Synthesis and structures of cis- and trans-bis(alkyneselenolato) platinum(II) complexes

Article abstract of DOI:10.1021/ic048454a

The reaction of 2 equiv of LiSeCC-n-C₅H₁₁ (1) with cis-PtCl₂(Ph₃P)₂ (2) gives a mixture of the cis and trans isomers of Pt(Ph₃P)₂(SeCC-n-C₅H ₁₁)₂

Full text of DOI:10.1021/ic048454a

Inorg. Chem. 2005, 44, 2798−2802
Synthesis and Structures of cis- and
trans-Bis(alkyneselenolato)platinum(II) Complexes
§
fer,† Carmen Moser,‡ Jurgen J. Tirre´e, Martin Nieger,§ and Rudolf Pietschnig*,‡
1
Sven Scha
1
Fakulta¨t fu¨r Chemie, Ruhr-UniVersita¨t Bochum, UniVersita¨tsstrasse 150,
D-44780 Bochum, Germany, Institut fu¨rAnorganische Chemie, Rheinische
Friedrich-Wilhelms-UniVersita¨t Bonn, Schubertstrasse 1, D-53121 Bonn, Germany, and
Institut fu¨r Chemie, Karl-Franzens-UniVersita¨t Graz, Schubertstrasse 1, A-8010 Graz, Austria
Received November 4, 2004
The reaction of 2 equiv of LiSeCC-n-C5H11 (1) with cis-PtCl2(Ph3P)2 (2) gives a mixture of the cis and trans isomers
of Pt(Ph3P)2(SeCC-n-C5H11)2 (3), which slowly isomerizes in CH2Cl2 to the preferred trans form trans-3. The closely
related cis-[Pt(dppf)2(SeCC-n-C5H11)2] (4) (dppf
) bis(diphenylphosphino)ferrocene) was prepared by a similar
metathetical reaction using the platinum chloride complex of the chelating dppf to impose the cis geometry. The
structures of the cis and trans complexes have been investigated in solution by heteronuclear NMR (31P, 77Se, and
195Pt) and, in the cases of trans-3 and 4, characterized in the solid state by single-crystal X-ray diffraction. Changing
the coordination geometry from cis to trans induces significant changes in the structural and spectroscopic parameters,
which do not comply with the previously anticipated donor−acceptor properties of selenolate ligands.
Introduction
structural flexibility, their unique electronic situation, and
the antioxidative activity of biomimetic models based on
structurally related organoselenium compounds.5,6
Alkynechalcogenolates (A) can be described as chalcogeno
ketene anions (B) and are capable of showing unique
ambident rectivity.1 This ambident behavior has been mainly
explored toward organic or main group based electrophiles
in the case of alkynelthiolates, mostly aiming at thioketenes.
In contrast, much less information is available about the
reactivity and coordination chemistry of alkynelthiolates
toward transition metals, which started to develop only
recently.2 Even less information is available for their
selenium analogues, i.e., the alkyneselenolates, despite the
favorable NMR properties of the 77Se nucleus. The first
examples exploring the coordination behavior of these
unusual ligands have been described by Tatsumi and co-
workers.3,4 The growing interest in the chemistry and
coordination behavior of alkyneselenolates stems from their
In this contribution we describe our results dealing with
the coordination behavior of alkyneselenolates toward plati-
num. Using an alkyl-substituted alkyneselenolate, we syn-
thesized cis and trans platinum complexes of this ligand
which were characterized by heteronuclear NMR spectros-
copy and X-ray diffraction. While the coordination chemistry
of alkyneselenolates itself is rather unexplored, these com-
pounds represent the first (alkyneselenolato)platinum com-
plexes. The structural and spectroscopic comparison of
closely related cis- and trans-bis(alkyneselenolato) complexes
shows that the electronic situation differs from that of other
selenolate ligands.
* Author to whom correspondence should be addressed. E-mail:
rudolf.pietschnig@uni-graz.at. Fax: +43 316 380 9835. Tel: +43 316 380
5285.
Results and Discussion
† Ruhr-Universita¨t Bochum.
‡ Karl-Franzens-Universita¨t Graz.
Generally two routes are available for the coordination of
alkyneselenolates. The first approach proceeds via salt
§ Rheinische Friedrich-Wilhelms-Universita¨t Bonn.
(1) Raubenheimer, H. G.; Kruger, G. J.; Linford, L.; Marais, C. F.; Otte,
R.; Hattingh, J. T. Z.; Lombard, A. J. Chem. Soc., Dalton Trans. 1989,
1565-1577.
(4) Sunada, Y.; Hayashi, Y.; Kawaguchi, H.; Tatsumi, K. Inorg. Chem.
2001, 40, 7072-7078.
(5) Ma, N. L.; Wong, M. W. Eur. J. Org. Chem. 2000, 1411-1421.
(6) Mugesh, G.; Panda, A.; Singh, H. B.; Punekar, N. S.; Butcher, R. J.
J. Chem. Soc., Chem. Commun. 1998, 2227-2228.
(2) Weigand, W.; Weisha¨upl, M.; Robl, C. Z. Naturforsch., B 1996, 501-
505.
(3) Sugiyama, H.; Hayashi, Y.; Kawaguchi, H.; Tatsumi, K. Inorg. Chem.
1998, 37, 6773-6779.
2798 Inorganic Chemistry, Vol. 44, No. 8, 2005
10.1021/ic048454a CCC: $30.25
© 2005 American Chemical Society
Published on Web 03/24/2005

Bis(alkyneselenolato)platinum(II) Complexes
Scheme 1. Synthetic Routes to Alkyneselenolate Complexes
Table 1. Comparison of Selected Bond Lengths (Å) and Angles (deg)
in trans-3 and 4
trans-3
4
Pt1-P1
2.348(2)
2.4902(9)
1.811(4)
1.177(5)
1.446(6)
Pt1-P1
2.2819(13)
2.2882(12)
2.4639(5)
2.4608(6)
1.831(5)
1.817(6)
1.199(7)
1.205(8)
1.477(9)
Pt1-P2
metathesis from the corresponding metal halide and an alkali
alkyneselenolate (metathesis route) (Scheme 1, top).3,4 The
second approach takes advantage of an insertion of selenium
into an alkyne-metal bond (insertion route), where the metal
is cadmium and mercury (Scheme 1, bottom).7,8
Pt1-Se1
Se1-C19
C19-C20
C20-C21
Pt1-Se1
Pt1-Se2
Se1-C35
Se2-C42
C35-C36
C42-C43
C36-C37
C43-C44
Recently we reported some alkyneselenolates carrying
substituents with different electronic and steric properties.9,10
To minimize electronic interaction of the substituent with
the adjacent CCSe unit, we have chosen an alkyl derivative,
i.e., heptyneselenolate, as designated ligand for complexation.
Therefore, we explored both of the above-mentioned syn-
thetic routes to obtain complexes of the formula (PenCCSe)2Pt-
(PR3)2 (Pen ) pentyl). The insertion route starting from
(PenCC)2Pt(PR3)2 failed in our hands, and under various
conditions frequently resulted in the formation of the
corresponding selenophosphorane SePR3 as the main product
(Scheme 2). The identity of the latter is established on the
basis of the 31P and 77Se NMR spectra of the reaction mixture
as well as mass spectrometry. One might assume that the
relatively high Pt-C bond strength could be the reason for
the failure of this route.11 However, unlike the only about
half as weak Cd-C bond,12 the Hg-C bond is of similar
strength and undergoes this reaction.13
1.489(10)
P1-Pt1-P1a
180.00(4)
180.00(2)
83.37(3)
83.37(3)
96.63(3)
96.63(3)
100.6(1)
P1-Pt1-P2
97.98(4)
85.07(2)
170.34(3)
176.55(3)
91.53(3)
85.44(3)
110.0(2)
112.8(2)
170.3(6)
175.5(7)
178.1(10)
175.6(10)
178.8(3)
Se2a-Pt1-Se2
P1-Pt1-Se2a
P1#1-Pt1-Se2
P1a1-Pt1-Se2a
P1-Pt1-Se2
Se1-Pt1-Se2
P1-Pt1-Se2
P2-Pt1-Se1
P2-Pt1-Se2
P1-Pt1-Se1
C35-Se1-Pt1
C42-Se2-Pt1
C36-C35-Se1
C43-C42-Se2
C35-C36-C37
C42-C43-C44
C19-Se2-Pt1
C20-C19-Se2
C19-C20-C21
176.9(4)
177.5(5)
Cp(1)-Fe-Cp(2)
Table 2. Crystal and Structure Refinement Data for trans-3 and 4
trans-3
4
formula
fw
C50H52P2PtSe2‚2CH2Cl2
C
48H50FeP2PtSe2‚C6H6
1237.72
213
0.710 73
triclinic
P1h (No. 2)
1175.79
123
temp, K
wavelength, Å
cryst system
space group
unit cell dimens
a, Å
0.710 73
monoclinic
P21/c (No. 14)
In contrast, the metathesis route turned out to be successful
for our purpose. Thus, the reaction of lithium heptynesele-
nolate (1) with cis-dichlorobis(triphenylphosphine)platinum-
(II) (cis-(Ph3P)2PtCl2) (2) at -78 °C furnishes the desired
bis(alkyneselenato)platinum complex 3 as an orange solid
(λmax ) 212 nm). As in related cases,14 starting from cis-2
results in the formation of a mixture of cis-3 and trans-3,
whereof trans-3 is the dominant form (ratio 4:1) (Scheme
3). In the 31P NMR spectra trans-3 shows a resonance at
11.188(2)
11.425(2)
11.828(2)
99.34(3)
99.05(3)
119.17(3)
1252.7(4)
1
11.4545(1)
22.1938(2)
19.1997(2)
90
104.241(1)
90
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
4730.93(8)
4
Z
d(calcd), Mg/m3
µ, mm-1
1.641
4.565
1.651
4.903
θ range for data collcn, deg 2.09-25.66
2.96-27.48
goodness-of-fit on F2
R1 (obsd data)
1.013
0.0257
0.0599
1.040
0.0365
0.1047
1
28.0 ppm with a JPPt coupling constant of 2858 Hz and a
2JPSe coupling constant of 26 Hz. The cis isomer of 3 has a
wR2 (all data)
chemical shift of 23.6 ppm with larger coupling constants
1
than found for trans-3 (i.e., cis-3: JPPt ) 3220 Hz and 2JPSe
Table 3. Relevant NMR Spectroscopic Data for cis-/trans-3 and 4
) 42 Hz). Relevant NMR spectroscopic data for cis- and
trans-3 are summarized in Table 3.
Recrystallization from dry methylene chloride affords pure
crystalline trans-3 for which we were able to obtain a crystal
structure. The asymmetric unit of trans-3 contains a planar
coordinated Pt(II) center, which is also an inversion center,
trans-3
cis-3
cis-4
δ(31P), ppm
δ(77Se), ppm
δ(195Pt), ppm
1JPPt, Hz
28.0
23.6
19.4
330
-5009
3287
240
-4985
2858
198
3220
42
1JPtSe, Hz
2JPSe, Hz
26
and two molecules of methylene chloride. As already derived
from the NMR spectra the alkyneselenolato ligands adopt a
trans configuration in the approximately square planar
coordination environment around platinum (Figure 1). The
phosphane and the alkyneselenolate units in trans-3 show
Pt(1)-P(1) (2.348(2) Å) and Pt(1)-Se(2) (2.4902(9) Å)
distances which are slightly longer than the values reported
for the related trans-[Pt(PPh3)2(SePh)2] and even more so
compared to cis-[Pt(PPh3)2(SePh)2].14
(7) Beswick, M. A.; Raithby, P. R.; Steiner, A.; Vallat, J. C.; Verhorevoort,
K. L.; Wright, D. S. J. Chem. Soc., Dalton Trans. 1996, 2183-2184.
(8) Cook, D. J.; Hill, A. F.; Wilson, D. J. J. Chem. Soc., Dalton Trans.
1998, 1171-1173.
(9) Pietschnig, R.; Merz, K.; Scha¨fer, S. Heteroatom Chem. 2005, 16,
169-174.
(10) Pietschnig, R.; Scha¨fer, S.; Merz, K. Org. Lett. 2003, 5, 1867-1869.
(11) Kapadia, R.; Pedley, J. B.; Young, G. B. Inorg. Chim. Acta 1997,
265, 235-239.
(12) Carson, A. S.; Hartley, K.; Skinner, H. A. Nature 1948, 161, 725-
726.
(13) Schwerdtfeger, P. J. Am. Chem. Soc. 1990, 112, 2818-2820.
(14) Hannu, M. S.; Oilunkaniemi, R.; Laitinen, R. S.; Ahlge´n, M. Inorg.
Chem. Commun. 2000, 3, 397-399.
This is surprising, because in related work dealing with
(areneselenolato)platinum complexes longer Pt-P bonds in
Inorganic Chemistry, Vol. 44, No. 8, 2005 2799

Scha1fer et al.
Scheme 2. Attempted Synthesis of 3 via the Insertion Route (R ) Pentyl; Ph ) Phenyl)
Scheme 3. Synthesis of 3 (R ) Pentyl)
Scheme 4. Synthesis of 4 (R ) Pentyl)
trans relative to cis complexes have been interpreted as a
result of slightly stronger trans influence of -SeR compared
to that of PPh3.14 On the other hand, this concept should be
concomitant with a decrease of the Se-Pt bond length in
the trans form compared to the cis form, which has not been
observed and is also not supported by our findings.
the electronic reasons quoted for metal thiolates.15 Relevant
geometric parameters and details of the experimental data
collection for trans-3 are listed in Tables 1 and 2, respec-
tively.
We were interested to compare the structural results
obtained for trans-3 with its cis isomer. As in the case of
the related (benzeneselenolate)platinum complexes, slow
isomerization of cis-3 to trans-3 in solution precluded the
growth of crystals of cis-3 suitable for X-ray diffraction,
however. To circumvent this issue, we replaced the triphen-
ylphosphine ligands with a chelating diphosphine to enforce
cis geometry. We have chosen bis(diphenylphosphino)-
ferrocene (dppf) rather than bis(diphenylphosphino)ethylene
(dppe), which has been used in previous investigations,2
because from its electronic and steric properties the ferro-
cenylene unit is closer to a phenyl group than alkylidene
units.16 To synthesize an analogous complex with cis
geometry, we started from (dppf)PtCl2, which we reacted
with lithium heptyneselenolate (1) to give the cis-bis-
(alkyneselenato)platinum complex 4 (Scheme 4).
We determined the structure of 4 in the solid state by X-ray
diffraction which confirms the cis arrangement of the
alkyneselenolate ligands (Figure 2). The Pt-P distances
(2.2819(13)-2.2882(12) Å) and the Pt-Se bond lengths
(2.4608(6)-2.4639(5) Å) in 4 are both shorter than the
respective ones in trans-3. In contrast, the bond lengths
associated with the alkyneselenolate unit appear slightly
elongated in the cis complex compared to the trans complex
as for instance the CtC triple bonds in 4 are 1.199(7)-
1.205(8) Å relative to 1.177(5) Å in trans-3. As is evident
from the CtC-C angles (175.6(10)-178.1(10)°) the alkynyl
groups show an arrangement close to linearity. Somewhat
larger are the deviations from ideal linearity for the corre-
sponding Se-CtC angles, which range from 170.3(6) to
175.5(7)°. Within the approximately square planar coordina-
tion environment around platinum, the neighboring atoms
show angles in the range between 85.07(2) and 97.98(4)°,
Figure 1. Molecular structure of trans-3 with thermal ellipsoids (50%
probability level). Solvent molecules were omitted for clarity.
Within the CtC-Se unit, the C(19)-C(20) bond length
of 1.177(5) Å is characteristic for a CtC triple bond, while
the Se(2)-C(19) distance is with 1.811(4) Å at the shorter
end of the range (1.828(7)-1.851(7) Å) observed for a Se-C
bond in alkyneselenolates so far.3,4,7 The angle between Se-
(2)-C(19)-C(20) is almost linear (176.9(4)°), which indi-
cates that the contribution of the selenoketenyl resonance
structure is negligible. The square planar geometry around
platinum is slightly distorted. While the sum of the bond
angles necessarily is 360° due to the inversion center, the
P(1)-Pt(1)-Se(2) and the P(1a)-Pt(1)-Se(2) angles differ
by more than 10° (83.37(3)° vs 96.63(3)°). We attribute this
feature to the steric repulsion between the heptynyl unit with
preferably one of the triphenylphosphine groups as well as
(15) Ashby, M. T. Comments Inorg. Chem. 1990, 10, 297-313.
(16) Pietschnig, R. Ferrocenylphosphane und -phosphorane; Tectum Ver-
lag: Marburg, Germany, 1997.
2800 Inorganic Chemistry, Vol. 44, No. 8, 2005

Bis(alkyneselenolato)platinum(II) Complexes
In summary, we synthesized closely related cis and trans
platinum complexes of SeCC-n-C5H11 and elucidated their
structures in solution and the crystalline state. In line with
previous work, we find exclusive coordination of the
selenium atom of the ambident alkyneselenolate ligand and
a preference for the obviously more stable trans isomer. In
contrast to previous work, we find a uniform increase of all
metal-ligand bond lengths in the cis vs the trans isomers.
This is an indication that the structural changes are more
likely a consequence of steric repulsion than a stronger trans
influence of alkyneselenolate ligands.
Experimental Section
1H, 13C, 31P, 77Se, and 195Pt NMR spectra have been recorded
on Bruker AMX 360 and Bruker DPX 250 instruments at room
temperature. Chemical shift values are given in ppm and are
referenced to external standards. Mass spectra have been measured
on Kratos Concept 1-H and VG Autospec spectrometers using the
FAB ionization technique with m-NBA matrix. Microanalysis were
measured on a VarioEL v2.3. Compounds 1, 2, and (dppf)PtCl2
have been prepared according to published procedures.9,18,19 All
experiments have been carried out under an argon atmosphere using
standard Schlenk techniques. The resulting products are moderately
air sensitive.
Figure 2. Molecular structure of one orientation of 4 with thermal
ellipsoids (50% probability level), except for the disordered pentyl groups.
For clarity, the solvent molecule and one site of the disordered pentyl groups
have been omitted.
where the largest value corresponds to the P1-Pt1-P1 angle
involving the bis(phosphine) ligand. To adjust the bite angle
of the dppf ligand, the Cp rings of the ferrocenyl unit are
twisted by 34.5° (P(1)-Cp(1)-Cp(2)-P(2)). The Cp-Fe-
Cp system is almost linear with an angle of 178.8(3)°. The
Pt-Fe distance of 4.299 Å significantly exceeds the sum of
the van der Waals radii; therefore, any direct interaction
between these atoms appears unlikely. Relevant geometric
parameters and details of the experimental data collection
for 4 in comparison to trans-3 are summarized in Tables 1
and 2, respectively.
Synthesis of Bis(1-heptyneselenolato)(triphenylphosphine)-
platinum(II) (3). A solution of lithium heptyneselenolate (0.36 g,
2 mmol) in ether (40 mL) was cooled to -78 °C. To this mixture
solid cis-PtCl2(PPh3)2 (0.79 g, 1 mmol) was added while stirring.
The mixture was slowly warmed to room temperature, and stirring
was continued for 12 h upon which white and yellow precipitates
were observed. These were filtered under argon, and the supernatant
liquid was discarded. The residue was extracted with methylene
chloride, and the filtrate was separated. The solvent of the filtrate
was evaporated in a vacuum, and the product was obtained as an
oily residue which slowly crystallized (0.85 g, 80%). Prolonged
evacuation of the crystalline material gave analytically pure samples.
