%0 Journal Article
%A Iza, Nerea
%A Guerrero-Martínez, Andrés
%A Tardajos, Gloria
%A Ortiz, María José
%A Palao, Eduardo
%A Montoro, Teresa
%A Radulescu, Aurel
%A Dreiss, Cécile A.
%A González-Gaitano, Gustavo
%T Using Inclusion Complexes with Cyclodextrins To Explore the Aggregation Behavior of a Ruthenium Metallosurfactant
%J Langmuir
%V 31
%N 9
%@ 1520-5827
%C Washington, DC
%I ACS Publ.
%M FZJ-2015-02837
%P 2677 - 2688
%D 2015
%X The aggregation behavior of a chiral metallosurfactant, bis(2,2′-bipyridine)(4,4′-ditridecyl-2,2′-bipyridine)ruthenium(II) dichloride (Ru24C13), synthesized as a racemic mixture was characterized by small-angle neutron scattering, light scattering, NMR, and electronic spectroscopies. The analysis of the SANS data indicates that micelles are prolate ellipsoids over the range of concentrations studied, with a relatively low aggregation number, and the micellization takes place gradually with increasing concentration. The presence of cyclodextrins (β-CD and γ-CD) induces the breakup of the micelles and helps to establish that micellization occurs at a very slow exchange rate compared to the NMR time scale. The open structure of this metallosurfactant enables the formation of very stable complexes of 3:1 stoichiometry, in which one CD threads one of the hydrocarbon tails and two CDs the other, in close contact with the polar head. The complex formed with β-CD, more stable than the one formed with the wider γ-CD, is capable of resolving the Δ and Λ enantiomers at high CD/surfactant molar ratios. The chiral recognition is possible due to the very specific interactions taking place when the β-CD covers—via its secondary rim—part of the diimine moiety connected to the hydrophobic tails. A SANS model comprising a binary mixture of hard spheres (complex + micelles) was successfully used to study quantitatively the effect of the CDs on the aggregation of the surfactant.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000350918500009
%R 10.1021/la504929x
%U https://juser.fz-juelich.de/record/189819