共查询到20条相似文献,搜索用时 46 毫秒
1.
S. Max Bessey 《Inorganica chimica acta》2010,363(1):279-7422
The synthesis of triethylphosphine gold(I) 4-nitrobenzenethiolate, Et3PAu(SC6H4NO2-4), is reported. Et3PAu(SC6H4NO2-4) displays a low energy visible electronic absorption band which is solvent dependent: EtOH (λmax = 385 nm), acetonitrile (λmax = 391 nm), THF (λmax = 395 nm), and DMSO (λmax = 402 nm). The corresponding low energy visible electronic absorption band of 4-nitrobenzenethiolate, 4-NO2C6H4S− also shows solvent dependency: acetonitrile, (λmax = 484 nm), DMSO (λmax = 502 nm), dimethylformamide (λmax = 505 nm). The positive solvatochromic shifts for Et3PAu(SC6H4NO2-4) and 4-NO2C6H4S− are consistent with an intraligand (IL) charge transfer transition, i.e. π(S) → ∗π (C6H4NO2-4) or n(S) → ∗π (C6H4NO2-4). Assignment of 4-NO2C6H4S− was aided by a DFT calculation. 相似文献
2.
David F. Dye 《Inorganica chimica acta》2008,361(4):1177-1186
The electronic and vibrational Raman spectra of octa-substituted (R = -SC10H21) Co- and Cu-porphyrazines are reported in their solid-state, mesophase, and isotropic liquid forms, as well as in THF solution. Their electronic spectra are composed of traditional Soret (CuS10 = 355 nm, CoS10 = 347 nm) and lower energy Q-bands (CuS10 = 669 nm, CoS10 = 639 nm), as well as a weaker, functionality-specific sulfur n → porphyrin π∗ feature (CuS10 = 500 nm; CoS10 = 447 nm). In contrast to the broad Q-band for CoS10 in all three neat phases, the lower energy analogue for CuS10 is markedly sharper in the microcrystalline state, but similarly broadens in the mesophase, indicative of long range macrocycle π-π interactions that persist even into the liquid state. The resonance (λ = 647 nm) and off-resonance (λ = 785 nm) Raman spectra of these materials in each phase exhibit four diagnostic vibrations; the Cα-Nm stretch (∼1540-1553) cm−1, Cβ-Cβ stretch (∼1450 cm−1), Cα-Cβ-Np stretch (∼1300-1315 cm−1), and Cα-Cβ stretch (∼1070 cm−1). For CoS10, these vibrations systematically shift to lower energy upon melting, while those for CuS10 collapse to degenerate sets. The differences in the electronic and vibrational profiles as a function of temperature suggest that the mesophase structure is governed by strong axial Co-S interactions for CoS10 which template macrocycle π-π stacking, while for CuS10 the same contacts exist, but they are phase dependent and markedly weaker. These inter-porphyrazine interactions are, therefore, responsible for the distinct differences in the melting and clearing temperatures of their respective mesophases. Finally, based on these diagnostic spectroscopic signatures, a photo-thermal, phase-switching mechanism is demonstrated with λ = 785 nm excitation at reduced temperatures, leading to the ability to spectrally monitor and phase change with a single photon source. 相似文献
3.
The synthesis of the mixed ligand mono metallic [Ru(dpop′)(tppz)]2+ and bimetallic [(dpop′)Ru(tppz)Ru(dpop′)]4+ (dpop′ = dipyrido(2,3-a:3′,2′-j)phenazine; tppz = 2,3,5,6 tetra-(2-pyridyl)pyrazine) complexes is described. The [Ru(dpop′)(tppz)]2+ complex display an intense absorption at 518 nm which is assigned to a Ru(dπ) → dpop′ (π∗) MLCT transition, and at 447 nm which is assigned to a Ru(dπ) → tppz(π∗) MLCT transition. It undergoes emission at RT in CH3CN with λem = 722 nm. The bimetallic [(dpop′)Ru(tppz)Ru(dpop′)]4+ complex shows a low energy absorption shoulder near 635 nm assigned to a Ru(dπ) → tppz(π∗) MLCT transition and an intense peak at 542 nm due to Ru(dπ) → dpop′ (π∗) MLCT transition. The bimetallic complex also emits at RT in CH3CN with λem = 785 nm. Cyclic voltammetry shows reversible Ru+2/+3 oxidations at 1.68 V for the monometallic complex and Ru+2/+3 oxidation couples at +1.94 and +1.70 V for the bimetallic complex. 相似文献
4.
