Unsymmetrical complexes containing the linear tetraphosphine ligand DPPEPM

Article abstract of DOI:10.1016/j.jorganchem.2005.09.021

The tetraphosphine DPPEPM reacts with [PtMe₂(cod)] to produce [PtMe₂(DPPEPM-PP)] (1) in near quantitative yield. On standing in solution, the free P atoms become oxidized to give [PtMe₂(DPPEPM(O) ₂-PP)] (1a), which has been characterized by X-ray crystallography. In contrast, reactions of DPPEPM with [MCl₂(cod)] (M = Pd, Pt) yield ionic products of the form [M(DPPEPM-PP)₂]MCl₄ (3, 4). When a solution of the platinum complex was allowed to stand, crystals of [Pt(μ-Cl)(μ-DPPEPM)₂]Cl₃ (5) were obtained. In a third set of reactions, treatment of [PtClR(cod)] (R = Me, Ph) or [PdClMe(cod)] with DPPEPM gives species of the type [MR(DPPEPM-PPP)]Cl (6-8), in which one of the internal P atoms is uncoordinated. Reactions of [PtR₂(DPPEPM-PP)] with [PtR2′(cod)] or [MCl₂(cod)] (M = Pd, Pt), or of [PtR(DPPEPM-PPP)]Cl with [MCl₂(cod)], lead to unsymmetrical bimetallic complexes. [PtMe₂(μ-DPPEPM)PdCl₂] (11) and [PtClPh(μ-DPPEPM)PdCl₂] (14) have been characterized crystallographically. Trimetallic complexes of the form [{PtR ₂(μ-DPPEPM)}₂M][MCl₄] (M = Pd, Pt, 15-17) are produced by reaction of [PtR₂(DPPEPM-PP)] with [MCl ₂(cod)].

Full text of DOI:10.1016/j.jorganchem.2005.09.021

Journal of Organometallic Chemistry 691 (2006) 529–537
www.elsevier.com/locate/jorganchem
Unsymmetrical complexes containing the linear
tetraphosphine ligand DPPEPM
Padma Nair, Colin P. White, Gordon K. Anderson ,1, Nigam P. Rath
*
Department of Chemistry and Biochemistry, University of Missouri-St. Louis, One University Boulevard, St. Louis, MO 63121, United States
Received 7 December 2004; received in revised form 15 September 2005; accepted 15 September 2005
Available online 26 October 2005
Abstract
The tetraphosphine DPPEPM reacts with [PtMe2(cod)] to produce [PtMe2(DPPEPM-PP)] (1) in near quantitative yield. On standing
in solution, the free P atoms become oxidized to give [PtMe2(DPPEPM(O)2-PP)] (1a), which has been characterized by X-ray crystal-
lography. In contrast, reactions of DPPEPM with [MCl2(cod)] (M = Pd, Pt) yield ionic products of the form [M(DPPEPM-PP)2]MCl4
(3, 4). When a solution of the platinum complex was allowed to stand, crystals of [Pt(l-Cl)(l-DPPEPM)2]Cl3 (5) were obtained. In a
third set of reactions, treatment of [PtClR(cod)] (R = Me, Ph) or [PdClMe(cod)] with DPPEPM gives species of the type
[MR(DPPEPM-PPP)]Cl (6–8), in which one of the internal P atoms is uncoordinated. Reactions of [PtR2(DPPEPM-PP)] with
½PtR02ðcodÞꢀ or [MCl2(cod)] (M = Pd, Pt), or of [PtR(DPPEPM-PPP)]Cl with [MCl2(cod)], lead to unsymmetrical bimetallic complexes.
[PtMe2(l-DPPEPM)PdCl2] (11) and [PtClPh(l-DPPEPM)PdCl2] (14) have been characterized crystallographically. Trimetallic com-
plexes of the form [{PtR2(l-DPPEPM)}2M][MCl4] (M = Pd, Pt, 15–17) are produced by reaction of [PtR2(DPPEPM-PP)] with
[MCl2(cod)].
Ó 2005 Elsevier B.V. All rights reserved.
Keywords: Platinum and palladium complexes; Crystal structure(s); Tetraphosphine ligands
1. Introduction
reactions have been observed, the drawback to this high
complex stability is that dppm-bridged species rarely exhi-
bit catalytic activity.
It has been reasoned that use of a linear tetraphos-
phine, which is capable of both bridging and chelating
functions, should confer greater reactivity on a bimetallic
system by maintaining a cis orientation of the remaining
groups coordinated to the metals. Indeed, rhodium
Diphosphine ligands such as bis(diphenylphosph-
ino)methane (dppm) have been used for nearly 30 years
in the construction of bimetallic complexes [1–6]. A range
of structures has been identified and a wealth of reaction
chemistry has been uncovered. The usually observed trans
arrangement of phosphine units leads to good complex sta-
bility [7–13]. We have been able to prepare a series of ther-
mally stable hydridopalladium (II) derivatives bridged by
dppm ligands [14–18], for example, whereas palladium
(II) hydrides are generally observed only as unstable reac-
tion intermediates. Although a number of well-defined
complexes
containing
bis{(diethylphosphinoethyl)
phenylphosphino}methane ligands have been shown to
be more effective hydroformylation catalysts than their
monomeric analogues [19]. We have reported previously
the synthesis and structures of symmetrical, bimetallic
complexes of platinum and palladium containing the
bis{(diphenylphosphinoethyl)phenylphosphino}methane
(DPPEPM) ligand [20]. We report here on approaches
to unsymmetrical, heterobimetallic complexes with
DPPEPM. A preliminary report of some of this work
has appeared [21].
*
Corresponding author. Tel.: +423 439 5671; fax: +423 439 4645.
E-mail address: andersgk@etsu.edu (G.K. Anderson).
Present address: Office of the Dean, College of Arts and Sciences, Box
1
70730, East Tennessee State University, Johnson City, TN 37614, United
States.
0022-328X/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.09.021

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P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
P
P
P
P
PtR2(cod)
MClR(cod)
MCl2(cod)
P
P
P
P
P
P
P
+
Pt
M
R
R
R
P
P
P
P
P
1, 2
+
2
6-8
M
P
P
P
P
3, 4
Scheme 1.
2. Results and discussion
When the DPPEPM ligand is allowed to react with
2 mol equiv. of [MCl2(cod)] (M = Pd, Pt) or [PtR2(cod)],
the products are symmetrical, bimetallic complexes of the
form [M2X4(l-DPPEPM)] [20]. In contrast, when 1 mol
equiv. of [PtR2(cod)] (R = Me, Ph) is added slowly to a
suspension of meso-DPPEPM in acetone, monometallic
complexes of the form [PtR2(DPPEPM-PP)] (1, R= Me;
2, R = Ph) are obtained in nearly quantitative yield (small
amounts of [Pt2R4(l-DPPEPM)] are also formed, and
these are difficult to separate, making it difficult to obtain
satisfactory microanalyses) (Scheme 1). If the addition is
performed in reverse order, i.e., if DPPEPM is added to
[PtR2(cod)], mixtures of products are obtained. In 1, for
example, the 31P{1H} NMR spectrum consists of four res-
onances, two arising from the P atoms coordinated to plat-
inum (with couplings to 195Pt of ca 1800 Hz, typical of P
atoms lying trans to alkyl substituents), and two that have
low frequency chemical shifts similar to those found in the
O
O
P
P
P
P
1
free ligand. The H NMR spectrum exhibits two signals
Pt
due to the non-equivalent methyl groups, and the signals
expected for the DPPEPM ligand. The high-resolution
mass spectrum reveals the presence of the parent ion, as
well as peaks associated with single oxidation of the parent.
Crystals formed on standing in chloroform solution, and
these proved to be of the double oxidation product
[PtMe2(DPPEPM(O)2-PP)] (1a). The uncoordinated P
atoms in 1 could be deliberately oxidized using elemental
sulfur, giving rise to [PtMe2(DPPEPM(S)2-PP)] (1b), a spe-
cies that exhibits four high frequency 31P resonances.
The molecular structure of 1a is shown in Fig. 1 and se-
lected bond distances and angles are presented in Table 1.
The structure reveals that two P atoms are coordinated to
platinum, whereas the other two have been oxidized. The
geometry at platinum is approximately square planar, the
sum of the angles about the metal center being 360.1°.
The larger angles are those between P and C atoms,
whereas the smallest angle (83.8°) is that between the smal-
ler methyl groups. The Pt–P and Pt–C distances are unre-
markable. The central P–C–P angle in the ligand is
116.0(4)°, similar to that found in DPPEPM(S)4 [20].
CH3
CH3
Fig. 1. Molecular structure of 1a, with atoms represented by thermal
ellipsoids at the 50% level.
Table 1
˚
Selected bond distances (A) and angles (°) for 1a
Pt–C(1)
Pt–P(1)
P(3)–O(1)
2.095(8)
2.263(2)
1.450(8)
Pt–C(2)
Pt–P(2)
P(4)–O(2)
2.095(9)
2.254(2)
1.410(8)
C(1)–Pt–C(2)
C(1)–Pt–P(2)
C(2)–Pt–P(2)
P(2)–C(5)–P(3)
83.8(4)
175.8(2)
92.7(3)
C(1)–Pt–P(1)
C(2)–Pt–P(1)
P(1)–Pt–P(2)
97.3(2)
179.0(3)
86.28(8)
116.0(4)
Obviously, this compound is generated by slow air oxida-
tion of 1, and it provides further evidence for the formation
of the monometallic species.
We anticipated that when 1 mol equiv. of [MCl2(cod)]
(M = Pd, Pt) was introduced similarly to an acetone suspen-
sion of DPPEPM it might form an analogous monometallic

P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
531
complex of the form [MCl2(DPPEPM-PP)]. The major
product does indeed show signals due to coordinated and
uncoordinated P atoms in its 31P NMR spectrum, but it is
1
clear from the JPtP values in the platinum complex that
the coordinated P atoms lie trans to other P atoms rather
than chlorides. The free P atoms appear at ꢁ12.7 and
ꢁ27.7, whereas the coordinated P atoms are observed at
34.3 (1JPtP = 2370 Hz) and 44.7 (1JPtP = 2665 Hz). Thus,
the cation is postulated to be [Pt(DPPEPM-PP)2]2+ (4)
(Scheme 1), and this has been confirmed by its high-
resolution mass spectrum. The palladium complex (3)
exhibits similar 31P NMR data. In each case, the 1H NMR
spectrum exhibits two widely spaced, broad resonances
due to the central CH2 group of the DPPEPM ligand.
With 31P-decoupling, these simplify to doublets, with
2JHH = 16 Hz. In the case of 4, these signals appear at 0.87
and 4.55 ppm, whereas they are observed at 0.91 and
4.35 ppm in the palladium analogue 3. The origin of this dis-
parity is unclear. In 4, eight resonances may be detected for
the PCH2CH2P hydrogens, and these may be separated into
two sets of four hydrogens based on COSY experiments.
Whereas the identity of the cation in each of these reac-
P
P
P
P
P
P
Pt
Pt
Cl
P
P
Fig. 2. Molecular structure of 5, with atoms represented by thermal
ellipsoids at the 50% level. Hydrogen atoms have been omitted for clarity.
1
tions has been established, the anion is invisible to H and
31P NMR spectroscopy. Although [MCl2(cod)] and
DPPEPM were allowed to react in a 1:1 ratio, the cations
contain two ligands per metal. This might suggest that half
of the metal precursor should be left unreacted, but moni-
toring the reaction by 1H NMR spectroscopy indicated
that no [MCl2(cod)] remained. Consistent with this obser-
vation, when 2 mol equiv. of DPPEPM was added to
[PtCl2(cod)], half of the ligand remained unreacted. Thus,
DPPEPM and the metal complex react in a 1:1 ratio, and
we suggest that the anions are PtCl24ꢁ and PdCl42ꢁ. The col-
ors of the reaction solutions range from yellow in the case
of platinum, to orange for palladium, which might be con-
sistent with the presence of the tetrachlorometallates. The
isolated complexes are off-white and yellow, respectively,
but these may not contain the MCl24ꢁ ions (vide infra). Sev-
eral attempts to detect PtCl24ꢁ by 195Pt NMR spectroscopy
were unsuccessful, perhaps due to the low solubility of the
complex. Attempts to identify the anion using negative ion
FAB mass spectrometry were also inconclusive, perhaps
due to decomposition of the anion in the solvent used (ace-
tonitrile). Thus, we can only infer the nature of the anion
from stoichiometry and further reaction, rather than by di-
rect observation.
