Physical properties of quasi-one-dimensional charge-transfer metal complexes;[M(HBQD)2]TCNQ (M=Ni, Pd; H2BQD=1,2-benzoquinonedioxime)

Kagami, Yuka; Iwahori, Fumiyasu; Ohishi, T.; Hama, Takeo; Manabe, T.; Yamashita, Masahiro; Kitagawa, Hiroshi; Sakai, Keita; Mitani, Tadaoki

doi:10.1016/s0379-6779(97)80911-3

Cited by 4 publications

(1 citation statement)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Further, the XPS of complexes 2b and 5 showed similar values of Pd 3d 3/2 at 343.0 and 343.1 eV and 3d 5/2 at 331.7 and 337.8 eV, respectively (Figure ), and their XANES gave similar spectra, again indicating that the complexes have the metal center with a very similar oxidation state. The 3d 3/2 and 3d 5/2 XPS values are dependent on the oxidation state of the Pd ion, and a large difference between the Pd(II) and Pd(IV) complexes has been reported . Since the differences in the XPS values between 2b and 5 were very small, the oxidation state of the Pd ion in complex 5 was concluded to be the +2 state.…”

Section: Resultsmentioning

confidence: 99%

Syntheses and Electronic Structures of One-Electron-Oxidized Group 10 Metal(II)−(Disalicylidene)diamine Complexes (Metal = Ni, Pd, Pt)

et al. 2007

View full text Add to dashboard Cite

Group 10 metal(II) complexes of H2tbu-salen (H2tbu-salen = N,N'-bis(3',5'-di-tert-butylsalicylidene)ethylenediamine) and H2tbu-salcn (H2tbu-salcn = N,N'-bis(3',5'-di-tert-butylsalicylidene)-1,2-cyclohexanediamine) containing two 2,4-di(tert-butyl)phenol moieties, [Ni(tbu-salen)] (1a), [Ni(tbu-salcn)] (1b), [Pd(tbu-salen)] (2a), [Pd(tbu-salcn)] (2b), and [Pt(tbu-salen)] (3), were prepared and structurally characterized by X-ray diffraction, and the electronic structures of their one-electron-oxidized species were established by spectroscopic and electrochemical methods. All the complexes have a mononuclear structure with two phenolate oxygens coordinated in a very similar square-planar geometry. These complexes exhibited similar absorption spectra in CH2Cl2, indicating that they all have a similar structure in solution. Cyclic voltammograms of the complexes showed a quasi-reversible redox wave at E1/2 = 0.82-1.05 V (vs Ag/AgCl), corresponding to formation of the relatively stable one-electron-oxidized species. The electrochemically oxidized or Ce(IV)-oxidized species of 1a, 2a, and 3 displayed a first-order decay with a half-life of 83, 20, and 148 min at -20 degrees C, respectively. Ni(II) complexes 1a and 1b were converted to the phenoxyl radicals upon one-electron oxidation in CH2Cl2 above -80 degrees C and to the Ni(III)-phenolate species below -120 degrees C. The temperature-dependent conversion was reversible with the Ni(III)-phenolate ground state and was found to be a valence tautomerism governed by the solvent. One-electron-oxidized 1b was isolated as [Ni(tbu-salcn)]NO3 (4) having the Ni(II)-phenoxyl radical ground state. One-electron-oxidized species of the Pd(II) complexes 2a and 2b were different from those of the Ni(II) complexes, the Pd(II)-phenoxyl radical species being the ground state in CH2Cl2 in the range 5-300 K. The one-electron-oxidized form of 2b, [Pd(tbu-salcn)]NO3 (5), which was isolated as a dark green powder, was found to be a Pd(II)-phenoxyl radical complex. On the other hand, the ESR spectrum of the one-electron-oxidized species of Pt(II) complex 3 exhibited a temperature-independent large g anisotropy in CH2Cl2 below -80 degrees C, while its resonance Raman spectrum at -60 degrees C displayed nu8a of the phenoxyl radical band at 1600 cm-1. These results indicated that the ground state of the Pt(II)-phenoxyl radical species has a large distribution of the radical electron spin at the Pt center. One-electron oxidation of 3 gave [Pt(tbu-salen)]NO3 (6) as a solid, where the oxidation state of the Pt center was determined to be ca. +2.5 from the XPS and XANES measurements.

show abstract

Section: Resultsmentioning

confidence: 99%

Syntheses and Electronic Structures of One-Electron-Oxidized Group 10 Metal(II)−(Disalicylidene)diamine Complexes (Metal = Ni, Pd, Pt)

et al. 2007

View full text Add to dashboard Cite

show abstract

Tuning of Charge Density Wave Strengths by Competition between Electron−Phonon Interaction of Pd^II−Pd^IV Mixed-Valence States and Electron Correlation of Ni^III States in Quasi-One-Dimensional Bromo-Bridged Ni−Pd Mixed-Metal MX Chain Compounds Ni₁_-_xPd_x(chxn)₂Br₃

