Configurational selectivity in benzyldimethylarsine complexes of palladium(II) and platinum(II): Synthesis, spectroscopy and structures

Article abstract of DOI:10.1016/S0020-1693(02)01375-0

Benzyldimethylarsine complexes of palladium(II) and platinum(II) with the formulae [MX₂(BzAsMe₂)₂] (X=Cl, Br, I), [M₂Cl₂(μ-Cl)₂(BzAsMe₂) ₂], [Pd₂Cl₂(μ-OAc)₂(BzAsMe₂) ₂], [Pd₂Me₂(μ-Cl)₂(BzAsMe₂) ₂] and [Pd₂X₂(μ-N^{^}N)₂(BzAsMe ₂)₂] (M=Pd or Pt; N^{^}N=pyrazolate (pz) or 3,5-dimethylpyrazolate (dmpz)) have been prepared. All complexes have been characterised by elemental analysis, IR, UV-Vis absorption and NMR (¹H, ¹³C, ¹⁹⁵Pt) spectroscopy. The molecular structures of the complexes [MX₂(BzAsMe₂)₂] (M=Pt or Pd; X=Cl, Br or I) have been established by NMR spectroscopy and single crystal X-ray diffraction analysis and reveal a clear dichotomy in solution and in the solid between the compounds with X=Cl in a cis configuration and the trans configured bromide and iodide complexes.

Full text of DOI:10.1016/S0020-1693(02)01375-0

Inorganica Chimica Acta 346 (2003) 119Á128
/
www.elsevier.com/locate/ica
Configurational selectivity in benzyldimethylarsine complexes of
palladium(II) and platinum(II): synthesis, spectroscopy and
structures
Prasad P. Phadnis a, Vimal K. Jain a,*, Axel Klein b,*, Michael Weber b,
Wolfgang Kaim b
a Novel Materials and Structural Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
b Institut fur Anorganische Chemie, Universitat Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany
¨
¨
Received 22 July 2002; accepted 30 September 2002
Abstract
Benzyldimethylarsine complexes of palladium(II) and platinum(II) with the formulae [MX2(BzAsMe2)2] (Xꢀ
Cl)2(BzAsMe2)2], [Pd2Cl2(m-OAc)2(BzAsMe2)2], [Pd2Me2(m-Cl)2(BzAsMe2)2] and [Pd2X2(m-NfflN)2(BzAsMe2)2] (Mꢀ
NfflNꢀ
pyrazolate (pz) or 3,5-dimethylpyrazolate (dmpz)) have been prepared. All complexes have been characterised by elemental
analysis, IR, UVÁ
Vis absorption and NMR (1H, 13C, 195Pt) spectroscopy. The molecular structures of the complexes
[MX2(BzAsMe2)2] (MꢀPt or Pd; XꢀCl, Br or I) have been established by NMR spectroscopy and single crystal X-ray diffraction
analysis and reveal a clear dichotomy in solution and in the solid between the compounds with Xꢀ
/
Cl, Br, I), [M2Cl2(m-
/Pd or Pt;
/
/
/
/
/
Cl in a cis configuration and the
trans configured bromide and iodide complexes.
# 2002 Elsevier Science B.V. All rights reserved.
Keywords: Crystal structures; Platinum complexes; Palladium complexes; Arsine complexes
1. Introduction
The chemistry of organoarsenic compounds has
attracted considerable attention during the last decade
due to their applications in several chemical vapour
deposition (CVD) techniques for the preparation of
semiconductor materials [1,2]. In these techniques alkyl
derivatives show distinct advantages over the conven-
tional arsine (AsH3) source. The commercially available
The reactions of I with metal salts show a pronounced
dependence on the size of E. For example, N,N-
dimethylbenzylamine (I, ER2ꢀ
palladated when treated with Pd(OAc)2 or PdCl4
give binuclear complexes [Pd2(m-X)2(CfflN)2] (Xꢀ
OAc; CfflNꢀ
[7Á
metal salts readily yield complexes of the type
‘[M(PBznR3ꢁn)]’ [11Á15] and orthometallation reac-
/
NMe2) is readily cyclo-
2ꢁ
lower alkyls R3As (RꢀMe or Et) have high decom-
/
to
position temperatures and often yield poor quality films
[3]. Efforts are continuously made to develop alternative
clean and low decomposition temperature arsenic pre-
/Cl or
/cyclometallated dimethylbenzylamine)
/10]. In contrast, reactions of benzylphosphines with
cursors [4,5]. Benzylarsines (I; ER2ꢀAsMe2) may prove
/
successful precursors for CVD as the element (E)-benzyl
bond is split more easily than analogous methyl and aryl
linkages [6].
/
tions are often base promoted [16,17]. Benzylphosphines
are sterically more demanding and are stronger bases
than PPh3, consequently benzylphosphine complexes
have shown different reactivities [15]. In view of the
above and in pursuance of our work on organoarsenic
compounds it was considered worthwhile to explore the
* Corresponding authors.
E-mail addresses: jainvk@apsara.barc.ernet.in (V.K. Jain),
aklein@iac.uni-stuttgart.de (A. Klein).
0020-1693/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0020-1693(02)01375-0

120
P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á128
/
chemistry of palladium and platinum complexes of a
higher analogue, i.e. BzAsMe2, although several tertiary
arsine derivatives have been investigated earlier [18].
preparations also contained impurities of dibenzyl: d
2.96 (CH2); 7.16 (br, Ph)].
2.4.2. BzAsMe2
To a stirred ethereal solution (70 cm3) of CH3MgI
(17.43 g, 105 mmol) BzAsCl2 (10.3 g, 43.4 mmol) was
added dropwise with vigorous stirring under nitrogen at
0 8C. The reaction mixture was heated to reflux for 3 h
and then allowed to stand at r.t. To this a deoxygenated
aq. solution of NH4Cl (200 cm3) was added with
constant stirring and cooling at 0 8C till the magnesium
salts were completely dissolved in an aq. solution of
NH4Cl. The upper organic layer was separated and the
2. Experimental
2.1. Instrumentation
1
The H, 13C{1H} and 195Pt{1H} NMR spectra were
recorded on a Bruker DPX-300 spectrometer operating
at 300 (1H), 75.47 (13C) and 64.52 MHz (195Pt),
respectively. The chemical shifts are relative to internal
CHCl3 peak (dꢀ
/
7.26 ppm for 1H and dꢀ
/
77.0 ppm for
13C) and external Na2PtCl6 in D2O for 195Pt. IR spectra
were recorded as Nujol mulls using CsI plates on a
aq. layer was washed with Et2O (3ꢂ
were combined. The Et2O was distilled off and the
residue was distilled twice in vacuo (44Á45 8C/2 mmHg)
to yield a colourless liquid in 41% (3.5 g) yield. 1H NMR
/
50 cm3) and all
/
Bomen-102 FTIR spectrometer in the range of 200Á
/
4000 cmꢁ1. Microanalyses of the complexes were
carried out in the Analytical Chemistry Division of
Bhabha Atomic Research Centre.
in CDCl3: d 0.91 (s, AsMe2); 2.80 (s, AsCH2); 7.11Á7.30
/
(m, Ph). 13C{1H} in CDCl3: d 9.12 (s, AsMe2); 34.40 (s,
AsCH2); 125.0 (C-4); 128.1 (C-2, 6 or C-3, 5); 128.3 (C-
3, 5 or C-2, 6); 139.4 (s, C-1).
