Search for: All records

This study explores the solution- and solid-state assembly of phenylalanine-based hypervalent iodine macrocycles (HIMs) with lithium and sodium cations. The metal cation binding of HIMs was evaluated by addition of lithium tetrakis(pentafluorophenyl)borate ethyl etherate LiBArF₂₀and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate NaBArF₂₄. The electron-rich, outwardly projected carbonyl oxygens of the HIM co-crystalize with the cations into bent supramolecular architectures. Both crystal structures show a pattern of assembly between HIM and metal cation in 2:1 ratio. While association with sodium leads to a polymer-like network, the lithium crystal structure was limited to dimeric assemblies of HIM. In the lithium-coordinating complex, the oxygen–lithium–oxygen bond angle is approximately 98.83°, displaying a closer arrangement of two HIMs. In contrast, the sodium complex exhibits a more open orientation of two HIMs with an oxygen–sodium–oxygen bond angle close to 167.98°. Lastly, a comparative study of association constants and binding energies for phenylalanine-based HIM with LiBArF₂₀and NaBArF₂₄are presented. 

A series of valine functionalized supramolecular hypervalent iodine macrocycles (HIMs) with enlarged aromatic cores, including naphthalene and anthraquinone, have been synthesized. Single crystal analysis shows the macrocycles consist of a slightly distorted cyclic planner interior with three carbonyl oxygens from the amino acid residues facing towards the center of the macrocycle and all three alkyl groups above one plane. Owing to the enlarged aromatic core, the naphthalene-based HIMs were successfully co-crystallized with Buckminsterfullerene (C60) into a long-range columnar supramolecular structure. The assembled architecture displays a long-range pattern between HIM and C60 in a 2 : 3 ratio, respectively. Disassembly of the HIMs can be accomplished by adding anions of tetrabutylammonium (TBA) salts that selectively bind with the electron deficient iodine center in HIM systems. A comparative study of the associations constants and the binding energies for different aromatic-based HIMs with TBA(Cl) and TBA(Br) is presented.