High field magnetic resonant properties of beta'-(ET)2SF5CF2SO3

A systematic electron spin resonance (ESR) investigation of the low temperature regime for the (ET)2SF5CF2SO3 system was performed in the frequency range of ~200-700 GHz, using backward wave oscillator sources, and at fields up to 25 T. Newly acquired access to the high frequency and fields shows experimental ESR results in agreement with the nuclear magnetic resonance (NMR) investigation, revealing evidence that the transition seen at 20 K is not of conventional spin-Peierls order. A significant change of the spin resonance spectrum in beta'-(ET)2SF5CF2SO3 at low temperatures, indicates a transition into a three-dimensional-antiferromagnetic (3D AFM) phase.Comment: 4 pages, 7 figures, minor grammatical change

Charge Ordering in alpha-(BEDT-TTF)2I3 by synchrotron x-ray diffraction

The spatial charge arrangement of a typical quasi-two-dimensional organic conductor alpha-(BEDT-TTF)2I3 is revealed by single crystal structure analysis using synchrotron radiation. The results show that the horizontal stripe type structure, which was suggested by mean field theory, is established. We also find the charge disproportion above the metal-insulator transition temperature and a significant change in transfer integrals caused by the phase transition. Our result elucidates the insulating phase of this material as a 2k_F charge density localization.Comment: 8 pages, 5 figures, 1 tabl

Charge Order with Structural Distortion in Organic Conductors: Comparison between \theta-(ET)2RbZn(SCN)4 and \alpha-(ET)2I3

Charge ordering with structural distortion in quasi-two-dimensional organic conductors \theta-(ET)2RbZn(SCN)4 (ET=BEDT-TTF) and \alpha-(ET)2I3 is investigated theoretically. By using the Hartree-Fock approximation for an extended Hubbard model which includes both on-site and intersite Coulomb interactions together with Peierls-type electron-lattice couplings, we examine the role of lattice degrees of freedom on charge order. It is found that the experimentally observed, horizontal charge order is stabilized by lattice distortion in both compounds. In particular, the lattice effect is crucial to the realization of the charge order in \theta-(ET)2RbZn(SCN)4, while the peculiar band structure whose symmetry is lower than that of \theta-(ET)2RbZn(SCN)4 in the metallic phase is also an important factor in \alpha-(ET)2I3 together with the lattice distortion. For \alpha-(ET)2I3, we obtain a phase transition from a charge-disproportionated metallic phase to the horizontal charge order with lattice modulations, which is consistent with the latest X-ray experimental result.Comment: 10 pages, 13 figures, to appear in J. Phys. Soc. Jpn. Vol. 77 (2008) No.

N-Methylimidazole Promotes The Reaction Of Homophthalic Anhydride With Imines

The addition of N-methylimidazole (NMI) to the reaction of homophthalic anhydride with imines such as pyridine-3-carboxaldehyde-N-trifluoroethylimine (9) reduces the amount of elimination byproduct and improves the yield of the formal cycloadduct, tetrahydroisoquinolonic carboxylate 10. Carboxanilides of such compounds are of interest as potential antimalarial agents. A mechanism that rationalizes the role of NMI is proposed, and a gram-scale procedure for the synthesis and resolution of 10 is also described

Toward Crystal Design in Organic Conductors and Superconductors

We have seen that many different types of intermolecular interactions in organic conducting cation radical salts. Hydrogen bonding between the donor molecules and the anions is weak but not negligible. The ionic Madelung energy is insufficient to completely intersperse anions and cations, thus the layers favored by the van der Waals interactions remain intact. The search for new conducting and superconducting salts has been mainly by trial-and-error methods, even though simple substitutions have been employed in order to obtain isostructural analogs of successful (e.g., superconducting) salts. However, even seemingly minor substitutions sometimes destroy the packing type, and different crystal structures result. Simulations with the aim at predicting crystal structures have not succeeded, mainly because the different interaction types are of comparable energy, and the delocalized and partial charges render the calculations of the ionic terms extremely unreliable. Clearly, the development of suitable crystal modeling techniques with predictive capabilities is one of the great needs of the field

New type of polymeric indium tellurides: Low-temperature synthesis and structure characterization of [M(en)(3)]In2Te6 (M=Fe, Zn) and alpha- and beta-[Mo-3(en)(3)(mu(2)-Te-2)(3)(mu(3)-Te)(mu(3)-O)]In2Te6

Crystal growth of metal tellurides and tellurometalates employing solvothermal reactions at temperatures below 200 degrees C have resulted in four new indium tellurium phases, [Fe(en)(3)](In2Te6) (I), [Zn(en)(3)](In2Te6) (II), and alpha- and beta-[Mo-3(en)(3)(mu(2)-Te-2)(3)(mu(3)-Te)(mu(3)-O)]In2Te6 (III-alpha and III-beta). Single crystal X-ray diffraction analyses show that I and II are isostructural and belong to the orthorhombic crystal system, space group P2(1)2(1)2(1) (No. 19). Compound I: a = 11.654 (1) Angstrom, b = 12.968(2) Angstrom, c = 16.273(2) Angstrom, Z= 4. Compound II: a b = 12.948(2) Angstrom, c = 16.285(1) Angstrom, Z = 4. The two polymorphs III-alpha and III-beta crystallize in the monoclinic system. Compound III-alpha: a = 11.815(2) Angstrom, b = 21.769(3) Angstrom, c = 14.498(4) Angstrom, beta = 95.43(2)degrees, Z = 4, space group P2(1)/c (No. 14). Compound III-beta: a = 22.154(3) Angstrom, b = 11.550(2) Angstrom, c = 14.230(2) Angstrom, beta = 99.05(1)degrees, Z = 4, space group P2(1)/a (No. 14). All four are Zintl compounds containing novel one-dimensional polymeric chains of (1)(infinity)[(In2Te6)(2-)] that can be described as alternating fused five-membered rings [(In3+)(2)(Te2(2-))(Te2-)], joined at the In atoms