Computational Evaluation of Me₂ TCCP as Lewis Acid

Area of Science:

• Supramolecular Chemistry
• Computational Chemistry
• Organic Chemistry

Background:

• Dimethyl-2,2,3,3-tetracyanocyclopropane (Me₂TCCP) is a molecule with potential for non-covalent interactions.
• Understanding the nature and strength of these interactions is crucial for designing new materials and host-guest systems.

Purpose of the Study:

• To computationally investigate the formation and stability of supramolecular adducts involving Me₂TCCP.
• To elucidate the driving forces and bonding characteristics of these complexes.

Main Methods:

• Density Functional Theory (DFT) calculations using B3LYP-D3/def2-TZVP.
• Geometry optimization, interaction energy calculations, and energy decomposition analyses.
• Atoms-in-molecules (AIM) analysis, molecular electrostatic potential (MEP) mapping, and Noncovalent Interaction (NCI) plots.

Main Results:

• Computed interaction energies and geometries for adducts of Me₂TCCP with 21 small molecules and 10 anions.
• Complexation is driven by dispersion forces with non-polar guests and orbital interactions with polar/anionic guests.
• Identified an empty hybrid σ*/π* orbital on Me₂TCCP responsible for stabilizing the most robust adducts through donor-acceptor interactions.

Conclusions:

• Me₂TCCP adducts are thermodynamically feasible, with stability comparable to or exceeding hydrogen bonding with water.
• The interaction locus is primarily at the electron-poor sp³-hybridized carbon atoms of the cyclopropane ring.
• The study provides insights into the non-covalent chemistry of Me₂TCCP, highlighting its potential in supramolecular assembly.