نتایج جستجو برای: hammett constant

تعداد نتایج: 218513  

Journal: :Journal of the American Chemical Society 2014
Juncong Jiang Felipe Gándara Yue-Biao Zhang Kyungsu Na Omar M Yaghi Walter G Klemperer

Superacids, defined as acids with a Hammett acidity function H0 ≤ -12, are useful materials, but a need exists for new, designable solid state systems. Here, we report superacidity in a sulfated metal-organic framework (MOF) obtained by treating the microcrystalline form of MOF-808 [MOF-808-P: Zr6O5(OH)3(BTC)2(HCOO)5(H2O)2, BTC = 1,3,5-benzenetricarboxylate] with aqueous sulfuric acid to genera...

Journal: :Bulletin of the Chemical Society of Japan 1969

2009
F. L. Waelbroeck R. D. Hazeltine P. J. Morrison

An isothermal truncation of the electromagnetic gyrofluid model of Snyder and Hammett Phys. Plasmas 8, 3199 2001 is shown to be Hamiltonian. The corresponding noncanonical Lie–Poisson bracket and its Casimir invariants are presented. The invariants are used to obtain a set of coupled Grad–Shafranov equations describing equilibria and propagating coherent structures. © 2009 American Institute of...

2014
Heather M. Neu Tzuhsiung Yang Regina A. Baglia Timothy H. Yosca Michael T. Green Matthew G. Quesne Sam P. de Visser David P. Goldberg

Addition of anionic donors to the manganese(V)-oxo corrolazine complex Mn(V)(O)(TBP8Cz) has a dramatic influence on oxygen-atom transfer (OAT) reactivity with thioether substrates. The six-coordinate anionic [Mn(V)(O)(TBP8Cz)(X)](-) complexes (X = F(-), N3(-), OCN(-)) exhibit a ∼5 cm(-1) downshift of the Mn-O vibrational mode relative to the parent Mn(V)(O)(TBP8Cz) complex as seen by resonance ...

Journal: :Drug metabolism and disposition: the biological fate of chemicals 1998
T Yoshioka T Uematsu

The formation of N-hydroxy-N-arylacylamides from nitroso aromatic compounds and 2-oxo acids was investigated using rat liver subcellular fractions. Activities were found in both mitochondria and cytosol, except for activities for phenylpyruvate and glyoxylate; the former did not produce N-hydroxy-N-phenylphenylacetamide and the latter nonenzymatically produced N-hydroxy-N-phenylformamide with n...

Journal: :Chemical communications 2014
John Gräsvik Jason P Hallett Trang Quynh To Tom Welton

Introduced here is a quick, simple, robust method to measure acidity in ionic liquid (IL) systems by the use of the NMR-probe mesityl oxide. Acidity corresponding to a Hammett acidity of -1 to -9 can be measured reliably using this technique, a range that vastly exceeds that of any single UV-vis probe.

Journal: :Physical chemistry chemical physics : PCCP 2015
Lijuan Shen Ruowen Liang Mingbu Luo Fenfen Jing Ling Wu

UiO-66-X (X = H, NH2, NO2, Br) have been successfully synthesized and tested for their photocatalytic activity in water treatment. Results show that electronic effect of the ligand substituents greatly affects the photocatalytic activity of UiO-66. The rates obtained by different substituents are linearly correlated with their Hammett coefficients.

Journal: :Organic letters 2005
Marino J E Resendiz Miguel A Garcia-Garibay

[reaction: see text] The relative quantum yields and chemical efficiencies of crystalline p,p'-disubstituted 1,3-diphenyl-2-propanones with 4-MeO, 4-Me, 4-F, 4-CF3, and 3,4-diMeO groups were determined by parallel irradiation of polycrystalline samples. Variations in quantum yields that span a factor of 4 are analyzed in terms of the effects of substituents on the stability of the benzylic radi...

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