Intervalence transfer in a new benzotriazolate bridged ruthenium-iron complex

2001 ◽  
Vol 79 (2) ◽  
pp. 145-156
Author(s):  
Reginaldo C Rocha ◽  
Henrique E Toma
Keyword(s):  
Near Infrared ◽  
Mixed Valence ◽  
Differential Pulse ◽  
Iron Complex ◽  
Electronic Coupling ◽  
Near Ir ◽  
Metal Metal ◽  
Dinuclear Ruthenium ◽  
Pulse Voltammetry ◽  
Transfer Properties

The unsymmetrical dinuclear ruthenium–iron complexes [(NH3)5Ru–bta–Fe(CN)5]n (where bta = benzotriazolate; n = –2, –1, 0) were prepared as solid sodium salts from [RuII(NH3)5(bta)]+ or [RuIII(NH3)5(bta)]2+ and [FeII(CN)5(H2O)]3– and characterized in aqueous solution by means of electrochemical and spectroelectrochemical methods. UV-vis, near-infrared, IR, and cyclic and differential pulse voltammetry data suggest that the related mixed valent species belong to a valence trapped formulation, featuring localized Ru(III) and Fe(II) oxidation states. In spite of the class II categorization in the Robin and Day scheme, this system shows a remarkable metal–metal electronic coupling, as deduced from an intense, low-energy, and very broad intervalence band in the near-IR region. In addition, the mixed valence state displays enhanced stabilization in relation to the isovalent state. The intervalence transfer properties are discussed on the basis of Hush's theory.Key words: ammineruthenium complexes, cyanoiron complexes, mixed valence, intervalence, benzotriazole, benzotriazolate.

Orthogonal electronic coupling in multicentre arylamine mixed-valence compounds based on a dibenzofulvene–thiophene conjugated bridge

2017 ◽  
Vol 53 (64) ◽  
pp. 8960-8963 ◽  
Author(s):  
A. Beneduci ◽  
G. A. Corrente ◽  
E. Fabiano ◽  
V. Maltese ◽  
S. Cospito ◽  
...  
Keyword(s):  
Near Infrared ◽  
Mixed Valence ◽  
Infrared Region ◽  
Optical Modulation ◽  
Electronic Coupling ◽  
Voltage Dependent ◽  
Near Infrared Region ◽  
Mixed Valence Compounds

Novel H-shaped tetrarylamine mixed valence compounds showing orthogonal electronic coupling generate voltage-dependent electro-optical modulation in the near infrared region.

Tuning of Metal–Metal Interactions in Mixed-Valence States of Cyclometalated Dinuclear Ruthenium and Osmium Complexes Bearing Tetrapyridylpyrazine or -benzene

2014 ◽  
Vol 33 (18) ◽  
pp. 4893-4904 ◽  
Author(s):  
Takumi Nagashima ◽  
Takuya Nakabayashi ◽  
Takashi Suzuki ◽  
Katsuhiko Kanaizuka ◽  
Hiroaki Ozawa ◽  
...  
Keyword(s):  
Mixed Valence ◽  
Metal Interactions ◽  
Valence States ◽  
Metal Metal ◽  
Dinuclear Ruthenium ◽  
Osmium Complexes

Driving the Localized-to-Delocalized Transition in Unsymmetrical Dinuclear Ruthenium Mixed-Valence Complexes

2005 ◽  
Vol 58 (11) ◽  
pp. 767 ◽  
Author(s):  
Deanna M. D'Alessandro ◽  
F. Richard Keene
Keyword(s):  
Electronic State ◽  
Ground State ◽  
Mixed Valence ◽  
Electronic Coupling ◽  
Classical Analysis ◽  
Bridging Ligand ◽  
Dinuclear Ruthenium ◽  
State Analysis

The degree of delocalization in the symmetrical complexes [{Ru(bpy)2}2(μ-dpb′)]5+ and [{Ru(bpy)2}2(μ-dpb)]5+ (dpb = 2,3-bis(2-pyridyl)-1,4-benzoquinoxaline; dpb′ = dipyrido(2,3-a;3′,2′-c)benzophenazine; bpy = 2,2′-bipyridine) is diminished by the substitution of the terminal bpy ligands at one end of the complex. The results of a classical analysis for the diastereoisomeric forms of the series of complexes [{Ru(bpy)2}(μ-BL){Ru(pp)2}]5+ (pp = bpy, Me2bpy (4,4′-dimethyl-2,2′-bipyridine), Me4bpy (4,4′,5,5′-tetramethyl-2,2′-bipyridine)) indicate that a greater degree of ground-state delocalization exists in the complexes incorporating the bridging ligand dpb′ compared with the dpb analogue. A two-state analysis in which ΔE 0 (the redox asymmetry) is varied at constant H ab (the electronic coupling) and λ (the reorganizational energy) does not adequately describe the properties of the systems due to the importance of a third electronic state corresponding to the bridging ligand.

