A stereochemical study of polyhedral eight-vertex structures is presented, based on continuous shape measures (CShM). Reference polyhedra, shape maps, and minimal-distortion interconversion paths are presented for eight-vertex polyhedral and polygonal structures within the CShM framework. The application of these stereochemical tools is analyzed for several families of experimental structures: 1) coordination polyhedra of molecular transition-metal coordination compounds, classified by electron configuration and ligands; 2) edge-bonded polyhedra, including cubane structures, realgar, and metal clusters; 3) octanuclear transition-metal supramolecular architectures; and 4) coordination polyhedra in extended structures in inorganic solids. Structural classification is shown to be greatly facilitated by these tools, and the detection of less common structures, such as the gyrobifastigium, is straightforward.

The Rich Stereochemistry of Eight‐Vertex Polyhedra: A Continuous Shape Measures Study

Catalysis is a key enabling technology for solar fuel generation. A number of catalytic systems, either molecular/homogeneous or solid/heterogeneous, have been developed during the last few decades for both the reductive and oxidative multi-electron reactions required for fuel production from water or CO2 as renewable raw materials. While allowing for a fine tuning of the catalytic properties through ligand design, molecular approaches are frequently criticized because of the inherent fragility of the resulting catalysts, when exposed to extreme redox potentials. In a number of cases, it has been clearly established that the true catalytic species is heterogeneous in nature, arising from the transformation of the initial molecular species, which should rather be considered as a pre-catalyst. Whether such a situation is general or not is a matter of debate in the community. In this review, covering water oxidation and reduction catalysts, involving noble and non-noble metal ions, we limit our discussion to the cases in which this issue has been directly and properly addressed as well as those requiring more confirmation. The methodologies proposed for discriminating homogeneous and heterogeneous catalysis are inspired in part by those previously discussed by Finke in the case of homogeneous hydrogenation reaction in organometallic chemistry [J. A. Widegren and R. G. Finke, J. Mol. Catal. A, 2003, 198, 317–341].

Solar fuels generation and molecular systems: is it homogeneous or heterogeneous catalysis?

A photo-hydrogen-evolving molecular device made up of a tris(2,2'-bipyridine)ruthenium(II) derivative and a dichloro(2,2'-bipyridine)platinum(II) derivative has been found to serve as the first effective model of a "molecular device" which evolves molecular hydrogen from water in the presence of a sacrificial electron donor (EDTA), under the visible-light illumination.

A photo-hydrogen-evolving molecular device driving visible-light-induced EDTA-reduction of water into molecular hydrogen.

Metal-mediated and metal-catalyzed hydrolysis of nitriles

Recent work towards the production of hydrogen via reduction of protons is described. Most of the systems examined in this perspective use a molecular chromophore for harvesting visible light, a catalyst, which is reduced by the excited (or reduced) chromophore, and finally a sacrificial electron source to oxidatively or reductively quench the chromophore. The reduced catalyst is then responsible for the reduction of protons resulting in hydrogen evolution. Relevant mechanistic work on this topic is also discussed.

Molecular systems for light driven hydrogen production

Publisher Summary This chapter discusses structures and reactivities of platinum-blues and the related amidate-bridged platinumIII. Compounds platinumIII is usually unstable and can be isolated only in complexes with certain special ligands. Monomeric PtIII complex is very rare and so far only one well-characterized complex is known, in contrast to the now increasing knowledge of PtIII dinuclear complexes. The chapter mentions amidate-bridged dinuclear PtIII complexes and multinuclear PtII,III mixed-valent complexes, generally called “platinumblues.” The novel zigzag chain structures of the platinum blues having Pt-Pt bonds, redox chemistry between PtII and PtIII in these complexes electron spin resonance (ESR) spectra of Pt III, 195Pt-NMR of PtIII, and various stoichiometric and catalytic reactions with organic molecules mostly involving PtII/III redox reactions are summarized in the chapter. The antitumor inactive compounds are relatively stable and are disrupted only to dinuclear amidate-bridged compounds. The advantage of these complexes is that each Pt complex is isolated in pure form, and their crystal structure is known.

Structures and Reactivities of Platinum-Blues and the Related Amidate-Bridged Platinumiii Compounds

The first mixed-valent octanuclear platinum blue compounds with bridging acetamidate and 2-fluoroacetamidate ligands, [(H 3 N) 2 Pt(CH 3 CONH) 2 Pt(NH 3 ) 2 ] 4 (NO 3 ) 10 .4H 2 O and [(H 3 N) 2 Pt(CH 2 FCONH) 2 Pt(NH 3 ) 2 ] 4 (NO 3 ) 8.66 .4H 2 O, are crystallographically characterized.

Syntheses, Crystal Structures, and Electronic, ESR, and x-ray Photoelectron Spectra of Acetamidate-and 2-Fluoroacetamidate-Bridged Mixed-Valent Octanuclear Platinum Blues

Kazuko Matsumoto

Papers

Structures and Reactivities of Platinum-Blues and the Related Amidate-Bridged Platinumiii Compounds

Syntheses, Crystal Structures, and Electronic, ESR, and x-ray Photoelectron Spectra of Acetamidate-and 2-Fluoroacetamidate-Bridged Mixed-Valent Octanuclear Platinum Blues

Mixed-valent octanuclear platinum acetamide complex, [Pt8(NH3)16(C2H4NO)8]10+

Homogeneous catalyses of mixed-valent octanuclear platinum complexes in photochemical hydrogen production from water

Homogeneous catalysis of platinum blue related complexes in photoreduction of water into hydrogen