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. Author manuscript; available in PMC: 2014 Nov 25.
Published in final edited form as: Organometallics. 2013 Jul 2;32(22):10.1021/om400582k. doi: 10.1021/om400582k

Table 1.

Titration Experiments with 1 and Various Lewis Bases. 11B-NMR Data.a

Lewis base boronate complex (ppm) (2)
graphic file with name nihms502339u1.jpg 		borenium ion (ppm) (3)
graphic file with name nihms502339u2.jpg 		boronium ion (ppm) (4)
graphic file with name nihms502339u3.jpg
Et3N (a) 84.8 (85.1)b
DABCO (b) 56.9
pyridine (c) 5.2
2,4-lutidine (d) 39.4 9.7
2,6-lutidine (e) 84.4
DMAP (f) (66.5)b (3)b
proton sponge (g)c (16.2)b
HMPA (h) 64.9 17.8
Ph3P=O (i) 67.4 17.3
n-Bu3P=O (j) 65.1 14.5
Ph3P=S (k) 80.4
(Me2N)3P=S (l) 80.9 46.9
pyridine-N-oxide (m) 64.2 14.4
DMSO (n) 66.1 15
n-Bu3P (o) 33.1 −5.4
benzophenone (p) 35.6d
a

11B NMR spectra were recorded at 128 MHz (CH2Cl2) with proton decoupling. Chemical shifts are reported in ppm from BF3•OEt2 (0.0 ppm) as the external standard.

b

Data in parentheses are from ref. 13.

c

1,8-bis(dimethylamino)naphthalene.

d

2.0 equiv of Lewis base.