What are some examples of nucleophiles and strong bases?

1 Answer
Jan 13, 2015

With a few exceptions, a strong nucleophile is also a strong base.

All nucleophiles are Brønsted bases — they donate a pair of electrons to form a bond to another atom.

If they bond to a hydrogen atom, we call them bases. If they bond to any other atom (especially carbon), we call them nucleophiles.

Strong Bases/Strong Nucleophiles

A good base is usually a good nucleophile. So, strong bases — substances with negatively charged O, N, and C atoms — are strong nucleophiles.

Examples are: RO⁻, OH⁻, RLi, RC≡C:⁻, and NH₂⁻.

Strong Bases/Poor Nucleophiles

Some strong bases are poor nucleophiles because of steric hindrance.

Examples are t-BuO⁻, t-BuLi, and LiN[CH(CH₃)₂]

Weak Bases/Good Nucleophiles

I⁻ is a weak base, but it is a good nucleophile because the large electron cloud is highly polarizable.