Synthetic receptors

Hartley, James H.; James, Tony D.; Ward, Christopher J.

doi:10.1039/a909641h

Cited by 263 publications

(144 citation statements)

References 239 publications

(282 reference statements)

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“…The solvent was evaporated in vacuo and the residue was purified by gradient column chromatography (ethyl acetate/ethanol/water, 100:2:1 to 50: 15:8) to give 7 as a white powder in 90 % yield. 1 , 1 H), 4.92±4.85 (m, 6 H), 4.18±3.35 (m, 38 H UV/Vis spectroscopy: UV/Vis spectra were recorded on a Hewlett Packard HP 8452 UV/Vis spectrophotometer. Irradiation experiments were performed in situ by irradiation of the samples in a 1-cm quartz cuvette in the UV/Vis setup by using a 200-W mercury lamp with a 313-nm band-pass or a 460-nm high-pass filter.…”

Section: Discussionmentioning

confidence: 99%

“…This is especially true for the field of synthetic receptor molecules. [1] External control over the selectivity of receptors gives access to tunable host molecules and ideally enables the release and/or uptake of guest molecules to be induced at will. Clear examples can be found among reported work on switchable cation receptors, which has led to tunable receptor molecules that enable the controlled release and transport of cations.…”

Section: Introductionmentioning

confidence: 99%

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Photocontrolled Release and Uptake of a Porphyrin Guest by Dithienylethene‐Tethered β‐Cyclodextrin Host Dimers

Mulder

Juković

Leeuwen

et al. 2004

Chemistry A European J

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Two photoswitchable dithienylethene‐tethered β‐cyclodextrin dimers were synthesized to function as host molecules with an externally controllable binding affinity. The cyclodextrin cavities of these dimers are linked through their secondary sides by a photochromic dithienylethene unit that is connected to the secondary rim either directly (4) or through propyl spacers (9). Irradiation with light switches these dimers between a relatively flexible (open) and a rigid (closed) form. The binding properties of the dimers depend on the configuration of the dithienylethene spacer, as is shown by microcalorimetry performed with tetrakis‐sulfonatophenyl porphyrin (TSPP) as a guest molecule. The differences in binding properties are most pronounced for the more rigid dimer 4, which binds TSPP 35 times more strongly in the open form (4 a) than in the closed form (4 b). The values found for the enthalpy of binding (ΔH°) indicate that this difference in binding is due to the loss of cooperativity between the two β‐cyclodextrin cavities in the closed form. Molecular modeling shows that 4 b is not able to bind TSPP effectively in both cyclodextrin cavities. The open and closed forms of the more flexible dimer 9 show no substantial difference in their binding of TSPP. Thermodynamic values indicative of strong binding of TSPP by two β‐cyclodextrin cavities were measured for both forms of the dimer, and molecular modeling confirms that both are flexible enough to tightly bind TSPP. The binding differences between the forms of dimer 4 allow the photocontrolled release and uptake of TSPP, which renders control of the ratio of complexed to free TSPP in solution possible.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Photocontrolled Release and Uptake of a Porphyrin Guest by Dithienylethene‐Tethered β‐Cyclodextrin Host Dimers

Mulder

Juković

Leeuwen

et al. 2004

Chemistry A European J

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“…This is demonstrated by a great number of calixarenes providing functional side arms for supramolecular interaction or the attachement of a sensing unit [4]. While the function of a side arm, being designed for the specific interaction with a guest molecule or mutually between the calixarene molecules, very often make use of hydrogen bonding [5], the π···π-stacking mode of interaction is far less considered [6,7]. In particular the pyrene moiety, which is generally known to be inclined to stacking formation [8], is given reference only in a [9,10,11].…”

Section: Introductionmentioning

confidence: 99%

Crystal structures of a calix[4]arene controlled by two affixed pyrene units

Gruber

Seichter

Weber

2008

Supramolecular Chemistry

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“…A complexação molecular se dá pelo contato entre as superfícies moleculares, por isso os receptores moleculares apresentam superfícies côn-cavas ou cavidades (HARTLEY et al 2000), para interagir com os grupos das moléculas hóspede. O processo de complexação é favorecido por entalpia (formação de interações que diminuem a energia) e desfavorecido por entropia (formação de uma espé-cie molecular a partir de duas e perda de modos de liberdade após a complexação).…”

Section: Figura 3 -Nanotubos Multicamada Purificadosunclassified

Complexação Molecular Por Receptores Sintéticos

Lazzarotto¹

2011

Publ.Exatas

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RESUMOA complexação molecular por receptores sintéticos, tais como ciclodextrinas, calixarenos e éteres de coroa, foi revisada com foco na inclusão de íons orgânicos e metálicos.Palavras-chave: Química supramolecular. Calixarenos. Complexação. ABSTRACTMolecular complexation by synthetic receptors like cyclodextrines, calixarenes and crown ethers has been revised with a special focus in the inclusion of organic and metal ions.Keywords: Supramolecular chemistry. Calixarenes. Complexation. IntroduçãoExiste hoje à disposição uma grande quantidade de informação a respeito de estruturas de molécu-las orgânicas e inorgânicas, e diversas metodologias sintéticas têm sido desenvolvidas para a obtenção de novas moléculas orgânicas e inorgânicas, a partir da construção de ligações covalentes. Na formação destas ligações estão envolvidas energias entre 200 a 800 kJ.mol -1 , porém metodologias para a formação de ligações não-covalentes são pouco conhecidas e pouco exploradas na síntese de agregados moleculares e apenas recentemente têm sido exploradas para a obtenção de estruturas organizadas.Estas energias são da ordem de 12-20 kJ.mol -1 para as ligações de hidrogênio e da ordem de 5 kJ.mol -1 para interações dipolares (STEED; ATWOOD, 2000). A dificuldade para a síntese de complexos supramoleculares é consequência das baixas energias envolvidas, da ordem de grandeza similar às energias de movimentos translacionais e de rotação das ligações. Assim, mudanças conformacionais podem levar à perda das interações entre as espécies químicas. Um exemplo está abaixo, em que o número de conformações do receptor acíclico, originárias da rotação em torno das ligações C-C, é bem maior do que o número de conformações para o receptor cíclico (HANCOCK, 1992). No complexo formado, o número de conformações possíveis é reduzido; logo existe uma perda maior na entropia para o receptor acíclico (valor de DS negativo) em comparação com o receptor cíclico. Este ganho de energia pelo efeito entrópico na complexação torna o complexo molecular com o receptor acíclico menos estável. Este efeito é conhecido como efeito macrociclo.

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Synthetic receptors

Cited by 263 publications

References 239 publications

Photocontrolled Release and Uptake of a Porphyrin Guest by Dithienylethene‐Tethered β‐Cyclodextrin Host Dimers

Photocontrolled Release and Uptake of a Porphyrin Guest by Dithienylethene‐Tethered β‐Cyclodextrin Host Dimers

Crystal structures of a calix[4]arene controlled by two affixed pyrene units

Complexação Molecular Por Receptores Sintéticos

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