A series of stable salts of the oxidized donors TTF, o-Me2TTF,TMTTF, and TTF(SCH2CH2CN)4

Reactions of the organic donors tetrathiafulvalene (TTF), o-dimethyltetrathiafulvalene (o-Me₂TTF), tetramethyltetrathiafulvalene (TMTTF), and tetrathiafulvalene tetrathiolate [TTF(SCH₂CH₂CN)₄] with oxidizing agents of suitable potential resulted in the formation of stable salts in which the donors are present in their monocationic radical forms. The salts presented herein represent a series of reagents containing oxidized chalcofulvalene donors that can be used as starting materials for metathesis reactions with other cations. All of the salts were characterized by X-ray crystallography and UV–vis–NIR spectroscopy.     

In the search of an electron transfer between π-donors and C60: the bis-linking of tetrathiafulvalene (TTF) to C60

In order to realize the bis-linking of tetrathiafulvalene (TTF) to one or two C₆₀, and to reach the dyad compounds 1 and 2, the [4 + 2] Diels-Alder reactions of C₆₀ with orthoquinodimethanic derivatives of 1,3-dithioles 5a,b or TTF 9 are studied.     

Conductive complexes of [Ni(dmid)2] with TTF,TMTTF, and ET

Three charge-transfer salts of [Ni(dmid)₂]⁻ (dmid: 1,3-dithiol-2-one-4,5-dithiolate)—TMTTF[Ni(dmid)₂], TTF_x[Ni(dmid)₂] and ET_x[Ni(dmid)₂] (TMTTF: tetramethyl-tetrathifulvalene, TTF: tetrathifulvalene, ET: bis(ethylenedithio)-tetrathiafulvalene) are prepared and characterized. The TMTTF[Ni(dmid)₂] complex has a structure with mixed packs is formed by cations and anions, which alternate each other with subsequent shift. This compound is semiconductor with the room-temperature conductivity of 2.2 × 10⁻³ Ω⁻¹ cm⁻¹. The TTF_x[Ni(dmid)₂] and ET_x[Ni(dmid)₂] complexes have a highest conductivity: σ_RT 1.86 and 0.54 Ω⁻¹ cm⁻¹, respectively.     

4 K crystallographic and electronic structures of (TMTTF)2X salts (X−: PF6−, AsF6−

The 4 K crystallographic and electronic structures of (TMTTF)₂PF₆ and (TMTTF)₂AsF₆ are presented. The structural investigation was performed by neutron diffraction. Thermal expansion and structural data are compared to those of the Se analogues. The tight-binding band electronic structures are based on calculations of the transfer integrals within the dimer splitting approximation. The results are discussed and compared to the room-temperature values. The trasfer integrals of the two salts, which are very similar at 300 K, tend to differ markedly at low temperature. The observed differences in the transfer integrals are related to the changes of the orientation of two neighbouring organic chains. The variations of the electronic parameters appear to depend on the anion.     

Synthesis of tetra-silylated tetrathiafulvalene derivatives TTF(SiR2H)4 (R = Me,Ph): Novel assembling ligands for the construction of bimetallic transition metal complexes

The HR₂Si-functionalized tetrathiafulvalene (TTF) ligand TTF(SiR₂H)₄ (R = Me 2a; R = Ph 2b) have been synthesized and the molecular structure of 2a determined. The reactivity of the four Si–H bonds for oxidative addition reactions has been exploited. Thus, the bimetallic platinum–silicon complex [(PPh₃)₂Pt{(Me₂Si)₂TTF(SiMe₂)₂}Pt(PPh₃)₂] 3 incorporating TTF(SiMe₂H)₄ as bridging unit has been assembled by oxidative addition across [Pt(PPh₃)₂(CH₂CH₂)]. Electrochemical investigations by means of cyclic voltammetry reveals, for the complex 3, a strong cathodic shift of the two redox processes of the TTF core compared with those of 2a.     

Pressure-induced structural phase transition in the Bechgaard-Fabre salts

The crystal structures of the quasi-one-dimensional organic salts (TMTTF)₂PF₆ and (TMTSF)₂PF₆ were studied by pressure-dependent X-ray diffraction up to 10 GPa at room temperature. The unit-cell parameters exhibit a clear anomaly due to a structural phase transition at 8.5 and 5.5 GPa for (TMTTF)₂PF₆ and (TMTSF)₂PF₆, respectively.     

