Endohedrally Functionalized Heteroleptic Coordination Cages for Phosphate Ester Binding

Abstract

Metallosupramolecular hosts of nanoscopic dimensions, which are able to serve as selective receptors and catalysts, are usually composed of only one type of organic ligand, restricting diversity in terms of cavity shape and functional group decoration. We report a series of heteroleptic [Pd2A2B2] coordination cages that self‐assemble from a library of shape complementary bis‐monodentate ligands in a non‐statistical fashion. Ligands A feature an inward pointing NH function, able to engage in hydrogen bonding and amenable to being functionalized with amide and alkyl substituents. Ligands B comprise tricyclic aromatic backbones of different shape and electronic situation. The obtained heteroleptic coordination cages were investigated for their ability to bind phosphate diesters as guests. All‐atom molecular dynamics (MD) simulations in explicit solvent were conducted to understand the mechanistic relationships behind the experimentally determined guest affinities.

Molecular engineering of confined space in metal–organic cages

“…58 This approach has subsequently been utilised in the assembly of other cis-Pd 2 L 2 L 0 2 cages incorporating fluorenone-and helicene-based ligands, exhibiting circularly-polarised luminescence (CPL), 59 and systems in which endohedral carbazole N-substituents could be tuned to modulate binding of phosphate ester guests. 60 Geometric complementary between ligands has also been a successful strategy for generating higher nuclearity structures (Fig. 8(b)).…”

“…Exchanging the endohedral carbazole N-H of one ligand for a N-CH 3 group led to a dramatic decrease in the binding constant of diphenyl phosphate anions (from 2 Â 10 3 M À1 to 77 M À1 ) due to the loss of hydrogen bonding interactions between host and guest. 60 Although encapsulation is generally considered from the point of view of the impact that confinement within the host has on the guest(s), guest-binding can also affect chemical groups of the host scaffold. Clever and co-workers examined cage [Pd 2 (70) 4 ] 4+ , assembled from ditopic ligands with rotor units (Fig.…”

“…Exchanging the endohedral carbazole N–H of one ligand for a N–CH 3 group led to a dramatic decrease in the binding constant of diphenyl phosphate anions (from 2 × 10 3 M −1 to 77 M −1 ) due to the loss of hydrogen bonding interactions between host and guest. 60…”

Endohedral funktionalisierte heteroleptische Koordinationskäfige für die Bindung von Phosphatestern

“…[64] Röntgendaten können kostenlos über den CCDC-Service bezogen werden. [65] Die Autoren bedanken sich für die zur Verfügung gestellte Rechenzeit auf dem Linux-HPC-Cluster der TU Dortmund (LiDO3), der im Rahmen einer Großgeräte-Initiative von der Deutschen Forschungsgemeinschaft (DFG, Projekt 271512359) mitfinanziert wurde. Wir danken Prof. Dr. Wolf G. Hiller…”

Influence of the solvent in the self-assembly and binding properties of [1 + 1] tetra-imine bis-calix[4]pyrrole cages

“…1,2 The portals connecting the two phases and their sizes control the in and out exchange of the guests. These singular features make cage containers attractive molecular designs for different applications such as molecular recognition, [3][4][5] stabilization of reactive species 6 and mediation of chemical reactivity, 7,8 among others. [9][10][11][12] The rst examples of molecular cages date back to the middle 80s'.…”