Mono- and di-nuclear palladium(II) complexes with bulky arsino(phosphino)methanes in different coordination modes

Article abstract of DOI:10.1039/b202879b

The peralkylated arsino(phosphino)methanes R₂AsCH₂PiPr₂ (R = tBu 2, iPr 3) react with trans-[PdCl₂(NCPh)₂]1 to give the chelate compounds [PdCl₂(κ²-R₂AsCH₂PiPr ₂)] 4, 5 which, via salt metathesis with KBr, KI (or NaI) and CF₃CO₂Ag, are converted to the dibromo-, diiodo-, and bis(trifluoracetato)-palladium(II) derivatives 6-11, respectively. Whereas from 2,3 and [{Pd(μ-Cl)(η³-C₃H₅)}₂] 12 the mono-cationic species [Pd(η³-C₃H₅)(κ²-R ₂-AsCH₂PiPr₂)]PF₆ 13, 14 are obtained, treatment of 4, 5 with AgPF₆ in acetonitrile affords the di-cationic complexes [Pd(NCCH₃)₂(κ²-R₂AsCH ₂PiPr₂)](PF₆)₂ 15,16. Compound 15 (R = tBu) reacts with Na(acac) to give [Pd(κ²-acac)-(κ²-R₂AsCH ₂PiPr₂)]PF₆ 17. The reaction of 4,5 with AgPF₆ in acetone leads to the formation of the di-nuclear complexes [{Pd(μ-Cl)(κ²-R₂AsCH₂PiPr ₂)}₂](PF₆)₂ 18, 19, which in the presence of SbiPr₃ or pyridine undergo bridge cleavage to yield the mono-nuclear chelate derivatives [PdCl(L)(κ²-R₂AsCH₂PiPr₂)] PF₆, mostly as a mixture of cis/trans isomers. The methylpalladium(II) compound [PdCl(CH₃)(κ₂-tBu₂AsCH₂ PiPr₂)] 25, prepared from [PdCl(CH₃)(η₄-C₈H₁₂)] 24 and 2, reacts with Na[B(Ar_F)₄] to afford the A-frame type complex [Pd₂(CH₃)₂(μ-Cl)-(μ-tBu₂ AsCH₂PiPr₂)₂][B(Ar_F)₄] 27. In contrast, the related precursor [PdCl(CH₃)(κ²-iPr₂AsCH₂ PiPr₂)], generated in situ from 24 and 3, gives, upon treatment with Na[B(Ar_F)₄], a mixture of two products 28a,b being the corresponding head-to-tail and head-to-head isomers. The mono-nuclear compounds 4 and 13 as well as the A-frame type complex 27 have been characterized by X-ray crystallography.

Full text of DOI:10.1039/b202879b

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Mono- and di-nuclear palladium(II) complexes with bulky
arsino(phosphino)methanes in different coordination modes
Ulrich Schmidt, Kerstin Ilg, Carsten D. Brandt and Helmut Werner*
Institut für Anorganische Chemie der Universität Würzburg, Am Hubland, D-97074 Würzburg,
Germany. E-mail: helmut.werner@mail.uni-wuerzburg.de
Received 21st March 2002, Accepted 2nd May 2002
First published as an Advance Article on the web 6th June 2002
The peralkylated arsino(phosphino)methanes R2AsCH2PiPr2 (R = tBu 2, iPr 3) react with trans-[PdCl2(NCPh)2] 1
to give the chelate compounds [PdCl2(κ2-R2AsCH2PiPr2)] 4, 5 which, via salt metathesis with KBr, KI (or NaI)
and CF3CO2Ag, are converted to the dibromo-, diiodo-, and bis(trifluoracetato)-palladium() derivatives 6–11,
respectively. Whereas from 2, 3 and [{Pd(µ-Cl)(η3-C3H5)}2] 12 the mono-cationic species [Pd(η3-C3H5)(κ2-R2-
AsCH2PiPr2)]PF6 13, 14 are obtained, treatment of 4, 5 with AgPF6 in acetonitrile affords the di-cationic complexes
[Pd(NCCH3)2(κ2-R2AsCH2PiPr2)](PF6)2 15, 16. Compound 15 (R = tBu) reacts with Na(acac) to give [Pd(κ2-acac)-
(κ2-R2AsCH2PiPr2)]PF6 17. The reaction of 4, 5 with AgPF6 in acetone leads to the formation of the di-nuclear
complexes [{Pd(µ-Cl)(κ2-R2AsCH2PiPr2)}2](PF6)2 18, 19, which in the presence of SbiPr3 or pyridine undergo
bridge cleavage to yield the mono-nuclear chelate derivatives [PdCl(L)(κ2-R2AsCH2PiPr2)]PF6, mostly as a mixture
of cis/trans isomers. The methylpalladium() compound [PdCl(CH3)(κ2-tBu2AsCH2PiPr2)] 25, prepared from
[PdCl(CH3)(η4-C8H12)] 24 and 2, reacts with Na[B(ArF)4] to afford the A-frame type complex [Pd2(CH3)2(µ-Cl)-
(µ-tBu2AsCH2PiPr2)2][B(ArF)4] 27. In contrast, the related precursor [PdCl(CH3)(κ2-iPr2AsCH2PiPr2)], generated
in situ from 24 and 3, gives, upon treatment with Na[B(ArF)4], a mixture of two products 28a,b being the
corresponding head-to-tail and head-to-head isomers. The mono-nuclear compounds 4 and 13 as well as the
A-frame type complex 27 have been characterized by X-ray crystallography.
In the context of our studies on the coordination chemistry
of unsymmetrical, possibly hemilabile, chelating systems such
as R2PCH2CH2OMe and R2AsCH2CH2OMe,1,2 we recently
reported the synthesis of the first representatives of arsino-
(phosphino)methanes R2AsCH2PRЈ2 with bulky alkyl or
cycloalkyl groups R and RЈ at the donor centres.3 We first tested
the bonding capabilities of these molecules towards rhodium()
and found that mono-nuclear as well as di-nuclear complexes
with either monodentate or bidentate R2AsCH2PRЈ2 ligands
can be obtained.3,4 As a continuation of this work, we turned
our interest to palladium(), being isoelectronic to rhodium(),
as the metal centre and describe in this article the preparation
of a series of neutral and cationic compounds, in which the
bulky arsino(phosphino)methanes coordinate either in a chelat-
ing or bridging mode. Some preliminary results have already
been communicated.5
Scheme 1
1H NMR spectra of the free ligands singlet resonances are
observed.
The result of the X-ray crystal structure analysis of 4 (poss-
essing Cs symmetry) is shown in Fig. 1. The coordination geom-
etry around the palladium() centre is distorted square-planar
with a Cl(1)–Pd–Cl(2) bond angle of 93.66(5)Њ. The As–Pd–P
bite angle of 74.94(3)Њ is quite small and comparable to the
P–Pd–P bite angle of the dppm relatives [PdCl2(κ2-Ph2PCH2-
PPh2)] [72.68(3)Њ]6 and [PdI2(κ2-Ph2PCH2PPh2)] (73.56Њ).7
The PdAsCP four-membered ring is not strictly planar, the
dihedral angle between the planes [As,C,P] and [As,Pd,P] being
10.9Њ.
Both chelate complexes 4 and 5 undergo salt metathesis
reactions in the presence of KBr and KI or NaI, respectively. In
acetone or acetone–CH2Cl2 as solvent, substitution products
6–9 are formed and isolated as yellow (6, 7), brown (8) or
orange (9) air-stable solids in good to excellent yields (see
Scheme 1). The chemical properties as well as the spectroscopic
data of 6–9 are quite similar to those of the chloro derivatives
and deserve no further comment.
Results and discussion
Mono-nuclear neutral and cationic chelate complexes with
R2AsCH2PiPr2 as ligands
Addition of a solution of trans-[PdCl2(NCPh)2] 1 in CH2Cl2 to
a solution containing an equimolar amount of tBu2AsCH2-
PiPr2 2 or iPr2AsCH2PiPr2 3 in CH2Cl2 affords the chelate com-
plexes 4 and 5 in, respectively, 75% and 83% yield (Scheme 1).
The red or red–brown air-stable compounds are readily soluble
in acetone and CH2Cl2, nearly insoluble in ether and pentane
and thermally stable up to about 185 ЊC. The most typical
1
features of the H and 13C NMR spectra of 4 and 5 are the
positions of the signals for the protons and carbon atoms of the
bridging CH2 groups of the ligands, which are significantly
shifted to lower field compared to the arsino(phosphino)-
methanes 2 and 3. Moreover, the signal for the AsCH2P
protons appears as a doublet with J(P,H) = 9.7 Hz, while in the
DOI: 10.1039/b202879b
J. Chem. Soc., Dalton Trans., 2002, 2815–2824
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Fig. 2 Selected data of NOE measurements (in CDCl3) for compound
13 (δ in ppm).
Fig. 1 Molecular structure of compound 4. Selected bond distances
(Å) and angles (Њ): Pd–As 2.3526(7), Pd–P 2.2427(13), Pd–Cl(1)
2.3595(14), Pd–Cl(2) 2.3657(13), As–C(1) 1.974(5), P–C(1) 1.840(5);
As–Pd–P 74.94(3), As–C(1)–P 94.3(2), Cl(1)–Pd–Cl(2) 93.66(5),
As–Pd–Cl(2) 170.24(4), P–Pd–Cl(1) 170.08(5), As–Pd–Cl(1) 95.23(4),
P–Pd–Cl(2) 96.25(5).
Chart 1 Assignment of protons and carbon atoms of the C3H5 ligand
in compounds 13 and 14, and of carbon atoms of the acac ligand in
compound 17.
and P atoms, the two isopropyl groups at phosphorus and the
two tert-butyl or isopropyl groups at arsenic are diastereotopic
The chloro ligands of 4 and 5 can also be replaced by tri-
fluoracetate but in this case it is necessary to use instead of
CF3CO2Na or CF3CO2K the corresponding silver salt. Treat-
ment of solutions of 4 or 5 in CH2Cl2 with solutions of
CF3CO2Ag in acetone at Ϫ40 ЊC affords, after warming to
room temperature and separation of AgCl, the bis(trifluor-
acetato) compounds 10 and 11 as pale-yellow moderately air-
sensitive solids in 56% and 90% yield, respectively. In CH2Cl2 or
acetone, both compounds 10 and 11 are not exceedingly stable
and decompose in 4–6 h to give palladium precipitates. Since in
nitromethane 10 and 11 possess a molar conductivity of ca. 25
cm2 ΩϪ1 molϪ1 (i.e., significantly less than anticipated for 1 : 1
electrolytes),8 we conclude that in polar solvents a partial dis-
sociation takes place. However, owing to the positions of the
asymmetric and symmetric OCO stretching vibrations in the IR
spectra (in Nujol) of 10 and 11 there is no doubt that in the
crystal the two CF3CO2 groups are covalently linked to the
metal in a monodentate bonding mode.
1
and thus give rise both in the H and 13C NMR spectra of 13
and 14 to two sets of signals.
To obtain information about the detailed structural aspects
of the cationic π-allyl complexes, an X-ray crystal structure
investigation of 13 was carried out. The molecular diagram
(Fig. 3) confirms the chelating coordination mode of the
The π-allylpalladium complexes 13 and 14 (Scheme 2)
Scheme 2
containing 2 and 3 as chelating ligands were prepared from
[{Pd(µ-Cl)(η3-C3H5)}2] 12 following the procedure used for
analogous compounds with P,N-donor groups.9 After recrystal-
lization from ethyl acetate, the PF6 salts 13 and 14 were
obtained as white solids revealing in nitromethane a molar
conductivity typical for 1 : 1 electrolytes.8 The 1H NMR spectra
of 13 and 14 display five well-separated signals for the allylic
protons indicating that at least at room temperature a η3-η1-η3
rearrangement of the C3H5 ligand does not take place. The
assignment for these signals is based on NOE measurements
(Fig. 2) as well as in the case of 13 on a C,H correlation spec-
trum in CDCl3. From the latter it is obvious that the resonance
for the carbon atom C1 of the allylic ligand (for numbering see
Chart 1 in the Experimental section) at δ 66.4 correlates with
the signals of the protons H1s and H1a and the resonance for C3
at δ 63.7 with the signals of H3s and H3a, respectively. Since
there is no mirror plane passing through the coordinated As
Fig. 3 Molecular structure of compound 13 (PF6 counterion omitted
for clarity). Selected bond distances (Å) and angles (Њ): Pd–As
2.4063(6), Pd–P(1) 2.3079(12), Pd–C(1) 2.169(3), Pd–C(2) 2.162(4), Pd–
C(3) 2.197(4), As–C(4) 1.973(3), P(1)–C(4) 1.848(3), C(1)–C(2)
1.371(7), C(2)–C(3) 1.361(7); As–Pd–P(1) 74.81(2), As–C(4)–P(1)
97.09(14), C(4)–As–Pd 90.70(9), C(4)–P(1)–Pd 97.11(10), C(3)–C(2)–
C(1) 123.7(4).
arsino(phosphino)methane with bond lengths Pd–P and Pd–As
that are ca. 0.06 Å longer than in 4. The distance Pd–C(1) is
somewhat shorter (by 0.03 Å) than the distance Pd–C(3), prob-
ably due to the stronger trans influence of phosphines com-
pared with arsines. Despite the positive charge of 13, the
As–Pd–P bite angle of 74.81Њ is almost identical to that of the
neutral compound 4. The plane of the allylic carbon atoms
C(1)–C(3) is not exactly perpendicular to the plane containing
the palladium, arsenic and phosphorus atoms, the dihedral
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J. Chem. Soc., Dalton Trans., 2002, 2815–2824

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angle between the two planes being 116.1Њ with the carbon atom
C2 pointing away from the metal centre.
The reactions of 4 and 5 with two equivalents of AgPF6 in
acetonitrile at Ϫ30 ЊC afford the dicationic complexes 15 and 16
which were isolated as yellow solids in 83% (15) and 47% (16)
yields (Scheme 3). Both the elemental analysis and conductivity
Scheme 4
phosphorus atom at δ Ϫ12.1 (18) and Ϫ4.7 (19) which is exactly
4 ppm downfield compared with the monomeric di-cations
15 and 16.
Scheme 3
measurements are in agreement with the proposed com-
position. Similarly to the starting material 1, the nitrile ligands
can easily be displaced by other nucleophiles and thus upon
treatment of 15 with Na(acac) the mono-cationic species 17 is
formed. Since the Pd(acac) unit is connected to an unsym-
metrical chelating moiety, the 1H NMR spectrum of 17 exhibits
two signals for the methyl protons of the acetylacetonate
and the 13C NMR spectrum two resonances, separated only
by 0.4 ppm, for the carbonyl carbon atoms of the acac ligand.
The 13C–31P coupling constant of the signal for the 13C carbon
nuclei trans to phosphorus is rather small (1.9 Hz) and compar-
able to the value found for [Pd(κ2-acac)(κ2-Ph2PCH2PPh2)]PF6
(1.5 Hz).10
In order to test the potential utility of the cations [Pd-
(NCCH3)2(κ2-R2AsCH2PiPr2)]2ϩ as pre-catalysts for the gener-
ation of polyketones, a solution of 15 (10 mg) in methanol
(10 cm3) was treated in an autoclave with CO and ethene
(10 bar, ratio 1 : 1). After stirring the reaction mixture at 80 ЊC,
an off-white precipitate is formed which proved to be insoluble
in all common organic solvents and decomposes at 150 ЊC.
Treatment of 18 with a slight excess of SbiPr3 (molar ratio
1 : 2.3) in CH2Cl2 leads to bridge cleavage and formation of the
mono-nuclear compound 20a in 74% yield. Both the elemental
analysis and the mass spectrum (FAB) confirm the proposed
composition of the product. In contrast, the reaction of 19 with
SbiPr3 under the same conditions affords a mixture of two iso-
mers 21a and 21b, one of which contains the stibine ligand trans
to the AsiPr2 and the other trans to the PiPr2 unit. According to
the intensity of the signals for the AsCH2P methylene protons
in the 1H NMR spectrum at δ 3.39 and 3.24, the ratio of 21a to
21b is approximately 2 : 1.
The question which of the isomers 21a or 21b dominates has
been answered on the basis of the 13C NMR data as well as
DEPT 90 and DEPT 135 measurements. The most conclusive
result is that the signal for the SbCHCH3 carbon atom of the
major isomer 21a appears at δ 23.6 as a slightly broadened
singlet while that of the minor isomer 21b at δ 22.0 is a doublet
with a 13C–31P coupling constant of 6.9 Hz. The assignment of
the resonance at δ 23.6 to isomer 21a is supported by the obser-
vation that the 13C NMR spectrum of 20a exhibits for the
SbCHCH3 carbon nuclei a single resonance at δ 23.4, i.e., at
practically the same position as for 21a. In this context it
should be mentioned that the chloro-bridged complex [{Pd-
(µ-Cl)(κ2-Ph2AsCH2CH2PPh2)}2](ClO4)2 reacts with tertiary
phosphines PR3 to give also a mixture of two isomers
cis,trans-[PdCl(PR3)(κ2-Ph2AsCH2CH2PPh2)]ClO4 in which
that with PR3 in trans-disposition to AsPh2 dominates.14
The reaction of 18 and 19 with pyridine proceeds analo-
gously to that of 19 with SbiPr3 and affords a mixture of 22a,b
and 23a,b, respectively (see Scheme 4). In contrast to the NMR
spectra of 21a,b, which at room temperature show for most of
the 1H, 13C and 31P nuclei sharp resonances, the corresponding
spectra of 22a,b and 23a,b display at 295 K rather broad signals
indicating that in solution a relatively fast (on the NMR time
While the IR spectrum of the product shows a strong ν(C᎐O)
᎐
absorption at 1692 cmϪ1 (for comparison see ref. 11), the 13C
NMR spectrum (CP-MAS) displays two singlet resonances at
δ 209.3 and 35.4 assigned to the carbonyl and methylene (and
methyl) carbon atoms. In agreement with published data,12
these chemical shift values indicate that the polymeric material
is built up by alternating CO and C2H4 units. The average
molecular mass of the polyketone is 42390, determined by GPC
(gel permeation chromatography) measurements.
Preparation and substitution reactions of di-nuclear chelate
complexes
Both compounds 4 and 5 react with one equivalent of AgPF6
in acetone–CH2Cl2 to give instead of [PdCl(acetone)(κ2-R2-
AsCH2PiPr2)]PF6 the di-nuclear complexes 18 and 19 in 70–
80% yields (Scheme 4). Even in the presence of acetonitrile, the
solvent-free di-cationic species are formed, which is noteworthy
insofar as treatment of 4 and 5 with two equivalents of AgPF6
in CH3CN affords the mononuclear compounds 15 and 16 (see
Scheme 3). The chloro-bridged dimers 18 and 19 are yellow
solids, which are air-stable and readily soluble in polar solvents
such as acetone, chloroform and dichloromethane. The molar
conductivity of 18 (132.7 cm2 ΩϪ1 molϪ1) is almost the same as
that of the structurally related platinum() complex [{Pt(µ-I)-
(κ2-Ph2PCH2PPh2)}2](BF4)2 (129.2 cm2 ΩϪ1 molϪ1),13 both
values being determined in nitromethane. The 31P NMR spectra
of 18 and 19 display the resonance for the coordinated
1
scale) rearrangement takes place. The H NMR spectrum of
22a,b at 353 K in CD3NO2 shows sharp resonances (the number
of which is about half of that at 295 K) while the 31P NMR
spectrum of 22a,b at 353 K exhibits a broad bump at ca. δ Ϫ12.
At 295 K, the 31P NMR spectrum of 22a,b displays two broad-
ened singlets at δ Ϫ6.5 and Ϫ18.4. A high-temperature 13C
NMR spectrum of 22a,b could not be obtained due to continu-
ing decomposition of both isomers under these conditions in
nitromethane. Regarding the isomeric mixture 23a,b, the 13C
NMR spectrum shows at 213 K in CD2Cl2 rather sharp signals
which suggests that at this temperature the dynamic process is
significantly slowed down. Whether this process consists of an
intramolecular cis/trans isomerization or a dissociation of the
J. Chem. Soc., Dalton Trans., 2002, 2815–2824
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pyridine–palladium bond cannot be decided on the basis of the
present data.