Krzysztof L. Hyrc Akwasi Minta P. Rogelio Escamilla Patrick P.L. Chan Xenia A. Meshik Mark P. Goldberg 《Cell calcium》2013
Although many synthetic calcium indicators are available, a search for compounds with improved characteristics continues. Here, we describe the synthesis and properties of Asante Calcium Red-1 (ACR-1) and its low affinity derivative (ACR-1-LA) created by linking BAPTA to seminaphthofluorescein. The indicators combine a visible light (450–540 nm) excitation with deep-red fluorescence (640 nm). Upon Ca2+ binding, the indicators raise their fluorescence with longer excitation wavelengths producing higher responses. Although the changes occur without any spectral shifts, it is possible to ratio Ca2+-dependent (640 nm) and quasi-independent (530 nm) emission when using visible (<490 nm) or multiphoton (∼780 nm) excitation. Therefore, both probes can be used as single wavelength or, less dynamic, ratiometric indicators. Long indicator emission might allow easy [Ca2+]i measurement in GFP expressing cells. The indicators bind Ca2+ with either high (Kd = 0.49 ± 0.07 μM; ACR-1) or low affinity (Kd = 6.65 ± 0.13 μM; ACR-1-LA). Chelating Zn2+ (Kd = 0.38 ± 0.02 nM) or Mg2+ (Kd ∼ 5 mM) slightly raises and binding Co2+ quenches dye fluorescence. New indicators are somewhat pH-sensitive (pKa = 6.31 ± 0.07), but fairly resistant to bleaching. The probes are rather dim, which combined with low AM ester loading efficiency, might complicate in situ imaging. Despite potential drawbacks, ACR-1 and ACR-1-LA are promising new calcium indicators. 相似文献
5.
The synthesis and crystal structure of two new complexes (Zn and Mn) containing tetrazolyl ligands are described. In situ [2+3] cycloaddition reactions of fipronil, (fipronil = (±)-5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile) with sodium azide in the presence of ZnCl2 or MnCl2 as a Lewis acid (Demko-Sharpless tetrazole synthesis method) under hydrothermal (solvothermal) reaction conditions gave [Zn(L)2](H2O)2] · H2O, 1 and [Mn(L)2](H2O)2] · H2O, 2, (HL = (±)-5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazole-3-tetrazole). The central metals in both complexes are six coordinated, which connected by two water molecules, two nitrogen atoms from different tetrazolyl groups and two nitrogen atoms from pyrazolyl rings respectively. Photoluminescence studies reveal that both title complexes exhibit strong blue fluorescent emissions at λmax = 383 nm for 1 and 411 nm for 2 respectively in the solid state at room temperature. 相似文献
6.
