Chemistry of Metal-organic Frameworks Monitored by Advanced X-ray Diffraction and Scattering Techniques

Abstract

In the memory of Janez (Janko) Jamnik. AbstractThe research on metal-organic frameworks (MOFs) experienced rapid progress in recent years due to their structure diversity and wide range of application opportunities. Continuous progress of X-ray and neutron diffraction methods enables more and more detailed insight into MOF's structural features and significantly contributes to the understanding of their chemistry. Improved instrumentation and data processing in high-resolution X-ray diffraction methods enables the determination of new complex MOF crystal structures in powdered form. By the use of neutron diffraction techniques, a lot of knowledge about the interaction of guest molecules with crystalline framework has been gained in the past few years. Moreover, in-situ time-resolved studies by various diffraction and scattering techniques provided comprehensive information about crystallization kinetics, crystal growth mechanism and structural dynamics triggered by external physical or chemical stimuli. The review emphasizes most relevant advanced structural studies of MOFs based on powder X-ray and neutron scattering.

Structure determination of organic compounds by a fit to the pair distribution function from scratch without prior indexing

“…Recently, there has been growing interest in the knowledge of the local structure. The local structure may deviate from the average crystal structure (Aksel et al, 2013), especially for complex materials such as pharmaceuticals (Moore et al, 2009;Terban et al, 2020), metal-organic frameworks (Mazaj et al, 2016), organic pigments (Hunger & Schmidt, 2018;Schlesinger et al, 2020), catalysts or magnetic materials, such as semiconductors (Frandsen et al, 2016). Disorder, lattice defects or surface effects result in a local structure which differs from the average structure found by classical structure determination methods (Proffen et al, 2003;Young & Goodwin, 2011).…”

Comparison and evaluation of pair distribution functions, using a similarity measure based on cross-correlation functions

“…The analysis of the atomic pair distribution function (PDF) is the method of choice to investigate amorphous or nanocrystalline samples, as frequently found in nature (Poulain et al, 2019) and in novel, complex, engineered materials (Cliffe et al, 2010;Young & Goodwin, 2011;Zobel et al, 2015;Roeser et al, 2017;Usher et al, 2018;Billinge, 2019), e.g. metal-organic frameworks (Bennett & Cheetham, 2014;Mazaj et al, 2016;Castillo-Blas et al, 2020), glasses and pharmaceuticals (Moore et al, 2009;Nollenberger et al, 2009;Thakral et al, 2016;Shi et al, 2017).…”

Nuclear Magnetic Resonance Spectroscopy for In Situ Monitoring of Porous Materials Formation under Hydrothermal Conditions

“…Moreover, it is a multiparameter synthesis depending on various physical and chemical factors like temperature, ageing time, pressure, pH, molar composition, concentration, solvent, etc. Nevertheless, extensive studies have been carried out, and some general concepts about crystallization mechanisms of these materials have been proposed including solution-mediated nucleation-growth processes and solid-solid transformation models [8,16,18,19,20,21,22]. Nucleation and growth from soluble prefabricated SBUs or related molecular structures is among the most accepted mechanisms [8,23,24], although more elementary mechanisms like growing from monomers and small oligomers have also been suggested in the literature [25,26].…”