Protonated Phosphazenes: Structures and Hydrogen-Bonding Organocatalysts for Carbonyl Bond Activation

2016 ◽  
Vol 358 (7) ◽  
pp. 1110-1118 ◽  
Author(s):  
Damien Jardel ◽  
Clotilde Davies ◽  
Frédéric Peruch ◽  
Stéphane Massip ◽  
Brigitte Bibal
Keyword(s):  
Hydrogen Bonding ◽  
Bond Activation ◽  
Carbonyl Bond

Weak Hydrogen Bonding Can Initiate Alkane C−H Bond Activation in Acidic Zeolites

2006 ◽  
Vol 110 (42) ◽  
pp. 20762-20764 ◽  
Author(s):  
Laura S. Sremaniak ◽  
Jerry L. Whitten ◽  
Matthew J. Truitt ◽  
Jeffery L. White
Keyword(s):  
Hydrogen Bonding ◽  
Bond Activation ◽  
Weak Hydrogen Bonding ◽  
Acidic Zeolites

Z−H Bond Activation in (Di)hydrogen Bonding as a Way to Proton/Hydride Transfer and H2 Evolution

2017 ◽  
Vol 24 (7) ◽  
pp. 1464-1470 ◽  
Author(s):  
Natalia V. Belkova ◽  
Oleg A. Filippov ◽  
Elena S. Shubina
Keyword(s):  
Hydrogen Bonding ◽  
Bond Activation ◽  
Hydride Transfer ◽  
H2 Evolution

Mild Friedel-Crafts Reactions inside a Hexameric Resorcinarene Capsule: C−Cl Bond Activation through Hydrogen Bonding to Bridging Water Molecules

2018 ◽  
Vol 130 (19) ◽  
pp. 5521-5526 ◽  
Author(s):  
Pellegrino La Manna ◽  
Carmen Talotta ◽  
Giuseppe Floresta ◽  
Margherita De Rosa ◽  
Annunziata Soriente ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Bond Activation ◽  
Water Molecules

scholarly journals New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions

2014 ◽  
Vol 10 ◽  
pp. 224-236 ◽  
Author(s):  
Helge Klare ◽  
Jörg M Neudörfl ◽  
Bernd Goldfuss
Keyword(s):  
Hydrogen Bonding ◽  
Catalytic Activity ◽  
High Activity ◽  
Michael Addition ◽  
Bond Activation ◽  
High Catalytic Activity ◽  
Open Chain ◽  
High Hydrogen ◽  
Michael Additions ◽  
Asymmetric Michael Addition

Ten novel hydrogen-bonding catalysts based on open-chain PV-amides of BINOL and chinchona alkaloids as well as three catalysts based on rigid cis-PV-cyclodiphosphazane amides of N 1,N 1-dimethylcyclohexane-1,2-diamine have been developed. Employed in the asymmetric Michael addition of 2-hydroxynaphthoquinone to β-nitrostyrene, the open-chain 9-epi-aminochinchona-based phosphorus amides show a high catalytic activity with almost quantitative yields of up to 98% and enantiomeric excesses of up to 51%. The cyclodiphosphazane catalysts show the same high activity and give improved enantiomeric excesses of up to 75%, thus representing the first successful application of a cyclodiphosphazane in enantioselective organocatalysis. DFT computations reveal high hydrogen-bonding strengths of cyclodiphosphazane PV-amides compared to urea-based catalysts. Experimental results and computations on the enantiodetermining step with cis-cyclodiphosphazane 14a suggest a strong bidentate H-bond activation of the nitrostyrene substrate by the catalyst.

Significant hydrogen-bonding effect on the reactivity of high-valent manganese(V)–oxo porphyrins in C–H bond activation: A DFT study

2015 ◽  
Vol 19 (11) ◽  
pp. 1197-1203 ◽  
Author(s):  
Abdolreza Rezaeifard ◽  
Hossein Kavousi ◽  
Heidar Raissi ◽  
Maasoumeh Jafarpour
Keyword(s):  
Hydrogen Bonding ◽  
Bond Activation ◽  
Nbo Analysis ◽  
Electronic Effects ◽  
Unusual Behavior ◽  
Aim Analysis ◽  
Oxidation Activity ◽  
Bonding Effect ◽  
Phenyl Rings ◽  
High Valent

The stereo electronic effects as well as hydrogen bonding effects of imidazole, pyridine and 2,6-dimethylpyridine as N-donor axial ligands on the C–H oxidation activity of high-valent manganese(V)–oxo meso-tetraphenylporphyrin (TPP) and meso-tetrakis(pentaflourophenyl)porphyrin (TPFPP), are investigated by DFT calculations. The electronic and steric properties of axial donors and porphyrin ligands affected on the activation energy of cyclohexane hydroxylation as well as the Mn–O bond strength of the oxo species in transition state. Imidazole with the strong [Formula: see text]-donating ability and the least steric hindrance showed greater co-catalytic activity than those of pyridine and in particularly hindered 2,6-Me2 pyridine in the presence of simple [(TPP)MnO][Formula: see text]. Nevertheless, the C–H bond activation by hindered and electron-deficient perfluorinated catalyst [(TPFPP)MnO][Formula: see text] is in the order of pyridine >2, 6-Me2 pyridine >imidazole. AIM analysis showed hydrogen bonding (HB) between the C–H [Formula: see text] bonds of pyridine (C[Formula: see text]-H of ring) and 2,6-Me2Py (C[Formula: see text]-H of methyl groups) with ortho-C–F bond of phenyl rings of TPFPP in Mn[Formula: see text]O species (C–H…..F–C hydrogen bond) which might be responsible for this unusual behavior. These results are supported by natural bond orbital (NBO) analysis.

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