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In the search for high performance n-type organic semiconductors (OSCs) a simple strategy might be substitution of aromatic CH groups for nitrogen heteroatoms. Here, we report the synthesis and characterisation of two novel N-heteroacene compounds, namely, 1,5,12-triazatetracene (TrAT1) and 2,5,12-triazatetracene (TrAT2). Their potential as n-type materials is evaluated against 5,12-diazatetracene (DAT) by UV/vis and EPR spectroscopy, cyclic voltammetry, DFT, single crystal X-ray diffraction and thin film characterisation. Increasing the number of N-heteroatoms was found to stabilise the HOMO and LUMO leading to electron affinities for TrAT1 and TrAT2 of ca. −4 eV. Both compounds were found to exhibit columns of co-facial π-stacked molecules. For TrAT1, molecules are also linked by hydrogen bonding, while the crystal structure of TrAT2 was found to be inherently disordered. Thin films of DAT, TrAT1 and TrAT2 were grown by organic molecular beam deposition (OMBD) and found to form discontinuous films, where TrAT1 exhibited a preferential orientation.

We report the first example of a chiral BDH-TTP radical-cation salt. Chirality is induced in the structure via the use of a chiral spiroboronate anion where three stereocentres are present, one on each chiral ligand and one on the boron centre. Despite starting from a labile racemic mixture of BS and BR enantiomers, only one enantiomer is present in the crystal lattice. The anions pack in a novel double anion layer which is the thickest anion layer found in a BDH-TTP salt. This material is chiral and shows metallic behaviour down to at least 4.2 K.

The synthesis of a novel amide-functionalised 2,6-bis(pyrazol-1-yl)pyridine-4-carboxamide ligand (bppCONH2) is described. The complex salts [Fe(bppCONH2)2](BF4)2 and [Fe(bppCONH2)2](ClO4)2 were synthesised and characterised by SQUID magnetometry, differential scanning calorimetry, variable temperature Raman spectroscopy and single crystal X-ray diffraction. DSC measurements of [Fe(bppCONH2)2](BF4)2 indicate a spin-crossover (SCO) transition with T↑ at 481 K and T↓ at 461 K, showing a 20 K hysteresis. DSC for the perchlorate salt shows an SCO transition with T↑ at 459 K and T↓ at 445 K with a 14 K hysteresis. For the BF4− salt analysis of low and high-spin state crystal structures at 101, 290 and 500 K, suggest stabilisation of the low spin state due to the formation of 1D hydrogen-bonded cationic chains. Variable temperature Raman studies of the BF4 salt support the presence of a high temperature SCO. It is speculated that the presence of hysteresis may be attributed to differences in the inter-molecular hydrogen bonding in the low spin and high spin states.

Peter Day’s research group reported the first molecular superconductor containing paramagnetic metal ions in 1995, β″-(BEDT-TTF)4(H3O)Fe(C2O4)3·C6H5CN. Subsequent research has produced a multitude of BEDT-TTF-tris(oxalato)metallate salts with a variety of structures and properties, including 32 superconductors to date. We present here the synthesis, crystal structure, and conducting properties of the newest additions to the Day series including the first superconductor incorporating the diamagnetic tris(oxalato)aluminate anion, β″-(BEDT-TTF)4(H3O)Al(C2O4)3·C6H5Br, which has a superconducting Tc of ~2.5 K. β″-(BEDT-TTF)4(H3O)Co(C2O4)3·C6H5Br represents the first example of a β″ phase for the tris(oxalato)cobaltate anion, but this salt does not show superconductivity.

A new Ni(dmit)2-based organic magnetic charge-transfer (CT) salt, (m-PO-CONH-N-methylpyridinium)[Ni(dmit)2]·CH3CN, where PO = 2,2,5,5-Tetramethyl-3-pyrrolin-1-oxyl free radical and dmit = 2-Thioxo-1,3-dithiole-4,5-dithiolate, was obtained, the crystal structure and magnetic properties of which are reported. Magnetic susceptibility of the CT salt obeys a combination of 1D ferromagnetic (1DF) Heisenberg (J1DF = +0.26 K) and Singlet-Triplet (ST) models (JST = -51.2 K) with mean field (MF) approximation (JMF = -6.7 K), suggesting that spins on the PO radicals form 1D ferromagnetic chains and spins on the Ni(dmit)2 monoanions forms spin dimers at low temperature, the latter of which was also confirmed by band calculations.

