Affiliation:
1. Department of Natural Drugs, Faculty of Pharmacy Masaryk University Palackého 1946/1 CZ-61200 Brno Czechia
2. Department of Chemistry, Faculty of Science Masaryk University Kamenice 5 CZ-62500 Brno Czechia
3. CEITEC—Central European Institute of Technology Masaryk University Kamenice 5 CZ-62500 Brno Czechia
4. Department of Chemistry University of Jyvaskyla P. O. Box 35 FI-40014 Jyväskylä Finland
5. Institute of Physics University of Tartu W. Ostwald Street 1 50411 Tartu Estonia
Abstract
AbstractNature uses various chiral and unsymmetric building blocks to form substantial and complex supramolecular assemblies. In contrast, the majority of organic ligands used in metallosupramolecular chemistry are symmetric and achiral. Here we extend the group of unsymmetric chiral bile acids used as a scaffold for organic bispyridyl ligands by employing chenodeoxycholic acid (CDCA), an epimer of the previously used ursodeoxycholic acid (UDCA). The epimerism, flexibility, and bulkiness of the ligands leads to large structural differences in coordination products upon reaction with Pd(NO3)2. The UDCA‐bispyridyl ligand self‐assembles quantitatively into a single crown‐like Pd3L6 complex, whereas the CDCA ligand provides a mixture of coordination complexes of general formula PdnL2n, i.e., Pd2L4, Pd3L6, Pd4L8, Pd5L10, and even Pd6L12 containing an impressive 120 chiral centers. The coordination products were studied by a combination of analytical methods, with ion‐mobility mass spectrometry (IM‐MS) providing valuable details on their structure and allowed an effective separation of m/z 1461 to individual signals according to the arrival time distribution, thereby revealing four different ions of [Pd3L6(NO3)3]3+, [Pd4L8(NO3)4]4+, [Pd5L10(NO3)5]5+, and [Pd6L12(NO3)6]6+. The structures of all the complexes were modelled using DFT calculations. Finally, the challenges and conclusions in determining the specific structural identity of these unsymmetric species are discussed.
Funder
H2020 Marie Skłodowska-Curie Actions
Grantová Agentura České Republiky
Ministerstvo Školství, Mládeže a Tělovýchovy
Interreg
Eesti Teadusagentuur