- [Cu(P^P)(N^N)][PF6] compounds with bis(phosphane) and 6-alkoxy, 6-alkylthio, 6-phenyloxy and 6-phenylthio-substituted 2,2′-bipyridine ligands for light-emitting electrochemical cells
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We report a series of [Cu(P^P)(N^N)][PF6] complexes with P^P = bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) and N^N = 6-methoxy-2,2′-bipyridine (MeObpy), 6-ethoxy-2,2′-bipyridine (EtObpy), 6-phenyloxy-2,2′-bipyridine (PhObpy), 6-methylthio-2,2′-bipyridine (MeSbpy), 6-ethylthio-2,2′-bipyridine (EtSbpy) and 6-phenylthio-2,2′-bipyridine (PhSbpy). The single crystal structures of all twelve compounds have been determined and confirm chelating modes for each N^N and P^P ligand, and a distorted tetrahedral geometry for copper(i). For the xantphos-containing complexes, the asymmetrical bpy ligand is arranged with the 6-substituent lying over the xanthene ‘bowl'. The compounds have been characterized in solution by1H,13C and31P NMR spectroscopies, and their photophysical and electrochemical properties are described. They are yellow emitters and solid samples show photoluminescence quantum yields in the range up to 38%, with emission lifetimes ≤10.2 μs. On going from powder to frozen Me-THF, the excited state lifetimes increase which might suggest the presence of thermally activated delayed fluorescence (TADF). All the compounds have been tested in light-emitting electrochemical cells (LECs). Bright and stable LECs are obtained with complexes containing alkoxy- or phenyloxy-substituted ligands, making this family of compounds very relevant for the future development of copper-based electroluminescent devices.
- Alkan-Zambada, Murat,Keller, Sarah,Martínez-Sarti, Laura,Prescimone, Alessandro,Junquera-Hernández, José M.,Constable, Edwin C.,Bolink, Henk J.,Sessolo, Michele,Ortí, Enrique,Housecroft, Catherine E.
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- Coupling of consecutive pyridine ring units for oligopyridine synthesis
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The reaction of 2-ethylsulfinyl-6-(ethylthio)pyridine (2), 6- ethylsulfinyl-6'-ethylthio-2,2'-bipyridine (6), and 6-ethylsulfinyl-6'''- ethylthio-2,2':6',2'':6'',2'''-quaterpyridine (10) with methylmagnesium bromide gave symmetric oligopyridines 6,6'-bis(ethylthio)-2,2'-bipyridine (4), 6,6'''-bis(ethylthio)-2,2':6',2'':6'',2'''-quaterpyridine (8), and 6,6'''''''-bis(ethylthio)- 2,2':6',2'':6'',2''':6''',2'''':6'''',2''''':6''''',2'''''':6'''''',2''''''- octipyridine (12) in respective yields of 70, 56, and 3%. On the other hand, the reaction of 6 and 10 with 2-(6-bromopyridinyl)lithium and 6-(2,2'- bipyridinyl)lithium gave the corresponding unsymmetric oligopyridines (15, 16, 13, and 19). The reaction with chiral (S)-2-{6-[1-(tert- butyldimethylsiloxy)ethyl]pyridinyl}lithium gave optically active oligopyridines (17) and (18) in 78 and 58% yields, respectively.
- Uenishi, Jun'ichi,Ueno, Tetsuya,Hata, Sin'ichiro,Nishiwaki, Kenji,Tanaka, Takakazu,Wakabayashi, Shoji,Yonemitsu, Osamu,Oae, Shigeru
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p. 341 - 351
(2007/10/03)
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- Synthesis of ω-(Bromomethyl)bipyridines and Related ω-(Bromomethyl)pyridinoheteroaromatics: Useful Functional Tools for Ligands in Host Molecules
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Pyridines and 2,2'-bipyridines have been employed as useful ligands in molecular recognition chemistries.Halomethyl-substituted bipyridine or oligopyridine derivatives were required for the assembly of bipyridine or oligopyridine units with a supporting mother functional part in artificial biofunctional molecules.A series of ω-(bromomethyl)bipyridines and related ω-(bromomethyl)pyridinoheteroaromatic compounds (types I-III) were synthesized in this paper.Preparation of oligopyridines and pyridinoheteroaromatic compounds have been carried out by either intermolecular ligand coupling of alkyl heteroaryl sulfoxide with pyridyllithium or intramolecular ligand coupling of pyridyl heteroaryl sulfoxide with methylmagnesium bromide for the type I compounds.The type II and III compounds were synthesized by addition of pyridyllithium to pyridinecarboxaldehyde.The ω-bromo group was introduced by radical bromination reaction of methylpyridyl group using NBS and BPO (dibenzoyl peroxide) or bromination of ω-(hydroxymethyl)pyridine using a combination of CBr4 and Ph3P.
- Uenishi, Jun'ichi,Tanaka, Takakazu,Nishiwaki, Kenji,Wakabayashi, Shoji,Oae, Shigeru,Tsukube, Hiroshi
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p. 4382 - 4388
(2007/10/02)
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- Ipso substitution of 2-alkylsulfinylpyridine by 2-pyridyllithium; a new preparation of oligopyridine and their bromomethyl derivatives
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Unsymmetrical and symmetrical 2,2'-bipyridines have been prepared. The methods applied are new and offer efficient syntheses of higher oligopyridines and their bromomethyl derivatives.
- Uenishi,Tanaka,Wakabayashi,Oae,Tsukube
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p. 4625 - 4628
(2007/10/02)
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