Carboxylation of (DPPF)-MCl2 [DPPF=1,1′- bis(diphenylphosphino)ferrocene; M=Pt or Pd] in aqueous and non-aqueous solutionCrystal and molecular structures of [Pt(C2O4)(DPPF)] and of [PtCl(NO3)(DPPF)]

Article abstract of DOI:10.1016/S0022-328X(03)00397-8

Treatment of the complexes [MCl₂(DPPF)] (M=Pt or Pd) {readily prepared in high yield from [MCl₂(DMSO)₂] (M=Pt (cis-) or Pd (trans-) and DPPF in CHCl₃} with two molar proportions of AgNO₃ in H₂

Full text of DOI:10.1016/S0022-328X(03)00397-8

Journal of Organometallic Chemistry 678 (2003) 48ꢂ55
/
www.elsevier.com/locate/jorganchem
Carboxylation of (DPPF)-MCl2 [DPPFꢀ
bis(diphenylphosphino)ferrocene; MꢀPt or Pd] in aqueous and non-
aqueous solution
/
1,1?-
/
Crystal and molecular structures of [Pt(C2O4)(DPPF)] and of
[PtCl(NO3)(DPPF)]
Talal A.K. Al-Allaf a,*, Harry Schmidt b, Kurt Merzweiler b, Christoph Wagner b,
Dirk Steinborn b
a Department of Chemistry, College of Basic Sciences, Applied Science University, Amman 11931, Jordan
b Institut fur Anorganische Chemie, Martin-Luther-Universitat Halle-Wittenberg, Kurt-Mothes-Str. 2, D-06112 Halle, Germany
¨
¨
Received 11 March 2003; accepted 27 April 2003
Abstract
Treatment of the complexes [MCl2(DPPF)] (Mꢀ
/
Pt or Pd) {readily prepared in high yield from [MCl2(DMSO)2] (MꢀPt (cis-) or
/
Pd (trans-) and DPPF in CHCl3} with two molar proportions of AgNO3 in H2O did not give the expected cation
[M(DPPF)(H2O)2]2ꢁ in solution. Instead the unusual homobimetallic bridged complex [{M(m-OH)(DPPF)}2](NO3)2 was formed
as an insoluble solvolysis solid product. Hence, carboxylation by addition of carboxylate anions to the solution cannot be carried
out by this method. In contrast, the complex [PtCl2(DPPF)] reacted readily with two molar proportions of AgOAc or one of
Ag2{1,1?-(OOC)2fc} (fcꢀ
/
ferrocene-2H) in acetone to give the corresponding carboxylato complexes. Other carboxylato complexes
were obtained from the reaction of the complexes [MCl2(DPPF)] and the K-salts of e.g. (COOH)2, CH2(COOH)2, and
ꢀ
ꢂ
CH2CH2CH2C(COOH)2 in H2O. With few exceptions, neither the K- nor the Ag-salts of the acids Me3CCOOH and C6H11COOH
react completely with [MCl2(DPPF)] in aqueous or non-aqueous solutions. However, the required products were obtained by
displacement of DMSO from the corresponding carboxylato complexes by DPPF in CHCl3. All of the new carboxylato complexes
and the solvolysis products were characterized physicochemically and spectroscopically. The X-ray structures of
[Pt{(OOC)2}(DPPF)] and of [PtCl(NO3)(DPPF)] were determined, to obtain some additional information on the coordination
mode of the unsymmetrical DPPF ligand in this type of complexes.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Platinum; Palladium; 1,1?-Bis(diphenylphosphino)ferrocene; Carboxylato complexes; NMR and X-ray studies; Structures
1. Introduction
reports were concerned with its coordination to metal
ions and the physical properties of the so formed
complexes, and only two articles described the solvolysis
behaviour of [PtCl2(DPPF)] in non-aqueous solutions.
One of them involved a determination of the X-ray
crystal structure of the solvolysis product [{Pt(m-
OH)(DPPF)}2](BF4)2 [7] and the other a study con-
cerned with its complexation with nucleosides [8]. The
The 1,1?-bis(diphenylphosphino)ferrocene (DPPF) li-
gand has received much attention in the past two
decades because it is a readily available versatile ligand
which coordinates smoothly with metal ions, and there
have been several reports of its complexes with transi-
tion and non-transition metals [1ꢂ6]. Almost all of these
/
carboxylato complexes of (DPPF)ꢂ
/
Pt or ꢂPd species
/
have been given less attention, probably because they
cannot be prepared by simple dechlorination of
[MCl2(DPPF)] with AgNO3 followed by addition of
* Corresponding author. Tel.:
5232899.
E-mail address: talal_al_allaf@hotmail.com (T.A.K. Al-Allaf).
ꢁ
/
962-6-5237181; fax:
ꢁ962-6-
/
0022-328X/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00397-8

T.A.K. Al-Allaf et al. / Journal of Organometallic Chemistry 678 (2003) 48ꢂ
/55
49
the carboxylate anion (vide infra). In view of this, and in
continuation of our previous work on a similar ligand,
viz. (diphenylphosphino)ferrocene [9], and of the car-
described by others [2], and proved to be faster and to
give higher yields and greater purity.
