Taira Imamura

Self-assembly of metallopyridylporphyrin oligomers

Abstract Various porphyrin oligomers assembled from free-base pyridylporphyrins and metallopyridylporphyrins are reviewed. In the oligomers, metal ions such as zinc, ruthenium, and osmium ions are incorporated into pyridylporphyrin units. These can act simultaneously as both axial or bridging ligands as well as functional groups. The oligomers can be divided into two groups: discrete metallopyridylporphyrin arrays and infinite networks. The latter is briefly summarized.

Reactivity of di- and tri-nuclear complexes of heavy mid-transition elements: A case of oxo-carboxylato- bridged complexes

Kinetics of the ligand substitution and oxidation reactions, pulse radiolysis, cyclic voltammetry, and function as excited-state quenchers, are discussed for the two types of complexes with the core structures, M3(p3-O)(p-RC00)6 (R = CH3, C&5; M3 = Ru3, Rh3, RhRu2) and Ru2(pL-0)(p-CH3COOh. Some important conclusions are (i) strong trans labilization by the oxide bridge, (ii) stabilization of the mixed- valence states on forming metal-&-0x0-prc molecular orbitals to give multi-step multi- electron redox behavior, and (iii) protonation at the oxide-bridge to show proton- coupled one-step two-electron transfer. Trans-labilization by the metal-metal bond is also demonstrated for some Pt-Pt, Re-Re, and Mo-Mo bonded complexes.

Synthesis and characterization of a novel dioxygen complex of molybdenum porphyrin

A new molybdenum porphyrin dioxygen complex [MoVIO(tmp)(O2)], formed by the reversible reaction of [MoIVO(tmp) with dioxygen in aprotic solvents at room temperature, is isolated and characterized by temperature-programme desorption mass, IR, 1H NMR, and UV–VIS spectroscopy.

Pyrolytic reactions of azidochromium(III) porphyrins and azidoiron(III) porphyrins in the solid state

Abstract Azidochromium(III) tetraphenylporphyrin, Cr III (tpp)N 3 (tpp = 5,10,15,20-tetraphenylporphyrinato), and azidoiron(III) tetraphenylporphyrin, Fe III (tpp)N 3 , in the solid state, were pyrolysed under 10 −5 –10 −6 torr at around 250°C, liberating nitrogen gas to afford Cr II (tpp) and Fe II (tpp) as final products, respectively. Cr V (tpp)N formed in the process of the Cr III (tpp)N 3 pyrolysis is reduced to Cr II (tpp), although pure Cr V (tpp)N prepared independently is not pyrolysed under the same conditions. In the presence of dioxygen in the toluene solutions of these pyrolysed products, Cr IV (tpp)O or [Fe(tpp)] 2 O is formed. The mechanisms of these reactions in the solid state are discussed in comparison with those in solution.

Mikroanalyse mit Hilfe von Ionenaustauschern. XXVI@@@Micro analysis with the aid of ion exchanger resins. XXVI: Nachweis geringer Mengen Kupfer(II) mit Bathocuproindisulfonar

ZusammenfassungEine neue Harztüpfelmethode mit Bathocuproindisulfonat zum spezifischen Nachweis von ng Kupfer(II) wird vorgeschlagen. Bei Anwendung eines Kügelchens weißer, weitmaschiger, stark basischer Anionenaustauscher, Diaion PA-Harze, beträgt die Erfassungsgrenze 10,4 ng Kupfer in 10μl Probelösung (1:1 · 106).SummaryA new resin spot test with bathocuproine disulfonate for the specific detection of ng amounts of copper(II) is described. Using 1 grain of white strongly basic popcorn-resin, Diaion PA 3-series, the identification limit for copper is 10.4 ng in 10μl solution (1:1 · 106).

Visible absorption spectral measurements of the formation of the cobalt porphyrin dioxygen complex using a high-pressure cell ag

Abstract The 1:1 complex formation between dioxygen and the meso -tetraphenylporphinatocobalt(II)pyridine complex in toluene was followed spectrophotometrically using a high-pressure cell. The values of the equilibrium constant K p obtained are 0.0278, 0.0513, 0.0840, 0.157 and 0.278 atm −1 at −30, −36, −42, −48 and −54dgC, respectively. The thermodynamic data are Δ H θ = −10.1±0.6 kcal mol −1 and gD S θ = −49±3 eu at a standard pressure of 1 atm.

Factors affecting the formation of alcohol and alkoxo complexes in the reactions of oxomolybdenum(V) tetraphenylporphyrin with various alcohols in dichloromethane

The addition of alcohols to dichloromethane solution of Mo(V)O(tpp)Br (tpp = meso-tetraphenylporphinato) causes three-step reactions. The products in the first, second and third stages of the reactions are solvated, alcohol and alkoxo complexes, respectively. t-Butyl alcohol does not afford the corresponding alcohol complex. The most important factor controlling the formation of alcohol complexes is the bulkiness of the alcohol molecules.