Soma Mukherjee Chandrama Basu Asoke P. Chattopadhyay Utpal Ghosh 《Inorganica chimica acta》2010,363(12):2752-139
A blue luminescent dichlorido-bridged dinuclear copper(II) (S = 1/2) complex, [CuII2(HL)2(μ-Cl)2]·2H2O, 1a was synthesized with the 1:1 reaction of the acyclic tridentate salicylaldehyde 2-pyridyl hydrazone ligand, HL, 1. The complex 1a displays multiple bands in the visible region (400-470 nm). The association constant (Kass, UV-Vis) was found to be 1.186 × 104 for 1a at 298 K. The copper(II)-copper(III) oxidation potential lies near 0.32 V versus Ag/AgCl electrode. On excitation at 390 nm, the ligand 1 strongly emits at 444 nm due to an intraligand 1(π-π∗) transition. Upon complexation with copper(II) the emission peak is slightly red shifted (λex 390 nm, λem 450 nm, F/F0 0.81) with little quenching. Molecular structure of 1a (Cu···Cu 3.523 Å) has been determined by single crystal X-ray diffraction studies. DFT and TDDFT calculations strongly support the spectral behavior of the ligand and the complex. The complex 1a exhibits a strong interaction towards DNA as revealed from the Kb (intrinsic binding constant) 2.05 × 104 M−1 and Ksv (Stern-Volmer quenching constant) 2.47 values. The complex exhibits cytotoxic effect and the LD50 value for HeLa cells was calculated as 5.44 μM at which the cell cycle was arrested at G2/M phase. 相似文献
7.
Carrick M. Eggleston Janos Vörös Brian H. Lower Patricia J.S. Colberg 《Inorganica chimica acta》2008,361(3):769-777
Dissimilatory iron-reducing bacteria transfer electrons to solid ferric respiratory electron acceptors. Outer-membrane cytochromes expressed by these organisms are of interest in both microbial fuel cells and biofuel cells. We use optical waveguide lightmode spectroscopy (OWLS) to show that OmcA, an 85 kDa decaheme outer-membrane c-type cytochrome from Shewanella oneidensis MR-1, adsorbs to isostructural Al2O3 and Fe2O3 in similar amounts. Adsorption is ionic-strength and pH dependent (peak adsorption at pH 6.5-7.0). The thickness of the OmcA layer on Al2O3 at pH 7.0 [5.8 ± 1.1 (2σ) nm] from OWLS is similar, within error, to that observed using atomic force microscopy (4.8 ± 2 nm). The highest adsorption density observed was 334 ng cm−2 (2.4 × 1012 molecules cm−2), corresponding to a monolayer of 9.9 nm diameter spheres or submonolayer coverage by smaller molecules. Direct electrochemistry of OmcA on Fe2O3 electrodes was observed using cyclic voltammetry, with cathodic peak potentials of −380 to −320 mV versus Ag/AgCl. Variations in the cathodic peak positions are speculatively attributed to redox-linked conformation change or changes in molecular orientation. OmcA can exchange electrons with ITO electrodes at higher current densities than with Fe2O3. Overall, OmcA can bind to and exchange electrons with several oxides, and thus its utility in fuel cells is not restricted to Fe2O3. 相似文献
8.
Swamy Maloth 《Inorganica chimica acta》2011,372(1):407-88
Synthesis, physical properties and X-ray structure of a hydrated tetranuclear copper(II) complex [Cu4(μ-diph)2(μ-H2O)2(O2CCH3)4(H2O)2]·4H2O with N,N′-bis(picolinoyl)hydrazine (H2diph) are reported. The centrosymmetric complex has two types of copper(II) centres with distorted square-pyramidal N2O3 coordination spheres. The dinucleating trans planar diph2− ligands are parallel to each other and act as N2O-donor to one metal centre and N2-donor to the other metal centre. The complex has a rectangular {Cu4(μ-N-N)2(μ-OH2)2} core with Cu···Cu distances as 4.834(1) and 3.762(1) Å. Solid state as well as solution electronic spectra show several transitions in the wavelength range 700-280 nm. The room temperature (298 K) solid state magnetic moment is 3.55 μB. The powder EPR spectra at 298 and 130 K are very similar and axial (g∥ = 2.25 and g⊥ = 2.08) in character. 相似文献
9.
