15862-18-7Relevant articles and documents
Synthesis of new bis-BINOLs linked by a 2,2e′-bipyridine bridge
Bai, Xiao-Li,Liu, Xu-Dong,Wang, Mang,Kang, Chuan-Qing,Gao, Lian-Xun
, p. 458 - 464 (2005)
A series of new C2-symmetric chiral ligands 8, 9, 11 and 12, consisting of two binaphthyl units linked by a 2,2′-bipyridine bridge, has been synthesized via Suzuki cross-coupling reactions.
Photoinduced Electron Transfer Coupled to Donor Deprotonation and Acceptor Protonation in a Molecular Triad Mimicking Photosystem II
Pannwitz, Andrea,Wenger, Oliver S.
, p. 13308 - 13311 (2017)
The first artificial donor-sensitizer-acceptor compound in which photoinduced long-range electron transfer is coupled to donor deprotonation and acceptor protonation is reported. The long-lived photoproduct stores energy in the form of a radical pair state in which the charges of the donor and the acceptor remain unchanged, much in contrast to previously investigated systems that exhibit charge-separated states comprised of electron-hole pairs. This finding is relevant for light-driven accumulation of redox equivalents, because it exemplifies how the buildup of charge can be avoided yet light energy can be stored. Proton-coupled electron transfer (PCET) reactions at a phenol donor and a monoquat acceptor triggered by excitation of a Ru(II) sensitizer enable this form of photochemical energy storage. Our triad emulates photosystem II more closely than previously investigated systems, because tyrosine Z is oxidized and deprotonated, whereas plastoquinone B is reduced and protonated.
A straightforward synthesis of 5-bromo and 5,5'-dibromo-2,2'-bipyridines
Romero,Ziessel
, p. 6471 - 6474 (1995)
We herein report on the selective synthesis of 5-bromo-2,2'-bipyridine 2 and 5,5'-dibromo-2,2'-bipyridine 3 by direct bromination of 2,2'-bipyridine hydrobromide salt 1, as well as by radical decarboxylative bromination of the corresponding acid chlorides.
A Bipyridine-Based Conjugated Microporous Polymer for the Ir-Catalyzed Dehydrogenation of Formic Acid
Broicher, Cornelia,Foit, Severin R.,Rose, Marcus,Hausoul, Peter J.C.,Palkovits, Regina
, p. 8413 - 8419 (2017)
Formic acid is considered a promising energy storage medium, and its selective dehydrogenation enables the generation of high-purity H2. Herein we report a bipyridine-based conjugated microporous polymer (CMP) loaded with [Cp?IrCl2]2 for the base-free aqueous dehydrogenation of formic acid to H2/CO2. This catalyst exhibits high activity and selectivity at temperatures over 130 °C and with formic acid concentrations as high as 10 M. Recycling tests demonstrate a low Ir leaching and a gradual increase in the activity over six runs and a low CO content in the gas phase of about 138 ppm. TOFs of up to 123894 h-1 were obtained using 0.1 wt % Ir loading.
Cyclometalated iridium(III) complexes as photosensitizers for long-range electron transfer: Occurrence of a coulomb barrier
Hanss, David,Freys, Jonathan C.,Bernardinelli, Gerald,Wenger, Oliver S.
, p. 4850 - 4859 (2009)
Six cyclometalated iridium(III) complexes were investigated to assess their potential as photosensitizers for long-range electron transfer, and two of them were incorporated directly into covalent donor-bridge-acceptor molecules. The influence of ligarid substitutions on the excited-state properties and the photoredox behavior of the iridium complexes was explored by optical absorption, steady-state and time-resolved luminescence spectroscopy, as well as by electrochemical methods. Bimolecular electron transfer between the photoexcited complexes and 10-methylphenothiazine and methylviologen was found to be only weakly dependent on the ligand substitutions. Intramolecular long-range electron transfer from phenothiazine to photoexcited iridium(III) in the dyads is slow due to the occurrence of a Coulomb barrier. Consequently, an electron-transfer photoproduct is only observable in the transient absorption spectrum, of a donorbridge-acceptor molecule with a fluorinated photosensitizer that exhibits a very long excited-state lifetime. A flashquench technique is necessary for detection of an electrontransfer product in the dyad with a non-fluorinated photosensitizer. The occurrence of a Coulomb barrier associated with intramolecular (excited-state) long-range electron transfer in the dyads with cyclometalated iridium(III) photosensitizers represents an important difference to previously investigated similar donor-bridge-acceptor molecules with photosensitizers based on d6 metal diimine complexes.
Bromination of 2,2'-bipyridile
Zdravkov,Khimich
, p. 1200 - 1202 (2006)
A simple and convenient procedure was developed for the synthesis of 5,5'-dibromo-2,2'-bipyridyl providing the target compound in a high yield without the chromatographic separation of the reaction mixture. Polybromo derivatives of 2,2'-bipyridyl were isolated and characterized for the first time. Nauka/Interperiodica 2006.