2.2. Crystallography
2.4.3. [PdCl2(BzAsMe2)2]
a
[PdCl2(MeCN)2] (1.948 g, 7.51 mmol), BzAsMe2 (2.95
g, 15.04 mmol) was added under a nitrogen atmosphere
with stirring which was continued for 3 h. The solvent
was evaporated in vacuo. The residue was recrystallised
For all six compounds [MX2(BzAsMe2)2] (Mꢀ
Pd; XꢀCl, Br, or I) data collection was performed at
Tꢀ173(2) K on a Siemens P4 diffractometer with MoÁ
Ka radiation (lꢀ
/
Pt or
To
stirred benzene solution (75 cm3) of
/
/
/
˚
/
0.71073 A) employing v Á2u scan
/
technique. The structures were solved using the
SHELXTL package [19] and refinement was carried out
with SHELXL-97 employing full-matrix least-squares
from CH2Cl2Áhexane mixture as yellow crystals in 80%
/
(3.44 g) yield. 13C{1H} NMR in CDCl3: d 6.0 (s,
AsMe2); 30.8 (s, AsCH2); 126.6 (C-4); 128.7 (C-2, 6 or
2
2
methods on F2 [20] with Fo ]
/
ꢁ
/
3s(Fo ) with the results
shown in Table 4. All non-hydrogen atoms were treated
anisotropically, hydrogen atoms were included by using
appropriate riding models.
C-3, 5); 129.4 (C-3, 5 or C-2, 6); 134.9 (C-1). UVÁVis
/
(CH2Cl2): lmax 364, 293 nm. Similarly [PtCl2(BzAs-
Me2)2] was prepared from [PtCl2(PhCN)2] (627 mg, 1.33
mmol) and BzAsMe2 (528 mg, 2.69 mmol) as white
2.3. Reagents and general procedures
crystals in 50% (435 mg) yield. UVÁVis (CH2Cl2): lmax
/
298, 272 nm.
[PdCl2(MeCN)2] or [PtCl2(PhCN)2] were prepared as
described in literature [21]. All reactions were carried
out under a nitrogen atmosphere in dry and distilled
analytical grade solvents.
2.4.4. [PdBr2(BzAsMe2)2]
To an acetone stirred solution (25 cm3) of
[PdCl2(BzAsMe2)2] (125 mg, 0.22 mmol) a large excess
of KBr (616 mg, 5.18 mmol) was added. It was stirred
for 3 days. The solvent was evaporated and the product
2.4. Synthesis
was recrystallised from acetoneÁ
yellowish crystals in 72% (104 mg) yield. UVÁ
(CH2Cl2): lmax 369, 286sh 255 nm. Similarly [PtBr2-
(BzAsMe2)2] was prepared from [PtCl2-
(BzAsMe2)2] (90 mg, 0.14 mmol) and a large excess of
KBr (736 mg, 6.18 mmol) as yellowish crystals in 61%
/
hexane mixture as
2.4.1. BzAsCl2
/
Vis
To a stirred Et2O solution of AsCl3 (36.3 g, 200
mmol) an ethereal solution of BzMgCl (36.2 g, 240
mmol) was added dropwise with vigorous stirring at
ꢁ78 8C over a period of 4 h. After warming to room
/
temperature (r.t.), stirring continued for an additional 2
h. The reaction mixture was filtered and the inorganic
(62 mg) yield. UVÁVis (CH2Cl2): lmax 300 nm.
/
salts were washed with Et2O (3ꢂ
was concentrated in vacuo and the residual oil was
distilled twice in vacuo (118Á120 8C/3 mmHg) as a faint
/
50 cm3). The filtrate
2.4.5. [PdI2(BzAsMe2)2]
To stirred acetone solution (30 cm3) of
[PdCl2(BzAsMe2)2] (126 mg, 0.22 mmol) a large excess
of KI (642 mg, 3.87 mmol) was added. The whole was
stirred for 2 days. The solvent was evaporated and the
/
1
greenish tinge liquid in 22% (10.3 g) yield. H NMR
spectrum in CDCl3: d 3.83 (s, CH2); 7.34 (m, Ph). [Some

P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á
/
128
121
product was recrystallised from acetoneÁ
ture as orange crystals in 70% (117 mg) yield. UVÁ
(CH2Cl2): lmax 420 (oꢀ
8240 Mꢁ1 cmꢁ1), 345sh (7800),
307 (26 010), 256 nm (24 770). Similarly [PtI2(B-
zAsMe2)2] was prepared from [PtCl2(BzAsMe2)2] (100
mg, 0.15 mmol) and a large excess of KI (598 mg, 3.60
/
hexane mix-
2.4.10. trans-[Pd2Cl2(m-dmpz)2(BzAsMe2)]
/Vis
To a stirred CH2Cl2 solution (25 cm3) of [Pd2Cl2(m-
OAc)2(BzAsMe2)] (68 mg, 0.086 mmol) a slight excess of
3,5-dimethylpyrazole (18 mg, 0.19 mmol) was added
under a nitrogen atmosphere and the whole was stirred
for 3 h. The solvent was evaporated under vacuum and
/
mmol) as orange crystals in 63% (80 mg) yield. UVÁ
(CH2Cl2): lmax 344 (oꢀ
6090 Mꢁ1 cmꢁ1), 288 nm (6900
Mꢁ1 cmꢁ1).
/
Vis
the residue was recrystallised from CH2Cl2Áhexane
mixture as pale yellow crystals in 70% (52 mg) yield.
13C{1H} in CDCl3: d 6.0, 7.9 (each s, AsMe2); 13.3, 13.6
/
/
(each s, Me2Ã
/
dmpz); 31.7 (s, AsCH2); 104.3 (s, dmpz C-
4); 126.9 (s, C-4); 128.8 (C-2, 6 or C-3, 5); 129.6 (s, C-3, 5
or C-2, 6); 134.7 (s, C-1) [Ph]; 147.2, 149.0 (each s, C-3, 5
dmpz).
