Question

The N,N,N-trimethylammonium group, -N(CH3)3*, is one of the few substituents on a benzene ring that is a deactivating, meta-directing group, yet has no electron-withdrawing resonance effect. Explain.

Answer 1

we make sesona ting shuctwe tor NIN,N- toimetky Ommonium guoup -NCH) with positive chauge at e thur thu we get mot possible the paua pentavalent Niteogun , which is So how is thu-NEHs) is a Ostho or Mela directing uop Aelually this guout is not meta direching bud it inductively dleactivatei Adomatic ing the entire 9vtidh To Explain th elechoplilic Substitudion padtern observed with 2 any, auomatic system we most both resonanu ond Inductive eHect Considex fesonana etteds erls NO Tesonan u stouctue 5 bonds to nibogen O Resonancu stuctuu with au n't allowed Thuubore resonan co ettec ts au not inrolued inexplain- ing the reactivity ot this guout towauds electro plubc auoma tie Substitutien Inductve efbects - Nuy)s steongly withdaco electron density teom the ortho pasiten sina

is closest to the positively chauged mihogen most deactivated Fnd tuis makes ortho positon the Induchve ehhecd decreases with distanu, so we would expect the meta positien to also be deachrated bu Finally we would still expect Some deachivation at paua positon jess than opthhold obiano Paua> mda Ortho tor Blecophil reactivity order Fos e. g News NO2 HNO31H2S04 288 K Nu bonu of daup af 2hNo