Formation of an Amine-Water Cyclic Pentamer: A New Type of Water Cluster in a Polyazacryptand

Abstract

Structural analysis of an adduct of a thiophene-based cryptand with tosylic acid shows the formation of a hybrid amine-water cyclic pentamer composed of four water molecules and one protonated amine in the charged hydrophobic cavity. The bulky tosylate groups remain outside the cavity, making the ligand favorable for hosting water molecules. Ab initio calculations based on density functional theory (DFT) confirm that the hybrid amine-water pentamer is stabilized inside the hydrophobic cavity of the cryptand.

Self-assembled cyclic oligothiophene nanotubes: Electronic properties from a dispersion-corrected hybrid functional

“…Although the B3LYP hybrid functional produces accurate band gaps, it still fails completely for noncovalent interactions. [26][27][28][29][30][31][32][33][34][35][36][37][38][39] The reason for this failure is that many DFT approximations (including B3LYP) do not accurately account for correlation effects describing the instantaneous multipole/induced multipole charge fluctuations between molecular surfaces. As a result, standard B3LYP-geometry optimizations on noncovalently interacting systems can typically lead to unbound clusters and dissociation of adsorbed species.…”

Supramolecular Encapsulation of Tetrahedrally Hydrated Guests in a Tetrahedron Host

“…[9,10] Recently, an elegant example of a lone water molecule in the fullerene C 60 was reported. [11] However, such a tetrahedral array for a discrete pentamer cluster enclosed in a capsule-like host, [12,13] has not previously been observed.…”

Anion Cluster: Assembly of Dihydrogen Phosphates for the Formation of a Cyclic Anion Octamer

“…1–3 It is also a prevalent term to describe intermolecular bonding features between water molecules called a “water cluster” in which discrete water molecules are assembled through hydrogen bonding interactions forming a variety of chains or rings. 4–14 While a metal cluster is formed by sharing of delocalized electrons of metal atoms or ions, 3 in the case of a water cluster, molecules are held by intermolecular interactions between H-bond acceptors and H-bond donors (Scheme 1A). Another type of cluster known as an “anion cluster” has been reported in the literature, which consists of either a metal ion coordinated with anions such as [M(A) n ] (where A = anion) 15–21 or an anion linked with water molecules, such as [A(H 2 O) n ] − .…”