2.4.6. [Pd2Cl2(m-Cl)2(BzAsMe2)2]
To a stirred benzene solution (50 cm3) of [PdCl2-
(BzAsMe2)2] (534 mg, 0.94 mmol), [PdCl2(MeCN)2] (235
mg, 0.91 mmol) was added and stirred for 1 h then
refluxed for 3 h. The solvent was evaporated and the
2.4.11. [Pd2Me2(m-dmpz)2(BzAsMe2)2]
To a stirred CH2Cl2 solution (30 cm3) of [Pd2Me(m-
Cl)2(BzAsMe2)2] (103 mg, 0.15 mmol) a slight excess of
methanolic solution (10 cm3) of dmpzH (30 mg, 0.31
mmol) containing aq. NaOH (0.66 cm3, 0.47 N, 12 mg,
0.30 mmol) was added under a nitrogen atmosphere.
The whole was stirred for 5 h and then filtered. The
solvent was evaporated in vacuo and the compound was
residue was recrystallised from benzeneÁhexane mixture
/
as orange red crystals in 71% (498 mg) yield. Similarly
[Pt2Cl2(m-Cl)2(BzAsMe2)2] was prepared from [PtCl2-
(BzAsMe2)2] (210 mg, 0.32 mmol) and PtCl2 (91 mg,
0.34 mmol), refluxing it in tetrachloroethane. The
residue was recrystallised from benzeneÁhexane mixture
in 34% (100 mg) yield.
/
recrystallised from CH2Cl2Á
coloured compound in 79% (95 mg) yield. 13C{1H} in
CDCl3: d ꢁ13.2 (s, PdMe); 7.0, 7.9 (each s, AsMe2);
13.7 (s, Me2Ãdmpz); 32.2 (s, AsCH2); 102.0 (s, C-4,
/hexane mixture as white
2.4.7. [Pd2Me2(m-Cl)2(BzAsMe2)2]
/
To an acetone solution (30 cm3) of [Pd2Cl2(m-
Cl)2(BzAsMe2)2] (253 mg, 0.34 mmol), a slight excess
of Me4Sn (130 mg, 0.73 mmol) was added under a
nitrogen atmosphere. Within a minute the colour faded.
The whole was stirred for 20 min. Then the solvent was
evaporated and the residue was washed with hexane to
remove Me3SnCl. The product was recrystallised from
/
dmpz); 126.3 (C-4); 128.5 (C-2, 6 or C-3, 5); 129.3 (C-3,
5 or C-2, 6); 135.8 (C-1) [Ph]; 145.4, 145.6 (each s, C-3, 5,
dmpz).
3. Results and discussion
acetoneÁhexane mixture as a cream crystalline solid in
/
66% (157 mg) yield.
3.1. Synthesis and spectroscopic analyses
2.4.8. [Pd2Cl2(m-OAc)2(BzAsMe2)2]
The syntheses of the palladium(II) and platinum(II)
complexes with benzyldimethylarsine are depicted in
Scheme 1 and their characterisation data are given in
To a stirred CH2Cl2 solution (25 cm3) of [Pd2Cl2(m-
Cl)2(BzAsMe2)2] (98 mg, 0.13 mmol), AgOAc (46 mg,
0.28 mmol) was added under a nitrogen atmosphere and
the whole was stirred for 4 h and the solvent was
evaporated and the product was recrystallised from
Tables 1 and 2. The reaction of [MCl2(RCN)2] (RꢀMe,
/
Ph) with 2 equiv. of BzAsMe2 readily gave [MCl2-
(BzAsMe2)2]. The chloride in the latter can be substi-
tuted with Br or I by treating it with an excess of KBr or
tolueneÁhexane mixture as red crystals in 54% (56 mg)
/
yield. 13C{1H} in CDCl3: d 6.6 (s, AsMe2); 23.4 (s, Me,
OAc); 31.9 (s, AsCH2); 127.2 (C-4); 129.0 (C-3, 5); 129.5
1
KI in acetone. The H NMR spectra exhibited singlets
each for the AsMe2 and AsCH2 protons which are
deshielded relative to the free ligand. The deshielding of
these resonances showed halogen dependence and
increases with increasing size of the halogen atom. The
signals for the platinum complexes were flanked by 195Pt
(C-2, 6); 133.4 (C-1) [Ph]; 182.2 (CÄ
/O).
2.4.9. [PdMe2(m-pz)2(BzAsMe2)]
To a stirred CH2Cl2 solution (30 cm3) of [Pd2Me2(m-
Cl)2(BzAsMe2)] (105 mg, 0.15 mmol), a methanolic
solution (10 cm3) of pyrazole (22 mg, 0.32 mmol)
containing aq. NaOH (0.65 cm3, 0.49 N, 13 mg, 0.32
mmol) was added under a nitrogen atmosphere. The
whole was stirred for 4 h and filtered. The solvent was
evaporated in vacuo and the residue was recrystallised
satellites. The 3J(PtÃ
approximately 17 Hz while the magnitude of J(PtÃ
associated with AsCH2 decreases with increasing the size
/
H) for the AsMe2 resonance is
3
/H)
3
of halogen atom J(PtÃ
/
H)ꢀ20 (Cl), 11 (Br), 7 (I) Hz).
/
The 195Pt NMR spectra display singlets (Table 2). The
195Pt NMR chemical shifts for [PtCl2(BzAsMe2)2] (d
from CH2Cl2Á
in 60% (69 mg) yield.
/
hexane mixture as a white cubic crystals
ꢁ
/
4320 ppm) can be compared with cis-[PtCl2(AsR3)2]
4363 ppm) [22,23]. The 195Pt
complexes (d ꢁ4287 to ꢁ
/
/

122
P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á128
/
Scheme 1. Preparation of the compounds (Mꢀ
/
Pt or Pd; Rꢀ
/
Me, Ph; pzꢀ
/
pyrazolate, dmpzꢀ3,5-dimethylpyrazolate).
/
NMR chemical shifts for the bromide (d ꢁ
and iodide (d ꢁ5496 ppm) are comparable to trans-
[PtX2(AsMe3)2] [XꢀBr (ꢁ4378), I (ꢁ5518)] [23] in-
dicative of a trans configuration for [PtX2(BzAsMe2)2]
(XꢀBr, I). Indeed, different configurations for XꢀCl
(cis) as opposed to XꢀBr or I (trans) were unambigu-
/
4359 ppm)
arsine can be purified by thermolysis of [PdCl2-
(BzAsMe2)2].
