Engineering Crystals Using sp³ -C Centred Tetrel Bonding Interactions.

Area of Science:

• Crystal Engineering
• Supramolecular Chemistry
• Organic Chemistry

Background:

• Tetrel bonding is an important non-covalent interaction.
• Exploring novel tetrel bond donors is crucial for advancing crystal engineering.
• Cyclopropane derivatives offer unique structural motifs for chemical studies.

Purpose of the Study:

• To design and synthesize novel 1,1,2,2-tetracyanocyclopropane derivatives.
• To investigate the utility of sp3-C centered tetrel bonding interactions.
• To understand the role of these interactions in crystal engineering and molecular recognition.

Main Methods:

• Synthesis of 1,1,2,2-tetracyanocyclopropane derivatives 1 and 2.
• X-ray crystallography to analyze crystal packing and intermolecular interactions.
• Density Functional Theory (DFT) calculations to determine interaction energies.

Main Results:

• Crystal structures reveal dominant sp3-C(CN)2···O interactions in derivatives 1 and 2 and their cocrystals.
• DFT calculations show significant interaction energies up to -11.0 kcal/mol.
• Cocrystal studies indicate a preference for oxygen over sulfur in interactions with the cyclopropane synthon.

Conclusions:

• The electropositive C2(CN)4 pocket acts as a directional tetrel-bond donor.
• These findings have implications for crystal engineering, supramolecular chemistry, and medicinal chemistry.
• Novel tetrel bond donors can be designed using sp3-hybridized carbon centers.