(couleur) grey (Grande-Bretagne) , gray (USA) il fait gris it's a dull day, it's a grey day. faire grise mine to look morose. faire grise mine Ã  qn to give sb a cool reception.
In electrophilic aromatic substitution, the benzene ring acts as an electron donor (Lewis base or nucleophile) and reacts with an electron acceptor (Lewis acid or electrophile). The result of electrophilic aromatic substitution reactions is that an aromatic hydrogen is replaced by some other atom or functional group.
Accordingly, electron withdrawing groups are represented at low chemical shifts. Electron withdrawing groups pull electrons away from a reacting center. This can stabilize an electron rich carbanion. Some examples of electron withdrawing groups are halogens (-Cl, -F) and carboxylic acid (-COOH).