85483-96-1Relevant articles and documents
Folding of a donor-containing ionene by intercalation with an acceptor
De, Swati,Ramakrishnan
supporting information; experimental part, p. 149 - 156 (2011/10/08)
Cationic ionenes that bear electron-rich 1,5-dialkoxynaphthalene (DAN) units within the alkylene segment were allowed to interact with different types of electron-deficient, acceptor-containing molecules in an effort to realize intercalation-induced folding of the ionenes; the collapse of the chains was expected to occur in such a way that the donor and acceptor units become arranged in an alternating fashion. Several acceptor-bearing molecules were prepared by the derivatization of pyromellitic dianhydride and naphthalene tetracarboxylic dianhydride with two different oligoethylene glycol monomethyl ether monoamines. This yielded acceptor molecules with different water solubility and allowed the examination of solvophobic effects in the folding process. UV/Vis spectroscopic studies were carried out by using a 1:1 mixture of the DAN-ionenes and different acceptor molecules in water/DMSO solvent mixtures. The intensity of the charge-transfer (CT) band was seen to increase with the water content in the solvent mixture, thereby suggesting that the intercalation is indeed aided by solvophobic effects. The naphthalene diimide (NDI) bearing acceptor molecules consistently formed significantly stronger CT complexes when compared to the pyromellitic diimide (PDI) bearing acceptor molecules, which is a reflection of the stronger π-stacking tendency of the former. AFM studies of drop-cast films of different ionene-acceptor combinations revealed that compact folded structures are formed most effectively under conditions in which the strongest CT complex is formed. Know when to fold 'em: When coerced to collapse in a polar solvent in the presence of an electron-deficient amphiphilic folding agent, suitably modified ionenes with a symmetrically positioned electron-rich 1,5-dialkoxylnaphthalene (DAN) unit appear to form an accordion-type folded structure wherein the units are arranged in an alternating fashion (see picture). D=Donor; A=Acceptor. Copyright
Synthesis of new enantiopure proton-ionizable crown ethers containing a dialkylhydrogenphosphate moiety
Kovacs, Ilona,Huszthy, Peter,Bertha, Ferenc,Sziebert, Denes
, p. 2538 - 2547 (2007/10/03)
Seven new enantiopure proton-ionizable crown ethers containing a dialkylhydrogenphosphate moiety were prepared starting from optically active dialkyl-substituted oligoethylene glycols and phosphorus oxychloride followed by mild hydrolysis of the resulting macrocyclic chlorophosphates. Pentaethylene glycols having primary hydroxyl groups gave good yields of 17-crown-6 type ethers. Pentaethylene glycols with secondary hydroxyl groups rendered about the same amount of 17-crown-6 ethers and open chain dihydrogenphosphates in low yields. Tetraethylene glycols are reluctant to undergo macrocyclization with phosphorus oxychloride, especially the ones which contain secondary hydroxyl groups.
Preparation of optically active azophenolic crown ethers containing 1-phenylethane-1,2-diol and 2,4-dimethyl-3-oxapentane-1,5-diol as a chiral subunit: Temperature-dependent enantiomer selectivity in the complexation with chiral amines
Ogasahara, Kazuko,Hirose, Keiji,Tobe, Yoshito,Naemura, Koichiro
, p. 3227 - 3236 (2007/10/03)
With (2S,4S)-2,4-dimethyl-3-oxapentane-1,5-diol and (S)- or (R)-1-phenylethane-1,2-diol as chiral subunits, optically active azophenolic crown ethers (S,S,S,S)-1, (R,S,S,R)-2, (S,S,S,S)-3 and (R,S,S,R)-4 possessing two phenyl and two methyl substituents together with the p-(2,4-dinitrophenylazo)phenol moiety have been prepared in enantiomerically pure forms. Temperature-dependent enantiomer selectivity in the complexation of these crown ethers with chiral amines has been studied by the UV-visible spectroscopic method in chloroform and from the observed association constants, thermodynamic parameters for the complexation have been calculated.
