Self-assembled conjoined-cages

Abstract

A self-assembled coordination cage usually possesses one well-defined three-dimensional (3D) cavity whereas infinite number of 3D-cavities are crafted in a designer metal-organic framework. Construction of a discrete coordination cage possessing multiple number of 3Dcavities is a challenging task. Here we report the peripheral decoration of a trinuclear [Pd 3 L 6 ] core with one, two and three units of a [Pd 2 L 4 ] entity for the preparation of multi-3D-cavity conjoined-cages of [Pd 4 (L a) 2 (L b) 4 ], [Pd 5 (L b) 4 (L c) 2 ] and [Pd 6 (L c) 6 ] formulations, respectively. Formation of the tetranuclear and pentanuclear complexes is attributed to the favorable integrative self-sorting of the participating components. Cage-fusion reactions and ligand-displacement-induced cage-to-cage transformation reactions are carried out using appropriately chosen ligand components and cages prepared in this work. The smaller [Pd 2 L 4 ] cavity selectively binds one unit of NO 3 − , F − , Cl − or Br − while the larger [Pd 3 L 6 ] cavity accommodates up to four DMSO molecules. Designing aspects of our conjoined-cages possess enough potential to inspire construction of exotic molecular architectures.

Directional asymmetry over multiple length scales in reticular porous materials

“…3 Schematic representation of the different techniques reported in the literatures to impart directional asymmetry at the nanos cale in metal-organic cages using (a) similar coordination environment of metal complex and imine bond formations, 24 (b and c) steric repulsion via endo 25 and exo 26 functionalized ligands respectively, (d) geometry complementarity between ligands with different bend angles, 28 (e) guest template induced reorganization of homoleptic cages, 32 and (f) conjoined cage based on tridentate ligands with asymmetric coordination sites in the backbone ligands. 39 The asymmetric pore configuration is shown via spheres of different colours occupying the void spaces of the structure. 32 Indeed, the guest molecule induced reorganization of the initial cages into a more stable thermodynamic asymmetric product due to efficient host-guest aromatic-aromatic interactions (Fig.…”

Backbone‐Bridging Promotes Diversity in Heteroleptic Cages

“…[23] Very recently, Chand reported a series of novel conjoined-cages with multiple, non-uniform cavities by the peripheral decoration of a trinuclear [Pd3L6] core with one, two and three units of a [Pd2L4] entity. [24] Herein, we report on the assembly of a family of heteroleptic multi-cavity cages by combination of the shape-complementarity strategy with covalent bridging of two ligands in a back-to-back fashion. [25] First, we show that the combination of banana-shaped carbazole-based ligand L A with fluorene-derived ligand L B forms a new heteroleptic, cis-configured [Pd2L A 2L B 2] cage C (Supporting Information, Figures S5-11).…”

“…As such structures allow for differentiating guest species, for example, for the realization of cooperative heterotropic receptors, stimuli‐responsive catalysts and logic gates, there is growing interest in the field to allow their rational construction [23] . Very recently, Chand reported a series of novel conjoined‐cages with multiple, non‐uniform cavities by the peripheral decoration of a trinuclear [Pd 3 L 6 ] core with one, two, and three units of a [Pd 2 L 4 ] entity [24] …”

Rückgrat‐verknüpfte Liganden erhöhen die Vielfalt in heteroleptischen Koordinationskäfigen

“…B. im Rahmen kooperativ‐heterotroper Rezeptoren, stimuli‐responsiver Katalysatoren und logischer Gatter, besteht ein wachsendes Interesse an deren Konstruktion [23] . Erst kürzlich berichtete Chand über eine Reihe neuartiger “Conjoined‐Cages” mit mehreren, unterschiedlich großen Hohlräumen durch die periphere Dekoration einer zentralen, dreikernigen [Pd 3 L 6 ]‐Einheit mit einem, zwei und drei [Pd 2 L 4 ]‐Substituenten [24] …”

“…[23] Erst kürzlich berichtete Chand über eine Reihe neuartiger "Conjoined-Cages" mit mehreren, unterschiedlich großen Hohlräumen durch die periphere Dekoration einer zentralen, dreikernigen [Pd 3 L 6 ]-Einheit mit einem, zwei und drei [Pd 2 L 4 ]-Substituenten. [24] Hier berichten wir über den Aufbau einer Familie von heteroleptischen Multikavität-Systemen durch Kombination von Formkomplementarität mit kovalenter Rücken-zu-Rücken-Verbrückung zweier Liganden. [25] Zunächst zeigen wir, dass die Kombination des bananenfçrmigen, Carbazolbasierten Liganden L A mit dem vom Fluoren abgeleiteten Liganden L B einen neuen, heteroleptischen, cis-konfigurier-…”