TY  - JOUR
AU  - Iza, Nerea
AU  - Guerrero-Martínez, Andrés
AU  - Tardajos, Gloria
AU  - Ortiz, María José
AU  - Palao, Eduardo
AU  - Montoro, Teresa
AU  - Radulescu, Aurel
AU  - Dreiss, Cécile A.
AU  - González-Gaitano, Gustavo
TI  - Using Inclusion Complexes with Cyclodextrins To Explore the Aggregation Behavior of a Ruthenium Metallosurfactant
JO  - Langmuir
VL  - 31
IS  - 9
SN  - 1520-5827
CY  - Washington, DC
PB  - ACS Publ.
M1  - FZJ-2015-02837
SP  - 2677 - 2688
PY  - 2015
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000350918500009
DO  - DOI:10.1021/la504929x
UR  - https://juser.fz-juelich.de/record/189819
ER  -