Electrophiles and nucleophilic centers

How to recognize electrophiles? : The electrophiles try to establish a bond to a nucleophilic center, ie. bearing a full or partial negative charge and having an electron pair. So they have to be - carriers of a full positive charge, eg $CH_3^+ $ - carriers of a partial positive charge, eg $ CH_2ClC = OCH_2Cl $ (charge $\delta +$ of the 2nd carbon accentuated by the $ I^-$ effects of the two chloromethyles) - bearers of an electronic gap eg $ F_3B $ or capable of easily producing such a gap, for example $ HCl \rightarrow H^+ (gap) + Cl^- $

How to evaluate the electrophilic force in aqueous solution? The electrophiles in aqueous solution are all the stronger if - for the same atom the + charge is large, eg $ NO_2^+ \gt NO^+ $ ($ NO_2^+ $ has two + charges on $ N $ because of the dative bond with $ O $ ! !) - in a row (period) of the periodic table: the pair acceptor atom is more →     electronegative , eg $ Cl^+ \gt HS^+ $. (It fixes the pair better) - in a column (family) of the periodic table: the electron pair acceptor atom is small, eg $F_2 \gt Cl_2 $ (by producing $ 2F^- $ from $ F_2 $ one electron pair is accepted) - for the same atom the →       inductive effect to this atom is more negative, eg $ CHCl_2CHO \gt CH_2ClCHO \gt CH_3CHO $ (The $ I_- $ effect removes $e^- $ which makes the carbon of the carbonyl group more positive) - for the same atom the atom carrying the gap has less steric hindrance eg $ AlCl_3 \gt AlI_3 $ ($ I $ bigger and less electronegative than $ Cl $)

How to recognize a nucleophilic center? A nucleophilic center must be able to give an electronic doublet by - bearing a full or partial negative charge, eg $ CH_3CH_2^- $ - having an electronic doublet available, eg $ CH_2 = CH_2 $ (the $ \ pi $ doublet)