Intermolecular Hydrogen Bonding between Water and Pyrazine.

Area of Science:

• Physical Chemistry
• Molecular Spectroscopy
• Supramolecular Chemistry

Background:

• Hydrogen bonding is crucial in molecular interactions.
• Understanding non-covalent interactions in aromatic systems is key.
• Previous studies on benzene-water complexes offer a comparison.

Purpose of the Study:

• To investigate the structure of the pyrazine-water complex.
• To determine the nature of the hydrogen bond in this complex.
• To compare the bonding in pyrazine-water with benzene-water.

Main Methods:

• Supersonic expansion for complex formation.
• Rotational spectroscopy for structural analysis.
• Computational modeling to support experimental findings.

Main Results:

• The pyrazine-water complex adopts a completely planar geometry.
• Water molecule lies within the plane of the pyrazine ring.
• The hydrogen bond involves the nitrogen lone pair of pyrazine, not its pi system.

Conclusions:

• The pyrazine-water complex exhibits unique hydrogen bonding compared to benzene-water.
• The lone pair on the nitrogen atom is the primary hydrogen bond acceptor.
• The planar structure and specific bonding highlight the versatility of aromatic interactions.