Synthesis and structure of the clusters [Hg2(μ-SePh) 2(SePh)2(PPh3)2] and [Hg 3Br3(μ-SePh)3]·2 DMSO

Article abstract of DOI:10.1002/zaac.200300372

The compounds [Hg₂(μ-SePh)₂(SePh) ₂(PPh₃)2] (I) and [Hg₃Br₃(μ-SePh) ₃]·2 DMSO (II) are formed by reactions of [Hg(SePh) ₂] with PPh₃ in THF(I) or with HgBr₂ in DMSO (II) at room temperature. X-ray crystallography reveals that the cluster I consists of a distorted square built by each two Hg and Se atoms. The Hg atoms have almost tetrahedral co-ordination environments formed by selenium atoms of two (μ-^-SePh) ligands and Se and P atoms of terminal ^-SePh and PPh₃ ligands. The compound II is a six-membered ring with alternating Hg and Se atoms in the chair conformation. Two DMSO molecules occupy positions below and above the [Hg₃Se₃] ring with the oxygen atoms directed to the centre of the ring.

Full text of DOI:10.1002/zaac.200300372

Synthesis and Structure of the Clusters
[Hg2(µ؊SePh)2(SePh)2(PPh3)2] and [Hg3Br3(µ؊SePh)3] · 2 DMSO
a,
a
a
b
´
´
Ernesto Schulz Lang *, Marcelo Müller Dias , Sailer Santos dos Santos , Ezequiel M. Vazquez-Lopez , and
Ulrich Abramc
a
´
ˆ
Santa Maria / Brazil, Laboratorio de Materiais Inorganicos Ϫ Universidade Federal de Santa Maria
b
´
´
´
Vigo, Galicia / Spain, Departamento de Quımica Inorganica, Facultade de CienciasϪQuımica, Universidade de Vigo
c Berlin / Germany, Institut für Chemie der Freien Universität
Received November 26th, 2003.
Abstract. The compounds [Hg2(µϪSePh)2(SePh)2(PPh3)2] (I) and
[Hg3Br3(µϪSePh)3] · 2 DMSO (II) are formed by reactions of
[Hg(SePh)2] with PPh3 in THF(I) or with HgBr2 in DMSO (II) at
room temperature. XϪray crystallography reveals that the cluster I
consists of a distorted square built by each two Hg and Se atoms.
The Hg atoms have almost tetrahedral co-ordination environments
formed by selenium atoms of two (µ-ϪSePh) ligands and Se and P
atoms of terminal ϪSePh and PPh3 ligands. The compound II is a
six-membered ring with alternating Hg and Se atoms in the chair
conformation. Two DMSO molecules occupy positions below and
above the [Hg3Se3] ring with the oxygen atoms directed to the cen-
tre of the ring.
Keywords: Selenium; Organoselenium compounds; Secondary
bonds; Crystal structure
Synthese und Strukturen der Cluster [Hg2(µ؊SePh)2(SePh)2(PPh3)2] und
[Hg3Br3(µ؊SePh)3] · 2 DMSO
Inhaltsübersicht. Die Clusterverbindungen [Hg2(µ-SePh)2(SePh)2-
(PPh3)2] (I) and [Hg3Br3(µ-SePh)3] · 2 DMSO (II) entstehen bei
Reaktionen von [Hg(SePh)2] mit PPh3 in THF (I) bzw. mit HgBr2
in DMSO (II). Die Strukturen der Produkte wurden kristallogra-
phisch aufgeklärt. Das Zentrum von [Hg2(µ-SePh)2(SePh)2(PPh3)2]
besteht aus einem verzerrten Quadrat aus zwei Hg- und zwei Se-
Atomen. Die Quecksilberatome sind nahezu tetraedrisch koordi-
niert. Ihre Koordinationssphäre wird aus den Se-Atomen zweier
(µ-ϪSePh)-Liganden und den Se und P-Atomen terminaler ϪSePh-
und PPh3-Einheiten gebildet. Die Verbindung II besteht aus einem
sechsgliedrigen Ring, in dem alternierend Hg- und Se-Atome an-
geordnet sind. Oberhalb und unterhalb der Ringebene sind
DMSO-Moleküle angeordnet, deren Sauerstoffatome in Richtung
der Ringebene weisen.
Introduction
can be used to generate some ligands for the synthesis “in
situ” [5].
Mercury chalcogenide compounds have found considerable
use in industry, especially as low gap semiconductors, in
photovoltaic applications, and IR detection devices [1].