Anal. Calcd for C50H52P2PtSe2‚CH2Cl2 (Mr ) 1152.83): C, 53.13;
H, 4.72. Found: C, 53.50; H, 5.04.
In addition to the structural changes that can be observed
for cis-3 and 4, the heteronuclear NMR spectra reveal
valuable information related to the bonding situation in
(alkyneselenolato)platinum complexes. Relevant NMR spec-
troscopic data for cis-/trans-3 and 4 are summarized in Table
3. It can be noted that the 31P resonance of the phosphane
unit in the trans form appears at lower field than in the cis
form. In contrast the 195Pt resonances show the opposite trend
with the 195Pt nucleus in the cis form being more shielded
than in the trans form. Significant changes are observed for
trans-3: 31P NMR (CD2Cl2) δ ) 28.0 (s, 1JPPt ) 2858 Hz, 2JPSe
1
) 26 Hz); 195Pt NMR (CD2Cl2) δ ) -4985 (t, JPtP ) 2858 Hz,
1JPtSe ) 198 Hz); 1H NMR (CD2Cl2) δ 7.7-7.1 (m, 30H), 1.8-0.9
(m, 22H); 13C NMR (CD2Cl2) δ 133.0, 132.1, 130.9, 129 (m,
2
3
phenyl), 93.0 (s, JCPt ) 28 Hz, -Se-C≡C), 64.1 (t, JCP ) 6.7
Hz, -Se-CtC), 31.6, 29.1, 22.8, 20.9, 14.4 (s, pentyl); MS (FAB)
m/z 893 (10%, (M+ - (Se-CtC-Pen)), 718 (65%, (M+ - 2(Se-
CtC-Pen)), 455 (45%, PtSeC13H25+), 357 (100%, Ph3PC7H11+),
263 (50%, HPPh3+); UV/vis 212.4 nm.
1
1
the coupling constants JPPt and JPtSe, which reflect the
metal-ligand interactions. Thus, in the order from trans to
cis, these coupling constants increase by 15% (1JPPt) and 21%
(1JPtSe), indicating an increased bond order.17 This correlates
clearly with the structural findings for compounds trans-3
and 4 for which both the Pt-P and the Pt-Se distances
decrease from trans to cis.
cis-3: 31P NMR (CD2Cl2) δ ) 23.6 (s, 1JP-Pt ) 3220 Hz, 2JP-Se
) 42 Hz).
Synthesis of Bis(1-heptyneselenolato)(1,1′-bis(diphenylphos-
phino)ferrococene)platinum(II) (4). (dppf)PtCl2 (1.07 g, 1.3
mmol) was dissolved in THF (20 mL) and cooled to -78 °C. To
this mixture a solution of lithium heptyneselenolate (0.41 g, 2.24
mmol) in THF (10 mL) was added slowly while stirring. The
mixture was slowly warmed to room temperature, and stirring was
continued for 60 h upon which the mixture turned red. The solvent
was evaporated in a vacuum, and the residual solid was extracted
with benzene. The product solution was separated from the
The fact that both the phosphine and the alkyneselenolate
ligands experience a contraction of the metal-ligand bonds
suggests that the supposedly stronger trans influence of the
selenolate ligand might be only one among other factors.
An alternative explanation might be that the steric situation
in the trans form prevents shorter metal-ligand bond lengths,
while in the cis form steric repulsion is reduced and
consequently shorter metal-ligand distances are feasible.
(18) Nagel, U. Chem. Ber. 1982, 115, 1998.
(17) Nixon, J. F.; Pidcock, A. Annu. ReV. NMR Spectrosc. 1969, 2, 345-
(19) Noh, D. Y.; Seo, E. M.; Lee, H. J.; Jang, H. Y.; Choi, M. G.; Kim, Y.
H.; Hong, J. Polyhedron 2001, 20, 1939-1945.
422.
Inorganic Chemistry, Vol. 44, No. 8, 2005 2801

Scha1fer et al.
eliminated LiCl by filtration through a filter funnel under an argon
atmosphere and subsequently concentrated in a vacuum to incipient
crystallization. From this solution 4 crystallized as an orange yellow
solid at room temperature (0.9 g, 63%). Prolonged evacuation of
the crystalline material gave analytically pure samples: mp 298.5
(dec); 31P NMR (C6D6) δ ) 19.4 (s, 1JPPt ) 3287 Hz); 195Pt NMR
anisotropic displacement parameters without any constraints. For
277 parameters final R indices of R ) 0.0257 and wR2 ) 0.0599
(GOF ) 1.013) were obtained.
Crystal Data for 4. An orange crystal of 4 with dimensions 0.4
× 0.3 × 0.3 mm was coated in paraffin oil, mounted on a glass
fiber, and placed under a cold stream of nitrogen. The measurements
were performed on a Nonius Kappa CCD diffractometer using
graphite-monochromatized Mo KR radiation at 123 K. A total of
71 779 reflections were collected (θmax ) 27.48°), from which
10 644 were unique (Rint ) 0.0571), with 8467 having I > 2σ(I).
Additional experimental details are given in Table 2. The structure
was solved by direct methods (SHELXS-97) and refined by full-
matrix least-squares techniques against F2 (SHELXL-97).20,21 The
atoms C45, C46, C47, and C48 of the pentyl group are disordered
over two sites with an occupancy factor of 0.5. All other
non-hydrogen atoms were refined with anisotropic displacement
parameters without any constraints. For 516 parameters final R
indices of R ) 0.0365 and wR2 ) 0.1047 (GOF ) 1.040) were
obtained. An empirical absorption correction was applied.
1
1
(C6D6) δ ) -5009 (tt, JPtP ) 3287 Hz, JPtSe ) 240 Hz); 77Se
1
NMR (C6D6) δ ) 330; H NMR (C6D6) δ 7.83-7.25 (m, 20H),
4.21 (s, 4H), 3.92 (s, 4H), 1.80-0.75 (m, 22H); 13C NMR (C6D6)
δ 135.3, 131.4, 130.7, 127.2 (phenyl), 100.4 (s, -Se-CtC), 75.7,
73.8, 73.1 (m, Fc′), 60.6 (s, -Se-CtC), 31.2, 28.7, 22.2, 20.8, 13.9
(s, pentyl); MS (FAB) m/z 1099 (M+, 60%), 1003 (M+ - heptyne,
22%), 923 (M+ - heptyneselenol, 100%), 828 (M+ -heptynese-
lenol - heptyne, 60%), 748 (M+ - 2 heptyneselenol, 50%); UV/
vis 263.0 nm. Anal. Calcd for C48H50FeP2PtSe2 (Mr ) 1097.70):
C, 52.52; H, 4.59. Found: C, 52.08; H, 4.65.
Crystal Data for trans-3. An orange crystal of trans-3 with
dimensions 0.3 × 0.2 × 0.2 mm was coated in paraffin oil, mounted
on a glass fiber, and placed under a cold stream of nitrogen. The
measurements were performed on a Bruker AXS CCD 1000
diffractometer using graphite-monochromatized Mo KR radiation
at 213 K. A total of 6971 reflections were collected (θmax ) 25.66°),
from which 4286 were unique (Rint ) 0.0224), with 3867 having
I > 2σ(I). Additional experimental details are given in Table 2.
The structure has been solved by Patterson analysis and subsequent
refinement by full-matrix least-squares techniques against F2
(SHELXL-97).20,21 The non-hydrogen atoms were refined with
Acknowledgment. We acknowledge the FWF (Austrian
Science Fund) for financial support Project P17882-N11.
Supporting Information Available: Details of the X-ray
crystallographic studies for trans-3 and 4 in CIF format and
complete ORTEP plots. This material is available free of charge
via the Internet at http://pubs.acs.org.
IC048454A
(20) Sheldrick, G. M. SHELXL-97. Program for the Refinement of Crystal
Structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(21) Sheldrick, G. M. SHELXS-97. Program for the Solution of Crystal
Structures; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
2802 Inorganic Chemistry, Vol. 44, No. 8, 2005