- Synthesis and characterization of para-pyridine linked NHC palladium complexes and their studies for the Heck-Mizoroki coupling reaction
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This paper describes the synthesis of 1-(pyridine-4-ylmethyl) NHC and their Pd(ii) and Ag(i) complexes, which are fully characterized. Interestingly, we have also synthesized a Pd complex 3a-CO3 using a more direct treatment of K2CO3 with PdCl2. 3a-CO 3 represents the first reported solid structure of a Pd η2-carbonato complex stabilized by an NHC framework. 3a-CO 3 can be easily converted to a PdCl2 derivative by treating it with chloroform. We have found these palladium complexes mediate the Heck-Mizoroki coupling with a low catalyst loading. Furthermore, we also expand such catalytic manifold toward constructing fused polyaromatic substrates, a highly useful class of compounds in optoelectronic chemistry.
- Liu, Ya-Ming,Lin, Yi-Chun,Chen, Wen-Ching,Cheng, Jen-Hao,Chen, Yi-Lin,Yap, Glenn P. A.,Sun, Shih-Sheng,Ong, Tiow-Gan
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experimental part
p. 7382 - 7389
(2012/07/31)
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- Highly selective cis-trans photoisomerization of 1-pyrenylethylenes: Relations between the modes of isomerization and potential energy surfaces
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Among 1-pyrenylethylenes with an alkyl (t-butyl) or an aryl (phenyl) group on the ss ethylenic carbon, 1-(3,3-dimethyl-1-butenyl)pyrene (BP) undergoes cis-to-trans one-way isomerization on benzil sensitization, whereas 1-styrylpyrene (SP) undergoes mutual isomerization between the cis and trans isomers to afford an extremely high photostationary state composition (98%) of the trans isomer. Transient spectroscopy and measurements of the isomerization quantum yields revealed that the trans triplet state is the most stable and populated conformation on the triplet energy surface for both BP and SP; however, a higher degree of stabilization of the trans conformation for BP than for SP compared to the perpendicularly twisted conformation makes BP and SP one-way and two-way isomerizing, respectively.
- Okamoto, Hiroaki,Arai, Tatsuo,Sakuragi, Hirochika,Tokumaru, Katsumi
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p. 2881 - 2890
(2007/10/02)
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- SOME PECULIARITIES OF DIARYLETHYLENES WITH 3-PYRENYL FRAGMENTS.
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An investigation of the spectral-fluorescent properties and direct photoisomerization of diarylethylenes with 3-pyrenyl fragments is presented.
- Kovalenko,Abdukadirov,Gerko,Alfimov
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p. 607 - 612
(2007/10/02)
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