Shigeyuki Masaoka

Three supramolecular isomers, [Cu(μ4-BQ)(μ2-OAc)2]n (α phase), [Cu(μ3-BQ)(μ2-OAc)(μ3-OAc)]n (β phase), and [Cu(μ2-BQ)(μ3-OAc)2]n (γ phase), were crystallized by using the organometallic building block shown, which has two types of supramolecular synthon. Interestingly, these three supramolecular isomers were crystallized from the same solvent. BQ=benzoquinone. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2004/z53463_s.pdf or from

Abstract Experiments show that [Ru(terpy)(bpy)(OH2)]2+ is highly active as a catalyst toward oxidation of water into molecular oxygen in spite of the mononuclear character of the complex, while [Ru(terpy)(bpy)Cl]+ shows no activity at all. It is also confirmed that [Ru(terpy)(bpy)(OH2)]2+ is fairly stable under strongly oxidizing conditions in the presence of cerium(IV) ammonium nitrate, Ce(NH4)2(NO3)6, which was evidenced by spectrophotometric, mass spectrometric, and gas chromatographic analys

Visible-light-driven catalytic reduction of CO₂ is at the heart of artificial photosynthesis. Here, we demonstrate the first example of a Ru complex that can function both as a photosensitizer and catalyst for CO₂ reduction. The catalyst exhibited excellent activity for CO evolution with a high turnover number (TON, 353 for 24 h), reaction rate (TOF, 14.7 h^-1), and product selectivity (97%) under visible-light irradiation. We also succeeded in selective product f

The construction of nanostructured polynuclear metal complexes with cyclic topologies, particularly those containing multifunctional ligands containing π-electronic structures, is of great interest since they can potentially lead to compounds with unusual electrochemical properties. A novel cyclic module with a hexacarboxylate derivative is described. The results show that the peripheral substituents not only control the electronic structure, but also influence its mode of coordination.

Two new Ru(II)Pt(II) dimers, [Ru(bpy)(2)(mu-L2)PtCl(2)](2+) (5) and [Ru(bpy)(2)(mu-L3)PtCl(2)](2+) (6), were synthesized and characterized, and their electrochemical and spectroscopic properties together with their photo-hydrogen-evolving activities were evaluated (bpy = 2,2'-bypridine; L2 = 4'-[1,10]phenanthrolin-5-ylcarbamoyl)-[2,2']bipyridinyl-4-carboxylic acid ethyl ester; L3 = 4'-methyl-[2,2']bipyridinyl-4-carboxylic acid [1,10]phenanthrolin-5-ylamide). The structures of 5 and 6 are basical

The development of robust and efficient molecular catalysts based on earth-abundant transition metals for water oxidation reactions is a challenging research target. Our group recently demonstrated the high activity and stability of a pentairon-based water oxidation electrocatalyst (M. Okamura, M. Kondo, R. Kuga, Y. Kurashige, T. Yanai, S. Hayami, V. K. K. Praneeth, M. Yoshida, K. Yoneda, S. Kawata and S. Masaoka, <i>Nature</i>, 2016, <b>530</b>, 465-468). However, the development of strategies

A novel tetranuclear copper-based water oxidation catalyst was designed and synthesized by using a new multinucleating ligand containing two proton dissociation sites, 1,3-bis(6-hydroxy-2-pyridyl)-1H-pyrazole. The copper complex showed electrocatalytic activity for water oxidation reactions under aqueous basic conditions (pH 12.5) with an overpotential of approximately 500 mV. UV/Vis absorption and energy-dispersive X-ray (EDX) spectroscopic techniques coupled with electrochemical analyses of th

A Ru polypyridyl complex containing a phosphine donor promoted electrocatalytic CO2 reduction at a low overpotential. Mechanistic investigations revealed that the introduction of a phosphine donor at the trans position to the labile ligand is the key to reduce the overpotential for CO2 reduction.

Two new ruthenium(II) complexes bearing dissociable protons, [Ru(trpy)(H(2)bim)Cl]PF(6) (1) and [Ru(trpy)(H(2)bim)(OH(2))](PF(6))(2) (2) (H(2)bim = 2,2'-biimidazole and trpy = 2,2':6',2''-terpyridine), were synthesized and characterized, where the H(2)bim and M-OH(2) moieties are expected to serve as proton-dissociation sites. Single crystal X-ray diffraction analyses revealed that the H(2)bim and M-OH(2) moieties act as proton donors in intermolecular hydrogen bonds. Two pK(a) values of 2 (pK(a

This paper reports a novel crystal growth system of a coordination framework {[Cu3(CN)3{hat-(CN)3(OEt)3}]}n (1) (hat-(CN)3(OEt)3 = 2,6,10-tricyano-3,7,11-triethoxy-1,4,5,8,9,12-hexaazatriphenylene). The coordination polymer is crystallized through the reaction of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (hat-(CN)6), ethanol, and copper(I) complex, involving the breaking and forming of covalent bonds. The crystal morphologies obtained in the present system contain dumbbells, cogwh

Water oxidation is a key reaction in natural photosynthesis and in many schemes for artificial photosynthesis. Inspired by energy challenges and the emerging understanding of photosystem II, the development of artificial molecular catalysts for water oxidation has become a highly active area of research in recent years. In this Focus Review, we describe recent achievements in the development of single-site ruthenium catalysts for water oxidation with a particular focus on the overpotential of wa

Mix and shake: Lipid packaged dinuclear ruthenium(II,III) complexes of class III mixed-valence state produce a reversible hypochromic effect upon external physical stimuli, such as shaking, due to the arrangement of transition dipole moments. The effect is accompanied by tubular-to-ribbon structural changes (see scheme). Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made ava