Preparation and characterization of dinuclear Pd(II) complexes of binucleating tetraaza-thiophenolate ligands

Article abstract of DOI:10.1039/b516071e

The thioethers 4-tert-butyl-2,6-bis((2-(dimethylamino)ethylimino)methyl) phenyl(tert-butyl)sulfane (tBu-L³) and 4-tert-butyl-2,6-bis((2- (dimethylamino)ethylimino)methyl)phenyl(tert-butyl)sulfane (tBu-L⁴) react with PdCl₂(

Full text of DOI:10.1039/b516071e

View Article Online / Journal Homepage / Table of Contents for this issue
PAPER
www.rsc.org/dalton | Dalton Transactions
Preparation and characterization of dinuclear Pd(II) complexes of
binucleating tetraaza-thiophenolate ligands
Gabriel Siedle and Berthold Kersting*
Received 11th November 2005, Accepted 17th January 2006
First published as an Advance Article on the web 7th February 2006
DOI: 10.1039/b516071e
The thioethers 4-tert-butyl-2,6-bis((2-(dimethylamino)ethylimino)methyl)phenyl(tert-butyl)sulfane
(tBu–L3) and 4-tert-butyl-2,6-bis((2-(dimethylamino)ethylimino)methyl)phenyl(tert-butyl)sulfane
(tBu–L4) react with PdCl2(NCMe)2 to give the dinuclear palladium thiophenolate complexes
[(L3)Pd2Cl2]+ (2) and [(L4)Pd2(l-Cl)]2+ (3) (HL3 = 2,6-bis((2-(dimethylamino)ethylimino)methyl)-4-
tert-butylbenzenethiol, HL4 = 2,6-bis((2-(dimethylamino)ethylamino)methyl)-4-tert-butyl-
benzenethiol). The chloride ligands in 2 could be replaced by neutral (NCMe) and anionic ligands
(NCS−, N3−, CN−, OAc−) to give the diamagnetic PdII complexes [(L3)Pd2(NCMe)2]3+ (4),
[(L3)Pd2(NCS)2]+ (5), [(L3)Pd2(N3)2]+ (6), [{(L3)Pd2(l-CN)}2]4+ (7) and [(L3)Pd2(OAc)]2+ (9). The nitrile
ligands in 4 and in [(L3)Pd2(NCCH2Cl)2]3+ are readily hydrated to give the corresponding amidato
complexes [(L3)Pd2(CH3CONH)]2+ (8) and [(L3)Pd2(CH2ClCONH)]2+ (10). The reaction of
[(L3)Pd2(NCMe)2]3+ with NaBPh4 gave the diphenyl complex [(L3)Pd2(Ph)2]+ (11). All complexes were
either isolated as perchlorate or tetraphenylborate salts and studied by IR, 1H and 13C NMR
spectroscopy. In addition, complexes 2[ClO4], 3[ClO4]2, 5[BPh4], 6[BPh4], 7[ClO4]4, 9[ClO4]2, 10[ClO4]2
and 11[BPh4] have been characterized by X-ray crystallography.
Introduction
The coordination chemistry of binucleating thiophenolate ligands
has been actively pursued in the past several years.1–4 Motivations
in this area are diverse and include the preparation of model
compounds for dinuclear metallo enzymes,5 the stabilization of un-
usual metal oxidation states,6 and attempts to understand, achieve
and control binuclear metal reactivity,7–9 to name a few. Traditional
routes to such complexes make use of the free thiophenols, but
their synthetic procedures are often time-consuming and tedious,
thereby hampering a more rapid exploitation of this research area.
With this in mind several groups are currently involved in the
development of alternative synthetic strategies which provide more
direct access to binucleating thiophenolate ligand systems.10,11
Among many procedures in the literature, the metal-ion-promoted
S-deprotection of arylthioesters12 or arylthioethers13 has turned
out to be a very convenient and efficient one.
Scheme 1 Structures of L1 and [(L2)Pd2Cl2]+ and of the thioethers tBu–L3
and tBu–L4 used in the synthesis of dinuclear palladium(II) complexes.
