- Mono- And Dinuclear α-Diimine Nickel(II) and Palladium(II) Complexes in C-S Cross-Coupling
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The usefulness of transition metal catalytic systems in C-S cross-coupling reactions is significantly reduced by air and moisture sensitivity, as well as harsh reaction conditions. Herein, we report four highly air- and moisture-stable well-defined mononuclear and bridged dinuclear α-diimine Ni(II) and Pd(II) complexes for C-S cross-coupling. Various ligand frameworks, including acenaphthene- and iminopyridine-based ligands, were employed, and the resulting steric properties of the catalysts were evaluated and correlated with reaction outcomes. Under aerobic conditions and low temperatures, both Ni and Pd systems exhibited broader substrate scope and functional group tolerance than previously reported catalysts. Over 40 compounds were synthesized from thiols containing alkyl, benzyl, and heteroaryl groups. Also, pharmaceutically active heteroaryl moieties are incorporated from thiol and halide sources. Notably, the bridged dinuclear five-coordinate Ni complex has outperformed the remaining three mono four- or six-coordinate complexes by giving almost quantitative yields across a broad substrate scope.
- Talukder, Md Muktadir,Miller, Justin T.,Cue, John Michael O.,Udamulle, Chinthaka M.,Bhadran, Abhi,Biewer, Michael C.,Stefan, Mihaela C.
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- Polystyrene resin-supported CuI-cryptand 22 complex: a highly efficient and reusable catalyst for the formation of aryl–sulfur bonds in aqueous media
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The air and moisture stable polystyrene resin-supported copper(I) iodide-cryptand-22 complex (PS-C22-CuI) behaves as an efficient and robust heterogeneous catalyst in the cross-coupling reaction of aryl halides and thiols in aqueous media. Moreover, the heterogeneous catalyst can be easily recovered by filtration and reused for five cycles without significant loss in activity.
- Rezaei, Nasrin,Movassagh, Barahman
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supporting information
p. 1625 - 1628
(2018/03/29)
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- Efficient nickel/N-heterocyclic carbene catalyzed C-S cross-coupling
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The cross-coupling reaction of aryl halides with aliphatic and aromatic thiols catalyzed by readily available Ni(OAc)2 with N-heterocyclic carbene (NHC) is reported. Ni(OAc)2/NHC catalyst showed good activities toward various aryl halides in C-S coupling reaction, even with aryl chlorides. Reactions occurred in excellent yields, broad scope, and high tolerance of functional groups.
- Guan, Pei,Cao, Changsheng,Liu, Yun,Li, Yunfei,He, Pan,Chen, Qian,Liu, Gang,Shi, Yanhui
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supporting information
p. 5987 - 5992
(2013/01/13)
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- Specific interactions in discotic liquid crystals
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A series of novel mesogens have been prepared by a five-fold Sonogashira reaction of terminal acetylenes with a functionalized pentabromophenol derivative. The corresponding side-chain substituted polymers were prepared by an analogous polymer substitution reaction. The mesogens differ in the nature of the substituents, i.e. CH2, O, S, SO2 and CONH groups, linking five hexyl tails to the core. A wide range of mesophases and corresponding transition temperatures have been detected, varying from low melting nematic phases to highly stable columnar phases. The wide spread in phase behaviour is described in terms of specific intermolecular interactions. The addition of planar electron deficient molecules resulted in the formation of charge transfer complexes. The observed stabilisation or destabilisation of the mesophases is explained by considering the complexation strength of the complex as well as steric factors.
- Kouwer, Paul H. J.,Jager, Wolter F.,Mijs, Wim J.,Picken, Stephen J.
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p. 458 - 469
(2007/10/03)
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