Single-component molecular conductor [Cu(tmdt)(2)] containing an antiferromagnetic Heisenberg chain.

Traditional molecular conductors are composed of more than two chemical species and are characterized by low-dimensional electronic band structures. By contrast, the single-component molecular metals [M(tmdt)(2)] (M = Ni, Pt, Au; tmdt = trimethylenetetrathiafulvalenedithiolate) possess three-dimensional electronic structures that can be widely tuned by exchanging the central transition metal atom (M). In this study, the Cu atom was used to realize a new magnetic single-component molecular conductor exhibiting strong pi-d interactions. The crystal structure of [Cu(tmdt)(2)] was found to be essentially the same as those of the Ni, Pt, or Au-based systems with metallic states down to low temperature, but different from the structure of [Cu(dmdt)(2)] (dmdt = dimethyltetrathiafulvalenedithiolate) with its tetrahedrally coordinated dmdt ligands. A compressed pellet of microcrystals exhibited fairly high room-temperature conductivity (sigma(RT) approximately 7 S.cm(-1)), which increased almost linearly with pressure, reaching 110 S.cm(-1) at 15 kbar. This strongly suggests that the single crystal of [Cu(tmdt)(2)] is metallic at high pressure. Magnetic susceptibility measurements indicated one-dimensional Heisenberg behavior with |J| = 117 cm(-1) and an antiferromagnetic transition at 13 K. Density functional theory molecular orbital calculations revealed that the alpha-spin orbital of pdsigma(-) is distributed at the central part of the complex (CuS(4)), and alpha- and beta-sym-Lpi orbitals have almost the same energies and their spins are distributed mainly in the pdsigma(-) orbital. This is in contrast to the first single-component molecular metal [Ni(tmdt)(2)], which has stable metal bands formed from an almost degenerated sym-Lpi orbital (the highest occupied molecular orbital) and asym-Lpi(d) orbital (the lowest unoccupied molecular orbital). These results suggest that the alpha-pdsigma(-) state of [Cu(tmdt)(2)] exists just around the Fermi energy of the virtual metal band formed from the asym-Lpi(d) and sym-Lpi states. Thus, as expected, [Cu(tmdt)(2)] is a non-trivial single-component molecular conductor with pi-d multifrontier orbitals. In addition, ((n)Bu(4)N)(2)[Cu(tmdt)(2)] was synthesized, and its crystal structure was determined. Its Curie behavior (chi(rt) = 1.2 x 10(-3) emu mol(-1); C = 0.36 emu.K mol(-1)) indicates the existence of an isolated S = 1/2 spin on each dianionic molecule.

Structural anomalies associated with antiferromagnetic transition of single-component molecular metal [Au(tmdt)2].

The crystal structure of the single-component molecular metal [Au(tmdt)(2)] was examined by performing powder X-ray diffraction experiments in the temperature range of 9-300 K using a synchrotron radiation source installed at SPring-8. The structural anomalies associated with antiferromagnetic transition were observed around the transition temperature (T(N) = 110 K). The continuous temperature dependence of the unit cell volume and the discontinuous change in the thermal expansion coefficient at T(N) suggested that the antiferromagnetic transition of [Au(tmdt)(2)] is a second-order transition. Au(tmdt)(2) molecules are closely packed in the (021) plane with two-dimensional lattice vectors of a and l (= 2a + b + 2c). The shortest intermolecular S...S distance along the a axis shows a sharp decrease at around T(N), while the temperature dependence of l exhibits a characteristic peak in the same temperature region. A distinct structure anomaly was not observed along the direction perpendicular to the (021) plane. These results suggest that the molecular arrangement in only the (021) plane changes significantly at T(N). Thus, the intermolecular spacing shows anomalous temperature dependence at around T(N) only along that direction where the neighboring tmdt ligands have opposite spins in the antiferromagnetic spin structure model recently derived from ab initio band structure calculations. The results of single-crystal four-probe resistance measurements on extremely small crystals (approximately 25 microm) did not show a distinct resistance anomaly at T(N). The resistance anomaly associated with antiferromagnetic transition, if at all present, is very small. The Au-S bond length decreases sharply at around 110 K; this is consistent with the proposed antiferromagnetic spin distribution model, where the left and right ligands of the same molecule possess opposite spin polarizations. The tendency of the Au-S bond to elongate with decreasing temperature is ascribed to the small energy gap between the pd sigma(-) (or SOMO + 1) and the asym-Lpi(d) (or SOMO) states of the Au(tmdt)(2) molecule.

