Molecular zinc dihydride stabilized by N-heterocyclic carbenes

Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.

Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic...

Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.

Carbocations are one of the reaction intermediates formed during several nucleophilic substitutions or elimination reactions. A carbocation is an electron-deficient species with the central carbon atom having six electrons and three bonded atoms. The central carbon in a carbocation is sp2 hybridized with trigonal planar geometry. It has an empty p orbital perpendicular to the plane of the structure that can accept electrons. Thus, carbocations act as strong electrophiles and may react with any...

Carboxylic acids react with diazomethane in an ether solvent via alkylation at the carboxylate oxygen atom to give methyl esters of the corresponding acid with excellent yields.

Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.