Recently we found that the macrobicyclic hexaazadithioether L1
undergoes a S–C bond cleavage reaction in the presence of
PdCl2(NCMe)2 to afford the dinuclear complex [(L2)Pd2Cl2]+ of
the ring-opened hexaaza-vinylthioether/thiophenolate derivative
(L2)− (Scheme 1).14 This led us to investigate the possibility of
synthesizing related palladium thiophenolate complexes by using
the open-chain thioethers tBu–L3 and tBu–L4 as starting materials.
Herein we report on the reactions of these two thioethers with
PdCl2(NCMe)2 and describe the coordination chemistry of the
new dinuclear palladium thiophenolate complexes formed.
Results and discussion
Synthesis of proligands and complexes
Scheme 2shows the preparationofthe proligands tBu–L3 and tBu–
L4 and the complexes 2–7. The imine-amine-thioether tBu–L3 was
prepared in nearly quantitative yield by a Schiff-base condensation
reaction between dialdehyde 115 and Nꢀ,Nꢀ-dimethylethane-1,2-
diamine. The subsequent sodium-borohydride reduction of tBu–
L3 gave the tetraamine-thioether tBu–L4. Unlike its parent tBu–
L3, the tetraamine-thioether tBu–L4 could not be obtained in
analytically pure form. Nonetheless it was of sufficient purity
for metal complex syntheses. Treatment of tBu–L3 with two
equivalents of PdCl2(NCMe)2 in acetonitrile solution at ambient
temperature for 2 days gave a yellow solution, from which
upon addition of an excess of LiClO4 yellow crystals of 2[ClO4]
Institut fu¨r Anorganische Chemie, Universita¨t Leipzig, Johannisallee
29, D-04103, Leipzig, (Germany). E-mail: b.kersting@uni-leipzig.de;
Fax: +49/(0)341-97-36199
2114 | Dalton Trans., 2006, 2114–2126
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
Scheme 2 Synthesis of proligands tBu–L3 and tBu–L4 and complexes 2–7.
precipitated in ca. 70% yield. Similarly, reaction of tetraamine-
thioether tBu–L4 with two equivalents of PdCl2(MeCN)2 in a
mixed acetonitrile–dichloromethane solvent system at ambient
temperature for 12 h gave a yellow solution, from which upon addi-
tion of an excess of LiClO4 a compound of composition [(L4)Pd2(l-
Cl)][ClO4]2 (3[ClO4]2) precipitated in ca. 77% yield. Thus, as was
observed previously for the macrobicyclic compound L1,14 the two
thioethers undergo a Pd-promoted S–C bond cleavage reaction
to generate dinuclear palladium complexes of the binucleating
thiophenolate ligand (L3)− and (L4)−, respectively.
Dinuclear palladium complexes of binucleating thiolate lig-
ands such as those reported by McKenzie and Robson,16,24 are
known to exhibit a rich coordination chemistry as the terminal
chloride ligands can be readily exchanged for other neutral or
anionic species. These observations dictated that complex 2 would
display a similar rich coordination chemistry. In the following
we will show that this is the case. The bisacetonitrile derivative
[(L3)Pd2(NCMe)2]3+ (4) was selected as the first target compound.
This complex was obtained by Cl− abstraction from [(L3)Pd2Cl2]+
(2) with anhydrous Pb(ClO4)2 and isolated as its triperchlorate
salt in 76% yield. Treatment of this material with 2 equivalents
of NaSCN at ambient temperature resulted in the formation
of a red solution from which an orange-colored product of
composition [(L3)Pd2(SCN)2][ClO4] (5[ClO4]) could be isolated in
53% yield. The reaction of 4[ClO4]3 with two equivalents of sodium
azide in a mixed acetone–methanol solvent system produced
the azido complex [(L3)Pd2(N3)2]+ (6), which was isolated as its
perchlorate in 81% yield. Complexes 5 and 6 were also isolated
as their tetraphenylborate salts. When complex 2 was treated with
Pb(ClO4)2 in propionitrile as the solvent a tetranuclear cyanide
complex [{(L3)Pd2(l1,2-CN)}2][ClO4]4 (7[ClO4]4) was obtained in
high yields. The cyanide ions are presumably generated via a Pb2+-
mediated retro-hydrocyanation of the solvent (CH3CH2CN →
=
CH2 CH2 + HCN). This is supported by the fact that propio-
nitrile solutions of Pb(ClO4)2 develop ethylene gas and HCN
which can be detected by gas chromatography. It can be ruled
out that the cyanide ions stem from an HCN impurity in the
solvent, because this was carefully purified (washing with K2CO3
and KMnO4 solution) and freshly distilled from appropriate
drying agents. Likewise, the fact that there is no detectable
=
CH2 CH2 in the gas phase above a propionitrile solution of
the palladium complex 4[ClO4]3 rules out the possibility that
the retro-hydrocyanation is catalyzed by the palladium thiolate
complexes.
