Isolation of tetraphenylselenurane

Article abstract of DOI:10.1002/hc.20686

Tetraphenylselenurane has been isolated and structurally characterized by a single crystal structure determination. (a = 1752.1(7), b = 99.6(), c = 1074.2(4) pm, β = 98.97(1)°, P2₁/c) It is a yellow crystalline material that explodes on warming

Full text of DOI:10.1002/hc.20686

Heteroatom Chemistry
Volume 22, Number 3/4, 2011
Isolation of Tetraphenylselenurane
Andre´ Marcel Bienfait, Paul Kubella, Birgit Mueller,
and Konrad Seppelt
Institut fu¨ r Chemie, Anorganische und Analytische Chemie, Freie Universita¨t,
Berlin 14195, Germany
Received 15 June 2010; revised 12 August 2010
RESULTS
ABSTRACT: Tetraphenylselenurane has been iso-
lated and structurally characterized by a single crystal
structure determination. (a = 1752.1(7), b = 99.6(),
c = 1074.2(4) pm, ß = 98.97(1)◦, P21/c) It is a yel-
low crystalline material that explodes on warming to
The method chosen for preparing Se(C6H5)4 was
slightly different than described in [5,6]. Rather
than reacting (C6H5)3Se+Br− or (C6H5)2SeO with
C6H5Li, we have used (C6H5)2SeF2 as a starting
material. (C6H5)2SeF2 has been prepared by fluori-
nation of (C6H5)2Se with XeF2 in essentially qualita-
tive yield. According to its spectral data, it is iden-
tical to the material described before, where it has
been prepared by fluorination of (C6H5)2SeCl2 [7]or
(C6H5)2Se [8] with XeF2.
ꢀ
C
room temperature.
2011 Wiley Periodicals, Inc. Het-
eroatom Chem 22:576–578, 2011; View this article online
at wileyonlinelibrary.com. DOI 10.1002/hc.20686
INTRODUCTION
The reaction of (C6H5)2SeF2 with C6H5Li
in (C2H5)2O between −78 and −40◦C afforded
(C6H5)4Se in essentially quantitative yield. The 77Se
NMR resonance at δ = 377.7 pm is very close to
a previous report (373.7 ppm). In the solid state it
is yellow and decomposes violently upon warming
to room temperature. In the crystal, the compound
appears in isolated molecules with little intermolec-
ular interactions. The environment of the selenium
atom is pseudo-trigonal bipyramidal, as expected.
Two longer (214.9(4), 219.9(4) pm) axial Se C bonds
form an almost linear array (179.2(2)◦), and two
shorter equatorial bonds (193.2(4), 194.4(4) pm have
an angle of 105.48(2)◦; see Table 1 and Fig. 1.
The story of phenyl chalcogenurans began with
G. Wittig already in 1952[1], when Te(C6H5)4 was
isolated as a stable compound. Thirty years later
its crystal structure was determined [2]. Akiba
and Seppelt even managed to obtain Te(C6H5)6
and derivatives as compounds stable up to 300◦C
[3]. Hellwinkel showed that tetraphenylselenurane
might be isolated since he managed to obtain the
bis(biphenylene) selenurane [4]. Finally, Furukawa
et al. could show that reactions of triphenylselenu-
ranium bromide or diphenyl selenoxide with phenyl
lithium obviously produced tetraphenylselenurane
in solution at −100◦C. Clear evidences were 77Se, 13C,
and 1H NMR spectra [5]. It was also shown that the
decomposition in THF resulted in diphenylselenium
and diphenyl with an activation energy of 21.3 kcal
mol−1 [6]. The aim of the present study is to com-
pletely establish the identity of Se(C6H5)4.
DISCUSSION
While Se(C6H5)4 has now been isolated, its de-
composition into Se(C6H5)2 and (C6H5)2 [6] ham-
pers further investigations. Attempts to fluorinate it
further by XeF2 with the aim to get (C6H5)4SeF2,
similar to the procedure of cis-C6H5)4TeF2 [3]
or cis−(biphenyl)2SeF2 [9] failed completely. The
compound Se(C6H5)6 is therefore presently out of
reach.
Dedicated to Professor Kin-ya Akiba on the occasion of his 75th
birthday.
Correspondence to: K. Seppelt; e-mail: seppelt@chemie
.fu-berlin.de.
c
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2011 Wiley Periodicals, Inc.
576

