摘要：SummarySingle-crystal X-ray diffraction (SCXRD) is a widely used method for structural characterization. Generally, low temperature is of great significance for improving the crystallographic diffraction quality. Herein we observe that this practice is not always effective for flexible metal-organic frameworks (f-MOFs). An abnormal crystallography, that is, more diffraction spots at a high angle and better resolution of diffraction data as the temperature increases in thef-MOF (1-g), is observed. XRD results reveal that1-ghas a reversible anisotropic thermal expansion behavior with a record-highc-axialpositive expansion coefficient of 1,401.8 × 10−6K−1. Calculation results indicate that the framework of1-ghas a more stable thermodynamic configuration as the temperature increases. Such configuration has lower-frequency vibration and may play a key role in promoting higher Bragg diffraction quality at room temperature. This work is of great significance for how to obtain high-quality SCXRD diffraction data.Graphical abstractDisplay OmittedHighlights•A higher diffraction quality of single crystal at a higher temperature•An MOF with reversible anisotropic thermal expansion behavior•A more stable thermodynamic configuration improves the diffraction quality of crystalMaterials science; Materials chemistry; Materials characterization; Materials structure
