Isoreticular Expansion in Porous Aluminum(III) and Gallium(III) Phosphonates: Synthesis, Structure, and Properties
Year: 2026
Type: article
Abstract: We report the synthesis, structural elucidation, and establishment of structure−property relationships for two metal−organic frameworks (MOFs), [M(OH)(H2BPD)]·xH2O (M = Al3+, Ga3+, x = 11–13), denoted as M-CAU-67, employing the ditopic linker molecule N,N′-4,4′ bipiperidine bis(methylenephosphonic acid) (H4BPD). The title compounds can be synthesized on a milligram scale under hydrothermal conditions, while gram-scale synthesis was realized under reflux conditions. Single-crystal X-ray diffraction (SCXRD) revealed an isoreticular, expanded MIL-91 type structure, representing a rare case of isoreticular expansion in porous metal phosphonates. The framework structure was confirmed by Rietveld refinement against powder X-ray diffraction (PXRD) data and further validated by solid-state NMR spectroscopy (31P MAS, 27Al 3Q MAS). Solvent-exchange experiments and variable-humidity/temperature PXRD data revealed high framework flexibility. The compounds show permanent microporosity and a complex, polarity- and size-dependent sorption behavior toward gases and vapors.
Source: Chemistry of Materials
Authors: Jennifer Theissen, Marvin Radke, Sebastian Mangelsen, Elien Derveaux, Roberth Mateo Narváez Adams, Tobias Wagner, Jasper Lopau, Christian Näther, Christian Nelle, Jörn Struve, Felix Steinke, Jesús Gándara Loe, Nick Gys, Tom Hauffman, Michael Tiemann, Frederik Tielens, Peter Adriaensens, Sebastian Henke, Wouter Marchal, Rob Ameloot, Norbert Stock
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: G1121524816, Hochauflösendes RasterElektronenmikroskop mit EDX, G3837786636, G4765207058, Understanding flexibility in responsive metal-organic frameworks (MOFs) (MOFFLex), G6650912323, G7599734730, Platform for liquid and solid state Nuclear Magnetic Resonance (NMR) spectroscopy, Towards a versatile photoelectron spectroscope for in situ interfacial molecular studies in materials science
OpenAlex ID: W7172448754