Synthesis of CETBz-TTF and CESBz-TTF: Preparation, structural and physical properties of their radical salts with paramagnetic Cu(II) complex anions

CETBz-TTF (4,5-bis(cyanoethylthio)benzo-tetrathiafulvalene) and CESBz-TTF (4,5-bis(cyanoethylseleno)benzo-tetrathiafulvalene) 5 have been synthesized from cyano precursor via a cross-coupling reaction. Radical salts with paramagnetic Cu(II) complex anions, such as (CETBz-TTF)₂CuCl₄ 6 and (CESBz-TTF)₂CuCl₄ 7 have been prepared. X-ray crystal structure and physical properties of these new compounds are presented.     

Synthesis,characterization and electrical and CO2 sensing properties of triazine containing three dendritic phthalocyanine

The metal-free phthalocyanine 1a was synthesised by statistically mixed condensation of 4-nitrophthalonitrile and 4-(2-dimethylaminoethylsulfanyl)phthalonitrile in dry 2-(dimethylamino)ethanol. The same route were applied to prepare metal-containing phthalocyanines using metal salts Zn(OAc)₃·2H₂O and CoCl₂, respectively, in dry DMF. The nitro compounds were reduced to amine with sodium sulfide and quarternized by reaction of MeI. These compounds were then reacted with cyanuric chloride in the presence of potassium carbonate as a base in mixture of THF and DMF gave s-triazine containing three amino phthalocyanines 4a–c. The reaction of three phthalocyanines with sodium salt of triethylmethanetricarboxylate in absolute ethanol were synthesised first generation of dendrimer 5a–c. The second generation of dendritic phthalocyanines 6a–c were prepared by the reaction of dentritic phthalocyanines with tris (H₂NC(CH₂OH)₃) using K₂CO₃ as a base in DMSO. The dendritic phthalocyanines containing tris are slightly soluble in water. The new compounds were characterized by elemental analysis and UV–vis, IR, NMR spectra. The temperature dependence of the dc and ac conductivity of these compounds and the adsorption of CO₂ gas on thin film of the compounds were investigated by dc conductivity and impedance spectroscopy technique using an interdigital transducer structure on glass substrate. While exposure to CO₂ have no influence on the electrical conductivity (ac and dc) of compound 6a and 6c, the conductivity of the film of 6b strongly depend on the presence of the CO₂ gas. Completely reversible sensor signals were obtained for compound 6b. The impedance spectra were obtained at frequencies between 40 and 10⁵ Hz, and in a wide range of CO₂ concentrations (from 500 to 8000 ppm) at room temperature. The temperature dependence of dc conductivity show typical Arrehenius behaviour for all compounds. The ac conductivity of the films is represented by the form ω^s. The dependency of frequency exponent s on temperature suggests a correlated barrier hopping (CBH).     

New TTF and bis-TTF containing thiophene units: Electrical properties of the resulting salts

Series of new TTF and bis-TTF containing a thiophene ring as a substituent or as a spacer group were prepared by using a palladium-catalyzed cross-coupling reaction from tributylstannyl–trimethyltetrathiafulvalene (tMeTTF–SnBu₃) and different halogeno and dihalogenothiophene derivatives. The reducing power of each new precursor was determined by cyclic voltammetry. Radical cations salts and charge transfer complexes of the donors with TCNQ were prepared and characterized. The electrical conductivity of these materials was measured and discussed in terms of (electronic) structure.     

Tetraazafulvalenediide salts of tetrathiafulvalene

Synthesis and characterization of the tetrathiafulvalenium salts, (TTF)₃X, where X are the dianions of tetracyano and tetrabromotetraaza-fulvalene, are reported. These fulvalene-fulvalene salts with formal TTF^0.67+ are found to be semiconductors with room-temperature powder compaction resistivities in the range of 10²–10³ Ω cm.     

Synthesis and electrochemical properties of novel oligo-TTF donors

A series of novel oligomeric electron donors containing two to six TTF cores (5–11) were synthesized. The structures were assigned by NMR spectroscopy, infrared spectrometry and mass spectra. Their electrochemical properties were investigated by cyclic voltammetry (CV). All the compounds exhibited two pairs of nearly ideal redox waves. No distinct shift of the redox potentials was observed when TTF units increased.     

