Polymorphism of L-Tryptophan: data

A new polymorph of L‑tryptophan has been prepared by crystallization from the gas phase, with structure determination carried out directly from powder XRD data augmented by periodic DFT-D calculations. The new polymorph (denoted β) and the previously reported polymorph (denoted α) are both based on alternating hydrophilic and hydrophobic layers, but with substantially different hydrogen-bonding arrangements. The β polymorph exhibits the energetically favourable L2-L2 hydrogen-bonding arrangement, which is unprecedented for amino acids with aromatic side-chains; the specific molecular conformations adopted in the β polymorph facilitate this hydrogen-bonding scheme while avoiding steric conflict of the side-chains.
Data presented is the powder XRD on the new polymorph over a range of temperatures, NMR data on the new polymorph and results from DFT-D calculations of the stabilities of the two forms.

Researhc results based upon these data are published at https://doi.org/10.1002/anie.201908247

本研究通过气相结晶法制备得到一种全新的L-色氨酸（L‑tryptophan）多晶型，其晶体结构直接通过粉末X射线衍射（powder XRD）数据结合周期性密度泛函-色散校正（DFT-D）计算完成解析。
该新型多晶型（标记为β）与已报道的α型多晶型均由交替排布的亲水层与疏水层构成，但二者的氢键排布方式存在显著差异。β型多晶型呈现出能量上更优的L2-L2氢键排布模式，该模式在带有芳香侧链的氨基酸中尚属首次报道；β型多晶型所采用的特定分子构象既适配了该氢键排布方案，又避免了侧链间的空间位阻冲突。
本数据集包含该新型多晶型在一系列温度下的粉末X射线衍射数据、其核磁共振（NMR）数据，以及两种多晶型稳定性的DFT-D计算结果。
基于本数据集的研究成果已发表于https://doi.org/10.1002/anie.201908247