Molecular Light Switches for DNA

Auffrant, A. Barbieri, F. Barigelletti, J. Lacour, P. Mobian, J. P. Collin, J. P. Sauvage and B. Ventura, Inorg. Chem. 2007, 46, 6911. 

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Friedman AE, Chambron JC, Sauvage J-P, Turro NJ, Barton JK (1990) Molecular light switch for DNA Ru(bipy)2(dppz). J Am Chem Soc 112 4960... 

The data concerning [Ru(phen)2 (dppz)] + nicely illustrate the concept of molecular light switch (dppz for 28). When the complex is bound to DNA, the excited-state lifetime is approximately 200 ns, whereas without bounding, it is only 200 ps. This light-switch effect provides the basis for a valuable photophysical probe of nucleic acids. Luminescent characteristics of the complexes bound to DNA can also be used to illustrate the chiral discrimination associated with binding to the right-handed helix. Direct oxidation of... 

A keen recent interest in polyimine ruthenium(II) complexes (tris-bipyridinates, tris-phenanthrolinates, and their analogues) has largely been evoked by the ample scope they offer as selective DNA-cleaving agents and probes in biochemistry. Such ruthenium(II) complexes, as well as their photophysics, are of particular interest in creating the devices for molecular electronics (e.g., systems of the light-switch type) and in analytical detection of metal ions as well. 

Understandably, there is an enormous richness in the photophysical and photochemical behavior of the excited states present in diimine rhenium tricarbonyl complexes. Indeed, this plethora of molecular photophysical characteristics has led to a wide range of interesting and important applications, including their use as catalysts [21-25], sensors [26-33], probes for photo-polymerization [10, 34, 35], optical switches [36 15], light-emitting materials [46-52], nonlinear optical materials [53-56], binding or photocleavage of DNA [57-61], and radiopharmaceuticals [62-66], Under the purview of this article our focus will be to cover photophysical and photochemical properties and hence other aspects, such as synthetic, catalytic, pharmaceutical, etc., will not be discussed. 

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