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1.
《Electroanalysis》2005,17(3):210-222
Presented in this work is the first step towards an enzymeless/mediatorless glucose sensor. We first observed remarkable electrocatalytic oxidation of glucose using combinative ruthenium oxide (RuOx)‐Prussian blue (PB) analogues (designated as mvRuOx‐RuCN, mv: mixed valent) at ca. 1.1 V (vs. Ag/AgCl) in acidic media (pH 2 Na2SO4/H2SO4). Individual RuOx and PB analogs failed to give any such catalytic response. A high ruthenium oxidation state (i.e., oxy/hydroxy‐RuVII, E°≈1.4 V vs. RHE), normally occurring in strong alkaline conditions at RuOx‐based electrodes, was electrogenerated and stabilized (without any conventional disproportionation reaction) in the mvRuOx‐RuCN matrix for glucose catalysis. Detail X‐ray photoelectron spectroscopic studies can fully support the observation. The catalyst was chemically modified onto a disposable screen‐printed carbon electrode and employed for the amperometric detection of glucose via flow injection analysis (FIA). This system has a linear detection range of 0.3–20 mM with a detection limit and sensitivity of 40 μM (S/N=3) and 6.2 μA/(mM cm2), respectively, for glucose. Further steps towards the elimination of interference and the extendibility to neutral pHs were addressed. 相似文献
2.
Ruthenium Hexacyanoferrate (III) Modified Glassy Carbon Electrode for Determination of Captopril
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I. A. R. B. Dias W. M. Costa P. Cervini E. T. G. Cavalheiro A. L. B. Marques 《Electroanalysis》2016,28(9):2136-2142
A glassy carbon electrode modified with a ruthenium (III) hexacyanoferrate film was investigated for the determination of captopril in pharmaceutical formulations. The RuOHCF film was deposited on the surface of the electrode after applying 50 successive cycles and subsequent stabilization in a mixture of NaNO3 0.50 mol L?1+HCl 0.050 mol L?1 used as supporting electrolyte. The main processes responsible for the redox electrode response are attributed to the system RuII/RuIII/RuIV, and appeared at ?0.080, 0.86 and 1.01 V (vs. SCE). The redox process at ?0.080 V was selected for the determination of captopril in the present study, once it provided higher sensibility and occurs in a lower potential than the other ones which can prevent interferences. The experimental parameters used in the determination of the analyte, using differential pulse voltammetry were optimized: pulse amplitude: 50 mV, scan rate: 5 mV s?1 and potential window: ?0.5 to 0.2 V (vs. SCE). The analytical application of the sensor in real samples demonstrated a linear range between 0.060 and 0.80 µmol L?1 (r=0.998) with a detection limit of 0.047 µmol L?1. A mechanism based on co‐precipitation of captopril and the Ru (III) complex in the film is presented once the signal of the RuII/III redox couple decreases with increasing the analyte concentration. Recoveries of 99 to 100 % were achieved in pharmaceutical samples and the proposed procedure agreed with the HPLC official method within 95 % confidence level, according to the t‐Student test. 相似文献
3.
Dr. Masaki Yoshida Dr. Mio Kondo Prof. Toshikazu Nakamura Prof. Ken Sakai Prof. Shigeyuki Masaoka 《Angewandte Chemie (International ed. in English)》2014,53(43):11519-11523
A series of [{(terpy)(bpy)Ru}(μ‐O){Ru(bpy)(terpy)}]n+ ( [RuORu]n+ , terpy=2,2′;6′,2′′‐terpyridine, bpy=2,2′‐bipyridine) was systematically synthesized and characterized in three distinct redox states (n=3, 4, and 5 for RuII,III2 , RuIII,III2 , and RuIII,IV2 , respectively). The crystal structures of [RuORu]n+ (n=3, 4, 5) in all three redox states were successfully determined. X‐ray crystallography showed that the Ru? O distances and the Ru‐O‐Ru angles are mainly regulated by the oxidation states of the ruthenium centers. X‐ray crystallography and ESR spectra clearly revealed the detailed electronic structures of two mixed‐valence complexes, [RuIIIORuIV]5+ and [RuIIORuIII]3+ , in which each unpaired electron is completely delocalized across the oxo‐bridged dinuclear core. These findings allow us to understand the systematic changes in structure and electronic state that accompany the changes in the redox state. 相似文献
4.
