Crystal structure of a hexacationic Ag(I)-pillarplex-dodecyl-diammonium pseudo-rotaxane as terephthalate salt

Abstract

A new pseudo-rotaxane, consisting of a tubular, organometallic Ag-pillarplex ring and dodecyldiammonium axle component, is introduced and investigated towards potential non-covalent interactions by Full Interaction Maps (FIMs). FIMs predict regions of probable supramolecular interactions solely at the organic ligands, namely the rim and the aromatic rings of the pillarplex. The results were compared to structural parameters experimentally obtained by single-crystal X-ray diffraction. The pseudo-rotaxane was crystallized as a hydrated terephthalate salt, and the molecular and the crystal structure are discussed. The experimentally observed interactions are quantified using Hirshfeld surface analysis. In contrast to the FIMs prediction, four different interaction modes can be experimentally observed in the solid-state: encapsulation of a guest molecule, hydrogen bonding, π- and metal interactions.

Silver and Gold Pillarplex Pseudorotaxanes from α,ω‐Dicarboxylic Acids

“…This is likely explained by the fact that the incorporated diacids are longer than the diacid encapsulated in 2 , now presenting the carboxylic groups outside the cavities. Hereby, hydrogen bonding with the rim of neighbouring pillarplex cations, which already was observed for the pillarplexes with, e. g. counter anion PF 6 − and solvent molecules, or hydrogen bonding between two neighbouring acids is enabled [24,26] . By inspecting the Hirshfeld surface analysis of 3 and 4 , mainly potential hydrogen bonding sites at the rim are observed, therefore 3 and 4 resemble hydrogen‐bonded polypseudorotaxanes [34–35] in the solid state.…”

“…Hereby, hydrogen bonding with the rim of neighbouring pillarplex cations, which already was observed for the pillarplexes with, e. g. counter anion PF 6 À and solvent molecules, or hydrogen bonding between two neighbouring acids is enabled. [24,26] By inspecting the Hirshfeld surface analysis of 3 and 4, mainly potential hydrogen bonding sites at the rim are observed, therefore 3 and 4 resemble hydrogen-bonded polypseudorotaxanes [34][35] in the solid state. These new findings, that the variation of guest molecules to encapsulate into pillarplexes can strongly influence the packing and the occurring (non-)covalent interactions, makes those mechanically-interlocked molecules interesting in the context of recently introduced hydrogen-bonded frameworks (HOFs) [36][37][38][39] and in the context of crystal engineering.…”

“…This was previously studied by the encapsulation of sterically undemanding diamino alkanes, and their host-guest complex behaviour and occurring interactions were investigated (see Figure 2B). [13,26] Based on these experiments the key factors controlling the guest encapsulation into the pillarplex cavity are hydrophobic interactions and the tubular shape of the respective cavity. The encapsulated diamino alkanes can be further converted to pillarplex [2]rotaxanes by introducing bulky stopper motifs.…”

‘Young crystallographers’ rejuvenate crystallography in Germany

“…Finally, possibly our biggest project so far was our special issue, which appeared in 2022 in the journal Zeitschrift fu ¨r Kristallographie. This issue featured contributions from young crystallographers from all over Germany on a wide variety of topics, including Theory (Subramaniam et al, 2022;Ernst et al, 2022;Nentwich et al, 2022b;Hornfeck, 2022;Wiedemann, 2022), Crystal Growth (van Terwingen et al, 2022;Weigel et al, 2022, Buyer et al, 2022, Structure Solution (Heinen et al, 2022;Folkers et al, 2022;Heidecker et al, 2022), and Properties (Ludt & Zschornak, 2022;Breternitz, 2022).…”