Chemoselective synthesis of first representatives of bis(diorganothiophosphinyl)selenides, (R2P=S)2Se, from secondary phosphine sulfides and elemental selenium

Article abstract of DOI:10.1016/j.inoche.2013.01.019

First bis(diorganothiophosphinyl)selenides, (R₂P = S) ₂Se, have been synthesized in 74-86% yield by the chemoselective interaction of secondary phosphine sulfides with elemental selenium (1:1 molar ratio, 100 C, 3 h, 1,4-dioxane); th

Full text of DOI:10.1016/j.inoche.2013.01.019

Inorganic Chemistry Communications 30 (2013) 124–127
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Inorganic Chemistry Communications
journal homepage: www.elsevier.com/locate/inoche
Chemoselective synthesis of first representatives of bis(diorganothiophosphinyl)
selenides, (R2P=S)2Se, from secondary phosphine sulfides and elemental selenium
Alexander V. Artem'ev a, Ludmila A. Oparina a, Nina K. Gusarova a, Nikita A. Kolyvanov a,
Oksana V. Vysotskaya a, Irina Yu. Bagryanskaya b, Boris A. Trofimov a,
⁎
a
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, 1 Favorsky Str., 664033 Irkutsk, Russian Federation
N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 9 Lavrentiev Ave., 630090 Novosibirsk, Russian Federation
b
a r t i c l e i n f o
a b s t r a c t
Article history:
First bis(diorganothiophosphinyl)selenides, (R2P=S)2Se, have been synthesized in 74–86% yield by the
chemoselective interaction of secondary phosphine sulfides with elemental selenium (1:1 molar ratio,
100 °C, 3 h, 1,4-dioxane); the alternative bis(diorganoselenophosphinyl)sulfides, (R2P=Se)2S, are not
formed under these conditions.
Received 3 August 2012
Accepted 23 January 2013
Available online 1 February 2013
© 2013 Elsevier B.V. All rights reserved.
Keywords:
Phosphine sulfides
Selenium
Selenides
Crystal structure
Thioselenophosphinate
Currently, the phosphonic acid anhydrides, i.e. bis(diorganophosphinyl)
oxides I, as well as their sulfur (II) and selenium (III) heteroanalogues
(Fig. 1) attract growing attention as ligands for metal complexes [1],
flame retardants [2], selenium sources for the fabrication of selenium-
containing nanoparticles [3], potential pharmaceuticals and agrochemicals
[4], promising accelerators for the vulcanisation of rubber [5] as well as
reagents and building blocks for organic synthesis [6].
For instance, bis(diorganoselenophosphinyl)selenides, (R2PSe)2Se
(III), were successfully applied for the preparation of highly demanded
Zn(II), Cd(II), Co(II), Ni(II), Pb(II), Ga(III), In(III) and Bi(III) diseleno-
phosphinates [1c,d,3] which are convenient single-source precursors for
the fabrication of metal selenides conductive nanomaterials via chemical
vapor deposition (CVD) route (Scheme 1).
In contrast, the mixed bis(diorganoselenophosphinyl)chalcogenides
IV–VI are much less studied [7], whereas their heteroanalogues VII–IX
are still unknown (Fig. 2). Meanwhile, these mixed chalcogenides are pro-
spective precursors to nano-sized semiconducting chalcogenides, poten-
tial drugs and agrochemicals, ligands for constructing of multi-purpose
metalcomplexes as well as promising reagents for the synthesis
of sulfur and selenium containing organophosphorous compounds.
Also, bis(diorganochalcogenophosphinyl)chalcogenides represent funda-
mental interest from the viewpoint of the structural chemistry
of heteroatom-containing competitively conjugated systems of
X_P\X\P_X type (X=O, S or Se).
Thus, synthesis and study of mixed bis(diorganochalcogenophosphinyl)
chalcogenides represent a recognized fundamental challenge in main
group inorganic chemistry. In an effort to address this issue, we have
synthesized the first representatives of bis(diorganothiophosphinyl)
selenides, (R2P=S)2Se, via unknown reaction of secondary phosphine
sulfides with elemental Se. It should be pointed out that the course of
this reaction is far from being obvious. Indeed, according to previous
studies on the interaction of secondary phosphine sulfides with sulfur
[8] (Scheme 2), reaction between R2P(S)H and Se should result in
the formation of the thioselenophosphinic acids, i.e. R2P(Se)SH,
R2P(S)SeH or their mixture. On the other hand, it is known [9],
that secondary phosphine selenides, R2P(Se)H, react with elemen-
tal Se to give selectively bis(diorganoselenophosphinyl)selenides
(no traces of the expected acids R2P(Se)SeH being detectable in
the reaction mixtures), Scheme 3.
Our experiments have shown, that the interaction of secondary phos-
phine sulfides 1a–e with elemental selenium in a 1:1 molar ratio gives
rise to the formation of earlier unknown bis(diorganothiophosphinyl)
selenides 2a–e in 74–86% isolated yield (Scheme 4) [10]. The reaction
O
O
Se Se
S
S
R
P
P
R
R
P
P
R
R
P
P
R
O
Se
S
R
R
R
R
R
R
I
II
III
⁎
Corresponding author. Tel.: +7 395242 14 11; fax: +7 395241 93 46.
E-mail address: boris_trofimov@irioch.irk.ru (B.A. Trofimov).
Fig. 1. Bis(diorganochalcogenophosphinyl)chalcogenides.
1387-7003/$ – see front matter © 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.inoche.2013.01.019