Yoshihiro Shimoyama Dr. Tomoya Ishizuka Dr. Hiroaki Kotani Prof. Dr. Yoshihito Shiota Prof. Dr. Kazunari Yoshizawa Dr. Kaoru Mieda Prof. Dr. Takashi Ogura Dr. Toshihiro Okajima Prof. Dr. Shunsuke Nozawa Prof. Dr. Takahiko Kojima 《Angewandte Chemie (International ed. in English)》2016,55(45):14041-14045
Proton‐coupled electron‐transfer oxidation of a RuII?OH2 complex, having an N‐heterocyclic carbene ligand, gives a RuIII?O. species, which has an electronically equivalent structure of the RuIV=O species, in an acidic aqueous solution. The RuIII?O. complex was characterized by spectroscopic methods and DFT calculations. The oxidation state of the Ru center was shown to be close to +3; the Ru?O bond showed a lower‐energy Raman scattering at 732 cm?1 and the Ru?O bond length was estimated to be 1.77(1) Å. The RuIII?O. complex exhibits high reactivity in substrate oxidation under catalytic conditions; particularly, benzaldehyde and the derivatives are oxidized to the corresponding benzoic acid through C?H abstraction from the formyl group by the RuIII?O. complex bearing a strong radical character as the active species. 相似文献
5.
Controlling the Direction of the Molecular Axis of Rod‐Shaped Binuclear Ruthenium Complexes on Single‐Walled Carbon Nanotubes
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Dr. Hiroaki Ozawa Kazuma Kosaka Tomomi Kita Kai Yoshikawa Prof. Dr. Masa‐aki Haga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(19):6575-6582
We report the synthesis of a mixed‐valence ruthenium complex, bearing pyrene moieties on one side of the ligands as anchor groups. Composites consisting of mixed‐valence ruthenium complexes and SWNTs were prepared by noncovalent π–π interactions between the SWNT surface and the pyrene anchors of the Ru complex. In these composites, the long axis of the Ru complexes was aligned in parallel to the principal direction of the SWNT. The optimized conformation of these complexes on the SWNT surface was calculated by molecular mechanics. The composites were examined by UV/Vis absorption and FT‐IR spectroscopy, XPS, and SEM analysis. Furthermore, their electrochemical properties were evaluated. Cyclic voltammograms of the composites showed reversible oxidation waves at peak oxidation potentials (Epox) = 0.86 and 1.08 V versus Fc+/Fc, which were assigned to the RuII‐RuII/RuII‐RuIII and the RuII‐RuIII/RuIII‐RuIII oxidation events of the dinuclear ruthenium complex, respectively. Based on these observations, we concluded that the electrochemical properties and mixed‐valence state of the dinuclear ruthenium complexes were preserved upon attachment to the SWNT surface. 相似文献
6.
Redox‐Active‐Ligand‐Mediated Formation of an Acyclic Trinuclear Ruthenium Complex with Bridging Nitrido Ligands
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Dr. Bidraha Bagh Daniël L. J. Broere Dr. Maxime A. Siegler Dr. Ir. Jarl Ivar van der Vlugt 《Angewandte Chemie (International ed. in English)》2016,55(29):8381-8385
Coordination of a redox‐active pyridine aminophenol ligand to RuII followed by aerobic oxidation generates two diamagnetic RuIII species [ 1 a (cis) and 1 b (trans)] with ligand‐centered radicals. The reaction of 1 a / 1 b with excess NaN3 under inert atmosphere resulted in the formation of a rare bis(nitrido)‐bridged trinuclear ruthenium complex with two nonlinear asymmetrical Ru‐N‐Ru fragments. The spontaneous reduction of the ligand centered radical in the parent 1 a / 1 b supports the oxidation of a nitride (N3?) to half an equivalent of N2. The trinuclear omplex is reactive toward TEMPO‐H, tin hydrides, thiols, and dihydrogen. 相似文献
7.