Mónica M. Vergara Florencia Fagalde Jan Fiedler Monika Sieger 《Inorganica chimica acta》2010,363(1):163-2714
New diruthenium complexes (PPN)4[(NC)4Ru(μ-bptz)Ru(CN)4], (PPN)41, and [(bpy)2Ru(μ-bptz)Ru(CN)4], 2, (PPN+ = bis(triphenylphospine)iminium; bptz = 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine; bpy = 2,2′-bipyridine), were synthesised and characterised by spectroscopic and electrochemical techniques. The comproportionation constant Kc = 107.0 of the mixed-valent species [(NC)4Ru(μ-bptz)Ru(CN)4]3− as obtained by oxidation of 14− in CH3CN is much lower than the Kc = 1015.0 previously detected for [(H3N)4Ru(bptz)Ru(NH3)4]5+, reflecting the competition between CN− and bptz for the π-electron density of the metals. Comparison with several other bptz-bridged diruthenium(II,III) complexes reveals an approximate correlation between Kc and the diminishing effective π acceptor capacity of the ancillary terminal ligands. In addition to the intense MLCT absorption at λmax = 624 nm, the main IVCT (intervalence charge transfer) band of 13− was detected by spectroelectrochemistry at λmax = 1695 nm (in CH3CN; ε = 3200 M−1 cm−1). The experimental band width at half-height, Δν1/2 = 2700 cm−1, is slightly smaller than the theoretical value Δν1/2 = 3660 cm−1, calculated from the Hush approximation for Class II mixed-valent species. In agreement with comparatively moderate metal-metal coupling, the mixed-valent intermediate 13− was found to be EPR silent even at 4 K. The unsymmetrical mixed-valent complex [(bpy)2RuII(μ-bptz)RuIII(CN)4]+, obtained in situ by bromine oxidation of 2 in CH3CN/H2O, displays a broad NIR absorption originating from an IVCT transition at λmax = 1075 nm (ε ≈ 1000 M−1 cm−1, Δν1/2 ≈ 4000 cm−1). In addition, the lifetime of the excited-state of the mononuclear precursor complex [Ru(bptz)(CN)4]2− was measured in H2O by laser flash photolysis; the obtained value of τ = 19.6 ns reveals that bptz induces a metal-to-ligand electronic delocalisation effect intermediate between that induced by bpy and bpz (bpz = 2,2′-bipyrazine) in analogous tetracyanoruthenium complexes. 相似文献
10.
Michael W. Cooke 《Inorganica chimica acta》2008,361(8):2259-2269
We herein describe the synthesis and characterization of a series of homoleptic, Ru(II) complexes bearing peripheral carboxylic acid functionality based upon the novel ligand 4′-(4-carboxyphenyl)-4,4″-di-(tert-butyl)tpy (L1), as well as 4′-(4-carboxyphenyl)tpy (L2) and 4′-(carboxy)tpy (L3) (where tpy = 2,2′: 6′,2″-terpyridine). Inspection of the metal-based oxidations (E1/2 = 1.22-1.42 V) indicates an anodic shift (∼0.2 V) for (L3)2Ru2+ (3b) (E1/2 = 1.40 V) relative to (L2)2Ru2+ (2b) (E1/2 = 1.22 V). The metal-based oxidation (E1/2 = 1.22 V) and ligand-based reductions (E1/2 = −1.25 to −1.52 V) of (L1)2Ru2+ (1) are essentially invariant relative to those of the structural analogue 2b (PF6)2, which suggests no significant electronic effect caused by the tert-butyl groups. This is supported by invariance in the metal-to-ligand charge transfer bands in both the electronic absorption (494-489 nm) and emission spectra (654-652 nm). However, contrary to 2b, complex 1 is both very soluble and exhibits a highly porous solid-state structure with internal cavity dimensions of 15 Å × 14 Å due to the preclusion of inter-annular interactions by the bulky tert-butyl substituents. 相似文献
11.
