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Clusters on Clusters: closo ‐Dodecaborate as a Ligand for Au 55 Clusters
Author(s) -
Schmid Günter,
Pugin Raphaël,
MeyerZaika Wolfgang,
Simon Ulrich
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199911)1999:11<2051::aid-ejic2051>3.0.co;2-o
Subject(s) - chemistry , cluster (spacecraft) , ionic bonding , aqueous solution , ligand (biochemistry) , derivative (finance) , sodium , ion , inorganic chemistry , crystallography , organic chemistry , financial economics , economics , programming language , biochemistry , receptor , computer science
The exchange of PPh 3 in Au 55 (PPh 3 ) 12 Cl 6 by Na 2 [B 12 H 11 SH] using a phase‐transfer reaction from CH 2 Cl 2 to water needs 6 weeks for reaction, but finally results in the quantitative formation of Au 55 [(B 12 H 11 SH)Na 2 ] 12 Cl 6 ( 2 ). Cluster 2 , which is of considerable stability in aqueous solution, has been characterized by 1 H‐NMR, 11 B‐NMR, and IR spectroscopy as well as by transmission electron microscopy (TEM). The Na + cations can be exchanged by (octyl) 4 N + making the resulting cluster 4 soluble in polar organic solvents. The electrical properties of 2 and 4 are compared with those of Au 55 [Ph 2 PC 6 H 4 SO 3 N(octyl) 4 ] 12 Cl 6 ( 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.