Facile and reproducible syntheses of bis(dialkylselenophosphenyl)-selenides and -diselenides: X-ray structures of (iPr2PSe) 2Se, (iPr2PSe)2Se2 and (Ph2PSe)2

Article abstract of DOI:10.1039/b603197h

Facile and reproducible methods for the syntheses of bis(di-iso- propylselenophosphinyl)selenide (ⁱPr₂PSe)₂Se (1), bis(di-iso-propylselenophosphinyl)diselenide (ⁱPr ₂PSe)₂Se₂ (2)

Full text of DOI:10.1039/b603197h

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Facile and reproducible syntheses of bis(dialkylselenophosphenyl)-
selenides and -diselenides: X-ray structures of ( Pr PSe) Se,
i
2
2
i
(
Pr PSe) Se and (Ph PSe) Se
2 2 2 2 2
Chinh Q. Nguyen, Adekunle Adeogun, Mohammad Afzaal, Mohammad A. Malik and Paul O’Brien*
Received (in Cambridge, UK) 3rd March 2006, Accepted 31st March 2006
First published as an Advance Article on the web 21st April 2006
DOI: 10.1039/b603197h
Facile and reproducible methods for the syntheses of
The compounds are stable under air and moisture for several
i
bis(di-iso-propylselenophosphinyl)selenide ( Pr
2
PSe)
bis(di-iso-propylselenophosphinyl)diselenide ( Pr PSe)
and bis(di-phenylselenophosphinyl)selenide (Ph PSe) Se (3) is
2
Se (1),
months.
i
Se (2)
2
toluene
R2PClzHSiCl3zNEt3 DCCA R2PSiCl3z½HNEt ꢀCl (1)
2
2
3
6h,rt
2
2
reported.
toluene
2
R2PSiCl3z3Se DCCA (R PSe) SezSi2Cl6
(2)
(3)
2
2
20h,reflux
The most common method reported for the preparation of
selenophosphates or selenophosphinates involves the reaction of
toluene
Na
x
E
y
2 2
(E = S, Se, Te) with PhPCl or Ph PCl. The preparation
2R2PSiCl3z4Se DCCA (R PSe) Se2zSi2Cl6
2 2
20h,reflux
of Na E is carried out by the reaction of sodium metal with grey
x y
1–6
selenium in a liquid ammonia solution at 278 uC. Woollins et al.
reported that such reactions give a mixture of products along with
7
unreacted sodium. It was also reported that the results of the
The structure of 1 (Fig. 1) shows that each phosphorus is
bonded with two selenium atoms and the two carbon atoms of the
isopropyl group. One of the selenium atoms (Se(1)) is shared by
both phosphorus atoms. The geometry around P(1) is a distorted
tetrahedron (Se(2)–P(1)–Se(1), 106.25(6)u) whereas the Se(3)–P(2)–
Se(1), 118.05(6)u angle around P(2) shows it to be close to trigonal
planar. The angle P(1)–Se(1)–P(2) 107.50(6)u makes Se(1) distorted
tetrahedral. The difference between the single bonds and double
bonds of selenium and phosphorus is clearly shown by the bond
x y 2
reaction between Na E and Ph PCl are not reproducible and can
be improved, but only slightly, by using a mixture of THF–
ethanol; the ethanol destroys any residual sodium. Using these
7
methods, authors have synthesised [Na (Se PPh ) ?THF?5H O].
2
2
2 2
2
8
Davies
K(Se PPh
Ph PK or Ph
then reacted with InCl
et
al.
(THF)
PLi with selenium. The potassium complex was
to give the indium complex;
prepared
[Li(Se
2
PPh
2
)?THF?TMEDA],
8
2
[
2
2
)
2
2
]
and [In(SePPh
2 3
) ] by the reaction of
2
2
3
˚ ˚
lengths of Se(1)–P(1), 2.274(2) A; Se(1)–P(2), 2.297(1) A which are
8
9
[
In(Se PPh ) ]. Du Mont et al. have inserted Se into a P–P bond
2 2 3
˚
˚
longer than those of Se(2)–P(1), 2.109(1) A; Se(3)–P(2), 2.10(2) A
as expected.
to give selenophosphinates whereas Horn and Lindner prepared
the intermediate R PSi(Me) , by lithiation of diphenylphosphine
2
3
chloride and subsequent reaction with trimethylsilylchloride at
12
Benkeser reported that the combination of
10,11
278 uC.
trichlorosilane with triethylamine will produce trichlorosilyl anion
which can act as a substituent to facilitate the forming of C–Si
1
3
bonds. This reaction was extended by du Mont et al. to make
Ge–Si and P–Si bonds.
