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An electric effect influences the structure, reactivity, or properties of a molecule but is neither a traditional bond nor a steric effect. [1] In organic chemistry , the term stereoelectronic effect is also used to emphasize the relation between the electronic structure and the geometry ( stereochemistry ) of a molecule.
If the electronegative atom (missing an electron, thus having a positive charge) is then joined to a chain of atoms, typically carbon, the positive charge is relayed to the other atoms in the chain. This is the electron-withdrawing inductive effect, also known as the -I effect. In short, alkyl groups tend to donate electrons, leading to the +I ...
The positive values that are listed in tables of E ea are amounts or magnitudes. It is the word "released" within the definition "energy released" that supplies the negative sign to Δ E . Confusion arises in mistaking E ea for a change in energy, Δ E , in which case the positive values listed in tables would be for an endo- not exo-thermic ...
Arrow pushing or electron pushing is a technique used to describe the progression of organic chemistry reaction mechanisms. [1] It was first developed by Sir Robert Robinson.In using arrow pushing, "curved arrows" or "curly arrows" are drawn on the structural formulae of reactants in a chemical equation to show the reaction mechanism.
The +M effect, also known as the positive mesomeric effect, occurs when the substituent is an electron donating group. The group must have one of two things: a lone pair of electrons, or a negative charge. In the +M effect, the pi electrons are transferred from the group towards the conjugate system, increasing the density of the system.
The order of the metals for this effect was the same as in Volta's series for contact-electricity, the most electropositive metals giving the largest photo-electric effect. Gold leaf electroscope demonstrating the photoelectric effect. When the electroscope disk is negatively charged with excess electrons, the gold leaves mutually repel.
Furthermore, theories have been put forward to take into account the effects of vibronic coupling on electron transfer, in particular, the PKS theory of electron transfer. [10] In proteins, ET rates are governed by the bond structures: the electrons, in effect, tunnel through the bonds comprising the chain structure of the proteins. [11]
In organic chemistry, neighbouring group participation (NGP, also known as anchimeric assistance) has been defined by the International Union of Pure and Applied Chemistry (IUPAC) as the interaction of a reaction centre with a lone pair of electrons in an atom or the electrons present in a sigma or pi bond contained within the parent molecule but not conjugated with the reaction centre.