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 2114–2126 | 2115
©

View Article Online
Table 1 Selected IR spectroscopic data (cm−1) for compounds tBu–L3,
2[ClO4] and 8[ClO4]2–10[ClO4]2
In the course of this work it was found that the Pd-bound
acetonitriles in 4 are readily hydrated to acetamide. Thus, the re-
action of 4 with water proceeded smoothly to give the MeCONH−
complex [(L3)Pd2(NHCOMe)]2+ (8) which could be isolated as
its perchlorate salt (8[ClO4]2) in ca. 60% yield (Scheme 3). The
acetato-bridged compound [(L3)Pd2(OAc)][ClO4]2 (9[ClO4]2) was
prepared for comparative purposes. Unfortunately, we have not
been able to grow single crystals of 8[ClO4]2 suitable for an X-
ray crystal structure determination. On these grounds we chose to
investigate the hydration of 2-chloroacetonitrile. As indicated in
Scheme 3, the trication [(L3)Pd2(NCCH2Cl)2]3+ (prepared in situ
from 2[ClO4]2 and Pb(ClO4)2 in neat 2-chloroacetonitrile) is also
readily hydrated by aqueous methanol to give the corresponding
2-chloroacetamido complex [(L3)Pd2(NHOCCH2Cl)]2+ (10). Note
that the chloro-function is not hydrolyzed under these conditions.
=
m(C N)
mas, ms(RCO2)
mas, ms(RCONH)
m(N–H)
tBu–L3
2[ClO4]
8[ClO4]2
1632
1637
1648
1628
1643
1649
1630
1553, 1436
3316
3308
9[ClO4]2
10[ClO4]2
1555, 1437
1573, 1414
Spectroscopic characterization of proligands and complexes
The most significant feature in the IR spectrum of crystalline tBu–
L3 is the strong band at 1632 cm−1, which can be readily assigned
1
The dipalladium(II) complex [(L3)Pd2(g -Ph)2][BPh4] (11[BPh4])
to the C N stretching frequency of the imine functions due to its
=
bearing two phenyl groups represents the last complex of this study.
Complex 11 formed as a side product in the salt metathesis reaction
between 4[ClO4]3 and NaBPh4 in a mixed ethanol–acetonitrile (1 :
1) solvent system (Scheme 3). The ability of the tetraphenylborate
absence in the IR of its reduced derivative tBu–L4 (Table 1). The IR
spectrum of 4[ClO4]3 shows intense absorption bands at 2330 and
2303 cm−1 attributable to the C≡N stretching frequencies of the
Pd-bound acetonitriles. Free acetonitrile absorbs at much lower
frequencies (m(C≡N) ∼ 2250 cm−1), indicative of a polarisation
of the carbon nitrogen triple bond in 4.19 A strong IR band
at 2108 cm−1 in the IR spectrum of 5[ClO4] was indicative of
the coordination of thiocyanate ions.20 In agreement with the
formulation of 6[ClO4] the IR spectrum displays strong bands at
2030 and 2017 cm−1 for the azide groups mas(N3−) and at 1100 cm−1
−
to transfer a C6H5 unit to cationic Pd(II) complexes has been
reported previously,17 but to the best of our knowledge a double
C6H5−-transfer to a dinuclear Pd2 complex is unprecedented.