Density Functional Theory Calculations on Oxidative CC Bond Cleavage and NO Bond Formation of [RuII(bpy)2(diamine)]2+ via Reactive Ruthenium Imide Intermediates
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Dr. Xiangguo Guan Siu‐Man Law Chun‐Wai Tse Dr. Jie‐Sheng Huang Prof. Dr. Chi‐Ming Che 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):15122-15130
DFT calculations are performed on [RuII(bpy)2(tmen)]2+ ( M1 , tmen=2,3‐dimethyl‐2,3‐butanediamine) and [RuII(bpy)2(heda)]2+ ( M2 , heda=2,5‐dimethyl‐2,5‐hexanediamine), and on the oxidation reactions of M1 to give the C?C bond cleavage product [RuII(bpy)2(NH=CMe2)2]2+ ( M3 ) and the N?O bond formation product [RuII(bpy)2(ONCMe2CMe2NO)]2+ ( M4 ). The calculated geometrical parameters and oxidation potentials are in good agreement with the experimental data. As revealed by the DFT calculations, [RuII(bpy)2(tmen)]2+ ( M1 ) can undergo oxidative deprotonation to generate Ru‐bis(imide) [Ru(bpy)2(tmen‐4 H)]+ ( A ) or Ru‐imide/amide [Ru(bpy)2(tmen‐3 H)]2+ ( A′ ) intermediates. Both A and A′ are prone to C?C bond cleavage, with low reaction barriers (ΔG≠) of 6.8 and 2.9 kcal mol?1 for their doublet spin states 2 A and 2 A′ , respectively. The calculated reaction barrier for the nucleophilic attack of water molecules on 2 A′ is relatively high (14.2 kcal mol?1). These calculation results are in agreement with the formation of the RuII‐bis(imine) complex M3 from the electrochemical oxidation of M1 in aqueous solution. The oxidation of M1 with CeIV in aqueous solution to afford the RuII‐dinitrosoalkane complex M4 is proposed to proceed by attack of the cerium oxidant on the ruthenium imide intermediate. The findings of ESI‐MS experiments are consistent with the generation of a ruthenium imide intermediate in the course of the oxidation. 相似文献
8.
Ketimido Metallophthalocyanines: An Approach to Phthalocyanine‐Supported Mononuclear High‐Valent Ruthenium Complexes
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Dr. Jie‐Sheng Huang Dr. Kwok‐Ming Wong Dr. Sharon Lai‐Fung Chan Ken Chi‐Hang Tso Tao Jiang Prof. Dr. Chi‐Ming Che 《化学:亚洲杂志》2014,9(1):338-350
A “metal–ketimine+ArI(OR)2” approach has been developed for preparing metal–ketimido complexes, and ketimido ligands are found to stabilize high‐valent metallophthalocyanine (M? Pc) complexes such as ruthenium(IV) phthalocyanines. Treatment of bis(ketimine) ruthenium(II) phthalocyanines [RuII(Pc)(HN?CPh2)2] ( 1a ) and [RuII(Pc)(HNQu)2] ( 1b ; HNQu=N‐phenyl‐1,4‐benzoquinonediimine) with PhI(OAc)2 affords bis(ketimido) ruthenium(IV) phthalocyanines [RuIV(Pc)(N?CPh2)2] ( 2a ) and [RuIV(Pc)(NQu)2] ( 2b ), respectively. X‐ray crystal structures of 1b and [RuII(Pc)(PhN?CHPh)2] ( 1c ) show Ru? N(ketimine) distances of 2.075(4) and 2.115(3) Å, respectively. Complexes 2a , 2b readily revert to 1a , 1b upon treatment with phenols. 1H NMR spectroscopy reveals that 2a , 2b are diamagnetic and 2b exists as two isomers, consistent with a proposed eclipsed orientation of the ketimido ligands in these ruthenium(IV) complexes. The reaction of 1a , 1b with PhI(OAc)2 to afford 2a , 2b suggests the utility of ArI(OR)2 as an oxidative deprotonation agent for the generation of high‐valent metal complexes featuring M? N bonds with multiple bonding characters. DFT and time‐dependent (TD)‐DFT calculations have been performed on the electronic structures and the UV/Vis absorption spectra of 1b and 2b , which provide support for the diamagnetic nature of 2b and reveal a significant barrier for rotation of the ketimido group about the Ru? N(ketimido) bond. 相似文献
9.
