Efficient Energy Transfer in Supramolecular, Hydrogen‐Bonded Polypyridylruthenium‐Osmium Complexes

Rau, Sven; Schäfer, Bernhard; Schebesta, Sebastian; Grüßing, André; Poppitz, Wolfgang; Walther, Dirk; Duati, Marco; Browne, Wesley R.; Vos, Johannes G.

doi:10.1002/ejic.200390193

Cited by 32 publications

(13 citation statements)

References 14 publications

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“…Earlier Beauchamp and co‐workers had shown that rhenium(III) complexes with biimidazole ligands not only bind halide anions via hydrogen bonds but also form hydrogen bond networks with benzoate anions . Energy transfer processes between metal complexes as well as organic triplet emitters and metal complexes have also been observed for hydrogen bonded systems which consisted of the biimidazole‐carboxylate motive . We were able to show that DNB quenches the phosphorescence of 12 by about 50 % in a 1:1 mixture in chloroform, and further addition of up to 8 equivalents leads to a residual luminescence of only about 8 % with respect to the pristine complex.…”

Section: Sensors For Small Anionssupporting

confidence: 52%

Optical Sensing of Anions via Supramolecular Recognition with Biimidazole Complexes

Rommel

Sorsche

Fleischmann

et al. 2017

Chemistry A European J

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Phosphorescent metal complexes with peripheral N-H donor functionalities have attracted great attention as potential molecular sensing units for anionic species lately. In this contribution we discuss the development and potential of anion recognition and sensing features of recent examples of luminescent 2,2'-biimidazole complexes of ruthenium(II), iridium(III), osmium(II) and cobalt(III). The general dependency of photophysical features in these complexes regarding the acid-base chemistry of the peripheral N-H functionalities will be outlined as a basic requirement for optical ion recognition. Systematic strategies for the tuning and specific improvement by synthetic means will be discussed regarding recent reports. With respect to their distinct photophysical features, different transition metals are considered individually to demonstrate particular trends regarding ligand modification within the respective groups. In summary, this review elucidates the current state-of-the-art and future potential of the versatile class of 2,2'-biimidazole based sensor chromophores.

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Section: Sensors For Small Anionssupporting

confidence: 52%

Optical Sensing of Anions via Supramolecular Recognition with Biimidazole Complexes

Rommel

Sorsche

Fleischmann

et al. 2017

Chemistry A European J

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“…The discontinuities at 1 equiv. preclude determination of the association constant ( K a ) for the biimidazole–carboxylate interaction, but prior studies have revealed K a values of the order of 10 5 –10 6 M –1 for this type of salt bridge 9a,10. The fact that there is a discontinuity for all four signals in Figure 2 strongly suggests that the type of cation–anion interaction changes fundamentally when more than 1 equiv.…”

Section: Resultsmentioning

confidence: 98%

“…This includes, for example, hydrogen‐bonded cation–anion adducts between amidinium cations and carboxylates that mimic the naturally occurring salt bridges mentioned above 6. Cationic metal complexes of 2,2′‐biimidazole (biimH 2 ) and 2,2′‐bibenzimidazole (bibzimH 2 ) have been reported to form hydrogen‐bonded pairs with carboxylates7 as well as other anions,8 and this has opened the possibility for investigations of photoinduced charge9 and energy transfer10 within such adducts.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular and Intramolecular Energy Transfer with Ruthenium–Anthracene Donor–Acceptor Couples: Salt Bridge versus Covalent Bond

Freys

Wenger

2010

Eur J Inorg Chem

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The formation of hydrogen‐bonded cation–anion adducts between the complex [Ru(bpy)2(biimH2)]2+ (bpy = 2,2′‐bipyridine; biimH2 = 2,2′‐biimidazole) and anthracene‐9‐carboxylate in dichloromethane solution was investigated by 1H NMR, optical absorption, and luminescence spectroscopy. The experimental data indicates that more than one anthracene‐9‐carboxylate anion can interact closely with the dicationic ruthenium complex. Energy transfer from the photoexcited ruthenium complex to anthracene‐9‐carboxylate in 1:1 adducts of these two components was investigated by transient absorption spectroscopy and compared to intramolecular energy transfer in a covalently linked ruthenium‐xylene‐anthracene dyad with a comparable donor–acceptor distance.

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“…24). 52 Although, the system studied is very sensitive to hydrogen bond disruptors (e.g. water), in dry aprotic solvents efficient energy transfer could be observed using a combination of luminescence and single photon counting techniques.…”

Section: 47mentioning

confidence: 99%

Elucidating Excited State Electronic Structure and Intercomponent Interactions in Multicomponent and Supramolecular Systems

et al. 2005

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Rational design of supramolecular systems for application in photonic devices requires a clear understanding of both the mechanism of energy and electron transfer processes and how these processes can be manipulated. Central to achieving these goals is a detailed picture of their electronic structure and of the interaction between the constituent components. We review several approaches that have been taken towards gaining such understanding, with particular focus on the physical techniques employed. In the discussion, case studies are introduced to illustrate the key issues under consideration. IntroductionMolecular devices, based on supramolecular (multicomponent) assemblies employing covalent and non-covalent bonds between components, are of increasing interest in the development of molecular electronics and photonic devices. One of the primary goals behind the construction of supramolecular systems is to control the direction and rate of electron and energy transfer processes, both energetically and spatially. Although the energetic characteristics of these systems can be manipulated relatively easily, spatial control, in terms of both direction and rate, of energy and electron transfer can be achieved only when the orbital nature of both ground and excited electronic states is understood. Multinuclear transition metal complexes, such as those based on d 6 polypyridyl complexes (i.e., Re(I), Ru(II), Os(II) Rh(III), Ir(III)) have received considerable attention, both in fundamental studies and for application in molecular photonics. 2 The attraction of these metal compounds arises from the well-defined electrochemical and photophysical properties of their polypyridyl complexes and the extensive synthetic chemistry available, which enables systematic tuning of these properties for particular applications. 3 An additional advantage of employing 2nd and 3rd row transition metal complexes in studying intercomponent interactions lies in the stability of these complexes in different redox states. In consequence, the present tutorial review focuses primarily on metal-centred systems. However, it must be emphasised that the techniques discussed and approaches taken in these studies are not exclusive to metal based systems but can be applied equally well to organic systems. Han Vos, where he used density functional theory to study the electronic structures and Raman spectra of ruthenium complexes. After completing his PhD in 2004, he was appointed as a postdoctoral researcher in the group of P r o f . C i a r a n R e g a n i n University College Dublin. His current research interests involve the application of computational techniques to systems of biological interest.

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Efficient Energy Transfer in Supramolecular, Hydrogen‐Bonded Polypyridylruthenium‐Osmium Complexes

Abstract: Hydrogen bond association between ruthenium bibenzimidazole and carboxylated polypyridylosmium complexes results in stable supramolecular aggregates. The determined stability constant of logK ഠ 6 ± 0.3 allows efficient energy transfer from the ruthenium to the osmium moiety.

Cited by 32 publications

References 14 publications

Optical Sensing of Anions via Supramolecular Recognition with Biimidazole Complexes

Optical Sensing of Anions via Supramolecular Recognition with Biimidazole Complexes

Supramolecular and Intramolecular Energy Transfer with Ruthenium–Anthracene Donor–Acceptor Couples: Salt Bridge versus Covalent Bond

Elucidating Excited State Electronic Structure and Intercomponent Interactions in Multicomponent and Supramolecular Systems

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