Ru(II)-Dppz Derivatives and Their Interactions with DNA: Thirty Years and Counting

Abstract

Transition metal complexes with dppz-type ligands (dppz = dipyrido[3,2-a:2′,3′-c]phenazine) are extensively studied and attract a considerable amount of attention, becoming, from the very beginning and increasingly over time, a powerful tool for investigating the structure of the DNA helix. In particular, [Ru(bpy)2(dppz)]2+ and [Ru(phen)2(dppz)]2+ and their derivatives were extensively investigated as DNA light-switches. The purpose of this mini-review, which is not and could not be exhaustive, was to first introduce DNA and its importance at a biological level and research in the field of small molecules that are capable of interacting with it, in all its forms. A brief overview is given of the results obtained on the Ru-dppz complexes that bind to DNA. The mechanism of the light-switch active in this type of species is also briefly introduced along with its effects on structural modifications on both the dppz ligand and the ancillary ligands. Finally, a brief mention is made of biological applications and the developments obtained due to new spectroscopic techniques, both for understanding the mechanism of action and for cellular imaging applications.

Comparative studies on in vitro antitumor activities and apoptosis-inducing effects of enantiomeric ruthenium(ii) complexes

“…Furthermore, the treated cells displayed a series of nuclear morphology changes including a smaller nuclear volume, condensed chromatin and an incomplete or fragmented nucleus, which correspond to the characteristic nuclear morphology of apoptosis. 26,27 It has been known that the intercalation of an intercalator between the adjacent base-pairs of DNA results in a substantial conformation change in the regular helical structure of DNA, characterized by the despiralization of DNA and the extension of its helix, 28,29 which inhibits DNA replication either by stabilizing the cleaved DNA produced with topoisomerase II, or by preventing DNA-binding of topoisomerase I, and leads to cell death. 30,31 Generally, the DNA affinity of a drug is positively consistent with its cytotoxic potency.…”

Ruthenium(II) Polypyridyl Complexes and Their Use as Probes and Photoreactive Agents for G-quadruplexes Labelling

“…The most famous compounds triggering the interest of ruthenium(II) polypyridyl complexes as powerful tools to study DNA are the [Ru(bpy) 2 ( dppz )] 2+ and [Ru(phen) 2 ( dppz )] 2+ (dppz = dipyrido[3,2- a :2′,3′- c ]phenazine) complexes [ 188 ]. These complexes are called light-up probes as they are not luminescent in water but do emit brightly in DNA containing aqueous solutions.…”

Nitrile Substituents at the Conjugated Dipyridophenazine Moiety as Infrared Redox Markers in Electrochemically Reduced Heteroleptic Ru(II) Polypyridyl Complexes

“…Diverse types of tailored polypyridyl ligands bearing various substituents have extensively been studied for a range of applications, such as the modeling of photosystems, luminescent probes for deoxyribonucleic acid (DNA), ribonucleic acid or Gquadruplexes, etc. 1,2 Recently, spectroelectrochemical studies of the complex [Ru(tap) 2 (dppz)] 2+ (tap = 1,4,5,8-tetraazaphenanthrene, dppz = dipyrido[3,2-a:2′,3′-c]phenazine) have revealed that the singly reduced cationic species can be generated via a photoelectron transfer from guanine (G) rather than a predicted proton-coupled electron transfer (Scheme 1). The infrared (IR) spectral changes accompanying the formation of the 1e − reduced species were revealed by spectroelectrochemistry.…”