The nitrosyl complex [Cr(dmso)5(NO)](PF6)2 (1) (dmso = dimethyl sulfoxide) has been prepared by the solvolysis of [Cr(NCCH3)5(NO)](PF6)2 in neat dmso. The optical absorption spectrum of 1 in dmso shows maxima at 734, 567, 450, 413, and 337 nm. Continuous photolysis of 1 with λ = 365-580 nm light in dmso solution results in a release of NO with quantum yield, Φ, in the range 0.034-0.108 mol Einstein−1. Irradiation of a deoxygenated CH3CN solution of [Cr(NCCH3)5(NO)](PF6)2 in the presence of excess of [Fe(S2CNEt2)2] results in a transfer of NO to the iron centre as shown from the characteristic EPR spectrum of [Fe(S2CNEt2)2(NO)] with Aiso(14N) = 12.2 × 10−4 cm−1. The EPR parameters of 1 were determined: giso, g‖ and g⊥ : 1.96725, 1.91881(4) and 1.992763(2); Aiso(53Cr), A‖ (53Cr) and A⊥(53Cr): 22.8 × 10−4, 39 × 10−4 and 15.8 × 10−4 cm−1; Aiso(14N), A‖ (14N) and A⊥(14N): 5.9 × 10−4, 2 × 10−4 and 7.540(4) × 10−4 cm−1. 相似文献
12.
Kamran Akhbari 《Inorganica chimica acta》2009,362(6):1692-1628
[Tl3(μ-1,2,3-btc)]n (1,2,3-H3btc = 1,2,3-benzenetricarboxylic acid) (1), [Tl2(μ-1,3,5-Hbtc)(H2O)]n (1,3,5-H3btc = 1,3,5-benzenetricarboxylic acid) (2) and [Tl4(μ-1,2,4,5-btc)]n (1,2,4,5-H4btc = 1,2,4,5-benzenetetracarboxylic acid) (3), three new TlI coordination polymers have been synthesized, characterized by elemental analysis and IR spectroscopy and their structures determined by single-crystal X-ray diffraction. The thermal stability of compounds 1-3 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The single-crystal X-ray analysis of compounds 1-3 shows that the compounds are structurally diverse showing three-dimensional coordination polymers. The carboxylic groups of the ligands 1,2,3-btc3−, 1,3,5-Hbtc2− and 1,2,4,5-btc4− in the new TlI coordination polymers are not chelated and only act as bridging groups. In compounds 1-3, the lone pair of Tl(I) atoms is ‘active’ in the solid state and the coordination spheres are hemisphere type. Solution state luminescent spectra of compound 2 indicate intense fluorescent emissions at ca. 400 nm. 相似文献
13.
Lanthanide complexes are of great importance for their prospective applications in wide range of science and technology. Chiral lanthanide complexes can constitute stereo-discriminating probes in biological media, owing to the luminescent properties of the rare-earth ions. Sensitized emission with narrow bandwidth, having fast radiation rate and high emission quantum efficiency are the main perspective for synthesizing the complexes. Attention has been given on remarkable chirality with high dissymmetry factors (g = Δεext/εmax) of the complexes. For this purpose, beta-diketonato ligands with chiral BINAPO (1,1′-binapthyl phosphine oxide) ligand were chosen to achieve the goal. The complexes [Ln(TFN)3(S-BINAPO)](TFN = 4,4,4-trifluoro-1(2-napthyl)-1,3-butanedione), [Ln(HFT)3(S-BINAPO)] (HFT = 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione) and [Ln(HFA)3(S-BINAPO)](hfa = hexafluoroacetylacetonate) (where Ln = Yb, Eu) were synthesized. The complex, [Eu(TFN)3(S-BINAPO)] gives strong red emission at 615 nm with narrow emission band (<10 nm) when excited by 465 nm light with quantum efficiency 86%. The dissymmetry factors (g = Δεext/εmax) corresponding to the 7F1 → 5D0 transition at 590 nm is 0.091 for [Eu(TFN)3(S-BINAPO)] and for [Yb(hfa)3(S-BINAPO)](hfa = hexafluoroacetylacetonate) corresponding to the 2F7/2 → 2F5/2 transitions is 0.12, are among the largest values for both Eu and Yb complexes to date, respectively. The Eu complexes, [Eu(HFT)3(S-BINAPO)] and [Eu(TFN)3(S-BINAPO)] are found to be spontaneously emissive, showing bright red emission, when placed in sunlight or even in the laboratory when light is switched on. 相似文献
14.
