Spatio‐Chemical Heterogeneity of Defect‐Engineered Metal–Organic Framework Crystals Revealed by Full‐Field Tomographic X‐ray Absorption Spectroscopy. (18th March 2021)

• Record Type: Journal Article
• Authors: Ferreira Sanchez, Dario; Ihli, Johannes; Zhang, Damin; Rohrbach, Thomas; Zimmermann, Patric; Lee, Jinhee; Borca, Camelia N.; Böhlen, Natascha; Grolimund, Daniel; van Bokhoven, Jeroen A.; Ranocchiari, Marco
• Is Part Of: Angewandte Chemie. Volume 133:Number 18(2021)
• Page Start: 10120
• Page End: 10127
• Publication Date: 2021-03-18
• Subjects: Composite materials -- defect engineering -- HKUST-1 -- X-ray absorption spectroscopy -- X-ray tomography; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202013422
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The introduction of structural defects in metal–organic frameworks (MOFs), often achieved through the fractional use of defective linkers, is emerging as a means to refine the properties of existing MOFs. These linkers, missing coordination fragments, create unsaturated framework nodes that may alter the properties of the MOF. A property‐targeted utilization of this approach demands an understanding of the structure of the defect‐engineered MOF. We demonstrate that full‐field X‐ray absorption near‐edge structure computed tomography can help to improve our understanding. This was demonstrated by visualizing the chemical heterogeneity found in defect‐engineered HKUST‐1 MOF crystals. A non‐uniform incorporation and zonation of the defective linker was discovered, leading to the presence of clusters of a second coordination polymer within HKUST‐1. The former is suggested to be responsible, in part, for altered MOF properties; thereby, advocating for a spatio‐chemically resolved characterization of MOFs. Abstract : A three‐dimensional view of chemical heterogeneities in defect‐engineered HKUST‐1 metal–organic framework (MOF) crystals is presented. Cryo‐full‐field XANES computed tomography was used to visualize the presence and distribution of a second coordination polymer of reduced copper coordination within defect‐engineered HKUST‐1 crystals. Observations encourage a revisitation of the structure‐property relationships of defect‐engineered MOFs.