◦
Complex 11[BPh4] is stable toward heat (mp >140 C decomp.),
moisture and air. This stability is unusual compared to the lower
stability of mononuclear Pd–Ph complexes.18 The presence of the
adjacent phenyl rings might be expected to encourage the reductive
elimination of biphenyl from the binuclear palladium complex,
and yet this compound is stable indefinitely.
for the ClO4 anion. The bridging CN− groups in 7[ClO4]4
−
are readily identified by the strong m(CN) band at 2184 cm−1.
Monodentate cyanides absorb at much lower wavenumbers.21 The
IR spectrum of 8 contrasts that of 9 in that it exhibits an additional
band at 3316 cm−1 for the N–H stretching vibration. Similar values
are observed for 10[ClO4]2 and other acetamido complexes.22
Selected 1H and 13C NMR data for the compounds are presented
in Table 2. The 1H NMR spectrum of tBu–L3 in CDCl3 solution
shows in accordance with its structure singlets for the two tert-
butyl groups (d 1.06 and 1.26 ppm), the methyl protons of the four
NCH3 groups (d 2.21 ppm), the aromatic protons (d 8.07 ppm) and
the two imine protons (d 9.08 ppm). The methylene protons give
rise to two triplets centred at d 2.55 and 3.68 ppm. The 13C NMR
spectrum of tBu–L3 displays seven aliphatic, one imine and four
aromatic 13C signals. Conversion of the two imine groups of tBu–L3
to secondary amine functions in tBu–L4 is supported by the ab-
=
sence of the signal for the imine protons (CH N) and the presence
of a new signal at d 2.62 ppm for the benzylic methylene protons.
1
The H NMR signal for the tert-butyl group of the thioether
moiety of tBu–L3 at d 1.06 ppm is absent in the 1H NMR spectrum
of 2. Likewise, the 13C NMR spectrum revealed only the 13C signals
(d 30.6, 35.7) for the tert-butyl group bonded to the aromatic
carbon atom C10 (for atom labels see inset Table 2). It is also
apparent from the 1H and the 13C NMR data that the two halves
of (L3)− in 2 are equivalent. For example, single resonances are
observed for the aromatic protons (C11H) and the imine protons
(C9H) and for the pairs of carbon atoms labelled C11, C11ꢀ and C12,
C
12ꢀ. Thus, complex 2 is C2v symmetric on the NMR time scale. This
Scheme 3 Synthesis of complexes 8–11.
is in contrast to the complexes 8 and 10 described below in which
the two palladium centres become inequivalent upon coordination
of bridging acetamidato units carrying two distinguishable N
and O donors. A similar NMR equivalence of the ligand side
arms has been noted for the dinuclear [(L5)Pd2(Cl)2]+ complex
All compounds gave satisfactory elemental analyses and were
1
characterized by spectroscopic methods (IR, H and 13C NMR
spectroscopy) and X-ray crystallography.
2116 | Dalton Trans., 2006, 2114–2126
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
Table 2 Selected 1H and 13C NMR data for the thioethers tBu–L3, tBu–L4 and the palladium complexes 2–9
C1H3
C4H3
C5H3
C6H3
C7H2
C8H2
C11H
C9H(C9H2)
tBu–L3,a
tBu–L4,a
2[ClO4]b
1.26
1.26
1.37
1.31
1.06
1.30
2.21
2.14
2.76
2.78
2.21
2.14
2.76
2.85
3.68
2.34
4.12
2.64
3.73
4.30
2.55
2.57
2.76
3.00
4.17
3.00
8.07
7.35
8.07
7.46
9.08
2.62
8.68
3.43
4.98
8.38
c
3[ClO4]2
c
4[ClO4]3
1.40
2.87
3.00
2.87
3.00
8.17
8.23