A new molecular superconductor, β”-(BEDTTTF)2[(H2O)(NH4)2Cr(C2O4)3].18-crown-6, has been synthesized from the organic donor molecule BEDT-TTF with the anion Cr(C2O4)3 3- . The crystal structure consists of conducting organic layers of BEDT-TTF molecules which adopt the β” packing motif (layer A), layers of NH4 + and Λ-Cr(C2O4)3 3- (layer B), layers of (H2O)(NH4)18- crown-6 (layer C), and layers of NH4 + and Δ-Cr(C2O4)3 3- (layer D) which produce a superstructure with a repeating pattern of ABCDABCDA. As a result of this packing arrangement this is the 2D superconductor with the widest gap between conducting layers where only a single donor packing motif is present (β”). Superconducting critical temperatures at ambient pressure observed by electrical transport and magnetic measurements are 4.0- 4.9 and 2.5 K, respectively. The strong 2D nature of this system, the broad transition to Tzero at 1.8K, and the transition of α of V ∝ Iα from 1 to 3 on I-V curves strongly suggests that the superconducting transition is very close to a Kosterlitz-Thouless transition. The magnetic field dependence of the superconducting critical temperature parallel to the conducting plane gives an upper critical field μ0Hc2// > 8 T, which is over the calculated Pauli-Clogston limit for this material.

A new BEDT-TTF-based salt with an organic free radical, α′-α′-(BEDT-TTF)2(PO-CONH-m-C6H4SO3)·H2O, has been prepared. The crystal structure consists of alternating donor and anion/water layers propagated along the c axis. The anisotropic radical anions form a head-to-head arrangement, which provides a permanent dipole moment. The effect on the nearest donor layer has been estimated to be 4.0 V. The salt has two crystallographically independent donor layers (A and B), one of which (A) is surrounded by the negative ends of the anion layer dipole whereas the B layers are bordered by the positive ends of the dipole. This structural feature suggests that layers A and B have different Fermi levels. To eliminate the imbalance, self-doping occurs whereby electron density is transferred from layer A to B. The temperature dependence of the magnetic susceptibility has 11.1% of extra Curie spins, from which a doping ratio of 12.7% has been estimated.

This work describes the synthesis of two novel functionalised 2,6-bis(pyrazol-1-yl)pyridine (bpp) ligands, namely 2,6-bis(pyrazol-1-yl)pyridine-4-carbothioamide (bppCSNH2) and N-methyl-2,6-bis(pyrazol-1-yl)pyridine-4-carbothioamide (bppCSNHMe). The corresponding solvated or non-solvated Fe(II) salts, [Fe(bppCSNH2)2]X2 and [Fe(bppCSNHMe)2]X2 (X = BF4− or ClO4−) were synthesised and their properties measured by SQUID magnetometry, Evans NMR, differential scanning calorimetry and single crystal X-ray diffraction. In the solid state [Fe(bppCSNH2)2]2+ salts persist in the low spin state below 350 K. The structure of [Fe(bppCSNH2)2](BF4)2·2MeNO2 shows a network of intermolecular interactions responsible for the low spin state stabilisation, relative to the prototypical [Fe(bpp)2]2+ spin crossover (SCO) salts. By contrast the complexes of bppCSNHMe both display abrupt SCO above 300 K. [Fe(bppCSNHMe)2](BF4)2·MeNO2 requires solvent loss before SCO can be observed centred at 332 K. The non-solvated [Fe(bppCSNHMe)2](ClO4)2 shows SCO centred at 325 K. Analysis of solvated and non-solvated crystal structures suggests that cooperativity is facilitated by thioamide-group interactions with neighbouring pyrazolyl and pyridyl moieties.

