Photochem device

Polynuclear dendrimer complexes of this type can undergo redox reactions at the metal centre and have luminescent properties. They have been proposed as molecular photochemical devices, although no practical examples have yet been produced. 

Pronounced improvement of quantity and quality in the determination of antioxidizability is obtained by the photosensibilized chemiluminescence (PCL) method, realized in the Photochem device (manufacturer Analytik Jena AG, Germany). 

Bpy-type ligands (including phen, tpy and a vast range of substituted derivatives) may be assembled with a number of different metal centres to give versatile photochemical devices via the complexes as metals/complexes as ligands strategy (Scheme 11.1). If we envisage the synthesis of a mononuclear... 

TOWARDS THE DESIGN OF MOLECULAR PHOTOCHEMICAL DEVICES BASED ON RUTHENIUM BIPYRIDINE PHOTOSENSITIZER UNITS. 

Some of the possible functions of molecular photochemical devices have been classified [3] as follows ... 

In this report, we will describe some of our studies aimed at (i) obtaining new inorganic photosensitizers by second-sphere modification of known ones, and (ii) assembling photosensitizer units with other molecular components in discrete, covalently bound supramolecular structures. Studies of type (i), besides their intrinsic interest, have some relevance to the problem of how the properties of a photosensitizer are modified by inclusion in a supramolecular structure. Systems of type (ii) would be useful to study the basic processes of intramolecular electron and energy transfer involved in the performance of molecular photochemical devices. 

Bertolo, L., Tamburini, S., Vigato, P.A., etal. (2006)Tris(tropolonato)phenanthrohnelanthanide(III)complexes as photochemical devices. European Journal of Inorganic Chemistry, 2370. 

Fig. 1.1. Variation in the conversion efficiency with wavelength for photochemical devices with a threshold. Curve I is a plot of the fraction of incident solar power (in percentages) that is available at various threshold wavelength and Curve II is a plot of the thermodynamic conversion efficiencies under optimal rates of energy conversion. (Data for AM 1.2 radiation)...

Unfortunately, despite its poor luminescent properties, tpy is a desirable ligand from a structural point of view in the design of supramolecular photochemical devices. Metal bis(tpy) complexes are achiral, which means that they do not give rise to undesirable mixtures of diastereoisomers when more than one metal centre is present, and as a bridging ligand, substituted tpy compounds are easier to make into rigid linear connectors than bpy or phen derivatives. Furthermore, substituted tpy compounds do not exhibit facimer isomerism as do their bidentate counterparts (Figure 11.9). 

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