Question

Which behave both as a nucleophile as wcll as an clectrophile? (1) \(\mathrm{CII}_{3} \mathrm{NII}_{2}\) (2) \(\mathrm{CII}_{3} \mathrm{Cl}\) (3) \(\mathrm{CII}_{3} \mathrm{CN}\) (4) \(\mathrm{CII}_{3} \mathrm{OII}\)

Short answer

(\mathrm{CII}_{3} \mathrm{CN}\)

Step-by-step solution

- Understand the Definitions

Nucleophiles are species that donate an electron pair to an electrophile to form a chemical bond. Electrophiles are species that accept an electron pair from a nucleophile. To solve this exercise, identify which of the given compounds can act both as an electron pair donor and acceptor.

- Analyze \ (\mathrm{CII}_{3} \mathrm{NII}_{2}\)

\(\mathrm{CII}_{3} \mathrm{NII}_{2}\) contains two groups: trichloromethyl and nitro. The nitro group is typically an electron-withdrawing group, making it an effective electrophile, but it does not donate electrons effectively.

- Analyze \ (\mathrm{CII}_{3} \mathrm{Cl}\)

\(\mathrm{CII}_{3} \mathrm{Cl}\) similarly contains a trichloromethyl group and a chlorine atom, which can act as an electron-withdrawing group. However, chlorine is also a good leaving group, making this compound possible for nucleophilic involvement, but it is more often an electrophile.

- Analyze \ (\mathrm{CII}_{3} \mathrm{CN}\)

\(\mathrm{CII}_{3} \mathrm{CN}\) has a trichloromethyl group and a cyano group. The cyano group (CN) can accept electrons via its triple bond (acting as an electrophile) and also donate a lone pair of electrons on nitrogen (acting as a nucleophile). Thus, \(\mathrm{CII}_{3} \mathrm{CN}\) can act both as a nucleophile and an electrophile.

- Analyze \ (\mathrm{CII}_{3} \mathrm{OII}\)

\(\mathrm{CII}_{3} \mathrm{OII}\) consists of a trichloromethyl group and a hydroxyl group. The hydroxyl group (OH) can donate electrons, making it a nucleophile. However, it does not effectively accept an electron pair due to the electron-rich nature of oxygen.

- Conclusion

Among the given options, \(\mathrm{CII}_{3} \mathrm{CN}\) is the only compound that can act both as a nucleophile, by donating electrons from the nitrogen, and as an electrophile, by accepting electrons into the triple bond of the cyano group.

Key concepts

electron pair donor

An electron pair donor is a chemical species that has a pair of electrons available to form a bond with an electron acceptor. These are typically called nucleophiles.
Nucleophiles donate their electron pair to another atom or molecule that is deficient in electrons, known as the electrophile.

• Common electron pair donors include molecules like water \(\text{H}_2\text{O}\), ammonia \(\text{NH}_3\), and hydroxide ions \(\text{OH}^-\).
• Nucleophiles tend to have lone pairs of electrons or pi electrons that can be used in the formation of a new bond.
• It is usually seen that nucleophiles have extra electrons, making them negatively charged or neutral with at least one lone pair of electrons.

Remember, the more available the pair of electrons is, the stronger the nucleophile will be.

electron pair acceptor

An electron pair acceptor is also known as an electrophile. These species accept an electron pair from an electron pair donor to form a chemical bond. Electrophiles are typically electron-deficient.
Electrophiles can usually accept electrons due to the lack of a full electron configuration or from having regions that are positively charged.

• Typical examples include molecules like hydrogen ions (\(\text{H}^+\)), aluminum chloride (\(\text{AlCl}_3\)), and carbocations.
• Electrophiles are neutral or positively charged and have regions that can attract electron pairs.

Electrophiles must be reactive enough to readily accept electrons for a successful chemical interaction.

chemical bonding

Chemical bonding is the physical process responsible for the interactions and associations of atoms within molecules or compounds. These associations result from the forces between the atoms, such as the sharing of electron pairs between atoms.

• There are several types of chemical bonds, including ionic bonds, covalent bonds, and metallic bonds.


• Ionic bonds involve the transfer of electrons from one atom to another, typically between a metal and a non-metal. This results in the formation of ions.


• Covalent bonds involve the sharing of electron pairs between atoms, often between non-metals.


• Metallic bonds are formed when electrons are shared over many nuclei, typically within metals.

Understanding these bonds is essential for explaining the structures and properties of different chemical compounds.