A new family of six paramagnetic metals, namely, κ-(BDH-TTP)4CoCl4·(H2O)5 (I), κ-(BDH-TTP)4Co0.54Mn0.46Cl4·(H2O)5 (II), κ-(BDH-TTP)4MnCl4·(H2O)5 (III), κ⊥-(BDH-TTP)4CoBr4·(CH2Cl2) (IV), κ⊥-(BDH-TTP)4MnBr4·(CH2Cl2) (V), and κ⊥-(BDH-TTP)4MnBr4·(CH2Br2) (VI), has been synthesized and characterized by X-ray crystallography, four-probe conductivity measurements, SQUID magnetometry, and calculations of electronic structure. The newly discovered κ⊥-type packing motif of organic layers differs from the parent κ-type by a series of longitudinal shifts of BDH-TTP radical cations in the crystal structure. Salts I–VI form two isostructural groups: I–III (κ) and IV–VI (κ⊥). Salts I–III are isostructural to the previously discovered κ-(BDH-TTP)2FeIIIX4 (X = Cl, Br) even though the charge of FeX4– anions is half that of the MX42– (M = Co, Mn) anions. The tetrahedral anions are disordered in I–III but completely ordered in IV–VI. The type of included solvent molecule is solely determined by the anion size. The paramagnet...

The synthesis, crystal structure and resistivity of a new semiconducting BEDT-TTF radical-cation salt containing the tris(oxalato)germanate(IV) anion is reported. BEDT-TTF 4 [Ge(C 2 O 4 ) 3 ].0.5dichloromethane crystallizes in the space group P 2 1 / c, a = 18.322(7), b = 11.919(4), c = 32.746(11) A, β = 105.797(5)°, V = 6881(4) A 3 , T = 295(1) K, Z = 4. Electrical resistivity measurements show that BEDT-TTF 4 [Ge(C 2 O 4 ) 3 ].0.5dichloromethane is a semiconductor with an activation energy of 0.224 eV and room temperature resistivity of 212 Ω cm.

In order to develop a kind of dual redox system with rechargeable battery property having potential high charge density, eight disulfide compounds carrying nitroxide radical have been prepared. Reflecting their multi-redox nature observed in their cyclic voltammetry data, they exhibit multi-step charge–discharge profiles with fairly large capacities over 200 Ah kg−1 for the first discharging processes. The Curie–Weiss type behaviors or 1D Heisenberg type profiles found for the respective radical compounds could be understandable by investigating the clarified crystal structures of four compounds (3, 4, 7, and 8) among them.

This article reports a family of new radical-cation salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with tris(oxalato)rhodate: three salts with the formula β′′-(BEDT-TTF)4[(cation)Rh(C2O4)3]·solvent (solvent = fluorobenzene, chlorobenzene, or bromobenzene) and one with the formula pseudo-κ-(BEDT-TTF)4[(NH4)Rh(C2O4)3]·benzonitrile. We report here the syntheses, crystal structures, electrical properties and Raman spectroscopy of these new molecular conductors. The bromobenzene salt shows a decrease in resistivity below 2.5 K indicative of a superconducting transition and a Shubnikov–de Haas oscillation with a frequency of 232 T and effective mass m* of 1.27me.

The new chiral TTF-based donor molecule bis(2-hydroxypropylthio)ethylenedithiotetrathiafulvalene has produced enantiopure R,R and S,S radical cation salts with the tetrafluoroborate anion as well as the nearly isostructural meso/racemate mixture. The enantiopure R,R or S,S salts are both 1:1 semiconducting salts with activation energies of 0.19–0.24 eV, both crystallising in the orthorhombic space group C2221. The semiconducting salt containing both meso and racemic donor cations has a very similar crystal structure but crystallising in the monoclinic space group C2/c (β = 91.39°) with similar S⋯S interactions but a smaller activation energy of 0.15–0.17 eV. This is in contrast to previous families of this type where the disordered racemate has a larger activation energy than its enantiopure salts.

