Tris(l, 2-benzodithio)- and tris(l, 2-ethylenedithio)-trimethylenemethane dication salts were synthesized for the purpose of using as an acceptor in the formation of charge-transfer (CT) complexes with some dianionic donors. In the CT complexes of these dications with hexacyanotrimethylenecyclopropane and tetrafluorotetracyanoquinodimethane dianions, in which the CT degree is albeit small, the spin-spin interaction between the cation radical and the anion radical was antiferro magnetic in the temperature range of 60–293 K, but changed to a ferromagnetic one in the lower temperature range till 15 K, the lowest temperature used in this experiment. This provides the first demonstration of ferromagnetic spin-spin interaction in purely organic/molecular CT complexes. It is conceivable that the ferromagnetic spin-spin interaction is caused by a“spin polarization”mechanism rather than a“CT configurational mixing”mechanism.

Transition to a ferromagnetic long range ordered state was found at 0.60 K in the orthorhombic β-phase crystal of p-nitrophenyl nitronyl nitroxide (or 2-(4′-nitrophenyl)-4, 4, 5, 5-tetramethyl-4, 5-dihydro-lH-imidazol-1-oxyl-3-N-oxide in the IUPAC nomenclature). This finding provides the first example of an organic bulk ferromagnet consisting of light elements and having a definite molecular and crystal structure.

Several phenoxy radicals were chemically modified in order to probe the intermolecular spin interactions between these radicals. Based on the ketenimine chemistry, we demonstrated an efficient synthetic sequence for the preparation of new dicyano substituted hindered phenols. A series of new polar group substituted nitroxide-nitroxyl radicals were also synthesized. These radicals with polar functionalities include 3, 5-dinitro-phenyl, 3, 5-dimethoxyphenyl, 3, 5-dihydroxyphenyl, 4-hydroxyphenyl, 4-cyanophenyl, 3, 5-dicyano-phenyl, and 3, 5-di-i-butyl-4-hydroxyphenyl derivatives of 4, 4, 5, 5-tetramethylimidazolidine-3-oxide-1-oxyl. They are intended for the study of functional substitution effects on the nature of spin exchanges in solid state.

The title monomer diacetylene with α-nitronyl nitroxide as pendants was synthesized and polymerized by heating in vacuum. The magnetic properties of the polymer were studied, and it was found that this organic polymer showed weak ferromagnetism.

The poly(4'-vinylphenoxy) nonconjugated polyradical was generated by photolysis of an oxalate-functionalized poly(4-hydroxystyrene). Spin-counting experiments in the electron spin resonance spectrum (ESR) showed efficient production of radicals with g = 2.0041, consistent with the expected pendant phenoxyl radicals. The thermal behavior of the ESR signal intensity indicated through-space antiferromagnetic coupling of the pendant radicals. The similarity of the behavior of this nonconjugated system to that of nominally conjugated polyradical systems synthesized by others suggests that geometric effects leading to deconjugation may be a major consideration in the synthesis of organic ferromagnetically exchange coupled polyradicals.

The magnetic susceptibility data in the temperature range of 4.2 K up to 300 K in the crystalline state of a metal lomesogen containing a Cu(II)-center are reported and discussed. Also magnetic properties of a Cu(II) containing chemically modified polymethylmethacrylate are presented. The interpretation of data, based on the Curie-Weiss-equation, shows a negative Weiss constant in the range up to θ = −27 K. An intermolecular long range antiferromagnetic exchange interaction at least in the solid or amorphous state has been discussed.

Several new examples of ferro- and antiferromagnetic organometallic and coordinated compounds have been investigated by means of the temperature-dependent magnetic measurements and Mössbauer spectroscopy. Above 70 K the Cu3 [Fe(CN)6] 2-4H2O compound is ferromagnetic as it obeys the Curie-Weiss experession, χm= C/(T-θ), with θ = 25 K; μeff evalued at 200 K is 4.91 μβ. Below 20 K this compound displays the onset of spontaneous magnetization in zero applied field. Above 10 K the Cu[(bpy>2] 3 [Fe(CN)6] 2.5H2O is also ferromagnetic (θ= 2.5 K). Above 20 K the antiferromagnetic [Fe(C5H4Me)2] + [TCNOJ- (θ= 3.25 K) and [Fe(C5H4Me)2]+[TCNE]- (θ= -3.64 K) obey the Curie-Weiss expression. The e.p.r. and Mössbauer spectra for these compounds have been discussed.

