Extended X-ray Absorption Fine Structure of Copper(II) Complexes at the Air-Water Interface by a Polarized Total-Reflection X-ray Absorption Technique

Nagatani, Hirohisa; Tanida, Hajime; Watanabe, Ichiro; Sagara, Takamasa

doi:10.2116/analsci.25.475

Cited by 20 publications

(17 citation statements)

References 40 publications

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“…The fine XANES structure of the complexes in the region of the edge and above the absorption edge is primarily caused by the 1s → 4s and 1s → 4p electronic transitions along with the shake down ligand to metal transitions. The pres ence of shoulder B (8987.5 eV) caused by the splitting of the 4p sublevel [41][42][43] indicates the square coordi nation of the copper(II) ions in complex I.…”

Section: Resultsmentioning

confidence: 99%

Influence of the bridging coordination of DMSO on the exchange interaction character in the binuclear copper(II) complex with the nonsymmetrical exchange fragment

et al. 2014

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The binuclear copper(II) complex [Cu 2 L(CH 3 COO)] (I), where L 3-is the azomethine trianion based on 3 methyl 4 formyl 1 phenylpyrazol 5 one and 1,3 diaminopropan 2 ol, and its DMSO adduct (II) in which the DMSO molecule acts as an additional bridging ligand are synthesized. The structure of com plex II is determined by X ray diffraction analysis, and the structure parameters of the coordination unit of complex I are determined by EXAFS spectroscopy. The µ 2 coordination of the DMSO molecule in com pound II results in a change in the sign of the exchange interaction parameter. In complex I, the antiferro magnetic exchange interaction (2J = -169 cm -1 ) occurs between the copper(II) ions. The exchange inter action of the ferromagnetic type (2J = 174 cm -1 ) is observed in complex II. The quantum chemical calcula tions of the magnetic exchange parameters by the density functional theory method show that the role of the DMSO molecule as a switch of the exchange interaction character is exclusively the stabilization of the "bro ken" conformation of the metallocycles.

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Section: Resultsmentioning

confidence: 99%

Influence of the bridging coordination of DMSO on the exchange interaction character in the binuclear copper(II) complex with the nonsymmetrical exchange fragment

et al. 2014

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“…14 Optical spectroscopy has been performed extensively on SCC; 11,12 however, X-ray spectroscopic investigations, which render conclusions about the inner-shell electronic structure feasible are almost missing. 15 With near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, the electronic structure as well as the oxidation state can be probed. The use of soft Xray radiation allows the investigation of the K absorption edges of carbon (C), oxygen (O), and nitrogen (N), as well as the Ledges of the central metal atom, thus providing a more comprehensive analysis of the entire SCC molecule.…”

Section: ■ Introductionmentioning

confidence: 99%

On the Electronic Structure of Cu Chlorophyllin and Its Breakdown Products: A Carbon K-Edge X-ray Absorption Spectroscopy Study

Witte¹,

Mantouvalou²,

Sánchez-de-Armas

et al. 2018

J. Phys. Chem. B

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Using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, the carbon backbone of sodium copper chlorophyllin (SCC), a widely used chlorophyll derivative, and its breakdown products are analyzed to elucidate their electronic structure and physicochemical properties. Using various sample preparation methods and complementary spectroscopic methods (including UV/Vis, X-ray photoelectron spectroscopy), a comprehensive insight into the SCC breakdown process is presented. The experimental results are supported by density functional theory calculations, allowing a detailed assignment of characteristic NEXAFS features to specific C bonds. SCC can be seen as a model system for the large group of porphyrins; thus, this work provides a novel and detailed description of the electronic structure of the carbon backbone of those molecules and their breakdown products. The achieved results also promise prospective optical pump/X-ray probe investigations of dynamic processes in chlorophyll-containing photosynthetic complexes to be analyzed more precisely.

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“…Polarization-modulation infrared reflection absorption spectroscopy (PM-IRRAS) has been used to determine the molecular orientation and the conformation of layered materials formed at solid and liquid surfaces. − In PM-IRRAS, the linear polarizations of the incident light are periodically modulated, and selectivity for oriented species is drastically improved by analyzing the corresponding ac optical signals. A similar approach has also been applied to total reflection X-ray absorption fine structure (TR-XAFS) at liquid surfaces and liquid|liquid interfaces. − Polarized TR-XAFS measurements, where the linear polarization of incident X-rays is controlled by a diamond retarder crystal, allowed us to estimate the solvation structure of metalloporphyrins at interfaces in situ. − However, the application of PM-IRRAS and polarized TR-XAFS to liquid|liquid systems is rigidly limited by strong attenuation or scattering of incident beam and optical signal by solvent molecules in infrared and X-ray regions.…”

Section: Introductionmentioning

confidence: 99%

Potential-Dependent Adsorption and Orientation of meso-Substituted Porphyrins at Liquid|Liquid Interfaces Studied by Polarization-Modulation Total Internal Reflection Fluorescence Spectroscopy

et al. 2016

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Potential-dependent adsorption behavior of meso-substituted water-soluble porphyrins at the polarized water|1,2-dichloroethane (DCE) interface was studied by polarization-modulation total internal reflection fluorescence (PM-TIRF) spectroscopy. In the PM-TIRF experiments, the fluorescence signal from the interfacial region was analyzed as a function of the periodic modulation of linear-polarizations (p and s) of the incident excitation beam. The potential-dependence of PM-TIRF responses for meso-substituted porphyrins, 5,10,15,20-tetrakis(N-methylpyridyl)porphyrin (H 2 TMPyP 4+ ) and 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H 2 TPPS 4− ), indicated that both free base porphyrins were adsorbed with relatively lying orientations at the polarized water|DCE interface. The average orientation angles (θ) were estimated as θ = 61 ± 1°for H 2 TMPyP 4+ and θ = 65 ± 1°for H 2 TPPS 4− with respect to the interface normal. The wavelength-dependence of polarization-modulated fluorescence signals (PM-TIRF spectrum), which corresponds to "pure" emission spectrum of interfacial species, clearly indicated that H 2 TMPyP 4+ and H 2 TPPS 4− are adsorbed with a modification of the solvation at the interface. These results demonstrated a high ability of the PM-TIRF spectroscopy for the direct characterization of fluorescent species adsorbed at polarized liquid|liquid interfaces.

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Extended X-ray Absorption Fine Structure of Copper(II) Complexes at the Air-Water Interface by a Polarized Total-Reflection X-ray Absorption Technique

Cited by 20 publications

References 40 publications

Influence of the bridging coordination of DMSO on the exchange interaction character in the binuclear copper(II) complex with the nonsymmetrical exchange fragment

Influence of the bridging coordination of DMSO on the exchange interaction character in the binuclear copper(II) complex with the nonsymmetrical exchange fragment

On the Electronic Structure of Cu Chlorophyllin and Its Breakdown Products: A Carbon K-Edge X-ray Absorption Spectroscopy Study

Potential-Dependent Adsorption and Orientation of meso-Substituted Porphyrins at Liquid|Liquid Interfaces Studied by Polarization-Modulation Total Internal Reflection Fluorescence Spectroscopy

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