Isolation of Tetraphenylselenurane 577
TABLE 1 Bond Lengths (pm) and Angles (◦) in Se(C6H5)4
Instrumentation
NMR spectra were recorded on a JEOL multinuclear
instrument at 400 MHz for 1H. Chemical shifts given
are relative to TMS, CFCl3, and (CH3)2Se. Raman
spectra were recorded on a RFS 100/S Bruker in-
strument with neodym YAG laser excitation.
Se Cax
Se Ceq
Cax Se Cax
Ceq Se Ceq
193.2(4), 194.4(4)
214.9(4), 219.9(4)
179.2(2)
105.5(2)
Crystal Structure Determination
Bruker Smart CCD 1000 TU diffractometer, Mo Kα
radiation, graphite monochromator, scan width of
0.3◦ in ω, a total of 1800 frames with 10 s per
frame. Semiempirical absorption correction (SAD-
ABS), as implemented in the diffractometer soft-
ware, by equalizing symmetry equivalent reflections.
All atoms except hydrogen are refined anisotropi-
cally; hydrogen atoms are refined isotropically. Ex-
perimental details are summarized in Table 2; fur-
ther experimental details can be obtained free of
charge from the Cambridge Crystallographic Data
Centre via www.ccdc.cam.ac.uk/data-request/cif. by
quoting the CCDC number 780535.
(C6 H )2SeF2. 0.42 g (1.8 mmol) diphenylselenium
5
was added dropwise to a solution of (2.0 mmol) XeF2
in CH2Cl2 at −20◦C in an argon atmosphere. During
2 h stirring, the mixture was allowed to 0◦C while
the color changed from orange over brown to deep
purple. After further stirring for 1 h at room temper-
ature, the solvent was removed in vacuum, yielding
a dark purple crystalline solid.
1
19F NMR (CH2Cl2): δ = −67.18 ppm, J19F-77Se
FIGURE 1 Structure of Se(C6H5)4 in the crystal, Ortep rep-
resentation, 50% probability ellipsoids.
= 533.9 Hz; 77Se{ F} NMR (CH2Cl2): 783 ppm;
19
7.47–7.43 (ortho, para) 1H NMR (CH2Cl2): 7.89–7.87
(meta).
TABLE 2 Experimental Details of the Crystal Structure of
The existence of the sulfur analogue S(C6H5)4
as an intermediate has already been raised by
Furukawa et al. [9], but isolation would have to be
done at −100◦C or below. Bis(biphenyl)sulfurane,
however, is stable at room temperature [10].
We have not been able to isolate the perfluori-
nated analogue, Se(C6F5)4, although it should exhibit
greater stability. Main difficulty has been to obtain
(C6H5)2SeF2 in relatively pure form.
Se(C6H5)4
μ
387.36
a (pm)
b (pm)
1752.1(7)
994.6(4)
c (pm)
1074.2(4)
98.97(1)
1848.9
P21/c, monoclinic
Yellow
ß (deg)
V (106 pm3)
Space group
Color
Size (mm)
0.1 × 0.05 × 0.05
T (◦C)
−140
θ
max
(deg)
52.0
Reflections
Measured
Unique
Parameters
R1(Fo > 4σ(Fo)
R1 (all data)
wR2
EXPERIMENTAL
Material
10974
3610
226
0.0464
0.0906
0.1040
0.985
(C6H5)2Se and C6H5−Li solution in (C4H9)2O were
purchased from Aldrich Co. and distilled at 75◦/10−3
mbar. XeF2 was prepared from the elements under
UV irradiation [11].
Goodness of fit
Heteroatom Chemistry DOI 10.1002/hc

578 Bienfait et al.
(C6 H )4Se. 2 mL (3.6 mmol) C6H5Li (1.8 mol/L
REFERENCES
5
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ACKNOWLEDGMENTS
The authors would like to thank the Deutsche
Forschungsgemeinschaft Se 293-36 and GRK 1582/1
and the Fonds der Chemischen Industrie for support
of this work.
Heteroatom Chemistry DOI 10.1002/hc