Since the phosphine and amine analogues of benzyl-
dimethylarsine easily undergo cyclometallation reac-
/
/
/
/
/
/
tions mainly in cases where Mꢀ
/
Pd [7,10Á17], the
/
/
present compounds were also examined in that respect.
For none of the six derivatives [MX2(BzAsMe2)2] did we
observe any metallation reaction during the preparation
of the compounds. To assess whether metallation of
BzAsMe2 is possible at all, the reactivity of [PdCl2-
(BzAsMe2)2] has been investigated in refluxing 2-ethox-
yethanol in the presence and absence of Na2CO3. In
both the cases, the starting material, as characterised by
m.p., analysis and 1H NMR, was recovered. The
reluctance to metallation of BzAsMe2 under these
reaction conditions indicates that there are only very
weak agostic interactions, if any, between the o-phenyl
proton and the vacant orbitals on palladium which is
usually the pre-requisite for the metallation reaction.
ously confirmed by X-ray structural analyses (vide
infra).
The compounds exhibit colours that range from deep
red to faint yellow in the solid as well as in fluid
solution. An investigation of the absorption spectra
revealed that the long-wavelength absorption maxima
are lower in energy for the palladium derivatives when
compared to the platinum analogues. Furthermore, the
energy decreases along the series Clꢀ
/
Brꢀ/I with the
exception that for MꢀPt the Br and Cl derivative
/
exhibit their long-wavelength maximum at approxi-
mately the same energy (Table 3). We tentatively assign
the long-wavelength absorptions to ligand(pX)-to-li-
gand(p*As) charge transfer transitions. This is supported
by recent investigations on related complexes of the type
The absence of intra- or intermolecular agostic MÁH
/
interactions was further substantiated by the X-ray
structural analyses of the complexes [MX2(BzAsMe2)2]
(vide infra).
The reaction of [MCl2(BzAsMe2)] with PtCl2 or
[PdCl2(MeCN)2] afforded the chloro-bridged complexes
[MCl(TeCH2CH2NMe2)(PR3)] (Mꢀ
/
Pt or Pd; Rꢀalkyl
/
or aryl) where the long-wavelength absorption were
assigned to ligand(Te)-to-ligand(P) charge transfer tran-
sitions [24]. Further support comes from the comparison
with related palladium complexes where in the series of
[M2Cl2(m-Cl)2(BzAsMe2)2] (Mꢀ
spectra displayed three MÃCl stretching bands at
approximately 342 [n MÃCl(terminal)], approximately
260 cmꢁ1 [n MÃ
Cl(bridging trans to arsine)], and 291 (Pd),
321 cmꢁ1 (Pt) [n MÃ
Cl(bridging trans to Cl)] [26,27]. The
195Pt NMR chemical shift for [Pt2Cl2(m-Cl)2(BzAsMe2)2]
(d ꢁ3015 ppm) is well in agreement with that of
[Pt2Cl2(m-Cl)2(AsMe3)2] (dꢀ 3034 ppm) [23]. The
/Pd or Pt). The IR
ER3 ligands (Eꢀ
maxima show a red-shift when going along the series
PBAsBSb [25].
/P, As, or Sb) the lowest absorption
/
/
/
/
/
We have reported earlier that tertiary arsines can be
purified by thermolysis of their palladium adducts [26].
To assess whether BzAsMe2 can be purified by thermo-
lysis, a thermogravimetric (TG) analysis of [PdCl2-
(BzAsMe2)2] was carried out under a flowing nitrogen
atmosphere. The TG curve shows that both arsine
molecules are liberated at approximately 200 8C (from
weight loss) leaving behind PdCl2. This suggests that the
/
/
/
ꢁ
/
reaction of [Pd2Cl2(m-Cl)2(BzAsMe2)2] with silver ace-
tate readily gave the acetato-bridged complex [Pd2Cl2(m-
OAc)2(BzAsMe2)2]. Treatment of [Pd2Cl2(m-Cl)2-
(BzAsMe2)2] with tetramethyltin in dichloromethane

P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á
/
128
123
Table 1
Physical, analytical and 1H NMR data for benzyldimethylarsine complexes of palladium(II) and platinum(II)
a
Complex
LꢀBzAsMe2
Recrystallisation
Solvent
Yield (%)
m.p.
(8C)
% Analysis
Found
(Calc.)
NMR data
(d in ppm)
IR
(cmꢁ1
/
)
[PdCl2(L)2]
CH2Cl2 Á/hexane (80) 156
C 37.5 (37.9)
H 4.2 (4.6)
1.24 (s, AsMe2)
3.38 (s, AsCH2Ph)
344
7.15Á
1.25 (s, 3J(PtÃ
3.35 (s, 3J(PtÃ
7.17Á
/
7.35 (m, AsCH2Ph)
[PtCl2(L)2]
CH2Cl2 Á/hexane (50) 169
C 32.2 (32.8)
H 3.8 (4.0)
/
H)ꢀ
/
17 Hz, AsMe2)
20 Hz, AsCH2Ph)
273
/H)ꢀ
/
/
7.32 (m, AsCH2Ph)
[PdBr2(L)2]
acetoneÁ
/
hexane (72) 153
hexane (61) 136
hexane (70) 140
hexane (63) 124
C 32.4 (32.8)
H 3.6 (4.0)
1.45 (s, AsMe2)
3.64 (s, AsCH2Ph)
7.21Á
1.33 (s, 3J(PtÃ
3.44 (s, 3J(PtÃ
7.16Á
/
7.32 (m, AsCH2Ph)
[PtBr2(L)2]
acetoneÁ
/
C 28.8 (28.9)
H 3.3 (3.5)
/H)ꢀ
/
17 Hz, AsMe2)
11 Hz, AsCH2Ph)
/H)ꢀ
/
/
7.36 (m, AsCH2Ph)
[PdI2(L)2]
acetoneÁ
/
C 28.3 (28.7)
H 3.3 (3.5)
1.58 (s, AsMe2)
3.64 (s, AsCH2Ph)
7.21Á
1.54 (s, 3J(PtÃ
3.60 (s, 3J(PtÃ
7.17Á
/
7.32 (m, AsCH2Ph)
[PtI2(L)2]
acetoneÁ
/
C 25.7 (25.7)
H 3.0 (3.1)
/H)ꢀ
/
18 Hz, AsMe2)
7 Hz, AsCH2Ph)
/H)ꢀ
/
/
7.35 (m, AsCH2Ph)
[Pd2Cl2(m-Cl)2(L)2]
[Pt2Cl2(m-Cl)2(L)2]
benzeneÁ
/
hexane (71) 213Á
/
216 C 28.0 (28.9)
H 2.8 (3.5)
1.34 (s, AsMe2)
3.58 (s, AsCH2Ph)
344
291
252
341
321
301
260
356
7.18Á
1.27 (s, 3J(PtÃ
3.45 (s, base broadened AsCH2Ph)
7.17Á7.36 (m, AsCH2Ph)
/
7.36 (m, AsCH2Ph)
benzeneÁ
/
hexane (34) 123Á
/
125 C 22.6 (23.4)
H 2.0 (2.8)
/H)ꢀ27 Hz; AsMe2)
/
/
b
[Pd2Cl2(m-OAc)2(L)2]
[Pd2Me2(m-Cl)2(L)2]
[Pd2Me2(m-pz)2(L)2]
tolueneÁ/hexane (54)
143Á
/
145 C 33.2 (33.3)
H 3.7 (4.0)
1.28 (s, AsMe2)
2.00 (s, PdÃOAc)
3.57 (s, AsCH2Ph)
7.18Á7.33 (m, AsCH2Ph)
/
/
acetoneÁ/hexane (66) 125
C 34.0 (34.0)
H 4.8 (4.6)
0.54 (s,PdMe)
1.18 (s, AsMe2)
3.25 (s, AsCH2Ph)
245
7.18Á
0.31 (s, PdÃ
(AB pattern 12.8 Hz AsCH2); 6.12 (s, CH, pz);
7.14Á7.33 (Ph, CH, pz); 7.44 (d, 1.5 Hz, CHÃpz)
/
7.35 (m, AsCH2Ph)
c
CH2Cl2 Á/hexane (60) 125
C 40.4 (40.6)
/
Me); 0.94, 1.10 (each s, AsMe2); 2.97
/
/
H 5.2 (5.0)
N 7.5 (7.3)
C 43.4 (43.7)
[Pd2Me2(m-dmpz)2(L)2] CH2Cl2 Á
/
hexane (79) 122Á
/
0.23 (s, PdÃ
2.24 (each s, Me2Ã
AsCH2); 5.57 (s, CH, dmpz); 7.08Á
/
Me); 0.89, 1.09 (each s, AsMe2); 1.98,
dmpz); 2.98 (AB pattern 12.8 Hz
7.33 (m, Ph)
c
123
/
/
H 6.4 (5.6)
N 6.6 (6.8)
[Pd2Cl2(m-dmpz)2(L)2] CH2Cl2 Á/hexane (70) 186Á/187 C 38.3 (38.8)
1.02, 1.27 (each s, AsMe2); 1.96, 2.34 (each s, Me2,
dmpz); 3.34 (AB pattern 12.8 Hz AsCH2); 5.58 (s,
CH, dmpz); 7.20Á7.33 (m, Ph)
/
H 4.9 (4.6)
N 6.3 (6.5)
a
b
c
n(MÃ
1562 cmꢁ1 (nCÄ
Decomposition occurs.
/
Cl).
/O).
afforded a binuclear methylpalladium complex [Pd2-
Me2(m-Cl)2(BzAsMe2)2]. The IR spectrum displayed a
Treatment of [Pd2Cl2(m-OAc)2(BzAsMe2)2] with 2
equiv. of 3,5-dimethylpyrazole gave [Pd2Cl2(m-dmpz)2-
(BzAsMe2)2]. The corresponding methylpalladium com-
plexes [Pd2Me2(m-NfflN)2(BzAsMe2)2] are obtained by
the reaction of [Pd2Me2(m-Cl)2(BzAsMe2)2] with pyra-
band at 245 cmꢁ1 attributable to bridging PdÃ
/Cl
1
stretchings. The H NMR spectrum showed a singlet
at 0.54 ppm due to PdÃMe protons.
/

124
P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á128
/
Table 2
195Pt{1H} NMR spectral data in CDCl3
142.38, respectively. Due to the short distances and the
appropriate angles the latter can be considered to be H
bridges of appreciable strength [29].
Complex
d
195Pt in ppm
The main difference in the molecular structures of the
examined compounds is the cis configuration of the
chloro derivatives that contrasts to the exclusive trans
configuration of the others (Figs. 1 and 2). This result is
unambiguous since it agrees with the observation by
NMR spectroscopy in fluid solution (vide supra). In the
trans derivatives, the two benzyl groups in the arsine
ligands are oriented towards each other in a staggered
fashion. In the two cis derivatives, the substituents on
the two arsine ligands are in an eclipsed orientation with
the benzyl substituents on the same positions. To
minimise the steric interaction one of the two benzyl
groups is located above the metal centre with the phenyl
ring like a shield to the metal. The other phenyl group is
tilted in the same direction giving rise to an asymmetry
in the molecule. Viewed from the chlorine atoms the
phenyl groups are tilted in an anti-clockwise fashion in
all molecules of both structures. Since the structures
were solved in the non-centrosymmetric space group
P21 we found only one of the two possible enantiomers.
The two cis forms show a very small deviation from the
ideal planar geometry surrounding the central atoms
with 4.0 (Pt) or 4.98 (Pd) dihedral angles between the
[PtCl2(BzAsMe2)2]
[PtBr2(BzAsMe2)2]
[PtI2(BzAsMe2)2]
ꢁ
/
4320
4359
5496
3015
ꢁ
/
ꢁ
/
[Pt2Cl2(m-Cl)2(BzAsMe2)2]
ꢁ/
zole or 3,5-dimethylpyrazole in the presence of metha-
1
nolic sodium hydroxide. The H and 13C NMR spectra
displayed only one C4Ã
/
H proton/carbon resonance
trans configuration [26,28]. The
indicative of a sym Á
/
two arsine ligands are anisochronous as two sets of
AsMe2 and an AB pattern for CH2As protons are
observed. Similarly 13C NMR spectra showed two
singlets for AsMe2 carbons.
3.2. Crystal structures of [MX2(BzAsMe2)2] (Mꢀ
/Pt
or Pd; XꢀCl, Br or I)
/
The molecular structures of all six compounds have
been obtained by single crystal X-ray diffraction with
the results summarised in Table 4. The two chloro
complexes were found to crystallise in the monoclinic
P21 space group whereas the structures of all other
derivatives were solved in P21/c. Looking at the crystal
structures three groups can be defined regarding their
intermolecular interactions. The three structures with
planes AsÃ
/
MÃ
/
As and ClÃ
/
MÃ/Cl. For the trans isomers,
the planes do not deviate significantly from planarity.
