Bimetallic Copper/Ruthenium/Osmium Complexes: Observation of Conformational Differences Between the Solution Phase and Solid State by Atomic Pair Distribution Function Analysis

• Published in: Angewandte Chemie 2022-01, Vol.134 (5), p.n/a
• Main Authors: Xie, Zhu‐Lin, Liu, Xiaolin, Valentine, Andrew J. S., Lynch, Vincent M., Tiede, David M., Li, Xiaosong, Mulfort, Karen L.
• Format: Article
• Language: English
• Subjects: Acetonitrile; Bimetals; Chemistry; Coordination compounds; Crystal structure; Distribution functions; Energy distribution; Function analysis; metal-metal interactions; Metals; Molecular modelling; Molecular structure; Osmium; pair distribution function analysis; Ruthenium; Solid state; structure elucidation; X-ray diffraction; X-ray scattering
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202111764

High‐energy X‐ray scattering and pair distribution function analysis (HEXS/PDF) is a powerful method to reveal the structure of materials lacking long‐range order, but is underutilized for molecular complexes in solution. We demonstrate the application of HEXS/PDF with 0.26 Å resolution to uncover the solution structure of five bimetallic CuI/RuII/OsII complexes. HEXS/PDF of each complex in acetonitrile solution confirms the pairwise distances in the local coordination sphere of each metal center as well as the metal⋅⋅⋅metal distances separated by over 12 Å. The metal⋅⋅⋅metal distance detected in solution is compared with that from the crystal structure and molecular models to confirm that distortions to the metal bridging ligand are unique to the solid state. This work presents the first example of observing sub‐Ångström conformational differences by direct comparison of solution phase and solid‐state structures and shows the potential for HEXS/PDF in the determination of solution structure of single molecules. The solution phase structure of five bimetallic CuI/RuII/OsII complexes was revealed by high‐energy X‐ray scattering and pair distribution function analysis (HEXS/PDF). Assisted by computational simulation, conformational differences of the complexes in the solution and solid states were identified with sub‐Ångström resolution.