The syntheses and physical properties of K-(ET)2CU[N(CN)2]X (X = Br and Cl) are summarized. The K-(ET)2Cu [N(CN)2] Br salt is the highest Tc radical-cation based ambient pressure organic superconductor (Tc = 11.6 K), and the K-(ET)2CU [N(CN)2] C1 salt becomes a superconductor at even higher Tc under 0.3 kbar hydrostatic pressure (Tc = 12.8 K). The similarities and differences between K-(ET)2Cu[N(CN)2]Br and K-(ET)2CU(NCS)2 (TC = 10.4 K) are presented. The X-ray structures at 127 K reveal that the S-S contacts shorten between ET dimers in the former compound while the S-S contacts shorten within dimers in the latter. The differences in their ESR linewidth behavior is also explained in terms of the structural differences. A semiconducting compound, (ET)Cu[N(CN)2]2, isolated during K-(ET)2Cu[N(CN)2]Cl synthesis is also reported. The ESR measurements of the K-(ET)2Cu[N(CN)2]Cl salt indicate that the phase transition near 40 K is similar to the spin density wave transition in (TMTSF)2SbF6. A new class of organic superconductors, K-(ET)2CU2(CN)3 and K-(ET)2Cu2(CN)3.δBrδ, is reported with Tc's of 2.8 K (1.5 kbar) and 2.6 K (1 kbar), respectively.

A close examination of the relation between Tc and structural characteristics of BEDT-TTF superconductors has revealed that there is a good correlation between the effective volume (VeffαVc-Vanion and Tc but no such correlation between the unit cell volume (Vc) and Tc. In order to increase Veff, it is favorable to use big but thin anion which can form a thin two-dimensional anion layer. Three-dimensional donor interactions are critical to have sizable Tc. According to the designing, two new superconductors; K-(BEDT-TTF)2CuCN[N(CN)2] (Tc=11.2K) and K'-(BEDT-TTF)2Cu2(CN)3 (Tc=3.8K), are prepared and their physical and structural properties are described. Their Tc's are discussed in terms of veff.

The superconducting transition under magnetic field for organic superconductors к-(BEDT-TTF)2 Cu(NCS)2 and к-(BEDT-TTFh)2 Cu[N(CN)2]Br has been analyzed by employing fluctuation renormal-ization theory. From magnetization measurements the interlayer and intralayer Ginzburg-Landau coherence lengths are determined. The effect of the isotope substitution to BEDT-TTF molecules has been studied. The result for resistive measurements is also described.

We have synthesized cooper(I)di[bis(ethylenedithiolo)terathiafulvalene] bis(isothiocyanato), [(BEDT-TTF)2]+[Cu(NCS)2]using standard electrochemical methods. Single crystal samples of the compound were obtained and were found to have superconducting transition temperatures of 10.4 K, using DC conductivity measurements. [(BEDT-TTF)2 +[Cu(NCS)2] shows a region between room temperature and 90 K which appears to be“semiconducting”

To characterize the structure of the samples we used Scanning Tunneling Microscopy (STM). STM supplied real-space images of the sample surface in accordance to its electronic structure. Ravy observed diffuse streaks between Bragg spots in his X-ray data of [(BEDT-TTF)2 +[Cu(NCS)2]−, which he attributes to a stacking fault at every fourth repetition of the anion in the crystal structure [1]. STM shows no evidence for such disorder in [−(BEDT-TTF)2]+[Cu(NCS)2]−of the type proposed, and in fact illustrates direct evidence to the contrary. An intensity modulation in the STM data supports the possibility of a charge density wave commensurate with the lattice. This interpretation is consistent with the calculated Fermi surface which allows nesting of the wave vector and may explain the peculiar behavior of the temperature dependency of the conductivity data in the normal region.

The electrical properties of cation-radical salts based on S, S-DMBEDT-TTF and their crystal structures are presented.

Observations of Shubnikov-de Haas(SdH) and de Haas-van Alphen(dHvA) oscillations in organic metals (BEDT-TTF)2X, with X=KHg(SCN)4, θ-I3 and β″-AuBr2. are reported. In KHg(SCN)4 salt, in addition to the SdH oscillations with fundamental frequency of 670 T corresponding to about 16% of the first Brillouin zone(FBZ), we observed splitting of each SdH peak which we ascribed to “spin-splitting” We have also found that the ground state of this salt is not a simple metal but has some magnetic character. In θ-l3 salt we have succeeded in an observation of dHvA oscillations for the first time. We observed a “saw-tooth” dHvA oscillation characteristic to a highly two-dimensional and extraordinary clean electronic system. In addition to the fundamental frequency of 4170 T corresponding to 50.4 % of the FBZ and its higher harmonics, we observed an oscillation with lower frequency of 730 T corresponding to about 8.8 % of the FBZ. A new Fermi surface topology for θ-l3 salt is proposed based on the analysis of the dHvA effect. In β″-AuBr2, we observed complex dHvA oscillations, which can be explained in terms of the mixing of two fundamental frequencies of 47 and 268 T, suggesting the presence of very small pockets corresponding to 0.6 and 2.9 % of the FBZ.