Synthesis of brominated tetrathiafulvalenes via phosphite-mediated cross-coupling

The synthesis of polybrominated tetrathiafulvalenes (TTF–Br_n, 2–4) containing 2–4 bromine atoms via phosphite-mediated cross-coupling of bromo-substituted 1,3-dithiole-2-thiones and 1,3-dithiole-2-ones is reported.     

Effect of substituent groups for formation of organic-metal hybrid nanowires by charge-transfer of tetrathiafulvalene derivatives with metal ion

Effect of substituent groups on a tetrathiafulvalene (TTF) unit for formation of organic-metal hybrid nanowires was studied. Depend on the substituent groups, the nanowires were obtained as a precipitate just by mixing TTF derivatives and HAuCl₄ in CH₃CN solution at room temperature via electron transfer reaction between the TTF derivatives and a gold ion. To precede favorably hybrid nanowire formation, increase planarity and introduction of strong interaction on the TTF derivatives are required.     

Crystalline patterns and band structure dimensionality in a series of conducting hybrids associating amide-functionalized EDT-TTF π-donors with the isosteric octahedral anions [FeNO(CN)5]2− and [M(CN)6]3− (M = Co,Fe)

Four new radical cation salts based on the amide functionalized EDT-TTF organic donors EDT-TTF-CONH₂ (D1) and EDT-TTF-(CONH₂)₂ (D2), α′-(D1)₄[FeNO(CN)₅] (1), α′-(D1)₄[Co(CN)₆] (2), β-(D1)₆[Fe(CN)₆] (3) and (D2)₄[FeNO(CN)₅]NB (4), have been synthesized and characterized by X-ray single crystal diffraction experiments, band structure calculations and electrical resistivity measurements. Functionalized organic donors are remarkable for the ability to form cation⋯cation and cation⋯anion type hydrogen bonds which can effectively direct the crystal architecture of molecular conductors. The structural analysis reveals a well-developed hydrogen bond network in the crystals investigated. (D1)₂-dimers or (D2)_n-extended zigzag chains of donors connected through functional groups are found to be stable structural motifs in 1–4. Remarkably, salts 1 and 2 are isostructural despite the presence of anions of different charge (−2 and −3, respectively) and the inherent difference in the degree of charge transfer has a clear effect on the transport properties: σ_RT(2)/σ_RT(1) = 300. Salt 3 differs from 1 and 2 both in the stoichiometry and packing of the conducting organic layer. Crystals of 4 exhibit a superstructure with the incommensurate vector q = ±(0.5, 0.3, 0.2).     

Polymerization of fluorene-based monomers modified with thiavinylidene structure at 9-position and their optical properties

Two iodo-functionalized fluorene-based monomers having a thiavinylidene moiety at 9-position [2,7-diiodo-9-(n-hexylthiavinylidene)fluorene and 2,7-diiodo-9-((2-(2-methoxyethoxy)ethyl)thiavinylidene)fluorene] were synthesized. Suzuki coupling reactions with thienylboronic acids bearing a n-hexyl chain were subsequently conducted to obtain two thiophene-functionalized monomers [2,7-bis(4-hexylthienyl)-9-(n-hexylthiavinylidene)fluorene and 2,7-bis(3-hexylthienyl)-9-(n-hexylthiavinylidene)fluorene]. The dehalogenative polycondensation using Ni(cod)₂/cod/bpy system and the oxidation coupling polymerization using FeCl₃ gave three homopolymers (HP1, HP2, and HP3). The polymerization under Suzuki coupling condition gave three copolymers (CP1, CP2, and CP3). The number-averaged molecular weights ranged from 2500 to 23,000. The optical properties of polymer were dependent upon the character of arylene unit. Namely, HP1 solely consisting of a 9-(n-hexylthiavinylidene)fluorene segment demonstrated the short absorption maximum wavelength but the large red-shift (13 nm) from the solution state to film state. CP3 having a hydrophilic side chain showed the larger red-shift (13 nm) as compared with CP2 bearing the similar backbone and a hydrophobic side chain.     

Multi-component molecular conductors with supramolecular assembly based on ET radical cation salts with (NO3)− anion

Synthesis, structure and conducting properties of two new multi-component radical cation ET salts with the (NO₃)⁻ counterion: (ET)₂(NO₃)·C₂H₄(OH)₂ (I) and (ET)₂(NO₃)·0.5[C₂H₄(OH)₂]·H₂O (II) are described. Both salts have layered structures with the distinguishing feature of hydrogen bonds being present between the radical cation layers and anion sheets. It was found that introduction of glycol molecules to compositions of I and II significantly affects the structure of their cation and anion layers and, as a result, their conducting properties. I is a semiconductor, while II demonstrates metallic conductivity down to 4.2 K.     