Evaluation of the Oxo‐bridged Dinuclear Ruthenium Ammine Complex as Redox Mediator in an Electrochemical Biosensor
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Paulo A. Raymundo‐Pereira Ana C. V. Mascarenhas Marcos F. S. Teixeira 《Electroanalysis》2016,28(3):562-569
The mediation of electron‐transfer by oxo‐bridged dinuclear ruthenium ammine [(bpy)2(NH3)RuIII(µ‐O)RuIII(NH3)(bpy)2]4+ for the oxidation of glucose was investigated by cyclic voltammetry. These ruthenium (III) complexes exhibit appropriate redox potentials of 0.131–0.09 V vs. SCE to act as electron‐transfer mediators. The plot of anodic current vs. the glucose concentration was linear in the concentration range between 2.52×10?5 and 1.00×10?4 mol L?1. Moreover, the apparent Michaelis‐Menten kinetic (KMapp) and the catalytic (Kcat) constants were 8.757×10?6 mol L?1 and 1,956 s?1, respectively, demonstrating the efficiency of the ruthenium dinuclear oxo‐complex [(bpy)2(NH3)RuIII(µ‐O)RuIII(NH3)(bpy)2]4+ as mediator of redox electron‐transfer. 相似文献
10.
A series of octahedral RuII/RuIII complexes of the type [Ru(Y)(CO)(BAX)(PPh3)2] and [RuCl2(BAX)(PPh3)2] (Y = H or Cl; BAX = benzaldehydeacetylhydrazone anion; X = H, Me, OMe, OH, Cl or NO2) have been prepared and characterised by spectral, magnetic and cyclic voltammetric studies. The RuII complexes are low spin diamagnetic (S = 0) whereas the RuIII complexes are low spin and paramagnetic (S = 1/2). These RuII and RuIII complexes absorb in the visible region respectively at ca. 16,000 and 28,000 cm–1 which bands are assigned to the MLCT. The correlation of the max values of the RuIII complexes with the + Hammett parameter, is linear, indicating the profound effect of substituents on the electron density of the central metal. I.r. spectral data reveals that the hydrazone is chelated to ruthenium through the hydrazinic nitrogen and the deprotonated enolic oxygen. The rhombic nature of the e.s.r. spectra of the RuIII complexes indicates an asymmetry in the electronic environment around the Ru atom. RuII complexes in CH2Cl2 show an irreversible RuII/III redox couple at ca. 0.9–0.5 V, while the RuIII complexes show two reversible redox couples in the –0.1–0.1 and 0.8–0.6 V range, indicating that the higher oxidation state of ruthenium is stabilised by hydrazones. 相似文献
11.