A-Frame complexes with Pd–CH3 bonds and R2AsCH2PiPr2 as
bridging ligands
In contrast to the reaction of [PdCl(CH3)(η4-C8H12)] 24 with 3,
which leads to a mixture of products, treatment of 24 with an
equimolar amount of 2 in toluene affords cleanly the chelate
complex 25 (Scheme 5). The pale-yellow slightly air-sensitive
Fig. 4 Molecular structure of compound 27 [B(ArF)4 counterion
omitted for clarity]. Selected bond distances (Å) and angles (Њ): Pd(1)–
As(1) 2.4823(18), Pd(1)–P(2) 2.306(2), Pd(1)–C(1) 2.052(6), Pd(1)–Cl(1)
2.459(2), Pd(2)–As(2) 2.4678(18), Pd(2)–P(1) 2.301(2), Pd(2)–C(2)
2.064(6), Pd(2)–Cl(1) 2.460(3); As(1)–Pd(1)–P(2) 173.45(4), As(1)–
C(3)–P(1) 119.2(3), C(1)–Pd(1)–Cl(1) 176.3(2), Pd(1)–Cl(1)–Pd(2)
77.51(10), As(2)–Pd(2)–P(1) 173.44(4), As(2)–C(4)–P(2) 118.5(3), C(2)–
Pd(2)–Cl(1) 176.3(2).
The result of the X-ray crystal structure analysis of 27 is
shown in Fig. 4. The di-nuclear cation consists of two PdCH3
fragments which are bridged by two tBu2AsCH2PiPr2 ligands
and one chloride. The coordination geometry around the
palladium() centres is approximately square-planar with As–
Pd–P and C(1)–Pd–Cl bond angles of ca. 173.4 and 176.3Њ,
respectively. The Pd(1)–C(1) and Pd(2)–C(2) bond lengths of
2.052(6) and 2.064(6) Å are nearly identical to the Pd–CH3
bond length in the unsymmetrical hydrido(methyl) complex
[Pd2H(CH3)(µ-Cl)(µ-Ph2PCH2PPh2)2]BPh4 [2.050(11) Å].18
Moreover, the Pd–Pd distance of 3.079(4) Å is within the range
reported for other structurally related palladium compounds of
the A-frame type [2.976(6)–3.190(4) Å].18,19
To obtain the counterpart of 27 with two molecules of 3 as
bridging ligands, the preparative route used for 27 had to be
slightly modified. Following the observation that the mono-
nuclear chelate complex [PdCl(CH3)(κ2-iPr2AsCH2PiPr2)]
seems to be rather labile and undergoes subsequent reactions in
toluene even at room temperature, this compound was gener-
ated in situ from 24 and 3 in ether suspension. Treatment of the
suspension with a solution of Na[B(ArF)4] in ether affords a
pale-yellow solid of analytical composition [Pd2(CH3)2(µ-Cl)-
(µ-iPr2AsCH2PiPr2)2][B(ArF)4] consisting, however, in contrast
to 27 of a mixture of two isomers 28a and 28b (Scheme 6).
Scheme 5
solid was isolated in 83% yield. Owing to the NMR spectro-
scopic data of 25, there is no doubt that only one of the two
possible stereoisomers is formed. Since the doublet resonances
of the protons and the carbon atom of the Pd–CH3 moiety
in the 1H and 13C NMR spectra show rather small 1H–31P
and 13C–31P couplings (0.9 and 5.7 Hz, respectively), we
assume, in agreement with data from the literature,15 that
the metal-bonded methyl group and the PiPr2 unit are in
cis-disposition.
The methylpalladium() complex 25 reacts with AgBF4 in
acetonitrile at Ϫ30 ЊC to give, after warming to room temper-
ature and removal of the solvent, a white solid which due to the
1H, 13C and 31P NMR spectra consists of [Pd(CH3)(NCCH3)-
(κ2-tBu2AsCH2PiPr2)]BF4 26 as the main product. Diagnostic
features are the broadened singlet at δ Ϫ0.4 [with J(P,C) =
5.5 Hz] for the corresponding Pd–CH3 methyl carbon atom in
the 13C NMR and the singlet resonance at δ 24.3 for the PiPr2
phosphorus atom in the 31P NMR spectrum.
If instead of AgBF4, the sodium salt of Brookhart’s acid
Na[B(ArF)4] [ArF = C6H3(CF3)2-3,5] is used as substrate for the
reaction with 25, quite unexpectedly the A-frame type complex
27 is isolated in 74% yield (see Scheme 5). The composition of
the light red, moderately air-sensitive solid has been confirmed
by elemental analysis and mass spectra (FAB). The NMR data
of the di-nuclear cation indicate that only the head-to-tail iso-
mer with the phosphorus and the arsenic atoms trans to each
other is formed. The 31P NMR spectrum of 27 displays a singlet
at δ 30.6 which is shifted ca. 8 ppm downfield compared to 25.
1
In the H NMR spectrum of 27, the signal for the protons of
the Pd–CH3 group appears as a doublet at δ 0.93 with a 1H–31P
coupling constant (4.4 Hz) that is somewhat larger than for
the mono-nuclear compound 25 (0.9 Hz). The value of the
chemical shift for the Pd–CH3 resonance is similar to that of
the related A-frame complexes [Pd2(CH3)2(µ-X)(µ-Ph2PCH2-
PPh2)2]PF6 (X = Cl, Br) with dppm as the bridging ligand.16
With regard to the formation of 27 from 25 and Na[B(ArF)4]
we note that the platinum derivative [PtCl(CH3)(κ2-Ph2PCH2-
PPh2)] rearranges in methanol–CH2Cl2 at room temperature
completely to the thermodynamically more stable compound
[Pt2(CH3)2(µ-Cl)(µ-Ph2PCH2PPh2)2]Cl.17
Scheme 6
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Since the NMR data of the dominating species 28a are quite
similar to those of 27, we assume that 28a is the head-to-tail
isomer with the AsiPr2 and PiPr2 groups in trans-disposition.
The most typical features of the minor component 28b
(observed in the 1H- and 31P-decoupled 13C NMR spectrum of
the mixture 28a,b) are the two resonances for the metal-bonded
CH3 carbon atoms at δ Ϫ5.5 and Ϫ11.7, of which only the first
one shows in the 13C{1H} NMR spectrum a 13C–31P coupling.
The signal at δ Ϫ5.5 can therefore be assigned to the methyl
group cis to the PiPr2 and the other at δ Ϫ11.7 to the methyl
group cis to the AsiPr2 fragment. We found that in CD2Cl2 in
the temperature range of 20 to 40 ЊC no rearrangement of 28a
to 28b or vice versa occurs.
In summary, the work presented in this paper has shown that
the arsino(phosphino)methanes 2 and 3 with bulky alkyl
instead of phenyl substituents at the donor centres can behave
both as chelating and bridging ligands towards palladium().
Besides neutral and mono- as well as di-cationic compounds, in
which 2 and 3 are bonded in a chelating fashion, di-nuclear
complexes of the A-frame type with 2 and 3 as bridging units
can also be generated. While related compounds with dppm,
particularly in a bridging coordination mode, are well known
we note that prior to our investigations3,4 only a few examples
of dimeric rhodium or mixed platinum–rhodium compounds
with Ph2AsCH2PPh2 as the ligand have been described in
the literature.20 We are currently attempting to find out what
the catalytic potential of the rhodium() and palladium()
complexes with the new arsino(phosphino)methanes is and will
report on the results of these studies in due course.
d, J(P,H) = 9.7, PCH2As], 2.69 [2 H, sept, J(H,H) = 7.0,
AsCHCH3], 2.42–2.30 (2 H, m, PCHCH3], 1.44–1.38 (18 H, m,
br, AsCHCH3 and PCHCH3), 1.27 [6 H, dd, J(P,H) = 17.9,
J(H,H) = 7.0, PCHCH3]; δC (100.6 MHz) 30.3 (s, AsCHCH3),
26.2 [d, J(P,C) = 21.9, PCHCH3], 21.1 [d, J(P,C) = 21.0,
PCH2As], 20.2, 19.6 (both s, AsCHCH3), 18.8 (s, PCHCH3),
17.4 [d, J(P,C) = 1.9, PCHCH3]; NMR (CDCl3) δP (81.0 MHz)
Ϫ6.1 (s); NMR (CD2Cl2) δP (162.0 MHz) Ϫ6.9 (s).
[PdBr2(ꢀ2-tBu2AsCH2PiPr2)] 6. A solution of 4 (90 mg,
0.18 mmol) in acetone (6 cm3) was treated with KBr (107 mg,
0.90 mmol) and the reaction mixture was stirred for 90 min at
40 ЊC. After the solvent was evaporated in vacuo, the remaining
residue was washed twice with 10 cm3 portions of water. The
residue was dissolved in CH2Cl2 (10 cm3), the solution was dried
with Na2SO4 and then filtered. The filtrate was brought to dry-
ness in vacuo, the yellow solid was washed with pentane (5 cm3)
and dried. Yield 66 mg (63%); mp 219 ЊC (decomp.) (Found: C,
30.75; H, 5.82. C15H34AsBr2PPd requires: C, 30.72; H, 5.84%).
NMR (CD3NO2): δH (400 MHz) 3.28 [2 H, d, J(P,H) = 10.0 Hz,
PCH2As], 2.70–2.61 (2 H, m, PCHCH3), 1.56 (18 H, s, br,
AsCCH3), 1.48–1.38 (12 H, m, PCHCH3); δC (100.6 MHz) 47.0
(s, AsCCH3), 30.0 (s, AsCCH3), 28.3 [d, J(P,C) = 20.3,
PCHCH3], 23.1 [d, J(P,C) = 19.3, PCH2As], 19.8, 18.4 [both d,
J(P,C) = 2.0, PCHCH3]; δP (162.0 MHz) Ϫ12.3 (s).
[PdBr2(ꢀ2-iPr2AsCH2PiPr2)] 7. A solution of 5 (80 mg,
0.17 mmol) in acetone–CH2Cl2 (1 : 1, 12 cm3) was treated with
KBr (230 mg, 1.93 mmol) and the reaction mixture was stirred
for 12 h at room temperature. The solvent was evaporated
in vacuo, the residue was dissolved in CH2Cl2 (12 cm3) and the
solution was filtered. The filtrate was brought to dryness in
vacuo, the residue was washed with pentane (8 cm3) and then
dissolved in warm methanol (6 cm3, ca. 40 ЊC). The solution
was first cooled to room temperature and then stored for 6 h at
Ϫ78 ЊC. Small yellow crystals precipitated, which were separ-
ated from the mother liquor, washed with pentane (6 cm3) and
dried. Yield 56 mg (59%); mp 204 ЊC (decomp.) (Found: C,
27.77; H, 5.21. C13H30AsBr2PPd requires: C, 27.96; H, 5.41%).