A.V. Artem'ev et al. / Inorganic Chemistry Communications 30 (2013) 124–127
125
Se Se
MCln /MeOH
1 h, r.t.
VD
C
MxSey
nanoparticles
R
P
P
R
M Se PR
(
)
2 n
2
Se
R
R
53-69%
M = Pb, Zn, Cd, Co, Ni, Ga, In, Bi
R = i-Pr, Ph n = 2 or 3
Scheme 1. Application of selenides III for production of metal selenides nanomaterials.
S
S
Se Se
O
O
proceeds in 1,4-dioxane at 100 °C for 3 h with high degree of
chemoselectivity: no the expected bis(diorganoselenophosphinyl)sul-
fides, (R2P=Se)2S, are formed (31P NMR).
Also, the release of H2Se as reaction by-product was detected by
color test with the Cd(OAc)2 solution. The energy dispersive X-ray
analysis of the resulting red precipitate showed the formation of
CdSe without admixture of CdS.
R
P
P
R
R
R
P
P
R
R
R
P
P
O
O
S
R
R
R
R
R
R
R
VI
IV
V
Se Se
O
O
S
S
Bis(diorganothiophosphinyl)selenides 2a–e are air-stable solids,
well soluble in common solvents such as benzene, 1,4-dioxane, chloro-
form and acetone. Interestingly, on contact with DMSO, these com-
pounds undergo oxidation to precipitate red selenium powder.
Selenides 2a–e have been characterized by 1H, 13C, 31P and 77Se
NMR as well as IR spectroscopy. In solution 31P NMR spectra of
bis(diorganothiophosphinyl)selenides, the resonance of two magneto-
equivalent phosphorus atoms is observed as sharp singlet at 71.53–
72.71 ppm (except for 2e, 98.49 ppm) flanked by single set of 77Se
P
P
R
R
P
P
R
R
P
P
R
S
Se
Se
IX
R
R
R
R
R
VIII
VII
Fig. 2. Mixed bis(diorganochalcogenophosphinyl)chalcogenides.
1
satellites with JPSe=361–378 Hz, indicating only P\Se bond present
in the each compound. Meanwhile, the solution 77Se NMR spectra
are comprised of a triplet at 212–294 ppm (1JPSe=361–378 Hz) due
to the splitting on two magneto-equivalent phosphorus atoms. As
expected, the solution 1H and 13C NMR spectra of selenides 2a–e were
confirming the presence of corresponding organo-groups connecting
with the phosphorus atoms. The presence of the P_S groups in com-
pounds 2a–e is supported by a strong bands at 602–608 cm−1 in
solid-state IR spectra.
80 oC, 6 h
S
R
R
R
S
+
P
S
P
benzene
R
H
SH
79-91%
R = Bu, i-Bu, Ph
Apparently, reaction pathway involves oxidation of corresponding
trivalent tautomeric form A of secondary phosphine sulfide 1 with el-
emental selenium. The resulting SH-acid B in its tautomeric SeH-form
C undergoes the intermolecular condensation eliminating H2Se to
give selenide 2 (Scheme 5). The possible intermolecular condensation
of SH-acid B with elimination of H2S does not take place, likely due to
the unfavorable cleavage of P\S bond in comparison with weaker P\Se
bond in acid C. This rationalization explains satisfactorily, why only
bis(diorganothiophosphinyl)selenides 2a–e were exclusively formed
and no possible bis(diorganoselenophosphinyl)sulfides, (R2P=Se)2S,
were detectable in the reaction mixtures.
The mechanism proposed is in compliance with our finding that the
reaction can be stopped at the acid B formation stage when the reaction
lasts 20–30 min only (Scheme 6). Eventually, thioselenophosphinic
S-acids 3a–e have been prepared in solution (1,4-dioxane) with minor
admixture of selenides 2a–e (up to 10%).
Scheme 2. Reaction of secondary phosphine sulfides with elemental sulfur.
Se
Se
80-85 oC, 3 h
toluene
R
R
Se
H
R
R
+
Se
P
P
P
Se
R
R
78-80%
R = Ph(CH2)2, 4-t-BuC6H4(CH2)2
Scheme 3. Reaction of secondary phosphine selenides with elemental selenium.
R
R
R
R
R
R
S
H
Se
Se
P
P
P
SH
SH
S
S
100 oC, 3 h
1,4-dioxane
R
R
S
H
R
R
1
A
B
+
Se
P
P
P
Se
R
R
S
S
R
R
Se
R
R
S
1a-e
P
2a-e (74-86%)
P
P
P
R
R
- H2Se
Se
SH
SeH
R
R
R = Ph(CH2)2 (a),4-ClC6H4(CH2)2 (b),
B
C
2
4-MeOC6H4(CH2)2 (c), 2-Furyl(CH2)2 (d), Cy(e)
Scheme 5. Plausible mechanistic pathway of the reaction between secondary phos-
phine sulfides 1 and elemental selenium.
Scheme 4. Chemoselective synthesis of bis(diorganothiophosphinyl)-selenides 2a–e.

