摘要:

Assembled metal complexes, where organic π electrons and metal d electrons coexist, form one important class of materials in the field of molecular “metals” and “superconductors”. Among them, molecular conductors based on metal-dithiolene complexes are known to exhibit various conducting properties. Recent studies on molecular conductors based on the acceptor-type Pd(dmit)2[dmit=2-thioxo-1,3-dithiol-4,5-dithiolate] and the donor-type Ni(edo)2[edo = ethylenedioxydithiolate] and related materials are described.

ISSN:1058-725X    

DOI:10.1080/10587250008023495

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The synthesis and the magnetic characterization of new layered compounds of formula Cr[NH3(CH2)2PO3(Cl)], Fe[C6H5PO3]·H2O and Fe2[O3P-(CH2)2-PO3]·2H2O is presented. The compounds order antiferromagnetically at the critical temperature TN, which is at 4.9K for the first one, at 21.5K for the second and at 24K for the third one. Below TN, they all behave as aweak ferromagnet.

ISSN:1058-725X    

DOI:10.1080/10587250008023496

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Metal cluster complexes with interesting magnetic properties characteristic of nanoscale magnetic particles have become an attractive prospect in the last few years. These complexes exhibit magnetization hysteresis loops and out-of-phase ac magnetic susceptibility signals. The advantages of such clusters over fragmented bulk ferromagnets are their easy synthesis and manipulation, their high solubility, and their potential use in storing a large density of information. Here we will focus our attention on the family of several distorted Mn4cubane molecules with a [MnIVMnIII3O3X]6+core, tetranuclear vanadium (III) complexes with a butterfly structure and dodecanuclear manganese complexes, [Mn12O12(O2CR)16(H2O)4] (where R can be an aliphatic or aromatic group) and their corresponding singly reduced salts [Mn12O12(O2CR)16(H2O)4] (PPh4), which have been extensively studied in our laboratories.

ISSN:1058-725X    

DOI:10.1080/10587250008023497

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Co(η5-C5H5)(C8H4S8), Ti(η5-C5H5)2(C8H4S8)2], [NMe4][Ti(η5−C5H5)(C8H4S8)2], and [NMe4] [Zr(η5−C5H5)(C8−H4S8)2] [C8H4S82−= 2−{(4,5-ethylenedithio)−1,3-dithiole-2-ylidene}−1,3-dit hiole−4,5-dithiolate(2−)] were prepared. They exhibited low oxidation potentials [−0.23 − +0.45 V (vs.SCE)] for the C8H4S8ligand oxidation and were oxidized by iodine or 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) to afford [Co(η5-C5H5)−(C8H4S8)] (I3), [Ti(η5-C5H5)2(C8H4S8)](I3), [Ti(η5-C5H5)−(C8H4S8)2](I3)0.3, [Ti(η5−C5H5) (C8H4S8)2] (TCNQ)0.3, and [Zr−(η5-C5H5)(C8H4S8)2]. These oxidized species showed electrical conductivities of 0.19 − 1.0 × 10−4S cm−1at room temperature for compacted pellets.

ISSN:1058-725X    

DOI:10.1080/10587250008023498

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Characteristic luminescence from the assembled species of [Pt(CN)2(L)] (L = 3,3′-biisoquinoline (i-biq) and 2,2′-bipyridine (bpy)) has been found in a dilute EtOH-MeOH (4:1 v/v) glassy solution at 77 K. For thei-biq complex, a broad emission band (λmax= 680 nm) appears with increasing concentration in addition to a3ππ*emission band form the monomer complex (λmax= 528 nm). The broad band is attributable to the emission from the3MLCT state of the assembled species with the Pt-Pt intermolecular interaction. In the case of the bpy complex, similar broad emission is also observed as well as the sharp3ππ*emission. However, the broad emission has an excimeric character. The π-π interaction between the π-conjugated ligands would be an important factor in the assemblage of the platinum complexes in the dilute system.

ISSN:1058-725X    

DOI:10.1080/10587250008023499

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We found the giant negative magnetoresistance in the one-dimensional π-dsystem TPP[Fe(Pc)(CN)2]2below 50K. The large negative magnetoresistance was observed for the field along thea-axis, while the small one along thec-axis. We also observed the anisotropic Curie behavior of the magnetic susceptibility. The large (small) magnetoresistance was observed in the field orientation for the large (small) magnetic susceptibility. The reduction of the spin-flip scattering of the itinerant electrons by the local moments under the magnetic field was proposed as the origin of the negative magnetoresistance. In the isostructural compound TPP[Co(Pc)(CN)2]2we observed the large positive magnetoresistance. This positive magnetoresistance cannot be explained in terms of the orbital effects under the field.

ISSN:1058-725X    

DOI:10.1080/10587250008023500

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Ground state phase diagrams of the MMX chains are studied in a one-dimensional dimerized 3/4-filled model by exactly diagonalizing 12-site clusters. Experimentally observed phases are reproduced by changing relative strengths of an electron-lattice coupling, the inter-dimer transfer integral, and an elastic constant whose variation is roughly estimated from the interatomic spacing, the species of the halogen ions and the presence/absence of counter ions.

ISSN:1058-725X    

DOI:10.1080/10587250008023501

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Second-harmonic generation (SHG) properties of the hybrid-films of a clay and [δ-Ru (4,7-diphenyl-1,10-phenanthroline)3](ClO4)2(δ-Ru(dpp)3), which was found to be stable enough over a very long time, were studied. The ratio of the SHG signal intensity between Z-and Y-Type films of δ-Ru(dpp)3has been compared. Furthermore, the SHG coefficientd33at 1.06 μm is determined as 30 pm/V for the Y-Type hybrid-film of δ-Ru(dpp)3.

ISSN:1058-725X    

DOI:10.1080/10587250008023502

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Several gold(III) complexes with TTF dithiolato ligands have been prepared as the tetrahexylammonium salts. The cyclic voltammograms in DMF showed two or three pairs of redox waves. X-Ray structure analysis of Ph4P·Au(eodt)2·(DMF)2reveals that the Au(eodt)2anion takes a significantly folded chair conformation. Charge-transfer salts of Au(dt)2derivatives with TCNQ showed high conductivity (σrt= 100−101S cm−1on a compressed pellet).

ISSN:1058-725X    

DOI:10.1080/10587250008023503

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

LIESST iron(II) spin-crossover mononuclear complex [Fe(L)(CN)2]·H2O (1) (L is Schiff-base macrocyclic ligand derived from the condensation of 2,6-diacetylpyridine with 3,6-dioxaoctane-1,8- diamine) with macro ring and two CN−bridging ligands was used as optically switchable molecular building blocks. Since the bidentate CN−ligands in complex1can coordinate to other metal compounds, it is possible to build one-dimensional molecular-based photo-magnets. We have synthesized [Fe(L)(CN)2][Mn(hfac)2] (2) and investigated it by using magnetic susceptibility, Mössbauer spectra and IR spectra mesurements. The complex2exhibits spin-crossover behavior (T1/2=110 K) on the moieties of the iron sites.

ISSN:1058-725X    

DOI:10.1080/10587250008023504

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor