Structure and solution behaviour of cyclooctadiene complexes of platinum(II)

Article abstract of DOI:10.1016/j.ica.2010.06.020

The substitution behaviour of [PtCl(R)(COD)] (R^- = Me and Fc) complexes, by the stepwise addition of phosphine ligands, L (L = PPh ₃, PEt₃ and P(NMe₂)₃), were investigated in situ by ¹H and

Full text of DOI:10.1016/j.ica.2010.06.020

Inorganica Chimica Acta 363 (2010) 3316–3320
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Structure and solution behaviour of cyclooctadiene complexes of platinum(II)
,1
*
Stefanus Otto
Department of Chemistry, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa
a r t i c l e i n f o
a b s t r a c t
The substitution behaviour of [PtCl(R)(COD)] (Rꢀ = Me and Fc) complexes, by the stepwise addition of
phosphine ligands, L (L = PPh3, PEt3 and P(NMe2)3), were investigated in situ by 1H and 31P NMR spectros-
copy. Addition of less than two equivalents of the phosphine ligand results in the formation of dimeric
Article history:
Received 9 February 2010
Accepted 9 June 2010
Available online 17 June 2010
molecules with the general formula trans-[Pt(R)(l-Cl)(L)]2 for the sterically demanding systems where
Rꢀ = Me/L = P(NMe2)3 and Rꢀ = Fc/L = PEt3, PPh3 and P(NMe2)3 while larger quantities resulted in
cis- and trans mixtures of mononuclear complexes being formed. In the case of the relatively small steric
demanding, strongly coordinating, PEt3 ligand the trans-[PtCl(R)(PEt3)2] mononuclear complexes were
exclusively observed in both cases. The crystal structures of the two substrates, [PtCl(R)(COD)] (Rꢀ = Me
or Fc), as well as the cis-[PtCl(Fc)(PPh3)2] substitution product are reported.
Keywords:
Platinum(II)
Cyclooctadiene
Substitution
Crystallography
Ó 2010 Elsevier B.V. All rights reserved.
1. Introduction
2. Experimental
Metal complexes containing bidentate alkenes have found wide
application as precursors for further functionalisation, especially
cis, cis-1,5-cyclooctadine (COD) and bicyclo[2.2.1]hepta-2,5-diene
(norbornadiene) are commonly used. It is well known [1] that li-
gand substitution processes trans to olefins are extremely rapid
2.1. Chemicals
K2PtCl4 (Next Chimica), cis, cis-1,5-cyclooctadiane (Merck), NaI
(Merck), ferrocene (Aldrich), MeLi (Aldrich), BuLi (1.6 M in hexane),
PPh3 (Aldrich), PEt3 (Merck) and P(NMe2)3 (Merck) were used as
received. Solvents were dried and purified according to standard
procedures and all moisture sensitive operations were performed
using standard anaerobic techniques.
due to the high
p trans effect of these ligands. In addition the ole-
finic ligands could also be readily substituted themselves based on
the nucleophile used during the reaction. In platinum, and the clo-
sely related palladium chemistry, [MX2(COD)] (M = Pt or Pd;
X = halogen) is often prepared from an inorganic metal salt to ren-
der the metal soluble in a variety of organic solvents for further
functionalisation [2]. The halide ligands can be substituted by the
higher halides, or an anionic organic moiety, such as Me or Ph
through the use of standard organolithium- or Grignard chemistry
while the COD may be substituted by a variety of neutral ligands,
such as phosphines.
The formation of dinuclear molecules when treating
[PdCl(Me)(COD)] with one equivalent of a monodentate phosphine
ligand was reported previously [3] while similar behaviour is also
known for the corresponding Pt(II) systems [4]. In this study, see
Scheme 1, the concept is extend to the stepwise substitution of
COD from Pt complexes, [PtCl(R)(COD)] (Rꢀ = Me or Fc), using three
different phosphine ligands, PPh3, PEt3 and P(NMe2)3.
2.2. NMR measurements
1H, 31P and 195Pt NMR spectra were recorded at 295 K in CDCl3
on a Varian Unity 300 spectrometer working at 299.78, 121.35 and
64.27 MHz, respectively. The chemical shifts are reported in ppm,
the 1H spectra were calibrated on the residual CHCl3 peak
(d = 7.25 ppm) as internal standard. The 195Pt spectra were re-
corded with a WALTZ-16 proton decoupling sequence and the peak
resonances are reported in ppm relative to K2PtCl6 (1 g H2PtCl6 in
3 ml 1 M HCl containing 50% D2O, d = 0 ppm) as external reference.
2.3. Synthesis of complexes
[PtCl2(COD)], [PtI2(COD)] and [PtCl(Me)(COD)] were prepared
according to the procedures of Clark and Manzer [5] while Me3SnFc
and [PtCl(Fc)(COD)] was prepared according to the procedure of
Dawoodi et al. [6]. Even though all NMR analysis was identical to
that reported in the original work selected data of the two sub-
strate complexes are again reported for later discussion.
* Tel.: +27 16 960 4456; fax: +27 11 522 3218.
E-mail address: Fanie.Otto@Sasol.com
Currently employed at: Sasol Technology Research and Development, 1 Klasie
1
Havenga Road, Sasolburg 1947, South Africa.
0020-1693/$ - see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2010.06.020

S. Otto / Inorganica Chimica Acta 363 (2010) 3316–3320
3317
2.4.5. cis-[PtCl(Me){P(NMe2)3}2], 7
2
3
1H NMR: 0.64 (dtd, 3H, 1 ꢁ CH3, JPt–H = 54 Hz, JP–H = 3 Hz),
3
1
2.81 (t, 36H, 12 ꢁ CH3, JP–H = 5 Hz). 31P: 78.52 (td, JPt–P
=
2
1
6158 Hz, trans Cl, JP–P = 24 Hz), 118.82 (td, JPt–P = 2654 Hz, trans
2
Me, JP–P = 24 Hz).
2.4.6. trans-[PtCl(Me){P(NMe2)3}2], 8
2
3
1H NMR: 0.43 (tt, 3H, 1 ꢁ CH3, JPt–H = 84 Hz, JP–H = 6 Hz), 2.81
3
1
(t, 36H, 12 ꢁ CH3, JP–H = 5 Hz). 31P: 108.63 (t, JPt–P = 3902 Hz).
2.4.7. [Pt(Fc)(l-Cl)(PPh3)]2, 9
31P: 15.26 (t, JPt–P = 3614 Hz).
1
Scheme 1. Substitution behaviour of COD from [PtCl(R)(COD)] (R = Me or Fc) by
phosphine ligands PR03 (R0 = Ph, Et or NMe2).
2.4.8. cis-[PtCl(Fc)(PPh3)2], 10
1H NMR: 4.10 (t, 2H, 2 ꢁ CH), 4.24 (s, 5H, 5 ꢁ CH), 4.48 (t, 2H,
2
2 ꢁ CH), 7.06–7.62 (m, 30H, 30 ꢁ CH). 31P: 21.06 (d, JP–P = 16 Hz,
2.3.1. [PtCl(Me)(COD)], 1
2
1H NMR: 0.80 (t, 3H, Me, JPt–H = 72 Hz), 2.25–2.60 (m, 8H,
31
195
1JPt–P = 4491 Hz), 24.52 (d,
J
= 16 Hz,
J
= 1698 Hz). 195Pt
P–P
Pt–P
1.5
4 ꢁ CH2), 4.55 (tm, 2H, CH@CH trans to Cl,
J
= 77 Hz), 5.43
NMR: ꢀ2663. Anal. Calc. for C46H39ClFeP2Pt (940.125): C, 58.77;
Pt–H
1.5
(tm, 2H, CH@CH trans to Me,
J
= 36 Hz). Anal. Calc. for
H, 4.18. Found: C, 58.36; H, 4.29%.
Pt–H
C9H15ClPt (353.75): C, 30.56; H, 4.27. Found: C, 30.39; H, 4.15%.
2.4.9. trans-[PtCl(Fc)(PPh3)2], 11
1
31P: 30.42 (t, JPt–P = 3343 Hz).
2.3.2. [PtCl(Fc)(COD)], 2
1H NMR: 2.2–2.7 (m, 8H, 4 ꢁ CH2), 4.16 (s, 2H, 2 ꢁ CH), 4.21 (s,
3
5H, 5 ꢁ CH), 4.36 (t, 2H, 2 ꢁ CH, JPt–H = 17 Hz), 5.16 (tm, 2H,
2.4.10. [Pt(Fc)(l-Cl)(PEt3)]2, 12
1.5
CH@CH trans to Cl,
J
= 76 Hz), 5.64 (tm, 2H, CH@CH trans to
Pt–H
1
14.31 (t, JPt–P = 4692 Hz).
1.5
Fc,
J
= 34 Hz). Anal. Calc. for C18H21ClFePt (523.74): C, 41.28;
Pt–H
H, 4.04. Found: C, 40.99; H, 3.98%.
2.4.11. trans-[PtCl(Fc)(PEt3)2], 13
31P: 17.29 (t, JPt–P = 2761 Hz).
1
2.4. Solution studies
2.4.12. [Pt(Fc)(l-Cl){P(NMe2)3}]2, 14
In a typical experiment a CDCl3 solution containing 35 mM of
the Pt COD precursor was prepared in an NMR tube and an aliquot
of the desired phosphine was added using a micro syringe to obtain
final concentrations ranging from 0.8 to 2.2 mol equivalents. The
solutions were shaken well and aged overnight at room tempera-
ture to ensure that the reaction had been completed before 1H
and 31P NMR spectra were collected. In the reactions with
[PtCl(Fc)(COD)] the 1H spectra were not well resolved and hence
only the 31P results are reported. In the case of cis-[PtCl(Fc)(PPh3)2],
for which crystals were isolated, the complex was characterised
using multiple techniques.
1
31P: 78.91 (t, JPt–P = 5411 Hz).
2.4.13. cis-[PtCl(Fc){P(NMe2)3}2], 15
1
2
31P: 75.50 (td, JPt–P = 5907 Hz, trans Cl, JP–P = 26 Hz), 112.66
1
2
(td, JPt–P = 1716 Hz, trans Me, JP–P = 26 Hz).
2.4.14. trans-[PtCl(Fc){P(NMe2)3}2], 16
1
31P: 101.34 (t, JPt–P = 3854 Hz).
2.5. Crystallography
2.4.1. cis-[PtCl(Me)(PPh3)2], 3
2
3
1H NMR: 0.71 (dtd, 3H, 1 ꢁ CH3, JPt–H = 57 Hz, JP–H = 5 Hz,
Crystals of [PtCl(Me)(COD)], 1, were obtained from MeOH and
those of [PtCl(Fc)(COD)], 2 and cis-[PtCl(Fc)(PPh3)2], 10, from chlo-
roform. The intensity data collections were done on a Siemens
3JP–H = 5 Hz), 7.1–7.2 (m, 12H, 12 ꢁ CH), 7.2–7.3 (m, 6H, 6 ꢁ CH),
7.4–7.5 (m, 12H, 12 ꢁ CH). 31P: 22.21 (td, JPt–P = 4506 Hz, trans
1
Cl, 2JP–P = 13 Hz), 26.99 (td, 1JPt–P = 1726 Hz, trans Me, 2JP–P = 13 Hz).
SMART CCD diffractometer using Mo K
a (0.71073 Å) and x-scans
at 293(2) K. All reflections were merged and integrated using SAINT
[7] and were corrected for Lorentz, polarization and absorption ef-
fects with SADABS [8]. After completion of the data collections the
first 50 frames were repeated to check for decay of which none
was observed. The structures were solved by the heavy atom meth-
od and refined through full-matrix least squares cycles using the
2.4.2. trans-[PtCl(Me)(PPh3)2], 4
2
3
1H NMR: ꢀ0.09 (tt, 3H, 1 ꢁ CH3, JPt–H = 80 Hz, JP–H = 7 Hz),
7.3–7.4 (m, 18H, 18 ꢁ CH), 7.7–7.8 (m, 12H, 12 ꢁ CH). 31P: 29.36
1
(t, JPt–P = 3152 Hz).
SHELXL97 [9] software package with
R
(/Fo/ ꢀ /Fc/)2 being minimised.
All non-H atoms were refined with anisotropic displacement
parameters, the H atoms on the COD double bonds were placed
from the electron density map while all other H atoms were con-
strained to parent sites using a riding model. In both structures
the minimum and maximum residual electron densities were lo-
cated within 1 Å of the platinum atom. The graphics were done
with the DIAMOND [10] Visual Crystal Structure Information System
software. Crystal data, details of the data collection and refinement
parameters for 1, 2 and 10 are summarised in Table 1.
2.4.3. trans-[PtCl(Me)(PEt3)2], 5
2
3
1H NMR: 0.35 (tt, 3H, 1 ꢁ CH3, JPt–H = 84 Hz, JP–H = 6 Hz), 1.13
3
(t, 18H, 6 ꢁ CH3, JH–H = 8 Hz), 1.14–1.22 (m, 12H, 6 ꢁ CH2). 31P:
1
15.89 (t, JPt–P = 2820 Hz).
2.4.4. [Pt(Me)(l-Cl){P(NMe2)3}]2, 6
1H NMR: 0.46 (td, 3H, 1 ꢁ CH3, 2JPt–H = 82 Hz, JP–H = 1 Hz), 2.81
3
3
1
(t, 36H, 12 ꢁ CH3, JP–H = 5 Hz). 31P: 81.91 (t, JPt–P = 5675 Hz).

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S. Otto / Inorganica Chimica Acta 363 (2010) 3316–3320
Table 1
Crystallographic data and refinement parameters.
1
2
10
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
C9H15ClPt
353.75
Monoclinic
P21/n
7.8785(16)
10.782(2)
12.059(2)
90
C18H21ClFePt
523.74
Monoclinic
P21/n
10.725(2)
10.784(2)
14.166(3)
90
C46H39ClFeP2Pt
940.10
Monoclinic
P21/c
11.3272(4)
17.9844(7)
19.2067(8)
90
b (Å)
c (Å)
a
(°)
b (°)
103.20(3)
90
997.3(3)
4
2.356
14.28
101.44(3)
90
1605.7(6)
4
2.166
9.76
105.9530(10)
90
3762.0(3)
4
1.660
4.29
c
(°)
V (Å3)
Z
Dcalc (g cmꢀ3
)
l
(mmꢀ1
)
T (K)
293(2)
293(2)
293(2)
Tmax/Tmin
F(0 0 0)
0.462/0.217
656
0.239/0.106
1000
0.617/0.474
1864
Crystal size (mm)
h Limit (°)
Index ranges
0.13 ꢁ 0.13 ꢁ 0.05
2.56–28.28
ꢀ10 6 h 6 10
ꢀ14 6 k 6 14
ꢀ16 6 l 6 12
8891/2478
0.053
0.28 ꢁ 0.20 ꢁ 0.10
2.19–28.28
ꢀ13 6 h 6 14
ꢀ14 6 k 6 13
ꢀ18 6 l 6 18
13737/3986
0.054
0.26 ꢁ 0.09 ꢁ 0.09
2.19–28.28
ꢀ15 6 h 6 13
ꢀ23 6 k 6 21
ꢀ24 6 l 6 25
32808/9327
0.062
Reflections collected/unique
Rint
Observed reflections [I > 2
r
I]
1735
2804
6448
Data/restraints/parameters
Goodness-of-fit (GOF)
2478/0/119
0.956
0.0348
0.0859
0.0510
0.0921
1.311; ꢀ1.285
3986/0/207
0.936
0.0310
0.0655
0.0528
0.0711
0.770; ꢀ1.472
9327/0/461
1.031
0.0430
0.0982
0.0745
0.1060
0.707; ꢀ1.491
R (I > 2
r
I) Ra
wRb
R (all data) Ra
wRb
D
qmax
;
D
q
min/e Åꢀ3
a
R = [(
wR =
RDF)/(RFo)].
R
b
2
[w(Fo ꢀ Fc2)2]/
R
[w(Fo2)2]1/2
.
perspective, in having the two strongly coordination
r-donating
3. Results and discussion
Me groups in a cis arrangement outweighs the destabilisation of
having the bulky phosphine ligands next to each other.
3.1. Synthesis of complexes
In the present study the stepwise substitution of COD resulted
in both cis- and trans mononuclear complexes being obtained
depending on the nature of the phosphine. A Clꢀ bridged dimer
is observed as intermediate for <2 equivalents of the phosphine
in the sterically more demanding systems, i.e. Rꢀ = Me/
L = P(NMe2)3 and for Rꢀ = Fc/P = PEt3, PPh3 and P(NMe2)3, illustrat-
ing some resistance to accommodate a fourth bulky ligand in the
metal coordination sphere; this is in agreement with previous re-
ports of this nature [4]. In the case of the smaller, strongly coordi-
nating, PEt3 ligand the trans mononuclear complexes were
exclusively obtained in both cases.
The synthesis of [PtCl(Me)(COD)] and [PtCl(Fc)(COD)] is known
while trans-[PtCl(Me)(L)2] (L = PPh3 and P(NMe2)3) [11] and
trans-[PtCl(Fc)(PEt3)2] [12] have also been described before. The
COD complexes display two very characteristic sets of olefinic sig-
nals indicating different groups trans to the coordinated double
bonds of the COD moiety. The Pt–H coupling constants trans to
the R (Rꢀ = Me or Fc) group are significantly smaller than trans to
the Clꢀ in agreement with the larger trans influence of the
r–C
bond.
3.2. Solution studies
The species in solution were predominantly identified by their
very characteristic 31P NMR spectra displaying the expected Pt–P
coupling constants. It is well known that the Pt–P coupling con-
stants are diagnostic and can be used with a great deal of accuracy
to predict the geometries of complexes. In the case of the Me com-
plexes 1H NMR also proved useful due to the well resolved Me peak
[13]. Crystals of cis-[PtCl(Fc)(PPh3)2], 10, were obtained after slow
evaporation of the NMR sample containing more than 2 mol equiv-
alents of PPh3. Table 2 contains a summary of the product distribu-
tion for all the reactions investigated.
Table 2
Summary of the 31P NMR data for the product distribution of species in solution
during the reactions of [PtCl(R)(COD)] (Rꢀ = Me or Fc) with phosphines, L. Coupling
constants, in Hz, are given in brackets.
Rꢀ
L
[Pt(R)(
l
-Cl)(L)]2
cis-[PtCl(R)(L)2]
trans-[PtCl(R)(L)2]
Me
PPh3
Not observed
22.21 (4506)
26.99 (1726)
Not observed
78.52 (6158)
118.82 (2654)
29.36 (3152)
PEt3
P(NMe2)3
Not observed
81.91 (5675)
15.89 (2820)
108.63 (3902)
Nolan and co-workers previously reported on the substitution
of COD from [Pt(Me)2(COD)] with a variety of phosphines and in
all cases quantitative conversion was observed and cis-
[Pt(Me)2(L)2] was obtained as the only product [14]. The cis
geometry indicates that the stability gained, from an electronic
Fc
PPh3
15.26 (3614)
21.06 (4491)
24.52 (1698)
Not observed
75.50 (5907)
112.66 (1716)
30.42 (3343)
PEt3
P(NMe2)3
14.31 (4692)
78.91 (5411)
17.29 (2761)
101.34 (3854)

S. Otto / Inorganica Chimica Acta 363 (2010) 3316–3320
3319
3.3. Crystallography
Molecular diagrams showing the numbering scheme and ther-
mal ellipsoids are given in Figs. 1–3. Selected bond distances and
angles are summarised in Table 3.
All three crystal structures are composed of discrete molecules
with no significant interactions indicating that the packing is gov-
erned by van der Waals forces alone and not by electronic interac-
tions. No solvents molecules are present in any of the structures.
All three structures display the expected square planar geometry
and in all cases the Clꢀ and Rꢀ ligands are cis with respect to each
other.
A different polymorph of 1 has been reported previously [15]
with the crystal packing forces resulting in slight differences in
bond distances and angles. In both 1 and 2 the perpendicular
coordination mode of the COD double bonds with respect to the
equatorial plane are clearly illustrated by the C1–C2–Pt–Cl and
C5–C6–Pt–R torsion angles. The larger trans influences of Meꢀ
and Fcꢀ compared to Clꢀ is evident from the longer Pt–C1/C2 bonds
Fig. 3. Molecular diagram showing the numbering scheme and thermal displace-
ment ellipsoids (30% probability level) for cis-[PtCl(Fc)(PPh3)2]; hydrogen atoms
were omitted for clarity. In the numbering scheme of the PPh3 ligands the first digit
refers to the number of the ligand (1 or 2), the second to the number of the ring
(1–3) and the third to the number of the atom in the ring (1–6).
Table 3
Selected geometrical parameters for 1, 2 and 10.
Bond/angle
1/(Å)/(°)
2/(Å)/(°)
10/(Å)/(°)
Pt–Cl
2.316(2)
2.084(9)
2.3295(14)
2.026(5)
2.3658(14)
2.110(5)
Pt–Ra
Pt–P1
Pt–P2
2.3657(14)
2.2389(14)
Pt–C1
Pt–C2
Pt–C5
Pt–C6
C1–C2
C5–C6
R–Pt–Cl
P1–Pt–P2
Fc–Pt–P1
Fc–Pt–P2
Cl–Pt–P1
Cl–Pt–P2
C1–C2–Pt–Cl
C5–C6–Pt–Ra
C12–C11–Pt–Cl
2.280(8)
2.278(8)
2.134(10)
2.147(8)
1.347(14)
1.383(16)
88.3(4)
2.304(5)
2.291(6)
2.157(5)
2.152(5)
1.384(8)
1.398(8)
91.53(17)
Fig. 1. Molecular diagram showing the numbering scheme and thermal displace-
ment ellipsoids (30% probability level) for [PtCl(Me)(COD)]; hydrogen atoms are of
arbitrary size.
89.18(14)
97.64(5)
172.17(14)
89.52(14)
84.00(5)
174.26(6)
93.6(2)
95.6(2)
98.4(3)
96.2(4)
13.4(5)
27.6(3)
a
Rꢀ = Me, C(10), or Fc, C(11).
Table 4
Comparison of geometrical parameters for general [PtCl(R)(COD)] complexes.
Complex
Pt–Cl (Å)
Pt–COD (Å)
Pt–C (Å)
References
[PtCl2(COD)]
[PtCl(Me)(COD)]
2.312(1)
2.330(2)
2.170(6)
2.169(8)
2.282(8)
2.140(10)
2.279(8)
2.14(1)
[16]
[15]
2.164(8)
2.084(9)
2.017(9)
2.026(5)
2.033(5)
[PtCl(Me)(COD)]
[PtCl(Ph)(COD)]
[PtCl(Fc)(COD)]
[PtCl(Rc)(COD)]a
2.316(2)
2.327(3)
2.3295(14)
2.319(2)
This work
[17]
2.31(1)
2.155(5)
2.297(6)
2.141(6)
2.300(6)
This work
[18]
Fig. 2. Molecular diagram showing the numbering scheme and thermal displace-
ment ellipsoids (30% probability level) for [PtCl(Fc)(COD)]; hydrogen atoms are of
arbitrary size.
a
Rc = Ruthenocenyl.

