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1.
Summary: Electrochemical reactions of Ruthenium purple, Feequation/tex2gif-stack-1.gif[Ru II(CN) 6] 3 (RP; Fe III-Ru II) were studied using a spectrocyclic voltammetry (SCV) technique. The SCV measurement for an RP film coated on an ITO electrode showed a reversible redox between RP and Ruthenium white (RW; Fe II-Ru II) at 0.14 V vs saturated calomel reference electrode (SCE). An RP film was electrodeposited on a hybrid film of tungsten trioxide (WO 3)/tris(2,2′-bipyridine)ruthenium(II) ([Ru(bpy) 3] 2+; bpy = 2,2′-bipyridine)/poly(sodium 4-styrenesulfonate) (PSS) (denoted as WRP film) from a colloidal solution containing 0.5 mM FeCl 3, 0.5 mM K 4[Ru(CN) 6] and 40 mM KCl using a potentiodynamic multi-sweep technique. In a cyclic voltammogram (CV) of a WRP/RP film, a redox response was observed at 0.61 V in addition to essential redox responses of WRP hybrid film (a [Ru(bpy) 3] 2+/[Ru(bpy) 3] 3+ redox at 1.03 V and a H xWO 3/WO 3 redox below 0.09 V), but a redox response of RW/RP was not observed at 0.14 V. The SCV measurement for the WRP/RP film suggested that the redox response at 0.61 V is attributed to a redox of [Ru(bpy) 3] 2+/[Ru(bpy) 3] 3+ interacted electrostatically with RP. It also showed that RW is oxidized to RP via [Ru(bpy) 3] 2+/[Ru(bpy) 3] 3+ redox and RP is reversibly reduced to RW via H xWO 3/WO 3 redox. This unique geared electrochemical reaction for the WRP/RP film leads to a hysteresis property of an RW/RP redox. 相似文献
2.
AbstractIn the mixed-valence complex [Ru III(NH 3) 5(μ-dpypn)Fe II(CN) 5] with the flexible bridging ligand 1,3-di(4-pyridyl)propane (dpypn), electrostatic interactions between the {Ru(NH 3) 5} 3+ and {Fe(CN) 5} 3? moieties drive a strong bending of dpypn and approximation of the Ru III and Fe II centers, from which the enhanced electronic coupling between metal ions produces an intense intervalence-transfer absorption in the near-infrared region. Density functional theory calculations corroborate both the electrostatic bending in this heterobinuclear complex and a linear geometry in the homobinuclear counterparts [Ru(NH 3) 5(μ-dpypn)Ru(NH 3) 5] 5+ and [Fe(CN) 5(μ-dpypn)Fe(CN) 5] 5?, for which no evidence of electronic coupling was found because of the separation between metal centers. Furthermore, the heterobinuclear species formed an inclusion complex with β-cyclodextrin where the imposed linear geometry prevents significant electronic coupling and intervalence charge transfer between the Ru III and Fe II centers. 相似文献
3.
The heterometallic complexes trans ‐[Cp(dppe)FeNCRu( o ‐bpy)CNFe(dppe)Cp][PF 6] n ( 1 [PF 6] n , n =2, 3, 4; o ‐bpy=1,2‐bis(2,2′‐bipyridyl‐6‐yl)ethane, dppe=1,2‐bis(diphenylphosphino)ethane, Cp=1,3‐cyclopentadiene) in three distinct states have been synthesized and fully characterized. 1 3+[PF 6] 3 and 1 4+[PF 6] 4 are the one‐ and two‐electron oxidation products of 1 2+[PF 6] 2, respectively. The investigated results suggest that 1 [PF 6] 3 is a Class II mixed valence compound. 1 [PF 6] 4 after a thermal treatment at 400 K shows an unusually delocalized mixed valence state of [Fe III‐NC‐Ru III‐CN‐Fe II], which is induced by electron transfer from the central Ru II to the terminal Fe III in 1 [PF 6] 4, which was confirmed by IR spectroscopy, magnetic data, and EPR and Mössbauer spectroscopy. 相似文献
4.
