Table 3. Free Energy for Silyl Shifts from OFF to ON States for Cyclic Compounds (Figure 4).

			S···S distancea
compound	ΔGrxnb	ΔGOFF →ON (ON→OFF)⧧c,d	ON	OFF	TS
4	–1.1	159.0 (160.0)	15.2	15.1	15.3
5	–52.5	-	15.1	15.2	-
6	64.9	-	15.4	15.2	-
7	40.8	-	15.1	15.2	-
8	24.8	132.7 (107.8)	15.2	13.7	14.8
9	–0.4	126.9 (128.4)	14.5	14.3	15.2
10	63.8	-	14.9	14.4	-
11	76.0	-	14.7	14.5	-
12	–6.8	164.4 (171.1)	18.8	19.2	19.4
13	–42.5	-	18.6	18.6	-
14	59.4	-	19.2	19.3	-
15	33.2	158.6 (125.4)	18.3	18.5	19.5
16	11.7	139.7 (128.1)	18.6	17.9	19.0
17	15.7	159.8 (144.2)	17.0	17.8	19.0
18	49.0	-	18.5	18.1	-
19	61.0	-	17.4	17.9	-

^aDistance between thiol end groups [Å].

^bReaction free energy [kJ/mol].

^cFree energy of activation relative to the OFF state (normal print) [kJ/mol].

^dFree energy of activation relative to the ON state (in italics) [kJ/mol].