A series of aryl-substituted naphthalenediimide derivatives that contain nitroxide radicals were prepared and their crystal structures were elucidated. Much stronger charge-transfer interactions were present in the derivatives with perfluorobenzene substituents than those with phenyl or 4-fluorophenyl substituents. These interactions result in the formation of single-component charge-transfer complexes by self-assembly of the naphthalenediimide derivatives to provide black crystals. As a consequence, the naphthalenediimide derivatives with perfluorobenzene substituents have better field-effect transistor (FET) properties than the other derivatives.

Several ferrocene derivatives (1–6) carrying nitroxide radical were prepared as dual redox compounds. They have distorted molecular structures and exhibit oxidation potentials based on both ferrocene and nitroxide groups except 4. The multi-step charge–discharge processes are discriminated for mono-substituted derivatives with the first discharge capacity up to 400 Ah kg−1 for imino-derivative 3, while relatively characterless profiles are observed for bis-substituted derivatives 4 and 6 with capacity over 300 Ah kg−1.

We have prepared new organic anionic acceptors, Br2XQNHCH2SO3− (2: X=Br, 3: X=BryCl1−y (y≈0.5), 4: X=Cl; Q=1,4-benzoquinone), that possess both an electron acceptor part (1,4-benzoquinone) and an anionic part (sulfonate). The reduction potentials of the PPh4 salts of 2, 3 and 4 are −0.45, −0.45 and −0.46 V (vs. SCE in CH3CN), respectively. The results indicate that they are weaker acceptors than chloranil (−0.13 V) and bromanil (−0.12 V). Each anionic acceptor (AA) provided two BEDT-TTF salts, β-(ET)5(AA)2·DCE·zH2O and λ-(ET)2(AA)·CH3OH (AA=2, 3, or 4; z=2: 0.97, 3: 0.83 and 4: 0.40). The structures and transport properties of the salts are reported.

The synthesis, crystal structure, and conducting properties of two new BEDT-TTF charge-transfer salts containing tris(oxalato)germanate(IV) anions are described. (BEDT-TTF)5[Ge(C2O4)3]2 (1) crystal...

Series of radical salts derived from a 2,4,6-triphenylpyridinium (TPP) carrying TEMPO-substituent and transition metal complexes were prepared by the anion exchange of the TPP–TEMPO tetrafluoroborate with [n-Bu4N][Ni(dmit)2], [n-Bu4N]2[Pd(dmit)2], [n-Bu4N]2[Pt(dmit)2], [n-Bu4N][Ni(mnt)2], or [n-Bu4N]2[Ni(mnt)2] to give crystals with different structural features. While weak antiferromagnetic interactions of the Curie–Weiss behavior of S = 1/2 spin are predominantly observed in the salts of Pd(dmit)2, Pt(dmit)2 and Ni(mnt)2, the magnetic behavior of 1:1 Ni(dmit)2 salt can be explained by the additional contribution from the spins on Ni(dmit)2 anions (χ − χTEMPO), obeying the 2D Heisenberg model. A couple of the oxidized salts, [TPP][Ni(dmit)2] as well as [TPP]2[Pd(dmit)2], exhibit semi-conducting properties with relatively high room temperature conductivities.

We have prepared a novel organic anionic weak acceptor, 2-aminomethylsulfo-3,5,6-trichloro-1,4-benzoquinone (1), as a PPh4 salt. Cyclic voltammetry indicates that its reduction potential is 0.53 V lower than that of chloranil. Electrocrystallisation with BEDT-TTF gave two salts, β - β -(BEDT-TTF)2(1)⋅0.5H2O (2) and β ″ - (BEDT-TTF)2(1)⋅CH3OH (3). Their crystal structures and physical properties are reported.

