article published yes Jennifer Theissen author Marvin Radke author Sebastian Mangelsen author Elien Derveaux author Roberth Mateo Narváez Adams author Tobias Wagner author Jasper Lopau author Christian Näther author Christian Nelle author Jörn Struve author Felix Steinke author Jesús Gándara Loe author Nick Gys author Tom Hauffman author Michael Tiemann author 235470000-0003-1711-2722 Frederik Tielens author Peter Adriaensens author Sebastian Henke author Wouter Marchal author Rob Ameloot author Norbert Stock author 35 department 2 department 307 department 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. American Chemical Society (ACS)2026 eng 0897-4756 1520-500210.1021/acs.chemmater.6c01336 38168463-8475 @article{Theissen_Radke_Mangelsen_Derveaux_Narváez Adams_Wagner_Lopau_Näther_Nelle_Struve_et al._2026, title={Isoreticular Expansion in Porous Aluminum(III) andGallium(III) Phosphonates: Synthesis, Structure, and Properties}, volume={38}, DOI={<a href="https://doi.org/10.1021/acs.chemmater.6c01336">10.1021/acs.chemmater.6c01336</a>}, number={16}, journal={Chemistry of Materials}, publisher={American Chemical Society (ACS)}, author={Theissen, Jennifer and Radke, Marvin and Mangelsen, Sebastian and Derveaux, Elien and Narváez Adams, Roberth Mateo and Wagner, Tobias and Lopau, Jasper and Näther, Christian and Nelle, Christian and Struve, Jörn and et al.}, year={2026}, pages={8463–8475} } Theissen J, Radke M, Mangelsen S, et al. Isoreticular Expansion in Porous Aluminum(III) andGallium(III) Phosphonates: Synthesis, Structure, and Properties. <i>Chemistry of Materials</i>. 2026;38(16):8463-8475. doi:<a href="https://doi.org/10.1021/acs.chemmater.6c01336">10.1021/acs.chemmater.6c01336</a> Theissen, Jennifer, et al. “Isoreticular Expansion in Porous Aluminum(III) AndGallium(III) Phosphonates: Synthesis, Structure, and Properties.” <i>Chemistry of Materials</i>, vol. 38, no. 16, American Chemical Society (ACS), 2026, pp. 8463–75, doi:<a href="https://doi.org/10.1021/acs.chemmater.6c01336">10.1021/acs.chemmater.6c01336</a>. Theissen, Jennifer, Marvin Radke, Sebastian Mangelsen, Elien Derveaux, Roberth Mateo Narváez Adams, Tobias Wagner, Jasper Lopau, et al. “Isoreticular Expansion in Porous Aluminum(III) AndGallium(III) Phosphonates: Synthesis, Structure, and Properties.” <i>Chemistry of Materials</i> 38, no. 16 (2026): 8463–75. <a href="https://doi.org/10.1021/acs.chemmater.6c01336">https://doi.org/10.1021/acs.chemmater.6c01336</a>. J. Theissen, M. Radke, S. Mangelsen, E. Derveaux, R.M. Narváez Adams, T. Wagner, J. Lopau, C. Näther, C. Nelle, J. Struve, F. Steinke, J. Gándara Loe, N. Gys, T. Hauffman, M. Tiemann, F. Tielens, P. Adriaensens, S. Henke, W. Marchal, R. Ameloot, N. Stock, Chemistry of Materials 38 (2026) 8463–8475. J. Theissen <i>et al.</i>, “Isoreticular Expansion in Porous Aluminum(III) andGallium(III) Phosphonates: Synthesis, Structure, and Properties,” <i>Chemistry of Materials</i>, vol. 38, no. 16, pp. 8463–8475, 2026, doi: <a href="https://doi.org/10.1021/acs.chemmater.6c01336">10.1021/acs.chemmater.6c01336</a>. Theissen, J., Radke, M., Mangelsen, S., Derveaux, E., Narváez Adams, R. M., Wagner, T., Lopau, J., Näther, C., Nelle, C., Struve, J., Steinke, F., Gándara Loe, J., Gys, N., Hauffman, T., Tiemann, M., Tielens, F., Adriaensens, P., Henke, S., Marchal, W., … Stock, N. (2026). Isoreticular Expansion in Porous Aluminum(III) andGallium(III) Phosphonates: Synthesis, Structure, and Properties. <i>Chemistry of Materials</i>, <i>38</i>(16), 8463–8475. <a href="https://doi.org/10.1021/acs.chemmater.6c01336">https://doi.org/10.1021/acs.chemmater.6c01336</a> 673272026-10-01T14:16:40Z2026-10-01T14:20:02Z