Results 11 to 20 of about 1,896 (172)

Exchange Speed of Four-Component Nanorotors Correlates with Hammett Substituent Constants

Chemistry, 2021
Three distinct four-component supramolecular nanorotors were prepared, using, for the first time, bipyridine instead of phenanthroline stations in the stator.
Yi-Fan Li, Amit Ghosh, Pronay Kumar Biswas, Suchismita Saha, Michael Schmittel   +4 more
doaj   +1 more source

A comparative LFER study of the reactivity of pyridineacetic, pyridineacetic acids N-oxide and substituted phenylacetic acids with diazodiphenylmethane in various alcohols [PDF]

Journal of the Serbian Chemical Society, 2000
Rate constants have been determined for the reactions of diazodiphenylmethane (DDM) with 3- and 4-pyridineacetic acid, 3- and 4-pyridineacetic acid N-oxide and some meta- and para-substituted phenylacetic acids in twelve alcohols. The determined
Drmanić Saša Z., Jovanović Bratislav Ž., Mišić-Vuković Milica M.   +2 more
doaj   +3 more sources

A Theoretical Study of the Relationship between the Electrophilicity ω Index and Hammett Constant σp in [3+2] Cycloaddition Reactions of Aryl Azide/Alkyne Derivatives

Molecules, 2016
The relationship between the electrophilicity ω index and the Hammett constant σp has been studied for the [2+3] cycloaddition reactions of a series of para-substituted phenyl azides towards para-substituted phenyl alkynes. The electrophilicity ω index—a
Hicham Ben El Ayouchia, Hafid Anane, Moulay Lahcen El Idrissi Moubtassim, Luis R. Domingo, Miguel Julve, Salah-Eddine Stiriba   +5 more
doaj   +1 more source

The substituent effects on the 13c chemical shifts of the azomethine carbon atom of n-(phenyl substituted) salycilaldimines [PDF]

Journal of the Serbian Chemical Society, 2012
The Hammett correlations between 13C-NMR chemical shifts of the azomethine carbon atom and the corresponding substituent constants for thirtheen Schiff bases were established.
Drmanić Saša Ž., Marinković Aleksandar D., Nikolić Jasmina B., Jovanović Bratislav Ž.   +3 more
doaj   +1 more source

Ferrocene-Containing Pseudorotaxanes in Crystals: Aromatic Interactions with Hammett Correlation

Molecules, 2022
Single crystals of pseudorotaxanes, [(FcCH2NH2CH2Ar)(DB24C8)][PF6] (DB24C8 = dibenzo[24]crown-8, Fc = Fe(C5H4)(C5H5), Ar = -C6H3-3,4-Cl2, -C6H3-3,4-F2, -C6H4-4-F, -C6H4-4-Cl, -C6H4-4-Br, -C6H3-3-F-4-Me, -C6H4-4-I) and [(FcCH2NH2CH2C6H4-4-Me)(DB24C8)][Ni ...
Yuji Suzaki, Tomoko Abe, Asami Takei, Yugo Fukuchi, Take-aki Koizumi, Kohtaro Osakada, Masaki Horie   +6 more
doaj   +1 more source

تعیین ثوابت تأین بعض قواعد شف المشتقة من الفانلین والأنلین ومعوضاته بالطریقة التسحیحیة الطیفیة (تطبیق علاقة هامت) [PDF]

مجلة ابحاث كلية التربية الاساسية, 2023
شتمل البحث على تحضیر تسع مرکبات من قواعد شف من تفاعل التکاثف لالدیهاید الفانلین مع معوضات الانلین، إن ثوابت التأین لـ 3-میثوکسی-4-هیدروکسی بنزالدینیلین ومعوضاته بمجموعة النایترو بموقع اورثو ومیتا ومجموعتی المثیل والکلور فی موقع اورثو ومیتا وبارا تم ...
رواء داؤد
doaj   +1 more source

Determination of Hammett Sigma Constants by Intramolecular Hydrogen Bonding [PDF]

Nature, 1958
THE extensive literature that exists concerning Hammett's σ-constants has been subjected to several recent reviews, including a compilation and examination of available data1, a discussion of the significance and limitations of the concepts involved2, and an attempt to deduce best values and probable errors for the σ-values3.
A. T. SHULGIN, A. W. BAKER
openaire   +1 more source

Kinetic Analysis of Transmetalation at Prototypical Nickel(II) Catalyst Species: Rates, Mechanisms, and Implications for Catalysis

Angewandte Chemie, EarlyView.
A 31P{1H} NMR method enabling direct measurement of transmetalation at Ni(II) is disclosed, providing an extensive kinetic dataset. Rates span five orders of magnitude and exhibit strong ligand dependence, with monodentate ligands promoting transmetalation.
Nicholas S. D. Solomon, Xuechun Huang, Christopher Richardson, Sinead T. Keaveney   +3 more
wiley   +2 more sources

Water, Alcohols, Amines, and Amides as Formal Hydrogen‐Atom‐Transfer Reagents Through Activation With Redox‐Active Lewis Acids

Angewandte Chemie, EarlyView.
Protic molecules containing strong O─H or N─H bonds typically resist hydrogen‐atom abstraction because of the high reactivity of the resulting heteroatom‐centered radicals. However, association of the protic molecules with redox‐active Lewis acids can provide powerful hydrogen‐atom donors or proton‐coupled‐electron‐transfer reagents.
Petra Vojáčková, Armido Studer
wiley   +2 more sources

QUANTITATIVE FLUORESCENCE INTENSITYSTRUCTURE RELATIONSHIPS OF CERTAIN QUINOLONE-METAL CHELATES [PDF]

Bulletin of Pharmaceutical Sciences. Assiut University, 2006
A quantitative relationship was found between the relative fluorescence intensities of certain metal chelates of some quinolone antibacterials and their physicochemical parameters namely: the pKa1 (corresponding to the ionisation of the 3-carboxylic ...
Mohamed Abou-Elwafa, Samia El-Gizawi, Gamal Saleh, Michael El-Kommos   +3 more
doaj   +1 more source