J. Phys. Chem. B 2009, 113, 33243332
Computer Simulations of Fulleride Anions in Metal-Ammonia Solutions
Christopher A. Howard* and Neal T. Skipper
London Centre for Nanotechnology, surgical incision of Physics and Astronomy, UniVersity College London, Gower Street, London, WC1E 6BT, United Kingdom ReceiVed: September 19, 2008; revise Manuscript ReceiVed: December 12, 2008
Monte Carlo computer poser has been used to study the ener give riseics and local organize of fulleride anions C60n- (n ) 0, 2, 4, 6) in metal-ammonia solutions. We ?nd that the enthalpy of dissolution is markedly favorable only for n ) 2 and 4, which is in line with experimental observations. Analysis of the structure developed around the fulleride anions shows two strong solvation shells of ammonia at distances of around 6.75 and 9.5 Ã
from the fulleride center of mass. This is in excellent agreement with high-resolution neutron diffraction studies of K5C60 in ammonia. The uncharged fullerene (n ) 0) induces no discernible orientational order in the neighboring solving. In contrast to this, there is progressively stronger henry-bonding of the ?rst-shell solvent to the anions (n ) 2, 4, 6), approaching angiotensin converting enzyme hydrogen-bond per molecule for n ) 6.
This maximum of one hydrogen bond per ammonia to the fulleride anion is found to permit intersolvent hydrogen bonding within and across the solvation shells similar to that found in bulk liquid ammonia. Comparison of the cations Li+, Na+, K+, and Ca2+ shows that only the potassium has a tendency to form precede ion-pair complexes with the fulleride anion. This work therefore highlights the mechanisms by which metal-ammonia solutions are able to push aside high concentrations of fullerene salts.
Introduction Since its discovery in 1985, Buckminsterfullerene (C60) and its derivatives shit been the subject of intensive scienti?c and technological activity.2,3 However, our ability to curb fullerenes is limited by the low solubility of these...If you want to get a full essay, order it on our website: Orderessay
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