Experimental realization of Lieb-Mattis plateau in a quantum spin chain.

Topological properties in material science have recently received tremendous attention, as exemplified by topological insulators. As for quantum spin systems, the Haldane chain with integer spins is the best known example. The realization of a topological quantum phase in the Haldane chain is an innovative research development related to the 2016 Nobel Prize in Physics.

Triplet Diradical-Cation Salts Consisting of the Phenothiazine Radical Cation and a Nitronyl Nitroxide.

The spin-spin and magnetic properties of two (nitronyl nitroxide)-(di-p-anisylamine-phenothiazine) diradical cation salts, (DAA-PTZ) -NN⋅MBr (M=Ga, Fe), have been investigated. These diradical-cation species were prepared by the cross-coupling of iodophenothiazine DAA-PTZ-I with NN-AuPPh followed by oxidation with the thianthrenium radical cation (TA ⋅MBr ). These salts were found to be highly stable under aerobic conditions.

Randomness-induced quantum spin liquid on honeycomb lattice.

Quantum entanglement in magnetic materials is expected to yield a quantum spin liquid (QSL), in which strong quantum fluctuations prevent magnetic ordering even at zero temperature. This topic has been one of the primary focuses of condensed-matter science since Anderson first proposed the resonating valence bond state in a certain spin-1/2 frustrated magnet in 1973. Since then, several candidate materials featuring frustration, such as triangular and kagome lattices, have been reported to exhibit liquid-like behavior.

Cyclic Triradicals Composed of Iminonitroxide-Gold(I) with Intramolecular Ferromagnetic Interactions.

A triangular gold(iminonitroxide-2-ide) trimer complex (5) was prepared and investigated to determine its magnetic properties. The results showed that the metalloid triradical is highly stable, even in solution under aerated conditions. The intramolecular exchange interaction of 5 was found to be positive (Jintra /kB ≈+29 K), thus showing that 5 is in a quartet ground state.

Experimental Realization of a Quantum Pentagonal Lattice.

Geometric frustration, in which competing interactions give rise to degenerate ground states, potentially induces various exotic quantum phenomena in magnetic materials. Minimal models comprising triangular units, such as triangular and Kagome lattices, have been investigated for decades to realize novel quantum phases, such as quantum spin liquid. A pentagon is the second-minimal elementary unit for geometric frustration.

(Nitronyl nitroxide)-substituted trioxytriphenylamine radical cation tetrachlorogallate salt: a 2p-electron-based weak ferromagnet composed of a triplet diradical cation.

The synthesis and the solid state magnetic properties of (nitronyl nitroxide)-substituted trioxytriphenylamine radical cation tetrachlorogallate, NNTOT(+)⋅GaCl(4)(-), are reported. In the temperature region between 300 and 3 K, the magnetic behavior is characterized by the strong intramolecular ferromagnetic interaction (J/k(B)=+400 K) between the radical (NN) and the radical cation (TOT(+)) and the weak intermolecular antiferromagnetic interaction (J/k(B)=-1.9 K) between NNTOT(+) ions.

Synthesis and properties of oxo-carboxylato- and dioxo-bridged diosmium complexes of tris(2-pyridylmethyl)amine.

A series of oxo-bridged diosmium complexes with tpa ligand (tpa = tris(2-pyridylmethyl)amine) are synthesized. The hydrolytic reaction of the mononuclear osmium complex [Os(III)Cl(2)(tpa)]PF(6) in aqueous solution containing a sodium carboxylate yields a μ-oxo-μ-carboxylato-diosmium(III) complex, [Os(III)(2)(μ-O)(μ-RCOO)(tpa)(2)](PF(6))(3) (R = C(3)H(7) (1), CH(3) (2), or C(6)H(5) (3)). One-electron oxidation of 1 with (NH(4))(2)Ce(IV)(NO(3))(6) gives a mixed-valent [Os(III)Os(IV)(μ-O)(μ-C(3)H(7)COO)(tpa)(2)](PF(6))(4) complex (4).

A new ferrimagnet based on a radical-substituted radical cation salt.

Radical-substituted radical cations are attractive spin building blocks of molecule-based magnets. The introduction of an additional spin as a counteranion provides a unique three-spin system wherein the magnetic interactions between the spins of the radical substituent and the radical cation (J(intra)) and those between the spins of the radical cation and the anion (J(inter)) play decisive roles in determining the magnetic properties of the system. We report the first demonstration of a ferrimagnet by utilizing a large-J(intra) system, nitronyl nitroxide-substituted dihydrophenazine radical cation (NNDPP(*+)) in combination with tetrabromoferrate (FeBr(4)(-)) as the counteranion.

Diiron amido-imido complex [(CpFe)2(mu2-NHPh)(mu2-NPh)]: synthesis and a net hydrogen atom abstraction reaction to form a bis(imido) complex.

A reaction between [CpFeCl]x and LiNHPh (1 equiv to Fe) produces a new paramagnetic Fe(II)-Fe(III) mu2-amido-mu2-imido complex [(CpFe)2(mu2-NHPh)(mu2-NPh)] (1), which, upon interaction with 2,2'-azobis(2,4-dimethylvaleronitrile), undergoes a net N-H hydrogen atom abstraction reaction to give a diamagnetic Fe(III)-Fe(III) mu2-imido dimer [CpFe(mu2-NPh)]2 (2). The molecular structures of 1 and 2 have been determined by single-crystal X-ray diffraction.

Molecular rotor of Cs2([18]crown-6)3 in the solid state coupled with the magnetism of [Ni(dmit)2].

Nanoscale molecular rotors that can be driven in the solid state have been realized in Cs2([18]crown-6)3[Ni(dmit)2]2 crystals. To provide interactions between the molecular motion of the rotor and the electronic system, [Ni(dmit)2]- ions, which bear one S=1/2 spin on each molecule, were introduced into the crystal. Rotation of the [18]crown-6 molecules within a Cs2([18]crown-6)3 supramolecule above 220 K was confirmed using X-ray diffraction, NMR, and specific heat measurements.

Design of novel inorganic-organic hybrid materials based on iron-chloranilate mononuclear complexes: characteristics of hydrogen-bond-supported layers toward the intercalation of guests.

Novel intercalation compounds constructed from the common two-dimensional hydrogen-bond-supported layers and functional guests [(H(0.5)phz)(2)[Fe(CA)(2)(H(2)O)(2)].2H(2)O](n)(1), ([Fe(Cp)(2)][Fe(CA)(2)(H(2)O)(2)])(n)(2), ([Fe(Cp*)(2)][Fe(CA)(2)(H(2)O)(2)])(n)(3), and [(TTF)(2)[Fe(CA)(2)(H(2)O)(2)]](n)(4) (H(2)CA = chloranilic acid, phz = phenazine, [Fe(Cp)(2)] = ferrocene, [Fe(Cp*)(2)] = decamethylferrocene, TTF = tetrathiafulvalene) are described.