TABLE 4.

Activation energies ΔE (in kcal/mol) for purines in aqueous mixtures in acetonitrile and in n-butanol

	dA				dG
	Acetonitrile		n-butanol		Acetonitrile		n-butanol
	8%	15%	8%	15%	8%	15%	8%	15%
“Carry its own water”	3.4 (−1.6)*	3.2 (−1.8)	2.0 (−3.0)	1.9 (−3.1)	2.9 (−2.1)	1.9 (−3.1)	2.5 (−2.5)	1.4 (−3.6)
“Injected water”	-†	-	1.5	2.1	-	-	2.1	2.5
“Premixed”	2.5	2.5	-	-	-	-	-	-

^*In parentheses are the TΔS values (in kcal/mol) calculated from Eq. 5 (see text).

^†Dash indicates that the changes in the fluorescence intensity were too small to allow the construction of a meaningful Arrhenius plot, from which ΔE would be calculated.