Redetermination of l-tryptophan hydro-bromide

Area of Science:

• Crystallography
• Chemical Physics
• Materials Science

Background:

• The crystal structure of C(11)H(13)N(2)O(2) (+)·Br(-) was previously determined at 176 K.
• Higher precision structural data can reveal subtle intermolecular interactions and packing motifs.

Purpose of the Study:

• To redetermine the crystal structure of C(11)H(13)N(2)O(2) (+)·Br(-) with enhanced precision.
• To analyze the intermolecular interactions, including hydrogen bonding and electrostatic interactions, within the crystal lattice.

Main Methods:

• Single-crystal X-ray diffraction data collection at 100 K.
• Precise structural refinement using crystallographic data.
• Analysis of hydrogen bonding (N-H⋯Br, O-H⋯Br) and electrostatic interactions (N-H⋯C).

Main Results:

• The crystal structure was determined with significantly higher precision at 100 K compared to previous 176 K data.
• The carboxyl group and indole ring system exhibit planarity.
• Molecules are arranged in double layers stabilized by extensive N-H⋯Br and O-H⋯Br hydrogen bonds.
• Non-polar layers feature indole rings linked by electrostatic N-H⋯C interactions.

Conclusions:

• The precise crystal structure reveals detailed information about intermolecular forces governing molecular packing.
• The study highlights the importance of low-temperature data collection for accurate structural determination.
• Understanding these interactions is crucial for predicting material properties and designing new crystalline materials.