Development of high dielectric polyimides containing bipyridine units for polymer film capacitor
Peng, Xinwen,Xu, Wenhui,Chen, Linlin,Ding, Yichun,Xiong, Tianrou,Chen, Shuiliang,Hou, Haoqing
, p. 93 - 98 (2016)
Polymer dielectrics with high dielectric constant, low dielectric loss, high breakdown strength, and high temperature capability are attractive for applications such as capacitive energy-storage. Commercially available polymer dielectrics such as biaxially oriented polypropylene (BOPP), poly(ethylene terephthalate) (PET), poly(ethylene naphthalate) (PEN), polycarbonate (PC), and poly(vinylidene) fluoride (PVDF) can be just operated below 200 °C. Great effort has been put into exploring high temperature polymer dielectrics to fulfill the demand of high temperature applications, such as the aerospace and military power supply. In this study, a series of polyimides containing bipyridine units with good dielectric performance and high temperature capability were prepared by using a newly synthesized diamine monomer, (5,5′-bis [(4-amino) phenoxy]-2,2′-bipyridine (BPBPA)). These polyimides possessed high dielectric constant of the as-synthesized polyimides can be up to7.2, the dielectric loss was 3. Furthermore, the polyimides exhibited high glass transition temperature (Tg) of 275–320 °C and tensile strengths of 175–221 MPa. These obtained polyimides promise potential applications in high temperature flexible polymer film capacitor operated at high temperature.
Molecular Tectonics: Design of Enantiopure Luminescent Heterometallic Ir(III)-Cd(II) Coordination Network
Xu, Chaojie,Guenet, Aurélie,Kyritsakas, Nathalie,Planeix, Jean-Marc,Hosseini, Mir Wais
, p. 10429 - 10439 (2015)
With the aim of combining luminescence and chirality in heterometallic Ir(III)-Cd(II) coordination networks, synthetic strategies for the formation of new Ir(III)-based chiral metallatectons ([Ir(dFppy)2(1)][PF6]), both as a racemic mixture of Δ and Λ enantiomers (rac-[Ir(dFppy)2(1)][PF6]) and as enantiopure complexes (Δ-[Ir(dFppy)2(1)][PF6] and Λ-[Ir(dFppy)2(1)][PF6]), were developed. The final compounds were characterized both in solution and in the crystalline phase. Notably, their crystal structures were determined by single crystal X-ray diffraction, and their photophysical properties in solution and in the solid state were investigated. Combination of the cationic linear metallatecton with Cd2+ iodide salt ([CdI3]-), behaving as an anionic two-connecting node, leads to the formation of 1D chiral and neutral heterometallic Ir(III)-Cd(II) luminescent coordination networks both as a racemic mixture and as enantiomerically pure infinite architectures. The latter have been structurally studied in the solid state by X-ray diffraction both on single crystals and on microcrystalline powders. The infinite coordination networks display phosphorescence in the solid state at ca. 600 nm upon excitation at 400 nm.
π-conjugated chelating polymers with charged iridium complexes in the backbones: Synthesis, characterization, energy transfer, and electrochemical properties
Liu, Shu-Juan,Zhao, Qiang,Chen, Run-Feng,Deng, Yun,Fan, Qu-Li,Li, Fu-You,Wang, Lian-Hui,Huang, Chun-Hui,Huang, Wei
, p. 4351 - 4361 (2006)
A series of π-conjugated chelating polymers with charged iridium (Ir) complexes in the backbones were synthesized by a Suzuki polycondensation reaction, leading to homogeneous polymeric materials that phosphoresce red light. The fluorene and bipyridine (bpy) segments were used as polymer backbones. 5.5′-Dibromobipyridine served as a ligand to form a charged iridium complex monomer with 1-(9′9-dioctylfluorene-2-yl)isoquinoline (Fiq) as the cyclometalated ligand. Chemical and photophysical characterization confirmed that Ir complexes were incorporated into the backbones as one of the repeat units by means of the 5.5′-dibromobipyridine ligand. Chelating polymers showed almost complete energy transfer from the host fluorene segments to the guest Ir complexes in the solid state when the feed ratio was 2 mol%. In the films of the corresponding blend system, however, energy transfer was not complete even when the content of Ir complexes was as high as 16 mol%. Both intra- and in termolecular energy-transfer processes existed in this host-guest system, and the intramolecular energy transfer was a more efficient process. All chelating polymers displayed good thermal stability, redox reversibility, and film formation. These chelating polymers also showed more efficient energy transfer than the corresponding blended system and the mechanism of incorporation of the charged Ir complexes into the π-conjugated polymer backbones efficiently avoided the intrinsic problems associated with the blend system, thus offering promise in optoelectronic applications.
Synthesis of Nitrile-Functionalized Polydentate N-Heterocycles as Building Blocks for Covalent Triazine Frameworks
Debruyne, Maarten,Everaert, Jonas,Heugebaert, Thomas S. A.,Stevens, Christian V.,Van Der Voort, Pascal,Van Hecke, Kristof,Van Speybroeck, Veronique,Vanden Bussche, Flore
, (2021/10/21)
Covalent triazine frameworks (CTFs) based on polydentate ligands are highly promising supports to anchor catalytic metal complexes. The modular nature of CTFs allows to tailor the composition, structure, and function to its specific application. Access to a broad range of chelating building blocks is therefore essential. In this respect, we extended the current available set of CTF building blocks with new nitrile-functionalized N-heterocyclic ligands. This paper presents the synthesis of the six ligands which vary in the extent of the aromatic system and the denticity. The new building blocks may help in a rational design of enhanced support materials in catalysis.
