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Sei Tsuboyama

Bio: Sei Tsuboyama is an academic researcher. The author has contributed to research in topics: X-ray photoelectron spectroscopy & Copper. The author has an hindex of 2, co-authored 2 publications receiving 130 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the properties of Cu(II) complexes of saturated macrocyclic ligands with square-pyramidal array were examined by cyclic voltammetry, electron spin resonance, visible absoption and magnetic circular dichroism spectroscopy.

123 citations

Journal ArticleDOI
TL;DR: In this paper, the copper 2p X-ray photoelectron spectra of cupric complexes were measured and the intensity of the shake-up satellite relative to the main line was also measured.
Abstract: The copper 2p X-ray photoelectron spectra (XPS) of cupric complexes, the structures of which have been well characterized, were measured. The intensity of the so-called "shake-up" satellite relative to the main line was also measured. It was found that the satellite intensity decreased as the cupric complex became covalent. It was also found using this satellite intensity that a cupric complex of (S)-3-aminohexahydroazepine (abbreviated as S-ahaz), [Cu(S-ahaz)2](BF4)2, is directly coordinated by an F atom.

13 citations


Cited by
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Journal ArticleDOI
TL;DR: Structural and thermodynamic features of the binding interactions of DNA with bleomycin, its metal complexes, and adducts of metallobleomycins are reviewed, and the DNA cleavage reaction involving iron-bleomycin is examined.

128 citations

Journal ArticleDOI
TL;DR: In this article, the development of the coordination chemistry of N-alkylated cyclam ligands from its inception in 1973 with the first report of tetramethylcyclam was examined.

100 citations

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TL;DR: The known redox potentials of selected Cu 2+ /Cu + couples complexed with N-, S- and O-donor ligands are empirically correlated with various characteristics of the ligands as mentioned in this paper.

83 citations

Journal ArticleDOI
TL;DR: In this paper, the formation and stability of the metal complexes in the cavities of the zeolite were investigated by several spectroscopic, thermal analysis, sorption and microscopic techniques.
Abstract: Nickel(II) and copper(II) complexes of the Schiff base ligand O,O′-trimethyl bis (salicylidene isonicotinylhydrazone) (H2L) were synthesized and characterized. The encapsulation of these complexes in the cavities of the zeolite was achieved by a fixed ligand method (FLM). The free complexes (FC) and the retention of the zeolite encapsulated metal complexes [ZEMC; i.e., Ni(II)L–Y, Cu(II)L–Y] were investigated by several spectroscopic, thermal analysis, sorption and microscopic techniques [i.e., FTIR, NMR, ESI-mass, conductivity, DRS/UV-Vis, EPR, XPS, AAS, TGA, XRD, nitrogen isotherm, magnetic and (SEM/TEM)EDX]. This study reveals the formation and stability of the metal complexes in the cavities of the zeolite. The catalytic activities of free complexes and encapsulated complexes were studied in the liquid phase oxidation of benzhydrol/H2O2 and the photodegradation of rhodamine-B (RhB) under UV/visible (H2O2) irradiation. The catalytic activities of benzhydrol (BH) oxidation and RhB degradation were higher with free complexes and encapsulated complexes, respectively. In most cases, the copper(II) [Cu(II)L·2ClO4, Cu(II)L–Y] complexes showed better activity than the nickel(II) complexes [Ni(II)L·2ClO4, Ni(II)L–Y] in both BH and RhB degradation reactions. The enhancement of Cu(II)L–Y activity was mainly due to the metal present in the cavities and on the surface. Hence, in the case of FC, rate of the reaction (% of conversion) for the copper(II) complexes is more than that for nickel(II) in BH oxidation, but, in the case of ZEMC, the photocatalytic activity and rate of reaction (% of conversion) were more for Cu(II)L–Y than Ni(II)L–Y. These results show that both the oxidation reactions follow pseudo first order kinetics. The catalytic activities of the recovered and purified ZEMC were compared with the fresh catalyst.

81 citations

Journal ArticleDOI
TL;DR: In this paper, the electrochemical and spectral properties of three copper(II) complexes were investigated by cyclic voltammetry, electronic and ESR spectra, and the results from spectroscopic and redox studies were consistent with the crystallographic results and perfectly related to each other.
Abstract: The electrochemical and spectral behaviors of three copper(II) complexes [CuL1] 1, [CuL2] 2 and [CuL3] 3, where L1, L2 and L3 are the dianions of macrocyclic oxamido Schiff bases, have been investigated by cyclic voltammetry, electronic and ESR spectra. These macrocyclic complexes, which incorporate both oxamido and imine groups, can undergo quasi-reversible reduction (CuII → CuI) and oxidation (CuII → CuIII). The crystal structures of 1 and 2 have been determined by single-crystal X-ray analysis. The difference in ring size leads to significant differences in molecular and crystal structure, electronic and ESR spectra and redox behavior. In the [14]N4 macrocyclic complex, 2, the CuN4 chromophore assumes a nearly square-planar co-ordination geometry, but the geometry in the [15]N4 macrocyclic complex, 1, is distorted towards tetrahedral. The results from spectroscopic and redox studies are consistent with the crystallographic results and perfectly related to each other. The main factors that determine the relative stability of CuI and CuIII in these complexes are the size, geometry and flexibility of the co-ordination cavity.

81 citations