Methods for preparation of thetraheterafulvalenes containig O, S, Se, N as additional he-teroatoms and some of their conducting products are described. Also, results concerning stoichi-ometry, structures, and physical properteis are briefly discussed.

The 1:1 charge transfer salt of dimethyltetrathiotetracene (DMTTT) and of tetracyanoethylene (TCNE), C26H12N4S4 crystallizes from chlorobenzene in the monoclinic system, space group P2(l)/c with cell constants a = 11.136(2), b = 11.254(3), C = 17.280(4) A, beta = 96.56(2), V = 2151.4(9) A, Z = 4 and dcalc = 1.57 0 mg/nun. The structure is made up of dimers of DMTTT and TCNE, respectively. Polycrystalline samples of DMTTT/TCNE exhibit a weak paramagnetism which was studied by ESR techniques from 102 to 293 K. The ESR studies reveal anisotropie spectra which are best resolved in the temperature range 102 to 250 K. The spectra observed are those expected from a spin system which is described by an orthorhombic g-tensor. The isotropie g-value calculated from the observed anisotropie g-tensors falls between the isotropie g-values for DMTTT and TCNE. As the temperature is increased, the spectral width decreases suggesting motion of and/or an increase in the spin concentration. DMTTT/TCNE is a relatively poor electrical conductor which is consistent with its crystal structure.

Conducting and superconducting salts based on bis(ethylenedithio)tetrathiafulvalene, ehtylenedithioselenatrithiafulvalene, ethylenedioxyethylenedithiotetrathiafulvalene, and ethylenedioxyvinylenedithiotetrathiafulvalene were prepared and studied.

1, 4-Bis [2-(tetrathiafulvalen-2-yl)ethenyl] -2, 5-dimethylbenzene (BTFE-DMB) is synthesized and its structure is found to be planar. The single crystal of its iodine salts undergoes a metal-insulator transition about 180K. The compaction pellets of the iodine salts show the current dependent resistive anomaly under high pressure.

Tetrathiafulvalene and bis(ethylenedithio)tetrathiaful-valene radical-cation salts of the a-Keggin anion [PMo12O40] have been synthesized and characterized. They both are mixed-valence compounds and contain the paramagnetic anion [PMO12O40] 4-. The former contains irregular TTF ϱ+ chains isolated by the inorganic anions. From the IR spectrum a ϱ=+0.5 is suggested. The latter is two-dimensional, where BEDT-TTF molecules are ionised, ϱ=+0.5, and arranged in irregular chains. They show electrical conductivity typical of organic semiconductors.

Porphyrin thin films were deposited by ionized cluster beam from a source material of tetraphenylporphyrin iron(III) chloride. It was found that the chlorine atoms are mostly removed from the original molecules during the film formation process, resulting in a film of tetraphenylporphyrin iron(II) complex. The film is chemically active and showed reversible reaction with O2 and CO gases at an elevated temperature. The formation of μ-oxo dimera, which hinders the chemical activity, was not observed. Electrical conductivity of the film was also measured under various atmosphere.

In order to obtain desired switching and memory properties by carrying out chemical modifications on CuTCNQ-type charge-transfer complexes, systematic explorations on various donor and acceptor reactivities are necessary. Thus, the reactivities of thirty-three different metals with TCNQ and four organo-acceptors with Cu in an CH3CN solution were qualitatively studied, as well as the solvent effects on the complex film formation. Uniform coverage of Metallo-organic complex films were obtained (in the order of reactivities) on TCNQ complexes of Tl, Ca, Mg, Cu, Ag, Mn and Cd, as well as on Cu complexes of TCNQ(OET)2, BTCNQ and TCNQ(i-Pr)2. The donor reactivity is affected by its surface immunity (behavior) towards the acceptor attack and the solubility of the formed charge-transfer complex in the chosen solvent. The acceptor reactivity is affected mainly by a steric effect, followed by an inductive effect of the substituents. The complex film morphology and quality could be optimized by matching the relative reactivity of donor vs. acceptor and by choosing the appropriate solvent with proper solubility of the formed complex.