in pentane). Orange solid, yield 8 mg (0.016 mmol, 6%). In the 1H-
NMR, the signals of the isomeric mixture were assigned to (E)-13
and (Z)-13 on the basis of the chemical shifts of the nitrophenyl
protons, which are shifted upfield in (Z)-13 as a result of the
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1
additional shielding provided by the Mes*.34 (E)-13: H-NMR
(CDCl3, 400 MHz): d = 8.22 (m, 2H, Ar), 7.71 (m, 2H, Ar) 7.51 (s,
23 U. H. F. Bunz, Chem. Rev., 2000, 100, 1605.
2H, Mes*), 7.14–7.24 (m, 3H, Ar), 6.90 (m, 2H, Ar), 1.54(s, 18H,
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25 M. M. Haley and R. R. Tykwinsky, Carbon-Rich Compounds, Wiley-
VCH, Weinheim, 2006.
1
tert-Bu), 1.33 ppm (s, 9H, tert-Bu). (Z)-13: H-NMR (CDCl3,
400 MHz): d = 8.02 (m, 2H, Ar), 7.51–7.59 (m, 2H, Ar) 7.51
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(s, 2H, Mes*), 7.35–7.37 (m, 3H, Ar), 7.00 (m, 2H, Ar), 1.54 (s,
1
18H, tert-Bu), 1.34 ppm (s, 9H, tert-Bu). 31P-{ H}-NMR (CDCl3,
162 MHz): 344.4 ppm, 343.8 ppm. ESI MS: m/z [M++Ag] 642.18
(100).
Acknowledgements
This work was supported by the Swedish Research Council, the
Go¨ran Gustafsson Foundation, the Carl Trygger Foundation,
COST action 0802 PhoSciNet, and Uppsala University through
the U3MEC molecular electronics priority initiative. We thank Dr.
Jin-Li Cao and Prof. Jin Qu (Nankai University, China) for the
X-ray structure determination of 3.
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