Table 2
˚
Selected bond distances (A) and angles (°) for 5
Pt(1)–Cl
2.852(2)
2.357(2)
2.323(2)
2.319(2)
2.344(2)
Pt(2)–Cl
2.775(2)
2.358(2)
2.323(2)
2.308(2)
2.339(2)
Pt(1)–P(1)
Pt(1)–P(2)
Pt(1)–P(3)
Pt(1)–P(4)
Pt(2)–P(5)
Pt(2)–P(6)
Pt(2)–P(7)
Pt(2)–P(8)
Pt(1)–Cl–Pt(2)
P(1)–Pt(1)–P(2)
P(1)–Pt(1)–P(3)
P(1)–Pt(1)–P(4)
P(2)–Pt(1)–P(3)
P(2)–Pt(1)–P(4)
P(3)–Pt(1)–P(4)
P(1)–Pt(1)–Cl
P(2)–Pt(1)–Cl
P(3)–Pt(1)–Cl
P(4)–Pt(1)–Cl
P(2)–C(9)–P(7)
109.91(7)
81.90(8)
175.34(9)
99.02(8)
94.72(8)
173.83(8)
84.01(8)
81.51(8)
85.06(7)
101.46(8)
101.11(7)
122.7(5)
P(5)–Pt(2)–P(6)
P(5)–Pt(2)–P(7)
P(5)–Pt(2)–P(8)
P(6)–Pt(2)–P(7)
P(6)–Pt(2)–P(8)
P(7)–Pt(2)–P(8)
P(5)–Pt(2)–Cl
P(6)–Pt(2)–Cl
P(7)–Pt(2)–Cl
P(8)–Pt(2)–Cl
P(3)–C(10)–P(6)
80.76(8)
173.44(8)
100.41(8)
94.02(8)
171.36(9)
84.15(8)
80.99(8)
86.07(7)
102.74(8)
102.57(8)
123.3(5)
selected bond distances and angles are given in Table 2.
The cation is composed of two platinum centers, each of
which exhibits approximately square pyramidal geometry.
Each platinum is chelated by two PCH2CH2P units from
two different DPPEPM ligands in the square plane, the ax-
ial site being occupied by the chloride, which bridges the
two metals. The PtP4 units are nearly planar, the sums of
the angles about platinum being 359.3° and 359.7°. The
Attempts to grow crystals of 3 or 4 as their MCl24ꢁ salts
were unsuccessful. When a chloroform solution of the plat-
inum complex was allowed to evaporate slowly, yellow
crystals were obtained, but these proved to be of a bimetal-
lic complex [Pt2(l-Cl)(l-DPPEPM)2]Cl3 (5). This has the
same overall formulation, and evidently it is produced by
a complex rearrangement of [(4)]PtCl4, involving displace-
ment of chlorides from PtCl24ꢁ by attack of the free P atoms
of the cation. One of the chlorides remains coordinated and
assumes a bridging role. The molecular structure of the
[Pt2(l-Cl)(l-DPPEPM)2]3+ cation is shown in Fig. 2, and
˚
platinum atoms are located 0.096 and 0.131 A out of the
mean plane of their four P atoms. The two P4 planes are
inclined at an angle of 62°, and this results in two smaller
(80.99(8)–86.07(7)°) and two larger (101.11(7)–102.74(8)°)
P–Pt–Cl angles at each platinum. The Pt–Pt distance is
˚
4.61 A. The Pt–P distances range from 2.308(2) to
˚
2.358(2) A, and the P–Pt–P angles range from 80.76(8)°
to 100.41(8)°. The smaller angles are found for the chelated

532
P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
diphosphine units. The chloride bridges the two metals in
an unsymmetrical fashion (Pt–Cl 2.775(2) and 2.852
(2) A), with a Pt–Cl–Pt angle of 109.91(7)°. This angle is
P
P
P
P
˚
Pt
Me
considerably greater than those found in dppm-bridged
complexes [22]. The P–C–P angles are much greater at
122.7(5)° and 123.3(5)° than in previously characterized
complexes [20], perhaps due to the need to maintain the
two PtP4 units at an optimal distance from one another,
and this may involve some strain within the tetraphosphine
ligands. Very few solid state structures have been reported
for five-coordinate platinum or palladium complexes with
four P atoms and one chloride in their coordination sphere
[23–29], and this represents the first in which the chloride
serves as a bridging ligand.
Me
1
PtPh2(cod)
MCl2(cod)
P
P
P
P
P
P
P
P
Pt
Pt
Pt
M
Ph
Me
Me
Ph
Cl
Me
Me
Cl
9
10,11
Reactions of [PtClR(cod)] (R = Me, Ph) or [PdClMe-
(cod)] with DPPEPM follow a third pathway to give 6–8.
When the metal complex is allowed to react with 1 mol
equiv. of DPPEPM, the chloride is displaced and
DPPEPM acts as a tridentate ligand, with one of the inter-
nal P atoms remaining uncoordinated (Scheme 1). On
standing in solution, this free P atom becomes oxidized.
The solid state structure of [PtMe(DPPEPM(O)-PPP)]Cl
has been determined [21], and peaks due to the oxidized
product are found in the mass spectrum of [PtMe(DP-
PEPM-PPP)]Cl (6) and in the 31P NMR spectrum of
[PdMe(DPPEPM-PPP)]Cl (8). The 31P NMR spectra of
the [MR(DPPEPM-PPP)]+ cations contain four reso-
nances, one at low frequency due to the uncoordinated P
Scheme 2.
2
atom, two that exhibit large JPP coupling constants (ca
380 Hz) indicative of their mutually trans disposition, and
a fourth that shows couplings to the other three P atoms.
In the platinum complexes, the free P atom does not exhibit
coupling to 195Pt, the two mutually trans P atoms have cou-
plings in the range 2700–2850 Hz, and the P atom trans to
P
P
P
P
1
Pt
the organic ligand shows the smallest JPtP value (1700–
Pd
1800 Hz).
CH3
CH3
Cl
Cl
Complexes of the type [PtR2(DPPEPM-PP)] (1, 2) have
two uncoordinated P atoms that should be available to
coordinate a second metal center, thus permitting the for-
mation of heterobimetallic derivatives. Indeed, reaction
of 1 with [PtPh2(cod)] or [MCl2(cod)] (M = Pd, Pt), or of
2 with [PdCl2(cod)], does result in unsymmetrical species
as the major products 9–12 (although traces of symmetrical
species are always detected) (Scheme 2). In each case, these
complexes exhibit four high frequency resonances in their
31P NMR spectra, indicating that all four P atoms are
coordinated. In the case of [PtMe2(l-DPPEPM)PtPh2]
(9), all four signals have small JPtP values (1654–
1820 Hz), whereas in [PtMe2(l-DPPEPM)PtCl2] (10) there
are two smaller and two larger couplings.
The solid state structure of 10 has been reported previ-
ously [21]. Here we report the structure of its palladium
analogue [PtMe2(l-DPPEPM)PdCl2] (11). Its molecular
structure is shown in Fig. 3, and selected bond distances
and angles are presented in Table 3. The PtMe2 and PdCl2
units are disordered over both sites, but this has been mod-
eled successfully using partial occupancies (see Section 4).