Coligand: 1.97 (CH3CN)
d
4[ClO4]3
1.42
4.44
3.17
8.47
Coligand: 2.24 (CH3CN)
6[ClO4]b
6[BPh4]b
1.43
1.35
1.40
2.77
2.70
2.81
2.77
2.70
2.83
4.17
4.08
4.07
4.15
2.83
2.75
2.73
2.87
8.22
8.14
8.12
8.13
8.79
8.71
8.36
8.59
c
8[ClO4]2
Coligand: 2.32 (CH3CONH), 6.15 (CH3CONH)
c
8[BPh4]2
1.40
2.75
2.75
3.93
4.00
2.63
2.71
8.08
8.15
8.40
Coligand: 2.30 (CH3CONH), 6.05 (CH3CONH)
b
9[ClO4]2
1.40
2.78
2.84
2.78
2.84
4.25
2.83
2.78
8.32
8.78
Coligand: 2.36 (CH3CO2)
b
10[ClO4]2
1.37
4.16
4.25
8.28
8.30
8.72
8.92
Coligand: 4.53 (ClCH2CONH), 7.47 (ClCH2CONH)
11[BPh4]e
1.39
2.86
2.86
4.02
4.08
C5
49.7
44.0
48.7
49.3
50.6
2.86
8.19
8.30
8.55
C8
60.5
57.5
64.8
56.9
67.3
C1
C2
C3
31.6
30.2
C4
46.2
47.6
C6
C7
C9
C10
C11
C12
C13
tBu–L3,a
tBu–L4,a
2[ClO4]e
31.5
29.8
30.6
30.2
31.0
35.5
33.3
35.7
34.5
36.1
49.7
44.0
51.8
51.7
53.2
60.2
51.9
62.9
54.2
62.8
163.3
44.8
165.2
63.2
168.4
152.9
150.8
151.8
151.6
153.8
141.6
144.3
139.6
136.0
142.7
131.6
124.4
134.2
128.7
133.4
127.2
126.7
128.7
129.9
127.4
c
3[ClO4]2
d
4[ClO4]3
Coligand: 4.4 (CH3CN), 123.3 (CH3CN)
6[ClO4]b
8[ClO4]2
30.8
31.0
34.9
35.9
49.3
49.6
49.3
50.7
61.3
64.6
63.6
66.7
165.9
166.8
167.7
150.2
153.1
139.5
142.3
142.9
133.6
133.6
135.1
121.9
125.5
d
Coligand: 24.1 (CH3CONH), 179.6 (CH3CONH)
c
8[BPh4]2
30.8
34.5
49.1
50.2
60.3
62.6
63.6
65.8
166.4
165.4
152.0
141.0
141.6
134.5
132.8
124.7
Coligand: 25.4 (CH3CONH), 180.7 (CH3CONH)
b
9[ClO4]2
30.1
34.4
48.1
48.6
48.1
49.7
59.6
64.9
166.0
150.5
150.9
140.5
132.5
122.4
122.9
Coligand: 24.1 (CH3CO2), 179.6 (CH3CO2)
b
10[ClO4]2
30.7
34.9
60.0
62.1
63.1
65.3
164.8
166.9
140.9
141.5
132.3
133.8
Coligand: 43.8 (ClCH2CONH), 174.8 (ClCH2CONH)
a Recorded in CDCl3 solution. b Recorded in DMSO-d6 solution. c Recorded in CD3CN solution. d Recorded in CD3NO2 solution. e Recorded in acetone-d6
solution.
1
where (L5)3− is the trianion derived from the condensation product
of cyclohexanecarbohydrazide and 2-mercapto-5-methylbenzene-
1,3-dialdehyde (Scheme 4).23
of the acetonitrile molecules. The H NMR spectrum of 5[ClO4]
showed only complicated multiplets in the aliphatic as well as in
the aromatic region and could not be analyzed. The same was
The 1H and 13C NMR spectral data for complex 3 were
also indicative of complete removal of the S-bonded tBu group,
showing only one singlet at d 1.31 for the C(10) bound para tBu
true for the 13C NMR spectrum. The H NMR of 6[ClO4] in
1
DMSO-d6 solution displays only one set of signals, indicating that
6 exists as a single isomer in solution. The tert-butyl, N-methyl,
aromatic and the imine protons all appear as singlets indicative of
local C2 or Cs-symmetry. This is also supported by the 13C NMR
1
group. The H NMR spectrum of 4[ClO4]3 in CD3NO2 solution
revealed a signal at d 2.24 ppm attributable to the methyl protons
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 2114–2126 | 2117
©

View Article Online
Scheme 4 Structures of ligands H3L5 and HL6.24,25
spectrum which displays only 10 signals (one for the imine, four
for the aromatic and five for the aliphatic carbon atoms). It can be
readily seen that the spectroscopic data for the acetate-complex 9
and the acetamido species 8 differ significantly from each other.
