On Jul 21, 2012, at 11:52 AM, Justin Jones wrote: > Unfortunately, their [sic] isn't a "general rule" for good versus bad > nucleophiles.
Actually, there is: The theory of hard and soft acids and bases, developed by Ralph Pearson, generalizes to nucleophiles and electrophiles (Lewis bases and acids, respectively). cf: http://en.wikipedia.org/wiki/HSAB_theory Briefly, "hard" nucleophiles prefer "hard" electrophiles, and interact primarily via electrostatic attraction, and "soft" nucleophiles prefer "soft" electrophiles, and orbital interactions dominate. So Mg++ prefers oxygen to sulphur, and Hg++ prefers sulphur to oxygen. William G. Scott Professor Department of Chemistry and Biochemistry and The Center for the Molecular Biology of RNA 228 Sinsheimer Laboratories University of California at Santa Cruz Santa Cruz, California 95064 USA