Fig. 3. Molecular structure of 11, with atoms represented by thermal
ellipsoids at the 50% level. Hydrogen atoms have been omitted for clarity.
Table 3
˚
Selected bond distances (A) and angles (°) for 11
Pt–C(1)
Pt–P(3)
Pd–Cl(1)
Pd–P(1)
2.1993(13)
2.2797(10)
2.3381(11)
2.2177(9)
Pt–C(2)
Pt–P(4)
Pd–Cl(2)
Pd–P(2)
2.3327(12)
2.2234(10)
2.231(2)
2.2849(9)
C(1)–Pt–C(2)
C(1)–Pt–P(4)
C(2)–Pt–P(4)
Cl(1)–Pd–Cl(2)
Cl(1)–Pd–P(2)
Cl(2)–Pd–P(2)
P(2)–C(13)–P(3)
90.12(5)
90.77(4)
178.96(4)
88.58(7)
94.55(4)
175.98(6)
120.60(19)
C(1)–Pt–P(3)
C(2)–Pt–P(3)
P(3)–Pt–P(4)
Cl(1)–Pd–P(1)
Cl(2)–Pd–P(1)
P(1)–Pd–P(2)
176.49(4)
1
93.23(4)
85.89(4)
173.68(4)
91.37(7)
85.79(3)
The structure consists of two approximately square planar
units (the sums of the angles are Pt and Pd are 360.0° and
360.3°, respectively), rotated away from each other around

P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
533
Table 4
the flexible PCH2P bridge, giving a Pt–Pd distance of
6.35 A. The P–C–P angle of 120.6(19)° is similar to that
in the diplatinum complex, and larger than the analogous
angle in 1a. It is likely that the angle increases in order to
accommodate the presence of two metal centers.
˚
Selected bond distances (A) and angles (°) for 14
˚
Pt–Cl(1)
Pt–P(1)
Pd–Cl(2)
Pd–P(3)
2.3612(17)
2.2165(18)
2.3586(19)
2.2286(18)
Pt–C(6)
Pt–P(2)
Pd–Cl(3)
Pd–P(4)
2.101(6)
2.2972(16)
2.368(2)
2.227(2)
When [PtClR(cod)] (R = Me, Ph) is allowed to react
with DPPEPM, ionic complexes 6 and 7 are formed (vide
supra), which contain one free P atom, that we considered
might be available for further coordination. When
[PtCl2(cod)] or [PdCl2(cod)] is added, displacement of
cyclooctadiene does take place, but cleavage of one of the
Pt–P bonds occurs and the free chloride becomes coordi-
nated to give [PtClR(l-DPPEPM)MCl2] (13, M = Pt,
R = Me; 14, M = Pd, R = Ph) (Eq. (1)). The products have
been characterized by NMR spectroscopy and, in the case
of the phenyl complex, by high-resolution mass spectrom-
etry and X-ray crystallography.
Cl(1)–Pt–C(6)
Cl(1)–Pt–P(2)
C(6)–Pt–P(2)
Cl(2)–Pd–Cl(3)
Cl(2)–Pd–P(4)
Cl(3)–Pd–P(4)
P(2)–C(3)–P(3)
87.97(18)
93.05(6)
177.2(2)
93.11(8)
174.48(7)
91.71(8)
124.1(4)
Cl(1)–Pt–P(1)
C(6)–Pt–P(1)
P(1)–Pt–P(2)
Cl(2)–Pd–P(3)
Cl(3)–Pd–P(3)
P(3)–Pd–P(4)
178.27(6)
93.68(18)
85.32(6)
89.56(7)
176.80(8)
85.71(7)
In 3 and 4, one diphosphine unit of each ligand is coordi-
nated, leaving two diphosphine moieties available for further
bonding. This presents the possibility of forming trimetallic
derivatives. Thus, reaction of [MCl2(cod)] with DPPEPM,
followed by [PtR2(cod)] (R = Me, Ph), leads to trimetallic
complexes of the form [{PtR2(l-DPPEPM)}2M][MCl4]
(15, M = Pt, R = Me; 16, M = Pd, R = Me; 17, M = Pd,
R = Ph) (Eq. (2)). Again, the cations have been identified
by NMR spectroscopy and high resolution mass spectrome-
try, whereas the anions are postulated as PtCl24ꢁ or PdCl42ꢁ
based on the reaction stoichiometry. In each case the 31P
NMR spectrum contains four resonances. The mixed metal
P
P
P
P
P
P
P
P
+
+
Pt
Pt
-
PdCl2(cod)
Pd
Cl
R
Cl
Cl
R
Cl
6,7
13,14
ð1Þ
The molecular structure of 14 is displayed in Fig. 4, and se-
lected bond distances and angles are given in Table 4. This
structure is not disordered over the metal-containing sites.
It consists of two metal square planes (the sums of the an-
gles are 360.0 for Pt and 360.1 for Pd) rotated away from
1
complexes exhibit two signals with JPtP values around
1700 Hz, due to the P atoms attached to platinum, and two
signals with no satellites. In 15, there are two resonances with
couplings of ca 1800 Hz, due to the P atoms lying trans to
methyl groups, and signals at 30.3 (1JPtP = 2375 Hz) and
43.1 ppm (1JPtP = 2693 Hz), due to the P atoms coordinated
to the central platinum. The resonance with the larger cou-
pling is assigned to the terminal P atoms, because they are
Ph2PR moieties, and the other to the internal PhPR2 units.
It has not proved possible to isolate these complexes in pure
form, but each of the trimetallic cations has been character-
ized by its high resolution mass spectrum. A cluster of peaks
corresponding to the cation itself is observed and, in addi-
tion, a set of peaks due to the cation plus a chlorine atom
is found. The latter must involve abstraction of Cl from the
anion.
˚
each other to give a Pt–Pd distance of 6.20 A. The Pt–P dis-
˚
tances differ by 0.08 A, the longer bond involving the inter-
nal P atom that lies trans to the phenyl group [30]. In
contrast, the Pd–P distances are identical to each other,
as are the Pd–Cl distances. The P–C–P angle is 124.1(4)°,
larger than those found in 10 and 11.
P
P
P
P
P
2 +
P
P
P
P
P
+
PtR (cod)
2
2
R
P
R
2
M
Pt
M
Pt
R
R
P
P
P
P
P
15-17
3,4
ð2Þ
3. Summary
P
P
P
P
Careful addition of the appropriate metal complex to
the tetradentate ligand DPPEPM leads to complexes of
the form [PtR2(DPPEPM-PP)] (1, 2), [M(DPPEPM-PP)2]-
[MCl4] (3, 4) or [MR(DPPEPM-PPP)]Cl (6–8). Each of
these has uncoordinated P atoms that can be utilized in
Pt
Pd
Cl
Ph
Cl
Cl
Fig. 4. Molecular structure of 14, with atoms represented by thermal
ellipsoids at the 50% level. Hydrogen atoms have been omitted for clarity.

534
P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
the formation of bi- or trimetallic derivatives. Thus, the
free P atom(s) in 1 or 2, or in 6–8, may be used to generate
heterobimetallic species, whereas the two pairs of free P
atoms in 3 or 4 allow formation of trimetallic complexes
of the type [{PtR2(l-DPPEPM)}2M][MCl4] (15–17).
sulfur (0.001 g, 0.0038 mmol) was added, and a yellow solu-
2
tion formed. 31P{1H} NMR: dP 41.4 (d, JPP = 10 Hz,
2
1
1JPtP = 1825 Hz), 49.6 (d, JPP = 10 Hz, JPtP = 1829 Hz),
44.7 (br, 2P). 1H NMR: dH 0.15 (dd, JPH = 8 Hz,
3
2JPtH = 70 Hz, CH3), 0.34 (dd, 3JPH = 7 Hz, 2JPtH = 71 Hz,
CH3), 1.9–2.9 (several m, PCH2CH2P), 3.6–3.8 (br m,
PCH2P), 6.8–7.8 (m, C6H5).
4. Experimental section
All reactions were carried out under an atmosphere of
argon. Solvents were distilled prior to use. [PtCl2(cod)],
[PdCl2(cod)], [PtR2(cod)] (R = Me, Ph), [PtClR(cod)]
(R = Me, Ph), and [PdClMe(cod)] were prepared as re-
4.4. Synthesis of [Pd(DPPEPM-PP)2]PdCl4 (3)
A solution of [PdCl2(cod)] (0.013 g, 0.045 mmol) in ace-
tone (3.0 mL) was added dropwise to a suspension of
DPPEPM (0.030 g, 0.045 mmol) in acetone (0.8 mL) with
constant stirring. The solution darkened and it was allowed
to stir for another 10 min, and the solvent was evaporated.
The residue was washed several times with pentane and
precipitated from acetone/pentane to give the product as
a yellow powder (0.028 g, 75%). 31P{1H} NMR (acetone-
1
ported previously [22,31–34]. H and 31P{1H} NMR spec-
tra were recorded on a Bruker ARX-500 or Avance 300, or
a Varian Unity plus 300 spectrometer. High-resolution
mass spectra (HRMS) were obtained in FAB mode, on a
JEOL M Station-JMS700, using nitrobenzyl alcohol
(NBA) as solvent.
3
2
d6): dP ꢁ26.9 (ddd, JPP = 32 Hz, JPP = 4JPP = 16 Hz),
–12.6 (d, 3JPP = 32 Hz), 47.4 (5-line pattern, 2JPP = 16 Hz),
57.3 (apparent t, 2JPP = 16 Hz). 1H NMR (acetone-d6): dH
0.86 (m, 1 H, PCH2P), 1.2–2.8 (several m, PCH2CH2P),
4.1. Synthesis of [PtMe2(DPPEPM-PP)] (1)
An acetone solution (3.0 mL) of [PtMe2(cod)] (0.015 g,
0.045 mmol) was added dropwise, with constant stirring,
to a suspension of DPPEPM (0.030 g, 0.045 mmol) in ace-
tone (0.8 mL). The almost colorless solution was allowed to
stir for another 10 min, then the solvent was removed un-
der reduced pressure. The residue was washed several times
with pentane and precipitated from acetone/pentane as an
off-white powder (0.021 g, 53%). 31P{1H} NMR (acetone-
2
4.31 (d, JHH = 16 Hz, 1H, PCH2P), 6.8–8.3 (m, C6H5).
2
1H{31P} NMR (acetone-d6): dH 0.86 (d, JHH = 16 Hz,
1H, PCH2P), 1.3–2.6 (several m, PCH2CH2P), 4.32 (d,
2JHH = 16 Hz, 1H, PCH2P), 6.8–8.3 (m, C6H5).
4.5. Synthesis of [Pt(DPPEPM-PP)2]PtCl4 (4)
2
3
d6): dP ꢁ28.7 (dd, JPP = 68 Hz, JPP = 31 Hz), ꢁ12.4 (d,
This complex was prepared analogously and isolated as
an off-white powder in 70% yield. 31P{1H} NMR (acetone-
2
3
3JPP = 31 Hz), 42.0 (dd, JPP = 68 Hz, JPP = 4 Hz,
1JPtP = 1814 Hz), 49.4 (d, JPP = 4 Hz, JPtP = 1829 Hz).
d6): dP ꢁ27.7 (ddd, JPP = 32 Hz, JPP = 4JPP = 18 Hz),
3
1
3
2
1H NMR (acetone-d6): dH 0.41 (dd, JPH = 7 Hz,
ꢁ12.7 (d, JPP = 32 Hz), 34.3 (5-line pattern, JPP = 18 Hz,
3
3
2JPtH = 63 Hz, CH3), 0.47 (dd, 3JPH = 7 Hz, 2JPtH = 63 Hz,
1JPtP = 2370 Hz), 44.7 (apparent t, 2JPP = 18 Hz,
1JPtP = 2665 Hz). 1H NMR (acetone-d6): dH 0.87 (m,
1 H, PCH2P), 1.2–2.7 (several m, PCH2CH2P), 4.55 (d,
CH3), 1.9–3.1 (several m, PCH2CH2P, PCH2P), 7.0–7.5 (m,
12
C6H5). HRMS: calc. for C42H43P4195Pt+ (M ꢁ CH3)+,
866.1963; observed, 866.2022; calc. for C42H43OP4195Pt+
12
2JHH = 16 Hz, 1H, PCH2P), 6.9–8.1 (m, C6H5). H{31P}
1
2
(MO ꢁ CH3), 882.1912; observed, 882.1905. Crystals of
[PtMe2{DPPEPM(O)2-PP}] (1a) were obtained from
CDCl3 solution.
NMR (acetone-d6): dH 0.87 (d, JHH = 16 Hz, 1H,
PCH2P), 1.2–2.8, (several m, PCH2CH2P), 4.32 (d,
2JHH = 16 Hz, 1H, PCH2P), 6.9–8.1 (m, C6H5). HRMS:
calc. for C82H81P8195Pt+ (MH+), 1508.3887; observed,
12
4.2. Synthesis of [PtPh2(DPPEPM-PP)] (2)
1508.3933. Crystals, which proved to be [Pt2(l-Cl)
(l-DPPEPM)2]Cl3 (5), were obtained by slow evaporation
of a CDCl3 solution.
