Photoinduced energy and electron transfer processes in supramolecular species, tris(bipyridine) complexes of ruthenium(II)/osmium(II), Ru(II)/Ru(III), Os(II)/Os(III), and Ru(II)/Os(III) separated by a rigid spacer

Cola, Luisa De; Balzani, Vincenzo; Barigelletti, Francesco; Flamigni, Lucia; Belser, Peter; Zelewsky, Alex von; Mathur, Sanjay; Voegtle, F.

doi:10.1021/ic00075a048

Cited by 143 publications

(84 citation statements)

References 4 publications

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“…2); the background signal in the spectrum is due to scattering. The position of the luminescence signal is characteristic of the 3 MLCT emission of the osmium tris-bipyridyl complexes [36] and confirms the coordination of three bipyridyl groups around the osmium centre.…”

Section: Luminescence Studiessupporting

confidence: 55%

Ruthenium and Osmium Podate Cyclodextrins with Dual-function Recognition Sites for Luminescent Sensing

Silva

Haider

Heck

et al. 2003

Supramolecular Chemistry

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A multifunctionalised podand cyclodextrin ligand, b-CD-(urebpy) 7 , with urea-bipyridine binding sites leads to ruthenium and osmium, {Ru[b-CD-(urebpy) 7 ]}[PF 6 ] 2 {Os[b-CD-(urebpy) 7 ]}[PF 6 ] 2 , cyclodextrins. The bipyridine ligands are preorganised by the cyclodextrin cavity encapsulating the ruthenium and osmium core to give photoactive metallocyclodextrins. The podate cyclodextrin complexes show characteristic ruthenium and osmium tri-bipyridine luminescence. It is demonstrated that the ruthenium cyclodextrins participate in sensing schemes through both the cyclodextrin cavity and the urea cage at the bottom of the cyclodextrin rim. Luminescence quenching of the ruthenium emission is observed by addition of anthraquinone guests in the cyclodextrin cavity or addition of dihydrogen phosphate anion.The development of supramolecular systems will be directed towards the design of systems that will either interact with or act as nanoscale devices in a controlled way. For example, the importance of miniature photomolecular devices in nanoscale technology has led to the design of polymetallic supramolecular assemblies. The employment of multi-electron metal centres in a single supramolecular structure provides the basis for the development of molecular energy conversion systems and molecular wires in macromolecular systems, which is a focus of our research.Zoe Pikramenou obtained her BSc from the University of Athens in Greece. She was then awarded an Academy of Athens scholarship to carry out PhD studies in the USA where she joined the group of Professor Daniel G. Nocera (currently at MIT) at Michigan State University to develop optical supramolecules as sensors for aromatic pollutants. Upon completion of the doctorate, she moved to France to join the group of Professor Jean-Marie Lehn as a Marie Curie fellow and later as a Collège de France research fellow to work on photochromic systems based on photoinduced proton transfer. She then moved to the UK to take up an appointment as a lecturer in the University of Edinburgh before she moved to her current lectureship position in the School of Chemical Sciences at the University of Birmingham. Her research interests involve the design of functional supramolecular systems with emphasis on light-activated functions including lanthanide chemistry and photophysics and cyclodextrin receptor chemistry. In the lanthanide field, the group has developed systems for lanthanides, studied controlled formation of lanthanide complexes with different sensitisers and studied the interaction with DNA. In the cyclodextrin field, energy and electron transfer via noncovalent bonds in aqueous assembled metallocyclodextrin-metalloguest systems has been demonstrated.

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Section: Luminescence Studiessupporting

confidence: 55%

Ruthenium and Osmium Podate Cyclodextrins with Dual-function Recognition Sites for Luminescent Sensing

Silva

Haider

Heck

et al. 2003

Supramolecular Chemistry

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“…For *Ru II 1 Os II , Φ D =0.014, τ D =285 ns, r =15 and 17 Å for the cis and trans conformer, respectively, and the value of the overlap integral is 4.3×10 −14 M −1 cm 3 27. The values obtained for k en from Equation (2) (3.3×10 7 and 1.5×10 7 s −1 , respectively, for the cis and trans conformer) do not fully agree with the experimental ones (2.0×10 8 and 2.2×10 7 s −1 at 298 K).…”

Section: Resultsmentioning

confidence: 99%

Photoinduced Energy‐ and Electron‐Transfer Processes in Dinuclear Ru^II–Os^II, Ru^II–Os^III, and Ru^III–Os^II Trisbipyridine Complexes Containing a Shape‐Persistent Macrocyclic Spacer