NMR (CD2Cl2): δH (400 MHz) 3.03 [2 H, d, J(P,H) = 10.0,
PCH2As], 2.78 [2 H, sept, J(H,H) = 7.0, AsCHCH3), 2.52–2.39
(2 H, m, PCHCH3), 1.51–1.45 (18 H, m, br, AsCHCH3 and
PCHCH3), 1.33 [6 H, dd, J(P,H) = 17.6, J(H,H) = 6.8,
PCHCH3]; δC (100.6 MHz) 30.8 (s, AsCHCH3), 27.0 [d, J(P,C)
= 21.0, PCHCH3], 22.3 [d, J(P,C) = 20.0, PCH2As], 20.3, 19.7
(both s, AsCHCH3), 19.1 (s, br, PCHCH3), 17.5 [d, J(P,C) = 2.9
Hz, PCHCH3]; δP (162.0 MHz) Ϫ7.6 (s).
Experimental
All experiments were carried out under an atmosphere of
Argon by Schlenk techniques. The starting materials 1,21 12,22
2423 and the ligands 2 and 33 were prepared as described in the
literature. NMR spectra were recorded at room temperature on
Bruker AC 200, DRX 300, AMX 400 and DMX 600 instru-
ments, IR spectra on a Bruker IFS 25 FT-IR infrared spectro-
meter, and mass spectra on a Finnigan 90 MAT instrument
(70 eV). Conductivity measurements were carried out in
nitromethane with a Schott Konduktometer CG 851. Melting
points were measured by DTA. Abbreviations used: s, singlet; d,
doublet; q, quartet; sept, septet; m, multiplet; br, broadened
signal; coupling constants J in Hz.
Preparations
[PdCl2(ꢀ2-tBu2AsCH2PiPr2)] 4. A solution of compound 1
(277 mg, 0.72 mmol) in CH2Cl2 (10 cm3) was treated dropwise
with a solution of 2 (235 mg, 0.73 mmol) in CH2Cl2 (5 cm3) and
then stirred for 1 h at room temperature. The solution was fil-
tered and the filtrate was evaporated in vacuo. Pentane (20 cm3)
was added to the oily residue and the suspension irradiated in
an ultrasound bath for 30 min. A red–brown solid precipitated
which was separated from the mother liquor, washed twice with
5 cm3 portions of pentane and dried. Yield 270 mg (75%); mp
188 ЊC (decomp.) (Found: C, 36.06; H, 6.61. C15H34AsCl2PPd
requires: C, 36.20; H, 6.89%). NMR (CD2Cl2): δH (400 MHz)
2.94 [2 H, d, J(P,H) = 9.7, PCH2As], 2.66–2.54 (2 H, m,
PCHCH3), 1.56 (18 H, s, br, AsCCH3), 1.46–1.40 (12 H, m, br,
PCHCH3); δC (100.6 MHz) 45.4 (s, AsCCH3), 29.5 (s,
AsCCH3), 26.5 [d, J(P,C) = 19.1, PCHCH3], 21.4 [d, J(P,C) =
18.1, PCH2As], 19.2 [d, J(P,C) = 1.9, PCHCH3], 17.9 [d, J(P,C)
= 1.9, PCHCH3]; δP (162.0 MHz) Ϫ12.9 (s).
[PdI2(ꢀ2-tBu2AsCH2PiPr2)] 8. This compound was prepared
as described for 6 from 4 (80 mg, 0.16 mmol) and KI (133 mg,
0.80 mmol) in acetone (6 cm3) at room temperature; time of
reaction 48 h. Brown solid: yield 93 mg (85%); mp 137 ЊC
(decomp.) (Found: C, 26.48; H, 4.78. C15H34AsI2PPd requires:
C, 26.47; H, 5.04%). NMR (CD2Cl2): δH (400 MHz) 3.22 [2 H,
d, J(P,H) = 10.0, PCH2As], 2.71–2.61 (2 H, m, PCHCH3), 1.54
(18 H, s, br, AsCCH3), 1.43 [6 H, dd, J(P,H) = 18.2, J(H,H) =
7.0, PCHCH3], 1.39 [6 H, dd, J(P,H) = 19.4, J(H,H) = 7.4,
PCHCH3]; δC (100.6 MHz) 45.3 (s, AsCCH3), 29.4 (s,
AsCCH3), 27.7 [d, J(P,C) = 18.1, PCHCH3], 23.5 [d, J(P,C) =
16.2, PCH2As], 19.4 (s, br, PCHCH3), 17.8 [d, J(P,C) = 3.8,
PCHCH3]; δP (162.0 MHz) Ϫ15.0 (s).
[PdI2(ꢀ2-iPr2AsCH2PiPr2)] 9. This compound was prepared
as described for 7 from 5 (80 mg, 0.17 mmol) and NaI (300 mg,
2.00 mmol); time of reaction 48 h. Orange solid: yield 55 mg
(49%); mp 233 ЊC (decomp.) (Found: C, 24.22; H, 4.58.
C13H30AsI2PPd requires: C, 23.93; H, 4.63%). NMR (CD2Cl2):
δH (200 MHz) 3.19 [2 H, d, J(P,H) = 9.9, PCH2As], 2.78 [2 H,
sept, J(H,H) = 6.9, AsCHCH3], 2.55–2.32 (2 H, m, PCHCH3),
1.54–1.41 (18 H, m, br, AsCHCH3 and PCHCH3), 1.31 [6 H,
[PdCl2(ꢀ2-iPr2AsCH2PiPr2)] 5. This compound was prepared
as described for 4 from 1 (320 mg, 0.83 mmol) and 3 (245 mg,
0.83 mmol). Red solid: yield 310 mg (83%); mp 232 ЊC
(decomp.) (Found: C, 33.99; H, 6.25. C13H30AsCl2PPd requires:
C, 33.25; H, 6.44%). NMR (CD2Cl2): δH (400 MHz) 2.88 [2 H,
J. Chem. Soc., Dalton Trans., 2002, 2815–2824
2819

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dd, J(P,H) = 17.2, J(H,H) = 6.9, PCHCH3]; δC (50.3 MHz) 30.9
(s, AsCHCH3), 28.1 [d, J(P,C) = 19.4, PCHCH3], 24.5 [d, J(P,C)
= 18.5, PCH2As], 20.3, 19.6 (both s, AsCHCH3), 19.3 (s, br,
PCHCH3), 17.4 [d, J(P,C) = 1.8, PCHCH3]; δP (81.0 MHz)
Ϫ11.3 (s).
AsCCH3), 1.27–1.14 (12 H, m, PCHCH3); δC (100.6 MHz)
119.1 [d, J(P,C) = 7.6, C2 of C3H5], 66.4 [d, J(P,C) = 31.5, C1 of
C3H5], 63.7 [d, J(P,C) = 6.7, C3 of C3H5], 41.3, 41.2 [both d,
J(P,C) = 2.9, AsCCH3], 29.3, 29.2 (both s, AsCCH3), 27.6 [d,
J(P,C) = 20.0, PCH2As], 25.5–25.3 [m; in 13C{1H, 31P} two s at
25.3, 25.2, PCHCH3)], 20.2–20.0 [m; in 13C{1H, 31P} two s at
20.0, 19.9, PCHCH3)], 18.6, 18.4 (both s, PCHCH3); for
assignment of protons and carbon atoms of C3H5 see Chart 1;
δP (162.0 MHz) 12.5 (s, PCH2As), Ϫ144.3 [sept, J(F,P) = 712.8,
PF6]; MS (FAB): m/z 467 (Mϩ, 100.0%).
[Pd(CF3CO2)2(ꢀ2-tBu2AsCH2PiPr2)] 10. A solution of 4 (110
mg, 0.22 mmol) in CH2Cl2 (5 cm3) was treated at Ϫ40 ЊC with a
solution of CF3CO2Ag (98 mg, 0.44 mmol) in acetone (7 cm3).
After warming to room temperature the reaction mixture was
stirred for 4 h. The solvent was evaporated in vacuo, the remain-
ing residue was dissolved in CH2Cl2 (10 cm3) and the solution
was filtered. The filtrate was brought to dryness in vacuo, the
residue was washed with pentane (8 cm3), and then methanol
(3 cm3) was added. The suspension was filtered and the filtrate
was stored for 12 h at Ϫ78 ЊC. A pale-yellow solid precipitated,
which was separated from the mother liquor, washed with pen-
tane (8 cm3) and dried. Yield 80 mg (56%); mp 195 ЊC
(decomp.); Λ = 25.3 cm2 ΩϪ1 molϪ1 (Found: C, 35.04; H, 5.35.
C19H34AsF6O4PPd requires: C, 34.96; H, 5.25%). IR (Nujol)
ν(OCO)asym 1687, ν(OCO)sym 1413 cmϪ1; NMR (CD2Cl2):
δH (300 MHz) 2.87 [2 H, d, J(P,H) = 10.0, PCH2As], 2.70–2.53
(2 H, m, PCHCH3), 1.54 (18 H, s, br, AsCCH3), 1.43 [6 H, dd,
J(P,H) = 18.5, J(H,H) = 7.4, PCHCH3], 1.36 [6 H, dd, J(P,H) =
17.9, J(H,H) = 7.2, PCHCH3]; δC (75.5 MHz) 161.3 [q, J(F,C) =
36.0, CF3CO2], 116.4 [q, J(F,C) = 291.5, CF3CO2], 46.3 (s,
AsCCH3), 29.4 (s, AsCCH3), 27.5 [d, J(P,C) = 21.4, PCHCH3],
20.1 [d, J(P,C) = 21.1, PCH2As], 19.3 [d, J(P,C) = 1.8,
PCHCH3], 18.1 [d, J(P,C) = 1.5, PCHCH3]; δF (282.4 MHz)
Ϫ75.3 (s); δP (81.0 MHz) Ϫ11.7 (s).