Three kinds of molecular complexes based on tetrathiafulvalene (TTF) and dialkylviologens were prepared and their crystal structures elucidated. While TTF-dimethylviologen complex forms a mixed stack arrangement of donors and acceptors in its crystal structure, TTF donors aggregate with long alkyl groups by CH/π and/or van der Waals interactions in a couple of TTF-heptylviologen complexes. Keywords: Molecular complex; CT complex; TTF; viologen; crystal structure Introduction Considerable attention has recently been paid in the field of supramolecular and materials chemistry to the incorporation of electroactive components into supramolecular assemblies. Among them, the supramolecular and macrocyclic assemblies derived from redox-controllable TTF 1 and dialkyl-4,4’-bipyridinium dications (dialkylviologens) such as 2 , have evoked attention, not only as catenanes and rotaxanes, but also as molecular switche s and potential molecular el ectronics devices [1]. The assembly of such kinds of molecular complexes relies strongly upon non-covalent charge-transfer (CT) interactions between donors and acceptors [2]. Since a dialkylviolgen

Series of organic biradical compounds 3a–3h consisting of a mesogenic core (biphenyl, naphthalene, azobenzene and azoxybenzene) and long alkoxy groups with PROXYL or TEMPO radicals were prepared. The TEMPO derivatives (3b, 3d, 3f, and 3h) were found to show fairly large antiferromagnetic interactions (J = −34 ∼ −45 K) being well expressed by singlet-triplet model irrespective of the mesogenic cores and the behavior is understandable by taking a hand-in-hand like assembled structure into consideration. On the other hand, only weak antiferromagnetic interactions with Curie–Weiss behavior were observed in all of the PROXYL derivatives (3a, 3c, 3e, and 3d) affording a sharp contrast with the TEMPO-based biradicals. Copyright © 2006 John Wiley & Sons, Ltd.

We have prepared eight TEMPO-containing anions TEMPO – A – CO – ( n - ) C 6 H 4 S O 3 - (n = o, m, p for A = NH (N1, N2, N3), n = o, p for A = NCH3 (M1, M3), and n = o, m, p for A = O (O1, O2, O3)) as PPh4 salts. Metathesis of their salts with (TTF)3(BF4)2 gave their TTF salts. Electrocrystallization of BEDT-TTF with PPh4 · M1 yielded the α-(BEDT-TTF)3(M1)2 · 8H2O salt. We report their crystal structures, electrical resistivities, and magnetic properties. The relation between crystal structures and physical properties are discussed.

Five TEMPO-containing anions TEMPO - CONA ( CH 2 ) n SO 3 - (H0−, A = H, n = 0; H1−, A = H, n = 1; H2−, A = H, n = 2; H3−, A = H, n = 3; M2−, A = CH3, n = 2) have been prepared as PPh4 salts. So far three TTF salts ((TTF)(H1) · 2H2O, (TTF)(H2) · H2O, and (TTF)(M2) · 0.50H2O), one TMTSF salt ((TMTSF)(H1) · 2H2O · PhCl), and one BEDT-TTF salt (α-(BEDT-TTF)5(H1)2 · 6H2O) have been obtained. Their crystal structures, electrical resistivities, and magnetic properties are reported.

We report here four novel purely organic magnetic conductors containing common electron donors together with an organic anion including an organic free radical, (TTF)(TEMPO-NHCOCH 2 SO 3 )·0.5H 2 O ( 1 ), (TMTSF)(TEMPO-NHCOCH 2 SO 3 )·2H 2 O ( 2 ), (BEDT-TTF) 3 (TEMPO-NHCOCH 2 SO 3 ) 2 ·2H 2 O ( 3 ), and α-(BEDT-TTF) 3 (TEMPO-NHCOCH 2 SO 3 ) 2 ·6H 2 O ( 4 ). The TTF complex was prepared by metathesis of (TTF) 3 (BF 4 ) 2 and the PPh 4 salt of the anion ( 5 ). The other complexes were obtained by electrocrystallization of the corresponding donors with the salt 5 as an electrolyte. Crystal structures of 2–4 have been solved. The salts 1 and 2 show relatively high resistivities (>10 7 and 5 × 10 3 Ω·cm), whilst the BEDT-TTF salts 3 and 4 have rather low room temperature resistivities (1.2 and 5.1 Ω·cm) with small activation energies (0.041 and 0.050 eV). The magnetic behavior of complex 1 obeys the Curie-Weiss law ( C = 0.379 emu·K/mol and θ = −3.29 K) and those of the other complexes obey the 1-D Heisenberg model ( C / J = 0.366/−0.32 for 2 , 0.373/−0.81 for 3 , and 0.380 emu·K·mol −1 /+0.42 K for 4 ). The relationships between the crystal structures and the physical properties are discussed.