Thin films of metal chalcogenides are also of great interest
in the field of photovoltaics, where the metal chalcogenide
is deposited as films on glass, ceramic, and plastic surfaces
from a homogeneous solution by chemical deposition [2].
Thus, the control of the synthesis and molecular structure
of metal chalcogenide is of considerable interest in both
processes [3]. Compounds such as [M(ER)2] (M ϭ Zn, Cd,
Hg; E ϭ Se, Te; R ϭ alkyl or aryl), which have all of the
constituent of the product incorporated in a single molecule
are called “single-source” compounds [4]. These offer ad-
vantages such as better control of the reaction stoichi-
ometry and lower reaction temperatures. Additionally, they
Mercury selenides form interesting compounds by inter-
action with lanthanide chalcogenates [6] or based on
[Hg(SeR)2] units [7] as has been shown for reactions of
HgCl2 with PtBu3 and PhSeSiMe3 which yield the mercury
clusters [Hg6(SePh)12(PtBu3)2] and (HPtBu3)2[Hg6(SePh)14]
constituted by similar Hg-Se cages with distorted tetra-
hedral coordination around mercury atoms [7b]. [Hg(ER)2]
(EϭS, Se) reacts with equimolar amounts of HgCl2 in pyri-
dine to yield metallacyclic compounds of the type
t
[Hg4Cl4(µϪER)4(py)n] (EϭS, Rϭ Bu, nϭ2 [8]; EϭSe, Rϭ
t
Et, nϭ4; EϭSe, Rϭ Bu, nϭ4 [9]) and we found that the
corresponding tellurides afford under similar conditions the
clusters
(µϪTePh)3]
[Hg6(µϪBr)2Br2(µ2ϪTePh)8(py)2],
DMSO (XϭCl, Br, I) [10], and
[Hg3X3-
· 2
[Hg8(µϪnϪC3H7Te)12(µ2ϪBr)Br3] [11]. The presence of the
co-ordinating solvents and the sterical requirements of the
organic residues bonded to the chalcogen atoms are con-
sidered to be limiting parameters in the linking mode of the
ligands and the size of the clusters. Although the structure
of [Hg(SePh)2] has been recently reported [12], its reactivity
is only scarcely explored. This is probably due to the tend-
* Prof. Dr. Ernesto Schulz Lang
Universidade Federal de Santa Maria
Departamento de Quimica
97119-900 Santa Maria, RS, Brazil
email:eslang@base.ufsm.br
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DOI: 10.1002/zaac.200300372
Z. Anorg. Allg. Chem. 2004, 630, 462Ϫ465

[Hg2(µϪSePh)2(SePh)2(PPh3)2] and [Hg3Br3(µϪSePh)3] · 2 DMSO
ency of the compound to deposite mercury and to form
(SePh)2. However, bearing in mind the stabilizing effect of
DMSO or other donor solvents to mercury chalcogenides,
here we verify the influence of the nature of the chalcogen
atom on the reactivity following a similar procedure as has
previously
been
used
for
the
synthesis
of
telluriumϪmercury clusters [10, 11].
Results and Discussion
In clear contrast to the tellurium analogue, the reactivity of
[Hg(SePh)2] is limited by its tendency to deposit mercury
under formation of (SePh)2. The mercury(II) cation is stabi-
lized by addition of a slight excess of selenolate to form the
anionic complex [Hg(SePh)3]Ϫ [12]. The reaction of
[Hg(SePh)2]
with
triphenylphosphine
affords
[Hg2(µϪSePh)2(SePh)2(PPh3)2] (I) (Scheme I). The com-
pound is air-stable and soluble in DMSO, dioxane and di-
ethylether. As its tellurium analogue, [Hg(SePh)2] reacts
with HgBr2 in DMSO to form a 6-membered ring system,
[Hg3Br3(µϪSePh)3] · 2DMSO (II). However, I does not
form metallacyclic species when it reacts with the Lewis
acids HgX2 but forms the known compounds PhSeHgX
[13].
Fig. 1 Ellipsoid representation of the molecular structure of
[Hg2(µϪSePh)2(SePh)2(PPh3)2] (I).
˚
Table 1 Selected bond lengths /A and angles /° for
[Hg2(µϪSePh)2(SePh)2(PPh3)2] (I).
Hg-Se(1)
Hg-P(1)
Hg-Se(2)
Hg-Se(2)Ј
Se(2)-HgЈ
2.544(1)
2.556(1)
2.657(1)
2.819(1)
2.819(7)
Se(1)-Hg-P(1)
Se(1)-Hg-Se(2)
P(1)-Hg-Se(2)
Se(1)-Hg-Se(2)Ј
P(1)-Hg-Se(2)Ј
Se(2)-Hg-Se(2)Ј
Hg-Se(2)-HgЈ
118.27(4)
121.51(2)
103.33(3)
109.15(2)
106.34(4)
95.06(2)
84.94(2)
Crystals of I suitable for X-ray analysis could be obtained
from the reaction mixture. An ellipsoid representation [14]
of the molecular structure is shown in Figure 1. The struc-
ture can be described as constituted by two mercury atoms
which are asymmetrically bridged by two ϪSePh ligands.
The co-ordination spheres of the Hg atoms are completed
by two terminal ϪSePh and PPh3 ligands. The asymmetric
unit of the structure contains a half molecule of I and inver-
sion symmetry centre completes the four-membered ring,
with alternating Hg and Se atoms. The co-ordination
around the mercury atom is a distorted HgPSe3tetrahedron,
main distortions are due to the Se(1)-Hg(1)-Se(2) and Se(2)-
Hg(1)-Se(2)#1 angles of 121.51(2) and 95.06(2)°, respec-
Symmetry transformations used to generate equivalent atoms: Ј Ϫxϩ2,
Ϫyϩ1, Ϫzϩ1
˚
(3.4985(4) A) is intermediate between the two values ob-
˚
served in the methyl derivative (3.538(1) and 4.070(2) A) but
clearly shorter than in [Hg(SePh)2] (4.672(1) A) [12].
˚
The X-ray crystallographic analysis of II shows that the
structure is isotypic with the tellurium analogues
[Hg3X3(µϪTePh)3] · 2 DMSO (X ϭ Cl, Br, ) [10], and it
consists of molecules based on six-membered rings with
alternating Hg and Se atoms in a chair conformation (Fig.
2) and a terminal bromine atom co-ordinates to each mer-
cury atom. The HgϪSe distances (Table 2) are shorter than
the corresponding values for the bridging ϪSePh unit in I
(vide supra) and the phenylselenolato ligand in II forms al-
most symmetric bridges. The HgϪBr distances are close to
those found in [Hg3Br3(µϪTePh)3] · 2 DMSO [10]. Con-
sidering only the interactions noted above, the coordination
around the mercury atom would be trigonal-planar. How-
ever, as observed in the tellurium derivatives, there are two
dimethylsulfoxide molecules occupying positions on either
side of the Hg3Se3 ring with the oxygen atoms oriented to
˚
tively. The HgϪP bond (2.5563(14) A) is in the expected
range [15], but the HgϪSe bond lengths (2.544(1)Ϫ
˚
2.819(1) A) are clearly longer than those found in
[Hg(SePh)2] (2.471(2) A) and [Hg((SePh)3]Ϫ (2.600(2)-
˚
˚
2.536(1) A) [12]. More bond lengths and angles are con-
tained in Table 1. The strong asymmetry of the phenylselen-
olato bridges is obvious when compared with the structure
of [Hg(SeMe)2]n, which also contains a four-membered ring
formed by ϪSeMe bridges between two Hg atoms and
where the Hg-Se bond lengths range between 2.614(2) and
˚
2.764(2) A) [9]. Furthermore, the Hg-Hg distance in I
Z. Anorg. Allg. Chem. 2004, 630, 462Ϫ465
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 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
463

´
´
E. Schulz Lang, M. Müller Dias, S. Santos dos Santos, E. M. Vazquez-Lopez, U. Abram
˚
Table 2 Bond lengths /A and angles /° for [Hg3Br3(µϪSePh)3] · 2
DMSO (II).