The complex cis‐[RuIII(dmbpy)2Cl2](PF6) ( 2 ) (dmbpy = 4, 4′‐dimethyl‐2, 2′‐bipyridine) was obtained from the reaction of cis‐[RuII(dmbpy)2Cl2] ( 1 ) with ammonium cerium(IV) nitrate followed by precipitation with saturated ammonium hexafluoridophosphate. The 1H NMR spectrum of the RuIII complex confirms the presence of paramagnetic metal atoms, whereas that of the RuII complex displays diamagnetism. The 31P NMR spectrum of the RuIII complex shows one signal for the phosphorus atom of the PF6– ion. The perspective view of each [RuII/III(dmbpy)2Cl2]0/+ unit manifests that the ruthenium atom is in hexacoordinate arrangement with two dmbpy ligands and two chlorido ligands in cis position. As the oxidation state of the central ruthenium metal atom becomes higher, the average Ru–Cl bond length decreases whereas the Ru–N (dmbpy) bond length increases. The cis‐positioned dichloro angle in RuIII is 1.3° wider than that in the RuII. The dihedral angles between pair of planar six‐membered pyridyl ring in the dmbpy ligand for the RuII are 4.7(5)° and 5.7(4)°. The observed inter‐planar angle between two dmbpy ligands in the RuII is 89.08(15)°, whereas the value for the RuIII is 85.46(20)°. 相似文献
12.
Michael Nussbaum Dr. Oliver Schuster Prof. Dr. Martin Albrecht 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(51):17517-17527
A ditopic benzobis(carbene) ligand precursor was prepared that contained a chelating pyridyl moiety to ensure co‐planarity of the carbene ligand and the coordination plane of a bound octahedral metal center. Bimetallic ruthenium complexes comprising this ditopic ligand [L4Ru‐C,N‐bbi‐C,N‐RuL4] were obtained by a transmetalation methodology (C,N‐bbi‐C,N=benzobis(N‐pyridyl‐N′‐methyl‐imidazolylidene). The two metal centers are electronically decoupled when the ruthenium is in a pseudotetrahedral geometry imparted by a cymene spectator ligand (L4=[(cym)Cl]). Ligand exchange of the Cl?/cymene ligands for two bipyridine or four MeCN ligands induced a change of the coordination geometry to octahedral. As a consequence, the ruthenium centers, separated through space by more than 10 Å, become electronically coupled, which is evidenced by two distinctly different metal‐centered oxidation processes that are separated by 134 mV (L4=[(bpy)2]; bpy=2,2′‐bipyridine) and 244 mV (L4=[(MeCN)4]), respectively. Hush analysis of the intervalence charge‐transfer bands in the mixed‐valent species indicates substantial valence delocalization in both complexes (delocalization parameter Γ=0.41 and 0.37 in the bpy and MeCN complexes, respectively). Spectroelectrochemical measurements further indicated that the mixed‐valent RuII/RuIII species and the fully oxidized RuIII/RuIII complexes gradually decompose when bound to MeCN ligands, whereas the bpy spectators significantly enhance the stability. These results demonstrate the efficiency of carbenes and, in particular, of the bbi ligand scaffold for mediating electron transfer and for the fabrication of molecular redox switches. Moreover, the relevance of spectator ligands is emphasized for tailoring the degree of electronic communication through the benzobis(carbene) linker. 相似文献
13.
Electrochemical Detection of Persulfate at the Modified Glassy Carbon Electrode with Nanocomposite Containing Nano‐Ruthenium Oxide/Thionine and Nano‐Ruthenium Oxide/Celestine Blue
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The present study describes the fabrication of a sensitive amperometric sensor for the determination of persulfate. The immobilization surface was prepared by modifying a glassy carbon (GC) electrode with a nanocomposite containing ruthenium oxide (RuOx) nanoparticles and thionine (TH) or celestin blue (CB). The modified electrodes indicated excellent electrocatalytic activity toward persulfate reduction at a potential of +0.1 V. The proposed sensor showed detection limits of 1.46 µM for the GC/RuOx/TH modified electrode and 2.64 µM for the GC/RuOx/CB modified electrode. The sensitivities were obtained as 3 nA µM?1 at a concentration range of 10 µM to 11 mM for the GC/RuOx/TH modified electrode and 1 nA µM?1 at a concentration range of 10 µM to 6 mM for the GC/RuOx/CB modified electrodes. 相似文献
14.