[Pd(ꢁ3-C3H5)(ꢀ2-iPr2AsCH2PiPr2)]PF6 14. This compound
was prepared as described for 13 from 12 (53 mg, 0.14 mmol)
and 3 (106 mg, 0.36 mmol) in CH2Cl2 (4 cm3) plus a solution
of NH4PF6 (235 mg, 1.44 mmol) in methanol (3 cm3). White
solid: yield 123 mg (72%); mp 190 ЊC (decomp.) (Found: C,
32.6; H, 5.75; Pd, 19.02. C16H35AsF6P2Pd requires: C, 32.87; H,
6.03; Pd, 18.20%). NMR (CDCl3): δH (400 MHz) 5.26–5.15
(1 H, m, br, H2 of C3H5), 4.70–4.67 (1 H, m, br, H1s of
C3H5), 4.55–4.54 (1 H, m, br, H3s of C3H5), 3.39, 3.34 [1 H each,
1
m; in H{31P} AB-spin system, J(A,B) = 15.6, PCH2As], 3.01–
2.95 (1 H, m, H1a of C3H5), 2.90 (1 H, m, br, H3a of C3H5), 2.60–
2.42 (2 H, m, br, AsCHCH3), 2.30–2.12 (2 H, m, br, PCHCH3),
1.32–1.09 (24 H, m, br, AsCHCH3 and PCHCH3); δC (100.6
MHz) 119.3 [d, J(P,C) = 8.1, C2 of C3H5], 68.1 [d, J(P,C) = 30.5,
C1 of C3H5], 62.8 [d, J(P,C) = 6.1, C3 of C3H5], 27.8 (s, br,
AsCHCH3), 26.0 [d, J(P,C) = 20.3, PCH2As], 25.6 [d, J(P,C) =
23.0, PCHCH3], 25.4 [d, J(P,C) = 22.4, PCHCH3], 20.2, 20.1,
18.8, 18.7, 18.6 (all s, AsCHCH3 and PCHCH3); for assign-
ment of protons and carbon atoms of C3H5 see Chart 1; δP
(162.0 MHz) 16.6 (s, PCH2As), Ϫ144.3 [sept, J(F,P) = 712.8,
PF6].
[Pd(CF3CO2)2(ꢀ2-iPr2AsCH2PiPr2)] 11. This compound was
prepared as described for 10 from 5 (80 mg, 0.17 mmol) and
CF3CO2Ag (75 mg, 0.34 mmol). Pale-yellow solid: yield 96 mg
(90%); mp 107 ЊC (decomp.); Λ = 24.1 cm2 ΩϪ1 molϪ1 (Found:
C, 32.4; H, 4.76. C17H30AsF6O4PPd requires: C, 32.69; H,
[Pd(NCCH3)2(ꢀ2-tBu2AsCH2PiPr2)](PF6)2 15. A solution of 4
(100 mg, 0.20 mmol) in CH2Cl2 (5 cm3) was treated at Ϫ30 ЊC
with a solution of AgPF6 (100 mg, 0.40 mmol) in CH3CN
(5 cm3). After the reaction mixture was warmed to room tem-
perature, it was stirred for 1 h. The solvent was evaporated
in vacuo, the residue was suspended in CH2Cl2 (8 cm3) and the
solution was filtered. The filtrate was concentrated in vacuo to
ca. 1.5 cm3 and diethyl ether (15 cm3) was added dropwise. An
oily solid precipitated, which was separated from the mother
liquor and washed three times with diethyl ether (8 cm3). After
it was stored for 12 h at 0 ЊC, a yellow solid was formed. Yield
133 mg (83%); mp 98 ЊC (decomp.); Λ = 157 cm2 ΩϪ1 molϪ1
(Found: C, 28.48; H, 4.75; N, 3.42; Pd, 13.03. C19H40AsF12-
N2P3Pd requires: C, 28.57; H, 5.05; N, 3.51; Pd, 13.32%). NMR
(CD3NO2): δH (400 MHz) 3.41 [2 H, d, J(P,H) = 10.6, PCH2As],
2.80–2.68 (2 H, m, PCHCH3), 2.43 (6 H, s, br, CH3CN), 1.62
(18 H, s, br, AsCCH3), 1.50–1.42 (12 H, m, PCHCH3); δC (100.6
MHz) 125.3 (m, CH3CN), 50.4 (s, AsCCH3), 29.4 (s, AsCCH3),
28.1 [d, J(P,C) = 21.4, PCHCH3], 19.5 [d, J(P,C) = 25.4,
PCH2As], 18.7 [d, J(P,C) = 2.0, PCHCH3], 18.5 (s, PCHCH3),
2.4 (s, br, CH3CN); δP (162.0 MHz) Ϫ16.1 (s, PCH2As), Ϫ144.6
[sept, J(F,P) = 706.3, PF6].
4.84%). IR (Nujol) ν(OCO)asym 1686, ν(OCO)sym 1410 cmϪ1
;
NMR (CD2Cl2): δH (400 MHz) 2.95 [2 H, sept, J(H,H) = 7.0,
AsCHCH3], 2.75 [2 H, d, J(P,H) = 10.2, PCH2As], 2.54–2.45
(2 H, m, PCHCH3), 1.50–1.26 (24 H, m, AsCHCH3 and
PCHCH3); δC (75.5 MHz) 161.6 [q, br, J(F,C) = 6.7, CF3CO2],
116.2 [q, br, J(F,C) = 290.6, CF3CO2], 33.3 (s, AsCHCH3), 26.8
[d, J(P,C) = 22.5, PCHCH3], 21.4, 19.2 (both s, AsCHCH3),
19.1 (s, br, PCHCH3), 18.0 [d, J(P,C) = 21.0, PCH2As], 17.5 [d,
J(P,C) = 2.5, PCHCH3]; δF (282.4 MHz) Ϫ75.0 (s); δP (162.0
MHz) Ϫ2.9 (s).
[Pd(ꢁ3-C3H5)(ꢀ2-tBu2AsCH2PiPr2)]PF6 13. A solution of 12
(78 mg, 0.21 mmol) in CH2Cl2 (4 cm3) was treated with a solu-
tion of 2 (170 mg, 0.53 mmol) in CH2Cl2 (6 cm3) and stirred at
room temperature. After 3 h a solution of NH4PF6 (340 mg,
2.10 mmol) in methanol (3 cm3) was added dropwise and the
reaction mixture was stirred for 12 h. The solvent was evapor-
ated in vacuo, the residue was suspended in CH2Cl2 (8 cm3) and
the solution was filtered. The filtrate was brought to dryness in
vacuo, the oily residue was treated with pentane (8 cm3) and the
mixture was irradiated for 20 min in an ultrasound bath. An
off-white solid was formed, which was separated from the
mother liquor, dried, and then dissolved in warm (ca. 40 ЊC)
ethyl acetate (4 cm3). Upon storing the solution for 12 h at
Ϫ78 ЊC, a white microcrystalline solid precipitated, which was
washed twice with pentane (8 cm3) and dried. Yield 136 mg
(53%); mp 142 ЊC (decomp.); Λ = 72.8 cm2 ΩϪ1 molϪ1 (Found:
C, 34.52; H, 6.26. C18H39AsF6P2Pd requires: C, 35.28; H,
6.42%). NMR (CDCl3): δH (400 MHz) 5.25–5.15 (1 H, m, H2 of
C3H5), 4.67–4.63 (1 H, m, H1s of C3H5), 4.58–4.46 (1 H, m, H3s
of C3H5), 3.47, 3.41 [1 H each, ABX spin system; in 1H{31P} AB
spin system, J(A,B) = 15.9, PCH2As], 2.98–2.88 (2 H, m, H1a
and H3a of C3H5), 2.36, 2.24 [1 H each, both m; in 1H{31P} both
sept, J(H,H) = 7.6, PCHCH3], 1.37, 1.29 (9 H each, both s,
[Pd(NCCH3)2(ꢀ2-iPr2AsCH2PiPr2)](PF6)2 16. This com-
pound was prepared as described for 15 from 5 (100 mg, 0.22
mmol) and AgPF6 (104 mg, 0.41 mmol). Yellow solid: yield 79
mg (47%); mp 64 ЊC (decomp.) (Found: C, 26.21; H, 4.48; N,
3.45. C17H36AsF12N2P3Pd requires: C, 26.49; H, 4.71; N,
3.63%). NMR (CD3NO2): δH (400 MHz) 3.40 [2 H, d, J(P,H) =
10.6, PCH2As], 3.12 [2 H, sept, J(H,H) = 7.0, AsCHCH3], 2.67–
2.56 (2 H, m, PCHCH3), 2.41 (6 H, s, br, CH3CN), 1.52 [12 H,
d, J(H,H) = 7.0, AsCHCH3], 1.47 [6 H, dd, J(P,H) = 20.5,
J(H,H) = 7.0, PCHCH3], 1.41 [6 H, dd, J(P,H) = 19.9, J(H,H) =
6.7, PCHCH3]; δC (100.6 MHz) 125.4 (m, br, CH3CN), 33.8 (s,
AsCHCH3), 27.5 [d, J(P,C) = 22.9, PCHCH3], 20.2, 19.9 (both
s, AsCHCH3), 18.7 (s, PCHCH3), 18.4 [d, J(P,C) = 25.8,
PCH2As], 17.7 [d, J(P,C) = 1.9, PCHCH3], 2.5 (s, br, CH3CN);
2820
J. Chem. Soc., Dalton Trans., 2002, 2815–2824

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δP (162.0 MHz) Ϫ8.6 (s, PCH2As), Ϫ144.6 [sept, J(F,P) = 708.4,
PF6].
Λ = 69.2 cm2 ΩϪ1 molϪ1 (Found: C, 33.34; H, 6.18; Pd, 13.01.
C24H55AsClF6P2PdSb requires: C, 33.59; H, 6.46; Pd, 12.40%).