Reaction of either K 3[Fe(CN) 6] or K 4[Fe(CN) 6] with a macrocyclic Cu II complex, [Cu(teta)](ClO 4) 2 (teta = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacylotetradecane), in aqueous solution gave the same product as shown by spectroscopic and physicochemical characterisation. The crystal structure of the complex shows that it is a one-dimensional linear chain type heterobinuclear Fe III–Cu II polymer. The unit is composed of a [Cu(teta)(H 2O) 2] 2+ cationic complex, a Fe III–Cu II alternate linear chain unit, a ClO
4
–
ion and four water molecules. The Cu atom is coordinated in a distorted octahedral arrangement by four nitrogen atoms from one teta ligand and two nitrogen atoms of the bridging cyanide groups. The Cu—N bond distances involving the cyanide bridges, 2.522(7) and 2.608(7)Å, respectively, indicate weak antiferromagnetic interactions between the Fe III and Cu II atoms. 相似文献
5.
It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal-to-metal charge transfer (MMCT) and spin-crossover (SCO) to tune the valence and spin states of metal ions. Herein, a metallocyanate building block is used to link with a Fe II-triazole moiety and generates a mixed-valence complex {[(Tp 4-Me)Fe III(CN) 3] 9[Fe II4(trz-ph) 6]}⋅[Ph 3PMe] 2⋅[(Tp 4-Me)Fe III(CN) 3] ( 1 ; trz-ph=4-phenyl-4 H-1,2,4-triazole). Moreover, MMCT occurs between Fe III and one of the Fe II sites after heat treatment, resulting in the generation of a new phase, {[(Tp 4-Me)Fe II(CN) 3][(Tp 4-Me)Fe III(CN) 3] 8 [Fe IIIFe II3(trz-ph) 6]}⋅ [Ph 3PMe] 2⋅[(Tp 4-Me)Fe III(CN) 3] ( 1 a ). Structural and magnetic studies reveal that MMCT can tune the two-step SCO behavior of 1 into one-step SCO behavior of 1 a . Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin-transition materials with accessible multi-electronic states. 相似文献
6.
It is promising and challenging to manipulate the electronic structures and functions of materials utilizing both metal‐to‐metal charge transfer (MMCT) and spin‐crossover (SCO) to tune the valence and spin states of metal ions. Herein, a metallocyanate building block is used to link with a Fe II‐triazole moiety and generates a mixed‐valence complex {[(Tp 4‐Me)Fe III(CN) 3] 9[Fe II4(trz‐ph) 6]}?[Ph 3PMe] 2?[(Tp 4‐Me)Fe III(CN) 3] ( 1 ; trz‐ph=4‐phenyl‐4 H‐1,2,4‐triazole). Moreover, MMCT occurs between Fe III and one of the Fe II sites after heat treatment, resulting in the generation of a new phase, {[(Tp 4‐Me)Fe II(CN) 3][(Tp 4‐Me)Fe III(CN) 3] 8 [Fe IIIFe II3(trz‐ph) 6]}? [Ph 3PMe] 2?[(Tp 4‐Me)Fe III(CN) 3] ( 1 a ). Structural and magnetic studies reveal that MMCT can tune the two‐step SCO behavior of 1 into one‐step SCO behavior of 1 a . Our work demonstrates that the integration of MMCT and SCO can provide a new alternative for manipulating functional spin‐transition materials with accessible multi‐electronic states. 相似文献
7.
The clectrochemical behaviour of the complexes [Ru II(L)(CO) 2Cl 2], [Ru II(L)(CO)Cl 3][Me 4N] and [Ru II(L)(CO) 2(CH 3CN) 2][CF 3SO 3] 2 (L = 2,2′-bipyridine or 4,4′-isopropoxycarbonyl-2,2′-bipyridine) has been investigated in CH 3CN. The oxidation of [Ru(L)(CO) 2Cl 2] produces new complexes [Ru III(L)(CO)(CH 3CN) 2Cl] 2+ as a consequence of the instability of the electrogenerated transient Ru III species [Ru III(L)(CO) 2Cl 2] +. In contrast, the oxidation of [Ru II(L)(CO)Cl 3][Me 4N] produces the stable [Ru III(L)(CO)Cl 3] complex. In contrast [Ru II(L)(CO) 2(CH 3CN) 2][CF 3SO 3] 2 is not oxidized in the range up to the most positive potentials achievable. The reduction of [Ru II(L)(CO) 2Cl 2] and [Ru II(L)(CO) 2(CH 3CN) 2][CF 3SO 3] 2 results in the formation of identical dark blue strongly adherent electroactive films. These films exhibit the characteristics of a metal-metal bond dimer structure. No films are obtained on reduction of [Ru II(L)(CO)Cl 3][Me 4N]. The effect of the substitution of the bipyridine ligand by electron-withdrawing carboxy ester groups on the electrochemical behaviour of all these complexes has also been investigated. 相似文献
8.
