摘要:

A novel π-conjugated Ru(II) dinuclear complex containing a new azobenzene-bridged bis(terpyridine) ligand was synthesized and its photochemical and electrochemical properties were investigated. The ligand underwent reversibletrans-cisphotoisomerization, whereas the Ru complex did not show such photoisomerization behavior. Cyclic voltammetry of the complex displayed a reversible one-step 2e−oxidation wave due to Ru(III)Ru(III)/Ru(II)Ru(II) and four le−reduction waves indicating the formation of mixed-valence states when the electrons are accumulated at the ligand-based orbitals.

ISSN:1058-725X    

DOI:10.1080/10587250008023525

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The internal magnetic field (Hn) at57Fe nucleus was investigated for the mixed crystals NBu4[Mn(II)Fe(III)xCr(III)1−x(ox)3] (x = 0.04–1.0) by using Mössbauer spectroscopy, where NBu4+= tetra(n-butyl)ammonium ion and ox2−= oxalate ion. The angle (Θ) betweenHnand the principal axis ofVZZwas observed to change from ∼50∼ to ∼10∼ with the decrease of thexvalue (VZZ= the principal component of the electric field gradient tensor): the plot of Θ againstxindicates that the Cr(III) spins in NBu4[Mn(II)Cr(III)(ox)3] are aligned along an axis almost perpendicular to the honeycomb layers consisting of an alternate array of Mn(II) and Cr(III) ions through ox2−ligands. The Θ values estimated for the57Fe nuclei in the bivalent and tervalent sites of NBu4[Fe(II)0.03Mn(II)0.97Fe(III)0.02Cr(III)0.98(ox)3] were similar to each other.

ISSN:1058-725X    

DOI:10.1080/10587250008023526

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The electronic features of bimetallocenes are discussed as possible candidates for ferroelectric magnets, based on the coexistence of a dipole moment and a magnetic spin in its mixed-valence state. The dielectric functions were demonstrated for biferrocenium salts. Some charge transfer complexes of biferrocenes with TCNQ derivatives were prepared and characterized.

ISSN:1058-725X    

DOI:10.1080/10587250008023527

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Biferrocenyl nitronyl nitroxide (1) was prepared and its X-ray structure was determined. Magnetic susceptibility measurements on1showed the presence of a weak antiferromagnetic interaction (θ = −2 K) in the solid state.

ISSN:1058-725X    

DOI:10.1080/10587250008023528

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Adsorption properties in nanoporous crystals, especially Zn(BDC) (BDC=1.4-benzenedicar-boxylate) crystal, were studied theoretically. For sorbed molecules N2and CO2were employed and gas adsorption isotherms were obtained. In addition, O2as S=1 magnetic radical species was also treated in order to study the magnetic properties. Magnetic interaction between O2pairs exists and these cooperation might run in the nanoporous cavity. These results lead new approach to arrangement of organic spin radical sources and it is found that nanoporous organic-metal crystals are useful for controlling their position and orientation.

ISSN:1058-725X    

DOI:10.1080/10587250008023529

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We study qualitative differences of excited states between a charge ordered state and a charge uniforn state. The excited states are calculated in the random phase approximation for the one-dimensional extended Hubbard model at quarter filling. In the charge ordered state, a dominant excitation in the current-current correlation function has no charge density modulation. A dominant excitation in the charge uniform state originates from crossing the dimerization gap and modulates the charge density.

ISSN:1058-725X    

DOI:10.1080/10587250008023530

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The ac-susceptibilities of the isostructural metal-orgnets magnets, MII(N(CN)2)2(M = Ni (1), Co (2) and Fe (3)) have been studied as a function of temperature and pressure. Large variation in behaviors has been observed: the transition temperature initially increases in all three compounds and at higher pressures that for (1) saturates, for (2) decreases and for (3) increases continuously. These behaviors are due to the competition between antiferromagnetic (t2g↔eg) and ferromagnetic (t2g↔ t2gand eg↔ eg) inteeractions to the most dominant exchange pathway, M—N≡C-N—M. A mechanism for the magnetic ordering is proposed.

ISSN:1058-725X    

DOI:10.1080/10587250008023531

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We report a magnetic investigation of the endohedral metallofullerene La@C82.(CS2)1.5. Firstly, pure La@CC82was prepared and isolated, then single crystals were grown by a slow evaporation method. The crystals were screened by x-ray diffraction measurements and the structure was confirmed to be a body centered cubic lattice a = 25.62Å with space group I-43d. Optical absorption measurement revealed the compound to be a localised insulating or semi-conducting with a band gap around 2500cm−1.

ISSN:1058-725X    

DOI:10.1080/10587250008023532

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:1058-725X    

DOI:10.1080/10587250008023494

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor