Oxidative addition of Ph3SnH to Pt3(μ-CO) 3(PR3)3 (R=PCy3, P tBu3)

Article abstract of DOI:10.1016/j.inoche.2004.06.004

The oxidative addition of 1 equiv. of Ph₃SnH to Pt ₃(μ-CO)₃(PCy₃)₃ affords the triangular cluster [Pt₃(μ-CO)₃(PCy₃) ₃(Ph₃Sn)H] (1). The same reac

Full text of DOI:10.1016/j.inoche.2004.06.004

Inorganic Chemistry Communications 7 (2004) 935–937
www.elsevier.com/locate/inoche
Oxidative addition of Ph3SnH to Pt3(l-CO)3(PR3)3 (R ¼ PCy3, PtBu3)
*
ꢀ
Zoltan Beni, Rosario Scopelliti, Raymond Roulet
ꢀ
Institut des Sciences et Ingꢀenierie Chimiques, Ecole Polytechnique Fꢀedꢀerale de Lausanne, Analytique de I’Universite, BCH-1015 Lausanne, Switzerland
Received 17 May 2004; accepted 2 June 2004
Available online 2 July 2004
Abstract
The oxidative addition of 1 equiv. of Ph3SnH to Pt3(l-CO)3(PCy3)3 affords the triangular cluster [Pt3(l-CO)3(PCy3)3(Ph3Sn)H]
(1). The same reaction with the isostructural 42-electron cluster [Pt3(l-CO)3(PtBu3)3] gives the 18-electron monomeric complex
[PtH(CO)(PtBu3)(SnPh3) ] (2) instead of the 44-electron product. The structure of both complexes in solution have been established
1
by H, 13C, 31P, 195Pt and 119Sn NMR spectroscopic methods and found to be in accordance with the solid state geometry of 1.
Ó 2004 Elsevier B.V. All rights reserved.
Keywords: Platinum clusters; Tin; Hydride; NMR; Crystal structure; Coordination compounds
Some polynuclear platinum-hydride have already
been reported [1–16], most of them based on a Pt3
core stabilized by bridging bidentate phosphine [4–
9,11–13] or phosphido ligands [2,15,16]. To the best of
our knowledge the unique hydride derivative of the
well known [Pt3(l-CO)3(PR3)3] 42-electron clusters is
the unstable cationic [Pt3(l3-H)(l-CO)3(PCy3)3]þ
formed by protonation under carefully chosen condi-
triangular Pt complex containing both H and Sn(IV)
functions [Pt3(l-CO)3(PCy3)3(Ph3Sn)H] (1) formed in
the oxidative addition of Ph3SnH to [Pt3(l-
CO)3(PCy3)3]. Replacing the phosphine ligand in the
starting cluster by PtBu3 results in the formation of
PtH(CO)(PtBu3)(SnPh3) (2) instead of the expected
analogue of 1.
Complex 1 (Fig. 1) crystallizes as a solvate with the
composition [Pt3(SnPh3)(l-CO)3(PCy3)3H] ꢀ 3CH2Cl2.
X-ray analysis 2 shows that 1 is a Pt(II)Pt(0)Pt(0) cluster
complex where one Pt inserted into the Sn–H bond.
The platinum triangle is almost isosceles, with Pt–Pt
1
tions [14]. Here we report the formation of a stable
* Corresponding author. Tel.: +41-21-693-9861; fax: +41-21-693-
9865.
E-mail address: raymond.roulet@epfl.ch (R. Roulet).
ꢁ
distances of 2.65 and 2.70 A. These bond lengths are
similar to the metal–metal distances observed in the
1
[Pt3(SnPh3l-CO)3(PCy3)3H] (1). Ph3SnH (30 mg 0.085 mmol)
was added to a CH2Cl2 solution (25 ml) of [Pt3(l-CO)3(PCy3)3]
(0.127 g, 0.084 mmol), and an immediate colour change from orange-
red to yellow was observed. The mixture was stirred for 10 min at
room temperature and monitored by IR. Addition of MeOH followed
by concentration of the resulting solution gave a yellow solid upon
standing overnight at )20 °C (0.116 g, 74% yield). Selected IR data
(cmꢁ1): CH2Cl2 solution m(CBO) 1819vs; 1776vs; m(Pt–H): 1985(br)
2034(br). Yellow single crystals were obtained from a CH2Cl2 solution
standing at 5 °C. Anal. Calc. for C75H115O3P3SnPt3: C, 48.39; H, 6.22.
