The reaction of [Os6(CO)18] with [(SPPh 2)2NH]: Facile rearrangement of the metal framework

Article abstract of DOI:10.1016/j.ica.2010.03.055

The reaction of [Os₆(CO)₁₈] 1 with [(SPPh ₂)₂NH] in the presence of Me₃NO produces a purple compound characterized spectroscopically and by X-ray crystallography, as [HOs₆(CO)₁₇(SPPh₂)₂N] 2. The structure shows the hexanuclear fragment to have suffered a geometrical rearrangement to give a metal framework that can be described as an edge-bridged tetrahedron with an additional terminal osmium atom bonded to one of the bridged metal atoms. The ligand acts as a bimetallic tetraconnective unit through both sulphur atoms between two non-bonded osmium atoms.

Full text of DOI:10.1016/j.ica.2010.03.055

Inorganica Chimica Acta 363 (2010) 2661–2663
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Note
The reaction of [Os (CO) ] with [(SPPh ) NH]: Facile rearrangement
6
18
2 2
of the metal framework
Karina Dominguez-Guzman , Ana L. Carrasco , Marco A. Leyva , María J. Rosales-Hoz , Ionel Haiduc b,
Cristian Silvestru
a
a
a
a
a,*
b
Departamento de Química, Centro de Investigación y de Estudios Avanzados del I. P. N. Av. Instituto Politécnico Nacional 2508, Col. San Pedro Zacatenco, México 07360 D. F., Mexico
Facultatea de Chimie si Inginerie Chmica, Universitatea Babes-Bolyai, RO-400028 Cluj-Napoca, Romania
b
a r t i c l e i n f o
a b s t r a c t
Article history:
The reaction of [Os (CO) ] 1 with [(SPPh ) NH] in the presence of Me NO produces a purple compound
6
18
2 2
3
Received 15 January 2010
Accepted 19 March 2010
Available online 27 March 2010
6 2 2
characterized spectroscopically and by X-ray crystallography, as [HOs (CO)17(SPPh ) N] 2. The structure
shows the hexanuclear fragment to have suffered a geometrical rearrangement to give a metal frame-
work that can be described as an edge-bridged tetrahedron with an additional terminal osmium atom
bonded to one of the bridged metal atoms. The ligand acts as a bimetallic tetraconnective unit through
both sulphur atoms between two non-bonded osmium atoms.
Keywords:
Osmium clusters
X-ray structures
Ó 2010 Elsevier B.V. All rights reserved.
Iminobis(diphenylphosphinechalcogenide)
Hexanuclear
1
. Introduction
nmr spectrum shows two doublet resonances at d 29.9 and
2
3
7.1 ppm with JPP = 5.4 Hz.
The coordination chemistry of iminobis(diphenylphosphine-
The molecular structure of 2, together with selected bond
chalcogenide) ligands has attracted considerable attention over
the years [1,2]. The interaction of this type of ligand with tran-
sition metal carbonyl clusters has also been explored [3–5] and
shown to produce both compounds where the ligand coordinates
to the metal framework through the chalcogen atoms [3] and
derivatives where the P = E (E = chalcogen) bonds suffer a cleav-
age [4,5]. However, the studies have only been carried out using
trinuclear metal clusters and no studies with high nuclearity
clusters have been described. Such high nuclearity clusters have
shown higher versatility since they offer the possibility of geo-
metric rearrangements besides the diverse coordination modes
that the ligands can adopt [6].
lengths and angles, is shown in Fig. 1. The bicapped tetrahedral
structure of 1 opens up to form a structure with a tetrahedron
formed by Os(1), Os(2), Os(5) and Os(6), with the Os(1)–Os(2) edge
bridged by the Os(3) atom, and a sixth osmium atom, Os(4),
bonded only to Os(1). The two sulphur atoms of the ligand unit
are bridging between Os(3) and Os(4). There are two Os–Os bonds
which are significantly longer than the rest: Os(1)–Os(4)
2.9594(3) Å and Os(2)–Os(6) 2.9670(3) Å. This last bond is bridged
by the hydride group which was located in a difference map.
The ligand-bridged spiked metal geometry has been observed
previously in several cases [7–9], but in 2 the ligand is bridging,
in a bimetallic tetraconnective fashion, two metal atoms which
are not bonded directly. A similar coordination pattern of the
deprotonated phosphorus ligand was observed in the related trinu-
2
. Results and discussion
3 9 2 2
clear compound [HOs (CO) (SPPh ) N] 3 [3]. The lack of a ligand
bridging the spiked bond, might be the cause of the large Os(1)–
Os(4) distance of 2.9594(3) Å. The sulphur atoms are not bonded
to the metal atoms in a symmetrical fashion. For both sulphur
atoms one of the bonds is around 0.043 Å longer than the other
one. This contrasts with the behaviour reported for the trinuclear
The reaction of [Os
of Me
NO at ꢀ78 °C, gives a deep purple compound of formula
HOs (CO)17(SPPh N] 2 (Scheme 1) in a 70% yield together with
some recovered starting material and [Os
spectrum for this compound shows, in addition to signals at d
.6–7.9 ppm for the aromatic protons, resonance at
6 2 2
(CO)18] 1 with [(SPPh ) NH] in the presence
3
[
6
2 2
)
1
3
(CO)12]. The H nmr
3 9 2 2 3 2 2
derivatives [HOs (CO) (SPPh ) N] 3 or [Os (CO)10{(SPPh ) NH}] 4,
7
a
d
19.3 ppm indicating the presence of a hydride group. The 31P
in which both the protonated and the deprotonated exhibit a basi-
cally symmetrical bimetallic tetraconnective coordination pattern.
There are no significant differences in P–S and P–N bond dis-
tances when compared with those of complex 3 or 4. However, a
ꢀ
*
Corresponding author.
E-mail address: mrosales@cinvestav.mx (M.J. Rosales-Hoz).
0
020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.03.055

