Water Trapping of Metal–Organic Cages with Endohedral Variation

Abstract

A series of lantern-shaped M 2 L 4 metal−organic cages was synthesized by coordination-driven self-assembly of palladium(II) centers with aromatic amide bidentate ligands, and their crystal structures were investigated. Amide-functionalized ligands provide the complex with polar internal environment and the ability to encapsulate water. Tuning the size of the internal substituent allows to adjust the conformation of the ligand as well as to operate the pattern of counter-anions via steric effect and, further, to influence the arrangement of the encapsulated water guests. Contrary to expectations, the cage decorated with fluorine atoms only encapsulates two water molecules, whereas the cage substituted with larger methoxy groups can bind six water molecules with a chair arrangement. The enlarged capacity was attributed to the extrusion of two nitrate counter-anions from the cavity.

Neighboring Cage Participation for Assisted Construction of Self-Assembled Multicavity Conjoined Cages and Augmented Guest Binding

“…The host cavity 1a (or 1b ) has eight polarized C–H protons, from four strands of bound ligands, designated as a 1 (inner α-pyridyl) that are suitable for hydrogen bonding with electron-rich guest molecules. , The amide protons (NH) and carbonyl oxygens of amides (CO) present in the ligand backbone are also good hydrogen-bond donors and acceptors, respectively. − A potential guest pyrazine- N,N’ -dioxide (PZDO, G2 ) shown in Figure is also a proper fit for the [Pd 2 ( L1 ) 4 ] 4+ cage (Figure S91). Though PZDO is neutral, it can act as a pseudo anion owing to the polarity difference between N and O .…”

Self-assembly of a water-soluble endohedrally functionalized coordination cage including polar guests

“…of Pd(NO3)2 provoked the appearance of a new set of sharp signals that were diagnostic of the assembly of the 6[2•Pd] 6+ CC complex (Figure S44). We assumed the coinclusion of one molecule of water 46 with 6 took place. The putative [6•H2O][2•Pd] 6+ CC complex (Figure S88) was assembled only to a 30% extent.…”

MGOS: A Library for Molecular Geometry and its Operating System

“…The use of such resolution-dependent approaches is common despite their unreliable, inconsistent, and sometimes conflicting results [21]. We observe that VOIDOO is still popular in diverse disciplines [22,23,24,25,26,27,28,29,30,31,32] and studies of grid-based algorithms continues [33]. The absence of an overarching analytical theory is because individual researchers have focused on problem-specific, local aspects of geometry problems, concentrating on isolated issues such as surfaces, voids, channels, volumes, areas, and so on.…”