Ditetrel Bonding from Reactive Strained Propellane and Cyclic Carbocation as an Electron Donor/Acceptor

Area of Science:

• Computational Chemistry
• Supramolecular Chemistry
• Chemical Bonding

Background:

• Ditel bond (DTB) complexes are formed between Lewis bases like [1.1.1]propellane and Lewis acids such as cyclic carbocations.
• Understanding the stability and nature of these interactions is crucial for designing novel molecular architectures.

Purpose of the Study:

• To theoretically investigate the binary ditetrel bond (DTB) complexes between [1.1.1]propellane and cyclic carbocations.
• To analyze the factors influencing the stability of these complexes, including ring size and saturation.
• To elucidate the electronic nature of the DTB interactions using advanced computational methods.

Main Methods:

• Density functional theory (DFT) calculations using the B3LYP(D3)/def2-TZVP level of theory.
• Energy decomposition analysis (EDA) and extended transition state combined with natural orbitals for chemical valence (ETS-NOCV) for interaction analysis.
• Independent gradient model (IGM) and quantum theory of atoms in molecules (AIM) for visualizing interactions.

Main Results:

• Binary DTB complexes exhibit substantial thermodynamic stability with binding energies around -10 kcal mol⁻¹.
• Five-membered cyclic carbocation complexes are more stable than six-membered ones by 2-4 kcal mol⁻¹.
• Saturation of cyclic carbocations and substitution of [1.1.1]propellane with SiH₂ enhance complex stability.

Conclusions:

• DTB complexes possess significant thermodynamic stability, influenced by carbocation ring size and saturation.
• The electronic structure calculations confirm the presence of substantial DTB interactions.
• This work provides fundamental insights into the nature of DTB interactions, relevant for molecular design.