ISSN:
1434-1948
Keywords:
Gold clusters
;
closo-Dodecaborate
;
Conductivity
;
Charging energy
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The exchange of PPh3 in Au55(PPh3)12Cl6 by Na2[B12H11SH] using a phase-transfer reaction from CH2Cl2 to water needs 6 weeks for reaction, but finally results in the quantitative formation of Au55[(B12H11SH)Na2]12Cl6 (2). Cluster 2, which is of considerable stability in aqueous solution, has been characterized by 1H-NMR, 11B-NMR, and IR spectroscopy as well as by transmission electron microscopy (TEM). The Na+ cations can be exchanged by (octyl)4N+ making the resulting cluster 4 soluble in polar organic solvents. The electrical properties of 2 and 4 are compared with those of Au55[Ph2PC6H4SO3N(octyl)4]12Cl6 (3), the ammonium derivative of the sodium salt. Cluster 3 shows the expected increase of activation energy in the temperature range of 130-250 K owing to the increase of cluster spacing compared with the sodium derivative. However, clusters 2 and 4, show electromigration in the electric field, caused by the huge amount of ionic charges in the ligand shell.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
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