ACCEPTED MANUSCRIPT
4
No signal for polyselenides anions or dibenzylpolyselenides were
1
8b
77
11
detected. Eggert reported the Se NMR shifts for BnSe
x
Bn (x=2-4)
Krief, A., Derock, M.,Tet. Lett, 2002, 43, 3083–3086.
(a) Comasseto, J. V.; Ferreira, J. T. B.; Val Fontanillas, J. A.,
12
and using the specified experimental conditions these higher selenides
were not observed.
J.Organornet. Chem., 1984, 277, 261. (b) Ferreira, J. T. B.;
Comasseto, J. V.; Braga, A. L., Synth.Commun.,1982, 12, 595.
3
. Conclusions.
(
c)Ferraz, H. M. C.; Petragnani, N. Can.J. Chem., 1985, 63, 3216.
13
Martynov, A.V., Monareva, N.S., Larina, L.I., Amosova,
(1). If S.V.,Russian J. Org. Chem., 2013, 49, 943–945.
4
The results shows that the generation of pure NaHSe (3) was very
sensitive to the stoichiometric ratio between Se (2) and NaBH
0
0
14
there is an excess of Se (2), then selenides or diselenides (or a
mixture) were obtained. If NaBH
7) was generated. Either way, the benzyl selenol (6) was always the
Yang, X., Wang, Q. Tao, H. and Xu, H.,J. Chem. Research (S),
4
(1) was in excess, dibenzyl selenide 2002, 160–161.
15
(
de Mello, M.B.M. Clososki, G. C. ,Piovan, L., Oliveira, A.R.M.,
main product when there was a small error in the measurement of J.Organomet. Chem., 2015, 794, 11-16.
1
6
NaBH
equilibrium with NaHSe (3) and is not formed as part of an oxidation
process on extraction. In addition, NaBH (1) is not basic enough to
deprotonate NaHSe (3) but can easily deprotonate benzyl selenol (6),
yielding the corresponding selenolate. For the Na Se (4) alkylation
process, any deviation of the stoichiometry of NaBH (1) used always
4
(1). We also demonstrated that Na
2
Se
2
(4) formation is in
Klayman, D.L. and Griffin, T.S., J. Am. Chem. Soc., 1973, 95,
97-199.
7
1
1
4
McFarlane, W., Wood, R.J., J.C.S. Dalton, 1972, 1397-1402.
18
a) Eggert, H., Nielsen, O., Henriksen, L., J. Am. Chem. Soc.,
986, 108, 8, 1725-1730.; b) Johannsen, I., Eggert, H., J. Am.
Chem. Soc.,1984, 106, 1240-1243.
2
2
1
4
leads to the formation of benzyl selenol (6) in small amounts and
dibenzyl diselenide (8) as the major compound. In a last attempt to
1
9
Bjorgvinsson, M., Schrobilgen, G. J., Inorg. Chem., 1991, 30,
detect a negative selenium ion, (8) was reduced, using the established 2540-2547.
0
20
protocol and one equivalent of Se (2) was added to the resulting
Lyons, L.E., Young, T.L., Aust.J.Chem., 1986, 39, 511-27.
2
1
colorless solution. No signal was observed for the presence of
BnSeSe (13), which after alkylation regenerates the dibenzyl
Cusik, J., Dance, I., Polyhedron, 1991, 10, 2629-2640.
-
22
77
In all Se NMR spectra diphenyl diselenide was used as a
2
-
2-
diselenide (8). It is clear that Se or Se
2
or any other selenium anion
capillary reference.
7
7
1
23
does not give any signal in the Se { H} NMR spectrum although using
an alkylating agent allowed the trapping of several selenium anions in
Reich, H. J., http://www.chem.wisc.edu/areas/reich/handouts/
nmr/se-data.htm, accessed in 10/11/2015.
7
7
solution. Moreover, several insights over the Se NMR chemical shifts
were presented that can help researches in their works in the synthesis
of selenium compounds, been them organic or inorganic ones.
24
Brown, C.A. and Krishnamurthy, S., J. Org. Chem., 1978, 43,
2
731-2732.
25
Selenium species are very sensitive with changes in
electronegativity around the nucleus. Selenium negative species
should have a low frequency while positive species should have a
high frequency shift.
The variations in the Se NMR chemical shift can be attributed
to its medium dependence properties, especially with temperature
changes.
4
. Acknowledgements
We are grateful to the Brazilian funding agencies Fundação Araucária,
CAPES and CNPq for financial support. We are also grateful to the
NMR Center of UFPR for all NMR analyses.
26
77
5
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1