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Polymer nanofibers with controlled diameters were formed by continuous spinning using ordered anodic porous alumina as a spinneret. The diameter of the polymer nanofibers could be controlled by cha...

Heat-treatment of nano-boehmite intercalated with monoethanolamine derivatives (NBM-MEA) affects its photoluminescence properties. The photoluminescence band of NBM-MEA undergoes a red-shift with an increase in temperature. On the basis of IR and ESR spectroscopic behavior and analysis of time-resolved photoluminescence decay, it is concluded that the emission band originates from the F+ center as singly ionized oxygen vacancies in the boehmite structure and from carbon impurities due to decomposition of monoethanolamine derivatives.

A blue photoluminescent nano boehmite was prepared by a solvothermal reaction of aluminum hydroxide gel in monoethanolamine (MEA) at a low temperature of 120 °C for 6 h; it shows a photoluminescence emission at 420 nm with excitation of 360 nm that is attributed to the formation of the carbamate derivative of MEA.

Porous Si particles were prepared by the barrel anode etching of small Si particles. The depth of the holes formed on the surface of the Si particles could be controlled by changing the anode etching time. The process reported here allows high-throughput preparation of small porous Si particles with controlled geometrical surface structures. The obtained porous Si particles can be applied in various types of functional devices.

We report the synthesis and luminescent properties of halide-bridged tricopper(I) complexes with a polyaza cryptand having three 2,6-bis(aminomethyl)pyridyl spacers. The asymmetric {Cu3X3} structur...

A Co(III) complex possessing selective nitric oxide (NO) capturing ability was immobilized onto a bulky phosphonium type ionic liquid-modified Au electrode, IL/Au, (Co@IL/Au), which was confirmed b...

The role of the amide carbonyl oxygens in the nitrile hydratase (NHase) active site for the nitrile coordination to the metal center was studied using a distorted square-pyramidal N2S3-type Co(III)...

We investigated anodization of gold in aquaous solutions of carboxylic acids as a continuation of anodization of gold in oxalic acid. In contrast to the anodization in aquaous oxalic acid, in which...

Artificial siderophore–Fe3+ complexes were prepared and modified with Au nanoparticles. These nanoparticles were found to selectively adsorb onto microbes and initiate selective aggregation. The ag...

The unique active site structure of nitrile hydratase (NHase) has a central metal ion (CoIII or FeIII) coordinated by two amide nitrogens from the peptide backbone, one cysteine sulfur and two oxid...

Three new complexes with FeIII2(μ-O)(μ-OH) core surrounded with one, two, and three amino groups, that is, (6-amino-2-pyridylmethyl)bis(pyridylmethyl)amine (MAPA), bis(6-amino-2-pyridylmethyl)(pyri...

Ruthenium(II) complexes, [Ru(babp)(dmso)L], consisting of tetradentate square-planar ligand (babp = 6,6′-bis(benzoylamino)-2,2′-bipyridinato) and two monodentate axial ones, DMSO and L (L = dmso or...

In order to understand the effect of an oxygen-containing ligand on the physico-chemical properties and reactivities of hydrogenperoxocopper complexes, new copper(II) complexes with the N3O-type tr...

Monodisperse hydrogel particles were prepared by membrane emulsification using ordered anodic porous alumina. The size of the obtained hydrogel particles could be controlled by changing the pore si...

Novel ruthenium(II) polypyridyl complexes with diethynylphenanthrolines containing acetylthiophenyl unit(s) have been prepared and characterized by photophysical measurements. These complexes showe...

The bis-N,N-carboxymethy-(S)-phenylalaninato carbonato cobalt(III) complex, [Co(bcmpa)(CO3)]2−, has been prepared as a simple model that enables the recognition of an amino acid (Haa) whose coordination behaviours in solution have been characterized by electronic absorption (AB), circular dichroism (CD) and 1H NMR spectroscopies. The reaction of the K2[Co(bcmpa)(CO3)] complex with amino acids (Haa) has predominantly afforded the [Co(bcmpa)(aa)] complex in the trans(N)-configuration mode, rather than in the cis(N)-form. By using amino acid derivatives with bulky substituents at their amino or carboxylate sites under a neutral condition, the reactions have been demonstrated to be initiated by coordination of the amino nitrogen site. Interestingly, the cis(N)-complex, which is isolated as a minor product, isomerizes to the trans(N)-form in the presence of active charcoal under pH 7 in an aqueous solution. The site-selective coordination of Haa to the [Co(bcmpa)(CO3)]2− complex and the stereoselective isomeri...