Found: C, 48.60; H, 6.43. NMR data d(H) ¼ 0.5, d(P2,3) ¼ 70.4,
d(P1) ¼ 59.2, d(C1,3) ¼ 229.3, d(C2) ¼ 261.1, d(Pt2,3) ¼ )4153.1,
2
Empirical formula: C78H121Cl6O3P3Pt3Sn; Formula weight:
ꢁ
2116.32 g/mol; Temperature: 140(2) K; Wavelength: 0.71073 A;
Crystal system: Monoclinic; Space group: P2(1)/n; Unit cell dimen-
ꢁ
ꢁ
ꢁ
sions: a ¼ 13:9351ð5Þ A, b ¼ 18:0950ð10Þ A, c ¼ 32:6165ð16Þ A,
3
ꢁ
a ¼ 90°, b ¼ 91.614(3)° c ¼ 90°; Volume: 8221.2(7) A ; Z ¼ 4; Density
(calculated): 1.710 g/cm3; Absorption coefficient: 5.687 mmꢁ1; F (0 0 0):
4176; Crystal size: 0.33 ꢂ 0.18 ꢂ 0.14 mm3; h range for data collection:
2.74–25.03°; Index ranges: ꢁ16 6 h 6 16, ꢁ21 6 k 6 21, ꢁ38 6 l 6 38;
Reflections collected: 47,692; Independent reflections: 13,722
[Rint ¼ 0.0770]; Completeness to h ¼ 25.03° 94.5%; Absorption correc-
tion: Empirical (DELABS); Max. and min. transmission: 0.871 and
0.576; Refinement method: Full-matrix least-squares on F 2; Data/
restraints/parameters: 13,722/274/844; Goodness of fit on F 2: 0.908;
Final R indices [I>2sigma(I)]: R1 ¼ 0:0430, wR2 ¼ 0:0800; R indices (all
data): R1 ¼ 0:0973, wR2 ¼ 0:1052; Largest difference peak and hole:
d(Pt1) ¼ )4366.0,
d
(Sn) ¼ 54.1, 1J(Pt1–H1) ¼ 1018, 2J(Sn–H1) ¼
)140, 2J(P1–H1) ¼ 9, 2J(Pt2,3–H1) ¼ )46, 1J(Pt2,3–P2,3) ¼ 4305,
2
2
1J(Pt1–P1)¼2264, J(Pt2,3–P1)¼314, J(Pt1–P2,3)¼425, 2J(Sn–P1)¼
)1222, 3J(P1–Pt2,3) ¼ 52.7, 3J(P2–P3) ¼ 55, 1J(Pt2,3–Pt1) ¼ 1128,
1J(Pt2,3–Pt3,2) ¼ 1871,
1J(Sn–Pt1) ¼ 6330,
2J(Sn–Pt2,3) ¼ 498.5,
1J(Pt2,3–C1,3) ¼ 845, 1J(Pt2,3–C2) ¼ 766, 1J(Pt1–C1,3) ¼ 380.
1.918 and )1.929 e/A .
3
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1387-7003/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.inoche.2004.06.004

936
Z. Bꢀeni et al. / Inorganic Chemistry Communications 7 (2004) 935–937
parent cluster [19], but large differences are observed in
comparison to the corresponding values involving Pt1.
This supports that the Pt1 metal centre is inserted into
the Sn–H bond and that the P1 phosphine group is
tipped out from the plane of the metal core. The ob-
served large 2J(Sn–P1) value of 1222 Hz is in agreement
with this suggestion and suggests a trans arrangement of
these ligands.
1
The H NMR spectrum presents a hydride signal at
0.5 ppm appearing as a shoulder of the about 160 times
more intense multiplet peaks belonging to the methylene
protons of the three phosphine-ligands (therefore the
2J(Sn–H) coupling constant is estimated from gNMR
simulation). We have no explanation for the chemical
shift value of 0.5 ppm which is unusual, but note that
there are other examples where metal-hydrides are un-
usually low fielded [4,10].
The 2J(Sn–H) value of 140 Hz suggests a cis ar-
rangement of the organotin and hydride ligands
[10,20]. Neither the 13C nor the 31P non-decoupled
NMR spectra are indicative of the presence of the
hydride ligand, because the two-bond couplings in-
volving these nuclei are small relative to the natural
line-broadening deriving from couplings with the cy-
clohexyl protons.
Since the proton spectrum is not clearly indicative for
the presence of the hydride ligand, non-decoupled 195Pt
NMR measurements have been achieved. No change is
noted in the signals belonging to Pt2 and Pt3, while du-
plication of the peaks belonging to Pt1 metal centre is
observed (Fig. 2). The deduced 1J(Pt1–H) coupling
constant value of 1018 Hz is significantly larger than the
corresponding coupling constant values of the above
referred complexes [4,10] and suggests that the hydride
Fig. 1. ORTEP representation of complex 1 and of its metal core
(R ¼ 0:0458).
starting cluster [17], and are shorter than the corre-
sponding platinum–platinum distances in its 44-elec-
tron analogue [Pt3(l-CO)3(PCy3)4] [18]. The P2 and P3
atoms (see Fig. 1 for numbering) stay in the plane of
the platinum triangle, while P1 is tipped out from this
plane and occupies an opposite side of the core relative
to the Sn(IV) unit. The Pt2–P2 and Pt3–P3 distances
ꢁ
are almost identical (2.28 and 2.27 A, respectively) as
well as the Pt–C(carbonyl) distances, involving Pt2 or
ꢁ
Pt3 metal centres (ꢃ2.0 A). These bond lengths are
-4320.0 -4340.0 -4360.0 -4380.0 -4400.0 -4420.0
similar to the corresponding bond lengths observed in
ꢁ
the starting [3:3:3] cluster [17]. The Pt1–P1 (2.34 A)
ꢁ
and Pt1–C1,C3 (2.18 and 2.14 A) bond length – as
expected from the increased coordination number of
this metal centre – are significantly longer compared to
the latter ones.
NMR and IR spectroscopic properties suggest similar
stereochemistries of complex 1 in solution and in the
solid state. NMR spectra appear as a superimposition of
subspectra belonging to the isotopomers differing in the
1
isotopic distribution of these nuclei. d and J values
involving Pt2,3 and the ligands bonded to these metal
centres are similar to the corresponding values in the
Fig. 2. Hydride indication from non-decoupled (top) and 1H decou-
pled (bottom) 195Pt spectra of 1 in CD2Cl2.

Z. Bꢀeni et al. / Inorganic Chemistry Communications 7 (2004) 935–937
937
ligand is coplanar with the plane defined by the metal
core.
or from the Cambridge Crystallographic Data Centre,
12, Union Road, Cambridge, CH2 1EZ, UK [Fax: (in-
ternat.) +44-1223/336-033; E-mail: deposit@ccdc.cam.
ac.uk].
No further reaction occurs in the presence of excess
of organotin-hydride. Complex 1 is stable in solution for
several hours at room temperature and can be kept for
at least several weeks at +5 °C. Decomposition occurs
upon standing overnight in solution at room tempera-
ture, giving back the starting cluster and other uniden-
tified decomposition products.
References
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The experiment was repeated with the starting cluster
containing PtBu3 as ligand, which has simpler 1H NMR
features. Ph3SnH reacts easily with this cluster as well,
but surprisingly a monomeric complex [PtH(SnPh3)
[2] P.L. Bellon, A. Cariotti, F. Demartin, G. Longoni, J. Chem. Soc.,
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7785.
3
CO(PtBu3)] (2) is obtained instead of the expected
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spectra did not give any indication of the formation of
the latter complex down to )90 °C.
[5] M.C. Jennings, N.C. Payne, R.J. Puddephatt, J. Chem. Soc.,
Chem. Commun. (1986) 1809.
The 1H NMR spectrum clearly indicates the presence
of a terminal hydride, presenting twelve lines centered at
)1.6 ppm. The central lines are doublet of doublets (2J(P–
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3776.
[7] D. Carmichael, P.B. Hitchcock, J.F. Nixon, A. Pidcock, J. Chem.
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2
H) ¼ )17.8 Hz and J(P–C) ¼ )2.3 Hz), flanked by sa-
[8] G. Douglas, L. Manojlovic, K.W. Muir, M.C. Jennings, B.R.
Lloyd, M. Rashidi, R.J. Puddephatt, J. Chem. Soc., Chem.
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tellite peaks due to couplings with 195Pt (1J(Pt–H) ¼ 775
Hz) and 119Sn (2J(Sn–H) ¼ )36.7). The 1J(Pt–H) value is
in between the corresponding values in trans- and cis-
[PtH(SnPh3)(PCy3)2] (918 and 638 Hz, respectively)
found by Clark et al. [20]. The same comparison for
2J(Sn–H) values (698 and 26 Hz, respectively) rules out a
cis-Sn–H arrangement in 2. The 2J(P–H) value (17.8 Hz)
suggests a cis-arrangement of these two ligand as well,
while 2J(C–H) (54.4 Hz) indicates a possible trans-CO–H
arrangement. The coupling constants deduced from
13C{1H}, 31P{1H}, 195Pt{1H} and 119Sn{1H} NMR
spectra confirm the ligand arrangement suggested by 1H
NMR.
[9] M. Rashidi, R.J. Puddephatt, Organometallics 7 (1988) 1636.
[10] M.C. Jennings, G. Schoettel, S. Roy, R.J. Puddephatt, Organo-
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Puddephatt, Inorg. Chem. 30 (1991) 4048.
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Inorg. Chem. 31 (1992) 4236.
[13] R. Ramachandran, R.J. Puddephatt, Inorg. Chem. 32 (1993) 2256.
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(1994) 1029.
[15] P. Leoni, S. Manetti, M. Pasquali, A. Albinati, Inorg. Chem. 35
(1996) 6045.
[16] A. Fortunelli, P. Leoni, L. Marchetti, M. Pasquali, F. Sbrana, M.
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Supplementary material
[19] A. Moor, P.S. Pregosin, L.M. Venanzi, Inorg. Chim. Acta 48 (1981)
153.
CCD 238905 contains supplementary crystallo-
graphic data for this paper. These can be obtained free
of charge at www.ccdc.cam.ac.uk/conts/retriving.html
[20] H.C. Clark, G. Ferguson, M.J. Hampden-Smith, H. Ruegger,
B.L. Ruh, Can. J. Chem. 66 (1988) 3120.
3
[Pt(SnPh3)CO(PtBu3)3H] (2). [Pt3l-CO)3(PtBu3)3] (69 mg, 0.054
mmol) was added to a CH2Cl2 solution (20 ml) of Ph3SnH (57 mg
0.162 mmol) and an immediate colour change from orange to pale
yellow was observed. The mixture was stirred for 20 min at room
temperature while reaction progress was monitored by IR spectros-
copy. Addition of heptane followed by concentration of the resulting
solution gave pale yellow microcrystals (0.75 g, 59.5%). Selected IR
data (cmꢁ1): CH2Cl2 solution m(CBO) 2001vs; m(Pt–H): 2116(s). Anal.
Calc. for C31H42OPSnPt: C, 47.95; H, 5.58. Found: C, 47.56; H, 5.76.
NMR data (d in ppm, J in Hz): d(H) ¼ )1.6; d(C) ¼ 197.2; d(P) ¼ 98;
d(Sn) ¼ )64.9; d(Pt) ¼ )5152; 1J(Pt–H) ¼ 775; 1J(Pt–P) ¼ 2372; 1J(Pt–
C) ¼ 1207; 1J(Pt–Sn) ¼ 8547; 2J(P–H) ¼ )17.8; 2J(C–H) ¼ )54.4;
2J(Sn–H) ¼ )36.7; 2J(P–C) ¼ )2.3; 2J(P–Sn) ¼ )1230; 2J(C–
Sn) ¼ )52.