Question

write the formular and names of FIVE examples of each of the following

(i) Nucleophiles

(ii) Electrophiles

(iii) Alkyl halide

(iv) leaving groups

Answer 1

1. A Nucleophile is a species which can donates an electron pair to an electrophile form a chemical bond in a reaction. Nucleophiles are generally electron rich species, with either free electron pairs, or high-electron-density pi-bonds, or both. Some examples of such species are:

Iodide Ion (I^-) , Hydroxide Ion (OH^-), Selenium Hydride (SeH^-), TriphenylPhosphine (Ph)₃P,

But-1-ene (HC=CH₂-CH₂-CH₃) (has a pi-bond)

2. An Electrophile is a positively charged or neutral species having vacant orbitals, and an affinity to electrons. Electroophiles are generally electron deficient species, with either free orbitals, or positive charge, or both. They accept electrons from nucleophiles and form bonds. Some examples of such species are:

Hydronium Ion (H₃O⁺) , Aluminium Chloride (AlCl3) (Al has vacant orbitals), Iodine (I₂), Methylium Cation (CH₃⁺), Boron Trifluoride (BF3)

3. Alkyl Halides : Alkyl halides are organic compounds of the form R-X, where R is an alkyl group, and X is F, Cl, Br, I . Some examples of these are:

4. Leaving Groups are molecular species(fragment) that depart from a bigger molecule with a pair of electrons, in case of a heterolytic bond cleavage. These leaving groups can simply beatomic groups like halogens, or molecular fragments as well. Examples of some groups are:

Fluoride(F^-) ( a good leaving group), H₂O, Methoxy (OCH₃^- ), Tosylate, Hydride Ion(H^-), BiSuplhate Ion (HSO₄)^-