Molecular recognition of upper rim functionalized cavitand and its unique dimeric capsule in the solid state

Abstract

Cavitand 1 possesses four 2,2'-bipyridyl pillars on its upper rim that encapsulates small guests, such as nitromethane, acetonitrile, methyl acetate, ethyl acetate, and N-methylacetamide, into a deep cavity to form host-guest complexes in a 1:1 ratio. Nitroethane, N,N-dimethylformamide, and N,N-dimethylacetamide were not bound in this manner. A guest-binding study and molecular mechanics calculations revealed that the four 2,2'-bipyridyl pillars of cavitand 1 created a steric boundary that is responsible for selective guest recognition. In the solid state, cavitand 2 formed a unique chiral capsule 2(2) by π-π stacking interactions between the 2,2'-bipyridyl pillars. A nitromethane molecule was unusually placed deep inside the cavity, as directed by the multiple hydrogen bonding interactions between the nitromethane oxygen atoms, the C-H bonds of the bridge methylenes and the pillar phenyl groups.

Three modes of interactions between anions and phenolic macrocycles: a comparative study

“…Tetraiodoresorcinarene I-RA was prepared by iodination of H-RA with I 2 under basic conditions according to the literature procedure (17% yield). 46 O-RA was synthesized by a bridging procedure with CH 2 BrI. 47 Reference non-macrocyclic I-RM was prepared by iodination of the respective 4,6-di- tert -butylresorcinol with N -iodosuccinimide.…”

Resorcinarene-Based Supramolecular Capsules: Supramolecular Functions and Applications

“…Extension or contraction of the enforced cavity of a cavitand can be used to tune its molecular-recognition properties in terms of selectivity. 31 The coordination geometry of the Cu(I) centers is sensitive to the nature of substituents on the 2,2′-bipyridyl arms. These coordinating 2,2′-bipyridyl arms function as hinges; consequently, the enforced cavity can be expanded or contracted by widening or narrowing the dihedral angle of the 2,2′-bipyridyl arms (Figure 10).…”

Supramolecular Graft Copolymerization of a Polyester by Guest‐Selective Encapsulation of a Self‐Assembled Capsule

“…It was previously shown that the resorcinarene-based coordination capsule 1(BF 4 ) 4 encapsulates hydrogen-bonded pairs of carboxylic acids and av ariety of other molecular guests within its nanosized cavity ( Figure 1a). [16] Thedissymmetric nature of the capsule generates P and M enantiomers, and ad ynamic interconversion of these forms is permitted due to the labile Ag + -N coordination (Figure 1b). [17] The encapsulation of ac hiral biphenyl guest (R)-G1 biases the interconversion, which leads to the M form with an extremely high diastereoselectivity of 98 % de.W eenvisioned that such ad iastereoselective guest encapsulation could be applied in the synthesis of ag raft copolymer.…”