There are no reports of a reproducible synthetic method for the
presented selenophosphates or selenophosphinates, or their X-ray
structures. Herein, we report facile and reproducible methods for
i
i
the syntheses of ( Pr PSe) Se (1), ( Pr PSe) Se (2) and (Ph PSe) Se
2
2
2
2
2
2
2
(3) and their X-ray structures.
Compounds 1–3 were prepared by the insertion of Se in to the
i
P–Si bond of the intermediate R PSiCl , (where R = Pr, Ph). The
2 3
reactions are shown in eqn (1)–eqn (3).{ All three compounds are
soluble in common non-polar organic solvents and were crystal-
lized from toluene solution to give transparent yellow cubic
crystals for 1 and transparent orange rods for 2 and 3.
Fig. 1 Thermal ellipsoid plot (50% probability) of the structure of 1.
˚
Selected bond distances (A) and angles (u): Se(1)–P(1), 2.274(2); Se(1)–P(2),
2
.297(1); Se(2)–P(1), 2.109(1); Se(3)–P(2), 2.10(2); P(1)–C(1), 1.832(5);
The School of Chemistry and the School of Materials, The University of
Manchester, Oxford Road, Manchester, UK M13 9PL.
E-mail: paul.obrien@manchester.ac.uk
P(1)–C(4), 1.845(5); P(2)–C(10), 1.837(5); P(2)–C(7), 1.840(5); P(1)–Se(1)–
P(2), 107.50(6); Se(2)–P(1)–Se(1), 106.25(6); Se(3)–P(2)–Se(1), 118.05(6).
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Chem. Commun., 2006, 2179–2181 | 2179

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The structure of compound 3 is similar to the structure of 1 with
the isopropyl groups on phosphorus replaced by phenyl groups.
The bond distances between phosphorus and selenium are also
similar to those observed in 1 and 2 but the geometry around
phosphorus becomes highly distorted tetrahedral due to the steric
hindrance of phenyl groups. The structure of 3 is shown in Fig. 3.
Preliminary results of the reactions of these ligands with
different metals show interesting reactions depending on the metal
e.g. breaking the bond between one phosphorus with the central Se
2 2
to give the chelating (R PSe ) in case of its reaction with
molybdenum and forming a bridge through selenium atoms in
its reaction with copper. The full investigation of these reactions
with a series of metals is under way and is reported in the
14
accompanying communication.
The authors thank RCUK and the EPSRC for funding a Basic
technology project. CQN would like to acknowledge the
Government of Vietnam for funding.
Fig. 2 Thermal ellipsoid plot (50% probability) of the structure of 2.
˚
Selected bond distances (A) and angles (u): P(1)–Se(2), 2.116(1); P(1)–Se(1),
2
.243(1); Se(1)–Se(1A), 2.384(1); C(1)–P(1), 1.837(3); C(4)–P(1), 1.828(3);
C(2)–C(1)–P(1), 111.0(2); C(3)–C(1)–P(1), 114.6(2); C(4)–P(1)–Se(2),
14.79(1); C(1)–P(1)–Se(2), 112.90(1); C(4)–P(1)–Se(1), 111.52(1); C(1)–
P(1)–Se(1), 109.72(1); Se(2)–P(1)–Se(1), 100.91(3); P(1)–Se(1)–Se(1A),
07.65(3). Symmetry transformation used to generate equivalent atoms:
Notes and references
1
{ All the reactions were performed under a nitrogen atmosphere by using
standard Schlenk techniques. All chemicals were bought from Aldrich
Chemical Company Limited and used as received. Solvents were distilled
prior to use. NMR spectra were obtained with chloroform-D6 solution
using a Bruker AC300 FTNMR instrument. Elemental analysis was
performed by the University of Manchester micro-analytical laboratory.
Single crystal X-ray crystallography measurements were made using
graphite monochromated Mo Ka radiation on a Bruker APEX
diffractometer. The structures were solved by direct methods and refined
1
A 1 2 x, y, 2z + K.
The structure of 2 is similar to the structure of 1 with the only
difference being an additional selenium between the two
phosphorus atoms. The compound has crystallographically a
two-fold axis. The selenium from P(1) forms a bond with the
selenium from P(2) so that a bridge of two seleniums is formed
between two phosphorus atoms. The structure is shown in Fig. 2.
