- Coumaraz-2-on-4-ylidene: Ambiphilic N-Heterocyclic Carbenes with a Tunable Electronic Structure
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Herein, a coumaraz-2-on-4-ylidene (1) as a new example of an ambiphilic N-heterocyclic carbene, having electronic properties that can be fine-tuned, is reported. The N-carbamic and aryl groups on the carbene carbon center provide exceptionally high electrophilicity and nucleophilicity simultaneously to the carbene center, as evidenced by the 77Se NMR chemical shifts of their selenoketone derivatives and the CO stretching strengths of their rhodium carbonyl complexes. Since the precursors of 1 could be synthesized from various functionalized Schiff bases in a practical and scalable manner, the electronic properties of 1 can be fine-tuned in a quantitative and predictable way by using the Hammett σ constant of the functional groups on aryl ring. The facile electronic tuning capability of 1 may be applicable to eliciting novel properties in main-group and transition-metal chemistry.
- Song, Hayoung,Kim, Hyunho,Lee, Eunsung
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supporting information
p. 8603 - 8607
(2018/07/14)
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- Syntheses and crystal structures of ruthenium complexes with bidentate salicylaldiminato and dithiophosphato ligands
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Treatment of the bidentate Schiff base 2-[(2,6-diisopropyl-phenylimino)-methyl]-phenol (HL1) with one equivalent of (Et4N)[RuCl4(MeCN)2] in the presence of triethylamine afforded (Et4N)[RuCl3(κ2
- Tang, Li-Hua,Wu, Fule,Lin, Hui,Jia, Ai-Quan,Zhang, Qian-Feng
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p. 329 - 335
(2018/05/22)
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- Vanadium(III) phenoxyimine complexes for ethylene or ε-caprolactone polymerization: Mononuclear versus binuclear pre-catalysts
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The mononuclear {[C6H4NCH(ArO)]2VCl(THF)} (Ar = 2,4-t-Bu2C6H2 (1), Ar = C 6H4 (2)), {O[C6H4NCH(ArO)] 2}VCl(THF) (Ar = 2,4-t-Bu2C6H2 (3), Ar = C6H4 (4)) and the binuclear vanadium(iii) complexes {[C6H4NCH(ArO)]VCl2(THF)2} 2(μ-CH2CH2) (Ar = 2,4-t-Bu2C 6H2 (5), Ar = C6H4 (6)), have been synthesized and fully characterized. The compounds [C6H 5NCH(ArO)]VCl2(THF)2 (Ar = 2,4-t-Bu 2C6H2 (7), Ar = C6H4 (8)), [2,4,6-Me3-C6H2NCH(ArO)]VCl2 (Ar = 2,4-t-Bu2C6H2 (9), Ar = C 6H4 (10)) and [2,6-i-Pr2-C6H 3NCH(ArO)]VCl2(THF)2 (Ar = 2,4-t-Bu 2C6H2 (11), Ar = C6H4 (12)), {μ-CH2CH2[NCH(C6H4O)] 2VCl(THF)} (14) and {C6H4[NCH(C 6H4O)]2VCl(THF)} (15) were synthesized for comparative polymerization studies. The dizwitterionic compound [2,6-i-Pr 2-C6H3N+(H)CH(C6H 4O)]2VCl2O (13) was also isolated, and presumably formed via a fortuitous hydrolysis reaction. The complexes 2, 5 and 13 have been structurally characterized; the molecular structure of the parent ligand (L5) in 5 is also reported. All complexes have been screened for ethylene as well as ε-caprolactone polymerization, and results are compared against those for known related mono- and bi-nuclear counterparts to evaluate for possible cooperative effects. The compounds 10 and 12 have been supported on modified SiO2, analysed by XPS and subjected to homo-polymerization (ethylene) and co-polymerization (1-hexene and ethylene) studies. The Royal Society of Chemistry 2013.
- Clowes, Lucy,Walton, Mark,Redshaw, Carl,Chao, Yimin,Walton, Alex,Elo, Pertti,Sumerin, Victor,Hughes, David L.
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p. 152 - 160
(2013/04/10)
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- Structural diversity and versatility for organoaluminum complexes supported by mono- and di-anionic aminophenolate bidentate ligands
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The present contribution describes the synthesis and structural characterization of structurally diverse organoaluminum species supported by variously substituted aminophenolate-type ligands: these Al complexes are all derived from the reaction of AlMesu
- Maisse-Franois, Aline,Azor, Laurine,Schmitt, Anne-Laure,Coquel, Ariane,Brelot, Lydia,Welter, Richard,Bellemin-Laponnaz, Stéphane,Dagorne, Samuel
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experimental part
p. 4248 - 4256
(2012/01/13)
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- Zinc(II) homogeneous and heterogeneous species and their application for the ring-opening polymerisation of rac-lactide
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Schiff base ligands (L1H-L8H) have been prepared and complexed to Zn II centres. All eight complexes have been characterised by single-crystal X-ray diffraction methods, multinuclear NMR spectroscopy and elemental analysis. It was shown that fo
- Jones, Matthew D.,Davidson, Matthew G.,Keir, Callum G.,Hughes, Laura M.,Mahon, Mary F.,Apperley, David C.
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experimental part
p. 635 - 642
(2009/05/06)
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- Synthesis and spectral [IR, 1H, 13C, and 11B] properties of 2-(N-arylsalicylaldimino)- 4,4,5,5-tetramethyl-1,3,2-dioxaborolanes
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Reactions in 1:1 molar ratio of 2-isopropoxy-4, 4, 5, 5tetramethyl-1, 3, 2-dioxaborolane with N-arylsali-cylaldimines (LH=HOC6 H4CH=NC6H5, HOC6H4CH=NC6H4Me2-2,6, HOC6H4CH=NC6H2Me3-2,4,6, HOC6H4CH=NC6H3Et2-2, 6, and HOC6H4CH=NC6H3Pr2-2, 6 in benzene afford new cyclic compounds of boron containing pinacolate and salicylaldiminate groups. These new derivatives have been characterized by elemental analysis and spectroscopic [IR, NMR (1H, 13C, and 11B)] studies as well as by molecular weight determinations.
- Goyal,Singh
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p. 638 - 641
(2007/10/03)
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