2
662
K. Dominguez-Guzman et al. / Inorganica Chimica Acta 363 (2010) 2661–2663
Scheme 1.
comparison with the molecular parameters in the free (SPPh
2
)
2
NH
This flexibility has shown to be important in the activation of some
ring-opening processes [11], a behaviour that could be important
in catalysis.
[
P–S 1.950(1)/1.937(1) Å; P–N 1.672(2)/1.683(2) Å] [10] suggests a
single P–S and double PN bond character in the title compound.
The SPNPS ligand skeleton is almost planar and forms a dihedral
angle of 87° with the Os(3)Os(1)Os(4) plane. The Os(3)–Os(1)–
Os(4) angle [68.7(3)°] is smaller than in compounds 3 [70.57(7)°]
or 4 [73.24(4)°]. The P(1)N(1)P(2) angle [134.0(4)°] in 2 is similar
to that in 3 [134(2)°], but smaller than in 4 [137(1)°], which con-
tains the protonated ligand [3].
Compound 2 is very stable even when heated to 100 °C in a tol-
uene. The cleavage of the P@S bond observed in the trinuclear
ruthenium cluster derivatives [5] is not observed here.
3
. Conclusions
6
The reaction of Os (CO)18 with the phosphineamine ligand
(
2 2
SPPh ) NH produces, under mild conditions and in a relatively
high yield; coordination of the ligand through the two sulphur
atoms substituting only one carbonyl group and by an opening of
the metal framework through cleavage of metal-metal bonds.
High nuclearity clusters have shown that transformations on
the geometry of the metal framework are easily accomplished in
order to adapt to the electronic requirements of the ligand used.
4
. Experimental
6 2 2
The compounds [Os (CO)18] and [(SPPh ) NH] were prepared by
literature procedures [12,13]. The reaction and other manipula-
tions were carried out under nitrogen atmosphere using standard
Schlenk techniques. Solvents were dried and distilled under a
nitrogen atmosphere prior to use. The infrared spectrum was re-
corded in a Perkin–Elmer 16F spectrometer. NMR spectra were ob-
tained in a Jeol Eclipse 400 spectrometer using SiMe
4
and external
H
3
PO as references. The mass spectrum was obtained in a FAB-
4
Jeol SX-102A mass spectrometer. The X-ray crystal structure data
was measured in an Enraf-Nonius Kappa CCD diffractometer. Some
crystallographic data is given in Table 1.
The structure was solved by direct methods (SHELXS-97) [14], and
Fourier difference techniques. Full-matrix least-squares refine-
2
ment on F . Non-hydrogen atoms were refined anisotropically.
Synthesis of [HOs
solved in 100 ml of dichloromethane; (PPh
added; the mixture was stirred and cooled down to ꢀ78 °C. Once
the solution reaches the desired temperature, a solution of Me NO
2.06 mg) is slowly added to the mixture. Once the addition is fin-
6
(CO)17(SPPh
)
2 2
6
N], 2. Os (CO)18 (30 mg) is dis-
2
2
S) NH (8.19 mg) is
3
(
ished, the mixture is left to reach room temperature. Once the sol-
vent was evaporated under vacuum the mixture was separated by
thin layer chromatography. Single crystals of 2 were obtained by
slow evaporation of a CH
2
Cl
2
-hexane solution. Spectroscopic data:
ꢀ1
IR [
3
054(w), 2040(s), 2028(s), 1994(m), 1968(w). H NMR (CDCl ): d
m(CO), cm ] (CH Cl ): 2126(m), 2128(m), 2092(m), 2068(s),
2 2
1
2
Table 1
Crystal data for compound 2.
Empirical formula
Formula weight
Crystal system
Space group
41 6 2 2 2 2 2
C H21NO17Os P S CH Cl 3H O
2205.82
monoclinic
P21/c
Cell dimensions
0
1
2
2
3.5229(1)
0.0943(2)
1.5222(3)
a ( ÅA )
0
b ( AÅ )
0
Fig. 1. Molecular structure of complex 2. Some selected bond lengths (Å) and angles
c ( AÅ )
b (°0)
(
deg.): Os(1)–Os(2) 2.8395(3), Os(1)–Os(3) 2.9011(3), Os(1)–Os(4) 2.9594(4),
Os(1)–Os(5) 2.8408(4), Os(1)–Os(6) 2.8554(3), Os(2)–Os(3) 2.8231(4), Os(2)–Os(5)
.8307(2), Os(2)–Os(6) 2.9670(3), Os(3)–S(1) 2.4982(3), Os(3)–S(2) 2.4028(3),
Os(4)–S(1) 2.4544(3), Os(4)–S(2) 2.4463(2), P(1)–S(1) 2.0886(3), P(2)–S(2)
.0874(3), N(1)–P(1) 1.586(7), N(1)–P(2) 1.579(7), Os(4)–Os(1)–Os(3) 68.7(3),
Os(4)–S(1)–Os(3) 83.8(3), Os(4)–S(2)–Os(3) 86.0(3), P(1)–N(1)–P(2) 134.0(4).
103.10(1)
5696.10(1)
3
V ( AÅ )
2
Z
D
4
calc (Mg/m3)
2.572
2
Final R indices [F > 4
r(F)]
1 2
R = 0.0384, wR = 0.0843

K. Dominguez-Guzman et al. / Inorganica Chimica Acta 363 (2010) 2661–2663
2663
ꢀ
19.3 ppm. 31P NMR (CDCl
PP = 5.4 Hz). FAB mass spectrum: m/z 2066.
3
): d 29.9 (d, 2
J
PP = 5.4 Hz) and 37.1 (d,
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