2025/02/06 by Claire Casaday, Cristin E. Juda, Shao‐Liang Zheng +4 · 1 voice
Chemistry · Materials Science · Physics and Astronomy · #Metal-Organic Frameworks: Synthesis and Applications #Magnetism in coordination complexes #X-ray Spectroscopy and Fluorescence Analysis
paper · doi:10.1021/acs.inorgchem.4c05423
openalex publication_date 2025/02/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/27
We analyze the effect of integrated resolution, data scaling, structural refinement, and crystal symmetry on the extracted scattering perturbations and their uncertainties for anomalous (resonant) X-ray diffraction on mixed-metal molecular clusters. We probe the metal constituency, substitutional homogeneity, and positional disorder of both biased and unbiased ligand environments. Anomalous X-ray diffraction studies were conducted on ( Ftbs L)Zn 2 Ni(py) ( 1 ), [K(C 222 )][( Ftbs L)Zn 2 Ni] ( 2 ), and [K(THF) 3 ][( Ftbs L)Zn 2 Ni(NAd)] ( 3 ). Analysis of diffraction data collected at energies along the Ni and Zn K-edges on [Zn 2 Ni] clusters reveals data resolution, and the accuracy of the structural model greatly impacts the resonant scattering factors ( f ′, f ″) and their uncertainties. Occupancy studies on all three clusters were conducted in three ways and compared: (i) using the f ′ values of each metal site refined from diffraction data collected at energies along the Ni and Zn K-edges; (ii) using the f ′ value of each metal site refined from diffraction data collected with in-house, Cu Kα radiation; and (iii) refining each metal site as a Zn/Ni disordered pair and fixing the relative Zn-to-Ni occupancies as 2:1 across the core with supporting spectroscopic evidence from scanning electron microscope energy-dispersive spectroscopy. First, we observe highly ordered structural compositions, even when statistical mixing was anticipated; and second, we discovered that in-house X-ray diffraction collection was as precise in composition determination as synchrotron sources for this study.