Aromaticity Essays

Aromaticity can be termed as a chemical property of conjugated cycloalkenes. Aromaticity deals with the uncommon stability of benzene and its derivatives, which is caused by the ability of the electrons in the p-orbitals to delocalize and act as a framework to generate planar molecules. A molecule is only considered aromatic due to the fact that it is cyclic, that it follows the Huckel’s Rule and lastly that each element must have a p-orbital. Antioxidants play and important role in health. It can

In the process of performing a synthesis that include and aromatic ring there are several characteristics that need to taken into consideration such as, are there any substituents attached to the aromatic ring and if so, the type of substituent is important. Depending on the substituent that is bonded to the aromatic ring affects the position of additional substituents that are added. The substituents that are present on the aromatic ring can be identified as either as activating groups or deactivating

These two strong acids mix together to form a nitronium ion intermediate which is extremely electrophilic. The strong electrophile is needed since the first mechanistic step of the electrophilic aromatic substitution reaction results in a loss or aromaticity

Undergoing this reaction requires two steps. The first step is the addition of the electrophile, which in this lab was the Nitronium ion formed by the dilute nitric acid solution. This is the rate determining step for this reaction, as during this step aromaticity is lost and the arenium ion is formed. The position of the electrophile to be added is determined by how well the arenium ion can be stabilized once the initial addition occurs. In the case of phenol the greatest stabilization occurs when the electrophile

the hypothetical translation of a gene product. GRAVY is the arithmetic mean of the hydropathic indices of each amino acid [40]. GRAVY has been used to quantitatively assess the major (PCA) trends in the usage of amino acid E. coli genes [30]. An aromaticity score (Aromo) determines the frequency of the aromatic amino acids (Phe, tyr and trp) in the hypothetical translation of a gene product. According to Lobry (2000), the strongest trend variation in the composition of amino acids in E. coli genes

is part of tetra-pyrollic family and it has nitrogen in all meso-positions[3]. As mentioned before the compound has planar structure with an 18 π-electron system as predicted by Erich Hückel’s theory of aromaticity. The compound has four benzenes with 16 reactive sites because of this aromaticity and the covalent coordination of the central metal the compound is stable. So far, over 5000 of Phthalocyanine compounds have been prepared.[1] Thousands of tons of Phthalocyanine is produced annually

bond in benzene (acting as a nucleophile) and form the cyclohexadienyl cation intermediate and the tetrachloroaluminate anion. The anion then acts as a base to remove a proton from the ring and reform the initial Lewis acid. The ring regains its aromaticity and the product, an aromatic ring with an acyl substituent is fully synthesized.

positive charge. The reaction rate is determined by the rate at which the intermediate arenium ion forms. This intermediate arenium ion further undergoes deprotonation by the base yielding Methyl-m-nitrobenzoate. This leads to a restoration of the aromaticity of the ring. The bonding of the carbomethoxy group to benzene is based on the determination of the group as to where the electrophile bonds with the benzene ring. There are two types of groups called electron-donating groups (EDGs) and electron