A cyanide-bridged Fe III–Fe II mixed-valence assembly, [Fe III(salen)] 2[Fe II(CN) 5NO] [salen = N, N-ethylene bis(salicylideneiminato)dianion], prepared by slow diffusion of an aqueous solution of Na 2[Fe(CN) 5NO] · 2H 2O and a MeOH solution of [Fe(salen)NO 3] in an H tube, has been characterized by X-ray structure analysis, i.r. spectra and magnetic measurements. The product assumes a two-dimensional network structure consisting of pillow-like octanuclear [—Fe II—CN—Fe III—NC—] 4 units with dimensions: Fe II—C = 1.942(7) Å, C—N = 1.139(9) Å, Fe III—N = 2.173(6) Å, Fe II—C—N = 178.0(6)°, Fe III—N—C = 163.4(6)°. The Fe II—N—O bond angle is linear (180.0°). The variable temperature magnetic susceptibility, measured in the 4.8–300 K range, indicates the presence of a weak intralayer antiferromagnetic interaction and gives an Fe III–Fe III exchange integral of –0.033 cm –1. 相似文献
9.
The present work describes the development of a selective, sensitive and stable sensing microsensor for scanning electrochemical microscopy (SECM) to measure H 2O 2 during electrochemical reduction of oxygen. The microsensor is based on graphene and Poly(3,4‐ethylenedioxythiophene) composite as support to iron (III) hexacyanoferrate (II) (PEDOT/graphene/Fe III4[Fe II(CN) 6] 3 microsensor). The electrochemical properties of the PEDOT/graphene/Fe III4[Fe II(CN) 6] 3 microsensor were investigated by cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM). The PEDOT/graphene/Fe III4[Fe II(CN) 6] 3 microsensor showed an excellent electrocatalytic activity toward hydrogen peroxide (H 2O 2) reduction with a diminution of the overpotential of about 500 mV in comparison to the process at a bare gold microelectrode. The microsensor presented excellent performance for two dimensional mapping of H 2O 2 by SECM in 0.1 mol L ?1 phosphate buffer solution (pH 7.0). Under optimized conditions, a linear response range from 1 up to 1000 µmol L ?1 was obtained with a sensitivity of 0.08 nA L µmol ?1 and limit of detection of 0.5 µmol L ?1. 相似文献
10.
Polycrystalline Co 0.75Ni 0.75[Fe(CN) 6]?·?XH 2O was prepared by coprecipitation. The coprecipitated powder was annealed in vacuum at 80°C, 100°C, and 130°C. Variation of microstructural and magnetic properties with different annealed temperatures was studied by Fourier-transform infrared, X-ray diffraction, and magnetization measurements. The differences in magnetic phase transition temperature, coercivity, remanence, and effective magnetization were studied in detail. The magnetic contribution mainly results from Fe III–CN–Co II/Ni II and Fe III–NC–Co II/Ni II because Fe II–CN–Co III/Ni II carries no net spin. After annealing at 130°C, the microstructures Fe III–CN–Co II/Ni II and Fe III–NC–Co II/Ni II convert to Fe II–CN–Co III/Ni II. Differences in magnetic properties may be attributed to heat-induced microstructural changes. 相似文献
11.
采用直接混合法制得平均尺寸小于50 nm的六氰合铁酸钴纳米粒子,元素分析表明其计量学分子式为K 0.2Co 1.4[Fe(CN) 6]•xH 2O,红外光谱证明此物质是由铁磁性的Co II1.5[Fe III(CN) 6]和反铁磁性的KCo III[Fe II(CN) 6]组成,并含有一定量的结晶水。用六氰合铁酸钴纳米粒子修饰的玻碳电极具有良好的稳定性和可逆的循环伏安行为,其电化学特征受溶液中配对阳离子种类和支持电解质浓度的影响。作为电极表面的媒介体,该薄膜对多巴胺的氧化还原具有电催化作用。 相似文献
12.