High-pressure (up to 10.7 GPa) crystal structure of single-component molecular metal [Au(tmdt)2].

The crystal structure of the single-component molecular metal [Au(tmdt)(2)] was examined at pressures up to 10.7 GPa in order to examine whether the high-pressure structure reflects the crystal's metallic nature. Crystal structure analyses were performed at 0.2, 0.8, 1.3, 3.0, 5.5, and 10.7 GPa on the basis of the powder X-ray diffraction data obtained by using the synchrotron radiation source SPring-8. The unit cell volume at 10.7 GPa was approximately 75% of the initial volume, indicating that [Au(tmdt)(2)] is a 'soft material' like a typical molecular crystal in spite of its metallic nature. The pressure dependences of the bond lengths of the Au(tmdt)(2) molecule were found to be approximately 1 order of magnitude smaller than those of the intermolecular atomic distances. These results seem to justify the commonly accepted conjecture that the molecule usually behaves almost like a rigid body up to a fairly high pressure. It was found that the anisotropy of the lattice compression of the insulating I(2) crystal below 20 GPa can be essentially interpreted on the basis of a very simple 'interatomic repulsion model', which assumes that the molecules in the crystal are packed such that as far as possible, an increase in the interatomic repulsions between neighboring molecules is avoided. However, the maximum decrease in the intermolecular distance in [Au(tmdt)(2)] was observed along the a direction although there were many intermolecular S...S contacts shorter than the van der Waals distance (3.70 A) along this direction. The shortest intermolecular S...S distance was 2.73 A at 10.7 GPa, which is approximately 1 A shorter than the S...S van der Waals distance (3.70 A). The crystal lattice of [Au(tmdt)(2)] is considered to be stabilized by the enhancement of the intermolecular overlapping of the conduction molecular orbitals having large amplitudes on peripheral S atoms. Although the crystal is composed of 'isolated molecules' like a typical insulating molecular crystal, its compressibility behavior seems to reflect its metallic nature.

Electrical properties of new organic conductor (BEST)(2)InBr(4) [BEST = bis(ethylenediseleno)tetrathiafulvalene] up to 10.8 GPa and antiferromagnetic transition of (BEST)(2)FeBr(4).

A new organic conductor, (BEST)(2)InBr(4), with alternating donor layer arrangement has been synthesized, and the electrical properties have been investigated up to 10.8 GPa. The temperature dependence of the high-pressure resistivity shows a complicated metal-semiconductor transition behavior. The room temperature resistivity decreases with pressure up to 8.6 GPa but increases at higher pressures. The magnetic susceptibility of an isostructural (BEST)(2)FeBr(4) salt shows an antiferromagnetic transition at 4.4 K, which is suppressed with increasing magnetic field.

Evidence of the chemical uniaxial strain effect on electrical conductivity in the spin-crossover conducting molecular system: [Fe(III)(qnal)2][Pd(dmit)2]5.acetone.

A novel spin-crossover molecular conductor, [Fe(qnal)2][Pd(dmit)2]5.acetone, was prepared and characterized. The crystal structural analyses of both the low- and high-temperature phases revealed that the supramolecular pi-pi interactions between the spin-crossover Fe(qnal)2 cations as well as the cation contraction play an important role in the uniaxial lattice deformation which will modulate the electrical conductivity of the conducting Pd(dmit)2 layer.

Electrical resistivity of tetramethyltetratelluronaphtalene crystal at very high pressures - examination of the condition of metallization of pi molecular crystal.

Four-probe resistivity measurements were performed on the TMTTeN crystal by using a diamond anvil high-pressure cell up to 30 GPa. The crystal could not be metallized though the room-temperature resistivity decreased to a very small value (1.5 x 10-3 Omega cm). Although single-component molecular metals are composed of molecules, the pressure-induced metallization of a single-component pi molecular crystal while maintaining the initial molecular structure appears to be very difficult.

Conducting dimerized cobalt complexes with tetrathiafulvalene dithiolate ligands.

