- Facile and efficient syntheses of 2,2'-bipyridine-based bis(phosphonic) acids
-
The synthesis and characterization of new 2,2'-bipyridine ligands bearing two phosphonic acid groups either on the (4,4'), (5,5') or (6,6') positions are described.
- Penicaud, Virginie,Odobel, Fabrice,Bujoli, Bruno
-
-
Read Online
- A Phosphonate Substituent in a 1,10-Phenanthroline Ligand Boosts Light-Driven Catalytic Water Oxidation Performance Sensitized by Ruthenium Chromophores
-
A series of new Ruthenium(II) complexes based on the (1,10-phenanthrolin-5-yl)diethyl phosphonate ligand L2 and their corresponding phosphonic acid along with reference compounds are synthesized in order to evaluate the influence of the phosphonate substitution on the catalytic performance of such molecules. UV-vis absorption and emission spectroscopy show, that introduction of a phosphonate moiety into the periphery of the phenanthroline ligand does not alter the photophysical properties of the complex. In contrast, the electrochemical features of all compounds are affected upon respective functionalization compared to the reference molecule [Ru(bpy)3](PF6)2 in aqueous medium. Photostability tests in water or in water/persulfate show a dependency of the stability towards photodecomposition on quenching efficiency with persulfate anion. The lower quenching efficiency thus leads to increased stability based on the negative charge of the phosphonate moiety in 2 and P1 in aqueous medium following a quenching efficiency trend of [Ru(bpy)3](PF6)2>1>2>P1. Photocatalytic water oxidation using [Ru(dpp)(pic)2](PF6)2 reveals that compound 1 and [Ru(bpy)3](PF6)2 doe not exhibit any activity under the utilized conditions, P1 shows a negligible TON of 7, whereas compound 2 reaches a TON of 140 after 1 h. This fact highlights that the redox potential is not the sole driver in the catalytic cycle and accentuates the importance of different criteria determining the suitability of photosensitizers in light-driven water oxidation, such as light absorption, redox potential of the RuIII/RuII event, photostability towards and quenching efficiency with the sacrificial agent.
- Amthor, Sebastian,Keil, Philip,Nauroozi, Djawed,Perleth, Daniel,Rau, Sven
-
p. 4790 - 4798
(2021/11/30)
-
- Directly Coupled Versus Spectator Linkers on Diimine PtII Acetylides—Change the Structure, Keep the Function?
-
Modification of light-harvesting units with anchoring groups for surface attachment often compromises light-harnessing properties. Herein, a series of [donor–acceptor–anchor] platinum(II) diimine (bis-)acetylides was developed in order to systematically compare the effect of conjugated versus electronically decoupled modes of attachment of protected anchoring groups on the photophysical properties of light-harvesting units. The first examples of “decoupled” phosphonate diimine PtII complexes are reported, and their properties are compared and contrasted to those of carboxylate analogues studied by a diversity of methods. Ultrafast time-resolved IR and transient absorption spectroscopy revealed that all complexes have a charge-transfer (CT) lowest excited state with lifetimes between 2 and 14 ns. Vibrational signatures and dynamics of CT states were identified; the assignment of electronic states and their vibrational origin was aided by TDDFT calculations. Ultrafast energy redistribution accompanied by structural changes was directly captured in the CT states. A significant difference between the structures of the electronic ground and CT excited states, as well as differences in the structural reorganisation in the complexes bearing directly attached or electronically decoupled anchoring groups, was discovered. This work demonstrates that decoupling of the anchoring group from the light-harvesting core by a saturated spacer is an easy approach to combine surface attachment with high reduction potential and ten times longer lifetime of the CT excited state of the light-absorbing unit, and retain electron-transfer photoreactivity essential for light-harvesting applications.
- Archer, Stuart A.,Keane, Theo,Delor, Milan,Bevon, Elizabeth,Auty, Alexander J.,Chekulaev, Dimitri,Sazanovich, Igor V.,Towrie, Michael,Meijer, Anthony J. H. M.,Weinstein, Julia A.
-
p. 18239 - 18251
(2017/12/07)
-
- Phosphonic acid anchored ruthenium complexes for ZnO-based dye-sensitized solar cells
-
We report on the development of ruthenium dyes for the application in flexible ZnO based dye-sensitized solar cells. The ZnO based solar cells were prepared by electrodeposition using eosin Y as a structure-directing agent. The newly synthesized ruthenium dyes differed in the complexity of the extended π-donor-system and in their anchor moieties. As alternatives to carboxylic acids as anchor groups, dyes carrying phosphonic acids were studied. Comparison of the dyes contrary to what could be expected showed that the phosphonic acid anchored dyes were not superior to the carboxylic anchored dyes. A surprising second effect was that the dyes with the least sophisticated ligands performed best. Exploring possible reasons we established a simple model that allows pre-evaluation of the applicability of the dyes before testing them in real solar cells.
- Neuthe, Katja,Bittner, Florian,Stiemke, Frank,Ziem, Benjamin,Du, Juan,Zellner, Monika,Wark, Michael,Schubert, Thomas,Haag, Rainer
-
-
- Synthesis of phosphonic acid derivatized bipyridine ligands and their ruthenium complexes
-
Water-stable, surface-bound chromophores, catalysts, and assemblies are an essential element in dye-sensitized photoelectrosynthesis cells for the generation of solar fuels by water splitting and CO2 reduction to CO, other oxygenates, or hydrocarbons. Phosphonic acid derivatives provide a basis for stable chemical binding on metal oxide surfaces. We report here the efficient synthesis of 4,4′-bis(diethylphosphonomethyl)-2,2′- bipyridine and 4,4′-bis(diethylphosphonate)-2,2′-bipyridine, as well as the mono-, bis-, and tris-substituted ruthenium complexes, [Ru(bpy) 2(Pbpy)]2+, [Ru(bpy)(Pbpy)2]2+, [Ru(Pbpy)3]2+, [Ru(bpy)2(CPbpy)]2+, [Ru(bpy)(CPbpy)2]2+, and [Ru(CPbpy)3] 2+ [bpy = 2,2′-bipyridine; Pbpy = 4,4′-bis(phosphonic acid)-2,2′-bipyridine; CPbpy = 4,4′-bis(methylphosphonic acid)-2,2′-bipyridine].
- Norris, Michael R.,Concepcion, Javier J.,Glasson, Christopher R. K.,Fang, Zhen,Lapides, Alexander M.,Ashford, Dennis L.,Templeton, Joseph L.,Meyer, Thomas J.
-
p. 12492 - 12501
(2013/11/19)
-