This complex was prepared similarly from [PtPh2(cod)]
(0.020 g, 0.045 mmol) and DPPEPM (0.030 g, 0.045 mmol)
and isolated as a pale yellow powder (0.026 g, 57%).
4.6. Synthesis of [PtMe(DPPEPM-PPP)]Cl (6)
2
31P{1H} NMR (acetone-d6): dP ꢁ28.0 (dd, JPP = 74 Hz,
3
3
3JPP = 30 Hz, JPtP = 62 Hz), ꢁ12.8 (d, JPP = 30 Hz),
A solution of [PtClMe(cod)] (0.016 g, 0.045 mmol) in
acetone (3.0 mL) was added dropwise to a suspension of
DPPEPM (0.030 g, 0.045 mmol) in acetone (0.8 mL). A
colorless solution formed, which was allowed to stir for
another 10 min. The solvent was removed under vacuum,
and the residue was washed with pentane, then dissolved
in acetone. Addition of pentane gave the product as a white
powder (0.027 g, 85%). 31P{1H} NMR (acetone-d6): dP
2
1
1
37.9 (d, JPP = 74 Hz, JPtP = 1723 Hz), 41.6 (s, JPtP
= 1733 Hz).
4.3. Synthesis of [PtMe2(l-DPPEPM(S)2-PP)] (1b)
An acetone-d6 solution (1.0 mL) of [PtMe2(cod)] (0.005 g,
0.015 mmol) was added dropwise, with constant shaking, to
a suspension of DPPEPM (0.010 g, 0.015 mmol) in acetone-
d6 (0.2 mL) in an NMR tube. To this solution elemental
2
3
2
ꢁ19.5 (dd, JPP = 24, JPP = 9 Hz), 28.9 (ddd, JPP = 384,
3
1
2
19, J PP = 9 Hz, JPtP = 2833 Hz), 43.7 (ddd, JPP = 24,

P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
535
1
2
19, 5 Hz, JPtP = 1785 Hz), 54.8 (dd, JPP = 384, 5 Hz,
1JPtP = 2718 Hz). 1H NMR (acetone-d6): dH 0.34 (q,
4.10. Synthesis of [PtMe2(l-DPPEPM)PtCl2] (10)
3JPH = 6 Hz, JPtH = 30 Hz, CH3), 1.4–1.5, 2.3–2.9, 3.2–
A solution of [PtMe2(cod)] (0.015 g, 0.045 mmol) in ace-
tone (3.0 mL) was added dropwise to a suspension of
DPPEPM (0.030 g, 0.045 mmol) in acetone (0.8 mL). To
the resulting nearly colorless solution was added
[PtCl2(cod)] (0.017 g, 0.045 mmol), and the solution was al-
lowed to stir for another 10 min. The solvent was removed
under vacuum, and the residue was washed several times
with pentane and isolated from acetone/pentane as a yel-
low powder (0.027 g, 52%). 31P{1H} NMR (acetone-d6):
2
3.4 (m, PCH2CH2P), 3.89–3.93, 4.08–4.20 (m, PCH2P)
7.2–8.0 (m, C6H5). HRMS: calc. for C42H43P4195Pt+
12
(M+), 866.1963; observed, 866.1987. A cluster of peaks
around m/z 882 due to [PtMe{DPPEPM(O)-PPP}]+ was
also observed.
4.7. Synthesis of [PtPh(DPPEPM-PPP)]Cl (7)
1
1
A solution of [PtClPh(cod)] (0.006 g, 0.015 mmol) in
acetone-d6 (0.8 mL) was added dropwise to a suspension
of DPPEPM (0.010 g, 0.015 mmol) in acetone-d6 (0.3 mL)
to give a colorless solution. 31P{1H} NMR: dP ꢁ20.4
dP 36.4 (s, JPtP = 3535 Hz), 39.2 (s, JPtP = 1743 Hz),
1
1
41.5 (s, JPtP = 3648 Hz), 48.5 (s, JPtP = 1786 Hz).
4.11. Synthesis of [PtMe2(l-DPPEPM)PdCl2] (11)
2
3
2
(dd, JPP = 24, JPP = 6 Hz), 23.3 (ddd, JPP = 375, 19,
3JPP = 6 Hz, JPtP = 2834 Hz), 39.6 (ddd, JPP = 24, 19,
1
2
This complex was prepared similarly and obtained as a
yellow powder in 60% yield. 31P{1H} NMR (acetone-d6):
dP 40.3 (s, 1JPtP = 1740 Hz), 48.9 (s, 1JPtP = 1795 Hz), 61.0
1
2
6 Hz, JPtP = 1733 Hz), 47.8 (dd, JPP = 375, 6 Hz,
1JPtP = 2721 Hz).
12
(s), 64.8 (s). HRMS: calc.. for C43H46P4 106Pd195Pt35Cl+
4.8. Synthesis of [PdMe(DPPEPM-PPP)]Cl (8)
(M ꢁ Cl)+, 1022.0921; observed, 1022.0896. Crystals of
[PtMe2(l-DPPEPM)PdCl2] suitable for an X-ray diffraction
study were grown by slow evaporation of an acetone-d6
solution.
An acetone-d6 solution (1.0 mL) of [PdClMe(cod)]
(0.004 g, 0.015 mmol) was added dropwise to a suspension
of DPPEPM (0.010 g, 0.015 mmol) in acetone-d6 (0.2 mL)
to give a pale yellow solution. 31P{1H} NMR: dP ꢁ17.0
4.12. Synthesis of [PtPh2(l-DPPEPM)PdCl2] (12)
2
3
2
(dd, JPP = 26 Hz, JPP = 11 Hz), 31.3 (ddd, JPP = 374,
3
2
37 Hz, JPP = 11 Hz), 39.3 (ddd, JPP = 37, 26, 26 Hz),
This complex was prepared similarly from [PtPh2(cod)]
and DPPEPM, followed by addition of [PtCl2(cod)], and
isolated as a yellow solid in 55% yield. 31P{1H} NMR (ace-
2
56.0 (dd, JPP = 374, 26 Hz). 1H NMR: dH 0.38 (q,
3JPH = 6 Hz, CH3), 1.3–2.5 (several m, PCH2CH2P),
3.01–3.05, 4.68–4.72 (m, PCH2P), 7.0–7.7 (m, C6H5). In
addition, signals were detected in the 31P{1H} NMR spec-
trum for [PdMe{DPPEPM(O)-PPP}]Cl: dP 28.5 (ddd,
1
1
tone-d6): dP 33.7 (s, JPtP = 1650 Hz), 40.2 (s, JPtP
=
1727 Hz), 64.1 (s), 64.3 (s). 1H NMR (acetone-d6): 1.0–
3.0 (several m, PCH2CH2P), 3.3–3.8 (br m, PCH2P), 6.7–
8.3 (m, C6H5).
