Protonated alcohols are examples of complete charge-shift bonds

Area of Science:

• Computational Chemistry
• Organic Chemistry
• Chemical Bonding Theory

Background:

• Traditional chemical bonding models primarily describe covalent and ionic interactions.
• Charge-shift bonds, characterized by resonance between covalent and ionic structures, were previously identified mainly in inorganic or exotic organic compounds.
• The prevalence and nature of charge-shift bonding in common organic molecules remained largely unexplored.

Purpose of the Study:

• To investigate the electronic structure and bonding characteristics of protonated aliphatic alcohols.
• To determine if charge-shift bonding occurs in common organic species.
• To elucidate the bonding mechanism in protonated alcohols using accurate theoretical calculations.

Main Methods:

• Performed accurate gas-phase and solution-phase valence bond (VB) calculations.
• Analyzed the electronic structure and bonding nature of the carbon-oxygen (C-O) bond in protonated aliphatic alcohols.

Main Results:

• Protonation of the hydroxyl group in aliphatic alcohols transforms the C-O bond.
• The transformed C-O bond exhibits characteristics of a complete charge-shift bond with significant 'no-bond' character.
• Bonding in these systems arises from resonance between covalent and ionic structures, distinct from traditional covalent bonding.

Conclusions:

• Charge-shift bonds are demonstrated to occur in common organic species, specifically protonated aliphatic alcohols.
• This finding expands the known scope of charge-shift bonding beyond inorganic and exotic organic compounds.
• The study reveals a novel bonding mechanism in frequently encountered organic molecules.