3320
S. Otto / Inorganica Chimica Acta 363 (2010) 3316–3320
as compared to the PtC5/C6 bonds. As a result of the longer Pt–C1/
C2 bonds the back donation into the anti-bonding orbitals is also
less pronounced resulting in slightly shorter C1–C2 bonds as
compared to the C5–C6 bonds. The Fcꢀ moiety is orientated almost
perpendicular to the coordination plane as evident from the
C12–C11–Pt–Cl torsion angle of 13.4(5)°. The larger steric demand
of the Fcꢀ ligand as compared to Me is evident in R–Pt–Cl angles of
91.53(17)° and 89.3(4)°, respectively. Selected geometrical
parameters for related [PtCl(R)(COD)] complexes are presented in
Table 4.
the Pt–P bond distance trans to Fc significantly elongated as com-
pared to that trans of Clꢀ.
Acknowledgements
Financial support from the research fund of the University of
the Free State is gratefully acknowledged. Part of this material is
based on work supported by the South African National Research
Foundation under Grant Number (GUN 2053397). Any opinion,
finding and conclusions or recommendations in this material are
those of the authors and do not necessarily reflect the views of
the NRF. The University of Lund, Sweden, is gratefully acknowl-
edged for the use of their diffractometer.
In the structure of 10 the bulky PPh3 ligands were found to
adopt a cis arrangement indicating severe steric strain to be pres-
ent in the molecule. All angles deviate significantly from the ideal
90° with the P1–Pt–P2 angle 97.64(5)° resulting in compression of
the Cl–Pt–P1 angle at 84.00(5)°, see Table 3. Due to the larger trans
influence of Fcꢀ the Pt–P bond distances differ significantly at
2.3657(14) and 2.2389(14) Å respectively trans to Fcꢀ or Clꢀ. The
Fcꢀ moiety is deviating somewhat from the expected perpendicu-
lar coordination mode with a C12–C11–Pt–Cl torsion angle of
27.6(3)°. The direction of the tilt in the Fcꢀ orientation also sug-
gests steric congestion between the PPh3 and Fcꢀ groups in the
cis geometry.
Appendix A. Supplementary material
CCDC 765447, CCDC 765445 and 765446 contains the supple-
mentary crystallographic data for [PtCl(Me)(COD)], [PtCl(Fc)(COD)]
and cis-[PtCl(Fc)(PPh3)2]. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via www.ccdc.
cam.ac.uk/data_request/cif. Supplementary data associated with
this article can be found, in the online version, at doi:10.1016/
j.ica.2010.06.020.
A Pd structure, cis-[CpFe{
resembling 10, has been reported previously [19]. The compound
was obtained after the oxidative addition of [CpFe(
6-C6H5Cl)][-
g
6-[PdCl(PPh3)2]C6H5}][PF6], closely
g
References
PF6] to Pd(PPh3)4 and displays a mutual cis geometry of the PPh3
ligands similar to that found in 10.
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The stepwise substitution of COD from [PtCl(R)(COD)] (Rꢀ = Me
or Fc) by monodentate phosphine ligands, L (L = PEt3, PPh3 and
P(NMe2)3), were investigated in chloroform utilizing in situ 31P
NMR measurements. Addition of less than two molar equivalents
of the phosphine ligand results in the formation of dinuclear
molecules with the general formula trans-[Pt(R)(l-Cl)(L)]2 for the
sterically demanding systems where Rꢀ = Me/L = P(NMe2)3 and
Rꢀ = Fc/L = PEt3, PPh3 and P(NMe2)3 while larger quantities of the
ligands resulted in cis- and trans mixtures of the mononuclear
complexes. In the case of the strongly coordinating PEt3 ligand
the mononuclear trans-[PtCl(R)(PEt3)2] complex were exclusively
obtained in both cases. The crystal structures of the two substrates,
[PtCl(R)(COD)] (R- = Me or Fc), as well as the cis-[PtCl(Fc)(PPh3)2]
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