This article deals with the hitherto unexplored metal complexes of deprotonated 6,12‐di(pyridin‐2‐yl)‐5,11‐dihydroindolo[3,2‐b]carbazole (H2L). The synthesis and structural, optical, electrochemical characterization of dimeric [{RuIII(acac)2}2(μ‐L.?)]ClO4 ([ 1 ]ClO4, S=1/2), [{RuII(bpy)2}2(μ‐L.?)](ClO4)3 ([ 2 ](ClO4)3, S=1/2), [{RuII(pap)2}2(μ‐L2?)](ClO4)2 ([ 4 ](ClO4)2, S=0), and monomeric [(bpy)2RuII(HL?)]ClO4 ([ 3 ]ClO4, S=0), [(pap)2RuII(HL?)]ClO4 ([ 5 ]ClO4, S=0) (acac=σ‐donating acetylacetonate, bpy=moderately π‐accepting 2,2’‐bipyridine, pap=strongly π‐accepting 2‐phenylazopyridine) are reported. The radical and dianionic states of deprotonated L in isolated dimeric 1 +/ 2 3+ and 4 2+, respectively, could be attributed to the varying electronic features of the ancillary (acac, bpy, and pap) ligands, as was reflected in their redox potentials. Perturbation of the energy level of the deprotonated L or HL upon coordination with {Ru(acac)2}, {Ru(bpy)2}, or {Ru(pap)2} led to the smaller energy gap in the frontier molecular orbitals (FMO), resulting in bathochromically shifted NIR absorption bands (800–2000 nm) in the accessible redox states of the complexes, which varied to some extent as a function of the ancillary ligands. Spectroelectrochemical (UV/Vis/NIR, EPR) studies along with DFT/TD‐DFT calculations revealed (i) involvement of deprotonated L or HL in the oxidation processes owing to its redox non‐innocent potential and (ii) metal (RuIII/RuII) or bpy/pap dominated reduction processes in 1 + or 2 2+/ 3 +/ 4 2+/ 5 +, respectively. 相似文献
15.
Exploring Bis(cyclometalated) Ruthenium(II) Complexes as Active Catalyst Precursors: Room‐Temperature Alkene–Alkyne Coupling for 1,3‐Diene Synthesis
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Jing Zhang Dr. Angel Ugrinov Prof. Dr. Yong Zhang Prof. Dr. Pinjing Zhao 《Angewandte Chemie (International ed. in English)》2014,53(32):8437-8440
Described is the development of a new class of bis(cyclometalated) ruthenium(II) catalyst precursors for C? C coupling reactions between alkene and alkyne substrates. The complex [(cod)Ru(3‐methallyl)2] reacts with benzophenone imine or benzophenone in a 1:2 ratio to form bis(cyclometalated) ruthenium(II) complexes ( 1 ). The imine‐ligated complex 1 a promoted room‐temperature coupling between acrylic esters and amides with internal alkynes to form 1,3‐diene products. A proposed catalytic cycle involves C? C bond formation by oxidative cyclization, β‐hydride elimination, and C? H bond reductive elimination. This RuII/RuIV pathway is consistent with the observed catalytic reactivity of 1 a for mild tail‐to‐tail methyl acrylate dimerization and for cyclobutene formation by [2+2] norbornene/alkyne cycloaddition. 相似文献
16.