et al. 2006

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The PF6- salt of the dinuclear [(bpy)2Ru(1)Os(bpy)2]4+ complex, where 1 is a phenylacetylene macrocycle which incorporates two 2,2'-bipyridine (bpy) chelating units in opposite sites of its shape-persistent structure, was prepared. In acetonitrile solution, the Ru- and Os-based units display their characteristic absorption spectra and electrochemical properties as in the parent homodinuclear compounds. The luminescence spectrum, however, shows that the emission band of the Ru(II) unit is almost completely quenched with concomitant sensitization of the emission of the Os(II) unit. Electronic energy transfer from the Ru(II) to the Os(II) unit takes place by two distinct processes (k(en) = 2.0x10(8) and 2.2x10(7) s(-1) at 298 K). Oxidation of the Os(II) unit of [(bpy)2Ru(1)Os(bpy)2]4+ by Ce(IV) or nitric acid leads quantitatively to the [(bpy)2Ru(II)(1)Os(III)(bpy)2]5+ complex which exhibits a bpy-to-Os(III) charge-transfer band at 720 nm (epsilon(max) = 250 M(-1) cm(-1)). Light excitation of the Ru(II) unit of [(bpy)2Ru(II)(1)Os(III)(bpy)2]5+ is followed by electron transfer from the Ru(II) to the Os(III) unit (k(el,f) = 1.6x10(8) and 2.7x10(7) s(-1)), resulting in the transient formation of the [(bpy)2Ru(III)(1)Os(II)(bpy)2]5+ complex. The latter species relaxes to the [(bpy)2Ru(II)(1)Os(III)(bpy)2]5+ one by back electron transfer (k(el,b) = 9.1x10(7) and 1.2x10(7) s(-1)). The biexponential decays of the [(bpy)2*Ru(II)(1)Os(II)(bpy)2]4+, [(bpy)2*Ru(II)(1)Os(III)(bpy)2]5+, and [(bpy)2Ru(III)(1)Os(II)(bpy)2]5+ species are related to the presence of two conformers, as expected because of the steric hindrance between hydrogen atoms of the pyridine and phenyl rings. Comparison of the results obtained with those previously reported for other Ru-Os polypyridine complexes shows that the macrocyclic ligand 1 is a relatively poor conducting bridge.

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“…Photophysical properties of complex Ru–L 3 are between complex Ru–L 1 and Ru–L 2 , but electrochemical properties of complex Ru–L 3 are similar to Ru–L 2 . Electrochemical properties suggests little interaction between the three Ru II polypyridyl complexes, however, an interaction of a few reciprocal centimeters (which can not be noticed in spectroscopic and electrochemical experiments) is sufficient to cause fast intercomponent energy and energy transfer processes 18, so these complexes have potential application in the research of electron or energy transfer.…”

Section: Discussionmentioning

confidence: 99%

Synthesis, Photophysical, and Electrochemical Properties of Ru^II Polypyridyl Complexes Bridged with two Tetrapodal Symmetric and one Asymmetric Ligands

Cheng

Chen

Sun

et al. 2010

Zeitschrift anorg allge chemie

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Two symmetric tetrapodal ligands L 1-2 and one asymmetric tetrapodal ligand L 3 based on 4,5-diazafluoren have been synthesized and characterized. Ligands L 1-2 formed by the condensation of pentaerythrityl tetratosylate with 4,5-diazafluoren-9-oxime and 9-(4-hydroxy)phenylimino-4,5-diazafluorene, respectively. L 3 was prepared by two steps, 9-(4-hydroxy)phenylimino-4,5-diazafluorene reacted with pentaerythrityl tetratosylate affording 1,1',1"-tris[(4,5-diazafluoren-9-ylimino)phenoxymethyl]-1"'-(p-tosyloxymethyl)-methane, * Prof. Dr. F. Cheng Fax: +86-931-8912582 E-Mail: chengfx04@lzu.cn [a] College

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Photoinduced energy and electron transfer processes in supramolecular species, tris(bipyridine) complexes of ruthenium(II)/osmium(II), Ru(II)/Ru(III), Os(II)/Os(III), and Ru(II)/Os(III) separated by a rigid spacer

Cited by 143 publications

References 4 publications

Ruthenium and Osmium Podate Cyclodextrins with Dual-function Recognition Sites for Luminescent Sensing

Ruthenium and Osmium Podate Cyclodextrins with Dual-function Recognition Sites for Luminescent Sensing

Photoinduced Energy‐ and Electron‐Transfer Processes in Dinuclear Ru^II–Os^II, Ru^II–Os^III, and Ru^III–Os^II Trisbipyridine Complexes Containing a Shape‐Persistent Macrocyclic Spacer

Synthesis, Photophysical, and Electrochemical Properties of Ru^II Polypyridyl Complexes Bridged with two Tetrapodal Symmetric and one Asymmetric Ligands

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Photoinduced energy and electron transfer processes in supramolecular species, tris(bipyridine) complexes of ruthenium(II)/osmium(II), Ru(II)/Ru(III), Os(II)/Os(III), and Ru(II)/Os(III) separated by a rigid spacer

Cited by 143 publications

References 4 publications

Ruthenium and Osmium Podate Cyclodextrins with Dual-function Recognition Sites for Luminescent Sensing

Ruthenium and Osmium Podate Cyclodextrins with Dual-function Recognition Sites for Luminescent Sensing

Photoinduced Energy‐ and Electron‐Transfer Processes in Dinuclear RuII–OsII, RuII–OsIII, and RuIII–OsII Trisbipyridine Complexes Containing a Shape‐Persistent Macrocyclic Spacer

Synthesis, Photophysical, and Electrochemical Properties of RuII Polypyridyl Complexes Bridged with two Tetrapodal Symmetric and one Asymmetric Ligands

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Photoinduced Energy‐ and Electron‐Transfer Processes in Dinuclear Ru^II–Os^II, Ru^II–Os^III, and Ru^III–Os^II Trisbipyridine Complexes Containing a Shape‐Persistent Macrocyclic Spacer

Synthesis, Photophysical, and Electrochemical Properties of Ru^II Polypyridyl Complexes Bridged with two Tetrapodal Symmetric and one Asymmetric Ligands