The first BDH-TTP radical cation salts with mercuric counterions, κ-(BDH-TTP)4[Hg(SCN)4]·C6H5NO2 and α′-(BDH-TTP)6[Hg(SCN)3][Hg(SCN)4]

Two new radical cation salts of the non-TTF containing donor BDH-TTP with the thiocyanatomercurate anions were synthesized. The κ-(BDH-TTP)₄[Hg(SCN)₄]·C₆H₅NO₂ (1) and α′-(BDH-TTP)₆[Hg(SCN)₃][Hg(SCN)₄] (2) salts were characterized by single crystal X-ray diffraction, electrical resistance measurements and electronic band structure calculations. Both salts have a layered structure in which the BDH-TTP layers of κ- or α′-type alternate with anionic sheets. The anionic layers of 1 contain the counterion [Hg(SCN)₄]²⁻ and the nitrobenzene molecule which are statistically disordered. Salt 2 contains two different layers (although both of the α′-type) of the organic donors, a somewhat unusual fact in organic conductors. The anion layers of 2 consist of polymeric chains built up from a combination of the two different anions, [Hg(SCN)₃]¹⁻ and [Hg(SCN)₄]²⁻. Salt 1 shows a metallic behavior down to helium temperatures whereas salt 2 exhibits two-phase transitions in the temperature range 295–8 K.     

Tris-fused tetrathiafulvalenes (TTF): highly conducting single-component organics and metallic charge-transfer salt

Tris-fused tetrathiafulvalene (TTF) derivatives, TTC_n-TTPY, 2,2′-bis[4,5-alkylthio-(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalenylidene] with four alkylthio chains [C_nH_2n+1S: n=3–5] are prepared and the structural and conducting properties are investigated. Crystals of the neutral molecules show very low electrical resistivity (400 Ω cm) as single-component pure organic materials. Irrespective of the alkylthio chain length, the crystal structures are so-called β″-type consisting of uniform stacks of the tris-fused TTF parts. Iodine-doped TTC₃-TTPY exhibits metallic conductivity down to liquid helium temperature.     

Synthesis,crystal structures and properties of new radical cation salts based on some tetrathiapentalene derivatives with halogenomercurate anions

New radical cation salts of BDH-TTP [2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene], BDA-TTP [2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] and DTDH-TTP [2-(1,3-dithiol-2-ylidene)-5-(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene] with halogenomercurate anions have been prepared. X-ray analysis at 120 K revealed the κ-type arrangement of conducting donor layers in (BDH-TTP)₄Hg₃Br₈ and (BDH-TTP)₄Hg₃Cl₈, and the β-type packing of donor layers in the (BDA-TTP)₄Hg₂Br₆, (BDA-TTP)₆Hg₄I_10.34 and (DTDH-TTP)₆Hg₃Br₉ radical cation salts. The crystals of κ-(BDH-TTP)₄Hg₃Br₈, κ-(BDH-TTP)₄Hg₃Cl₈ and β-(DTDH-TTP)₆Hg₃Br₉ behave as metals down to liquid helium temperatures, the resistivity of BDA-TTP salts shows semiconducting temperature dependence.     

Synthesis and properties of μ-cyano(phthalocyaninato)-rhodium(III)

This contribution reports on the synthesis of μ-cyano(phthalocyaninato)rhodium(III), [PcRhCN]_n (1), by splitting off potassium cyanide from potassium(dicyano)phthalocyaninatorhodium(III), K[PcRh(CN)₂] (2). Monomeric complexes, PcRh(L)CN (7), were formed when [PcRhCN]_n (1) was treated with base molecules L, such as n-butylamine and pyridine. All compounds were characterized by IR, far-IR spectroscopy, thermal and elemental analyses, and partly by UV, ¹H-NMR and FD (field desorption) mass spectroscopy. The undoped polymer [PcRhCN]_n (1) exhibits a d.c. dark conductivity of 4 × 10^?4 S/cm, which was diminished by eight orders of magnitude when the polymeric structure was decomposed by treatment with a competing ligand.