- Towards Ruthenium-Based Building Blocks for CuAAC Click Reactions: Challenges in Generating Ruthenium(II) Polypyridine Alkynes
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Ag+-free complexation of alkyne-bipyridines at ruthenium(II) polypyridine centers proceeds with surprisingly low yields. The alkyne-bipyridine-substituted ruthenium(II) polypyridine complexes in this work were characterized by NMR spectroscopy, ESI spectrometry, and single-crystal X-ray structural analysis. A detailed analysis of the side products revealed an unexpected carbon-carbon alkyne bond splitting promoted by the ruthenium(II) center, leading to the formation of a CO-RuII species, methyl-bipyridine, and a methyl-bipyridine-substituted ruthenium(II) complex accompanying the target product. The side products were characterized using complimentary methods including X-ray crystallography. A possible mechanism is suggested based on these side products and exemplary reaction studies. For the coordination reaction of alkyne-bipyridines with Ru(bpy)2Cl2 unexpected side reactions take place, forming a RuII-CO species and methyl-bipyridine. Here we give a detailed mechanism of the side reactions and an adequate workup procedure to obtain a pure alkyne-substituted ruthenium(II) polypyridine complex, which is the intended product.
- Zabarska, Natalia,Sorsche, Dieter,Heinemann, Frank W.,Glump, Susanne,Rau, Sven
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- Modular Synthesis of Elongated Phosphonate Bipyridines
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The synthesis and the photophysical properties of a series of bpy-R2 derivatives L1-L3 (bpy = 2,2′-bipyridine, R represents the substitution at the 4- and 4′-positions of the bpy) are described. R includes phosphonic ester groups as precursors for potent phosphonate anchoring groups, which enable immobilization on transition metal oxide semiconductor surfaces for applications like dye-sensitized solar cells (DSSCs) or dye-sensitized photoelectrosynthesis cells (DSPECs). The ligands L1-L3 differ in the length of conjugated linker units between bpy core and anchoring groups. Phenylene and triazole moieties serve as building blocks for linker elongation. The resulting adjustability of the distance between semiconductor and chromophore represents a viable route to improve cell efficiency, as it will allow tuning of charge carrier recombination and dye aggregation. Furthermore the photophysical studies of the free ligands reveal a pronounced effect of the aryl substitution. The solid-state structures of L1 and L2 are reported within this contribution, enabling the determination of distances between bipyridine nitrogen donor and anchoring group.
- Braumüller, Markus,Sorsche, Dieter,Wunderlin, Markus,Rau, Sven
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- Highly efficient benzodifuran based ruthenium sensitizers for thin-film dye-sensitized solar cells
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The synthesis of 4,4′-dibenzodifuran-2,2′-bipyridine derivatives as ligands of organic ruthenium dyes for DSSC applications is described. Two new heteroleptic ruthenium complexes have been prepared and compared with commercially available N719 and Z907 dyes, using dip dyeing and flow dyeing methods in large area testing cells prepared for industrial purposes. The newly synthesized dyes revealed higher solar-to-electric energy conversion efficiency (η), measured at the AM1.5G conditions, up to 21% compared to N719 and up to 46% compared to Z907, and external quantum efficiency of 53%. These results can be explained by enhanced light-harvesting of the benzodifuran moiety of the dyes that is related to photocurrent.
- Bosiak, Mariusz J.,Rakowiecki, Marcin,Wolan, Andrzej,Szlachta, Jolanta,Stanek, Edyta,Cycoń, Dawid,Skupień, Krzysztof
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- Luminescent Re(I)/Au(I) Species As Selective Anticancer Agents for HeLa Cells
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A series of neutral and cationic heterotrimetallic complexes of the type fac-[Re(CO)3(bipy(CC)2-(AuL)2)X]n, where bipy(CC)2 is 4,4′-alkynyl-2,2′-bipyridine; L is either triphenylphosphine (PPh3/
- Fernández-Moreira, Vanesa,Gimeno, M. Concepción,Luengo, Andrés,Marzo, Isabel,Redrado, Marta
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- A modular 'click' approach to substituted 2,2′-bipyridines
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The CuAAC reaction was used for the development of a click approach to a series of triazole-substituted bipyridinyl derivatives. 4,4′-Diethinyl 2,2′-bipyridine and 4,4′-diazido 2,2′-bipyridine were synthesized and tested in the cycloaddition reactions. While 4,4′-diazido 2,2′-bipyridine revealed unreactive in CuAAC reactions, its corresponding N,N′-dioxide afforded the expected cycloaddition product. Georg Thieme Verlag Stuttgart.
