Porphyrin–trimethyl‐β‐cyclodextrin (TMe‐β‐CDx) complexes have pseudorotaxane structures in which two meso‐phenyl and/or ‐pyridyl moieties penetrate the upper rim of two TMe‐β‐CDx molecules. Porphyrin derivatives with one to three pyridyl moieties at meso positions formed complexes with TMe‐β‐CDx in which the penetration of the upper rim of the two TMe‐β‐CDxs by the pyridyl moieties was minimized. In contrast, in TMe‐β‐CDx complexes formed with porphyrin derivatives bearing two 2‐methoxyphenyl moieties and two pyridyl moieties, the pyridyl moieties penetrate the upper rim of the two molecules because steric hindrance prevents penetration by the 2‐methoxyphenyl moieties.

Structural, transport and magnetic properties of single-crystalline samples of a praseodymium-based cubic compound PrMgNi 4 were studied. The single-crystal X-ray structural analysis revealed that Mg atoms are substituted for the Pr atoms at the 4a site by 4.5%. The χ(T ) data follow the Curie-Weiss law with an effective moment for the Pr 3+ ion. The magnetic specific heat divided by temperature, C m /T , shows a broad maximum at around 3 K, which is reproduced by a two-level model with a ground state doublet. On cooling below 1 K, C m /T approaches a constant value, which behavior is reproduced by a random two-level model. The twofold degeneracy of the ground state is lifted by symmetry lowering due to the substituted Mg atoms for the Pr atoms or strong hybridizations between the 4 f 2 electron states and conduction bands, which hinders the long-range quadrupole order.Praseodymium-based cubic compounds with a 4 f 2 configuration have attracted much attention because a variety of phenomena manifest themselves at low temperatures. Pr-filled skutterudites exhibit correlated electronic phenomena due to strong hybridization between the 4 f electron and conduction electrons (cf hybridization), e.g., heavy-fermion superconductivity, a metal-insulator transition, and higher-order multipolar ordering.[1-4] These phenomena are attributed to the interplay between the conduction electrons and multipolar degrees of freedom in quasi-degenerated ground states of the Pr ions under the crystalline electric field (CEF).In case the CEF ground state is the non-Kramers doublet of the Pr ion under cubic symmetry, the magnetic dipole is quenched but electric quadrupole and magnetic octupole become active. Thereby, the multipoles in the non-Kramers doublet could govern the low-temperature properties. A typical system is PrPb 3 , which exhibits an antiferroquadrupole (AFQ) order at T Q = 0.4 K [5][6][7]. Below T Q , the quadrupoles are modulated sinusoidally by the correlation between the quadrupoles and the conduction electrons [8,9]. Another example is PrInNi 4 , which presents a ferromagnetic transition at T C = 0.75 K.[10-12] The nonmagnetic ground state doublet could mix with the excited magnetic triplet by the ferromagnetic exchange interaction inducing a magnetic moment in the ground state which orders ferromagnetically.On the contrary, PrAg 2 In and PrMg 3 exhibit no quadrupole order. [13][14][15] The absence of the quadrupole order was discussed by considering the Kondo effect due to strong c-f hybridization, because the specific heat divided by temperature, C/T , is largely enhanced at low temperatures. However, the thermoelectric power is not enhanced and the absolute value is comparable to that of the La counterpart, indicating the conduction electrons at the Fermi level could not correlate strongly with the 4 f 2 electrons. [16,17] Moreover, in the specific heat measurements using a high-quality single crystal of PrAg 2 In with the residual resistivity ratio of RRR = 14, a cusp-type anomaly manifests itself at 0.33 K, indic...

Background:Ellagitannins have attracted much attention because of the biological and pharmacological activities. In the total synthesis of ellagitannins, 3,4,5-tri-O-benzylgallic acid has been a key compound to introduce the protected galloyl group. From the perspective of coordination chemistry, 3,4,5-tri-O-benzylgallic acid is an interesting carboxylate ligand which might be capable of dinuclear carboxylate complex. Such a dinuclear carboxylate complex might be interesting as a new example of copper acetate type complexes.Objectives:The objective of the work is to synthesize a copper acetate type complex by using 3,4,5-tri-O-benzylgallic acid and to see a new feature of copper acetate compounds, by elucidating the crystal structure, magnetic property, and adsorption property for N2gas.Methods:Copper(II) 3,4,5-tri-O-benzylgallate has been synthesized by a reaction of 3,4,5-tri-O-benzylgallic acid and copper(II) nitrate at pH=9 condition. The isolated complex was characterized using single-crystal X-ray structure analysis, XRD analysis, UV-visible spectroscopy, IR spectroscopy, and temperature dependence of magnetic susceptibility.Results:The crystal structure shows a crystallographically centrosymmetric dinuclear molecule with four carboxylato-bridges and axial dimethylformamide molecules and crystal dmf molecules [Cu···Cu 2.6345(12) Å]. In the crystal, 1D supramolecular assembly by π-π interaction between the benzyl aromatic rings of dinuclear molecules was observed. Temperature dependence of magnetic susceptibilities showed a considerable antiferromagnetic interaction between the two copper(II) ions (2J = –214 cm–1). Type-II gas-adsorption property was observed for N2.Conclusion:A key-compound for the total synthesis of ellagitannins, 3,4,5-tri-O-benzylgallic acid (Htbng), was shown to be a new ligand for the synthesis of dinuclear copper acetate analogue with a lantern-type core, extending the realm of copper acetate clusters.

New allene compounds bearing 1,8‐diphenoxy or bis(3,5‐di‐tert‐butylphenyl) oxyacridene (diaryloxyacridene) moieties were synthesized. These compounds were more easily oxidized than Cl‐substituted compounds. The allene compounds were oxidized to generate thermally stable triplet carbenes. Electron spin resonance and electron spin transient nutation spectra of the oxidation reaction products suggested the generation of triplet species; however, the main isolated product from the 1,8‐diphenoxy allene was a cyclized compound that was characterized by X‐ray analysis. The product derived from diaryloxy allene was also characterized by X‐ray analysis as a singlet species, which included a vinyl cation stabilized by a neighboring O(3,5‐di‐tert‐butylphenyl) group. This singlet species was stable even at room temperature and did not show any electron spin resonance signals in solution, indicating that the triplet species was not in equilibrium with the singlet. Copyright © 2016 John Wiley & Sons, Ltd.

A brand-new self-folding biscavitand was synthesized from a feet-to-feet-connected bisresorcinarene. The X-ray crystal structure of the biscaivtand showed that the two cavities are tightly connected with four butylene linkages. The conformationally coupled two cavities accommodated two cationic guests, showing a homotropic negative cooperativity in nonpolar solvents (toluene and chloroform). A polar tetrahydrofuran solvent weakened the cyclic hydrogen bonding interactions of the biscavitand, which resulted in noncooperative guest binding.