologen dications. In contrast, no color change is observed when yellow crystals of la or lb and the iodide-doped (MV)[Bi2CI8ϵIϵ] material are irradiated. Because the relative positions of meth~ylviologen to the host anionic frameworks are comparable in all structures (the N-CI distances are about 3.4 A), these results indicate that such kinds of photochemical reactions depend on the dimension of the anionic networks, as well as the iodide doping. The single-crystal electrical conductivity measurements of 2b before and after irradiation were carried out between 150 and 393 K. The results prove that both of them are semiconductors with weak room temperature conductivity and that the band gap of the irradiated crystal (2b, 0.35 eV) is much smaller than that of the original hybrid 2a (1.0 eV). [ABSTRACT FROM AUTHOR]

A single component molecular conductor has been isolated from electrocrystallization of the monoanionic gold bis(dithiolene) complex based on the N-ethyl-1,3-thiazoline-2-thione-4,5-dithjolate (Et-thiazdt) ligand. The crystal structure of the system exhibits layers built from parallel uniform one-dimensional stacks of the planar molecule. At room temperature and ambient pressure the system is semiconducting (0.33 Scm1) with a small activation energy. However, the single crystal conductivity is strongly pressure dependent reaching 1000 S·cm-1 at 21 kbar. At 13 kbar there is a crossover between semiconducting and metallic regimes. Thus, the present system is the first well characterized single-component molecular metal without TTF dithiolate ligands. First-principles DFT calculations show that the ground state is antiferromagnetic with a very small band gap. A simulation of the effect of pressure on the electronic structure provides a rationale for the observed variations of the conductivity and gives insight on how to further stabilize the metallic state of the system. [ABSTRACT FROM AUTHOR]

A series of 2D metals, β-(BDT-UP)6[Re6Se6Cl8]·(CHCl2-CHCl2)2, 2; β-(ST-UP)6[Re6S6Cl8]·(CH2-Cl-CHCl2)2, 3; β-(BDT-UP)7[Re6S6Cl8]0.5[Re6S7Cl7]0.5·(CH2Cl2), 4; β-(BDT-UP)7[Re6Se6Cl8]0.5[Re6S7- Cl7]0.5(CH2Cl2), 5; β-(BDT-UP)8[Re6S7Cl7]·(CH2Cl2)4, 6 (BDT-TTP and ST-UP are 2,5-bis(1,3-dithiol-2- ylidene)-1,3,4,6-tetrathiapentalene and 2-(1,3-diselenol-2-ylidene)-5(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, respectively) is reported to have one single β-slab layered topology despite successive increases of the cluster anion negative charge. The charge density within the templating composite inorganic-neutral molecule slab is shown to remain above a threshold of ca. one negative charge per square nanometer, that is, for cluster anions with two negative charges and higher. Conversely, discrete stacks are shown to be stabilized instead in the semiconducting salts (BDT-TTP)2[Re6S5Cl9], 1 where the cluster anion bears one negative charge only. The electronic structure of salts 2-6 is shown to be very stable and kept almost intact across the series. The templating strategy is shown to fulfill its anticipated potential for deliberate installment of incommensurate band fillings in molecular metals. The deliberate admixture of the 6:1 and 8:1 structures yields novel phases with a 7:1 stoichiometry with the anticipated crystal and electronic structures. The action at the organic-inorganic interface triggered by changing the anion charge yet keeping its shape and volume identical, which ultimately governs the shape of the unit cell, is of paramount importance in defining the Fermi surface of these metallic salts. The present BDT-UP salts thus provide a series of materials with strongly related but subtly different Fermi surfaces worthy of many physical studies. Shubnikov-de Haas measurements are expected to be particularly interesting since they are especially sensitive to the details of the Fermi surface. [ABSTRACT FROM AUTHOR]

(EDT-TTF-CONH2)6[Re6Se8(CN)6], space group R..., was prepared by electrocrystallization from the primary amide-functionalized ethylenedithiotetrathiafulvalene, EDT-TTF-CONH2 (E½1 = 0.49 V vs SCE in CH3CN), and the molecular cluster tetraanion, [Re6Se8(CN)6]4- (E½ = 0.33 V vs SCE in CH3CN), equipped with hydrogen bond donor and hydrogen bond acceptor functionalities, respectively. Its Kagome topology is unprecedented for any TTF-based materials. The metallic state observed at room temperature has a strong two-dimensional character, in coherence with the Kagome lattice symmetry, and the presence of minute amounts of [Re6Se8(CN)6](3-)· identified by electron spin spectroscopy. A structural instability toward a distorted form of the Kagome topology of lesser symmetry is observed at ca. 180 K. The low-temperature structure is associated with a localized, electrically insulating electronic ground state and its magnetic susceptibility accounted for by a model of uniform chains of localized S = ½ spins in agreement with the 100 K triclinic crystal structure and band structure calculations. A sliding motion, within one out of the three (EDT-TTF-CONH2)2 dimers coupled to the [Re6Se8(CN6)(3-)·]/[Re6Se8(CN6)4-] proportion at any temperature, and the electronic ground state of the organic-inorganic hybrid material are analyzed on the basis of ESR, dc conductivity, ¹H spin-lattice relaxation, and static susceptibility data which qualify a Mon localization in [EDT-TTF-CONH2]6[Re6Se8(CN)6]. The coupling between the metal-insulator transition and a structural transition allows for the lifting of a degeneracy due to the ternary axis in the high temperature, strongly correlated metallic phase which, in turn, leads to Heisenberg chains at low temperature. [ABSTRACT FROM AUTHOR]

Studies the deliberate design of a series of single crystals of conducting two-dimensional radical cation salts of o-bis(amide)-appended ethylenedithiotetrathiafulvalene and of their parent monocomponent solid ethylenedithiotetrathiafulvalene. Presence of a robust and adaptable hydrogen bond network in single-component solids; Preservation of the slab topology in radical cation salts; Restoration of an organic-inorganic interface.