NMR (CD2Cl2): δH (400 MHz) 3.26 [2 H, d, J(P,H) = 10.3,
PCH2As], 2.71 [3 H, sept, J(H,H) = 7.3, SbCHCH3], 2.39–2.26
(2 H, m, PCHCH3), 1.59 (18 H, s, br, AsCCH3), 1.53 [18 H, d,
J(H,H) = 7.3, SbCHCH3], 1.48 [6 H, dd, J(P,H) = 19.0, J(H,H)
= 7.3, PCHCH3], 1.36 [6 H, dd, J(P,H) = 17.0, J(H,H) = 7.0,
PCHCH3]; δH (100.6 MHz) 47.6 (s, AsCCH3), 30.0 (s,
[Pd(ꢀ2-acac)(ꢀ2-tBu2AsCH2PiPr2)]PF6 17. A solution of 15
(45 mg, 0.06 mmol) in methanol (5 cm3) was treated at Ϫ60 ЊC
with Na(acac) (10 mg, 0.08 mmol). After the reaction mixture
was warmed to room temperature, it was stirred for 30 min and
then the solvent was evaporated in vacuo. The residue was sus-
pended in CH2Cl2 (7 cm3) and the solution was filtered. The
filtrate was brought to dryness in vacuo, the white solid was
washed twice with pentane (5 cm3) and dried. Yield 30 mg
(79%); mp 183 C (decomp.) (Found: C, 36.10; H, 5.90.
C20H41AsF6O2P2Pd requires: C, 35.81; H, 6.16%). IR (KBr)
ν(CO) 1570, 1521 cmϪ1; NMR (CD2Cl2): δH (400 MHz) 5.46
(1 H, s, CH of acac), 3.08 [2 H, d, J(P,H) = 10.0, PCH2As],
2.52–2.42 (2 H, m, PCHCH3), 2.00, 1.98 (3 H each, both s, CH3
of acac), 1.56 (18 H, s, AsCCH3), 1.45 [6 H, dd, J(P,H) = 18.5,
J(H,H) = 7.3, PCHCH3], 1.39 [6 H, dd, J(P,H) = 17.6, J(H,H) =
7.3, PCHCH3]; δC (50.3 MHz) 186.8 [d, J(P,C) = 1.9, CH3C2O
of acac], 186.4 (br s, CH3C4O of acac), 99.3 (s, C3 of acac), 45.6
(s, AsCCH3), 29.4 (s, AsCCH3) 27.2 (m, C1 and C5 of acac),
26.5 [d, J(P,C) = 20.3, PCHCH3], 21.1 [d, J(P,C) = 23.1,
PCH2As], 18.7 (s, PCHCH3), 18.3 [d, J(P,C) = 2.8, PCHCH3],
for assignment of carbon atoms of acac see Chart 1; δP (162.0
MHz) Ϫ14.0 (s, PCH2As), Ϫ144.4 [sept J(F,P) = 712.3, PF6];
MS (FAB): m/z 525 (Mϩ, 7.9%).
AsCCH3), 29.2 [d, J(P,C)
= 20.0, PCHCH3], 23.4 (s,
SbCHCH3), 22.4 (s, SbCHCH3), 21.1 (s, PCHCH3), 20.5 [d,
J(P,C) = 21.0, PCH2As], 18.3 [d, J(P,C) = 2.9, PCHCH3]; δP
(162.0 MHz) 2.3 (s, PCH2As), Ϫ144.4 [sept, J(F,P) = 710.6,
PF6]; MS (FAB): m/z 713 (Mϩ, 10.6%).
[PdCl(SbiPr3)(ꢀ2-iPr2AsCH2PiPr2)]PF6 21a,b. This mixture
of two isomers was prepared as described for 20a from 19
(80 mg, 0.07 mmol) and SbiPr3 (0.03 cm3, 0.16 mmol) in CH2Cl2
(4 cm3). After recrystallization from methanol (2 cm3) red crys-
tals were obtained. Yield 69 mg (60%); mp 106 ЊC (decomp.)
(Found: C, 31.70; H, 5.82. C22H51AsClF6P2PdSb requires: C,
31.83; H, 6.19%). NMR (CD2Cl2): δH (600 MHz) 3.39 [d, J(P,H)
= 10.0, PCH2As of isomer B], 3.24 [d, J(P,C) = 10.2, PCH2As of
isomer A], 2.92–2.85, 2.74–2.65, 2.63–2.53, 2.28–2.20 (all m, br,
AsCHCH3, PCHCH3, SbCHCH3 of isomers A and B), 1.54–
1.31 (m, br, AsCHCH3, PCHCH3, SbCHCH3 of isomers A und
B); δC (150.9 MHz) 32.1 (s, AsCHCH3 of isomer B), 31.8 (s,
AsCHCH3 of isomer A), 28.5 [d, J(P,C) = 21.3, PCHCH3 of
isomer A], 27.2 [d, J(P,C) = 15.8, PCHCH3 of isomer B], 23.6 (s,
br, SbCHCH3 of isomer A), 22.45 (s, br, SbCHCH3 of isomer
A), 22.4 (s, br, SbCHCH3 of isomer A), 22.0 [d, J(P,C) = 6.9,
SbCHCH3 of isomer B], 21.4 [d, J(P,C) = 19.9, PCH2As of
isomer B], 21.2 (s, AsCHCH3 or PCHCH3 of isomer B), 21.0
[d, J(P,C) = 24.0, PCH2As of isomer A], 20.4 (s, AsCHCH3 of
isomer A), 20.2 [d, J(P,C) = 3.0, PCHCH3 of isomer A], 20.1 (s,
AsCHCH3 of isomer A), 19.4, 19.0 (both s, AsCHCH3 and
PCHCH3 of isomer B), 17.8 [d, J(P,C) = 1.8, PCHCH3 of iso-
mer B], 17.6 [d, J(P,C) = 2.9, PCHCH3 of isomer A]; δP (162.0
MHz) 5.3 (s, PCH2As of isomer A), Ϫ14.2 (s, PCH2As of
isomer B), Ϫ144.4 [sept, J(F,P) = 710.6, PF6].
[{Pd(ꢂ-Cl)(ꢀ2-tBu2AsCH2PiPr2)}2](PF6)2 18. A solution of 4
(150 mg, 0.30 mmol) in CH2Cl2 (5 cm3) was treated at Ϫ40 ЊC
with a solution of AgPF6 (76 mg, 0.30 mmol) in acetone
(5 cm3). After the reaction mixture was warmed to room
temperature, it was stirred for 1 h. The solvent was evaporated
in vacuo, the residue was dissolved in CH2Cl2 (10 cm3) and the
solution was filtered. The filtrate was brought to dryness
in vacuo, the pale-yellow solid was washed twice with pentane
(10 cm3) and dried. Yield 145 mg (80%); mp 159 ЊC (decomp.);
Λ = 132.7 cm2 ΩϪ1 molϪ1 (Found: C, 29.68; H, 5.40. C30H68As2-
Cl2F12P4Pd2 requires: C, 29.67; H, 5.64%). NMR (CD2Cl2):
δH (400 MHz) 3.31 [4 H, d, J(P,H) = 10.6, PCH2As], 2.65–2.52
(4 H, m, PCHCH3), 1.59 (36 H, s, AsCCH3), 1.49–1.41 (24 H,
m, PCHCH3); δC (100.6 MHz) 49.8 (s, br, AsCCH3), 29.7 (s,
AsCCH3), 28.1 [d, J(P,C) = 20.0, PCHCH3], 21.2 [d, J(P,C) =
24.8, PCH2As], 18.9 [d, J(P,C) = 2.9, PCHCH3], 18.7 (br s,
PCHCH3); δP (162.0 MHz) Ϫ12.1 (s, PCH2As), Ϫ144.3 [sept,
J(F,P) = 712.8, PF6].
[PdCl(py)(ꢀ2-tBu2AsCH2PiPr2)]PF6 22a,b. A solution of 18
(50 mg, 0.04 mmol) in CH2Cl2 (3 cm3) was treated at Ϫ50 ЊC
with pyridine (0.01 cm3, 0.12 mmol). After the reaction mixture
was warmed to room temperature, it was stirred for 2 h. The
solvent was evaporated in vacuo, the oily residue was layered
with pentane (6 cm3) and the suspension was irradiated for
20 min in an ultrasound bath. A brownish solid was formed,
which was separated from the mother liquor, washed twice with
pentane (5 cm3) and dried. Yield 55 mg (93%); mp 72 ЊC
(decomp.) (Found: C, 34.66; H, 5.30; N, 2.17. C20H39AsClF6-
NP2Pd requires C, 35.00; H, 5.73; N, 2.04%). NMR (CD2Cl2,
295 K): δH (400 MHz) 8.67 (m, ortho-H of C5H5N), 7.96 (m,
para-H of C5H5N), 7.58 (m, meta-H of C5H5N), 3.20 [d, br,
J(P,H) = 10.3, PCH2As], 2.75 (m, PCHCH3 of isomer A), 2.57
(m, PCHCH3 of isomer B), 1.63–1.20 (m, br, AsCCH3 and
PCHCH3); δC (100.6 MHz) 151.2 (m, ortho-C of C5H5N), 139.8
(m, para-C of C5H5N), 126.4 (m, meta-C of C5H5N), 47.2 (m,
AsCCH3 of isomer B), 46.0 (m, AsCCH3 of isomer A), 29.6 (s,
AsCCH3), 26.7 (m, br, PCHCH3), 20.4 (m, br, PCH2As), 19.2,
17.6 (both s, br, PCHCH3 of isomer A), 18.8, 17.9 (both s, br,
PCHCH3 of isomer B); δP (162.0 MHz) Ϫ6.5 (s, br, PCH2As of
isomer A), Ϫ18.4 (s, br, PCH2As of isomer B), Ϫ144.3 [sept,
J(F,P) = 710.6, PF6]; NMR (CD3NO2, 353 K): δH (200 MHz)
8.75 (2 H, m, ortho-H of C5H5N), 8.07 (1 H, m, para-H of
C5H5N), 7.65 (2 H, m, meta-H of C5H5N), 3.37 [2 H, d, J(P,H) =
10.6, PCH2As], 2.90–2.65 (2 H, m, br, PCHCH3), 1.63 (18 H, s,
AsCCH3), 1.61–1.32 (12 H, m, br, PCHCH3).
[{Pd(ꢂ-Cl)(ꢀ2-iPr2AsCH2PiPr2)}2](PF6)2 19. This compound
was prepared as described for 18 from 5 (315 mg, 0.67 mmol)
and AgPF6 (169 mg, 0.67 mmol) in CH2Cl2–acetone (16 cm3,
1 : 1). Yellow solid: yield 268 mg (69%); mp 118 ЊC (decomp.)