Se(1)-Hg(1)
Se(1)-Hg(2)
Se(2)-Hg(2)
Se(2)-Hg(3)
Se(3)-Hg(3)
Se(3)-Hg(1)
Hg(1)-Br(1)
Hg(1)-Br(1)Ј
Hg(2)-Br(2)
Hg(3)-Br(3)
Br(1)-Hg(1)Ј
2.536(2)
2.577(2)
2.533(2)
2.571(2)
2.547(2)
2.563(2)
2.609(2)
3.134(2)
2.606(2)
2.575(2)
3.134(2)
Hg(1)-Se(1)-Hg(2)
Hg(2)-Se(2)-Hg(3)
Hg(3)-Se(3)-Hg(1)
Se(1)-Hg(1)-Se(3)
Se(1)-Hg(1)-Br(1)
Se(3)-Hg(1)-Br(1)
Se(1)-Hg(1)-Br(1)Ј
Se(3)-Hg(1)-Br(1)Ј
Br(1)-Hg(1)-Br(1)Ј
Se(2)-Hg(2)-Se(1)
Se(2)-Hg(2)-Br(2)
Se(1)-Hg(2)-Br(2)
Se(3)-Hg(3)-Se(2)
Se(3)-Hg(3)-Br(3)
Se(2)-Hg(3)-Br(3)
Hg(1)-Br(1)-Hg(1)Ј
95.42(5)
95.11(5)
96.27(5)
132.03(5)
120.17(5)
107.65(5)
93.72(5)
89.54(5)
90.17(5)
130.58(5)
121.63(6)
107.79(6)
128.63(5)
121.25(6)
110.06(6)
89.83(5)
Fig. 2 Ellipsoid representation of [Hg3Br3(µϪSePh)3] · 2 DMSO
(II). Weak O···Hg interactions (distances of about 3 A) are indica-
ted as dashed lines.
˚
Symmetry transformations used to generate equivalent atoms: Ј Ϫx, Ϫy,
Ϫzϩ1
the centre of the ring. The Hg-O distances are shorter than
the sum of their van der Waals radii [16]. The mercury
atoms interact weakly with the bromine atoms of the neigh-
Table 3 Crystal data and structure refinements.
I
II
bouring
molecules
[Hg(1)···Br(1)Ј
ϭ
3.134(2),
˚
Hg(2)···Br(2)Љ ϭ 3.164(2), Hg(3)···Br(3)ٞ ϭ 3.329(2) A
(symmetry operations: (Ј) xϩ1, Ϫyϩ1, Ϫz; (Љ) Ϫxϩ1,
Ϫyϩ1, Ϫzϩ1; (ٞ) Ϫxϩ1, Ϫy, Ϫzϩ1). If all weak interac-
tions are considered, the resulting co-ordination poly-
hedron around the mercury atom can be described as a
strongly distorted octahedron, while the co-ordination
around the selenium atom is trigonal-pyramidal with Hg-
Se-Hg angles around 95°.
Empirical formula
Formula weight
T / K
C60H50Hg2P2Se4
1549.96
C22H27Br3Hg3O2S2Se3
525.01
293(2)
0.71073 A
triclinic, P1
293(2)
0.71073 A
˚
˚
˚
Wavelength/ A
¯
¯
Crystal system,
space group
triclinic, P1
˚
a / A
9.829(2)
11.669(6)
14.092(2)
64.86(1)
77.66(1)
72.86(1)
1390.8(8)
1
10.155(2)
14.053(3)
14.404(3)
61.04(1)
72.67(1)
89.53(1)
1694.0(6)
2
˚
b / A
˚
c / A
α / °
β / °
γ / °
3
˚
V / A
Experimental Section
Z
ρcalc / g cm3
µ / mmϪ1
Crystal size/mm3
θ range / °
Limiting indices
1.851
8.224
2.874
20.464
Triphenylphosphine (Aldrich) and mercury(II) bromide (Fluka)
were used as received. [Hg(SePh)2] was synthezised by a reported
0.3 · 0.13 · 0.13
2.18Ϫ25.47
Ϫ11ՅhՅ11
Ϫ14ՅkՅ12
Ϫ17ՅlՅ0
5367
0.13 · 0.12 · 0.10
2.47Ϫ24.97
Ϫ12ՅhՅ12
0ՅkՅ16
Ϫ14ՅlՅ17
6203
´
method [12]. Melting points were determined on a Micro Quımica
APF 301 apparatus and were uncorrected.
Refl. Collected
Refl. Unique (Rint
Refl. Observed [I >2σ(I)]
Goodness-of-fit on F2
R1 (observed data)
wR2 (all data)
)
5141 (0.0189)
3970
1.023
0.0250
0.0562
5940 (0.0618)
4288
1.023
0.0480
0.0880
X-ray data collection, structures solution and
refinement.