Mixed valence properties of a pyrazine bridged ruthenium–iron complex

1977 ◽  
Vol 55 (20) ◽  
pp. 3549-3553 ◽  
Author(s):  
Henrique E. Toma ◽  
Paulo S. Santos
Keyword(s):  
Aqueous Solution ◽  
Cyclic Voltammetry ◽  
Binuclear Complex ◽  
Near Infrared ◽  
Mixed Valence ◽  
Infrared Region ◽  
Iron Complex ◽  
Valence Transition ◽  
Near Infrared Region ◽  
Resonance Raman Spectra

A study is presented on the chemistry of the binuclear complex [(CN)5FepzRu(NH3)5]n (n = 0 for the II–III complex and n = −1 for the II–II complex, pz = pyrazine) in solid state and in aqueous solution. Evidence for a mixed valence transition for the II–III complex was observed in the near infrared region. Based on infrared and resonance Raman spectra, a trapped-valence or class II formulation was proposed for the complex. Cyclic voltammetry indicated the occurrence of two reversible waves at 0.48 V and 0.72 V vs. NHE, which were assigned to the oxidation of the ruthenium(II) and iron(II) centers, respectively.

Unprecedented metal–metal bonded {Ru4(μ3-O)2} butterfly core in oxido-carboxylato bridged mixed valence cluster—structural elucidation and electronic forms in accessible redox states

2020 ◽  
Vol 49 (39) ◽  
pp. 13573-13581
Author(s):  
Sudip Kumar Bera ◽  
Goutam Kumar Lahiri
Keyword(s):  
Infrared Absorption ◽  
Near Infrared ◽  
Mixed Valence ◽  
Structural Elucidation ◽  
Redox States ◽  
Metal Metal

A metal–metal bonded butterfly core in mixed valence 1 (RuIII3RuIV, S = 1/2) displayed near-infrared absorption and anisotropic EPR, while oxidised 1+ (RuIII2RuIV2) or reduced 1− (RuIII4) is attributed to the spin-paired S = 0 state.

Mixed-valence properties of a dinuclear ruthenium complex bridged by bis(phenylcyanamido)tetrazine

2014 ◽  
Vol 92 (11) ◽  
pp. 1081-1085 ◽  
Author(s):  
Fatemeh Habibagahi ◽  
Robert J. Crutchley
Keyword(s):  
Ruthenium Complex ◽  
Mixed Valence ◽  
Transition Dipole Moment ◽  
The Novel ◽  
Transition Dipole ◽  
H Nmr ◽  
Bridging Ligand ◽  
Metal Metal ◽  
Dinuclear Ruthenium ◽  
The Stability

The novel bridging ligand 3,6-bis(phenylcyanamido)-1,2,4,5-tetrazine (tdpcH2) and its dinuclear complex [{Ru(ttpy)(bpy)}2(μ-tdpc)][PF6]2 were prepared and characterized by elemental analysis and 1H NMR spectroscopy. Cyclic voltammetry and vis-NIR and IR spectroelectrochemistry of [{Ru(ttpy)(bpy)}2(μ-tdpc)]2+ showed that [{Ru(ttpy)(bpy)}2(μ-tdpc)]3+ is a Class II mixed-valence system with metal−metal coupling of 400 cm−1 assuming a transition dipole moment length of 21 Å. DFT calculations of tdpc2− suggested that the stability of the HOMO results in weak metal−metal coupling via the hole-superexchange mechanism.