(Found C, 27.14; H, 4.94; Pd, 18.27. C26H60As2Cl2F12P4Pd2
requires: C, 26.96; H, 5.22; Pd, 18.38%). NMR (CD2Cl2):
δH (400 MHz) 3.35 [4 H, d, J(P,H) = 10.2, PCH2As], 2.96 [4 H,
sept, J(H,H) = 7.0, AsCHCH3], 2.50–2.40 (4 H, m, PCHCH3),
1.52–1.39 (48 H, m, AsCHCH3 and PCHCH3); δC (100.6 MHz)
33.2 (s, AsCHCH3), 27.0 [d, J(P,C) = 22.4, PCHCH3], 20.2
(m, PCH2As), 20.1, 20.0 (both s, br, AsCHCH3), 18.5 (s,
PCHCH3), 17.7 (s, br, PCHCH3); δP (162.0 MHz) Ϫ4.7 (s,
PCH2As), Ϫ144.4 [sept, J(F,P) = 710.6, PF6].
[PdCl(SbiPr3)(ꢀ2-tBu2AsCH2PiPr2)]PF6 20a. A solution of
18 (70 mg, 0.06 mmol) in CH2Cl2 (3 cm3) was treated at Ϫ50 ЊC
with SbiPr3 (0.03 cm3, 0.14 mmol). After the reaction mixture
was warmed to room temperature, it was stirred for 45 min. A
change of color from yellow to deep red occurred. The solvent
was evaporated in vacuo, the oily residue was layered with pen-
tane (5 cm3) and the suspension was irradiated for 15 min in an
ultrasound bath. A pale-yellow solid was formed, which was
separated from the mother liquor, washed twice with pentane
(5 cm3) and dried. Yield 76 mg (74%); mp 68 ЊC (decomp.);
[PdCl(py)(ꢀ2-iPr2AsCH2PiPr2)]PF6 23a,b. This mixtures
of two isomers was prepared as described for 22a,b from 19
J. Chem. Soc., Dalton Trans., 2002, 2815–2824
2821

View Article Online
(90 mg, 0.08 mmol) and pyridine (0.02 cm3, 0.20 mmol) in
CH2Cl2 (4 cm3). Light red solid: yield 55 mg (54%); mp 88 ЊC
(decomp.) (Found: C, 33.10; H, 5.08; N, 2.19. C18H35AsClF6-
NP2Pd requires: C, 32.85; H, 5.36; N. 2.13%). NMR (CD2Cl2,
295 K): δH (300 MHz) 8.63 (2 H, m, ortho-H of C5H5N), 7.96
(1 H, m, para-H of C5H5N), 7.57 (2 H, m, meta-H of C5H5N),
3.19 [2 H, d, J(P,H) = 10.2, PCH2As], 3.00–2.75, 2.65–2.35
(2 H each, both m, br, AsCHCH3 and PCHCH3), 1.65–1.15 (24
H, m, br, AsCHCH3 and PCHCH3); δC (75.5 MHz) 151.4
(s, ortho-C of C5H5N), 140.0 (s, para-C of C5H5N), 126.5 (s,
meta-C of C5H5N), 31.5 (s, br, AsCHCH3 of isomer B), 30.5 (s,
br, AsCHCH3 of isomer A), 26.5 [d, br, J(P,C) = 21.8, PCHCH3
of isomer A], 25.4 (m, br, PCHCH3 of isomer B), 20.3, 19.8
(both s, AsCHCH3), 19.4 (m, br, PCH2As), 19.0, 17.4 (both s,
br, PCHCH3); δP (81.0 MHz) Ϫ0.5 (s, PCH2As of isomer A),
Ϫ11.1 (s, PCH2As of isomer B), Ϫ143.9 [sept, J(F,P) = 711.9,
PF6]; NMR (CD2Cl2, 213 K) δH (300 MHz) 8.55 (m, ortho-H of
C5H5N), 7.94 (m, para-H of C5H5N), 7.56 (m, meta-H of
C5H5N), 3.13 (m, br, PCH2As of isomers A and B), 2.94–2.77,
2.60–2.40, 2.30–2.25 (all m, br, AsCHCH3 and PCHCH3 of
isomers A and B), 1.50–1.00 (m, br, AsCHCH3 and PCHCH3
of isomers A and B); δC (75.5 MHz) 150.5 (s, ortho-C of C5H5N
of isomer A), 150.4 (s, ortho-C of C5H5N of isomer B), 139.5 (s,
para-C of C5H5N of isomer B), 139.4 (s, para-C of C5H5N of
isomer A), 126.2 (s, meta-C of C5H5N of isomer B), 125.8 [d,
J(P,C) = 2.5, meta-C of C5H5N of isomer A], 30.1 (s, br,
AsCHCH3 of isomer B), 29.2 (s, br, AsCHCH3 of isomer A),
25.3 [d, J(P,C) = 24.0, PCHCH3 of isomer A], 23.7 [d, J(P,C) =
21.1, PCHCH3 of isomer B], 19.4 (s, br, AsCHCH3 or
PCHCH3 of isomers A and B), 19.0 (s, AsCHCH3 or PCHCH3
of isomer B), 18.9 (s, AsCHCH3 or PCHCH3 of isomer A),
18.2 (m, PCH2As of isomer B), 18.0 (s, AsCHCH3 or PCHCH3
of isomer A), 17.6 [d, J(P,C) = 23.3, PCH2As of isomer A], 17.3
(s, br, AsCHCH3 or PCHCH3 of isomer B), 16.6 [d, J(P,C) =
1.8, PCHCH3 of isomer A], 16.3 (s, br, PCHCH3 of isomer B);
δP (81.0 MHz) Ϫ2.1 (s, PCH2As of isomer A), Ϫ10.1 (s,
PCH2As of isomer B), Ϫ144.2 [sept J(F,P) = 711.9, PF6].
by fractional crystallization failed. Data for 26: NMR
(CD2Cl2): δH (300 MHz) 2.80 [2 H, d, J(P,H) = 10.1, PCH2As],
2.50–2.36 (2 H, m, br, PCHCH3), 2.35 (3 H, s, br, CH3CN),
1.48–1.25 (12 H, m, PCHCH3), 1.41 (18 H, s, AsCCH3), 0.62 (3
H, s, br, PdCH3); δC (75.5 MHz) 122.7 (m, CH3CN), 40.6 [d,
J(P,C) = 1.8, AsCCH3], 29.7 (s, AsCCH3), 26.6 [d, J(P,C) = 22.2,
PCHCH3], 21.3 [d, J(P,C) = 21.8, PCH2As], 19.7 (s, PCHCH3),
18.4 [d, J(P,C) = 1.1, PCHCH3], 3.0 (s, br, CH3CN), Ϫ0.4 [d,
J(P,C) = 5.5, PdCH3]; δP (81.0 MHz) 24.3 (s).
[Pd2(CH3)2(ꢂ-Cl)(ꢂ-tBu2AsCH2PiPr2)2][B(ArF)4] 27. A solu-
tion of 25 (100 mg, 0.21 mmol) (55) in diethyl ether (5 cm3) was
treated with a solution of Na[B(ArF)4] (92 mg, 0.10 mmol) in
diethyl ether (6 cm3) and stirred for 1 h at room temperature. An
off-white solid precipitated. The solution was filtered, the fil-
trate was concentrated in vacuo to ca. 3 cm3 and then stored for
3 d at Ϫ78 ЊC. A pale-red microcrystalline solid was formed,
which was separated from the mother liquor, washed twice with
pentane (5 cm3) and dried. Yield 139 mg (74%); mp 70 ЊC
(decomp.) (Found: C, 42.71; H, 4.53. C64H86As2BClF24P2Pd2
requires: C, 43.13; H, 4.86). NMR (CD2Cl2): δH (400 MHz) 7.74
[8 H, s, br, ortho-H of B(ArF)4], 7.58 [4 H, s, br, para-H of
1
B(ArF)4], 2.75 [2 H, m, in H{31P} d, J(H,H) = 14.0, PCH2As],
2.61, 2.44 [2 H each, m, in 1H{31P} sept, J(H,H) = 7.0,
PCHCH3], 2.19 [2 H, m, in 1H{31P} d, J(H,H) = 12.5, PCH2As],
1.49 (12 H, m, PCHCH3), 1.47, 1.44 (18 H each, both s, br,
AsCCH3), 1.36 [6 H, dd, J(P,H) = 11.2, J(H,H) = 7.0,
PCHCH3], 1.28 [6 H, dd, J(P,H) = 16.1, J(H,H) = 7.3,
PCHCH3], 0.93 [6 H, d, J(P,H) = 4.4, PdCH3]; δC (100.6 MHz)
162.1 [q, J(B,C) = 49.6, ipso-C of B(ArF)4], 135.1 [s, br, ortho-C
of B(ArF)4], 129.2 [qq, J(F,C) = 31.5, J(B,C) = 2.9, meta-C of
B(ArF)4], 124.9 [q, J(F,C) = 272.8, CF3], 117.8 [m, br, para-C of
B(ArF)4], 41.9 [m, X-part of ABX spin system, in 13C{1H,31P}
s, AsCCH3], 40.3 [m, br, X-part of ABX spin system, in
13C{1H,31P} s, AsCCH3], 31.4, 30.0 (both s, AsCCH3), 28.6 [d,
J(P,C) = 21.0, PCHCH3], 23.2 [d, J(P,C) = 19.1, PCHCH3], 23.1
[d, J(P,C) = 3.8, PCHCH3], 21.2, 18.9 [both d, J(P,C) = 1.9,
PCHCH3], 17.6 [d, J(P,C) = 7.6, PCHCH3], 13.0 [m, X-part of
ABX spin system, in 13C{1H,31P} s, PCH2As], Ϫ6.4 (s, br,
PdCH3); δF (376.4 MHz) Ϫ62.7 (s, CF3); δP (162.0 MHz) = 30.6
(s); MS (FAB): m/z 919 (Mϩ, 6.3%).
