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.

Research in the field of supramolecular chemistry has rapidly grown in recent years due to the generation of fascinating structural topologies and their associated physical properties. In order to rationally synthesize such high-dimensionality systems, several different classes of non-covalent intermolecular interactions in the crystal engineering toolbox can be utilized. Among these, attractive metallophilic interactions, such as those observed for d10 gold(I), have been increasingly harnessed as a design element to synthesize functional high-dimensional systems. This tutorial review will explore the methods by which gold(I) and other d10 and d8 metal centres have been employed to increase structural dimensionality via the formation of metal-metal interactions. Physical and optical properties associated with metallophilicity-based supramolecular structures will also be highlighted.

Three water-soluble cobalt porphyrins have been investigated as water oxidation catalysts via photo-initiation using Ru(II)(bpy)3(2+)/Na2S2O8. The pH dependence of the turnover frequency revealed maximum activity at pH 11. Based on the second order dependence on catalyst concentration for the rate of water oxidation, we suggest a bimolecular radical coupling process as the rate determining step.

The performance of a water-soluble cobalt porphyrin ([{meso-tetra­(4-sulfonatophenyl)­porphyrinato}­cobalt­(III)], CoTPPS) as a catalyst for the photoreduction of CO2 in fully aqueous media has been investigated under visible light irradiation using [Ru­(bpy)3]2+ as a photosensitizer and ascorbate as a sacrificial electron donor. CO is selectively produced (>82%) with high efficiency (926 TONCO; TONCO = turnover number for CO). Upon optimization, selectivities of at least 91% are achieved. Efficiencies up to 4000 TONCO and 2400 h–1 TOFCO (TOFCO = turnover frequency for CO) are reached at low catalyst loadings, albeit with loss in selectivity. This work successfully demonstrates the ability of CoTPPS to perform highly efficient photoreduction of CO2 in water while retaining its high selectivity for CO formation.