2JPP = 374, 38 Hz, JPP = 16 Hz), 34.5 (d, JPP = 16 Hz),
3
2
2
2
35.6 (dd, JPP = 38, 26 Hz), 56.3 (dd, JPP = 374, 26 Hz).
4.13. Synthesis of [PtClMe(l-DPPEPM)PtCl2] (13)
4.9. Synthesis of [PtMe2(l-DPPEPM)PtPh2] (9)
A solution of [PtClMe(cod)] (0.005 g, 0.015 mmol) in
acetone (0.8 mL) was added dropwise to a suspension of
DPPEPM (0.010 g, 0.015 mmol) in acetone (0.3 mL). To
the resulting colorless solution was added [PtCl2(cod)]
(0.005 g, 0.015 mmol). The solvent was removed and the
residue was washed with pentane and dried in vacuo.
An acetone solution (3.0 mL) of [PtMe2(cod)] (0.015 g,
0.045 mmol) was added dropwise, with constant stirring,
to a suspension of DPPEPM (0.030 g, 0.045 mmol) in ace-
tone (0.8 mL). An almost colorless solution formed. Solid
[PtPh2(cod)] (0.020 g, 0.045 mmol) was added slowly and
the mixture was allowed to stir for a further 10 min before
the solvent was removed. The residue was washed several
times with pentane and dissolved in acetone. Addition of
pentane resulted in precipitation of the product as a pale
yellow powder (0.022 g, 47%). 31P{1H} NMR (acetone-
2
31P{1H} NMR (acetone-d6): dP 39.5 (d, JPP = 18 Hz,
1
1JPtP = 3581 Hz), 39.7 (s, JPtP = 3654 Hz), 41.2 (s,
2
1
1JPtP = 4256 Hz), 41.4 (d, JPP = 18 Hz, JPtP = 1688 Hz).
4.14. Synthesis of [PtClPh(l-DPPEPM)PdCl2] (14)
2
1
d6): dP 32.3 (d, JPP = 6 Hz, JPtP = 1654 Hz), 40.5 (d,
2JPP = 6 Hz, JPtP = 1734 Hz), 40.6 (d, JPP = 7 Hz,
1
2
This complex was prepared analogously from [PtClPh
(cod)], DPPEPM and [PdCl2(cod)], and isolated as a pale
1JPtP = 1820 Hz), 48.8 (d, JPP = 7 Hz, JPtP = 1811 Hz).
2
1
1H NMR (acetone-d6): dH 0.40 (dd, JPH = 7 Hz,
3
yellow solid. 31P{1H} NMR (acetone-d6): dP 36.4 (s, 1JPtP
=
2JPtH = 66 Hz, CH3), 0.47 (dd, 3JPH = 7 Hz, 2JPtH = 66 Hz,
4258 Hz), 37.3 (d, 2J PP = 24 Hz, 1JPtP = 1605 Hz), 62.4 (dd,
2JPP = 24, 10 Hz), 64.3 (d, 2JPP = 10 Hz). HRMS: calc.. for
CH3), 1.0–3.4 (several m, PCH2CH2P, PCH2P), 6.4–7.8 (m,
þ
þ
+
C6H5). HRMS: calc. for C42H43P4195Pt2 (M ꢁ CH3,
12
12
C H45P4106Pd195Pt35Cl2 (M ꢁ Cl ), 1104.0531; observed,
47
2C6H5)+, 1061.1611; observed, 1061.1636.
1104.0524. Crystals of [PtPhCl(l-DPPEPM)PdCl2] suitable

536
P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
for an X-ray diffraction study were grown by slow evapora-
tion of an acetone-d6 solution.
NMR (acetone-d6): dH 0.23 (dd, 3JPH = 7 Hz,
2JPtH = 70 Hz, CH3), 0.36 (dd, 3JPH = 8 Hz, 2JPtH = 71 Hz,
CH3), 1.3–2.8 (several m, PCH2CH2P), 3.34–3.39, 5.02–5.07
(m, PCH2P), 6.6–7.7 (m, C6H5). 1H{31P} NMR (acetone-d6):
4.15. Synthesis of [{PtMe2(l-DPPEPM)}2Pt][PtCl4]
(15)
2
2
dH 0.23 (s, JPtH = 70 Hz, CH3), 0.36 (s, JPtH = 71 Hz,
2
CH3), 1.3–2.8 (several m, PCH2CH2P), 3.34 (d, JHH
=
2
An acetone solution (3.0 mL) of [PtCl2(cod)] (0.017 g,
0.045 mmol) was added dropwise to a suspension of
DPPEPM (0.030 g, 0.045 mmol) in acetone (0.8 mL).
[PtMe2(cod)] (0.015 g, 0.045 mmol) was added and the mix-
ture was allowed to stir for another 10 min, and the solvent
was removed. The residue was washed several times with
pentane and the product was isolated from acetone/pen-
tane as a colorless powder (0.035 g, 68%). 31P{1H} NMR
15 Hz, 1H, PCH2P), 5.02 (d, JHH = 15 Hz, 1H, PCH2P),
þ
6.6–7.7 (m, C6H5). HRMS: calc. for C86H93P8106Pd195Pt2
12
(MH+), 1869.3509; observed, 1869.3434. A cluster of peaks
around m/z 1904 due to (M + Cl)+ was also observed.
4.17. Synthesis of [{PtPh2(l-DPPEPM)}2Pd][PdCl4]
(17)
2
1
(acetone-d6): d P 30.3 (apparent t, JPP = 16 Hz, JPtP
=
This complex was prepared analogously from [PdCl2
(cod)] and DPPEPM, followed by [PtPh2(cod)], and ob-
tained as a yellow solid in 65% yield. 31P{1H} NMR
2
1
2375 Hz), 40.2 (d, JPP = 9 Hz, JPtP = 1790 Hz), 43.1
2
1
(apparent t, JPP = 16 Hz, JPtP = 2693 Hz), 49.7 (d,
2JPP = 9 Hz, JPtP = 1791 Hz). H NMR (acetone-d6): dH
(acetone-d6): dP 33.9 (d, JPP = 7 Hz, JPtP = 1654 Hz),
1
1
2
1
3
2
2
2
1
0.17 (dd, JPH = 7 Hz, JPtH = 70 Hz, CH3), 0.35 (dd,
43.3 (t, JPP = 15 Hz), 44.1 (d, JPP = 7 Hz, JPtP =
3JPH = 7 Hz, JPtH = 71 Hz, CH3), 1.1–2.7 (several m,
1703 Hz), 54.8 (t, JPP = 15 Hz). 1H NMR (acetone-d6):
2
2
PCH2CH2P), 3.10–3.14, 5.22–5.27 (m, PCH2P), 6.7–7.7
dH 1.3–2.4 (several m, PCH2CH2P), 3.62–3.73, 4.95–5.01
(m, C6H5). HRMS: calc. for C86H93P8195Pt3 (MH+),
(m, PCH2P), 6.3–8.6 (m, C6H5). HRMS: calc.. for
þ
12
H100P8106Pd195Pt235Cl+ (M + Cl)+, 2151.3745; ob-
12
1958.4122; observed, 1958.3901. A cluster of peaks around
C
106
m/z 1992 due to (M + Cl)+ was also observed.
served, 2151.3738.