[PdCl(CH3)(ꢀ2-tBu2AsCH2PiPr2)] 25. A solution of 24 (130
mg, 0.49 mmol) in toluene (6 cm3) was treated with a solution
of 2 (185 mg, 0.58 mmol) in toluene (6 cm3) and stirred for 30
min at room temperature. The solvent was evaporated in vacuo,
the residue was suspended in pentane (5 cm3) and the suspen-
sion was irradiated for 20 min in an ultrasound bath. A pale-
yellow solid precipitated, which was separated from the mother
liquor, washed twice with pentane (5 cm3) and dried. Yield 194
mg (83%); mp 64 ЊC (decomp.) (Found: C, 40.56; H, 7.82; Pd,
23.25. C16H37AsClPPd requires: C, 40.27; H, 7.81; Pd, 22.30%).
NMR (CDCl3): δH (400 MHz) 2.58 [2 H, d, J(P,H) = 10.0,
PCH2As], 2.56–2.39 (2 H, m, br, PCHCH3), 1.38 (18 H, s,
AsCCH3), 1.30 [6 H, dd, J(P,H) = 16.4, J(H,H) = 7.3,
PCHCH3], 1.28 [6 H, dd, J(P,H) = 15.3, J(H,H) = 7.3,
PCHCH3], 0.73 [3 H, d, J(P,H) = 0.9, PdCH3]; δC (100.6 MHz)
39.4 [d, J(P,C) = 2.9, AsCCH3], 29.8 (s, AsCCH3), 26.3 [d,
J(P,C) = 19.1, PCHCH3], 21.2 [d, J(P,C) = 18.1, PCH2As], 19.7,
18.6 (both s, PCHCH3), 0.9 [d, J(P,C) = 5.7, PdCH3]; δP (162.0
MHz) 22.1 (s).
[Pd2(CH3)2(ꢂ-Cl)(ꢂ-iPr2AsCH2PiPr2)2]B(ArF)4 28a,b. A solu-
tion of 24 (60 mg, 0.23 mmol) in diethyl ether (5 cm3) was
treated at Ϫ50 ЊC with a solution of 3 (80 mg, 0.27 mmol) in
diethyl ether (5 cm3) and under continuous stirring slowly
warmed to room temperature (1 h). To this solution, a solution
of Na[B(ArF)4] (102 mg, 0.12 mmol) in diethyl ether (10 cm3)
was added dropwise and the reaction mixture stirred for 45 min.
The solution was filtered, and the filtrate was brought to dry-
ness in vacuo. The residue was dissolved in CH2Cl2 (2 cm3) and
the solution was stored at Ϫ78 ЊC for 3 d. A pale-yellow micro-
crystalline solid precipitated, which was separated from the
mother liquor, washed twice with pentane (5 cm3) and dried.
Yield 135 mg (68%); mp 145 ЊC (decomp.); Λ = 45.6 cm2 ΩϪ1
molϪ1 (Found: C, 41.48; H, 4.26. C60H78As2BClF24P2Pd2
requires: C, 41.75; H, 4.55%). NMR (CD2Cl2): δH (400 MHz)
7.75 [8 H, s, br, ortho-H of B(ArF)4], 7.59 [4 H, s, br, para-H of
B(ArF)4], 2.70–2.58 (4 H, m, AsCHCH3 or PCHCH3), 2.55–
2.40, 2.07–1.87 (4 H each, both m, PCH2As and AsCHCH3 or
PCHCH3), 1.51–1.12 (48 H, m, AsCHCH3 and PCHCH3), 0.73
Reaction of 25 with AgBF4. A solution of 25 (90 mg,
0.19 mmol) in acetonitrile (5 cm3) was treated under continuous
stirring at Ϫ30 ЊC with a solution of AgBF4 (37 mg, 0.19 mmol)
in acetonitrile (5 cm3). An off-white solid precipitated. After
the solution was slowly warmed to room temperature, it was
stirred for 25 min. The solvent was then evaporated in vacuo,
the residue was suspended in dichloromethane (10 cm3) and the
suspension was filtered. The filtrate was brought to dryness
in vacuo, the remaining pale-yellow residue was washed three
1
[6 H, d, J(P,H) = 4.7, in H{31P} s, PdCH3]; δC (100.6 MHz)
162.1 [q, J(B,C) = 49.6, ipso-C of B(ArF)4], 135.1 [s, br, ortho-C
of B(ArF)4], 129.4 [qq, J(F,C) = 31.5, J(B,C) = 2.9, meta-C of
B(ArF)4], 124.9 [q, J(F,C) = 272.8, CF3], 117.8 [m, br, para-C
of B(ArF)4], 29.2 [d, J(P,C) = 21.0, PCHCH3], 28.9 (m, X-part
of ABX spin system, AsCHCH3), 24.8 (m, br, X part of ABX
spin system, AsCHCH3), 23.0, 21.1 (both s, AsCHCH3 or
PCHCH3), 20.6 [d, J(P,C) = 21.9, PCHCH3], 19.9, 19.6 [both d,
J(P,C) = 3.8, AsCHCH3 or PCHCH3], 19.7 (s, AsCHCH3 or
1
times with pentane (8 cm3) and dried. The H and 31P NMR
spectra revealed that besides 26 as the major species several
by-products were formed. Attempts to separate the by-products
2822
J. Chem. Soc., Dalton Trans., 2002, 2815–2824

View Article Online
Table 1 Crystallographic data for 4, 13 and 27
4
13
27
Formula
M
C15H34AsCl2PPd
497.61
C18H39AsF6P2Pd
612.75
C64H86As2BClF24P2Pd2
1782.24
Crystal system
Space group
a/Å
b/Å
c/Å
α/Њ
β/Њ
Monoclinic
P21/c (no. 14)
18.408(3)
8.1421(9)
14.335(2)
90
109.071(18)
90
2030.6(5)
173(2)
Monoclinic
P21 (no. 4)
9.0217(18)
17.072(3)
9.0882(18)
90
113.81(3)
90
1280.6(4)
173(2)
Triclinic
P1 (no. 2)
¯
14.487(9)
17.323(11)
17.554(12)
112.46(8)
96.69(8)
101.79(8)
3892(4)
γ/Њ
V/Å3
T /K
173(2)
Z
2
2
2
Dc/g cmϪ3
0.814
1.589
1.593
λ(Mo-Kα)/Å
0.71073
1.432
0.71073
2.177
0.71073
1.545
µ/mmϪ1
No. of reflections measured
No. of unique reflections
R1a
19820
3442 [R(int) = 0.0520]
0.0378
0.1001
0.904/Ϫ0.915
17768
6094 [R(int) = 0.0414]
0.0251
0.0620
1.014/Ϫ0.567
38138
12934 [R(int) = 0.0654]
0.0404
0.0928
0.063/Ϫ0.064
wR2b
Residual electron density/e ÅϪ3
2
2
a R = Σ|Fo Ϫ Fc|/ΣFo [for Fo > 2σ(Fo)] for the number of observed reflections [I > 2σ(I )], respectively. b wR2 = [Σw(Fo2 Ϫ Fc2)2/Σw(Fo )2]1/2; wϪ1 = [σ2(Fo )
ϩ (0.0691P)2 ϩ 0.0000P] 4, [σ2(Fo ) ϩ (0.0373P)2 ϩ 0.1233P] 13, [σ2(Fo ) ϩ (0.0409P)2 ϩ 0.0000P] 27, where P = (Fo2 ϩ 2Fc2)/3; for all data reflections,
2
2
respectively.
PCHCH3), 19.0 [d, J(P,C) = 1.9, AsCHCH3 or PCHCH3], 18.6
[d, J(P,C) = 3.8, AsCHCH3 or PCHCH3], 16.4 [d, J(P,C) = 5.7,
AsCHCH3 or PCHCH3], 10.4 (m, X part of ABX spin system,
PCH2As), Ϫ8.4 [d, J(P,C) = 3.8, PdCH3]; δC{H,P} (100.6 MHz)
162.1 [q, J(B,C) = 49.6, ipso-C of B(ArF)4], 135.1 [s, br, ortho-C
of B(ArF)4], 129.4 [q, br, J(F,C) = 31.5, meta-C of B(ArF)4],
124.9 [q, J(F,C) = 272.8, CF3], 117.8 [m, br, para-C of B(ArF)4],
29.5 (s, AsCHCH3 of minor isomer), 29.2 (s, PCHCH3 of
major isomer), 29.1 (s, PCHCH3 of minor isomer), 28.8, 24.8
(both s, AsCHCH3 of major isomer), 24.7 (s, AsCHCH3 of
minor isomer), 23.1 (s, AsCHCH3 or PCHCH3 of major iso-
mer), 21.9, 21.3 (both s, PCHCH3 of minor isomer), 21.1 (s,
AsCHCH3 or PCHCH3 of major isomer), 20.8, 20.1 (both s,
AsCHCH3 or PCHCH3 of minor isomer), 20.6 (s, PCHCH3 of
major isomer), 19.9, 19.65, 19.6 (all s, AsCHCH3 or PCHCH3
of major isomer), 19.5, 19.45, 19.4, 19.25 (all s, AsCHCH3 or
PCHCH3 of minor isomer), 18.9, 18.6 (both s, AsCHCH3
or PCHCH3 of major isomer), 17.3 (s, AsCHCH3 or PCHCH3
of minor isomer), 16.3 (s, AsCHCH3 or PCHCH3 of major
isomer), 10.7 [s, in 13C{1H} m, X part of ABX spin system,
PCH2As of minor isomer], 10.4 (s, PCH2As of major isomer),
Ϫ5.5 [s, in 13C{1H} m, PdCH3 cis to PiPr2 of minor isomer],
Ϫ8.4 (s, PdCH3 of major isomer), Ϫ11.7 [s, in 13C{1H} also s,
PdCH3 cis to AsiPr2 of minor isomer]; δF (376.4 MHz) Ϫ62.7 (s,
CF3); δP (162.0 MHz) 38.5 (s, major isomer), 30.6 (s, minor
isomer).
Four of the CF3-groups of the B(ArF)4 counterion in com-
pound 27 were found disordered and refined anisotropically
with restraints on Uij. One molecule of CH2Cl2 per unit formula
of 27 was located in the lattice.
CCDC reference number 182355 (13). The crystal structures
of 4 (143399) and 27 (143400) were reported previously.5
See http://www.rsc.org/suppdata/dt/b2/b202879b/ for crystal-
lographic data in CIF or other electronic format.
Acknowledgements
We thank the Deutsche Forschungsgemeinschaft (SFB 347)
and the Fonds der Chemischen Industrie for financial support,
the latter in particular for a Ph.D. grant (to K. I.). Moreover, we
are very grateful to Mrs M.-L. Schäfer and Dr R. Bertermann
(NMR measurements), Dr G. Lange and Mr F. Dadrich (mass
spectra), and to Mrs R. Schedl and Mr C. P. Kneis (elemental
analyses and DTA measurements).
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