A polynuclear electronically/ionically (redox) conducting mixed-valent inorganic material such as nickel(II) hexacyanoferrate(II,III), NiHCF, was considered for potential application as a redox mediator (charge relay) in dye-sensitized solar cell (DSSC). The NiHCF redox reactions were found fast and reversible not only when the system was studied as thin film exposed to an aqueous supporting electrolyte but also as bulk material (pasted powder) in solid state, i.e., in the absence of contact with external liquid electrolyte phase. Usefulness of NiHCF material was diagnosed using conventional electroanalytical approaches, solid-state voltammetric methodology, as well as the dynamic electrochemical impedance spectroscopy technique that permitted monitoring of impedance spectra under potentiodynamic conditions. The material was utilized in a mixed-valent state, i.e., as a mixture of K4NiII[FeII(CN)6] and K3NiII[FeIII(CN)6] in which iron(II) and iron(III) sites were at the 1:1 ratio. Under such conditions, dynamics of electron-hopping between mixed-valent iron sites was maximized. Our DSSC utilized cis–dithiocyanoatobis(4,4′-dicarboxylic acid-2,2′-bipyridine) ruthenium(II) dye (N3) adsorbed onto TiO2 semiconductor and NiHCF as redox mediator. Although performance of our DSSC was not optimized in terms of the NiHCF film thickness and morphology, as well as lower photocurrents in comparison to those characteristic of the iodine/iodide based DSSC were obtained, our system yielded readily fairly high open-circuit photovoltages on the level of 800 mV. An important issue was that the formal potential of NiHCF was more positive relative to the potential of the iodide/triiodide couple while being still more negative than that equivalent to the ground state of the N3 dye. Thus, NiHCF mediator was able to regenerate the dye. 相似文献
13.
A polynuclear electronically/ionically (redox) conducting mixed-valent inorganic material such as nickel(II) hexacyanoferrate(II,III), NiHCF, was considered for potential application as a redox mediator (charge relay) in dye-sensitized solar cell (DSSC). The NiHCF redox reactions were found fast and reversible not only when the system was studied as thin film exposed to an aqueous supporting electrolyte but also as bulk material (pasted powder) in solid state, i.e., in the absence of contact with external liquid electrolyte phase. Usefulness of NiHCF material was diagnosed using conventional electroanalytical approaches, solid-state voltammetric methodology, as well as the dynamic electrochemical impedance spectroscopy technique that permitted monitoring of impedance spectra under potentiodynamic conditions. The material was utilized in a mixed-valent state, i.e., as a mixture of K 4Ni II[Fe II(CN) 6] and K 3Ni II[Fe III(CN) 6] in which iron(II) and iron(III) sites were at the 1:1 ratio. Under such conditions, dynamics of electron-hopping between mixed-valent iron sites was maximized. Our DSSC utilized cis–dithiocyanoatobis(4,4??dicarboxylic acid-2,2??bipyridine) ruthenium(II) dye (N3) adsorbed onto TiO 2 semiconductor and NiHCF as redox mediator. Although performance of our DSSC was not optimized in terms of the NiHCF film thickness and morphology, as well as lower photocurrents in comparison to those characteristic of the iodine/iodide based DSSC were obtained, our system yielded readily fairly high open-circuit photovoltages on the level of 800?mV. An important issue was that the formal potential of NiHCF was more positive relative to the potential of the iodide/triiodide couple while being still more negative than that equivalent to the ground state of the N3 dye. Thus, NiHCF mediator was able to regenerate the dye. 相似文献
14.
A series of octahedral Ru II/Ru III complexes of the type [Ru(Y)(CO)(BAX)(PPh 3) 2] and [RuCl 2(BAX)(PPh 3) 2] (Y = H or Cl; BAX = benzaldehydeacetylhydrazone anion; X = H, Me, OMe, OH, Cl or NO 2) have been prepared and characterised by spectral, magnetic and cyclic voltammetric studies. The Ru II complexes are low spin diamagnetic (S = 0) whereas the Ru III complexes are low spin and paramagnetic (S = 1/2). These Ru II and Ru III 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 Ru III 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 Ru III complexes indicates an asymmetry in the electronic environment around the Ru atom. Ru II complexes in CH 2Cl 2 show an irreversible Ru II/III redox couple at ca. 0.9–0.5 V, while the Ru III 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
15.
Thermolysis of cyano complexes. VII. On the thermal decomposition of hexacyanocobaltate(III); ligand exchange during thermolysis The thermal decomposition of hexacyanocobaltates(III) yields, as products of successive intramolecular redox reactions, first dicyan and Co II(Co III)-complexes, then Co II[Co II]-complexes and simple Co II(CN) 2, respectively, and finally Co ICN and elemental Co, respectively. All the compounds of the [Co III(NH 3) 6] 3+ cation with the cyanometallate anions of Co, Fe, Cr, Mn, Ni, Mo yield the same DTA curve as [Co(NH 3) 6][Co(CN) 6] does; in the case of Ni and Cr, which are capable of forming ammine complexes, simultaneous mutual ligand exchange occurs. 相似文献
16.
