Shinya Takaishi

We synthesized a new porous coordination polymer Cu[Cu(pdt)2], which shows relatively high electrical conductivity (6 x 10(-4) S cm(-1) at 300 K) by the introduction of electron donors and acceptors as building units. This compound is applicable as a porous electrode with high power density. In addition, this compound forms a triangular spin lattice and shows spin frustration.

Using recently reported robust porphyrinic metal–organic framework (RPM) materials, we have examined the systematic exchange of pillaring linkers/struts as a means of accessing new versions of these materials. Dipyridyl-porphyrin Zn(II) (Zn-dipy) struts were successfully replaced by M2-dipy (M2 = 2H(+), Al(III), Sn(IV)), forming crystalline solid solutions of Zn(Zn1−xMx)-RPM in variable ratios. In addition, post-synthetic metallation was demonstrated using Zn2H-RPM, again with retention of cryst

A -Pd(III)-Br-Pd(III)-Mott-Hubbard state was observed in a quasi-one-dimensional bromo-bridged Pd compound [Pd(en)2Br](C5-Y)2 x H2O (en = ethylenediamine, C5-Y = dipentylsulfosuccinate) for the first time. The phase transition between Mott-Hubbard and charge-density-wave states occurred at 206 +/- 2 K and was confirmed by using X-ray, ESR, Raman and electronic spectroscopies, electrical resistivity, and heat capacity. From X-ray powder diffraction patterns and Raman spectra of a series of Pd-Br

81Br Nuclear quadrupole resonance (NQR) measurement was performed in an S = 1/2 one-dimensional Heisenberg antiferromagnetic metal complex [NiBr(chxn)2]Br2 (chxn: 1R,2R-diaminocyclohexane), having a halogen-bridged MX chain structure -Br-Ni3+-Br-Ni3+-Br-. Two 81Br NQR signals were observed below 40 K, while a single signal was observed above 130 K, showing the presence of two nonequivalent bridging Br sites below 40 K. This NQR result together with previously reported magnetic susceptibility and

State secrets: Mott–Hubbard and charge-density-wave states have been observed in the quasi-1D bromine-bridged Ni and Pd complexes [M(chxn)2Br]Br2, respectively, using STM (see image for the Ni complex, the arrow denotes the direction of the chain). The spin soliton was also visualized in real space in the Ni-Pd mixed-metal complexes for the first time. chxn: (1R,2R)-diaminocyclohexane.

Redox-active metal-organic frameworks (MOFs) have great potential for use as cathode materials in lithium-ion batteries (LIBs) with large capacities because the organic ligands can undergo multiple-electron redox processes. However, most MOFs are electrical insulators, limiting their application as electrode materials. Here, we report an electron-conductive MOF with a 2,5-dihydroxy-1,4-benzoquinone (dhbq) ligand, Fe(dhbq). This compound had an electrical conductivity of 5 × 10^-6 S cm<

In spite of a long history of quasi-one-dimensional halogen-bridged complexes (MX-chains), all Pt and Pd complexes form the charge-density wave (CDW) state (-X...M(II)...X-M(IV)-X...), while all Ni complexes form Mott-Hubbard (MH) states (-X-Ni(III)-X-Ni(III)-X-), without exception. We have succeeded in stabilizing the Pd(iii) MH state for the first time by utilizing the following two methods: partial substitution with Ni(iii) ions, [Ni(1-x)Pd(x)(chxn)(2)Br]Br(2), and chemical pressure via long

A new molecule, 1,3,6,8-tetramethylpyrene (TMPY), with a similar shape to the luminescent material perylene has been successfully synthesized. The co-crystals with perylene doping have been grown and their crystal structure has been clarified by X-ray analysis. Optical spectra indicate that effective energy transfer has been achieved in the doping systems and the luminescence efficiency has reached as high as 78%. The pure TMPY shows p-type characteristics during the FET operation. The hole mobi

We synthesized a novel iodo-bridged linear chain platinum compound, having the quasi-two-dimensional charge-density-wave (CDW) ground state and the smallest band gap. In this compound, we discovered an anomalous valence state in the boundary region at which the CDW phase alternates in the crystal by means of ESR, X-ray diffuse scattering, STM, and electrical resistivity. This anomalous state can be explained by the fast fluctuation between Pt(IV)-I...Pt(II) and Pt(II)...I-Pt(IV) in the double we

A new bromo-bridged Ni III compound has been synthesized. This compound displayed a strong antiferromagnetic interaction between spins located on Ni III species (J=(2350+/-500) K) that result from the strong covalency of the Ni--Br bond and the spin-Peierls transition below 150 K. This was shown by the results of magnetic susceptibility and 81Br nuclear quadrupole resonance spectroscopy analysis. We succeeded in the electrostatic carrier doping of a single crystalline sample by using a field-eff