Dr. Eszter M. Nagy Andrea Pettenuzzo Giulia Boscutti Prof. Dr. Luciano Marchiò Prof. Dr. Lisa Dalla Via Prof. Dr. Dolores Fregona 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(45):14464-14472
Hereby we present the synthesis of several ruthenium(II) and ruthenium(III) dithiocarbamato complexes. Proceeding from the Na[trans‐RuIII(dmso)2Cl4] ( 2 ) and cis‐[RuII(dmso)4Cl2] ( 3 ) precursors, the diamagnetic, mixed‐ligand [RuIIL2(dmso)2] complexes 4 and 5 , the paramagnetic, neutral [RuIIIL3] monomers 6 and 7 , the antiferromagnetically coupled ionic α‐[RuIII2L5]Cl complexes 8 and 9 as well as the β‐[RuIII2L5]Cl dinuclear species 10 and 11 (L=dimethyl‐ (DMDT) and pyrrolidinedithiocarbamate (PDT)) were obtained. All the compounds were fully characterised by elemental analysis as well as 1H NMR and FTIR spectroscopy. Moreover, for the first time the crystal structures of the dinuclear β‐[RuIII2(dmdt)5]BF4 ? CHCl3 ? CH3CN and of the novel [RuIIL2(dmso)2] complexes were also determined and discussed. For both the mono‐ and dinuclear RuII and RuIII complexes the central metal atoms assume a distorted octahedral geometry. Furthermore, in vitro cytotoxicity of the complexes has been evaluated on non‐small‐cell lung cancer (NSCLC) NCI‐H1975 cells. All the mono‐ and dinuclear RuIII dithiocarbamato compounds (i.e., complexes 6 – 10 ) show interesting cytotoxic activity, up to one order of magnitude higher with respect to cisplatin. Otherwise, no significant antiproliferative effect for either the precursors 2 and 3 or the RuII complexes 4 and 5 has been observed. 相似文献
17.
Ruthenium(III) Phthalocyanines: Synthesis and Properties of Di(halo)phthalocyaninato(1?)ruthenium(III) Di(halo)phthalocyaninato(1?)ruthenium(III), [Ru(X)2Pc?] (X = Cl, Br, I) is prepared by oxidation of [Ru(X)2Pc2?]? (Cl, Br, OH) with halogene in dichloromethane. The magnetic moment of [Ru(X)2Pc?] is 2,48 μB (X = Cl) resp. 2,56 μB (X = Br) in accordance with a systeme of two independent spins (low spin RuIII and Pc?: S = 1/2). The optical spectra of the red violet solution of [Ru(X)2Pc?] (Cl, Br) are typical for the Pc? ligand with the “B” at 13.5 kK, “Q1” at 19.3 kK and “Q2 region” at 31.9 kK. Sytematic spectral changes within the iron group are discussed. The presence of the Pc? ligand is confirmed by the vibrational spectra, too. Characteristic are the metal dependent bands in the m.i.r. spectra at 1 352 and 1 458 cm?1 and the strong Raman line at 1 600 cm?1. The antisymmetric Ru? X stretch (vas(Ru? X)) is observed at 189 cm?1 (X = I) resp. 234 cm?1 (X = Br). There are two interdependent bands at 295 and 327 cm?1 in the region expected for vas(Ru? Cl) attributed to strong interaction of vas(Ru? Cl) with an out-of-plane Pc? tilting mode of the same irreducible representation. Only the symmetric Ru? Br stretch at 183 cm?1 is selectively enhanced in the resonance-Raman(RR) spectra. The Raman line at 168 cm?1 of the diiodo complex is assigned to loosely bound iodine. The broad band at 978 cm?1 in the RR spectra of the dichloro complex is due to an intraconfigurational transition within the electronic ground state of low spin RuIII split by spin orbit coupling. 相似文献
18.