To obtain novel single-component molecular metals, we attempted to synthesize several cobalt complexes coordinated by TTF (tetrathiafulvalene)-type dithiolate ligands. We succeeded in the syntheses and structure determinations of ((n)Bu(4)N)(2)[Co(chdt)(2)](2) (1), ((n)Bu(4)N)(2)[Co(dmdt)(2)](2) (2), [Co(dmdt)(2)](2) (3), and [Co(dt)(2)](2) (4) (chdt = cyclohexeno-TTF-dithiolate, dmdt = dimethyl-TTF-dithiolate, and dt = TTF-dithiolate). Structure analyses of complexes 1-4 revealed that two monomeric [Co(ligand)2]- or [Co(ligand)(2)](0) units are connected by two Co-S bonds resulting in dimeric [Co(ligand)(2)](2)(2-) or [Co(ligand)(2)](2) molecules. Complex 1 has a cation-anion-intermingled structure and exhibited Curie-Weiss magnetic behavior with a large Curie constant (C = 2.02 K x emu x mol(-1)) and weak antiferromagnetic interactions (theta = -8.3 K). Complex 2 also has a cation-anion-intermingled structure. However, the dimeric molecules are completely isolated by cations. Complexes 3 and 4 are single-component molecular crystals. The molecules of complex 3 form two-dimensional molecular stacking layers and exhibit a room-temperature conductivity of sigmart = 1.2 x 10(-2) S.cm(-1) and an activation energy of E(a) = 85 meV. The magnetic behavior is almost consistent with Curie-Weiss law, where the Curie constant and Weiss temperature are 8.7 x 10(-2) K x emu x mol(-1) and -0.85 K, respectively. Complex 4 has a rare chair form of the dimeric structure. The electrical conductivity was fairly large (sigmart = 19 S.cm(-1)), and its temperature dependence was very small (sigma(0.55K)/sigma(rt) = ca. 1:10), although the measurements were performed on the compressed pellet sample. Complex 4 showed an almost constant paramagnetic susceptibility (chi(300) (K) = 3.5 x 10(-4) emu x mol(-1)) from 300 to 50 K. The band structure calculation of complex 4 suggested the metallic nature of the system. Complex 4 is a novel single-component molecular conductor with a dimeric molecular structure and essentially metallic properties down to very low temperatures.

Ferroelectric porous molecular crystal, [Mn3(HCOO)6](C2H5OH), exhibiting ferrimagnetic transition.

A porous molecular crystal with guest ethanol molecules, [Mn3(HCOO)6](C2H5OH), was found to be a new type of multifunctional molecular system, which exhibits a ferroelectric transition at 165 K and a ferrimagnetic transition at 8.5 K. [Mn3(HCOO)6](C2H5OH) will give a hint to design "multiferroic" molecular materials where ferroelectric and ferromagnetic orders coexist.

Electrical conductivity modulation coupled to a high-spin-low-spin conversion in the molecular system [FeIII(qsal)2][Ni(dmit)2]3.CH3CN.H2O.

The synergy between the electrical conductivity within the stacks of Ni(dmit)2 in the newly electrocrystallized [Fe(qsal)2][Ni(dmit)2]3.CH3CN.H2O and the spin conversion of Fe(qsal)2 is evidenced. In addition, the presence of a light-induced excited spin state trapping effect suggests that this complex is a prototypal photoswitchable spin-crossover molecular conductor.

Hybrid organic-inorganic conductor with a magnetic chain anion: kappa-BETS2[Fe(III)(C2O4)Cl2] [BETS = bis(ethylenedithio)tetraselenafulvalene].

The synthesis, crystal structure, and electrical, optical, and magnetic properties of kappa-BETS2[Fe(III)(C2O4)Cl2], where BETS is bis(ethylenedithio)tetraselenafulvalene, are reported. The black plate crystals consist of parallel donor layers, two per unit cell, displaying a kappa-type packing of BETS(0.5+) within the bc plane and anionic magnetic chains, [Fe(C2O4)Cl2-]n, running along the c axis. It displays metallic behavior down to 4.2 K, and analysis of the optical reflectivity data gives unscreened plasma energies of 0.69 eV (E parallel c) and 0.40 eV (E perpendicular c). The optical anisotropy is larger than that seen for other kappa phases and is described well by transfer integrals obtained from extended Hückel calculations. However, the transfer integrals need to be scaled down uniformly by a factor of 1.21 to reproduce the absolute experimental plasma frequencies. The band structure consists of a one-dimensional (1D) band and a hole pocket, characteristics of kappa phases. The magnetic properties were modeled by the sum of a 1D antiferromagnetic chain contribution from the d spins of Fe3+, a temperature-independent paramagnetic contribution, and a Curie impurity term. At 4.5 K, there is a signature of long-range magnetic ordering to a canted-antiferromagnetic state in the zero-field-cooled-field-cooled magnetizations, and at 2 K, a small hysteresis loop is observed.