Equimolar quantities of [MCl2(DMSO)2] {MꢀPt
/
boxylation of [MCl2(DMSO)2] (Mꢀ
plexes in aqueous solutions [10], we decided to prepare
some new carboxylato complexes of the general formula
/
Pt or Pd) com-
(cis-) or Pd (trans-)} and the ligand DPPF in CHCl3
were heated gently for ca. 30 min with continuous
stirring. The clear solution was reduced in volume and
ether was added until precipitation was complete. The
solid thus formed was filtered off, washed several times
with ether, and dried in a vacuum-oven at 80 8C for
[M(OOCR)2(DPPF)], namely those with MꢀPt or Pd,
/
1
1
OOCRꢀ1
{(OOC)2CCH2CH2CH2},
/
=
2/(OOC)2,
=
2/(OOC)2CH2,
=
/
2
1
=
/
2{1,1?-(OOC)2fc} (fcꢀfer-
/
rocene-2H), OAc, (OOC)CMe3 and (OOC)C6H11 in
aqueous and non-aqueous media. Like other similar
complexes [1,2,4], the new carboxylato complexes are of
interest in a number of fields; the alteration of electron-
rich and electron-poor centers make them good candi-
dates for electrochemical and catalytic studies, for
example.
several hours. The yield was almost quantitative (ꢀ
90%).
/
2.4. [Pt{(OOC)2}(DPPF)] (3)
To a suspension of [PtCl2(DPPF)] (0.107 g, 0.13
mmol) in water (20 ml) was added a solution of
K2(OOC)2 (0.12 g, 0.67 mmol) in water (5 ml). The
mixture was heated under reflux for ca. 3 h then the
solid was filtered off, washed several times with water,
and dried in a vacuum-oven to constant weight. The
product was pure enough for further purposes, but it
2. Experimental
2.1. General
can be crystallized from chloroformꢂ
yellow crystals. Yield: 87%; m.p. 194 8C (dec.). Anal.
Found: C, 45.84; H, 3.28; C36H28FeO4P2Pt×H2O×CHCl3
(974.89) Calcd.: C, 45.58; H, 3.21%. n(CꢃO) 1704 and
1674 cmꢃ1, n(H2O) 3450 cmꢃ1
/
n-pentane as fine
The 1H- and 13C-NMR spectra were recorded on
Varian Unity 500 and Gemini 2000 spectrometers,
respectively, with CDCl3 as solvent and Me4Si as
internal reference. 31P-NMR spectra were recorded on
a Gemini 200 spectrometer with CDCl3 as solvent and
H3PO4 (85%) as external reference. The NMR spectra
and the elemental analyses were determined at the
/
/
/
.
The following complexes were prepared analogously
from the appropriate dichloro complex and potassium
salt:
[Pd{(OOC)2}(DPPF)] (4); m.p. 245 8C (dec.). Anal.
Institut fur Anorganische Chemie, Martin-Luther-Uni-
¨
¨
versitat Halle-Wittenberg, Germany. IR spectra were
Found: C, 56.83; H, 3.82. C36H28FeO4P2Pd×
(766.83) Calcd.: C, 56.39; H, 3.94%. n(CꢃO) 1710 and
1685 cmꢃ1, n(H2O) 3452 cmꢃ1
[Pt{(OOC)2CH2}(DPPF)] (5); m.p. 200 8C (dec.).
Anal. Found: C, 49.84; H, 3.94; C37H30FeO4P2Pt×
2H2O (887.56) Calcd.: C, 50.07; H, 3.86%. n(CꢃO)
1658 cmꢃ1, n(H2O) 3460 cmꢃ1
[Pd{(OOC)2CH2}(DPPF)] (6); m.p. 155 8C (dec.).
Found: C, 57.13; H, 3.95; C37H30FeO4P2Pd×H2O
(780.85) Calcd.: C, 56.91; H, 4.13%. n(CꢃO) 1653 (sh)
cmꢃ1, n(H2O) 3431 cmꢃ1
/H2O
/
recorded for KBr discs on a Pye-Unicam FT IR
spectrophotometer.
.
/
2.2. Starting materials
/
.
The salts PtCl2 and PdCl2, the free ligand 1,1?-
bis(diphenylphosphino)ferrocene (DPPF) and the acids
1,1-ferrocene dicarboxylic acid {1,1?-(HOOC)2fc},
/
/
CH3COOH,
(COOH)2×
/
2H2O,
CH2(COOH)2,
.
ꢀ
ꢂ
ꢀ
ꢂ
CH2CH2CH2C(COOH)2; C6H11COOH and Me3C-
COOH were commercial products and were used as
supplied. The Ag- and K-carboxylates were prepared by
adding one equivalent of AgNO3 or KOH for each
COOH group in ethanol until complete precipitation of
the salt occurred. The solid formed was filtered off,
washed with ethanol and ether, and dried under
/
[Ptf(OOC)2CCH2CH2CH2g(DPPF)] (7); m.p. 166 8C
(dec.). Anal. Found: C, 53.40; H, 4.16;
C40H34FeO4P2Pt×H2O (909.61) Calcd.: C, 52.82; H,
3.99%. n(Cꢃ
O) 1660 and 1636 cmꢃ1, n(H2O) 3450
cmꢃ1
/
/
.