The TaF 6 and FeBr 4 salts of BDA-TTP [2,5-bis(1,3-dithian-2-ylidene)-l,3,4,6-tetrathiapentalene] have been prepared and characterized as β-(BDA-TIP) 2 TaF 6 and β-(BDA-TIP) 2 FeBr 4 , respectively. The crystal structure of β-(BDA-TTP) 2 TaF 6 is isostructural to those of the ambient-pressure superconductors β-(BDA-TTP) 2 X (X = SbF 6 , AsF 6 and PF 6 ), but this salt undergoes an Ml (metal-to-insulator) transition instead of a superconducting transition at ambient pressure. The β-(BDA-TTP) 2 FeBr 4 salt, which is isomorphous to the superconductors β-(BDA-TTP) 2 MCl 4 (M = Fe and Ga) under applied pressures, exhibits a phase transition near 170 K and antiferromagnetic ordering with the Neel temperature (T N ) of about 9.5 K at ambient pressure.

The synthesis of dihydrotetrathiafulvalene (DHTTF) donors and the preparation of their charge-transfer (CT) salts have been undertaken to develop new organic metals and superconductors. The molecular structures of methylenedithio-DHTTF (MDHT), 1,4-dioxane-2,3-diyldithio-DHTTF (DODHT), and methylmethylidenedithio-DHTTF (Me-MDHT) are secured by X-ray crystallographic analyses. These DHTTF donors provide CT salts characterized by a wide range of conducting behavior from semiconducting to metallic and superconducting. The crystal structures of CT salts from each category are described.

Three N-salicylideneamine derivatives bearing TEMPO (2,2,6,6-tetra- methyl-1-piperidinyloxy) substituents were prepared in order to study their structure and property relationships and to investigate the possibilities of the existence of heat and/or light responsive magnetic properties. Curie-Weiss behavior with weak ferromagnetic intermolecular spin-spin interactions was observed in one of the radicals, while antiferromagnetic interactions were predominant for the other radicals and the structure-property relationships were investigated for the radical compounds from their crystal structures obtained by X-ray analyses. Preliminary results of the examination of their responses towards light and heat are also described.

The preparation and magnetic properties of organic radical anion salts derived from styrylpyrylium derivatives 1a and 2a are described and compared to those of the corresponding photo-dimers. The magnetic properties of the radical anions for TCNQ salt 1b and TCNQF4 salt 1c are rather different, showing antiferromagnetic interactions based on the 1-D Heisenberg model in the former, and ferromagnetic interactions in the latter. This difference is considered to be a result of the fairly large difference in their crystal structures. A considerable change in the magnetic properties was found between the radical anion salts of monomers and the corresponding photo-dimers, in which magnetic susceptibilities are largely diminished.

Organic salts derived from the styrylpyrilium systems as well as anthracene derivatives with TEMPO substituents were prepared and their structures and properties, especially magnetic properties wer...

The study of three kinds of non-tetrathiafulvalene (TTF) donors, 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA), 2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene (BDH), and 2-(1,3-dithiolan-2-ylidene)-5-(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (DHDA), which contain the bis-fused 1,3-dithiole-2-ylidene unit instead of the TTF unit as a π-electron system, has been undertaken to develop new molecular-based organic superconductors, magnetic conductors, and organic metals. The BDA donor produces the superconducting SbF 6 , AsF 6 , and PF 6 salts. The κ-(BDH) 2 FeCl 4 salt is a paramagnetic organic metal stable down to 1.5 K, whereas β-(BDA) 2 FeCl 4 exhibits metallic conducting behavior with a sharp metal-to-insulator (MI) transition (T MI = 113K), and antiferromagnetic ordering with a Neel temperature of near 8.5 K. Several salts of DHDA, a hybrid of BDA and BDH, are found to be metallic.