The bond lengths between the metal M and the halogens
decrease as expected along the series Iꢁ
MÃAs distances decrease along the same series, however
the difference between the palladium and platinum
complexes for XꢀBr or I are rather small. These
/
Brꢀ
/
Cl. The
/
Xꢀ
/
I; Mꢀ
/
Pd or Pt and Xꢀ
/
Br; MꢀPd exhibit short-
/
˚
est HÁ Á ÁX contacts of 3.22, 3.21 and 3.56 A, respectively.
/
The corresponding protons are the m-H atoms on the
findings agree well with the expected trans influence in
such square planar molecules. For the trans forms the
arsine ligands face each other in trans position, therefore
benzyl group. The angles CÃ
/
HÁ Á ÁX around 1458 are
reasonable for a H bridge, however, the long distances
exclude a substantial interaction [29]. The derivative
the MÃ
/
As distances are the same, only slightly influ-
with Mꢀ
/
Pt and XꢀBr shows the same interaction
/
˚
enced by the marginal cis influence. In the cis forms the
arsine face the much weaker chlorine ligands in trans
position, therefore their distance to the metal center is
much shorter. At the same time, the stronger trans
with XÁ Á ÁH contacts of 3.004 A (CÃ
/
HÁ Á ÁBrꢀ
/
1558), here
an additional interaction between Br and one proton of
˚
the methyl groups is observed. At 3.033 A these XÁ Á ÁH
contacts are slightly longer than the former but the angle
of 171.38 is better suitable for a H bridge [29]. Finally, in
the two chloro derivatives there are no interactions of
the Cl atoms with the m-H atoms of the phenyl ring but
appreciable contacts to the methyl groups of the
BzAsMe2 ligand. The ClÁ Á ÁH distances are 2.79 (Pt) or
influence exerted by the arsine ligands renders the MÃ
bonds longer than expected from the decreasing size of
the X atoms in the series IꢀBrꢀCl. The PtÃAs
distances are all longer than the one observed in
[PtMe{S2P(OPri)2}(AsPh3)] (PtÃ
The coordination around each arsine ligand is distorted
/
Cl
/
/
/
˚
/
Asꢀ2.3293(6) A) [30].
/
˚
2.76 A (Pd), respectively, and the angles are 140.5 and
Table 3
Long-wavelength absorption maxima for complexes [MX2(BzAsMe2)2] (Mꢀ
/
Pt or Pd; XꢀI, Br, or Cl) in CH2Cl2
/
Pd, I
Pd, Br
Pd, Cl
Pt, I
Pt, Br
Pt, Cl
l2 in nm (o in Mꢁ1 cmꢁ1
l1 in nm (o in Mꢁ1 cmꢁ1
)
)
307 (26 010)
420 (8240)
286sh
369
293
346
288 (6900)
344 (6090)
250sh
300
272
298

P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á
/
128
125
Table 4
Crystal data and refinement details for [MX2(BzAsMe2)2] (Mꢀ
/
Pt or Pd; Xꢀ/I, Br, or Cl)
IÃ/Pt
BrÃ
/
Pt
ClÃ
/
Pt
IÃPd
/
BrÃ/Pd
ClÃPd
/
Formula weight
Space group
Unit cell
841.12
P21/c
747.14
P21/c
658.22
P21
752.43
P21/c
658.45
P21/c
569.53
P21
˚
a (A)
11.696
8.3728
12.056
104.817
1141.4
2.447
11.524
8.1287
11.874
106.39
1067.1
2.325
9.9999
10.4762
10.1981
99.373
1054.1
2.074
11.656
8.3174
12.008
104.76
1125.8
2.220
11.585
8.1456
11.891
106.395
1076.5
2.031
10.0244
10.5075
10.2246
99.314
1062.8
1.780
˚
b (A)
˚
c (A)
b (8)
3)
˚
Volume (A
dcalc (mg mꢁ3
Absolute coefficient
)
11.727
13.394
10.022
6.481
7.622
4.211
(mmꢁ1
)
F(000)
768
696
624
704
632
560
Crystal size (mm)
0.3ꢂ
orange
3.00Á30.00
1Bh B16,
1Bk B11,
16Bl B16
Reflections collected 3642
/
0.3ꢂ
/
0.2
0.3ꢂ
yellow
3.08Á28.01
7Bh B15,
6Bk B10,
15Bl B15
2332
/
0.2ꢂ
/
0.1
0.3ꢂ
colourless
2.02Á28.00
0Bh B13,
0Bk B13,
13Bl B13
2818
/
0.2ꢂ
/
0.2
0.3ꢂ
deep red
1.81Á30.00
16Bh B
0Bk B11,
0Bl B16
3284
/
0.3ꢂ
/
0.2
0.3ꢂ
red
3.07Á
8B
3B
15B
3268
/
0.3ꢂ
/
0.1
0.2ꢂ
yellow
2.06Á30.00
7Bh B14,
14Bk B14,
14Bl B14
3413
/
0.2ꢂ
/
0.1
Colour
u Range (8)
Limiting indices
/
/
/
/
/
29.00
h B15,
k B11,
l B16
/
ꢁ
/
/
/
ꢁ
/
/
/
/
/
ꢁ/
/
/
15,
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ
/
/
/
/
/
/
/
ꢁ
/
/
/
ꢁ
/
/
/
ꢁ/
/
/
ꢁ/
/
/
ꢁ/
/
/
/
/
ꢁ/
/
/
ꢁ/
/
/
Independent (Rint
Data/restraints/
parameters
)
2900 (0.0509)
2900/0/105
2219 (0.0293)
2219/0/106
2675 (0.0516)
2675/1/210
3284 (0.0389)
3284/0/106
2593 (0.0402)
2593/0/105
3083 (0.0788)
3083/1/207
Final R indices
R1ꢀ
wR2ꢀ
R1ꢀ0.0514,
wR2ꢀ0.0931
1.053
/
0.0376,
R1ꢀ
wR2ꢀ
R1ꢀ0.0375,
wR2ꢀ0.0794
1.150
/
0.0305,
R1ꢀ
wR2ꢀ
R1ꢀ0.0518,
wR2ꢀ0.0861
1.028
/
0.0378,
R1ꢀ
wR2ꢀ
R1ꢀ0.0668,
wR2ꢀ0.1593
1.165
/
0.0581,
R1ꢀ
wR2ꢀ
R1ꢀ0.0508,
wR2ꢀ0.0912
1.038
/
0.0367,
R1ꢀ
wR2ꢀ
R1ꢀ0.0492,
wR2ꢀ0.1064
1.032
/
0.0412,
/0.0868
/0.0760
/
0.0807
/
0.1593
/0.0855
/0.1013
R indices (all data)
/
/
/
/
/
/
/
/
/
/
/
/
Goodness-of-fit
on F2
Largest difference
˚
peak and hole (e A
1.788 and ꢁ
/
1.818 1.232 and ꢁ
/
0.926 1.600 and ꢁ
/
1.194 2.482 and ꢁ
/
2.962 0.797 and ꢁ
/
1.322 1.869 and ꢁ1.570
/
ꢁ3
)
˚
Empirical formulae: C18H26As2X2M; measurement temperature: 173(2) K; wavelength 0.71073 A; absorption correction: empirical by c-scans,
only for [PdI2(BzAsMe2)2] empirical correction using XABS2 [33]; refinement method: full-matrix least-squares on F2.