2.5. [Pt{1,1?-(OOC)2fc}(DPPF)] (8)
vacuum. The yield in all cases was ꢀ
/80%.
The complex [PtCl2(DPPF)] (0.20 g, 0.24 mmol) was
dissolved in anhydrous acetone, Ag2{1,1?-(OOC)2fc}
(0.12 g, 0.25 mmol) was added, and the mixture was
stirred under reflux for ca. 2 h. The solvent was
evaporated off and the residual solid was extracted
with CHCl3. The extract was reduced in volume and
ether was added to the point of turbidity. The yellow
2.3. Preparation of complexes
The cis-[PtCl2(DMSO)2] and trans-[PdCl2(DMSO)2]
complexes were prepared as described previously [10].
The [PtCl2(DPPF)] (1) and [PdCl2(DPPF)] (2) com-
plexes were prepared by modification of the method

50
T.A.K. Al-Allaf et al. / Journal of Organometallic Chemistry 678 (2003) 48ꢂ55
/
solid formed was filtered off, washed with ether, and
dried under vacuum. Yield: 68%; m.p. 193 8C (dec.).
overnight. The solid formed was filtered off, washed
with ether, and dried in vacuum.
Anal. Found: C, 52.66; H, 3.83; C46H36 Fe2O4P2Pt×
/
Complex 12: Yield: 63%; m.p. 194 8C (dec.). Anal.
Found: C, 46.38: H, 3.58; N, 1.49; C68H58Fe2N2O8-
2H2O (1057.56) Calcd.: C, 52.24; H, 3.81%. n(Cꢃ
/
O)
1614 cmꢃ1, n(H2O) 3435 cmꢃ1. The complex had
evidently taken up water during the preparation or
work up and drying in a vacuum-oven for long time did
not change the elemental analysis.
P4Pt2×
/
CHCl3×
/
H2O (1794.40) Calcd.: C, 46.19; H, 3.43;
.
N, 1.56%. n(H2O) 3465 cmꢃ1
Complex 13: Yield: 57%; m.p. 164 8C (dec). Anal.
Found: C, 51.55; H, 3.89; N, 1.68; C68H58Fe2N2O8-
The complex [Pt(OAc)2(DPPF)] (9) was prepared
similarly; m.p. 182 8C (dec.). Anal. Found: C, 52.27;
H, 4.12; C38H34FeO4P2Pt (867.57) Calcd.: C, 52.61; H,
P4Pd2×
/
CHCl3×
/
H2O (1617.02) Calcd.: C, 51.25; H, 3.80;
.
N, 1.73%. n(H2O) 3435 cmꢃ1
Note: The yields of complexes 12 and 13 can be
enhanced by addition of equimolar quantity of the free
ligand DPPF to the reaction mixture.
3.95%. n(Cꢃ
/
O) 1623 cmꢃ1
.
2.6. [Pt(OOCCMe3)2(DPPF)] (10)
2.8. [PdCl(NO3)(DPPF)] (14)
This complex can be prepared as described for
complex 3 by prolonged refluxing of a mixture of an
excess of K(OOC)CMe3 and complex 1 in water until
complete conversion of the latter into the product.
However, the following method is superior:
This complex was prepared by a similar method to
that for 12 and 13 apart of using equimolar quantities of
the reactants [PdCl2(DPPF)] and AgNO3 in water.
Upon crystallization of the solid thus formed from hot
CHCl3, dark maroon crystals separated out suitable for
X-ray analysis. No further analyses were done on this
complex.
To a suspension of [PtCl2(DMSO)2] (0.106 g, 0.25
mmol) in water (10 ml) was added a solution of AgNO3
(0.085 g, 0.25 mmol) in H2O (5 ml). The stirred mixture
was heated at ca. 80 8C for 2 h then treated with a small
amount of charcoal and filtered hot. The filtrate was
added to a solution of K(OOC)CMe3 (0.125 g, 0.78
mmol) in water (2 ml) and the mixture was warmed for
few minutes then evaporated to dryness. The residual
pale yellow solid-gel was suspended in chloroform and
DPPF (0.14 g, 0.25 mmol) was added with stirring. The
yellow solution was filtered, the filtrate was reduced in
volume, and ether was added to the point of turbidity.
The solid formed was filtered off, washed with ether,
and dried in vacuum. Yield: 72%; m.p. 224 8C (dec.).
2.9. X-ray structure determination of 3 and 14
Crystals suitable for single-crystal diffraction analyses
of (3×
/
3CHCl3) and (14×CHCl3) were grown at 25 8C by
/
slow evaporation of their chloroform solutions. Inten-
sity data were collected on a STOE-IPDS diffractometer
˚
Ka radiation (lꢀ0.71073 A, graphite mono-
with Moꢂ
/
/
chromator) at 220(2) K. A summary of the crystal-
lographic data, the data collection parameters, and the
refinement parameters is given in Table 1. Absorption
corrections were carried out numerically (Tmin/Tmax
Anal. Found: C, 53.36; H, 4.67; C44H46FeO4P2Pt×
(987.76) Calcd.: C, 53.50; H, 5.10%. n(Cꢃ
O) 1625 cmꢃ1
n(H2O) 3417 cmꢃ1
/
2H2O
0.377/0.567, 3×
/
3CHCl3; 0.650/0.837, 14×
/
CHCl3). The
structures were solved by direct methods with SHELXS-
/
,
.