126
A.V. Artem'ev et al. / Inorganic Chemistry Communications 30 (2013) 124–127
100 oC, 20-30 min
1,4-dioxane
R
R
Se
S
S
R
R
S
H
+
e
S
+
R
P
P
P
R
R
P
Se
SH
R
1a-e
3a-e
2a-e
R = Ph(CH2)2 (a), 4-ClC6H4(CH2)2 (b),
4-MeOC6H4(CH2)2 (c), 2-Furyl(CH2)2 (d), Cy (e)
ratio 9:1
Scheme 6. Synthesis of thioselenophosphinic S-acids 3a–e.
The SH-form of the acids 3a–e unambiguously follows from their
31P and 77Se NMR spectra that well agrees with the Murai's data on
preparation of similar acids, R2P(Se)SH, by acidification of their salts
[11]. Acids 3a–e were prepared only in solution state because their
isolation lead to the decomposition.
We have accidentally found that the storage of the above 1,4-dioxane
solution of acid 3e and selenide 2e (their ratio was ca. 9:1) in the presence
of air (4–6 °C, 2 days) gives the formation of co-crystals of selenide 2e
with corresponding diselenide, (Cy2P=S)2Se2 (4). We believe that the
diselenide 4 is produced via air oxidation of Cy2P(Se)SH. Apparently,
such oxidative coupling is triggered by the hydrogen (H•) transfer from
acid 3e by the action of oxygen (on air) to generate free radicals D,
which undertakes then selective recombination to form diselenide 4
(Scheme 7).
Fig. 3. X-ray structure of monoselenide 2e in the co-crystal (50% thermal ellipsoid). Se-
lected bond lengths [Å] and angles [°]: Se(1)–P(1) 2.3014(13); Se(1)–P(2) 2.2604(13);
S(1)–P(1) 2.0017(15); S(2)–P(2) 1.9862(15); P(1)–Se(1)–P(2) 107.88(4); Se(1)–
P(1)–S(1) 117.09(6); and Se(1)–P(2)–S(2) 103.33(5).
represent significant contributions to both phosphorus and chalcogen
The molecular structures of selenide 2e and diselenide 4 in co-crystal
have been determined by single-crystal X-ray diffraction analysis [12].
The S(1)–P(1)–Se(1)–P(2)–S(2) unit of selenide 2e has a syn-anti con-
formation (Fig. 3). Meanwhile, both S(3)–P(3)–Se(3)–Se(2) and S(4)–
P(4)–Se(2)–Se(3) units in diselenide 4 adopt syn conformation with
P(3)–Se(3)–Se(2)–P(4) dihedral angle of 94.82° (Fig. 4). The close con-
geners of diselenide 4, bis(5,5-dimethyl-2-thioxo-dioxaphosphorinan-
2-y1)diselenide [13], bis[6-O,6′-O-(1,2:3,4-diisopropylidene-R-D-
galactopyranosyl)dithuophosphoryl]diselenide [14], [Pht-BuP(S)]2Se2
[15] and [(t-BuCH2O)2P(S)]2Se2 [16], have the same conformation of
inorganic chemistry.
Acknowledgments
This work was supported by the Russian Foundation for Basic
Research (grant no. 11-03-00334-а) and the President of the Russian