Carrie A. May John K. Grady Thomas M. Laue Maura Poli Paolo Arosio N. Dennis Chasteen 《Biochimica et Biophysica Acta (BBA)/General Subjects》2010
Background
Ferritin exhibits complex behavior in the ultracentrifuge due to variability in iron core size among molecules. A comprehensive study was undertaken to develop procedures for obtaining more uniform cores and assessing their homogeneity.Methods
Analytical ultracentrifugation was used to measure the mineral core size distributions obtained by adding iron under high- and low-flux conditions to horse spleen (apoHoSF) and human H-chain (apoHuHF) apoferritins.Results
More uniform core sizes are obtained with the homopolymer human H-chain ferritin than with the heteropolymer horse spleen HoSF protein in which subpopulations of HoSF molecules with varying iron content are observed. A binomial probability distribution of H- and L-subunits among protein shells qualitatively accounts for the observed subpopulations. The addition of Fe2+ to apoHuHF produces iron core particle size diameters from 3.8 ± 0.3 to 6.2 ± 0.3 nm. Diameters from 3.4 ± 0.6 to 6.5 ± 0.6 nm are obtained with natural HoSF after sucrose gradient fractionation. The change in the sedimentation coefficient as iron accumulates in ferritin suggests that the protein shell contracts ∼ 10% to a more compact structure, a finding consistent with published electron micrographs. The physicochemical parameters for apoHoSF (15%/85% H/L subunits) are M = 484,120 g/mol, ν? = 0.735 mL/g, s20,w = 17.0 S and D20,w = 3.21 × 10−7 cm2/s; and for apoHuHF M = 506,266 g/mol, ν? = 0.724 mL/g, s20,w = 18.3 S and D20,w = 3.18 × 10−7 cm2/s.Significance
The methods presented here should prove useful in the synthesis of size controlled nanoparticles of other minerals. 相似文献15.
By varying the solvents and temperatures under solvothermal conditions, two new magnesium based coordination networks were synthesized using 2,5-thiophenedicarbxoylate as a linker. Mg3(TDC)3(DMF)3 [1; TDC = 2,5 thiophenedicarboxylate; space group P21/c, a = 17.747(4) Å, b = 9.805(2) Å, c = 21.359(4) Å, β = 103.13(3)°] is constructed by a combination of magnesium polyhedral trimers, which are connected by the TDC2− linkers to form a 3-D network. Coordinated DMF molecules are present within the channels. Mg(TDC)(H2O)2 [2; space group Pnma, a = 7.296(4) Å, b = 17.760(4) Å, c = 6.6631(3) Å] is formed by 1-D chains of magnesium octahedra connected by the TDC2− linker. Water molecules are coordinated at the axial positions of the magnesium octahedra. Compound 1 is formed using DMF as the synthesis solvent at 180 °C, while compound 2 is formed using ethanol as the synthesis solvent at 100 °C. Both compounds show enhanced photoluminescence intensity when excited at 397 nm compared to the free TDC ligand, suggesting a charge transfer between the ligand and the magnesium metal center. 相似文献
16.