97 and refined using SHELXL-97 [11]. Non-hydrogen
atoms were refined with anisotropic displacement para-
meters. H atoms were found in the difference Fourier
The [Pt{(OOC)C6H11}2(DPPF)] (11) complex was
prepared similarly; m.p. 142 8C (dec). Anal. Found: C,
56.75; H, 5.34; C48H50FeO4P2Pt×
C, 56.42; H, 5.13%. n(Cꢃ
O) 1621 cmꢃ1, n(H2O) 3408
cmꢃ1
/H2O (1021.84) Calcd.:
map (3×
/
3CHCl3) and added to the model in their
/
calculated positions according to the riding model (14×
/
.
CHCl3), respectively. They were refined isotropically.
2.7. [{M(m-OH)(DPPF)}2](NO3)2 (Mꢀ
/
Pt, 12;
MꢀPd, 13)
/
3. Results and discussion
To a suspension of [MCl2(DPPF)] (0.19 mmol) in
water (20 ml) AgNO3 (0.063 g, 0.37 mmol) was added.
The stirred mixture was heated at 80 8C for 2 h, then
filtered hot. The colourless filtrate was evaporated and
It is well known that dechlorination of platinum(II) or
palladium(II) complexes of the type [MCl2L2], L2ꢀ
/
2DMSO or cyclohexane-1,2-diamine, by silver nitrate
in aqueous media leads to formation of the cation
[ML2(H2O)2]2ꢁ and this is converted into the corre-
sponding carboxylato complex upon treatment with
carboxylate ion [10,12]. However, when L2 was the
chelate 1,1?-bis(diphenylphosphino)ferrocene (DPPF),
the reaction of [MCl2(DPPF)] with silver nitrate (in
the residual yellowꢂorange solid was dried in vacuum
/
for several hours. It was dissolved in CHCl3 and the
solution was filtered to remove AgCl and the filtrate
reduced in volume. Ether was added to the point of
turbidity and the solution kept in the refrigerator

T.A.K. Al-Allaf et al. / Journal of Organometallic Chemistry 678 (2003) 48ꢂ
/55
51
Table 1
Crystal data and structure refinement for 3×
/
3CHCl3 and 14×CHCl3
/
[Pt{(OOC)2}-
(DPPF)]×3CHCl3
[PdCl(NO3)-
(DPPF)×CHCl3
/
/
(3×/3CHCl3)
(14×/CHCl3)
Empirical formula
Formula weight
T (K)
C39H31Cl9FeO4P2Pt C35H29Cl4FeNO3P2Pd
1195.57
220(2)
877.58
220(2)
Crystal system
Space group
Monoclinic
P21/c
Monoclinic
P21/n
˚
b (A)
18.904(3)
21.967(4)
93.73(2)
4383.7(13)
4
16.511(2)
17.279(4)
91.08(3)
3598.4(13)
4
˚
c (A)
b (8)
3
V (A )
˚
Z
Scheme 1. Possible routes to the (DPPF)ꢂ
/
Pt or ꢂ
/
Pd carboxylato
rcalc. (g cmꢃ3
)
1.812
4.180
1.620
1.325
complexes with the oxalate anion used as example.
m (Moꢂ
/
Ka) (mmꢃ1
)
Scan range 2U (8)
Reciprocal lattice
segments h, k, l
4.30ꢂ
120
220
260
27 292
8434 [Rint
/
51.92
4.04ꢂ
150
180
210
26 001
0.0615] 6480 [Rint
/
51.64
ꢃ
/
/
11,
23,
26
ꢃ
/
/
15,
18,
20
ꢃ
/
/
ꢃ
/
/
ꢃ/
/
ꢃ/
/
Reflections collected
Reflections
independent
water. This method was found to be effective when the
potassium salts of dicarboxylic acids, namely, oxalic
acid, malonic acid or 1,1-cyclobutane dicarboxylic acid
were used along with complexes precursors 1 or 2 and
the reactions were allowed to proceed for completion. In
the case of monocarboxylic acids, e.g. pivalic acid or
cyclohexane carboxylic acid, the formation of the
product is slower than that of the potassium dicarbox-
ylate and proceeds through the formation of an inter-
mediate complex, i.e. [PtCl(carboxylato)(DPPF)] (vide
infra). In the case of the salt K(OOC)C6H11, the reaction
with complex 1 did not go into completion and so a pure
product could not be obtained. These results were
monitored by 31P-NMR spectroscopy (vide infra). It is
evident that the most useful method is the third one,
(iii), involving a ligand displacement reaction. Thus the
platinum and palladium complexes 10 and 11 were
prepared by a simple displacement of DMSO by DPPF
in an organic solvent, e.g. chloroform. The platinum and
palladium carboxylato complexes of the ligand DPPF
prepared by the three methods (Scheme 1) have been
fully characterized. Their physical properties are re-
ꢀ
/
ꢀ0.1154]
/
Data/restrains/
parameters
8434/0/629
R1ꢀ0.0298
0.0714
6480/0/424
R1ꢀ0.0587
Final R indices [I ꢀ
2s(I)]
/
/
/
wR2ꢀ
R1ꢀ0.0440
wR2ꢀ0.0788
Largest difference peak 1.046, ꢃ0.793
/
wR2ꢀ
R1ꢀ0.1045
wR2ꢀ0.1688
0.880, ꢃ0.843
/0.1456
R indices (all data)
/
/
/
/
/
/
ꢃ3
˚
and hole (e A
)
1:1 molar ratio) in water was found to take a different
course and not to give the cation [M(DPPF)(H2O)2]2ꢁ
in solution. Thus carboxylation by addition of carbox-
ylate ion could not be achieved by this method. The
rather unusual homobimetallic hydroxo-bridged com-
plexes [{M(m-OH)(DPPF)}2](NO3)2, (Mꢀ
/
Pt (12); Mꢀ
/
Pd (13)) were obtained by the treatment of complexes 1
and 2 with silver nitrate in aqueous solution (Scheme 1).