A novel Ni(II) complex with an asymmetric monoamino–monoamidato–dithioether square-planar coordination (1) was prepared as a model compound of the active center of NiSOD and characterized by spectr...

The existence of a CH-π interaction has clearly been demonstrated by use of the ternary metal (Cu(II), Pd(II)) complexes involving o-/m-/p-methyl substituted L-phenylalanine (L-o-mPhe, L-m-mPhe, L-p-mPhe) and 1,10-phenanthroline (phen) on the basis of 1H NMR, electronic absorption, and CD spectroscopies, and X-ray diffraction method. The crystal structure of [{Cu(p-mPhe)(phen)}2{Cu(phen)2}(μ3-CO3)](ClO4)2 has revealed a marked structural feature suggesting CH-π and/or π–π interactions, although [Cu(L-o-mPhe)(phen)(H2O)]ClO4 does not show any interaction. CD spectra in the d–d region for [Cu(L-o-mPhe)(phen)]ClO4, [Cu(L-m-mPhe)(phen)]ClO4, and [Cu(L-p-mPhe)(phen)]ClO4 in aqueous solution have exhibited an obvious negative Cotton effect, and the magnitudes have significantly been reduced in dioxane/water in the order: [Cu(L-p-mPhe)(phen)]ClO4 ≤ [Cu(L-m-mPhe)(phen)]ClO4 < [Cu(L-o-mPhe)(phen)]ClO4. 1H NMR spectra of [Pd(L-o-mPhe)(phen)]ClO4, [Pd(L-m-mPhe)(phen)]ClO4, and [Pd(L-p-mPhe)(phen)]ClO4 have exhibited...

Redox reactions between horse heart cytochrome c and optically active Ru complexes were kinetically studied. The kinetic parameters for the oxidation of ferrocytochrome c with Ru III complexes indicated an apparent enantioselectivity, which clearly shows that exact molecular recognition is achieved through non-polar interactions rather than electrostatic ones.

Mononuclear copper complexes with a tripodal tetradentate ligand, tris(6-pivaloylamino-2-pyridylmethyl)amine (Htppa), and several anions have been prepared as a model metal centre of copper enzymes, whose structures have been examined by electronic absorption, ESR and NMR spectral, cyclic voltammetry, and X-ray diffraction methods. Those with an anion such as OH−, Cl−, Br−, and I− were shown to form a trigonal-bipyramidal geometry. The X-ray structures of [Cu(Htppa)](ClO4)2·2H2O·CH3OH, [CuCl(Htppa)]ClO4, [Cu(OH)(Htppa)]ClO4, [Cu(OH)(tppa)], and [Cu(tppa)](BPh4), obtained as a single crystal, revealed all trigonal-bipyramidal geometry with four nitrogen atoms of Htppa in trigonal plane and axial position and with the anion in another apical position. The reaction with NaN3 gave [Cu(N3)2(Htppa)], whose crystal structure was a square-pyramid with three nitrogen atoms of Htppa and N3− in square-planar positions and with another N3− in apical position. The redox potentials of [CuCl(Htppa)]ClO4 in MeCN or CH2Cl...

Cytochrome c553 and cytochrome b were isolated from soluble and membrane fractions of Alcaligenes xylosoxidans GIFU 1051, respectively, and their spectroscopic characterizations have been performed. Cytochrome c553 has been shown to be in the low spin state both in the oxidized and reduced forms at room temperature by the absorption and magnetic circular dichroism (MCD) spectra, while the high spin heme has been also observed in the cryogenic electron paramagnetic resonance (EPR) spectra. Exogenous small ligands such as NO and CO bind to cytochrome c553 by expelling the axial His ligand. The membrane-bound cytochrome b has two heme b centers in a protein molecule which are the active centers of NO reductase, the cytochrome bc complex, although the enzyme activity was rather low. The absorption, MCD, and EPR spectra of the membrane-bound cytochrome b showed that two heme b centers are in the different electronic states, the high and low spin states. Cytochrome c553 is the natural electron donor to the memb...

