Hemicarcerands with interiors potentially capable of binding large guests

Bussche-Hünnefeld, Christoph von dem; Bühring, Dirk; Knobler, Carolyn B.; Cram, Donald J.

doi:10.1039/c39950001085

Cited by 37 publications

(33 citation statements)

References 10 publications

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“…Moreover, the (de)complexation processes are controlled by a process known as constrictive binding, which is related to the activation barrier required to trap the guest molecule inside the host cavity through a size‐restricting portal . Several hemicarcerands have been synthesized by joining two cavitands with several linkers and a large variety of compounds have been incarcerated inside hemicarcerands cavities ranging from Xe to large molecules such as ferrocene, adamantine, camphor, or C 60 …”

Section: Introductionmentioning

confidence: 99%

Computational NMR Spectra of o‐Benzyne and Stable Guests and Their Hemicarceplexes

Castro

Romero‐Rivera

Osuna

et al. 2020

Chemistry A European J

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The incarceration of o‐benzyne and 27 other guest molecules within hemicarcerand 1, as reported experimentally by Warmuth, and Cram and co‐workers, has been studied by density functional theory (DFT). The 1H NMR chemical shifts, rotational mobility, and conformational preference of the guests within the supramolecular cage were determined, which showed intriguing correlations of the chemical shifts with structural parameters of the host–guest system. Furthermore, based on the computed chemical shifts reassignments of some NMR signals are proposed. This affects, in particular, the putative characterization of the volatile benzyne molecule inside a hemicarcerand, for which our CCSD(T) and KT2 results indicate that the experimentally observed signals are most likely not resulting from an isolated o‐benzyne within the supramolecular host. Instead, it is shown that the guest reacted with an aromatic ring of the host, and this adduct is responsible for the experimentally observed signals.

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Section: Introductionmentioning

confidence: 99%

Computational NMR Spectra of o‐Benzyne and Stable Guests and Their Hemicarceplexes

Castro

Romero‐Rivera

Osuna

et al. 2020

Chemistry A European J

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“…29, 38, 39 Cram's spherands, cavitands, and related derivatives also fall into this category. 40,41 Fully covalent larger organic cages and cage-like systems not derived from the preformed ring systems just mentioned have also been synthesized via conventional direct organic synthesis starting from a range of precursors. 42 -44 However, in part as a consequence of the nonreversibility of the majority of most classical organic reaction types, such cavity-containing products have tended to be obtained in quite low overall yield.…”

Section: Organic Cage Systemsmentioning

confidence: 99%

Bioinspired Self‐Assembly I: Self‐Assembled Structures

Lindoy

Richardson

Clegg

2012

Bioinspiration and Biomimicry in Chemistry

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“…The cavities of resorcarene-based cavitands have been deepened into compounds such as 41a (Chart 22) by Carylation in the C e -position of the aromatic rings, using the Suzuki and Stille reactions [81]. The p-and m-substituents at the upper rims of these cavitands were successfully used for further derivatisation: triethylene glycol footed deep cavitand 41b is functionalised with four m-amidinium groups at the upper rim and effectively binds nucleotides and even dinucleotides in buffered aqueous and methanol solutions [82].…”

Section: Deep Cavitandsmentioning

confidence: 99%

Resorcarenes: Hollow Building Blocks for the Host-Guest Chemistry

Botta

Cassani

D’Acquarica

et al. 2005

COC

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The continuous search for new qualities and the desirability of controlling the size, shape and the chemical features had led to the successful synthesis of various molecular containers and their complexes starting from resorcarene skeleton. The rigidified cavitands have been extended to capture in their round hug bigger and bigger molecules. By covalent synthesis many kinds of new hosts have been built, that maintain guests in their prison for more and more long time. Self assembly, driven by metal-ligand interaction, van der Waals forces, hydrophobicity and, mainly, hydrogen bonds, is at the base of capsules, a novel type of compounds with a peculiar inner phase, stereochemistry and reactivity. The amazing variety of hollow buildings with a resorcarene-based framework and often unique properties is reviewed. OH HO 1168 Current Organic Chemistry, 2005 Botta et al. RESORCARENES AS CONTAINER 2.1 Resorcarenes and Cations or Charged MoleculesAlso resorcarenes form stable complexes with alkali metal cations (Li I , Na I , K I , Rb I , Cs I ) [14]. The interaction of simple resorcarenes with metal cations and ammonium ions has been extensively studied. The conformational change of the host resorcarene, the most favourable binding locations and the relative binding energies have been investigated by ab initio methods [15]. The same group studied the interaction with cations of resorcarene 3a, (Chart 2) in comparison with its permethylated derivative 3b, by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR-MS) and ab initio calculations [16]. The significance of intramolecular hydrogen bonding for the cone conformation and the presence of intramolecular flip-flop hydrogen bonding in 3a were confirmed by calculations and ND 3 -exchange experiments. Regard to the complexation, the following items were established: i) all the above alkali metal cations formed host-guest complexes by docking inside the cavity of the host; ii) the complexation with larger cations, especially Cs + , was favoured; iii) all the cations formed stable dimer resorcarene capsules. Chart 2. Resorcarenes octol (3a) and octamethyl ether (3b).Conversely, Cu II cations were shown to interact with cyano-4a (Chart 3) and amino-resorcarenes 4b, forming in the latter case a complex with octahedrical geometry, as evidenced by the EPR spectrum; accordingly, the computercalculated structure suggested a three-molecular complex between Cu II and two molecules of 4b, in which the ligands use three of their functionalities at the lower rim to fix the ion with a distorted octahedral coordination [17]. Chart 3. Resorcarenes interacting with metal cations.The interaction of resorc[4]arenes octamethyl ethers such as 4c with Fe III in organic media was analysed by 1 H NMR studies, carried out using Ga III instead of Fe III . As a result, resorcarenes bearing carboalkyloxy groups in the side chains were shown to have two active sites of interaction, the first located at the aromatic upper rim and the other in the vicinity ...

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Hemicarcerands with interiors potentially capable of binding large guests

Cited by 37 publications

References 10 publications

Computational NMR Spectra of o‐Benzyne and Stable Guests and Their Hemicarceplexes

Computational NMR Spectra of o‐Benzyne and Stable Guests and Their Hemicarceplexes

Bioinspired Self‐Assembly I: Self‐Assembled Structures

Resorcarenes: Hollow Building Blocks for the Host-Guest Chemistry

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