X-ray studies of conformation: observation of conformational polymorphism of a glycoluril clipElectronic supplementary information (ESI) available: Preparation and characterization of 1, crystallographic data and refinement details, 1H NMR and 13C NMR spectra and NMR studies. Computational methods. CCDC 1032703-1032707. For ESI and crystallographic data in CIF, See DOI: 10.1039/c5ce00066a

• Main Authors: Wang, Jungang, Gao, Yang, Xiang, Jiachen, Wang, Miao, Wu, Anxin
• Format: Article
• Language: English
• ISSN: 1466-8033
• DOI: 10.1039/c5ce00066a

In order to study the conformational behavior of a glycoluril clip, compound 1 was synthesized and X-ray crystallography, NMR spectroscopy, and molecular modeling were used in the work. The results of the computational studies revealed the stability of the four conformers retained the order aa > as sa > ss in both gas and solvation models, while solvation decreased the relative energies of each conformer dramatically. In the solid phase, X-ray crystallographic analysis indicated that compound 1 presented conformational polymorphism when it crystallized in various solvents. We fortunately obtained a single crystal of the aa and as conformers of the same glycoluril clip. The X-ray crystallographic analysis in this report provides the first crystallographic evidence of the conformers of a glycoluril clip. Unlike in the solid state, the conformers interconvert rapidly in solution and therefore cannot be detected on the NMR timescale. In this report, molecular modeling, X-ray crystallography and NMR spectroscopy were used to study the conformational behavior of a novel glycoluril based clip.