Mixed-Valency and Metal-Metal Coupling in Polynuclear Metal Complexes: Recent Progress and Prospects

Abstract

value is frequently taken as a measure for the extent of twosite interactions on molecules of interest (Eq. 1). Recent progress in the redox chemistry of multimetallic transition-metal complexes and clusters is reviewed. Special attention is paid to high-nuclearity complexes wherein redox-active sites (e.g., ferrocenyl pendants or Ru centers) are assembled in a close proximity with a well-defined geometry via the covalent or coordination bonds. A special emphasis is placed on literature survey for paddlewheel diruthenium(II,III) complexes coordinated by axial or equatorial ferrocenyl ligands, polyferrocenyl compounds in the form of wire, star, and ring, ferrocenyl-based dendrimers, and ligand-mediated molecular triangles and squares. Finally, future prospects of these mixed-valent systems are briefly discussed.

Development of Novel Photocatalyst and Cocatalyst Materials for Water Splitting under Visible Light

“…For example, WO 3 , which is unable to reduce H + , but able to produce O 2 from an aqueous solution containing appropriate electron acceptors under visible light, works as an effective building block for O 2 evolution in Z-scheme water splitting. 4,5,9 In the H 2 evolution system, the forward reactions that should occur on the photocatalyst surface are the reduction of protons by conduction band electrons and the oxidation of an electron donor (D) by valence band holes to yield the corresponding electron acceptor species (A), as follows:…”

Photocatalytic activity of LaTaON₂ powders prepared using an oxide precursor derived from a hydrothermal reaction

“…Therefore, all LaTaON 2 samples derived from LaTaO 4 synthesized by HT method exhibited only slightly aggregated morphology under all nitridation conditions. 4 . This result is due to the formation of pores on the surfaces of the particles during the nitridation process.…”

“…Therefore, it is expected that plate-like LaTaON 2 can be obtained by the nitridation of plate-like LaTaO 4 oxide precursor synthesized by HT method. LaTaON 2 prepared from plate-like LaTaO 4 precursor with large surface area is predicted to have improved photocatalytic activity.…”

“…However, industrial H 2 production currently releases CO 2 because of its use of natural gas, which is a fossil fuel. In contrast, water splitting by photocatalyst has attracted attention because of its potential for producing H 2 using water andsunlight [1][2][3][4]. Domen et al reported that the development of a photocatalyst that absorbs visible light of a wavelength longer than 600 nm is required for the practical application of photocatalytic water splitting [3,5].…”

“…In addition, we compared their photocatalytic activity for H 2 evolution from an aqueous methanol solution under visible light irradiation. 4 LaTaO 4 oxide precursors were prepared by the HT method and SSR method with flux. The procedure employed for the HT method was based on a previously reported [16,17] .5%]) for 30 min.…”