Takuzo Funabiki

An Iron(III)–Monoamidate Complex Catalyst for Selective Hydroxylation of Alkane CH Bonds with Hydrogen Peroxide

Selective oxidation: the success of the title reaction is caused by the strong electron donation from the amidate moiety of the dpaq ligand to the iron center (dpaq=2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate). This process facilitates the O-O bond heterolysis of the intermediate Fe(III)OOH species to generate a selective oxidant without forming highly reactive hydroxyl radicals.

Optical oxygen-sensing properties of porphyrin derivatives anchored on ordered porous aluminium oxide plates

An optical oxygen-sensing activity of anchored porphyrin derivatives on ordered porous aluminium oxide plates was studied in relevance to development of new oxygen-sensing systems. Porphyrin derivatives, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrin, 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrin, 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrin, and their platinum complexes, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrinatoplatinum(II), 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrinatoplatinum(II), 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrinatoplatinum(II), were synthesized and anchored by an equilibrium adsorption method on aluminium oxide plates, which were prepared by an anodic oxidation. The excitation spectra of the porphyrin-anchored layers showed a broadened and blue-shifted Soret band compared with the corresponding porphyrins in DMSO. The luminescence intensity decreased with increasing oxygen concentrations. The oxygen-sensing ability estimated from I(0)/I(100) (I(0) and I(100) denote the luminescence intensity in 0 and 100% oxygen) was 9.08, 6.78, 8.71, 81.9, 35.5, and 39.1, which are greater than those of corresponding porphyrin derivatives in DMSO under the measured conditions, and indicates the remarkable enhancement effect of platinum(II). Non-linear Stern-Volmer plots were well fitted by the two component system to give the oxygen-sensitive constant (K(SV1)/%(-1)), the oxygen-insensitive constant (K(SV2)/%(-1)), and the former contribution (f(1)): 0.232, 3.32 x 10(-2), and 0.642; 0.141, 2.05 x 10(-2), and 0.687; 0.143, 1.05 x 10(-2), and 0.882; 17.3, 7.04 x 10(-3), and 0.980; 10.2, 1.43 x 10(-2), and 0.935; 16.3, 8.35 x 10(-3), and 0.954. The response time for the change of the atmospheric gas from argon to oxygen was 9.4 s, 12.5 s, 9.6 s, 5.0 s, 8.9 s, and 4.6 s, indicating the shortening effect of platinum. The reverse effect of platinum was observed in the change from oxygen to argon: 15.5 s, 17.0 s, 20.8 s, 667.4 s, 590.1 s, and 580.4 s, indicating the specific interaction of oxygen to the platinum(II) center.

Poly[[{μ3-tris­[2-(4-phenyl-1,2,3-triazol-1-yl)eth­yl]amine}silver(I)] hexa­fluorido­phosphate]

The title compound, {[Ag(L)]PF6)n {L is tris[2-(4-phenyl-1,2,3-triazol-1-yl)ethyl]amine, C30H30N10}, consists of alternating two-dimensional cationic layers of [Ag(L)]+ and anionic PF6 − layers. Each AgI atom is three coordinated in a T-shaped geometry by three N atoms from three ligands. Each ligand links three AgI atoms, generating a two-dimensional network structure with two different metallacycles, A and B. In A, eight coordination units from four ligands connect four AgI atoms, forming a 48-membered ring. In B, four coordination units from two ligands link two AgI atoms, forming a 24-membered ring. Each B ring is surrounded by four A rings, and each A ring has four A and four B rings as neighbours. This cationic layer thus generates a 4.82 topology network, with each AgI centre and ligand acting as a three-connected topological node.

Tuning of spin crossover equilibrium in catecholatoiron(III) complexes by supporting ligands.

Introduction of electron-withdrawing groups on co-ligands effectively raises the spin crossover temperature of catecholatoiron(III) complexes and induces a significant amount of the low spin species in solution even at around room temperature.