The crystal structures of trans-[Co(acac)2(PMePh2)2]PF6 (acac = 2,4-pentanedionate ion) (1), trans-[Co(acac)2(H2O)(PMePh2)]ClO4 (2), and trans(P,P)-[Co(acac)(CN)2(PMePh2)2] (3) were determined by the X-ray diffraction method. Complex 1 crystallizes in the monoclinic, space group P2/n, with two molecules in a unit cell of dimensions a = 17.151(2), b = 10.347(2), c = 10.996(2) A, β = 107.84(1)°, V = 1857.6(6) A3. Complex 2 crystallizes in the monoclinic, space group P21/c, with four molecules in a unit cell of dimensions a = 10.161(3), b = 17.291(5), c = 14.938(3) A, β = 91.76(2)°, V = 2623(1) A3. Complex 3 crystallizes in the monoclinic, space group C2/c, with four molecules in a unit cell of dimensions a = 21.628(1), b = 8.974(1), c = 16.203(1) A, β = 106.396(2)°, V = 3012.9(1) A3. The Co–P bond length for complex 1, 2.329(1) A, is significantly longer than those for complexes 2 (2.213(1) A) and 3 (2.2698(4) A). These lengths are discussed with the hydrolytic properties.

The single crystal of cis-β-Λ-S,S-[Co(CO3)(trien)](ClO4)·H2O (trien = triethylenetetramine) has spontaneously resolved from the aqueous solution of cis-α-[CoCl(NH3)(trien)](ClO4)2 containing hydrogencarbonate anion, whose crystal structure has been determined by X-ray diffraction method. The complex crystallizes in the monoclinic space group P21 with a = 7.410(1), b = 12.354(3), c = 8.676(1) A, β = 108.88(1)°, and Z = 2. The final R and Rw values for the 3056 observed reflections with Io > 3σ(Io) are 0.045 and 0.055, respectively. The tetradentate ligand, trien, is linked to the cobalt atom in cis-β-configuration, and the carbonato anion is coordinated to the metal atom as a didentate ligand. The Co–N bond lengths are 1.904(6), 1.928(4), 1.941(4), and 1.955(5) A, and the two Co–O bond lengths are both 1.909(4). The absolute configuration of the complex cation can be designated as Λ(λλδ) and those about two secondary nitrogen atoms are both S.

The reaction of salicylidene-L-alanine with the Co(III) complex involving 2,2′:6′,2″-terpyridine (terpy) in aqueous ethanol solution afforded a peculiar transamination to form the complex, [Co(α-hydroxy salicylidene-o-hydroxybenzylamine)(terpy)]+, whose structure has been confirmed by X-ray structure analysis and positive FAB mass spectrometry.

The bis-(N-pyridoxy-L-phenylalaninato)cobalt(III) complex exhibiting an anomalous assembly of aromatic rings around the pyridoxy 2′-methyl group has been synthesized and characterized by 1H-NMR spectroscopy and X-ray analysis. The 1H-NMR spectrum of the complex in D2O, methanol-d4 and dimethylsulfoxide-d6 revealed peculiar upfield shift in 2′-methyl group. The detailed examination of the crystal structure demonstrated that the two C–H bond vectors of 2′-methyl group were directed toward the planes of the pyridoxy pyridine and phenylalanyl benzene rings, respectively. These findings indicate the induced assembly of aromatic rings through a CH···π interaction.

Structural and spectroscopic studies have been performed on the ternary Cu(II) complexes containing 4-halophenylalanines (XPhe) (X = I or Br) and 2,2′-bipyridine (bpy). The absorption spectra of the 1 : 1 : 1 Cu(bpy)(XPhe) systems exhibited a single d–d peak at 605—608 nm (pH 6—7), and the band centered at ca. 320 nm due to the charge transfer interaction between the substituted phenyl ring and bpy was observed in the difference spectra in the near ultraviolet region. Three complexes with XPhe, [Cu(bpy)(DL-IPhe)(NO3)] (1), [Cu(bpy)(DL-BrPhe)(NO3)] (2), and [Cu(bpy)(L-IPhe)]ClO4 (3) were isolated as crystals, and the structures were determined by the X-ray diffraction method. Complex 1 crystallizes in the monoclinic space group, P21/n, with four molecules in a unit cell of dimensions a = 5.292(1), b = 27.315(8), c = 13.848(2) A, β = 90.05(2)°. Complex 2 also crystallizes in the monoclinic space group, P21/n, with four molecules in a unit cell of dimensions a = 5.293(5), b = 27.18(1), c = 13.540(6) A, β = 9...

