Single-crystal X-ray diffraction study of a host-guest system comprising monofunctionalized-hydroxy pillar[5]arene and 1-octa-namine

Abstract

Co-crystallization of a monofunctionalized hy-droxy pillar[5]arene with 1-octa-namine resulted in the formation of an inclusion complex where the alkyl chain is threaded in the macrocycle cavity, namely 1,2,3,4-(1,4-dimeth-oxy)-5-(1-hy-droxy-4-meth-oxy)-pillar[5]arene-1-octa-namine-water (1/1/1), C₄₄H₄₈O₁₀·C₈H₁₉N·H₂O. The guest compound is stabilized inside the cavity by hydrogen-bonding and C-H⋯π inter-actions. The water mol-ecule in the asymmetric unit mediates the formation of a supra-molecular dimer by hydrogen-bonding inter-actions. These functionalized-pillararene hosts expand the possibility of exploring more supra-molecular inter-actions with various guest species.

Keywords: Functionalized pillararene; crystal structure; encapsulation; host–guest inter­action.

Figure 1

Displacement ellipsoid representation (30% probability) of Pil-OH·OctNH₂. Hydrogen atoms are omitted for clarity.

Figure 2

Hydrogen-bonding inter­actions between Pil-OH·OctNH₂ systems showing the formation of a water-mol­ecule-mediated supra­molecular dimer. [Symmetry code: (i) −x + 2, −y + 1, −z + 1.]

Figure 3

Crystal structure of the inclusion complex Pil-OH·OctNH₂ showing weak C—H⋯O and C—H⋯ π inter­actions where Cg1–4 are the centroids of the aromatic rings in the pillararene system. C—H⋯O inter­actions are represented as brown and C—H⋯ π as green dashed lines.