Kinetic and Thermodynamic Modulation of Dynamic Imine Libraries Driven by the Hexameric Resorcinarene Capsule

Abstract

The composition of dynamic covalent imine libraries (DCL) adapts to the presence of the hexameric resorcinarene capsule. In the presence of the self-assembled capsule, a kinetic and thermodynamic modulation of the imine constituents of the DCLs was observed, which was induced by an unusual predatory action of the capsule on specific imine constituents. More complex 2 × 2 DCLs also adapt to the presence of the hexameric capsule, showing a thermodynamic and kinetic modulation of the constituents induced by the predatory action of the capsule. By cross-referencing experimental data, a good selectivity (up to 66%) for one constituent can be induced in a 2 × 2 DCL.

Supramolecular Catalysis with Self‐Assembled Capsules and Cages: What Happens in Confined Spaces

“…Finally, after 24 h the 69 / 70 ratio reached the value of 15/60 and remained constant (48 h). These results indicated that 69 was the kinetically favoured product, while 70 was the thermodynamic one [47] …”

“…Differently, the formation of the complex 70 @ C R is unfavoured in enthalpic as well as Gibbs free energy terms [47] . QM calculations indicated that the encapsulation of imine 69 inside C R was driven by the formation of a H‐bonding interaction (Figure 6) between the nitrogen atom of 70 and a bridging water molecule.…”

“…Regarding the 70 @ C R complex, because of the steric demand of the trifluoromethyl group, 70 is forced to stay on the axis that joins two vertexes of the capsule (Figures 6), with the ‐CF 3 group pointing inside the cavity of a resorcinarene macrocycle (Figure 6). In this position the imine moiety of 70 is too far from the bridged water molecules of C R and cannot establish any H‐bonding interactions [47] . Thus, at the origin of the DCL modulation of Scheme 21, there is an effective stabilizating effect of the imine 69 inside the confined space by H‐bonding interactions, while the imine 70 that is unable to interact with the capsule, is expelled from the cavity and then accumulates in the bulk medium.…”

“…The stabilization of products inside the confined space of C R , by H‐bonding interactions is at the basis of the kinetic and thermodynamic modulation of dynamic imine library (DCL) in Scheme 21 [47] . The DCL of imine 69 and 70 , obtained by combining p ‐chloroaniline 66 , benzaldehyde 67 , p ‐CF 3 ‐benzaldehyde 68 , adapts its composition in the presence of C R capsule (Scheme 21).…”

Optimized iminium-catalysed 1,4-reductions inside the resorcinarene capsule: achieving >90% ee with proline as catalyst

“…17,18 The eld has been reviewed, [19][20][21][22][23] and novel applications have been found very recently. [24][25][26][27] In 2016, our group reported that iminium-catalysis can be performed inside capsule I (Fig. 1b).…”