Photochemically active DNA-intercalating ruthenium and related complexes – insights by combining crystallography and transient spectroscopy

Abstract

Recent research on the study of the interaction of ruthenium polypyridyl compounds and defined sequence nucleic acids is reviewed.

Spectro-electrochemical Studies on [Ru(TAP)2(dppz)]2+—Insights into the Mechanism of its Photosensitized Oxidation of Oligonucleotides

“…These spectra can then be directly compared to the TA and TRIR spectra obtained for photoexcited [Ru(TAP)2(dppz)] 2+ , which when bound to guanine-containing DNA lead to photooxidation of guanine. [25][26][27][28][29][30] The yield of this photo-induced electron transfer has been shown to depend on both the enantiomer and the sequence of the DNA. 25,[27][28][29][30] One of the highest yielding system so far examined is that of the Λ-enantiomer intercalated in double-stranded d(G5C5).…”

“…[25][26][27][28][29][30] The yield of this photo-induced electron transfer has been shown to depend on both the enantiomer and the sequence of the DNA. 25,[27][28][29][30] One of the highest yielding system so far examined is that of the Λ-enantiomer intercalated in double-stranded d(G5C5). 30 The TA and TRIR spectra of this system after the electron transfer process is complete are shown in Figure 9 As noted in the Introduction, it has been reported that the excited state of [Ru(TAP)2(dppz)] 2+ is efficiently quenched by 5′-GMP and nanosecond flash photolysis showed the formation of transient species expected to be [Ru(TAP)(TAPH)(dppz)] 2+ and the guanine radical (equation 4).…”

“…[19][20][21][22][23][24][25] Photoinduced reactions sensitized by such complexes are conveniently monitored by transient visible absorption (TA) and by time-resolved infra-red (TRIR) spectroscopy. [25][26][27][28][29][30] Initial experiments, which were carried out with racemic samples and double-stranded polydGdC, demonstrated modest isotope effects for both the excited state and subsequent reverse reactions. 26 This was interpreted as a possible PCET process but in this case with the isotope effect being as a result of proton-transfer within the G-C base pair, and not to formation of [Ru(TAP)(TAPH)(dppz)] 2+ as expected for 5′-GMP.…”

X‐ray Crystal Structures Show DNA Stacking Advantage of Terminal Nitrile Substitution in Ru‐dppz Complexes

“…[28] More recently theses tructural observations have been used to interpret longstanding discussions in the literature about observations of multiple luminescence lifetimes even in apparently homogeneous Ru-DNA model systems. [29] The realisation that the typical binding mode fort hese complexes is angled intercalation prompted the investigation of the effect of asymmetrics ubstitution of the distal ring of the dppz ligand [30] (positions 10-13 in Figure 1b).…”

In-vivo evaluation of the response of Galleria mellonella larvae to novel copper(II) phenanthroline-phenazine complexes

“…However, dose limiting side effects including neurotoxicity and nephrotoxicity and the development of both acquired and inherently resistant cancers continue to be an ongoing issue in its treatment success. As such, recent research activity has focused on the rational design of metallo-agents including ruthenium [1][2][3][4][5], iron [6,7], gold [8][9][10] and copper [11][12][13][14][15][16][17][18][19] with alternative mode of action to the mono-nuclear cis-[PtX 2 (amine) 2 ] chemotype (X = leaving group, amine = neutral or carrier group) shared by cisplatin and its derivatives [20].…”