The use of the [Fe III(AA)(CN) 4] ? complex anion as metalloligand towards the preformed [Cu II(valpn)Ln III] 3+ or [Ni II(valpn)Ln III] 3+ heterometallic complex cations (AA=2,2′‐bipyridine (bipy) and 1,10‐phenathroline (phen); H 2valpn=1,3‐propanediyl‐bis(2‐iminomethylene‐6‐methoxyphenol)) allowed the preparation of two families of heterotrimetallic complexes: three isostructural 1D coordination polymers of general formula {[Cu II(valpn)Ln III(H 2O) 3(μ‐NC) 2Fe III(phen)(CN) 2 {(μ‐NC)Fe III(phen)(CN) 3}]NO 3 ? 7 H 2O} n (Ln=Gd ( 1 ), Tb ( 2 ), and Dy ( 3 )) and the trinuclear complex [Cu II(valpn)La III(OH 2) 3(O 2NO)(μ‐NC)Fe III(phen)(CN) 3] ? NO 3 ? H 2O ? CH 3CN ( 4 ) were obtained with the [Cu II(valpn)Ln III] 3+ assembling unit, whereas three isostructural heterotrimetallic 2D networks, {[Ni II(valpn)Ln III(ONO 2) 2(H 2O)(μ‐NC) 3Fe III(bipy)(CN)] ? 2 H 2O ? 2 CH 3CN} n (Ln=Gd ( 5 ), Tb ( 6 ), and Dy ( 7 )) resulted with the related [Ni II(valpn)Ln III] 3+ precursor. The crystal structure of compound 4 consists of discrete heterotrimetallic complex cations, [Cu II(valpn)La III(OH 2) 3(O 2NO)(μ‐NC)Fe III(phen)(CN) 3] +, nitrate counterions, and non‐coordinate water and acetonitrile molecules. The heteroleptic {Fe III(bipy)(CN) 4} moiety in 5 – 7 acts as a tris‐monodentate ligand towards three {Ni II(valpn)Ln III} binuclear nodes leading to heterotrimetallic 2D networks. The ferromagnetic interaction through the diphenoxo bridge in the Cu II?Ln III ( 1 – 3 ) and Ni II?Ln III ( 5 – 7 ) units, as well as through the single cyanide bridge between the Fe III and either Ni II ( 5 – 7 ) or Cu II ( 4 ) account for the overall ferromagnetic behavior observed in 1 – 7 . DFT‐type calculations were performed to substantiate the magnetic interactions in 1 , 4 , and 5 . Interestingly, compound 6 exhibits slow relaxation of the magnetization with maxima of the out‐of‐phase ac signals below 4.0 K in the lack of a dc field, the values of the pre‐exponential factor ( τo) and energy barrier ( Ea) through the Arrhenius equation being 2.0×10 ?12 s and 29.1 cm ?1, respectively. In the case of 7 , the ferromagnetic interactions through the double phenoxo (Ni II–Dy III) and single cyanide (Fe III–Ni II) pathways are masked by the depopulation of the Stark levels of the Dy III ion, this feature most likely accounting for the continuous decrease of χM T upon cooling observed for this last compound. 相似文献
17.
