2-Methylresorcinarene: a very high packing coefficient in a mono-anion based dimeric capsule and the X-ray crystal structure of the tetra-anion

Puttreddy, Rakesh; Beyeh, Ngong Kodiah; Kalenius, Elina; Ras, Robin H. A.

doi:10.1039/c6cc03289c

Cited by 14 publications

(12 citation statements)

References 38 publications

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“…It has been reported that for optimal encapsulation, the ratio of the guest volume to the host cavity volume should fall within the 55% ± 9% range . Although packing coefficients exceeding this target range have been observed in some cases, especially when there are strong interactions and a good geometric match between the host and the guest, as a general rule high encapsulation ratios are correlated with novel host–guest properties. , To the best of our knowledge, the packing coefficient for 3 ⊃TEA + matches the highest value reported to date and could reflect the conformational changes that accompany guest binding (e.g., bending of the triphenyltriazine planes as seen in the solid state structure discussed above). In other words, the high occupancy ratio seen for 3 ⊃TEA + may benefit from a kind of “induced fit” binding phenomenon. , …”

Section: Resultssupporting

confidence: 59%

Controlling the Recognition and Reactivity of Alkyl Ammonium Guests Using an Anion Coordination-Based Tetrahedral Cage

et al. 2018

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Caged structures have found wide application in a variety of areas, including guest encapsulation and catalysis. Although metal-based cages have dominated the field, anion-coordination-based cages are emerging as a new type of supramolecular ensemble with interesting host-guest properties. In the current work, we report a C-symmetric tris-bis(urea) ligand based on the 2,4,6-triphenyl-1,3,5-triazine spacer, which assembles with phosphate anions to form an AL-type (A = anion, L = ligand) tetrahedral cage, 3, with unusually high packing coefficients (up to 99.5% for the best substrate). Cage 3 is able to adjust its size and shape (from 136 to 216 Å) by bending of the triphenyltriazine plane. This allows it to accommodate relatively large guests. In the case of DABCO, inclusion within the cage allows the degree of methylation to be controlled and the monomethylated product to be isolated cleanly under conditions where mixtures of the mono- and dimethylated adduct are obtained in the absence of cage 3.

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Section: Resultssupporting

confidence: 59%

Controlling the Recognition and Reactivity of Alkyl Ammonium Guests Using an Anion Coordination-Based Tetrahedral Cage

et al. 2018

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“…The combined volume of two ID guests (74%) significantly exceeded the value of 55 ± 9% of the host cavity volume (409 Å 3 ), which Rebek showed a while ago afforded optimal guest binding in solution [50,51]. However, a crystalline sponge experiment was performed under highly forcing and non-equilibrium conditions using a large excess of the guest; we [48] and others [52][53][54] have observed packing coefficients for guests inside supramolecular host cavities of >80% when favourable interactions such as π-stacking between multiple guests and favourable interactions between guests and the cage interior surface result in a particularly compact guest array. In dilute solution-the conditions under which guest binding is normally evaluated-we can imagine that for this reason, the second binding constant K 2 would be substantially smaller than the first binding constant K 1 , in which case, the single-guest binding would dominate the solution speciation behaviour [48].…”

Section: Resultsmentioning

confidence: 82%

Catalysis of an Aldol Condensation Using a Coordination Cage

et al. 2020

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The aldol condensation of indane-1,3-dione (ID) to give 'bindone' in water is catalysed by an M 8 L 12 cubic coordination cage (H w ). The absolute rate of reaction is slow under weakly acidic conditions (pH 3-4), but in the absence of a catalyst it is undetectable. In water, the binding constant of ID in the cavity of H w is ca. 2.4 (±1.2) × 10 3 M −1 , giving a ∆G for the binding of −19.3 (±1.2) kJ mol −1 . The crystal structure of the complex revealed the presence of two molecules of the guest ID stacked inside the cavity, giving a packing coefficient of 74% as well as another molecule hydrogen-bonded to the cage's exterior surface. We suggest that the catalysis occurs due to the stabilisation of the enolate anion of ID by the 16+ surface of the cage, which also attracts molecules of neutral ID to the surface because of its hydrophobicity. The cage, therefore, brings together neutral ID and its enolate anion via two different interactions to catalyse the reaction, which-as the control experiments show-occurs at the exterior surface of the cage and not inside the cage cavity.

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“…While hitherto reported resorcinarene‐based inclusion complexes achieve very high packing coefficients of up to 84 % via strong ionic host‐guest interactions, [31] hemicarceplex 1 ⋅ chloroform 2 utilizes the hemicarcerands adaptivity and the guest‘s mobility, matching electrostatics and sterics of host and guest molecules to obtain a packing coefficient of 91 %.…”

Section: Resultsmentioning

confidence: 99%

An Adaptive Resorcinarene Hemicarcerand

Danielsiek

Dyker

2021

Eur J Org Chem

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A new resorcinarene‐based hemicarcerand was developed, exhibiting pronounced flexibility in size and shape to accommodate several guest molecules. With a series of seven hemicarceplexes, investigated via single‐crystal XRD, the cage molecule showed to align its guests to complement their electrostatic potentials and to adjust its dimensions, according to the guest molecule‘s demand. Though forming equimolar inclusion complexes with most guests, crystallization from chloroform, and benzonitrile produced hemicarceplexes with a guest/host ratio of 2 : 1, exhibiting packing coefficients as high as 91 %. In competition experiments, the hemicarcerand clearly favors p‐xylene over m‐xylene: The host shows to crystallize, solely incarcerating p‐xylene from a 1 : 1 mixture of the two xylenes, and also isolates p‐xylene from the mixture via amorphous precipitation.

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2-Methylresorcinarene: a very high packing coefficient in a mono-anion based dimeric capsule and the X-ray crystal structure of the tetra-anion

Cited by 14 publications

References 38 publications

Controlling the Recognition and Reactivity of Alkyl Ammonium Guests Using an Anion Coordination-Based Tetrahedral Cage

Controlling the Recognition and Reactivity of Alkyl Ammonium Guests Using an Anion Coordination-Based Tetrahedral Cage

Catalysis of an Aldol Condensation Using a Coordination Cage

An Adaptive Resorcinarene Hemicarcerand

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