Full geometry optimizations have been carried out for the complex formations of Cu+ and Cu(2,2′-bipyridine)+ with CO2 by using the density functional methods. The calculation demonstrated that the end-on coordination mode was mainly favored for all cases, while the binding of 2,2′-bipyridine (bpy) to Cu(CO2)+ largely labilized the end-on coordination mode and stabilized the in-plane side-on coordination mode. The detailed examination of the population analysis indicate that the coordination of bpy to Cu+ weakens the electron donating character of CO2 to Cu+ and promotes the important participation of π-back-donative interaction from the metal ion to CO2.

The structures and the formation energies of [MCl4]2− (M = Cr, Mn, Fe, Co, Ni, Zn) have been examined by the density functional method. The optimized structures of [MnCl4]2−, [CoCl4]2− and [ZnCl4]2− are a regular tetrahedron with the M–Cl distances of 236, 227, and 231 pm, respectively. The structures of [CrCl4]2− and [FeCl4]2− are a flattened tetrahedron with the M–Cl distances of 236 and 231 pm, respectively, and with the flattening angles of 156 and 112°, respectively, while that of [NiCl4]2− is a tetrahedron elongated along an S4 axis with the Ni–Cl distance of 226 pm and the corresponding angle of 97°. The formation energies of [MCl4]2− have been compared with their experimental data, and the relative energies of the transformation from [M(H2O)6]2+ to [MCl4]2− are also evaluated in connection with the stability of the anions in aqueous solutions.

Transformation of amino acid to α-hydroxy amino acid has been discovered in the Co(III) complex with pyridoxylidene-amino acid ligand, which has been discussed on the basis of the 1H-NMR and FAB mass spectroscopic data and X-ray crystallographic analysis.

The intrinsic structures of [CuCl4]2− and [CuBr4]2− have been investigated by ab initio density functional method and determined to be D2d symmetry with the flattening X-Cu-X angles of 138° and 130° for the case of X = Cl and Br, respectively, and the Cu-X distances of 228 pm and 241 pm, respectively, which are good agreement with the experimental data.

With a view to understanding the factors affecting the chemical properties of the copper sites in proteins, model copper(II) complexes of two multidentate ligands with nitrogen and sulfur atoms, 1,5-bis(2-pyridylmethylamino)-3-thiapentane (pmtp) and 2,6-bis(2,6-dithiaheptyl)pyridine (dthp), have been isolated as [Cu(pmtp)][Cu(pmtp)ClO4](ClO4)3 (1) and [Cu(dthp)(NO3)2] (2), respectively, and studied by X-ray diffraction, spectroscopic, and electrochemical methods. Complex 1 crystallizes in space group P21/a of the monoclinic system with four [Cu(pmtp)]2+ ions and four [Cu(pmtp)(ClO4)]+ ions in a cell of dimensions a = 24.180(7), b = 31.855(7), c = 9.760(3) A, and β = 143.84(1)°. The coordinations around the coppers in the two independent complexes are square-pyramidal and octahedral, respectively, with an amine nitrogen, two pyridine nitrogens, and a thioether sulfur at the equatorial positions (eq) and an amine nitrogen (and a perchlorate oxygen in addition in the octahedral complex) at the axial position...

A thin metal Ag film was obtained at an air/solution interface by using a spread stearic acid layer as a supporting substrate of electroless plating. The properties of the film and the condition of the electroless plating of Ag was examined with scanning electron microscopy and in situ reflectance spectroscopy.

The bis(diphenylphosphino)methane(dppm) compounds of copper(I), [Cu2(μ-dppm)2(biL)2](PF6)2 (biL=1,10-phenanthroline and its derivatives), have been synthesized and characterized by 1H and 31P NMR spectroscopy and X-ray crystallography. The molecules are found to contain a [Cu2(dppm)2]2+ framework with the two copper atoms bridged by two dppm ligands to give eight-membered C2P4C2 rings. This framework shows a staggered conformation subject to the coordination of additional ligands, biL. The coordination 1H and 31P shifts of the dppm are well-correlated with the basicity of the nitrogen donor atom of biL, sensitive to variations in the copper-ligand binding as well as their metal-to-ligand charge-transfer band. Crystallographic data of [Cu2(dppm)2(phen)2] are as follows, monoclinic space group P21⁄c, a=11.515(2) A, b=27.922(4) A, c=12.493(2) A, β=107.68(1)°, U=3827(1) A3, and Z=2.

