Encapsulation of N2, O2, Methanol, or Acetonitrile by Decamethylcucurbit[5]uril(NH4+)2 Complexes in the Gas Phase:  Influence of the Guest on “Lid” Tightness

Kellersberger, Katherine A.; Anderson, Joseph D.; Ward, Sarah; Krakowiak, Krzysztof E.; Dearden, David V.

doi:10.1021/ja017031u

Cited by 109 publications

(159 citation statements)

References 12 publications

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“…Cucurbiturils (CBs), [9][10][11] however, are more promising in this regard. These are cyclic structures based on five or more glycouril groups ( Figure 5).…”

Section: Engineering Permanent Microporosity In the Liquid Statementioning

confidence: 99%

“…For example, the cyclic pentamer CB[5] has been found able only to include small species such as H 2 O, N 2 , O 2 , CH 3 OH or CH 3 CN. [10] The notoriously low solubilities of CBs in organic solvents can be increased by adding organic substituents to their peripheries. [9,11] Resulting solutions, even in modestly bulky solvents such as cyclohexane, are therefore potential examples of Type 2 porous liquids.…”

Section: Engineering Permanent Microporosity In the Liquid Statementioning

confidence: 99%

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Porous Liquids

O'Reilly

Giri

James

2007

Chemistry A European J

257

242

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The aim of this article is to put forward the novel concept of porous liquids, or, more precisely, liquids with permanent microporosity. In contrast to the small, transient cavities that exist between the molecules of any liquid (here called "extrinsic" porosity), we suggest that a truly microporous liquid could exist if it had empty pores within the molecules of the liquid ("intrinsic" porosity). By using rigid host molecules with restricted access windows, any unwanted occupation of the pores could be prevented (i.e., the pores could be kept empty and available so that the liquid would be genuinely microporous). The liquid could have permanent, well-defined, empty pores capable of molecular recognition when exposed to other species (e.g., gases etc.). We stress that these phases are not the same as simple solutions of host species, in which any pores would normally be occupied by solvent molecules. In microporous liquids, any solvent molecules, if present, would be deliberately sterically excluded from the host cavities, to leave them readily accessible. Microporous liquids would be of considerable fundamental interest. They could combine properties of microporous solids, such as size- and shape-selective sorption and so forth, with the rapid mass transfer, fluidity and fast kinetics of liquids. Some synthetic approaches to these materials are discussed in this article. Also, whilst the overall concept of microporous liquids is new, literature is described which suggests that some examples have arguably already been reported, even if they have not previously been recognised and characterised in such terms.

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“…Cucurbiturils (CBs), [9][10][11] however, are more promising in this regard. These are cyclic structures based on five or more glycouril groups ( Figure 5).…”

Section: Engineering Permanent Microporosity In the Liquid Statementioning

confidence: 99%

Section: Engineering Permanent Microporosity In the Liquid Statementioning

confidence: 99%

Porous Liquids

O'Reilly

Giri

James

2007

Chemistry A European J

257

242

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“…24 Buschmann et al 25 reported that cucurbituril could complex volatile organic molecules from the gas phase. Dearden et al 26 also found that decamethylCB [5] with 4 NH ＋ formed two tight "lids" on its two carbonyl-fringed portals. However, the small gas molecules such as N 2 , O 2 , CH 3 OH and CH 3 CN still were accommodated by decamethylCB [5]( 4 NH ＋ ) 2 complexes in the gas phase.…”

Section: Discussion Of the Separation Mechanism Of Pspmentioning

confidence: 95%

Studies on Chromatographic Properties of Perhydroxycucurbit[6]uril as a New Type of Gas Chromatographic Column Packing Material

Wang

Xiong-quan

et al. 2008

Chin. J. Chem.

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Perhydroxycucurbit [6]uril {(HO) 12 CB[6]} has been used successfully as a stationary phase for packed column gas chromatography for the first time. Perhydroxycucurbit[6]uril stationary phase (PSP) exhibited wide operational temperature, outstanding thermostability and good selectivities to various organic compounds, such as alkanes, aromatic hydrocarbons, alcohols, esters, ketones, amines, etc. It was also found that some positional isomers, such as disubstituted benzenes could be well separated on this column. PSP has excel1ent separation abilities to some complicate samples, for example, commercial toilet water. Some mechanism of the new packing for GC-separation was preliminarily discussed. It was observed that the partial inclusion complexation of PSP with analytes could improve separation selectivity and column efficiency, instead of complete inclusion. Moreover, PSP exhibited low baseline shift even at dramatically programmed temperature for complicate samples covering a wide boiling point range so as to fast assay.