4.16. Synthesis of [{PtMe2(l-DPPEPM)}2Pd][PdCl4]
(16)
4.18. X-ray crystallography
Crystals of appropriate dimensions were mounted on
glass fibers in random orientations. Preliminary examination
and data collection were performed using a Bruker SMART
Charge Coupled Device (CCD) Detector system single
crystal X-ray diffractometer using graphite monochromated
This complex was prepared analogously from [PdCl2
(cod)] and DPPEPM, followed by [PtMe2(cod)], and ob-
tained as a yellow solid in 70% yield. 31P{1H} NMR
2
1
(acetone-d6): dP 41.1 (apparent t, JPP = 8 Hz, JPtP
1756 Hz), 43.5 (unresolved m), 49.4 (d, JPP = 8 Hz,
=
2
˚
Mo Ka radiation (k = 0.71073 A) equipped with a sealed
tube X-ray source. Preliminary unit cell constants were
2
1JPtP = 1789 Hz), 56.0 (apparent t, JPP = 15 Hz). 1H
Table 5
Crystallographic data for 1a, 5, 11 and 14
1a
5
11
14
Crystal system
Monoclinic
P21/c, 4
13.188(3)
15.424(2)
19.507(4)
90
96.447(18)
90
3942.7(13)
1.539
Monoclinic
P21/n, 4
14.278(3)
21.400(4)
29.452(6)
90
98.372(13)
90
8 903(3)
1.578
Triclinic
Triclinic
ꢀ
ꢀ
Space group, Z
P1, 2
P1, 2
˚
a (A)
12.3272(3)
13.7559(4)
13.9446(4)
104.613(2)
101.693(2)
99.907(2)
2177.60(10)
1.648
13.1936(4)
14.0729(5)
15.9353(5)
114.430(2)
109.842(2)
91.432(3)
2486.22(14)
1.602
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
Cell volume (A )
Dcalc (Mg/m3)
3
˚
Temperature (K)
Absorption coefficient (mmꢁ1
160(2)
3.757
120(2)
3.463
218(2)
3.922
140(2)
3.497
)
h Range (°)
No. of reflections collected
No. of independent reflections
Abs. corr.
1.69–27.00
74333
8602
Semi-empirical
from equivalents
451
0.0749, 0.1013
0.1087, 0.1092
1.167
1.69–26.00
117885
17491
1.74–29.00
47545
11218
Semi-empirical
from equivalents
489
0.0345, 0.0829
0.0514, 0.0893
1.038
2.15–28.00
55566
11864
Semi-empirical
from equivalents
581
0.0489, 0.1104
0.0957, 0.1264
1.043
Empirical
No. of parameters refined
R(F), Rw(F2) (F2 > 2.0r(F2))
R(F), Rw(F2) (all data)
Goodness of fit on F2
1012
0.0569, 0.0992
0.1405, 0.1222
0.990
1.118, ꢁ1.008
ꢁ3
˚
Largest difference peak and hole (e A
)
1.322, ꢁ2.898
1.154, ꢁ1.011
1.904, ꢁ1.811

P. Nair et al. / Journal of Organometallic Chemistry 691 (2006) 529–537
537
determined with a set of 45 narrow frames (0.3° in -) scans.
Appendix A. Supplementary data
Typical data sets consisted of 3636 frames of intensity data
collected with a frame width of 0.3° in - and counting time
of 15–30 s/frame at a crystal to detector distance of
4.950 cm. The double pass method of scanning was used to
exclude any noise. The collected frames were integrated
using an orientation matrix determined from the narrow
frame scans. SMART and SAINT software packages (Bruker
Analytical X-ray, Madison, WI, 2003) were used for data
collection and data integration. Analysis of the integrated
data did not show any decay. Final cell constants were deter-
mined by global refinement of xyz centroids of thresholded
reflections from the complete data set. Collected data were
corrected for systematic errors using SADABS (Sheldrick, G.
M., Bruker Analytical X-ray, Madison, WI, 2003) based
on the Laue symmetry using equivalent reflections.
Supplementary data associated with this article can be
found, in the online version, at doi:10.1016/j.jorganchem.
2005.09.021.
References
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Crystal data and intensity data collection parameters are
listed in Table 5. Structure solution and refinement were
carried out using the SHELXTL-PLUS software package
(Sheldrick, G. M., Bruker Analytical X-ray Division, Mad-
ison, WI, 2002). The structures were solved by direct meth-
ꢀ
ods and refined successfully in the space groups, P1, P21/n,
ꢀ
P1 and P21/c, respectively. Full matrix least-squares refine-
P
2
ment was carried out by minimizing
wðF 2o ꢁ F 2cÞ . The
non-hydrogen atoms were refined anisotropically to con-
vergence. The final residual values and structure refinement
parameters are listed in Table 5.
Both the triclinic structures (11 and 14) show disorder
and they contain solvent molecules in the lattice. The disor-
der could be resolved in both cases. In the case of 11, the Pt
and Pd atoms, and the ligands attached to them (Me and
Cl), are disordered over both sites. This disorder was mod-
eled using partial occupancies. The acetone solvate is disor-
dered due to the presence of an inversion center. Again the
disorder was resolved by using partial occupancy for the
disordered atoms. One of the phenyl groups attached to
the P atom is disordered in case of 14. The two disordered
C-atoms of the phenyl group were modeled over two sites
with partial occupancies. The solvent acetone exhibits the
same type of disorder as in the previous structure.
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic Data
Centre CCDC Nos. 283864–283867 for 1a, 11, 14, and 5,
respectively. Copies of this information may be obtained free
of charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK [fax (int code) +44 (1223) 336
033, or deposit@ccdc.cam.ac.uk or www: http://www.ccdc.
cam.ac.uk].
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Acknowledgments
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Thanks are expressed to the National Science Founda-
tion (Grant No. 9974801) and the University of Missouri
Research Board for instrumentation grants.