Complexes 12 and 13 remained in the reaction mixture
as solids mixed with silver chloride and no metal ion
could be detected in the colourless filtrate (see Section
2). An X-ray diffraction analysis of complex [{Pt(m-
OH)(DPPF)}2](NO3)2 (12) could not be completely
solved due to severe disorder, but showed unambigu-
ously the topology of this complex as OH-bridged
dinuclear species.
1
ported in Section 2, with the H-, 31P-, and 13C-NMR
spectral data listed in Tables 2 and 3. All the palladium
complexes 2, 4, 6, and 13 are maroon in colour while the
platinum complexes 1, 3, 5, and 7ꢂ
/
12 are yellowꢂ
/
orange. Both the palladium and the platinum complexes
are stable solids in air and decompose only above
150 8C. With few exceptions, most of the complexes
were isolated from their solutions bearing water of
solvation, as is apparent from the broad bands in the
IR spectra at ca. 3450 cmꢃ1 due to n(H2O) and
confirmed by the appearance of the proton signals
Possible methods for the formation of carboxylato
complexes of the DPPF ligand are shown in Scheme 1.
The first (i) involves the reaction of the precursors 1 or 2
with silver carboxylate in dry acetone. The second (ii)
involves the reaction of the precursors 1 or 2 with the
potassium salt of an appropriate carboxylic acid in
1
from H2O as broad signals at d 1.64 ppm in the H-
NMR spectra (in CDCl3).

52
T.A.K. Al-Allaf et al. / Journal of Organometallic Chemistry 678 (2003) 48ꢂ55
/
Table 2
1H- and 31P{1H}-NMR data (d in ppm and J in Hz) for the complexes 1ꢂ
13
/
Complex
1H-NMR
31P-NMR
a
d(C5H4)
d(C6H5) b
d(Others) e
d
J(PtꢂP)
/
1
2
3
4
5
6
7
4.17, 4.34
4.18, 4.38
4.27, 4.45
4.30, 4.49
4.30, 4.44
4.33, 4.47
4.31, 4.43
7.37ꢂ
7.35ꢂ
7.33ꢂ
7.39ꢂ
7.38ꢂ
7.43ꢂ
7.38ꢂ
/
7.87
7.91
7.87
7.75
7.81
7.83
7.80
14.2 (13.06) c
3761.5 (3769) c
/
35.0 (34) c
9.6
/
3850
/
37.4
/
3.29s (CH2)
3.33s (CH2)
1.61t (CH2)
2.48q (CH2)2
4.37 d (C5H4)2
1.32s (CH3)
0.61s (CH3)3
8.3
36.6
3844
/
/
7.7
3844
8
9
4.10, 4.60
4.34 d
7.31ꢂ
7.30ꢂ
7.31ꢂ
7.29ꢂ
7.25ꢂ
7.31ꢂ
/
8.00
7.85
7.86
7.83
8.00
8.10
8.3
6.2
4016
3935
3941
3935
3824
/
10
11
12
13
4.30, 4.32
4.33 d
/
7.4
7.2
/
0.89ꢂ
/
1.55m (C6H11
)
4.24, 4.44
4.30, 4.48
/
10.3
38.7
/
a
Broad signals.
Multiplet signals.
b
c
Data obtained from Ref. [2] using CH2Cl2 as solvent.
Two signals are superimposed.
Abbreviations: s, singlet; t, triplet; q, quintet; m, multiplet.
d
e
3.1. NMR studies
The 31P{1H}-NMR spectra (Table 2) of all the
palladium complexes 2, 4, 6, and 13 each showed a
single signal expected for symmetrical phosphines while
1
The H-NMR spectra of all complexes 1ꢂ
/
13 revealed
8.0 ppm due to the
the presence of multiplets at 7.2ꢂ
/
those of the platinum complexes 1, 3, 5, and 7ꢂ
showed singlets and doublets (due to the Pt, H
couplings). The 1J(195Ptꢂ31
P) coupling constant of
/
12
phenyl protons and two broad signals at 4.2 and 4.5
ppm due to the protons of the cyclopentadienyl group.
