Hydrogen-bond patterns in the congruent complex 4-nitrophenol-acetamide (1/1)

Area of Science:

• Crystal Engineering
• Supramolecular Chemistry
• Organic Chemistry

Background:

• Crystalline complexes offer insights into molecular interactions.
• Hydrogen bonding plays a crucial role in crystal structure determination.
• Nitrophenol-amide interactions are not fully understood.

Purpose of the Study:

• To synthesize and characterize a new complex formed from 4-nitrophenol and acetamide.
• To investigate the structural features and hydrogen bonding in the complex.
• To compare the complexation behavior of different nitrophenol isomers with acetamide.

Main Methods:

• Co-crystallization via fusion of 4-nitrophenol and acetamide in a 1:1 molar ratio.
• Characterization of the resulting complex (C6H5NO3.C2H5NO) using melting point determination and recrystallization.
• Structural analysis employing graph set analysis to elucidate hydrogen bonding networks.

Main Results:

• A stable, covalently bonded complex (III) with a high melting point (371.9-372.9 K) was successfully synthesized.
• The complex exhibits eutectic behavior with both acetamide and 4-nitrophenol.
• Graph set analysis revealed preserved structural motifs from the parent compounds and the formation of new, higher-order hydrogen-bonded structures, including large rings and helical chains, involving the nitro group.

Conclusions:

• The fusion of 4-nitrophenol and acetamide yields a unique, stable supramolecular complex.
• The crystal structure of the complex demonstrates a combination of preserved and novel hydrogen bonding interactions.
• The study highlights the importance of positional isomerism in nitrophenols for complex formation and structural diversity.