Fig. 1. Molecular structures of trans-[PtI2(BzAsMe2)2] (left) and cis-[PtCl2(BzAsMe2)2] (right) with atom numbering. Shown were the thermal
ellipsoids at a 50% probability level.

126
P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á128
/
Fig. 2. Molecular structures of trans-[PdBr2(BzAsMe2)2] (top) and cis-[PdCl2(BzAsMe2)2] (bottom) with atom numbering. Shown were the thermal
ellipsoids at a 50% probability level.
tetrahedral since the C(1)Ã
compared to the ideal tetrahedral angle to values of
around 1138 while the H3CÃAsÃCH3 angles have been
compressed to values in the range 100.8Á102.08 for the
trans conformers. For the cis forms the first deviation is
smaller but the latter is larger when compared to the
/
AsÃ
/
M angles are opened
compounds has been created. However, in none of the
examined compounds did the benzylarsine ligand un-
dergo cyclometallation as is often observed for the
analogous phosphines or amines. This is not totally
unexpected since an increasing reluctance towards
cyclometallation has been observed when going from
the amines to the phosphines. In many cases it is not
even possible to prevent that reaction, for the amines it
is promoted by interaction between the o-H on the
phenyl substituent and the metal center whereas an
activation by bases is required in case of the phosphines.
The present arsine systems terminates the series in that
sense: we could not observe any metallation reactivity,
not even for the reactive palladium systems. Strong
support also comes from the fact that we do not have
/
/
/
trans isomers. From the MÃ
/
X and MÃ
/
As distances for
XꢀBr or Cl it seems that the palladium atom is bigger
/
than the platinum atom. This was also found in recent
structural work on amido complexes of Pt, Pd and Ni
[31] and on a series of heterocubane compounds
[Cp3Mo3S4M(PPh3)] with MꢀPt or Pd [32]. This effect
/
is explained by the classical ‘lanthanide contraction’ and
also by relativistic effects. However, in our series for
XꢀI the distances show the reverse trend. We assume
/
that this is due to the fact that the ionic radii increase
much more on going from Br (196 pm) to I (220 pm)
than from Cl (184 pm) to Br which might compensate
for the reduced size of platinum (Table 5).
any evidence for a metalÁH interaction, neither from
/
NMR spectroscopy in solution nor from X-ray structure
analyses of the complexes [MX2(BzAsMe2)2] in the solid
state. The structure analysis has revealed some weak
HÁ Á ÁX interactions for the two cis configured complexes
with XꢀCl. However, the interaction occurs between
/
4. Conclusions
Cl and one methyl substituent of the arsine ligand. A
similar interaction was found in the bromo platinum
complex although the latter has a trans configuration
The presented series of palladium and platinum
complexes containing the benzyldimethylarsine ligands
has revealed some interesting aspects concerning their
structures and reactivity. Starting from the simple
chloro complexes [MCl2(BzAsMe2)2] a wealth of new
like the three residual derivatives (Xꢀ
Pd and XꢀBr with MꢀPd). It is remarkable that these
strictly dichotomous configurations, cis for XꢀCl and
trans for XꢀBr or I, are also found by NMR spectro-
/
I with Mꢀ/Pt or
/
/
/
/

P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á
/
128
127
Table 5
Selected bond lengths (A) and angles (8) for [MX2(BzAsMe2)2]
˚
Mꢀ/Pt
Mꢀ/Pd
Mꢀ/Pt
Mꢀ/Pd
Mꢀ
/
Pt
Mꢀ/Pd
Xꢀ/I
Xꢀ
/
I
XꢀBr
/
XꢀBr
/
XꢀCl
/
XꢀCl
/
Bond lengths
MÃ
MÃ
MÃ
MÃ
AsÃ
AsÃ
AsÃ
AsÃ
AsÃ
AsÃ
/
X(1)
X(2)
As(1)
As(2)
2.6169(6)
2.4118(8)
1.981(7)
1.940(6)
1.948(7)
2.5981(6)
2.4080(7)
1.976(7)
1.939(7)
1.929(7)
2.4384(7)
2.3898(8)
1.969(6)
1.929(6)
1.927(6)
2.4417(6)
2.4048(6)
1.970(4)
1.935(4)
1.935(4)
2.340(3)
2.355(3)
2.370(2)
2.359(2)
2.3524(9)
2.3586(9)
1.977(9)
1.959(7)
1.923(7)
1.940(9)
1.925(10)
1.950(9)
/
/
2.3371(14)
2.3343(13)
1.937(14)
1.984(13)
1.935(14)
1.925(14)
1.918(14)
1.932(14)
/
/
C(1)
/
C(11)
C(8)
/
/
C(18)
C(9)
/
/
C(19)
Bond angles
X(1)ÃMÃX(1A)
As(1)ÃMÃAs(1A)
X(1)ÃMÃ
X(2)ÃMÃ
X(1)ÃMÃ
X(2)ÃMÃ
MÃAs(1)Ã
MÃAs(2)Ã
H3CÃAsÃ
H3CÃAsÃ
a
/
/
180.000(8)
180.000(8)
92.42(2)
180.000(19)
180.000(19)
92.43(2)
180.00(3)
180.00(3)
92.76(2)
180.000(10)
180.000(10)
92.794(19)
90.05(12)
100.74(5)
173.15(10)
174.84(9)
84.39(9)
92.43(7)
99.19(3)
174.03(7)
176.59(6)
84.28(6)
84.16(5)
107.6(2)
110.0(3)
101.7(4)
99.7(4)
a
/
/
/
/
As(1)
As(2)
As(1A)
As(1)
/
/
a
/
/
87.58(2)
113.1(2)
101.4(4)
87.57(2)
113.49(17)
100.8(3)
87.24(2)
112.82(17)
101.7(3)
87.206(19)
112.65(12)
102.0(2)
/
/
84.88(10)
107.7(4)
/
/
C(1)
/
/
C(11)
109.9(4)
/
/
CH3
100.9(7)
/
/
CH3
102.3(7)
a
For cis configuration X(1)Ã
/
MÃ
/
X(2), As(1)Ã
/
MÃ
/
As(2) and X(1)Ã
/
MÃAs(2) are given.
