. 2016 Oct 7;8(2):1316–1328. doi: 10.1039/c6sc02390h

Table 1. Estimated pK _a values of M-1–M-3 (M = Li, Na, K) measured in C₆D₆ and THF-D₈ .


Base	pK _a (C₆D₆) ^a	pK _a (THF-D₈) ^a
Na-1/(2.2.2-cryptand)	—	29.2
K-1	22.2	24.5
Na-1	22.5	23.6
Li-1	23.0	23.6
K-2/(2.2.2-cryptand)	≈26 (±1) ^b	—
K-2	18.7	22.3
Na-2	≈16.0 ^c	18.8
Li-2	18.0	19.8
K-3/(2.2.2-cryptand)	22.9	—
K-3	<16 ^d	18.0
Na-3	<16 ^d	<16 ^d
Li-3	<16 ^d	≈16.0 ^c

^aThe calculated pK _a values refer to the conjugated acids.

^bThe pK _a value was estimated to be 26 ± 1, as no deprotonation of Ph₃PCH₂PPh₃ [pK _a(DMSO) = 29.9] but 100% deprotonation of 9-Bu^t-fluorene [pK _a(DMSO) = 24.4] was observed.

^cApproximately 10% deprotonation of 9-Ph-fluorene.

^dNo conversion with 9-Ph-fluorene.

Table 1. Estimated pK a values of M-1–M-3 (M = Li, Na, K) measured in C6D6 and THF-D8 .

Table 1. Estimated pK _a values of M-1–M-3 (M = Li, Na, K) measured in C₆D₆ and THF-D₈ .