2 15
by full-matrix least-squares on F . All calculations were carried out using
1
6
the SHELXTL package. All non-hydrogen atoms were refined with
anisotropic atomic displacement parameters. Hydrogen atoms were placed
in calculated positions, assigned isotropic atoms. CCDC numbers 282911
(1), 291034 (2), 291035 (3). For crystallographic data in CIF or other
electronic format see DOI: 10.1039/b603197h
i
(
Pr PSe)
2
2
Se (1). NEt
3
(30 mmol) was added to a stirring solution of
(30 mmol) in cold toluene (60 mL). The
i
Pr PCl (30 mmol) and HSiCl
2
3
solution was allowed to warm up to room temperature and was further
stirred for 6 h, leading to the formation of a white cloudy precipitate. The
precipitate was filtered off and the resulting colourless solution was refluxed
with grey Se powder (45 mmol) for a further 20 h until all the Se dissolved
to form a clear yellow solution. The solvent was removed under vacuum
and the yellow powder product was washed with cold hexane. The product
was then re-crystallized in toluene to obtain clear yellow crystals of 1 (2.90 g,
yield 41.43%). Elemental analysis calcd (%) for C12
28 2 3
H P Se : C 30.59,
1
H 5.99, P 13.15; found (%): C 31.10, H 6.09, P 13.02; H NMR d =
i
.91 ppm (dq, 4H, CH, Pr, J = 7.2 Hz, J = 12.8 Hz), 1.33 ppm (ddd, 24H,
2
CH
i
, Pr, J =6.9 Hz, J = 20.9 Hz, J = 24.3 Hz).
3
i
(
2 2 2
Pr PSe) Se (2). Using a similar process as for 1 but with 60 mmol grey
Se powder. After reflux for 20 h, all Se dissolved to form a clear dark
orange solution. The solvent was removed under vacuum and the orange
powder product was washed with cold hexane. The product was re-
crystallized in toluene to obtain orange crystals of 2 (3.55 g, yield 43.03%).
28 2 4
Elemental analysis calcd (%) for C12H P Se : C 26.20, H 5.13, P 11.26;
1
found (%): C 26.29, H 5.17, P11.31; H NMR d = 2.62 ppm (ddd, 4H, Pr,
i
i
J = 6.6 Hz, J = 13.4 Hz, J = 26.9 Hz), 1.27 ppm (ddd, 24H, Pr, J = 6.8 Hz,
J = 12.2 Hz, J = 21.8 Hz).
(
Ph
yellow crystals of 3 were obtained (3.92 g, yield 43%). Elemental analysis
calcd (%) for C24 Se : C 47.47, H 3.32, P 10.20; found (%): C 50.51,
2 2 2
PSe) Se (3). Using a similar process as for 1 but using (Ph) PCl,
Fig. 3 Thermal ellipsoid plot (50% probability) of the structure of 3.
˚
H P
20 2
3
1
Selected bond distances (A) and angles (u): Se(1)–P(1), 2.106(2); Se(2)–P(1),
H 3.76, P10.59; H NMR d = 7.87 ppm (ddd, 8H, o-Ph, J = 7.6 Hz, J =
16.1 Hz, J = 22.9 Hz), 7.48 ppm (dd, 8H, m-Ph, J = 6.1 Hz, J = 30.2 Hz),
2.263(2); Se(2)–P(2), 2.293(2); Se(3)–P(2), 2.105(2); P(1)–C(7), 1.802(8);
7
.37 ppm (dd, 4H, p-Ph, J = 3.5 Hz, J = 7.7 Hz).
¯
Crystal data for 1: C12 Se , M = 471.16, triclinic, space group P1,
P(1)–C(1), 1.806(8); P(2)–C(19), 1.821(8); P(2)–C(13), 1.825(8); P(1)–Se(2)–
P(2), 109.01(8); C(7)–P(1)–C(1), 105.4(4); C(7)–P(1)–Se(1), 113.6(3); C(1)–
P(1)–Se(1), 117.1(3); C(7)–P(1)–Se(2), 110.1(3); C(1)–P(1)–Se(2), 108.2(3);
Se(1)–P(1)–Se(2), 102.28(9); C(19)–P(2)–C(13), 106.9(3); C(19)–P(2)–Se(3),
H P
28 2
3
r
˚
˚
˚
a = 7.324(3) A, b = 10.189(5) A, c = 12.669(6) A, a = 101.544(8), b =
3
23
˚
5.067(9), c = 101.157(8), V = 900.7(7) A , Z = 2, rcalculated = 1.737 g cm ,
21
9
m = 6.285 mm , T = 100(2) K. Crystal size 0.35 6 0.25 6 0.10 mm, l =
115.2(3); C(13)–P(2)–Se(3), 113.7(3); C(19)–P(2)–Se(2), 95.7(3); C(13)–
˚
.71073 A. Reflections collected/unique = 5048/3549 [R(int) = 0.0211], final
0
R indices [I . 2s(I)] R1 = 0.0428, wR2 = 0.1092.