The present paper describes a new tripodal ligand containing imidazole and pyridine arms and its first cis-[RuIII(L)(Cl)2]ClO4 complex (1). The crystal structure of 1 shows RuIII in a distorted octahedral geometry, in which two chloride ions, cis-positioned to each other, are coordinated besides the four nitrogen atoms from the tetradentate ligand L. The cyclic voltammogram of 1 exhibits three redox processes at −67, +73 and +200 mV versus SCE, which are attributed to the RuIII/RuII couple in the cis-[RuIII(L)(Cl)2]+, cis-[RuII(L)(H2O)(Cl)]+ and cis-[RuII(L)(H2O)2]2+, respectively. After chemical reduction (Zn(Hg) or EuII) only the cis-[RuII(L)(H2O)2]2+ species is observed in the cyclic voltammetry. Complex 1 absorbs at 470 nm (ε=1.4×103 mol−1 L cm−1), 335 nm (ε=7.9×103 mol−1 L cm−1), 301 nm (ε=6.7×103 mol−1 L cm−1) and 264 nm (ε=9.9×103 mol−1 L cm−1), in water solution (CF3COOH, 0.01 mol L−1, μ=0.1 mol L−1 with CF3COONa). Spectroelectrochemical experiments show a decrease of the bands at 335 and 301 nm, which are attributed to LMCT transitions from the chloride to the RuIII center and the appearance of a broad band at 402 nm ascribed to MLCT transition from the RuII center to the pyridine ligand. The lability of the water ligands in the cis-[RuII(L)(H2O)2]2+ species has been investigated using the auxiliary ligand pyrazine. Reactions in the presence of stoichiometric and excess of pyrazine yield the same species, cis-[RuII(L)(H2O)(pz)]2+, which exhibits a reversible redox process at 493 mV versus SCE and absorbs at 438 nm (ε=5.1×103 mol−1 L cm−1) and 394 nm (ε=4.2×103 mol−1 L cm−1). Experiments performed with a large excess of pyrazine gave a specific rate constant k1=(2.8±0.5)×10−2 M−1 s−1, at 25 °C, in CF3COOH, 0.01 mol L−1, μ=0.1 mol L−1 (with CF3COONa). 相似文献
17.
Ali Canlier 《Inorganica chimica acta》2010,363(1):1-4850
Crystal structure of [ReO2(4-MeOpy)4][PF6] (4-MeOpy = 4-methoxypyridine) complex has been examined by the single crystal X-ray analytical method. This complex shows a trans-dioxo geometry (average Re-O bond length = 1.766(2) Å) and its equatorial plane is occupied by four 4-MeOpy molecules (average Re-N bond length = 2.156(4) Å). Electrochemical reaction of [ReO2(4-MeOpy)4]+ in CH3CN solution containing tetra-n-butylammonium perchlorate as a supporting electrolyte has been studied using cyclic voltammetry at 24 °C. Cyclic voltammograms show one redox couple around 0.65 V (Epa) and 0.58 V (Epc) [versus ferrocene/ferrocenium ion redox couple, (Fc/Fc+)]. Potential differences between two peaks (ΔEp) at scan rates in the range from 0.01 to 0.10 V s−1 are 65 mV, which is almost consistent with the theoretical ΔEp value (59 mV) for the reversible one electron transfer reaction at 24 °C. The ratio of anodic peak currents to cathodic ones is 1.04 ± 0.03 and the (Epa + Epc)/2 value is constant, 0.613 ± 0.001 V versus Fc/Fc+, regardless of the scan rate. Spectroelectrochemical experiments have also been carried out by applying potentials from 0.40 to 0.77 V versus Fc/Fc+ with an optically transparent thin layer electrode. It was found that the UV-visible absorption spectra show clear isosbestic points at 228, 276, and 384 nm, and that the electron stoichiometry is evaluated as 1.03 from the Nernstian plot. These results indicate that the [ReO2(4-MeOpy)4]+ complex is oxidized reversibly to the [ReO2(4-MeOpy)4]2+ complex. Furthermore, it was clarified that the [ReO2(4-MeOpy)4]2+ in CH3CN has the characteristic absorption bands at 236, 278, 330, 478, and 543 nm and their molar absorption coefficients are 4.3 × 104, 4.5 × 103, 1.0 × 104, and 6.1 × 103 M−1 cm−1 (M = mol dm−3), respectively. 相似文献
18.
