Functional Groups

Functional Groups

Definition

• Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.

Importance

• Determine the properties and reactivity of organic compounds.

• Serve as the basis for classifying organic molecules.

Common Functional Groups

1. Hydroxyl Group (-OH)

• Structure: R-OH

• Properties: Polar, can form hydrogen bonds.

• Example: Alcohols (e.g., ethanol).

2. Carbonyl Group (C=O)

• Structure: R-CO-R' (ketone) or R-CHO (aldehyde)

• Properties: Polar, can participate in nucleophilic addition reactions.

• Example: Ketones (e.g., acetone), Aldehydes (e.g., formaldehyde).

3. Carboxyl Group (-COOH)

• Structure: R-COOH

• Properties: Acts as an acid (donates H+), polar.

• Example: Carboxylic acids (e.g., acetic acid).

4. Amino Group (-NH2)

• Structure: R-NH2

• Properties: Acts as a base (accepts H+), polar.

• Example: Amines (e.g., aniline).

5. Sulfhydryl Group (-SH)

• Structure: R-SH

• Properties: Can form disulfide bonds, polar.

• Example: Thiols (e.g., cysteine).

6. Phosphate Group (-PO4)

• Structure: R-PO4^2-

• Properties: Contributes negative charge, involved in energy transfer (ATP).

• Example: Nucleotides (e.g., ATP).

7. Methyl Group (-CH3)

• Structure: R-CH3

• Properties: Nonpolar, hydrophobic.

• Example: Methylated compounds (e.g., methylated DNA).

Summary of Functional Group Properties