These are in addition to the signals of the anion protons
if there are any (Table 2).
/
complex 1, 3761.5 Hz is typical for phosphine trans to
a chlorine atom, c.f. [PtCl2(DPPE)] 3621 Hz [13] and
Table 3
13C-NMR chemical shifts (d in ppm) of the complexes 1ꢂ
/
13 a
Complex
Phenyl
Cyclopentadienyl
Carboxylato
b
dC1
dC2/6 b dC3/5 b dC4 c dC1 b dC2/5 b dC3/4 b dCO d d(others)
1
2
131.5
131.4
128.5
128.9
128.5
128.6
128.7
130.0
129.9
130.1
130.0
127.2
127.2
135.5
135.5
134.2
134.4
134.3
134.5
134.4
135.1
134.4
134.4
134.4
133.5
133.5
128.4
128.6
128.7
129.3
128.7
128.8
128.5
128.5
128.1
128.0
128.0
128.8
128.7
131.7 73.4
131.7 73.3
132.0 71.0
132.1 71.3
132.0 70.5
132.1 70.6
76.4
76.7
76.0
76.5
75.8
76.3
75.8
76.7
76.2
76.3
76.3
76.3
76.3
74.2
74.3
74.3
74.5
74.3
74.4
74.2
74.1
73.5
73.4
73.4
74.7
74.7
3
166.8
166.8
172.6
173.2
176.3
175.5
176.3
182.1
180.3
4
5
50.3(CH2)
51.7(CH2)
6
e
7
131.9
131.7 70.5
131.0 71.8
55.6(C), 15.5 (CH2), 30.2(CH2)2
80.9(C1), 72.6(C2/3), 71.0(C4/5)
23.6(CH3)
8
9
e
10
11
12
13
130.8
40.2C(CH3)3, 28.0C(CH3)3
46.0(C1), 29.6 (C2/6), 25.8 (C3/5), 26.1(C4)
130.9 72.3
132.2 69.3
132.1 69.2
a
NMR data of 9: J(PP?), 20.8 Hz. Phenyl carbon atoms: dC1, 129.9 ppm; J(PC), 64.8 Hz; J(P?C), ꢃ
1.9 Hz. dC4, 131.0 ppm. Cyclopentadienyl carbon atoms: dC1, 71.8 ppm; J(PC), 70.3
Hz; J(P?C), 8.2 Hz. dC2/5, 76.2 ppm; J(PC), 13.8 Hz; J(P?C), ꢃ2.8 Hz. dC3/4, 73.5 ppm; J(PC), 10.1 Hz; J(P?C), ꢃ1.9 Hz. Acyl carbon atoms:
/
0.04 Hz. dC2/6, 134.4 ppm; J(PC), 10.9 Hz;
J(P?C), 0.8 Hz. dC3/5, 128.1 ppm; J(PC), 11.1 Hz; J(P?C), ꢃ
/
/
/
dCO, 176.3 ppm (broad). dCH3, 23.6 ppm; J(PC), 4.8 Hz; J(P?C), 0.8 Hz.
Multiplet signals.
b
c
Singlets.
Broad signal.
Signals obscured by the noise.
d
e

T.A.K. Al-Allaf et al. / Journal of Organometallic Chemistry 678 (2003) 48ꢂ
/55
53
[PtCl2(PPh3)2] 3679 Hz [14], and the coupling constants
for the platinum complexes with a carboxylato group,
i.e. with phosphine trans to oxygen, are higher than that
nyl groups in addition to those from the carboxylato
group. The spectra of the complexes are of the AA?X
form [15]. The AA? represent the two phosphine atoms
of DPPF and X represents the carbon atom of the
phenyl or the cyclopentadienyl. The 13C-NMR chemical
shifts for all the complexes are listed in Table 3 but no
coupling constants are shown since the 13C-NMR data,
calculated with the computer programme PERCH [16],
for complex 9, i.e. [Pt(OAc)2(DPPF)], represent a model
for the rest of complexes (footnote Table 3).
for complex 1 by ca. 100ꢂ/250 Hz (Table 2) reflecting
electronegativity effects.