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“…Os opérculos das cucurbiturilas menores, como a CB [5] e a decametil-CB [5], possuem tamanhos compatíveis com o tamanho dos íons NH 4 + e Cs + para o CB [6] 67 . Estes íons acabam, portanto, preenchendo toda a área dos opérculos, atuando como "tampas da abóbora" 57 , que podem ser removidas em meio básico. Assim sendo, é possível inserir espécies dentro das cavidades e lacrá-las posteriormente.…”

Section: Compostos De Inclusão Com Cucurbitandosunclassified

Cucurbiturilas

Demets¹

2007

Quím. Nova

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Recebido em 7/8/06; aceito em 9/11/06; publicado na web em 17/7/07 CUCURBITURILS. This review article describes the properties and the main applications of the glicol[n]urils. These compounds are cavitands made of n glycolurilic units arranged in circles, giving rise to extremely symmetric toroidal molecules. The cucurbit [n]urils create this way variable-sized hydrophobic cavities and the glycolurilic carbonyles delimit two portals on these cavities, slightly narrower than their internal radii. Their structure, physical and chemical properties favor the formation of inclusion compounds, and turn them into important building blocks for supramolecular chemistry and nanotechnology.Keywords: cucurbiturils; cucurbitands; inclusion compounds. INTRODUÇÃOAs cucurbiturilas foram sintetizadas pela primeira vez por Behrend e colaboradores 1 em 1905, como resultado da condensação da uréia e do glioxal, formando glicolurila e análogos poliméricos na presença de formaldeído. A tecnologia da época não permitiu uma caracterização inequívoca e a estrutura peculiar destes polímeros só foi elucidada pelo grupo de Mock, 80 anos mais tarde 2 . Pela primeira vez demonstrou-se que os cucurbitandos, outra designação desta família de compostos (abreviados também por CB[n]), eram estruturas cíclicas toroidais, compostas por 6 unidades de glicolurila, ligadas por grupos -CH 2 -em suas aminas de simetria D 6H (Figura 1).A nomenclatura oficial deste composto é complexa* e a sua forma de abóbora deu origem a seu nome, de cucurbita em latim (* segundo a IUPAC, o nome da cucurbit[6]urila ou CB[6] seria: dodecaidro-1H, 4H, 14H, 17H-2, 16:3, 15-dimetano-5H, 6H, 7H, 8H, 9H, 10H, 11H, 12H, 13H, 18H, 19H, 20H, 21H, 22H, 23H, 24H, 25H, 26H-2, 3-4a, 5a, 6a, 7a, 8a, 9a, 10a, 11a, 12a, 13a, 15, 16, 17a, 18a, 19a, 20a, 21a, 22a, 23a, 24a, 2 -3 -5a, 26a -tetracosaazabispentaleno[1''',6''':5'',6'',7'']cicloocta[1'', 2'', 3'':3', 4']pentaleno(1',6':5,6,7)cicloocta(1,2,3-gh:1',2',3'-g'h')cicloocta(1, 2, 3-cd:5, 6, 7-c'd')dipentaleno-1, 4, 6, 8, 10, 12, 14, 17, 19, 21, 23, 25-dodecona).Esta estrutura, além de ser simétrica, possui uma cavidade central hidrofóbica relativamente grande, que é capaz de acomodar espécies variadas para a formação de compostos de inclusão, também chamados de caviplexos, como o fazem outras famílias de cavitandos como as ciclodextrinas ou calixarenos. Na cucurbit[6]urila, existem 12 carbonilas orientadas para fora das cavidades, 6 de cada lado, formando assim dois portais para as cavidades, e conferindo à molé-cula um caráter básico de Lewis. Os métodos mais modernos de análise constataram que não eram formados apenas anéis de 6 membros nas sínteses de cucurbiturilas, mas que outros análogos cíclicos com 5 a 11 unidades glicolurílicas também eram formados durante as sínteses. Os recentes avanços em química orgânica sintética permitiram a elaboração de novas rotas, resultando em rendimentos diferenciados na produção destes homólogos. O maior controle sobre a distribuição dos produtos síntese tornou viável a síntese de CB [7] e ...

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Encapsulation of N₂, O₂, Methanol, or Acetonitrile by Decamethylcucurbit[5]uril(NH₄⁺)₂ Complexes in the Gas Phase: Influence of the Guest on “Lid” Tightness

Cited by 109 publications

References 12 publications

Porous Liquids

Porous Liquids

Studies on Chromatographic Properties of Perhydroxycucurbit[6]uril as a New Type of Gas Chromatographic Column Packing Material

Cucurbiturilas

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