Stealth Amphiphiles: Self-Assembly of Polyhedral Boron Clusters.
This is the first experimental evidence that both self-assembly and surface activity are common features of all water-soluble boron cluster compounds. The solution behavior of anionic polyhedral boranes (sodium decaborate, sodium dodecaborate, and sodium mercaptododecaborate), carboranes (potassium 1-carba-dodecaborate), and metallacarboranes {sodium [cobalt bis(1,2-dicarbollide)]} was extensively studied, and it is evident that all the anionic boron clusters form multimolecular aggregates in water. However, the mechanism of aggregation is dependent on size and polarity. The series of studied clusters spans from a small hydrophilic decaborate-resembling hydrotrope to a bulky hydrophobic cobalt bis(dicarbollide) behaving like a classical surfactant. Despite their pristine structure resembling Platonic solids, the nature of anionic boron cluster compounds is inherently amphiphilic-they are stealth amphiphiles.
Vladimír
V
Ďorďovič
Zdeněk
Z
Tošner
Mariusz
M
Uchman
Institute of Macromolecular Chemistry, v.v.i., Academy of Sciences of the Czech Republic , Heyrovský Sq. 2, 16206 Prague 6, Czech Republic.
Alexander
A
Zhigunov
Aalto University , Department of Applied Physics Nanotalo, Puumiehenkuja 2, FI-02150 Espoo, Finland.
Mehedi
M
Reza
Aalto University , Department of Applied Physics Nanotalo, Puumiehenkuja 2, FI-02150 Espoo, Finland.
Janne
J
Ruokolainen
Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic , Flemingovo nam. 2, 166 10 Prague 6, Czech Republic.
Goutam
G
Pramanik
Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic , Flemingovo nam. 2, 166 10 Prague 6, Czech Republic.
Petr
P
Cígler
Květa
K
Kalíková
Stranski-Laboratorium für Physikalische Chemie und Theoretische Chemie, Institut für Chemie, Sekr. TC 7, Technische Universität Berlin , Strasse des 17. Juni 124, D-10623 Berlin, Germany.
Michael
M
Gradzielski
Pavel
P
Matějíček