/
scopy in solution indicating an unusually strong struc-
tural selectivity.
thank Drs. J.P. Mittal and P. Raj for their encourage-
ment of this work. The facilities provided by the
Analytical Chemistry Division, BARC for microanalysis
are gratefully acknowledged. Support for this work
under the Indo-German Bilateral Agreement from
BMBF (Project No. 99/060) is similarly acknowledged.
5. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 193965 (Mꢀ
193966 (MꢀPt, XꢀBr), 193967 (MꢀPt, Xꢀ
193968 (MꢀPd, XꢀI), 193969 (MꢀPd, XꢀBr), and
193970 (MꢀPd, XꢀCl). Copies of this information
may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
/
Pt, Xꢀ
/
I),
References
/
/
/
/
Cl),
/
/
/
/
[1] D.W. Bruce, D.O. Hare, Inorganic Materials, Wiley, New York,
1992, p. 491.
/
/
[2] M.L. Hitchman, K.F. Jensen, Chemical Vapour Deposition,
Principles and Applications, Academic Press, London, 1993, p.
245.
(fax: (int code) ꢃ44-1223-336-033; e-mail: deposit@
/
[3] R.M. Lum, J.K. Klingert, M.G. Lamont, J. Cryst. Growth 89
(1988) 137.
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
[4] A. Brauers, J. Cryst. Growth 107 (1991) 281.
[5] R.M. Lum, J.K. Klingert, J. Cryst. Growth 107 (1991) 290.
[6] (a) J.Y.C. Chu, D.G. Marsh, W.H.H. Gunther, J. Am. Chem.
Soc. 97 (1995) 4905;
5.1. Further supplementary material
Six figures illustrating the crystal structures (unit cell
and intermolecular interaction) and full structural data
of all six complexes (30 tables) are available from the
author on request.
(b) H.K. Spencer, M.V. Lakoshmikanthan, M.P. Cava, J. Am.
Chem. Soc. 99 (1977) 1470.
[7] A.C. Cope, E.C. Friedrich, J. Am. Chem. Soc. 90 (1968) 909.
[8] T.C. Jones, A.J. Nielson, C.E. Richard, Aust. J. Chem. 37 (1984)
2179.
[9] A.D. Ryabov, I.K. Sakodinskaya, A.K. Vatsimirsky, J. Chem.
Soc., Dalton Trans. (1985) 2629.
[10] M. Pfeffer, Inorg. Synth. 26 (1989) 211.
[11] A.W. Verstuyft, A.D. Redfield, L.W. Cary, J.H. Nelson, Inorg.
Chem. 16 (1977) 2776.
Acknowledgements
One of the authors (P.P.P.) is grateful to DAE for the
award of a Senior Research Fellowship. The authors
[12] (a) B. Bendiksen, W.C. Riley, M.W. Babich, J.H. Nelson, R.A.
Jacobson, Inorg. Chim. Acta 57 (1982) 29;

128
P.P. Phadnis et al. / Inorganica Chimica Acta 346 (2003) 119Á128
/
(b) N.W. Alcock, J.H. Nelson, Acta Crystallogr., B 38 (1982)
2463.
[23] P.L. Goggin, R.J. Goodfellow, S.R. Haddock, B.F. Taylor,
I.R.H. Marshall, J. Chem. Soc., Dalton Trans. (1976) 459.
[24] S. Dey, V.K. Jain, A. Knodler, A. Klein, W. Kaim, S. Zalis,
¨
[13] L.M. Wilkes, J.H. Nelson, J.P. Mitchner, M.W. Babich, W.C.
Riley, B.J. Helland, R.A. Jacobson, M.Y. Cheng, K. Seff, L.B.
McCusker, Inorg. Chem. 21 (1982) 1376.
Inorg. Chem. 41 (2002) 2864.
[25] A.T. Hutton, C.P. Morley, in: G. Wilkinson, R.D. Gilliard, J.A.
McCleverty (Eds.), Comprehensive Coordination Chemistry, vol.
5 (and references therein), Pergamon Press, New York, 1987.
[26] P.P. Phadnis, V.K. Jain, A. Knoedler, W. Kaim, Z. Anorg. Allg.
Chem. 628 (2002) 1332.
[14] H.P. Abicht, K. Jurkschat, Z. Chem. 28 (1988) 371.
[15] E.W. Ainscough, A.M. Brodie, A.K. Burrell, G.H. Freeman, G.B.
Jameson, G.A. Bowmaker, J.V. Hanna, P.C. Healy, J. Chem.
Soc., Dalton Trans. (2001) 144.
[16] (a) H.P. Abicht, K. Issleib, Z. Anorg. Allg. Chem. 447 (1978) 53;
(b) H.P. Abicht, K. Issleib, J. Organomet. Chem. 149 (1978) 209.
[17] H.P. Abicht, K. Issleib, Z. Anorg. Allg. Chem. 500 (1983) 31.
[18] C.A. McAuliffe, W. Levason, Phosphine, Arsine and Stibine
Complexes of the Transition Elements, Elsevier, New York, 1979.
[19] G.M. Sheldrick, SHELXTL, Bruker Analytical X-ray Systems,
Madison, WI, USA, 1998.
[27] R.J. Goodfellow, P.L. Goggin, L.H. Venanzi, J. Chem. Soc., Sect.
A (1967) 1897.
[28] A. Singhal, V.K. Jain, J. Chem. Soc., Dalton Trans. (1993) 1515.
[29] T. Steiner, Angew. Chem., Int. Ed. Engl. 41 (2002) 48 (and
references therein).
[30] V.K. Jain, S. Chaudhury, A. Vyas, R. Bohra, J. Chem. Soc.,
Dalton Trans. (1994) 1207.
[20] G.M. Sheldrick, SHELXL-97: A Program for Crystal Structure
Determination, Universitat Gottingen, Gottingen, Germany,
1997.
[31] J.C. Peters, S.B. Harkins, S.D. Brown, M.W. Day, Inorg. Chem.
40 (2001) 5083.
¨
¨
¨
[32] K. Herbst, B. Rink, L. Dahlenburg, M. Brorson, Organometallics
20 (2001) 3655.
[21] F.R. Hartley, The Chemistry of Platinum and Palladium, Applied
Science, London, 1973.
[22] P.S. Pregosin, Coord. Chem. Rev. 44 (1982) 247.
[33] S. Parkin, B. Moezzi, H. Hope, XABS2: J. Appl. Crystallogr. 28
(1995) 53.