Synthesis and Excited-State Properties of a Novel Ruthenium Nucleoside:  5-[Ru(bpy)₂(4-m-4‘-pa-bpy)]²⁺-2‘-deoxyuridine

Abstract

The synthesis and photophysical properties of a novel ruthenium-modified nucleoside are reported. The key synthetic step to 5-[Ru(bpy)2(4-m-4‘-pa-bpy)]2+-2‘-deoxyuridine involves the Pd(0)-catalyzed cross-coupling of a propargylamine-derivatized Ru(bpy)3 2+ and 3‘,5‘-dibenzoyloxy-2‘-deoxy-5-iodouridine. The long-lived 3MLCT excited state (1300 ns) of 5-[Ru(bpy)2(4-m-4‘-pa-bpy)]2+-2‘-deoxyuridine has an emission maximum centered at 640 nm. Step-scan Fourier transform infrared (S2FTIR) time-resolved spectroscopy reveals the excited-state electron to be localized on the modified bipyridine with the excited-state dipole oriented toward the 2‘-deoxyuridine.

Site‐Specific Control of N7–Metal Coordination in DNA by a Fluorescent Purine Derivative

“…In this approach, electroactive and/or luminescent metal complexes are introduced into DNA through intercalating agents, [24,25] covalent end labels, [26,27] or C5-modified pyrimidine residues. [28][29][30] Metallo-nucleobase derivatives of purines are much less studied, with only a few reported examples of ferrocene, Ru II , and Os II complexes of C7-and C8-modified purines. [31][32][33] Due to biaryl-related fluorescence phenomena, [34] arylation of the 8 position of purines can provide highly emissive nucleobase derivatives [34][35][36][37][38][39][40][41][42][43] with the ability to mediate proper base-pairing interactions along both Watson-Crick and Hoogsteen faces.…”

Solid-Phase Synthesis and Photophysical Properties of DNA Labeled at the Nucleobase with Ru(bpy)2(4-m-4‘-pa-bpy)2+

“…37 We selected this particular 5-[Ru(bpy) 2 (4-m-4′-pa-bpy)] 2+ -2′-deoxyuridine nucleoside since the excited state was known to be long-lived and localized on the bipyridine attached to the uridine. 39 This phosphoramidite approach is suited for synthesizing metallo-labeled oligonucleotides; however, it often requires the synthesis of large molecular weight nucleoside derivatives containing complex functional groups that are time-consuming to prepare and difficult to purify and handle. Thus, there is a need for alternative methods of labeling oligonucleotides at site-specific locations with transition metal complexes that can serve as synthetic nucleases, cross-linking agents, or spectroscopic probes.…”

DNA modified with metal complexes: Applications in the construction of higher order metal–DNA nanostructures

“…They can be tagged as a phosphoramidite derivative to the DNA backbone [22], as a base modification [23], or as a deoxyribose modification [24] to obtain different luminescent properties. Ru complexes have also been attached to DNA using post-modification methods, as reported by the Barton and Mesmaeker groups [25].…”