Search results
Results From The WOW.Com Content Network
In 1962, Edwards and Pearson (the latter of HSAB theory) introduced the phrase alpha effect for this anomaly. He offered the suggestion that the effect was caused by a transition state (TS) stabilization effect: on entering the TS the free electron pair on the nucleophile moves away from the nucleus, causing a partial positive charge which can be stabilized by an adjacent lone pair as for ...
The electron pair (:) from the nucleophile (Nuc:) attacks the substrate (R−LG), forming a new covalent bond Nuc−R−LG. The prior state of charge is restored when the leaving group (LG) departs with an electron pair. The principal product in this case is R−Nuc. In such reactions, the nucleophile is usually electrically neutral or ...
The Cieplak effect relies on the stabilizing interaction of mixing full and empty orbitals to delocalize electrons, known as hyperconjugation. [2] When the highest occupied molecular orbital of one system and the lowest unoccupied molecular orbital of another system have comparable energies and spatial overlap, the electrons can delocalize and sink into a lower energy level.
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases. Nucleophilic describes the affinity of a nucleophile to bond with positively charged ...
The electron pair (:) from the nucleophile (Nuc) attacks the substrate (R−LG) and bonds with it. Simultaneously, the leaving group (LG) departs with an electron pair. The principal product in this case is R−Nuc. The nucleophile may be electrically neutral or negatively charged, whereas the substrate is typically neutral or positively charged.
Examples include ((CH 3) 3 CCH 2)Ta=CHC(CH 3) 3 [9] and Os(PPh 3) 2 (NO)Cl(=CH 2). [10] Orbital interaction in the bonding of a Schrock carbene. Both the metal and carbon provide 2 unpaired electron each, forming the double bond. Bonding in such complexes can be viewed as the coupling of a triplet state metal and triplet carbene, forming a true ...
The first isolation of a nucleophilic aluminium center was achieved in 2018 by Aldridge, Goicoechea and coworkers when they were able to synthesize the first aluminyl anion, [5] following the discoveries of gallium [6] [7] [8] and indium [9] analogues, heavier group 13 analogues which are more stable than aluminium in the lower +1 oxidation ...
[2] [3] [4] This type of reaction is also called a 1,2-nucleophilic addition. The stereochemistry of this type of nucleophilic attack is not an issue, when both alkyl substituents are dissimilar and there are not any other controlling issues such as chelation with a Lewis acid, the reaction product is a racemate. Addition reactions of this type ...