The complex formation of curium(III) with adenosine 5′-triphosphate (ATP) was determined by time-resolved laser-induced fluorescence spectroscopy (TRLFS). The interaction between soluble species of curium(III) with ATP was studied at trace Cm(III) concentrations (3 × 10−7 M). The concentrations of ATP were varied between 6.0 × 10−7 and 1.5 × 10−4 M in the pH range of 1.5-7.0 using 0.154 M NaCl as background electrolyte.Three Cm-ATP species, MpHqLr, could be identified from the fluorescence emission spectra: (i) CmH2ATP+ with a peak maximum at 598.6 nm, (ii) CmHATP with a peak maximum at 600.3 nm, and (iii) CmATP− with a peak maximum at 601.0 nm. The formation constants of these complexes were calculated from TRLFS measurements to be log β121 = 16.86 ± 0.09, log β111 = 13.23 ± 0.10, and log β101 = 8.19 ± 0.16. The hydrated Cm-ATP species showed fluorescence lifetimes between 88 and 96 μs; whereas the CmATP− complex has a significantly longer fluorescence lifetime of 187 ± 7 μs. 相似文献
19.
Two cobalt(II) coordination polymers {[Co(SCN)2(3-bpit)2] · 2CH3OH}n (1) (3-bpit = N,N′-bis(3-pyridylformyl)imidazolidine-2-thione) and {[Co(SCN)2(4-bpit)2] · CH3OH · CH3CN}n (2) (4-bpit = N,N′-bis(4-pyridylformyl)imidazolidine-2-thione) have been synthesized for study of the third-order non-linear properties. X-ray crystal structural analyses reveal that the two polymers show the same topological motif: a ribbon of rings. Their third-order non-linear optical (NLO) properties in DMF solution have been studied by Z-scan techniques with a linearly polarized laser light (λ = 532 nm; pulse widths = 7 ns). Both of them exhibit strong self-focusing effect. The third-order NLO susceptibility χ(3) values are calculated to be 2.61 × 10−11 esu (1) and 2.76 × 10−11 esu (2), respectively. The values are comparable to those of the reported good NLO materials. 相似文献
20.
The ruthenium complexes, trans-[Ru(phen-NH-phen)(eina)2](PF6)2 and trans-[Ru(phen-NH-phen)(ina)2](PF6)2 where phen-NH-phen = N,N-bis(1,10-phenanthroline-2-yl)amine, ina = isonicotinic acid and eina = ethyl isonicotinate, have been synthesized and characterized by 1H NMR, elemental analysis, and IR spectroscopy. The compounds were non-emissive at room temperature, but displayed intense photoluminescence in 4:1 ethanol/methanol glasses at 77 K with corrected emission maximum at 570-580 nm. A quasi-reversible wave observed in cyclic voltammetry experiments was assigned to the RuIII/II couple, E° (trans-[Ru(phen-NH-phen)(eina)2)3+/2+ = +1.22 V versus Ag/AgCl. The trans-[Ru(phen-NH-phen)(ina)2](PF6)2 compound was found to bind to nanocrystalline TiO2 thin films from acetonitrile solution. Pulsed 532 nm excitation of trans-[Ru(phen-NH-phen)(ina)2](PF6)2 anchored to mesoporous nanocrystalline TiO2 thin films resulted in an absorption difference spectra consistent with the formation of an interfacial charge separated state trans-[RuIII (phen-NH-phen)(ina)2]+/TiO2 (e−). The formation of this state could not be time resolved, consistent with rapid excited state injection into the TiO2, kinj > 108 s−1. Comparative measurements with a thin film actinometer yielded an injection quantum yield (?inj) of 0.8. Charge recombination required milliseconds for completion and followed a bi-second-order equal concentration kinetic model with k1 = 1.0 × 108 s−1, and k2 = 3.0 × 105 s−1. In regenerative solar cells with 0.5 M LiI and 0.005 M I2 in acetonitrile, incident photon-to-current efficiencies were typically less than 10%. 相似文献