NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
A molecular dynamics study of chloride binding by the cryptand SC24The capture of chloride from water by the tetraprotonated form of the spherical macrotricyclic molecule SC24 was studied using molecular dynamics simulation methods. This model ionophore represents a broad class of molecules which remove ions from water. Two binding sites for the chloride were found, one inside and one outside the ligand. These sites are separated by a potential energy barrier of approximately 20 kcal mol-1. The major contribution to this barrier comes from dehydration of the chloride. The large, unfavorable dehydration effect is compensated for by an increase in electrostatic attraction between the oppositely charged chloride and cryptand, and by energetically favorable rearrangements of water structure. Additional assistance in crossing the barrier and completing the dehydration of the ion is provided by the shift of three positively charged hydrogen atoms of the cryptand towards the chloride. This structural rigidity is partially responsible for its selectivity.
Document ID
20040089073
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Owenson, B.
(NASA Ames Research Center Moffett Field CA United States)
MacElroy, R. D.
Pohorille, A.
Date Acquired
August 21, 2013
Publication Date
January 1, 1988
Publication Information
Publication: Journal of molecular structure
Volume: 179
ISSN: 0022-2860
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NCA2-108
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
NASA Center ARC

Available Downloads

There are no available downloads for this record.
No Preview Available