Reversible Assembly of a Supramolecular Cage Linked by Boron–Nitrogen Dative Bonds

Abstract

Boron-nitrogen dative bonds provide a suitable motif for reversible, yet strong and directed interactions, leading to the highly efficient self-assembly of small organic building blocks into supramolecular cage structures. A bipyramidal [2+3] assembly, as the first example of a supramolecular cage mediated by BN dative bonds that exists as a discrete species in solution, is quantitatively obtained from a tribenzotriquinacene-based trisboronate ester and 1,4-diazabicyclo[2.2.2]octane. Thermodynamic equilibria of cage formation are investigated by isothermal titration calorimetry and fully reversible cage opening can be observed at elevated temperatures.

Boron–Nitrogen Double Tweezers Comprising Arylboronic Esters and Diamines: Self‐Assembly in Solution and Adaptability as Hosts for Aromatic Guests in the Solid State

“…The Severin group also examined the association of 1,2‐di(4‐pyridyl)ethylene (DPE) with boronic ester E1 obtaining K 1 =1.3 × 10 4 M −1 and K 2 =3.2×10 2 M −1 for stepwise 1 : 1 and 2 : 1 complexes, respectively (Scheme ). Compound E1 was also combined with 1,4‐diazabicyclo[2.2.2]octane (DABCO) in CDCl 3 by Dhara and Beuerle, with stepwise binding constants of K 1 =1.5×10 5 M −1 and K 2 =1.2×10 2 M −1 …”

Topological landscapes of porous organic cages

“…However, the topologies we discuss can still be used to describe the underlying connectivity in a multicomponent system and indeed, multiple components may be an attractive design approach for the synthesis of some of the lower symmetry topologies. Several examples of multiple component systems, [52][53][54][55] including those with orthogonal DCC formation reactions, for example both boronate and imine formation, 50,56 have been reported.…”

Apical Functionalization of Tribenzotriquinacenes

“…Recently, we implemented hexahydroxy TBTQs as tripodal vertices into dynamic covalent or supramolecular cage compounds. The synthesis of these outer‐rim functionalized building blocks was performed by following conventional synthetic protocols developed by other groups .…”

“…Prominent examples for such scaffolds include calixarenes, cyclotriveratrylenes (CTVs), cyclodextrins, corannulenes, or tribenzotriquinacenes (TBTQs) that feature the orthogonal orientation of three annulated indane wings (Figure ). Since the initial report on the 12d‐methyl derivative of the parent TBTQ in 1984 by Kuck, selective functionalization, especially at the outer rim, has been intensively studied in recent years and suitable derivatives have been implemented in covalent organic cage compounds, supramolecular aggregates, metallosquares, cryptophanes, or fullerene receptors . Less frequently, functionalization at the bridgehead or ortho positions has also been reported, thus showcasing the versatility of TBTQ as a curved aromatic building block.…”