A novel ferrocene-containing dianion, Fe(C5H4–CH(CH3)NHCOCH2SO3–)2 (1), has been prepared. The oxidation potential of the PPh4 salt is + 0.35 V (vs. SCE in PhCN), indicating that it is a stronger donor than TTF (tetrathiafulvalene) by + 0.03 V. The dianion provided a TTF salt, the structure and physical properties of which are reported.

Anthracene derivatives with several TEMPO radicals (2-4, 10) were prepared, and each photodimerization reaction was investigated. Although the photodimerization was unsuccessful in obtaining the dimers of anthracenes 2 and 3, which could be alternatively prepared in a stepwise manner, the photodimers of anthracenes 4 and 10 were available by the direct photoreaction. The dissociation reaction of the dimers proceeded well by heating them in solution to give the corresponding monomers in each case, and thus the reversible system could be constructed in the latter two systems. While no large difference was observed in their magnetic behaviors between the monomer/dimer pair of 4 and 8, an intriguing difference was found in the magnetic behaviors for the pair of 10 and 11 from ferromagnetic interactions in 10 to the variable magnetic interactions in 11 depending on the solvent molecules incorporated in the crystals.

A new π-electron donor, 2,5-bis(13-dithian-2-ylidene)-1,3,4,6-tetrathia-pentalene (BDA-TTP), which contains no tetrathiafulvalene (TTF) molecule, produces a series ambient-pressure superconductors β-(BDA-TTP) 2 X (X = SbF 6 - , AsF 6 - , and PF 6 - ), in which the values of intermolecular overlap integrals suggest loose donor packing motifs.

Series of biphenyl derivatives bearing TEMPO (2,2,6,6-tetramethyl-1-piperidinyloxy)-substituents on one hand and long alkyl- or alkoxy-substituent on the other hand have been prepared. Among them a mesogenic property has been found in a biphenyl derivative with N-methyl-amino-TEMPO-carboxamide-substituent having lamellar structure of the molecular arrangement to show local antiferromagnetic spin interactions.

A synthetic study of the dioxolane derivatives of methylenedithio(ethylenedithio)-tetrathiafulvalene (MET), bis(methylenedithio)tetrathiafulvalene (MT), and methylene-dithiotetrathiafulvalene, their dithiolane analogues, and the oxathiolane derivative of MET has been undertaken to explore new organic metals. A practically useful preparation of the biheterocycle-fused 1,3-dithiol-2-ones as building blocks for these dichalcogenolane-linked tetrathiafulvalene (TTF) donors has been realized via the newly developed BF 3 -promoted reactions. The effect of the additional linked dichalcogenolane ring on the electron-donating ability is investigated by cyclic voltammetry. An X-ray crystallographic analysis of the oxathiolane-linked MET reveals that its molecular structure is isostructural with that of its dithiolane analogue but not bulkier than that of its dioxolane analogue. Several of the present TTF donors have produced metallic charge-transfer materials, two of which are characterized by X-ray crystallography. In the crystal structure of the 7,7,8,8-tetracyanoquinodimethane complex of the dioxolane-linked MT that exhibits metallic-like behavior around room temperature, the donor molecules are stacked head-to-tail to form the dimers, which are connected by C-H…O hydrogen bonds. On the other hand, in the metallic AsF 6 salt of the dioxolane-linked MET stable down to 2.0 K, the donor molecules are stacked head-to-head to form two-dimensional sheets despite the dioxolane ring being perpendicularly attached to the MET molecule.

