Control self-assembly of hydrazide-based cyclic hexamers: in or out

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Chemical Crystallography

Background:

• Noncovalent synthesis offers a pathway to complex molecular architectures.
• Controlling regioselectivity in the formation of cyclic molecules is a significant challenge.
• Hydrazide-based cyclic structures are of interest for their unique properties and potential applications.

Purpose of the Study:

• To develop a highly regioselective method for synthesizing hydrazide-based cyclic hexamers.
• To achieve precise control over the arrangement of functional units within the cyclic structures.
• To explore the impact of spacer modification on noncovalent assembly.

Main Methods:

• Modification of alkoxy group position on a spacer molecule.
• Development of an algorithmic approach for intermolecular and intramolecular hydrogen bonding.
• Analysis of reaction products to determine isomeric distribution and regioselectivity.

Main Results:

• Moving the alkoxy group from position 5 to 4 on the spacer enabled highly regioselective synthesis.
• One specific isomer out of thirteen possible cyclic hexamers was selectively formed.
• Precise control over the orientation (in or out) of two hydrazide units within the hexamer was achieved.

Conclusions:

• The strategic placement of the alkoxy group is critical for directing the regioselectivity of noncovalent synthesis.
• This method provides a robust strategy for the controlled assembly of complex hydrazide-based macrocycles.
• The findings advance the field of supramolecular chemistry by enabling predictable synthesis of specific isomers.