Plasmon-assisted interaction of Si with light, for cancer hyperthermia and electromagnetic energy harvest

2020 ◽  
Vol 92 (2) ◽  
pp. 20101
Author(s):  
Behnam Kheyraddini Mousavi ◽  
Morteza Rezaei Talarposhti ◽  
Farshid Karbassian ◽  
Arash Kheyraddini Mousavi
Keyword(s):  
Silicon Nanowires ◽  
Metallic Nanoparticles ◽  
Near Infrared ◽  
Optical Transition ◽  
Electromagnetic Energy ◽  
Energy Harvest ◽  
Absorption Enhancement ◽  
Ir Absorption ◽  
Absorption Mechanism ◽  
Near Ir

Metal-assisted chemical etching (MACE) is applied for fabrication of silicon nanowires (SiNWs). We have shown the effect of amorphous sheath of SiNWs by treating the nanowires with SF6 and the resulting reduction of absorption bandwidth, i.e. making SiNWs semi-transparent in near-infrared (IR). For the first time, by treating the fabricated SiNWs with copper containing HF∕H2O2∕H2O solution, we have generated crystalline nanowires with broader light absorption spectrum, up to λ = 1 μm. Both the absorption and photo-luminescence (PL) of the SiNWs are observed from visible to IR wavelengths. It is found that the SiNWs have PL at visible and near Infrared wavelengths, which may infer presence of mechanisms such as forbidden gap transitions other can involvement of plasmonic resonances. Non-radiative recombination of excitons is one of the reasons behind absorption of SiNWs. Also, on the dielectric metal interface, the absorption mechanism can be due to plasmonic dissipation or plasmon-assisted generation of excitons in the indirect band-gap material. Comparison between nanowires with and without metallic nanoparticles has revealed the effect of nanoparticles on absorption enhancement. The broader near IR absorption, paves the way for applications like hyperthermia of cancer while the optical transition in near IR also facilitates harvesting electromagnetic energy at a broad spectrum from visible to IR.

Investigations On The Binding Of Mercury Ions To Albumins Employing Differential Pulse Voltammetry

2003 ◽  
Vol 10 (2) ◽  
pp. 155-164 ◽  
Author(s):  
Clarissa Pires de Castro ◽  
Jurandir SouzaDe ◽  
Carlos Bloch Jr
Keyword(s):  
Differential Pulse Voltammetry ◽  
Differential Pulse ◽  
Mercury Ions ◽  
Pulse Voltammetry

Solar Exfoliated Graphene Oxide: A Platform for Electrochemical Sensing of Epinephrine

2020 ◽  
Vol 16 (4) ◽  
pp. 393-403 ◽  
Author(s):  
Renjini Sadhana ◽  
Pinky Abraham ◽  
Anithakumary Vidyadharan
Keyword(s):  
Cyclic Voltammetry ◽  
Graphene Oxide ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Simultaneous Detection ◽  
Differential Pulse ◽  
Carbon Electrode ◽  
Modified Glassy Carbon Electrode ◽  
Reduced Graphene ◽  
Pulse Voltammetry

Introduction: In this study, solar exfoliated graphite oxide modified glassy carbon electrode was used for the anodic oxidation of epinephrine in a phosphate buffer medium at pH7. The modified electrode showed fast response and sensitivity towards Epinephrine Molecule (EP). The electrode was characterized electrochemically through Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). Area of the electrode enhanced three times during modification and studies reveal that the oxidation process of EP occurs by an adsorption controlled process involving two electrons. The results showed a detection limit of 0.50 ± 0.01μM with a linear range up to 100 μM. The rate constant calculated for the electron transfer reaction is 1.35 s-1. The electrode was effective for simultaneous detection of EP in the presence of Ascorbic Acid (AA) and Uric Acid (UA) with well-resolved signals. The sensitivity, selectivity and stability of the sensor were also confirmed. Methods: Glassy carbon electrode modified by reduced graphene oxide was used for the detection and quantification of epinephrine using cyclic voltammetry and differential pulse voltammetry. Results: The results showed an enhancement in the electrocatalytic oxidation of epinephrine due to the increase in the effective surface area of the modified electrode. The anodic transfer coefficient, detection limit and electron transfer rate constant of the reaction were also calculated. Conclusion: The paper reports the determination of epinephrine using reduced graphene oxide modified glassy carbon electrode through CV and DPV. The sensor exhibited excellent reproducibility and repeatability for the detection of epinephrine and also its simultaneous detection of ascorbic acid and uric acid, which coexist in the biological system.

Sign in / Sign up

Export Citation Format

Share Document