To investigate how the central metalloligand geometry influences distant or vicinal metal‐to‐metal charge‐transfer (MMCT) properties of polynuclear complexes, c is‐ and trans‐isomeric heterotrimetallic complexes, and their one‐ and two‐electron oxidation products, cis/ trans‐ [Cp(dppe)Fe IINCRu II(phen) 2CN‐Fe II(dppe)Cp][PF 6] 2 ( cis/ trans‐ 1 [PF 6] 2), cis/ trans‐[Cp(dppe)Fe IINCRu II(phen) 2CNFe III‐(dppe)Cp][PF 6] 3 ( cis/ trans‐ 1 [PF 6] 3) and cis/ trans‐[Cp(dppe)Fe IIINCRu II(phen) 2CN‐Fe III(dppe)Cp][PF 6] 4 ( cis/ trans‐ 1 [PF 6] 4) have been synthesized and characterized. Electrochemical measurements show the presence of electronic interactions between the two external Fe II atoms of the cis‐ and trans‐isomeric complexes cis/ trans‐ 1 [PF 6] 2. The electronic properties of all these complexes were studied and compared by spectroscopic techniques and TDDFT//DFT calculations. As expected, both mixed valence complexes cis/ trans‐ 1 [PF 6] 3 exhibited different strong absorption signals in the NIR region, which should mainly be attributed to a transition from an MO that is delocalized over the Ru II‐CN‐Fe II subunit to a Fe III d orbital with some contributions from the co‐ligands. Moreover, the NIR transition energy in trans‐ 1 [PF 6] 3 is lower than that in cis‐ 1 [PF 6] 3, which is related to the symmetry of their molecular orbitals on the basis of the molecular orbital analysis. Also, the electronic spectra of the two‐electron oxidized complexes show that trans‐ 1 [PF 6] 4 possesses lower vicinal Ru II→Fe III MMCT transition energy than cis‐ 1 [PF 6] 4. Moreover, the assignment of MMCT transition of the oxidized products and the differences of the electronic properties between the cis and trans complexes can be well rationalized using TDDFT//DFT calculations. 相似文献
18.
Hereby we present the synthesis of several ruthenium(II) and ruthenium(III) dithiocarbamato complexes. Proceeding from the Na[ trans‐Ru III(dmso) 2Cl 4] ( 2 ) and cis‐[Ru II(dmso) 4Cl 2] ( 3 ) precursors, the diamagnetic, mixed‐ligand [Ru IIL 2(dmso) 2] complexes 4 and 5 , the paramagnetic, neutral [Ru IIIL 3] monomers 6 and 7 , the antiferromagnetically coupled ionic α‐[Ru III2L 5]Cl complexes 8 and 9 as well as the β‐[Ru III2L 5]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‐[Ru III2(dmdt) 5]BF 4 ? CHCl 3 ? CH 3CN and of the novel [Ru IIL 2(dmso) 2] complexes were also determined and discussed. For both the mono‐ and dinuclear Ru II and Ru III 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 Ru III 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 Ru II complexes 4 and 5 has been observed. 相似文献
19.
A mixed-valence {Mn II3Mn IIIFe II2Fe III2} cyanide-bridged molecular cube hosting a caesium cation, Cs⊂{Mn 4Fe 4}, was synthesized and structurally characterized by X-ray diffraction. Cyclic-voltammetry measurements show that its electronic state can be switched between five different redox states, which results in a remarkable electrochromic effect. Magnetic measurements on fresh samples point to the occurrence of a spin-state change near room temperature, which could be ascribed to a metal-to-metal electron transfer converting the {Fe II−CN−Mn III} pair into a {Fe III−CN−Mn II} pair. This feature was only previously observed in the polymeric MnFe Prussian-blue analogues (PBAs). Moreover, this novel switchable molecule proved to be soluble and stable in organic solvents, paving the way for its integration into advanced materials. 相似文献
20.
A family of CoFe Prussian blue analogues CxCo 4[Fe(CN) 6] (8+x/3)□ (4–x)3 ( x = amount of alkali cation inserted per conventional cell, C = Na, K, Rb, Cs; □ = [Fe(CN) 6] vacancy) have been synthesized and characterized. Their photomagnetic properties have been investigated by magnetic measurements before and after irradiation and X-ray diffraction under continuous irradiation. We show that the photo-induced magnetism depends on several parameters: ( i) the amount of Co III–Fe II diamagnetic excitable pairs per cell; ( ii) the amount of [Fe(CN) 6] vacancies, and ( iii) the amount and nature of the alkali cations per cell. We evidence a discontinuity in the properties' change when the amount of alkali cation x varies, around x = 1. For x < 1, there is an excitation of diluted Co III–Fe II diamagnetic pairs in a phase mainly composed of magnetic Co II–Fe III entities within the same structural phase through a second-order continuous transformation. For x ≥ 1, the formation of domains mainly composed of Co II–Fe III* metastable magnetic pairs in a phase mainly composed of Co III–Fe II diamagnetic ones through a first-order discontinuous transition is observed. The study points out that sodium derivatives are more efficient than the others. Among them, Na 1Co 4[Fe(CN) 6] 3□ 1 is predicted to be the most efficient one. To cite this article: A. Bleuzen et al., C. R. Chimie 6 (2003). 相似文献
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