Deep-Cavity Calix[4]naphth[4]arene Macrocycles: Synthesis, Conformational Features, and Solid-State Structures.

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Macrocyclic Chemistry

Background:

• Calix[n]naphth[m]arenes are a novel class of deep-cavity hybrid macrocycles.
• These macrocycles are constructed from phenol (n) and naphthalene (m) units.

Purpose of the Study:

• To expand the calix[n]naphth[m]arene family by synthesizing new derivatives.
• To investigate the synthesis, conformational analysis, spectroscopic properties, and solid-state structures of calix[4]naphth[4]arene and its permethylated analog.

Main Methods:

• Synthesis via 2 + 2 fragment coupling macrocyclization under acidic conditions.
• Solvent-controlled selective formation of the calix[4]naphth[4]arene derivative.
• X-ray crystallography for solid-state structure determination.
• Conformational analysis and spectroscopic characterization.

Main Results:

• Successful synthesis of calix[4]naphth[4]arene (C) and its permethylated analog (C).
• X-ray structure of C reveals a chair-like 1,2,3,4-alternate conformation stabilized by intramolecular hydrogen bonds.
• X-ray structure of C shows a distinct 1,3,5,7-alternate conformation.

Conclusions:

• The study successfully expands the calix[n]naphth[m]arene family with new synthesized compounds.
• The conformational diversity of these macrocycles is demonstrated through solid-state structural analysis.
• Solvent plays a critical role in the selective synthesis of specific calix[n]naphth[m]arene derivatives.