The ability of I···I van der Waals interactions to direct the self-assembly of slabs of the radical cation of ethylenedithio-1,2-diiodo-tetrathiafulvalene, EDT-TTF-I[sub 2], and polymeric lead iodide covalent anionic layers is demonstrated by the synthesis of single crystals of β-(EDT-TFF-I[sub 2])[sub 2, sup •+][(Pb[sub 5/6...1/6]I[sub 2])[sup 1/3-]][sub 3], triclinic, P-1, a = 7.7818(8), b = 7.9760(8), c = 19.9668(2) Å, α = 82.409(12), β = 85.964(12), γ = 61.621(11)°, V = 1080.76(19) ų, R1, wR2 = 0.0459, 0.0947; and β-(EDT-TTF-I[sub 2])[sub 2, sup •+][(Pb[sub 2/3+x]Ag[sub 1/3-2x...x] I[sub 2])[sup 1/3]][sub 3], x ≈ 0.05, triclinic, P-1, a = 7.7744(8), b = 7.9193(8), c = 19.834(2) Å, α = 87.189(12), β = 83.534(12), γ = 61.602(11)°, V = 1067.4(2) ų, R1, wR2 = 0.0508, 0.0997. The state-of-the-art, combined microprobe and structural analysis of the metal site vacancies and occupancies patterns reveal a commensurate organic-inorganic interface and point out the importance of halogen···halogen van der Waals interactions to future studies aiming at directing interface topologies. The electronic structure, room-temperature metallic character and metal-insulator transition at ca. 70 K of the two-dimensional organic slabs are retained upon alloying of the inorganic sublattice with monocations. The room-temperature conductivity of the metallic lead-silver alloy is 2 orders of magnitude larger than that of β-(EDT-TTF-I[sub 2])[sub 2, sup •+][(Pb[sub 5/6...1/6]I[sub 2])[sup 1/3-]][sub 3]. This calls for the study of materials with diverse alloying patterns with metal cations of different nature and charge. [ABSTRACT FROM AUTHOR]

[EDO-TTF-CONH2][TCNQF4], triclinic system, space group P-1, a=8.2479(12) A˚, b=12.282(2) A˚, c=12.6842(18) A˚, α=113.850(17)°, β=106.420(17)°, γ=90.284(19)°, V=1116.8(4) A˚3; and [EDT-TTF-CONH2]2[TCNQF4], triclinic system, space group P-1, a=6.5858(9) A˚, b=11.699(2) A˚, c=12.2281(18) A˚, α=104.000(19)°, β=93.611(17)°, γ=98.279(19)°, V=899.9(3) A˚3, whose π-donor molecules, (ethylenedioxo)-carbamoyltetrathiafulvalene and (ethylenedithio)-carbamoyltetrathiafulvalene, respectively, differ solely by the nature of the chalcogen atoms in their outer ethylene dichalcogeno bridge, yet form very different charge-transfer complexes with the same π-acceptor. [EDO-TTF-CONH2•+]2 [TCNQF4•−]2 is a diamagnetic insulating ionic salt with a three-dimensional rock-salt-type structure based on discrete dimers while in the semi-conducting mixed-valence complex, [EDT-TTF-CONH2]2•+[TCNQF4•−], the mixed-valence dimers aggregate into infinite chains interspersed within parallel rows of non-interacting radical anions. It is shown how the robust and adaptable supramolecular amide hydrogen bond tweezers-like motifs common to the two solids simply comply to the 3-to-1 dimensionality reduction upon substitution of O for S. [Copyright &y& Elsevier]

Using a slow liquid–gas diffusion method, the mixed-valence viologen salt (MV)2(BF4)3 (1) and the radical cation salt (MV)(BF4) (2) are crystallized. Both structures contain regular stacks of MVṖ+ radical cations (2) or alternating MVṖ+ and MV2+ entities (1). A short intrastack intermolecular separation (3.23 Å) unprecedently reveals strong interactions between MV2+ and MVṖ+ in 1. [ABSTRACT FROM AUTHOR]

The synthesis of the superconductor κ-(BEDT-TTF) 2 Cu(NCS) 2 is optimized following a two-pot procedure to obtain high quality nanoparticles This leads to homogeneous sized-nanoparticles, 30 nm diameter, which are further characterized by XRD and Raman spectroscopy. SQUID measurements confirm the occurrence of the superconducting transition at 9.1 K. [ABSTRACT FROM AUTHOR]

The article discusses the syntheses, structure and properties of chiral molecular metals. Within the extended series of organic metals and superconductors based on tetrathiafulvalene (TTF) and derivatives, the introduction of chirality offers an invaluable opportunity to evaluate the role of disorder on the conductive properties since radical cation salts of enantiopure donors are expected to suffer less from structural disorder than those of racemates, where the crystal structure may tolerate the enantiomers exchanging places.