Unexpectedly, the 31P-NMR spectrum of the solid
obtained from the reaction between complex 1 and a
large excess of K(OOC)CMe3 in H2O under reflux for
ca. 3 h, revealed the presence of, in addition to the
platinum starting material (10%) and the product 10
(14%), a complex (76%) with parameters, d 3.2 ppm;
1
1J(PtP) 3682.5 Hz and d 18.0 ppm; J(PtP) 4076.1 Hz;
3.2. Crystal structures of 3 and 14
2J(PP) 15.5 Hz. The first coupling constant is typical for
phosphine trans to chlorine and the second for phos-
phine trans to oxygen, and they are tentatively assigned
to the intermediate complex [PtCl{(OOC)CMe3}-
(DPPF)]. The latter was converted (100%) into the
dicarboxylato complex 10 upon more prolonged reflux-
ing of the reaction mixture. Similarly, 31P-NMR spec-
troscopy showed that the reaction of complex 1 with a
large excess of K(OOC)C6H11 in water under reflux for
ca. 3 h gave a solid containing unchanged 1 (80%) and a
new complex (20%) with the parameters d 3.3 ppm;
1J(PtP) 3673 Hz and d 18.4 ppm; 1J(PtP) 4074 Hz;
2J(PP) 16.2 Hz. These parameters are tentatively
assigned to the monocarboxylato complex, i.e.
[PtCl{(OOC)C6H11}(DPPF)]. When the mixture with
an excess of K(OOC)C6H11 was refluxed further for
about 3 h, the 31P-NMR spectrum of the solid revealed
that the proportion of the monocarboxylato complex
increased to 32%. None of the dicarboxylato complex 11
was detected even after more prolonged refluxing.
However, the dicarboxylato complex 11, like the other
complexes can be obtained in a pure form by treating
Single crystals of the oxalato complex [Pt{(OOC)2}-
(DPPF)]×
/
3CHCl3 (3×/3CHCl3) were obtained by the
crystallization of the complex from chloroform in well
shaped orange crystals. The molecular structure is
shown in Fig. 1, selected bond lengths and angles are
given in Table 4. The platinum atom is coordinated by
two oxygen atoms of the oxalato ligand and two
phosphorous atoms of the DPPF ligand. The [PtO2P2]
unit and the oxalato ligand (COO)2 are planar in good
approximation (greatest deviations from the mean plane
˚
0.028(3) A for O3 and 0.046(3) A for O2, respectively).
˚
Both planes are nearly coplanar (interplanar angle:
6.1(1)8). The ‘bite’ of the DPPF ligand causes a P1ꢄ
PtꢄP2 angle of 97.42(4)8 that is in the expected range
(PꢄMꢄP?, Mꢀtransition metal: median 99.08, lower/
upper quartile 97.9/100.88, 25 observations [17]). Due to
that the opposite O1ꢄPtꢄO2 angle (81.1(1)8) is lowered
and is in the expected range for OꢄMꢄO? angles of
/
/
/
/
/
/
/
/
/
transition metal oxalato complexes (median 81.78,
lower/upper quartile 76.3/84.28, 546 observations [17]).
The ferrocene moiety is staggered (P1ꢄ
35.1(2)8). As expected the CꢄO bonds coordinated to
platinum are much longer than the non-coordinated
/
C3ꢀ ꢀ ꢀC8ꢄ/P2
the
corresponding
DMSO
complex,
i.e.
/
[Pt{(OOC)C6H11}2(DMSO)2] [10] with DPPF in chloro-
form.
˚
ones (1.289(6)/1.302(6) vs. 1.216(6)/1.217(6) A). In the
solid state, two of the three chloroform molecules are
We believe that the reaction of complex 1 or 2 with
silver nitrate in water to give the dimeric complex 12 or
13 probably takes place in through two steps, the first
step involving the removal of one chlorine atom and the
second step the removal of the second chlorine atom.
This was tentatively confirmed by the formation of a
complex with the 31P-NMR parameters d 3.4 ppm;
involved in hydrogen bonds Cꢃ
/
Oꢀ ꢀ ꢀHCCl3 to the non-
coordinated oxygen atoms of the oxalato ligand (Fig. 1):
1
1J(PtP) 3843.7 Hz and d 18.4 ppm; J(PtP) 3965.0 Hz;
2J(PP) 15.4 Hz, which are consistent with the presence
of two different phosphine nuclei, with the lower J value
being for phosphine trans to chlorine and the higher J
value for phosphine trans to oxygen. The complex is
most likely to be [Pt2(m-Cl)(m-OH)(DPPF)2](NO3)2.
However, we have not attempted to isolate any of the
three intermediates, [PtCl{(OOC)CMe3}(DPPF)], [PtCl-
{(OOC)C6H11}(DPPF)],
(DPPF)2](NO3)2.
and
[Pt2(m-Cl)(m-OH)-
The 13C-NMR spectra (Table 3) of all complexes 1ꢂ
13 showed signals due to the phenyl and cyclopentadie-
/
Fig. 1. Solid-state structure of crystals of [Pt{(OOC)2}(DPPF)]
3CHCl3 (3×3CHCl3). One solvate molecule is omitted for clarity.
