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An electron-withdrawing group (EWG) is a group or atom that has the ability to draw electron density toward itself and away from other adjacent atoms. [1] This electron density transfer is often achieved by resonance or inductive effects.
An electron donating group (EDG) or electron releasing group (ERG, Z in structural formulas) is an atom or functional group that donates some of its electron density into a conjugated π system via resonance (mesomerism) or inductive effects (or induction)—called +M or +I effects, respectively—thus making the π system more nucleophilic.
According to the captodative effect, the rate of a reaction is the greatest when both the EDG and EWG are able to delocalize the radical ion in the transition state structure. [ 7 ] Ito and co-workers observed the rate of addition reactions of aryl thiol radical to disubstituted olefins. [ 6 ]
Research Papers in Economics (RePEc) is a collaborative effort of hundreds of volunteers in many countries to enhance the dissemination of research in economics. The heart of the project is a decentralized database of working papers, preprints, journal articles, and software components. [1] The project started in 1997. [2]
The main academic full-text databases are open archives or link-resolution services, although others operate under different models such as mirroring or hybrid publishers. . Such services typically provide access to full text and full-text search, but also metadata about items for which no full text is availa
For example, in a normal-demand scenario, a diene bearing an electron-donating group (EDG) at C1 has its largest HOMO coefficient at C4, while the dienophile with an electron withdrawing group (EWG) at C1 has the largest LUMO coefficient at C2. Pairing these two coefficients gives the "ortho" product as seen in case 1 in the figure below.
For example, the results that overarching education reforms such as No Child Left Behind have had on Hispanic students show that improving their educational condition may not depend solely on improving schools or curricula but also on other factors such as the children’s’ socio-economic situation.
The AEA maintains EconLit, a searchable data base of citations for articles, books, reviews, dissertations, and working papers classified by JEL codes for the years from 1969. A recent addition to EconLit is indexing of economics journal articles from 1886 to 1968 [1] parallel to the print series Index of Economic Articles. [2]