Federation (program for the support of leading scientific schools,
grant NSh-1550.2012.3).
S_P\Se\Se\P_S chain. The Se\Se distance in diselenide
4
[2.3012(9) Å] fall close to the values found in the related diselenides
[13–16]. The coordination geometry around the phosphorus atoms in
2e and 4 is distorted from ideal tetrahedral geometry, apparently, due
to steric effects of the cyclohexyl groups. The single P\Se bond distances
[2.3014(13), 2.2604(13) Å for 2e, and 2.3199(13), 2.3054(14) Å for 4]
are similar to those in other compounds containing the P(V)-Se unit
[17]. Likewise, all the P_S bond distances in the range of 1.9712(15)–
2.0017(15) Å are comparable with the literature values reported for com-
pounds bearing P_S bonds [18]. It should be noted, that the shortest Se…
Se intermolecular contacts exist between diselenide molecules in
co-crystal as evident from the Se(3)…Se(3) distance of 3.479 Å, which
is significantly less than the sum of the van der Waals radii of Se (3.80 Å).
In summary, first representatives of bis(diorganothiophosphinyl)
selenides have been synthesized in high yield via unknown reaction
of secondary phosphine sulfides and selenium. The reaction proceeds
chemoselectively and opens rewording opportunities for systematic
studies of bis(diorganothiophosphinyl)selenides, which are promis-
ing building blocks for organic synthesis, versatile ligands for metal
clusters as well as precursors for drugs and agrochemicals. The result
Appendix A. Supplementary material
Supplementary data (general experimental methods, synthetic
procedures, crystallographic details, and analytical data for the syn-
thesized compounds) to this article can be found online at http://
dx.doi.org/10.1016/j.inoche.2013.01.019.
Cy
S
P
Cy
Cy
Se
Cy
Cy
Se
S
recombination
O2
Cy
Se
P
P
P
Se
Cy
SH
Fig. 4. X-ray structure of diselenide 4 in the co-crystal (50% thermal ellipsoid). Selected
bond lengths [Å] and angles [°]: Se(2)–Se(3) 2.3012(9); Se(2)–P(4) 2.3199(13);
Se(3)–P(3) 2.3054(14); S(3)–P(3) 1.9830(15); S(4)–P(4) 1.9712(15); Se(3)–Se(2)–
P(4) 100.40(3); Se(2)–Se(3)–P(3) 104.75(3); Se(3)–P(3)–S(3) 115.25(6); and Se(2)–
P(4)–S(4) 115.48(6).
S
Cy
3e
D
4
Scheme 7. Formation of diselenide 4 via two-electron oxidation of S-acid 3e.

A.V. Artem'ev et al. / Inorganic Chemistry Communications 30 (2013) 124–127
127
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