Wanhua Wu Shaomin Ji Wenting Wu Jingyin Shao Dr. Huimin Guo Prof. Tony D. James Prof. Jianzhang Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(16):4953-4964
RuII–bis‐pyridine complexes typically absorb below 450 nm in the UV spectrum and their molar extinction coefficients are only moderate (ε<16 000 M ?1 cm?1). Thus, RuII–polyimine complexes that show intense visible‐light absorptions are of great interest. However, no effective light‐harvesting ruthenium(II)/organic chromophore arrays have been reported. Herein, we report the first visible‐light‐harvesting RuII–coumarin arrays, which absorb at 475 nm (ε up to 63 300 M ?1 cm?1, 4‐fold higher than typical RuII–polyimine complexes). The donor excited state in these arrays is efficiently converted into an acceptor excited state (i.e., efficient energy‐transfer) without losses in the phosphorescence quantum yield of the acceptor. Based on steady‐state and time‐resolved spectroscopy and DFT calculations, we proposed a general rule for the design of RuII–polypyridine–chromophore light‐harvesting arrays, which states that the 1IL energy level of the ligand must be close to the respective energy level of the metal‐to‐ligand charge‐transfer (M LCT) states. Lower energy levels of 1IL/3IL than the corresponding 1M LCT/3M LCT states frustrate the cascade energy‐transfer process and, as a result, the harvested light energy cannot be efficiently transferred to the acceptor. We have also demonstrated that the light‐harvesting effect can be used to improve the upconversion quantum yield to 15.2 % (with 9,10‐diphenylanthracene as a triplet‐acceptor/annihilator), compared to the parent complex without the coumarin subunit, which showed an upconversion quantum yield of only 0.95 %. 相似文献
19.
Electrochemically active ruthenium oxide (RuOx?nH2O), ruthenium oxide/hexachloroiridate (RuOx?nH2O/IrCl62?), and ruthenium oxide/hexachloroiridate/platinum (RuOx?nH2O/IrCl62?/Pt) hybrid films have been prepared from the mixture of Ru3+, IrCl62?, and PtCl62? ions in an acidic aqueous solution. The repetitive cyclic voltammetry (CV) has been used for the film preparation process. The electrochemical properties and the growth mechanism of the above mentioned different kinds of hybrid films have been investigated using CV and electrochemical quartz crystal microbalance. The morphological and quantitative analyses have been carried out using scanning electron microscopy, atomic force microscopy and energy dispersive X‐ray. Among these above mentioned films, RuOx?nH2O/IrCl62?/Pt hybrid film exhibits promising electrocatalytic activity towards the oxidation of arsenic oxide, methanol and reduction of oxygen. Further, detailed study of electrocatalysis using rotating ring disk electrodes and amperometric methods have been carried out for arsenic oxide oxidation and oxygen reduction reactions at the hybrid films. From the results, the sensitivity of RuOx?nH2O/IrCl62?/Pt hybrid film has been calculated for arsenic oxide as 0.7 mA mM?1; and for oxygen as 1.8 mA mM?1. 相似文献
20.
Ruthenium(II)-Phthalocyaninates(1–): Synthesis and Properties of (Halo)(carbonyl)phthalocyaninato(1–)ruthenium(II) Brown-violet (halo)(carbonyl)phthalocyaninato(1–)ruthenium(II), [Ru(X)(CO)Pc?] (X = Cl, Br) is prepared by oxidation of [Ru(X)(CO)Pc2?]? with the corresponding halogen or dibenzoylperoxide. The eff. magnetic moment μeff = 1.74 (X = Cl), 1.68 μB (Br) confirms the presence of a low-spin RuII complex of the Pc? radical. Accordingly, only the first ring oxidation at ~0.64 V and the first ring reduction at ~ ?1.19 V is observed in the cyclovoltammogram of [Ru(X)(CO)Pc2?]?. The UV-VIS-NIR spectra characterizing a monomeric Pc? radical with intense π-π* transitions at 14500, 19800, 25100 and 33900 cm?1 are compared with those of [Ru(Cl)2Pc?] and of monomeric as well as dimeric [Zn(Cl)Pc?]. The IR and resonance Raman(RR) spectra are characteristic for a Pc? radical, too. Diagnostic in-plane vibrations of the Pc? ligand are in the IR spectrum at 1071, 1359, 1445 cm?1 and in the RR spectrum (λ0 = 488.0 nm) at 567, 1597 cm?1. v(C? O) at 1950 cm?1 and v(Ru? X) at 260 (X = Cl) resp. 184 cm?1 (X = Br) are observed only in the IR spectrum. 相似文献