Investigations of the tetrathiafulvalene (TTF) derivatives extended by the [sgrave]-bond frameworks, such as saturated heterocycles (3–8) and alkyl groups (9), have been undertaken to explore new molecular-based organic metals. TTF donors with the periphery extended by the cis-fused dioxane ring (3) and by linkage of a dichalocogenolane or dioxane ring (4–6 or 7) produce metallic radical-cation salts. While radical-cation salts of the methylated TTF donor (9a) are semiconductive, the ClO4 and PF6 salts of the ethylated one (9b) exhibit metallic conducting behavior for compressed pellets. The crystal structure of the metallic (4)2AsF6 salt is also presented.

The heat capacity of the title compound has been measured below room temperature by adiabatic calorimetry. A structural phase transition and a glass transition, both probably related to the intramolecular crankshaft motion, were detected at 273 K and 250 K, respectively. The degree of charge transfer (CT) was determined from IR spectroscopy as approximately 0.2e−. Since the central CC moiety of the stilbene molecule has a significant density in the HOMO, the observation of the phase and glass transitions means that the part involved in the CT interaction reorients itself in the crystal lattice above the glass transition temperature.

SQUID magnetometry and transport measurements combined with crystal structure refinement have been used to examine the variation in superconducting properties (Tc and Meissner fraction) in the molecular superconductor β″-(BEDT-TTF)4[(H3O)Fe(C2O4)3]·C6H5CN on replacing the C6H5CN guest molecule with pyridine (C5H5N). Up to approximately 65% pyridine substitution there is only a small decrease in Tc and Meissner fraction but above that the superconductivity is suppressed.

© The Japan Society for Analytical Chemistry.The title compound, (C24H20P)(FeN2O2Cl2), was prepared by adapting of literature methods. It crystallizes in the tetragonal space group P4. The structure consists of one P(C6H5)4 cation and one Fe(NO)2Cl2 anion. The anion has one ordered NO group and one ordered Cl ligand. The other two ligands are disordered, such that one half of NO and a half of Cl are located at each position.

The title compound, Cs(3)[Cr(C(2)O(4))(3)].2H(2)O, has been synthesized for the first time and the spatial arrangement of the cations and anions is compared with those of the other members of the alkali metal series. The structure is built up of alternating layers of either the D or L enantiomers of [Cr(oxalate)(3)](3-). Of note is that the distribution of the [Cr(oxalate)(3)](3-) enantiomers in the Li(+), K(+) and Rb(+) tris(oxalato)chromates differs from those of the Na(+) and Cs(+) tris(oxalato)chromates, and also differs within the corresponding BEDT-TTF [bis(ethylenedithio)tetrathiafulvalene] conducting salts. The use of tris(oxalato)chromate anions in the crystal engineering of BEDT-TTF salts is discussed, wherein the salts can be paramagnetic superconductors, semiconductors or metallic proton conductors, depending on whether the counter-cation is NH(4)(+), H(3)O(+), Li(+), Na(+), K(+), Rb(+) or Cs(+). These materials can also be superconducting or semiconducting, depending on the spatial distribution of the D and L enantiomers of [Cr(oxalate)(3)](3-).

The synthesis of DHOT-TTP, in which one sulfur atom of BDH-TTP [2,5-bis(1,3-dithiolan-2-ylidene)-1,3,4,6-tetrathiapentalene] is substituted by oxygen, has been accomplished. The DHOT-TTP donor possesses a less planar molecular structure than BDH-TTP, and gives a metallic AuI 2 salt stable down to 1.4 K, the crystal structure of which is elucidated.

The title compound, (CHP)(CHNOS)CuI.0.34HO, was obtained by the slow evaporation of a solvent from an acetonitrile solution containing a mixture of (PPh)N,N'-disulfobenzoquinonediimine and CuI. The structure consists of a one-dimensional metal-organic framework of the dianion and CuI. The anionic chains are surrounded by relatively large counter-cations, and are thus well isolated from each other.

The preparation, crystal structure and physical properties of β-(BDA-TTP)2GaCl4 has been investigated; the salt exhibits superconductivity at 3.1 K (onset) under a hydrostatic pressure of 7.6 kbar.