Polyfunctional Molecules

Polyfunctional Molecules


  • Polyfunctional molecules are those that contain more than one functional group.
  • The functional groups in these molecules can operate independently or together, influencing the molecule’s behaviour.

Structure and Behaviour

  • The physical properties and chemical reactivity of polyfunctional molecules are dictated by the structure and arrangement of the functional groups.
  • The functional groups within a molecule can interact, changing the molecule’s conformation or reactivity.
  • Polyfunctional organic molecules often exhibit isomerism, where molecules have the same molecular formula but a different structural formula.

Polyfunctional Molecules in Dyes

  • Many synthetic dyes are derived from polyfunctional aromatic compounds, specifically azo dyes.
  • Azo dyes possess azo functional groups (-N=N-) and aromatic rings; their colour properties are due to light absorption in the visible spectrum.
  • These compounds demonstrate both dyeing and coupling reactions, helping to create a wide range of coloured substances.
  • Coupling reactions happen when a diazonium ion reacts at a position activated by an electron-donating group to produce a coloured azo compound.

Synthesising Polyfunctional Molecules

  • Creating polyfunctional molecules involves multi-step syntheses, adding one functional group at a time.
  • This process can be complex, demanding an understanding of how functional groups react and the use of protective groups when necessary.
  • Protective groups are temporary and can be removed after the desired reactions are completed, restoring the original functional group.

Key Points for Understanding Polyfunctional Molecules

  • The nature and arrangement of functional groups impact the molecule’s physical properties and reactivity.
  • Functional groups can display a range of reactions, enabling the synthesis and application of complex molecules.
  • Unraveling the behaviour and potential uses of polyfunctional molecules requires a firm grasp of organic chemistry principles and concepts.