/

54
T.A.K. Al-Allaf et al. / Journal of Organometallic Chemistry 678 (2003) 48ꢂ55
/
Table 4
Table 5
Selected bond lengths (in A) and angles (in 8) for [PdCl(NO3)(DPPF)]×
CHCl3 (14×CHCl3)
˚
˚
Selected bond lengths (in A) and angles (in 8) for
[Pt{(OOC)2}(DPPF)]×3CHCl3 (3×3CHCl3)
/
/
/
/
Bond lengths
Bond lengths
Ptꢄ
Ptꢄ
Ptꢄ
Ptꢄ
C1ꢄ
/
O1
O2
P1
P2
2.062(3)
2.065(3)
2.241(1)
2.247(1)
1.563(6)
C1ꢄ
C1ꢄ
C2ꢄ
C2ꢄ
Feꢄ
/
O1
O3
O2
O4
1.302(6)
1.216(6)
1.289(6)
1.217(6)
Pdꢄ
Pdꢄ
Pdꢄ
Pdꢄ
/
Cl1
O1
P1
2.360(2)
2.100(5)
2.290(2)
2.275(2)
Nꢄ
Nꢄ
Nꢄ
Feꢄ
/
O1
O2
O3
1.267(9)
1.236(9)
1.266(8)
/
/
/
/
/
/
/
/
/
/
/P2
/
C
1.985(8)ꢂ2.064(9)
/
/
C2
/
C
2.012(5)ꢂ2.093(5)
/
Bond angles
P2
Bond angles
P1ꢄPtꢄP2
O1ꢄPtꢄ
O1ꢄPtꢄ
O1ꢄPtꢄ
P1ꢄ
Cl1ꢄ
O1ꢄPdꢄ
O1ꢄPdꢄ
/
Pdꢄ
/
98.63(7)
86.2(2)
89.3(2)
Cl1ꢄ
Cl1ꢄ
PdꢄP1ꢄ
PdꢄP2ꢄ
/
Pdꢄ
Pdꢄ
/
P1
173.26(8)
86.65(8)
116.2(3)
122.8(2)
/
/
97.42(4)
81.1(1)
O2ꢄ
O2ꢄ
PdꢄPtꢄ
PdꢄPtꢄ
/
Ptꢄ
Ptꢄ
/
P1
173.08(9)
89.17(9)
114.1(2)
123.3(2)
/
Pdꢄ
/
O1
/
/P2
/
/
O2
P1
P2
/
/P2
/
/
P1
P2
/
/
C1
/
/
92.37(9)
170.22(9)
/
/C3
/
/
167.7(2)
/
/
C6
/
/
/
/C8
4. Supplementary material
So the Cl3C39ꢄ
/
H molecule acts as hydrogen donor for a
Hꢀ ꢀ ꢀO4: Hꢀ ꢀ ꢀO4
Hꢀ ꢀ ꢀO4 1578; C39ꢄHꢀ ꢀ ꢀO3: Hꢀ ꢀ ꢀO3
Hꢀ ꢀ ꢀO3 1338) whereas the Cl3C38ꢄ
molecule acts as a two-center hydrogen bond (C38ꢄ
three-center hydrogen bond (C39ꢄ
/
Crystallographic data (excluding structure factors)
have been deposited at the Cambridge Crystallographic
Data Center, CCDC nos. 208350 and 208349 for
˚
2.31(6) A, C39ꢄ
/
/
˚
2.51(6) A, C39ꢄ
/
/
H
/
compounds 3×
/
3CHCl3 and 14×
/
CHCl3. Copies of this
˚
Hꢀ ꢀ ꢀO3: Hꢀ ꢀ ꢀO4 2.22(7) A, C38ꢄ
these values are within the geometrical cut-offs given for
CꢃOꢀ ꢀ ꢀHꢄ hydrogen bonds [18]. The complex
[PdCl(NO3)(DPPF)] (14) crystallized from chloroform
as 14×CHCl3 in well shaped dark maroon crystals. The
/
Hꢀ ꢀ ꢀO3 1568). All of
information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2 1EZ,
/
/C
UK (Fax: ꢁ44-1223-336-033; e-mail deposit@ccdc.
/
cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
/
X-ray structure analysis revealed that there are no
unusual intermolecular interactions between the com-
plex and the solvate molecule (shortest intermolecular
contact between non-hydrogen atoms: C31ꢀ ꢀ ꢀCl4
Acknowledgements
T.A.K. Al-Allaf would like to thank the Alexander
von Humboldt-Stiftung for supporting this research.
˚
3.336(4) A). The molecular structure of 14 is shown in
Fig. 2, selected bond lengths and angles are given in
Table 5. The geometry of the Pd(DPPF) fragment is
essentially the same as that in complex 3×
/
3CHCl3 (P1ꢄ
/
References
PtꢄP2 98.63(7)8, P1ꢄ P2 32.6(4)8). There is a
/
/
C1ꢀ ꢀ ꢀC6ꢄ
/
substantial deviation of the [PdClOP2] moiety from
planarity: The greatest deviation from the mean plane
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˚
amounts to 0.159(6) A for O1. The nitrato ligand is
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F.R. Kreissl, Inorg. Chim. Acta 157 (1989) 259.
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[3] L. Tee Phang, S.C.F. Au-Yeung, T.S. AndyHor, S. Beng Khoo,
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[7] B. Longato, G. Pilloni, G. Valle, B. Corain, Inorg. Chem. 27
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/
CHCl3 (14×
/
¨
¨
CHCl3). The solvate molecule is omitted for clarity.
Germany, 1997.

T.A.K. Al-Allaf et al. / Journal of Organometallic Chemistry 678 (2003) 48ꢂ
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/