- Fabbrizzi, Pierangelo,Cecconi, Bianca,Cicchi, Stefano
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scheme or table
p. 223 - 226
(2011/03/22)
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- Multidentate pyridyl-based ligands in the coordination-driven self-assembly of palladium metallo-macrocycles
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In the current study, a convenient way is presented to synthesize one ditopic and two tetratopic pyridine-based ligands, which are then used to construct metallo-supramolecular polygons. The tetratopic ligands offer two different metal-binding sites, one
- Brusilowskij, Boris,Schalley, Christoph A.
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experimental part
p. 469 - 477
(2011/03/21)
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- Tris(2,2′-bipyridyl)ruthenium(II) with branched polyphenylene shells: A family of charged shape-persistent nanoparticles
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(Figure Presented) Cores for thought: Dendrimers based on an octahedral symmetry and with a central positively charged transition-metal complex have been prepared up to the third generation (see schematic representation). The shape-persistent dendrimers with a high density of aromatic rings are accessible by either a partly convergent synthesis or a divergent strategy in which the metal complex proved to be stable to high-temperature Diels-Alder reactions.
- Haberecht, Monika C.,Schnorr, Jan M.,Andreitchenko, Ekaterina V.,Clark Jr., Christopher G.,Wagner, Manfred,Muellen, Klaus
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supporting information; experimental part
p. 1662 - 1667
(2009/02/06)
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- Ruthenium complexes containing fully conjugated ligands terminated with thiol groups
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Bipyridine- and terpyridine-based ruthenium complexes containing fully conjugated ligands terminated with thiol groups were prepared and immobilized in self-assembled monolayers of alkanethiolates on gold surface, single molecules of which were observed w
- Otsuki, Joe,Kameda, Hiroyuki,Tomihira, Sota,Sakaguchi, Hiroshi,Takido, Toshio
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p. 610 - 611
(2007/10/03)
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- General method for the preparation of alkyne-functionalized oligopyridine building blocks
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A large series of alkyne-substituted oligopyridines based on 2,2′-bipyridine, 1,10-phenanthroline, 2,2′:6′,2″-terpyridine, or 1,8-naphthyridine substrates has been synthesized and fully characterized. The palladium(0)-catalyzed coupling of bromo- or chloro-substituted derivatives with (trimethylsilyl)-acetylene proceeds readily in diisopropylamine under ambient conditions giving good yields of the corresponding alkyne-substituted substrates oligoPy(C≡C)SiMe3. The terminal monoynes oligoPyC≡CH become available upon treatment with K2CO3 in methanol. Stepwise homologation of the acetylene function by Cadiot-Chodkiewicz coupling of oligoPyC≡CH with (bromoethynyl)-triethylsilane (BrC≡CSiEt3) affords, in good yield, the silylated diynes oligoPy(C≡C)2SiEt3, from which the terminal diynes oligoPy(C≡C)2H are formed by treatment with aqueous methanolic alkali. Reaction of oligoPy(C≡C)2H with BrC≡CSiEt3 yields the silylated triynes oligoPy(C≡C)3SiEt3 in modest yield. Further homologation is limited by nucleophilic attack of n-propylamine at the C-2 carbon of the alkyne chain, giving rise to a mixture of cis/cis (48%), cis/trans (33%), and trans/ trans (19%) enaminediyne compounds 21a-c. Glaser oxidative self-coupling of the terminal diynes provides access to ditopic bipyridine or terpyridine ligands oligoPy(C≡C)4oligoPy comprising a tetrayne spacer. Quantitative formation of air-stable copper(I) complexes is described for the 6,6′-substituted ligands. A single crystal X-ray structure of complex 22a shows that the two ligands are interlocked around the copper(I) center in a pseudotetrahedral arrangement, similar to the structure deduced from NMR and FAB+ data. The synthetic methods reported herein represent a valuable approach to the large-scale preparation of alkyne-functionalized oligopyridines.
- Ziessel, Raymond,Suffert, Jean,Youinou, Marie-Therese
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p. 6535 - 6546
(2007/10/03)
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- TOWARDS MOLECULAR ELECTRONICS: A NEW FAMILY OF AROMATIC POLYIMINE CHELATES SUBSTITUTED WITH ALKYNE GROUPS
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Bromo and chloro polyimines react with trimethylsilylacetylene in the presence of Pd(PPh3)2Cl2/CuI and diisopropylamine to give new substituted polyimines 1a to 8a.These compounds are deprotected with K2CO3 in MeOH/THF to produce the corresponding terminal alkynes 1b to 8b.
- Suffert, Jean,Ziessel, Raymond
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p. 757 - 760
(2007/10/02)
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