- Cation Complexation by Chemically Modified Calixarenes. 11. Complexation and Extraction of Alkali Cations by Calix[5]- And -[6]arene Ketones. Crystal and Molecular Structures of Calix[5]arene Ketones and Na+ and Rb+ Complexes
-
A series of four calix[5]arenes and three calix[6]arenes (R-calixarene-OCH2COR1) (R = H or But) with alkyl ketone residues (R1 = Me or But) on the lower rim have been synthesized, and their affinity for complexation of alkali cations has been assessed through phase-transfer experiments and stability constant measurements. The conformations of these ketones have been probed by 1H NMR and X-ray diffraction analysis, and by molecular mechanics calculations. Pentamer 3 (R = R1 = But) possesses a symmetrical cone conformation in solution and a very distorted cone conformation in the solid state. Pentamer 5 (R = H, R1 = But) exists in a distorted 1,2-alternate conformation in the solid state, but in solution two slowly interconverting conformations, one a cone and the other presumed to be 1,2-alternate, can be detected. X-ray structure analysis of the sodium and rubidium perchlorate complexes of 3 reveal the cations deeply encapsulated by the ethereal and carbonyl oxygen atoms in distorted cone conformations which can be accurately reproduced by molecular mechanics calculations. The phase-transfer and stability constant data reveal that the extent of complexation depends on calixarene size and the nature of the alkyl residues adjacent to the ketonic carbonyls with tert-butyl much more efficacious than methyl.
- Bell, Steven E.J.,Browne, Julie K.,McKee, Vickie,Anthony McKervey,Malone, John F.,O'Leary, Maeve,Walker, Andrew,Arnaud-Neu, Francoise,Boulangeot, Olivier,Mauprivez, Olivier,Schwing-Weill, Marie-Jose
-
-
Read Online
- Synthesis of new phenylazocalix[5 and 7]arenes
-
Five new phenylazocalix[5 and 7] arenes were synthesized and described. The preparation of these products was based on diazo-coupling reaction.
- Bouoit, Stephanie,Bassus, Jacques,Lamartine, Roger
-
p. 342 - 344
(2007/10/03)
-
- Perforated Monolayers: Design and Synthesis of Porous and Cohesive Monolayers from Mercurated Calixarenes1
-
Mercuration of a series of O-alkylated calixarenes (produced via reaction of tetrahydroxycalixarene, pentahydroxycalixarene hexahydroxycalixarene, and heptahydroxycalixarene with n-bromobutane and with n-bromohexadecane) affords an homologous series of calixarene-based surfactants that form stable monolayers at the air-water interface.Surface pressure-area isotherms, measured for each calixarene, yield limiting areas that are in excellent agreement with values predicted from space-filling models, if it is assumed that the base of each calixarene is parallel and the alkyl chains are perpendicular to the water surface.Introduction of malonic acid to the aqueous subphase results in a substantial increase in the coheresiveness of films derived from calixarene-, calixarene-, and calixarene-based surfactants, as judged by changes in surface viscosity.X-ray photoelectron spectroscopic analysis of a Langmuir-Blodgett film, produced from a malonic acid stabilized calixarene monolayer, shows a carboxylate/mercury ratio of 0.9.This value is in excellent agreement with a model that assumes that all of the bound malonate acts as a bridge between adjacent calixarene subunits in an hexagonally packed array.Water evaporation studies, carried out at the air-water interface, reveal that each of the calixarene-, calixarene-, and calixarene-based monolayers, in the presence and in the absence of malonic acid, maintains a porous structure that offers little resistance to the permeation of water, relative to a densely packed aliphatic monolayer of surfactant.
- Markowitz, Michael A.,Janout, Vaclav,Castner, David G.,Regen, Steven L.
-
p. 8192 - 8200
(2007/10/02)
-
- CALIXARENES. 23. THE COMPLEXATION AND CATALYTIC PROPERTIES OF WATER SOLUBLE CALIXARENES
-
A series of water-soluble calixarenes containing dialkylamino groups and carboxyl groups have been prepared by the p-quinonemethide route of functionalization.The formation of host-guest complexes between these calixarenes and nine aromatic hydrocarbons ranging in size from durene to decacyclene has been investigated, and a correlation between the dimensions of the hydrocarbons and the "lower rim" of the calixarene, containing the array of OH groups, has been made.A study of the effect on the acid-catalyzed hydration of N-benzyl-1,4-dihydronicotinamide by p-(carboxyethyl)calixarenes (n=4,5,6,7,8) has shown that the calixarene is more effective than either its larger or smaller analogs.
- Gutsche, C. David,Alam, Iftikhar
-
p. 4689 - 4694
(2007/10/02)
-
- Molecular Inclusion in Functionalized Macrocycles. Part 5. The Crystal and Molecular Structure of 25,26,27,28,29-Pentahydroxycalixarene-Acetone (1:2) Clathrate
-
A phenol-formaldehyde cyclic pentamer, 25,26,27,28,29-pentahydroxycalixarene (1), has been isolated after dealkylation of a fraction of cyclic products from the base-catalysed reaction of p-(1,1,3,3-tetramethylbutyl)phenol and formaldehyde.This compound, which is the first cyclic product with an odd number of phenolic units isolated in such reactions, is able to form an inclusion complex (1:2) with acetone.The symmetry of the macrocyclic molecule is C8 and the acetone molecules interact with the OH crown and with the cavity with O...O and CH3-phenyl contacts respectively.
- Coruzzi, Marilena,Andreetti, Giovanni Dario,Bocchi, Vittorio,Pochini, Andrea,Ungaro, Rocco
-
p. 1133 - 1138
(2007/10/02)
-
