Crystal Engineering with Multipoint Halogen Bonding: Double Two-Point Donors and Acceptors at Work

Area of Science:

• Supramolecular chemistry
• Crystal engineering
• Materials science

Background:

• Halogen bonding is a key interaction in crystal engineering.
• Designing synthons with predictable self-assembly is crucial.
• Understanding halogen-bond donor and acceptor interactions is vital for controlling crystal structures.

Purpose of the Study:

• To investigate the use of singly or doubly bidentate halogen-bond donors with double bidentate acceptors as supramolecular synthons.
• To explore novel halogen-bonding motifs and crystal topologies.
• To understand how conformational changes influence network formation.

Main Methods:

• Synthesis and characterization of supramolecular synthons.
• Single-crystal X-ray diffraction to determine crystal structures.
• Density Functional Theory (DFT) calculations to rationalize experimental observations.

Main Results:

• Novel halogen-bonding motifs, including double two-point recognition and infinite chains/networks, were identified.
• The formation of different 1D and 2D networks was achieved by inducing conformational changes in the donors.
• DFT calculations successfully predicted and explained the observed crystal topologies and interactions.

Conclusions:

• The investigated synthons are effective in crystal engineering, leading to diverse and predictable network structures.
• Conformational flexibility of halogen-bond donors offers a route to control dimensionality in crystal networks.
• The combination of experimental and computational methods provides a robust approach for designing supramolecular materials.