et al. 1999

Self Cite

View full text Add to dashboard Cite

A series of single crystals of quasi-one-dimensional bromo-bridged Ni-Pd mixed-metal MX chain compounds Ni(1)(-)(x)()Pd(x)()(chxn)(2)Br(3) (chxn = 1(R),2(R)-diaminocyclohexane) have been obtained by electrochemical oxidation methods of the mixed methanol solutions of parent Ni(II) complex [Ni(chxn)(2)]Br(2) and Pd(II) complex [Pd(chxn)(2)]Br(2) with various mixing ratios. To investigate the competition between the electron correlation of the Ni(III) states (or spin density wave states) and the electron-phonon interaction of the Pd(II)-Pd(IV) mixed-valence states (or charge density wave states) in the Ni-Pd mixed-metal compounds, IR, Raman, ESR, XP, and Auger spectra have been measured. The IR, resonance Raman, XP, and Auger spectra show that the Pd(II)-Pd(IV) mixed-valence states are influenced and gradually approach the Pd(III) states with the increase of the Ni(III) components. This means that in these compounds the electron-phonon interaction in the Pd(II)-Pd(IV) mixed-valence states is weakened with the strong electron correlation in the Ni(III) states.

show abstract

Structure and Physical Properties of Molecule-Based Magnets Including Transition Metal Complexes of Crown Thioethers

Nishijo¹,

Miyazaki²,

Enoki³

2004

Bulletin of the Chemical Society of Japan

View full text Add to dashboard Cite

A new series of molecule-based magnets, including crown thioether (9S3 = 1,4,7-trithiacyclononane) complexes of transition metals (Ni, Co, Cu), are presented. TCNQ salts [M(9S3)2](TCNQ)2 (M = Ni, Co) are one-dimensional (1D), antiferromagnetic (AF) complexes with an intra-chain interaction J = −3.9 K and −1.3 K for M = Ni and Co, respectively, despite its long intermolecular distance, for which the large spin density on the sulfur atom in the magnetic [M(9S3)2]2+ cation is responsible. The mixed valence salt [M(9S3)2](TCNQ)3 (M = Ni, Co) is a paramagnetic semiconductor. 1D AF magnet [Cu(9S3)Br2] does not undergo any magnetic transition because of the weak inter-chain interaction. Substituting a very small amount (∼5%) of Cu with Ni causes a structural change. The change decreases the distances of inter-chain S–S contacts, resulting in the generation of an AF transition at TN = 4.5 K. [M(9S3)2][Ni(bdt)2]2 (M = Ni, Co; bdt = 1,2-benzenedithiolato) are weak-ferromagnets with TN = 6.2 K and 2.6 K for M = Ni and Co, respectively. In the crystals, [M(9S3)2]2+–[Ni(bdt)2]− alternate chains and [Ni(bdt)2]− uniform chains coexist. The appearance of weak-ferromagnetism is associated with a competition between two kinds of inter-chain AF interactions between [M(9S3)2]2+–[Ni(bdt)2]− alternate chains, where the stronger one is an indirect inter-chain interaction through [Ni(bdt)2]− uniform chains, while the weaker is a direct inter-chain interaction.

show abstract

Physical properties of quasi-one-dimensional charge-transfer metal complexes;[M(HBQD)2]TCNQ (M=Ni, Pd; H2BQD=1,2-benzoquinonedioxime)

Cited by 4 publications

References 8 publications

Syntheses and Electronic Structures of One-Electron-Oxidized Group 10 Metal(II)−(Disalicylidene)diamine Complexes (Metal = Ni, Pd, Pt)

Syntheses and Electronic Structures of One-Electron-Oxidized Group 10 Metal(II)−(Disalicylidene)diamine Complexes (Metal = Ni, Pd, Pt)

Tuning of Charge Density Wave Strengths by Competition between Electron−Phonon Interaction of Pd^II−Pd^IV Mixed-Valence States and Electron Correlation of Ni^III States in Quasi-One-Dimensional Bromo-Bridged Ni−Pd Mixed-Metal MX Chain Compounds Ni₁_-_xPd_x(chxn)₂Br₃

Structure and Physical Properties of Molecule-Based Magnets Including Transition Metal Complexes of Crown Thioethers

Contact Info

Product

Resources

About

Physical properties of quasi-one-dimensional charge-transfer metal complexes;[M(HBQD)2]TCNQ (M=Ni, Pd; H2BQD=1,2-benzoquinonedioxime)

Cited by 4 publications

References 8 publications

Syntheses and Electronic Structures of One-Electron-Oxidized Group 10 Metal(II)−(Disalicylidene)diamine Complexes (Metal = Ni, Pd, Pt)

Syntheses and Electronic Structures of One-Electron-Oxidized Group 10 Metal(II)−(Disalicylidene)diamine Complexes (Metal = Ni, Pd, Pt)

Tuning of Charge Density Wave Strengths by Competition between Electron−Phonon Interaction of PdII−PdIV Mixed-Valence States and Electron Correlation of NiIII States in Quasi-One-Dimensional Bromo-Bridged Ni−Pd Mixed-Metal MX Chain Compounds Ni1-xPdx(chxn)2Br3

Structure and Physical Properties of Molecule-Based Magnets Including Transition Metal Complexes of Crown Thioethers

Contact Info

Product

Resources

About

Tuning of Charge Density Wave Strengths by Competition between Electron−Phonon Interaction of Pd^II−Pd^IV Mixed-Valence States and Electron Correlation of Ni^III States in Quasi-One-Dimensional Bromo-Bridged Ni−Pd Mixed-Metal MX Chain Compounds Ni₁_-_xPd_x(chxn)₂Br₃