P(2)–Se(2), 107.0(3); Se(3)–P(2)–Se(2), 116.51(1).
2
180 | Chem. Commun., 2006, 2179–2181
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Crystal data for 2: C12
˚
C2/c, a = 20.905(8) A, b = 8.393(3) A, c = 11.592(4) A, a = 90,
H
28
P
2
Se , M
4
r
= 550.12, monoclinic, space group
6 A. M u¨ ller, P. Christophliemk and V. V. K. Rao, Chem. Ber., 1971, 104,
1905.
7 M. J. Pilkington, A. M. Z. Slawin, D. J. Williams and J. D. Woollins,
Polyhedron, 1991, 10, 2641.
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White and D. J. Williams, Inorg. Chem., 2004, 43, 4802.
9 W. W. du Mont, R. Hensel, W. Mcfarlane, I. J. Colquhoun,
M. L. Ziegler and O. Serhadli, Chem. Ber., 1989, 122, 37.
10 H. G. Horn and H. J. Lindner, Chem.-Ztg., 1985, 109, 77.
˚
˚
3
23
˚
b = 103.120(9), c = 90, V = 1980.8(12) A , Z = 4, rcalculated = 1.845 g cm
,
2
1
m = 7.556 mm , T = 100(2) K. Crystal size 0.20 6 0.15 6 0.08 mm,
˚
l = 0.71073 A. Reflections collected/unique = 8158/2319 [R(int) = 0.0292],
final R indices [I . 2s(I)] R1 = 0.0324, wR2 = 0.0669.
¯
= 607.22, triclinic, space group P1,
Crystal data for 3: C24
H
20
P
2
Se , M
3
r
˚
a = 9.279(3) A, b = 11.260(3) A, c = 13.075(4) A, a = 106.562(5),
˚
˚
3
˚
b = 100.360(5) , c = 110.862(4) , V = 1161.6(5) A , Z = 2 , rcalculated
=
2
3
21
1
0
0
.736 g cm , m = 4.896 mm , T = 100(2) K. Crystal size 0.20 6 0.20 6
1
1
1
1 H. G. Horn and H. J. Lindner, Chem.-Ztg., 1988, 112, 195.
2 R. A. Benkeser, Acc. Chem. Res., 1971, 4, 94.
3 W. W. du Mont, L. P. Muller, L. Muller, S. Vollbrecht and A. Zanin,
˚
.08 mm, l = 0.71073 A. Reflections collected/unique = 5822/4004 [R(int) =
.0211], final R indices [I . 2s(I)] R1 = 0.0622, wR2 = 0.1369.
J. Organomet. Chem., 1996, 521, 417.
14 C. Q. Nguyen, A. Adeogun, M. Afzaal, M. A. Malik and P. O’Brian,
Chem. Commun., 2006, DOI: 10.1039/b603198f.
15 G. M. Sheldrick, SHELXL-97, Program for refinement of crystal
structures, University of G o¨ ttingen, Germany, 1997; G. M. Sheldrick,
SHELXS-97, Program for solution of crystal structures, University of
G o¨ ttingen, Germany, 1997.
1
2
3
4
W. Kuchen and H. Hertel, Angew. Chem., Int. Ed. Engl., 1969, 8, 89.
W. Kuchen and B. Knop, Angew. Chem., Int. Ed. Engl., 1965, 4, 244.
W. Kuchen, J. Metten and A. Judat, Chem. Ber./Recl., 1964, 97, 2306.
A. M u¨ ller, V. V. K. Rao and P. Christophliemk, J. Inorg. Nucl. Chem.,
1
974, 36, 472.
A. M u¨ ller, P. Christophliemk and V. V. K. Rao, J. Inorg. Nucl. Chem.,
972, 34, 345.
5
1
16 Bruker, SHELXTL. Version 6.10, Bruker AXS Inc., 2000.
This journal is ß The Royal Society of Chemistry 2006
Chem. Commun., 2006, 2179–2181 | 2181