Molecular light switch for DNA : Ru(bpy)2(dppz)2+
06 Jun 1990-Journal of the American Chemical Society (American Chemical Society)-Vol. 112, Iss: 12, pp 4960-4962
TL;DR: In this article, a transition-metal complex was used as a molecular light switch for double-helical DNA, which showed no photoluminescence in aqueous solution at ambient temperatures.
Abstract: Considerable research has focused on the development of nonradioactive probes for nucleic acids. Extensive photophysical studies indicate that Ru(phen){sub 3}{sup 2+} bound to double-helical DNA displays an increase in luminescence owing to intercalation; emission from the metal-to-ligand charge transfer (MLCT) excited state decays as a biexponential with one lifetime of 2 {mu}s attributed to the intercalative form and a second lifetime of 0.6 {mu}s (indistinguishable from the free species) assigned to the surface bound form. Here we report the application of a novel transition-metal complex as a true molecular light switch for DNA. This probe is Ru(bpy){sub 2}(dppz){sup 2+} (bpy = 2,2{prime}-bipyridine, dppz = dipyrido(3,2-a:2{prime},3{prime}-c)phenazine), which shows no photoluminescence in aqueous solution at ambient temperatures, but displays intense photoluminescence in the presence of double-helical DNA, to which the complex binds avidly.
Citations
More filters
TL;DR: A more complete understanding of how to target DNA sites with specificity will lead not only to novel chemotherapeutics but also to a greatly expanded ability for chemists to probe DNA and to develop highly sensitive diagnostic agents.
Abstract: The design of small complexes that bind and react at specific sequences of DNA becomes important as we begin to delineate, on a molecular level, how genetic information is expressed. A more complete understanding of how to target DNA sites with specificity will lead not only to novel chemotherapeutics but also to a greatly expanded ability for chemists to probe DNA and to develop highly sensitive diagnostic agents.
1,769 citations
TL;DR: The stacked aromatic heterocycles of the DNA duplex therefore serve as an efficient medium for coupling electron donors and acceptors over very long distances.
Abstract: Rapid photoinduced electron transfer is demonstrated over a distance of greater than 40 angstroms between metallointercalators that are tethered to the 5' termini of a 15-base pair DNA duplex. An oligomeric assembly was synthesized in which the donor is Ru(phen)2dppz2+ (phen, phenanthroline, and dppz, dipyridophenazine) and the acceptor is Rh(phi)2phen3+ (phi, phenanthrenequinone diimine). These metal complexes are intercalated either one or two base steps in from the helix termini. Although the ruthenium-modified oligonucleotide hybridized to an unmodified complement luminesces intensely, the ruthenium-modified oligomer hybridized to the rhodium-modified oligomer shows no detectable luminescence. Time-resolved studies point to a lower limit of 10(9) per second for the quenching rate. No quenching was observed upon metallation of two complementary octamers by Ru(phen)3(2+) and Rh(phen)3(3+) under conditions where the phen complexes do not intercalate. The stacked aromatic heterocycles of the DNA duplex therefore serve as an efficient medium for coupling electron donors and acceptors over very long distances.
910 citations
907 citations
TL;DR: This critical review presents the active and/or emerging areas of ECL research as well as new applications and phenomena of ECR, such as light-emitting electrochemical cell, wireless electrochemical microarray, and single molecule detection.
Abstract: Electrochemiluminescence (ECL) is chemiluminescence triggered by electrochemical techniques. More than 150 ECL assays with remarkably high sensitivity and extremely wide dynamic range are currently available, and accounts for hundreds of millions of dollars in sales per year. The recent development of ECL is particularly rapid. After a brief introduction to ECL, this critical review presents the active and/or emerging areas of ECL research as well as new applications and phenomena of ECL, such as light-emitting electrochemical cell, wireless electrochemical microarray using ECL as photonic reporter, high throughput analysis, aptasensors, immunoassays and DNA analysis, ECL of nanoclusters and carbon nanomaterials, ECL imaging techniques, scanning ECL microscopy, colorimetric ECL sensor, surface plasmon-coupled ECL, electrostatic chemiluminescence, soliton-like ECL waves, ECL investigation of molecular interaction, and single molecule detection. Finally, some perspectives on this rapidly developing field are discussed (322 references).
901 citations
TL;DR: In this paper, the photochemical properties of Ru(II) polypyridine complexes are discussed and an overview of various research topics involving ruthenium photochemistry which have emerged in the last 15 years are discussed.
Abstract: Ruthenium compounds, particularly Ru(II) polypyridine complexes, are the class of transition metal complexes which has been most deeply investigated from a photochemical viewpoint. The reason for such great interest stems from a unique combination of chemical stability, redox properties, excited-state reactivity, luminescence emission, and excited-state lifetime. Ruthenium polypyridine complexes are indeed good visible light absorbers, feature relatively intense and long-lived luminescence, and can undergo reversible redox processes in both the ground and excited states. This chapter presents some general concepts on the photochemical properties of Ru(II) polypyridine complexes and gives an overview of various research topics involving ruthenium photochemistry which have emerged in the last 15 years. In particular, aspects connected to supramolecular photochemistry and photophysics are discussed, such as multicomponent systems for light harvesting and photoinduced charge separation, systems for photoinduced multielectron/hole storage, and photocatalytic processes based on supramolecular Ru(II) polypyridine species. Interaction with biological systems and dye-sensitized photoelectrochemical cells are also briefly discussed.
751 citations