B-Hπ: a nonclassical hydrogen bond or dispersion contact?

Area of Science:

• Inorganic Chemistry
• Computational Chemistry
• Supramolecular Chemistry

Background:

• Recent crystallographic studies reported B-Hπ contacts in iridium-dithiolene-phosphine complexes with boron hydride clusters.
• These contacts were initially interpreted as a novel, electrostatically driven, nonclassical hydrogen bond.

Purpose of the Study:

• To critically re-examine the nature of B-Hπ interactions using advanced quantum chemical methods.
• To challenge the electrostatic explanation and provide a more accurate characterization of these noncovalent interactions.

Main Methods:

• Application of state-of-the-art quantum chemical calculations.
• Detailed analysis of electronic structure and interaction energies.

Main Results:

• The study disproves the claimed attractive electrostatic nature of B-Hπ contacts.
• Evidence indicates these interactions are primarily driven by nonspecific dispersion forces.
• The observed B-Hπ contacts are not a novel type of hydrogen bonding.

Conclusions:

• The interpretation of B-Hπ contacts as a new hydrogen bond type is incorrect.
• B-Hπ interactions represent a nonspecific, dispersion-driven contact.
• This work clarifies the fundamental nature of noncovalent interactions involving boron hydrides.