[A case of postoperative recurrent lung cancer with chronic renal failure and respiratory failure successfully treated with gefitinib].

We administered gefitinib to a patient after considering his request to be treated with the drug. Fortunately, he responded favorably to the treatment and did not show signs of serious adverse effects or deterioration of renal functions. The patient was a 69-year-old male who visited an outpatient clinic because of chronic renal failure and was diagnosed with primary lung cancer. He then underwent an operation for lung cancer, but because it had progressed to stage IV the lesion was not completely resected. The patient was unable to receive effective chemotherapy due to the prior chronic renal failure. During best support care, the patient suffered from respiratory failure due to the tumor growth, and his quality of life (QOL) deteriorated. The patient was administered 250 mg of gefitinib orally, which was effective in reducing the tumor, improving his QOL, and prolonging his survival time. With the lack of literature on administering gefitinib to patients with chronic renal failure and evidence supporting the effectiveness of this treatment, the physician in charge should obtain the patient's informed consent before initiating treatment using this anticancer drug.

Observation of three-dimensional fermi surfaces in a single-component molecular metal, [Ni(tmdt)2].

Rigorous evidence of metallicity of a molecular crystal consisting of single-component neutral molecules is disclosed by observing the Fermi surface through magnetic quantum oscillations. Torque magnetometry measurements of de Haas-van Alphen oscillatory signals in a single crystal of [Ni(tmdt)2] molecules (tmdt = trimethylenetetrathiafulvalenedithiolate) were performed by using a sensitive microcantilever at low temperatures in high magnetic fields to 45 T. The observed signals for all directions of magnetic field revealed unambiguously the presence of three-dimensional Fermi surfaces for both holes and electrons. The results are consistent with electronic band structure calculations for [Ni(tmdt)2].

Infrared electronic absorption in a single-component molecular metal.

The infrared spectra of the crystal of transition metal complex molecules with extended-TTF ligands, Ni(tmdt)2, which is the first single-component molecular metal that has a stable metallic state even at low temperatures, exhibited an extremely low-energy electronic absorption around 2200 cm-1 (tmdt = trimethylenetetrathiafulvalenedithiolate). The systematic shift of the absorption peaks for molecules similar to Ni(tmdt)2, which range from metallic to semiconducting crystals, shows that the single-component molecular conductors are composed of molecules with unprecedentedly small HOMO-LUMO gaps.

[Clinico-statistical analysis of renal cell carcinomas in patients on hemodialysis].

Eleven patients on hemodialysis that were surgically treated for renal cell carcinomas during the recent 10 years at our institutes were clinically analyzed. Patients' ages at presentation ranged from 35 to 70 years with an average of 54.8 years. Nine of the 11 patients were males and 2 were females. Periods between the introduction of hemodialysis and the presentation ranged from 1 to 21 years with an average of 11.7 years. The most frequent cause of hemodialysis was chronic glomerulonephritis. Five patients presented with macroscopic hematuria, which was the most frequent clinical manifestation. Transperitoneal nephrectomy through a lumbar oblique incision was performed in 9 of 12 surgical procedures. Transperitoneal resection and retroperitoneal endoscopic resection were performed on 2 patients and 1 patient, respectively. Blood transfusion was performed on 2 patients with retroperitoneal hemorrhage before or after operation and 2 patients with pre-existing renal anemia. Pathologically, 9 patients had pT1a disease. Patients were followed up for up to 7 years and 11 months. One patient died of the disease and 2 patients died of unknown causes. In conclusion, surgical removal of renal cell carcinomas was well tolerated, safe and effective treatment in patients under hemodialysis.