The X-ray data have been collected at an automated CAD4 dif-
fractometer (Enraf Nonius). The structures were solved by direct
methods (SHELXSϪ97 [17]). All refinements were made by
fullϪmatrix leastϪsquares on F2 with anisotropic displacement
parameters for all non hydrogen atoms (SHELXLϪ97 [17]). Hy-
drogen atoms positions for I have been taken from the Fourier map
and refined, and for II they have been calculated for idealized posi-
tions and treated with the ’riding model’ option of SHELXL. Crys-
tal data and some relevant structure refinement parameters are
listed in Table 3. Further details of the crystal structure determi-
3
˚
Largest peak/hole / e A
0.532/ Ϫ0.671
1.897/ Ϫ1.869
nation are available free of charge via www.ccdc.cam.ac.uk/conts/re-
trieving.html (or from the CCDC, 12 Union Road, Cambridge CB2
1EZ, UK; fax: ϩ44 1223 336033; e-mail: deposit@ccdc.cam.ac.uk)
as
Supplementary
publication
Nos.
CSD
220807
([Hg2(µϪSePh)2(SePh)2(PPh3)2]), CSD 220808 ([Hg3Br3(µϪSePh)3]
· 2 DMSO).
464
 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
zaac.wiley-vch.de
Z. Anorg. Allg. Chem. 2004, 630, 462Ϫ465

[Hg2(µϪSePh)2(SePh)2(PPh3)2] and [Hg3Br3(µϪSePh)3] · 2 DMSO
[5] E. S. Lang, C. C. Gatto, U. Abram, Z. Anorg. Allg. Chem.
2002, 628, 335.
[6] M. Bernardini, T. J. Emge, J. G. Brennan, Inorg. Chem. 1995,
Preparation of [Hg2(µϪSePh)2(SePh)2(PPh3)2]
(I):
34, 5327.
[Hg(SePh)2] (0.512 g, 1 mmol) and PPh3 (0.262 g, 1 mmol) were
[7] (a) S. Behrens, M. Bettenhausen, A. C. Devenson, A.
Eichhöfer, D. Fenske, A. Lohde, H. Woggon, Angew. Chem.
1996, 108, 2360; Angew. Chem., Int. Ed. Engl. 1996, 35, 2215.
(b) M. Bettenhausen, D. Fenske, Z. Anorg. Allg. Chem. 1998,
624, 1245.
dissolved in THF and heated under reflux for
1 h. Pure
[Hg2(µϪSePh)2(SePh)2(PPh3)2] was obtained as pale yellow crystals
upon slow evaporation of the resulting solution under nitrogen.
Yield: 0.472 g, 61 %. M.p. 124°C. Anal. Found: C, 41.25; H, 3.1 %.
Calcd. for C60H50Hg2P2Se4: C, 42.19; H, 2.95 %.
[8] A. J. Canty, C. L. Raston, A. H. White, Aust. J. Chem. 1978,
31, 677. See also for the 4-metylpyridine derivative: A. J.
Canty, C. L. Raston, A. H. White, Aust. J. Chem. 1979, 72,
311.
[9] A. P. Arnold, A. J. Canty, B. W. Skelton, A. H. White, J. Chem.
Soc., Dalton Trans. 1982, 607.
[10] E. Schulz Lang, R. A. Zan, C. C. Gatto, R. A. Burrow, E. M.
Preparation of [Hg3Br3(µϪSePh)3] · 2 DMSO (II): [Hg(SePh)2]
(0.52 g, 1 mmol) and HgBr2 (0.360 g, 1 mmol) were dissolved in
10 ml of DMSO and the mixture was stirred for 3 h at room tem-
perature. The solution was over-layered with ethyl acetate (5 ml) to
give after 3 days pale yellow crystals. Yield: 1.0 g, 68 %. M.p.
208 °C. Anal. Found: C, 17.7; H, 1.5 %. Calc.: C, 16.5; H, 1.1 %.
´
´
Vazquez-Lopez, Eur. J. Inorg. Chem. 2002, 331.
[11] E. S. Lang, C. Peppe, R. A. Zan, U. Abram, E. M. Vazquez-
The authors gratefully acknowledge financial support from MCT/
CNPq and DAAD/CAPES. E.S.L. thanks the University of Vigo
(Spain) for a travel grant.
´
´
Lopez, B. Krumm, O. P. Ruscitti, Z. Anorg. Allg. Chem. 2002,
628, 2815.
´
´
[12] E. Schulz Lang, M. M. Dias, U. Abram, E. M. Vazquez-Lo-
pez, Z. Anorg. Allg. Chem. 2000, 626, 784 and references
cited therein.
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Z. Anorg. Allg. Chem. 2004, 630, 462Ϫ465
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 2004 WILEY-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim
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