Deepening Cavitands

Rudkevich, Dmitry M.; Rebek, Julius

doi:10.1002/(sici)1099-0690(199909)1999:9<1991::aid-ejoc1991>3.0.co;2-5

Cited by 200 publications

(140 citation statements)

References 80 publications

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“…(1) (terpyridyl) 2 , wR2 ϭ 0.3714 (for all data). Solvent molecules and alkyl chains were refined isotropically, all other non-hydrogen atoms were refined anisotropically.…”

Section: Capsulementioning

confidence: 99%

A Versatile Six-Component Molecular Capsule Based on Benign Synthons − Selective Confinement of a Heterogeneous Molecular Aggregate

et al. 2001

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Solvent interactions in the formation of novel H‐bonded capsules, comprised of four substituted terpyridines and two C‐methylcalix[4]resorcinarenes (both synthons synthesized using “green” methodology), are shown to determine the size and shape of the guest cavity. Two representative host‐guest complexes showing centred and off‐centred apexes with respect to the calixarenes are described in detail, showing the inclusion of four guest molecules in the solid state.

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“…(1) (terpyridyl) 2 , wR2 ϭ 0.3714 (for all data). Solvent molecules and alkyl chains were refined isotropically, all other non-hydrogen atoms were refined anisotropically.…”

Section: Capsulementioning

confidence: 99%

A Versatile Six-Component Molecular Capsule Based on Benign Synthons − Selective Confinement of a Heterogeneous Molecular Aggregate

et al. 2001

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“…[8,9] These receptors form kinetically very stable complexes with suitable guests, and it has been shown that complex formation is even possible in water. [10] Another receptor in which conformational control is based on intramolecular hydrogen bonds has been introduced by ourselves.…”

Section: Introductionmentioning

confidence: 99%

Fine Tuning of the Cation Affinity of Artificial Receptors Based on Cyclic Peptides by Intramolecular Conformational Control

Kubik¹,

Goddard²

2001

Eur. J. Org. Chem.

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A series of cyclic hexapeptides consisting of alternating 4-substituted 3-aminobenzoic acid units (R = CH 3 , Cl, CH 2 OCH 3 , OCH 3 , COOCH 3 ) and residues of the natural amino acid proline has been prepared and their ion affinities have been investigated. Whereas the unsubstituted parent compound (R = H) is able to bind cations through cation−π interactions with the aromatic subunits, as well as anions through hydrogen bonding with the peptide NH groups, the introduction of substituents at the 4-positions of the aromatic rings results in complete loss of the anion affinity. The cation complex stabilities depend on the substituents and cover a wide range from K a = 140 M −1 for R = CH 3 to K a = 10800 M −1 for R = COOCH 3 (K a = 1260 M −1 for R = H) with n-butyltrime-

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“…[4±7] Supramolecular systems that combine a biomimetic coordination core with a cavity are an attractive topic for the chemist. [8±14] A possible way to construct them is to use readily available building blocks, such as cyclodextrins, [15] cyclotriveratrylenes, [16] resorcinarenes, [17,18] or calixarenes [19±23] We chose to use a calix [6]arene for the following reasons: 1) its size allows the inclusion of organic molecules, 2) it can be easily functionalized, 3) its carbon skeleton is compatible with C 3 symmetry, and finally 4) the macrocycle is highly flexible. This last feature has been analyzed as a handicap for its use as a molecular host.…”

Section: Introductionmentioning

confidence: 99%

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

et al. 2000

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Four novel calix[6]arene-based cuprous complexes are described. They present a biomimetic tris(imidazole) coordination core associated with a hydrophobic cavity that wraps the apical binding site. Each differs from the other by the methyl or ethyl substituents present on the phenoxyl groups (OR1) and on the imidazole arms (NR2) of the calix[6]arene structure. In solution, stable CO complexes were obtained. We have investigated their geometrical and dynamic properties with respect to the steric demand. IR and NMR studies revealed that, in solution, these complexes adopted two distinct conformations. The preferred conformation was dictated only by the size of the OR1 group. When R1 was an ethyl group, the complex preferentially adopted a flattened C3-symmetrical structure. The corresponding helical enantiomers were in conformational equilibrium, which, however, was slow on the 1H NMR time scale at -80 degrees C. When R1 was a methyl group, the low-temperature NMR spectra revealed the partial inclusion of one tBu group. The complex wobbled between three dissymmetric but equivalent conformations. Hence, small differences in the steric demand of the calixarene's skeleton changed the geometry and dynamics of the system. Indeed, this supramolecular control was promoted by the strong conformational coupling between the metal center and the host structure. Interestingly, this was not only the result of a covalent preorganization, but also stemmed from weak interactions within the hydrophobic pocket. The vibrational spectra of the bound CO were revealed to be a sensitive gauge of this supramolecular behavior, similar to copper proteins in which allosteric effects are common.

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Deepening Cavitands

Abstract: The review describes the synthesis of deep open‐ended cavities, based on calixarene and resorcinarene modules, and the host‐guest properties that arise from their unique structures.

Cited by 200 publications

References 80 publications

A Versatile Six-Component Molecular Capsule Based on Benign Synthons − Selective Confinement of a Heterogeneous Molecular Aggregate

A Versatile Six-Component Molecular Capsule Based on Benign Synthons − Selective Confinement of a Heterogeneous Molecular Aggregate

Fine Tuning of the Cation Affinity of Artificial Receptors Based on Cyclic Peptides by Intramolecular Conformational Control

Biomimetic Copper(I)-CO Complexes: A Structural and Dynamic Study of a Calix[6]arene-Based Supramolecular System

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