Rhenium polypyridine complexes

Lo and co-workers reported the synthesis and characterisation of rhenium polypyridine isothiocyanate [Rc(N N)(CO)3(py-3-NCS)]+ (10) [40] and maleimide [Re(N"N)(CO)3(py-3-mal)]+ (11) [41] complexes. Photoexcitation of all the complexes results in intense and long-lived 3MLCT (dir(Re) -> tc (N N)) emission under ambient conditions. A universal M13 reverse sequencing primer modified with an aminohexyl group at the 5 -... 

Luminescent ruthenium(II) polypyridine indole complexes such as [Ru (bpy)2(bpy-indole)]2+ (37) and their indole-free counterparts have been synthesised and characterised [77]. The ruthenium(II) indole complexes display typical MLCT (djt(Ru) tt (N N)) absorption bands, and intense and long-lived orange-red 3MLCT (djt(Ru) -> Ti (bpy-indolc)) luminescence upon visible-light irradiation in fluid solutions at 298 K and in alcohol glass at 77 K. In contrast to the rhenium(I) indole complexes, the indole moiety does not quench the emission of the ruthenium(II) polypyridine complexes because the excited complexes are not sufficiently oxidising to initiate electron-transfer reactions. Emission titrations show that the luminescence intensities of the ruthenium(II) indole complexes are only increased by ca. 1.38- to... 

In the following sections, luminescent organometallic rhenium(I) and iridium(III) polypyridine complexes relying on the labelling or binding strategies mentioned above will be described. We focus on the molecular structures, spectroscopic and photophysical properties of the complexes, and the emissive behaviour and potential applications of the labelled bioconjugates. 

Despite the rich emission properties of rhenium(I) polypyridine complexes being well documented, reports on the interactions of related complexes with DNA are limited compared to the ruthenium(II) analogues. The DNA-binding properties of... 

The first class of luminescent biotinylation reagents, derived from rhenium(I) polypyridine complexes [Re(NAN)(CO)3(py-biotin-NCS)]+ (24), have been reported by Lo and co-workers [62], To investigate the amine-specific reactivity... 

The emission properties of rhenium(I) polypyridine complexes have been utilized in biological studies. Activation of the coordinated isonicotinic acid of the complex [Re(CO)3 (2,9-Mc2-4,7-Ph2-phen)(py-4-COOH)]+... 

Time-resolved, step-scan FT-IR spectroscopy has been used to monitor the v(CO) frequencies of rhenium(I) carbonyl polypyridine complexes and hence to study the excited-state electronic structures of these systems. The MLCT and IT character in the emissive states of [Re(CO)3(phen)(py-4-Me)]+ and [Re(CO)3(dppz)(PPh3)]+, respectively, has been studied by this technique. The presence of two close-lying states of MLCT and IL character for the complex [Re(CO)3(4,4 - NH2 2-bpy)(py-4-Et)]+ was also confirmed. 

Several types of transition metal complexes have been used as photocatalysts for C02 reduction,63,67 but the ones most studied are ruthenium (II) and rhenium (I) complexes with polypyridine ligands. Thus, Ru(bpy)32+ can be both photosensitizer and catalyst or another metal complex may serve as catalyst. Alternatively, Re(bpy)(CO)3X-type complexes may serve as... 

The two sulfydryl-targeting rhenium(l) polypyridine complexes 28 and 29 were also recently synthesized and conjugated to cysteine-containing proteins. 

In the previous chapter (07AHC(93)185), complexes of polypyridine ligands with non-transition and early transition metals were considered. Most publications, however, are dedicated to the rhenium(I) and ruthenium(II) complexes, and the number of sources is so high that they deserve separate chapters. Moreover, studies of such complexes become more and more popular due to their unique photochemical and electrochemical properties and ability to form molecular assemblies and nanocrystallites. Herein we consider organomanganese and organorhenium complexes of polypyridine ligands. As always in this series of chapters, emphasis will be on the synthetic and coordination aspects, as well as reactivity. We have attempted to document all the publications on applied aspects, but without analyzing them since this could be the subject of a separate chapter. 

Luminescent organometallic complexes used for cell imaging can be divided in two main families, namely (i) carbonyl complexes, most commonly octahedral rhenium c-tricarbonyl derivatives incorporating a polypyridine ligand and (ii) cyclometalated complexes such as iridium and platinum derivatives containing the ubiquitous 2-phenylpyridine unit (complexes 1-3 in Scheme 11.2). 

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