Transformation among cobalt(II) dichloride hydrates in aqueous solutions was studied by the optical microscopic method. Although there are three hydrates (CoCl2·6H2O, CoCl2·4H2O, and CoCl2·2H2O) in the phase equilibrium diagram, the only solution mediated transformation between CoCl2·6H2O and CoCl2·2H2O could be observed under the present experimental conditions and it was confirmed that CoCl2·4H2O hardly formed compared with the other two hydrates. In order to investigate the reason why CoCl2·4H2O was hardly crystallized at the transformation from CoCl2·6H2O through CoCl2·2H2O and vice versa, the crystal structure of CoCl2·4H2O was investigated by the X-ray diffraction method. The structure of CoCl2·6H2O was reexamined because previously reported results had a relatively large R-factor. The crystal of CoCl2·4H2O is monoclinic, space group P21/a with a=11.548(1) A, b=9.342(1) A, c=6.056(1) A, β=110.79(1)°, and Z=4. The complex has a slightly distorted octahedral geometry about Co2+ ion and two Cl− ions ar...

[Pt(S2CNEt2)2] reacts with [AgClO4] to form [{Pt3(S2CNEt2)6Ag2}(ClO4)2]. Its crystal has an extended two-dimensional cationic lattice with an Ag-Pt-Ag arrangement [Pt-Ag = 2.932(2) A and ∠Ag–Pt–Ag = 166.8(1)°] unsupported by covalently bridging ligands.

Gold nanoparticles (AuNPs) have been arranged on a nanotemplate prepared on indium tin oxide substrate. This template, consisting of circular areas of about 200 nm in diameter hexagonally assembled...

The fabrication of nanocomposites consisting of uniform-sized metal nanoparticles arranged at uniform intervals in a fibrous polymer matrix is described. The combined process of metal deposition in...

Uniform-sized polymer nanofibers were fabricated by the extrusive spinning of a photocurable monomer under UV irradiation using ordered anodic porous alumina as a nozzle for the spinning. The size ...

The anodization of purple gold (AuAl2) in oxalic acid at low voltage (5 V) generated uniformly sized Au nanoparticles on the substrate. The surface of the sample showed a characteristic color after...

Ordered pillar array structures of TiO2 were prepared by nanoimprinting process using ordered anodic porous alumina as a mold. The shape of the obtained pillars of TiO2 corresponded to that of the ...

A new ruthenium dye with an electron donating triarylamine ligand, J8, has been synthesized as a highly efficient sensitizer for a dye-sensitized solar cell, giving an overall conversion efficiency...

New tetrakis(2-pyridonato)copper(II)–palladium(II)/platinum(II) complexes, [CuPd(2-pyrd)4(py)] (1), [CuPt(2-pyrd)4(py)] (2), [CuPd(2-pyrd)4(H2O)] (3), and [CuPt(2-pyrd)4(H2O)] (4) (2-pyrd = 2-pyrid...

We show surface-enhanced Raman scattering (SERS) on an ordered array of Au nanodots prepared from a highly ordered anodic porous alumina mask. The intensity of SERS signals is strongly dependent on the height of the Au dots, indicating the existence of optimum geometrical structures for SERS. The fabrication process of the nanodot array described in the present study enables easy preparation of SERS substrates.

A CoIII complex with a novel N2S2-type ligand, asymmetrically arranged with 6-5-5 chelate ring, was prepared as an active site model of nitrile hydratase and was found to show a higher stability co...

Reaction of hydroxozinc(II) complex bearing amino group with CO2 gave carbamate product, whose generation and reaction mechanism have been studied structurally and spectroscopically as a structural...

Antireflection (AR) polymer structures composed of tapered conical pillars were fabricated using highly ordered anodic porous alumina. The shape of the holes in the anodic porous alumina was contro...

A novel iron complex with a distorted coordination geometry, [FeII((−)-sp)(OBz)2] (1) ((−)-sp = (−)-sparteine, OBz = benzoate anion), was prepared and structurally characterized by X-ray analysis. ...

The Ru complex, [RuII(babp)(dmso)2] (1) (H2babp = 6,6′-bis(benzoylamino)-2,2′-bipyridine), was immobilized into mesoporous silicate FSM-16. The heterogeneous catalyst demonstrated a more selective ...

Two types of azurins (azurins-1 and -2), derived from Alcaligenes xylosoxidans GIFU 1051, were first discriminated electrochemically using Au electrode modified with the optically active CoIII comp...