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18 Ιουν 2012 · What are the factors that make a good nucleophile? For our purposes, there are at least four key factors contributing to nucleophilicity. Charge. Electronegativity. Solvent. Steric hindrance. The first two should hopefully be familiar from the discussion of what makes something a strong base.
In addition, we must discuss how the nature of the electrophilic carbon, and more specifically the stability of a potential carbocationic intermediate, influences the S N 1 vs. S N 2 character of a nucleophilic substitution reaction.
Nucleophilic aromatic substitution occurs only if the aromatic ring has an electron-withdrawing substituent in a position ortho or para to the leaving group to stabilize the anion intermediate through resonance (Figure 16.19). A meta substituent offers no such resonance stabilization.
20 Αυγ 2018 · In Nucleophilic Aromatic Substitution, an electron-poor aromatic ring is attacked by a nucleophile, resulting in a substitution reaction. The reaction proceeds through a negatively charged (carbanion) intermediate. The reaction is accelerated by the presence of electron-withdrawing groups on the aromatic ring.
Reductants are then nucleophiles that give one or two electrons to an oxidant, without forming an adduct. ... and how some planar aromatic compounds, ... Koppenol WH. Nitric oxide, superoxide, and peroxynitrite: the good, the bad, and ugly. The American journal of physiology. 1996;271:C1424–1437. doi: 10.1152/ajpcell.1996.271.5.C1424.
In addition, water, alcohols and thiols are nucleophilic, because they all have lone pairs that could be donated to an electrophile. Nitrogen also has a lone pair in most compounds. That means amines are good nucleophiles, too. Carbon does not normally have a lone pair, unless it is a carbanion.
12 Σεπ 2022 · First, let's take a look at the structural representations which distinguish aromatic compounds from those that aren't aromatic. The most commonly encountered aromatic compound is benzene. The usual structural representation for benzene is a six carbon ring (represented by a hexagon) which includes three double bonds.
