Lyotropic behaviour of diruthenium (II,III) alkoxybenzoates in dodecane.

M. RUSJAN; B. DONNIO; B. HEINRICH; F. D. CUKIERNIK; D. GUILLON

LANGMUIR

American Chemical Society

Año: 2002 vol. 26 p. 10116 - 10121

0743-7463

   The lyotropic behavior of three mixed valence diruthenium(II,III) alkoxybenzoates in dodecane mixtureshas been analyzed. The studied compounds, namely, Ru2(3,4,5-B3OC14)4Cl [1] (3,4,5-B3OC14 ) 3,4,5-tri(n-tetradecyloxy)benzoate), Ru2(3,4-B2OC14)4Cl [2] (3,4-B2OC14 ) 3,4-di(n-tetradecyloxy)benzoate),and Ru2(3,5-B2OC14)4Cl [3] (3,5-B2OC14 ) 3,5-di(n-tetradecyloxy)benzoate), were investigated at threedifferent temperatures (40, 70, and 100 °C) for variable solvent concentrations (between 0 and 70 wt %).Mixing the complexes with up to 40-60 wt % of dodecane did not alter the nature of the low-temperaturemesophase exhibited by the pure compound still showing a columnar hexagonal phase. However, it resultedin a substantial decrease of the viscosity for all of them and a depression of the melting point for [2]. Forsolvent concentrations greater than 40-60 wt % and high temperatures, the mixtures exhibited also anematic columnar mesophase prior to the transition to the isotropic solution. At a structural level, theincorporation of solvent resulted in the swelling of the columns, leading to an increase of the intercolumnardistance up to a point where the columns lost their hexagonal order to give the columnar nematic phase.At higher concentrations of solvent, the mesophase dissolved into the solvent.