Bringing a Molecular Plus One: Synergistic Binding Creates Guest-Mediated Three-Component Complexes

Abstract

C Ethyl -2-Methylresorcinarene (A), pyridine (B), and a set of ten carboxylic acids (Cn) associate to form A•B•Cn ternary assemblies with 1:1:1 stoichiometry, representing a useful class of ternary systems where the guest mediates complex formation between the host and a third component. Although individually weak in solution, the combined strength of the multiple non-covalent interactions organizes the complexes even in a highly hydrogen-bond competing methanol solution as explored by both experimental and computational methods. The interactions between A•B and Cn are dependent on the pKa values of carboxylic acids. The weak interactions between A and C further reinforce the interactions between A and B, demonstrating positive cooperativity. Our results reveal that the two-component system such as that formed by A and B can form the basis for the development of specific sensors for the molecular recognition of carboxylic acids. ASSOCIATED CONTENT Supporting InformationThe Supporting Information is available free of charge on the ACS Publications website at DOI: xxxx.Experimental details, copies of the 1 H, 19 F NMR, DOSY and NOESY data, ITC data, and computational data (PDF). X-ray crystallographic data for A•B, A•C6, B•C1, A•B•C1, A•B•C5, A•B•C7, A•B•C9, and A•B•C10 can be obtained free of charge from the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. CCDC 1938866-1938873 (CIF).

Water Soluble Host–Guest Chemistry Involving Aromatic N-Oxides and Sulfonateresorcinarene

“…ITC data for guest 2 could not be fitted to any binding isotherm in water and buffer system without significant errors (Figures S7a and S8a). Notably, pyridine molecules are known to bind and sit in the hydrophobic cavity of the resorcinarene host 1 [16]. However, the mono-N-oxide analog 2 does not show such behavior due to a comparatively weaker binding.…”

Ternary Cocrystals with Large Soft Cavities: A 1,4‐diiodotetrafluorobenzene (DITFB)⋅4‐Biphenylpyridine N‐oxide (BPNO) Host Assembled by Inclusion of Planar Aromatic Guests

“…[1][2][3][4][5][6][7][8] At present, hosts with an intrinsic cavity, capsule or cage-type structure have been constructed based on various noncovalent interactions to recognize or capture guest molecules among various other applications. [9][10][11] Such hosts include metal-organic, covalent-organic, hydrogen-bonded organic, and halogenbonded organic frameworks, as well as porous organic polymers and inclusion crystals. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Among the aforementioned noncovalent interactions, σ-hole and π-hole bonds are excellent supramolecular interactions owing to their high directionality, tunable binding strength, and hydrophobicity.…”

A Concise Synthesis of a Methyl Ester 2-Resorcinarene: A Chair-Conformation Macrocycle

“…On resorcinarenes themselves, reaction at C2 (see Figure 1 for numbering) is selective over C4 and C6 positions, as these are blocked by the lower rim linkages of the resorcinarene On resorcinarenes themselves, reaction at C2 (see Figure 1 for numbering) i over C4 and C6 positions, as these are blocked by the lower rim linkages of the rene ring. The hydrogen bonded network of hydroxyl groups enhances the aci phenol while increasing π-basicity inside the cavity [27]. Attenuation or cleav O−H bonds, exo to the upper rim, by bases results in increased electron dens oxygen, effectively strengthening the hydrogen bonding [26,[28][29][30].…”