1
For example, the H NMR spectrum of 8 in CD3CN solution
reveals a signal at d 6.15 ppm that is not observed for the acetato
complex 9. This signal is readily assigned to the acetamidato NH
protons, as it vanishes in the presence of D2O due to NH/ND
exchange. Finally, the 13C NMR spectrum of 8[ClO4]2 shows six
signals for the aromatic protons whereas only four such signals are
observed for 9[ClO4]2. These data provide sufficient evidence for
the formulation of 8[ClO4]2 as a dipalladium complex coligated
by a deprotonated acetamide. The 1H and 13C NMR data for the
perchlorate salt 10[ClO4]2 are very similar to those of 8 and prove
the formulation of the acetamidato compounds.
Description of crystal structures
The X-ray crystal structures of complexes 2[ClO4], 3[ClO4]2·
MeOH, 4[ClO4]3, 5[BPh4]·MeCN, 6[BPh4]·MeCN, 7[ClO4]4·
2EtCN·MeCN, 9[ClO4]2, 10[ClO4]2 and 11[BPh4] were determined
to establish the geometries about the metal ions as well as the
bonding modes of the coligands. Experimental crystallographic
data are summarized in Table 3.
The crystal structure of 2[ClO4] consists of well-separated
[(L3)Pd2Cl2]+ complexes and perchlorate anions. Fig. 1 presents a
perspective view of the structure of 2 along with the atom labelling
scheme used. Selected bond lengths and angles are given in the
Figure caption.
The crystal structure determination of 2[ClO4] confirmed the
presence of the dichloro complex 2 of the novel imine-amine-
thiophenolate ligand (L3)−. Each palladium atoms is coordinated
by one bridging thiolate sulfur atom, two nitrogen atoms and
a terminal chloro ligand in a distorted square planar fash-
ion. The maximum deviations from the least-squares planes
defined by the atoms Pd(1), N(1), N(2), S, Cl(1) and Pd(2),
˚
N(3), N(4), S, Cl(2) are 0.043 and 0.048 A, respectively. The
overall conformation of (L3)− in 2 is very similar to that
of the related diimine-dipyridyl-thiophenolate ligand (L6)− in
[(L6)Pd2Cl2]+ (HL6 = 2,6-bis((2-(pyridin-2-yl)ethylimino)methyl)-
4-methylbenzenethiol, Scheme 4).24 For example, in both com-
pounds the two coordination planes are markedly twisted around
the hinging sulfur atoms presumably as a consequence of repulsive
interactions between the two chloro ligands. Likewise, in both
structures the side arm associated with Pd(2) is much more twisted
out of the plane of the central aromatic unit than the other. In 2,
the coordination plane of Pd(1) is at a dihedral angle of 18.6◦ to
the central aromatic ring whereas the corresponding angle for the
2118 | Dalton Trans., 2006, 2114–2126
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
Again, each palladium atom is coordinated by one bridging
thiolate sulfur atom, two nitrogen atoms and a chloro ligand, but
in contrast to 2 the latter is in a bridging mode. As a consequence,
˚
the distance between the Pd atoms is much shorter at 3.087 A
and the Pd–S–Pd angle has decreased to 85.84◦. The side arms
associated with Pd(1) and Pd(2) are now equally twisted out of the
plane of the central aromatic unit. Thus, the coordination planes
of Pd(1) and Pd(2) are at similar dihedral angles of 34.1 and 43.1◦
to the central aromatic ring. This in turn results in an idealized Cs
symmetry for the dication 3. The average Pd–N, Pd–S and Pd–Cl
bond lengths are unexceptional and compare well with those of
other four-coordinate N2S2Pd or PdN2SCl complexes.25,26
It should be noted that metal-ion promoted C–S bond cleavage
reactions have been reported previously for a large number
of aliphatic thioether ligands.27 The related ring opening of
cyclic thioethers via C–S bond cleavage is also well-documented.
For example, macrocyclic 1,4,7-trithiacyclononane is known to
reversibly react with RhIII ions to afford vinyl thioether–thiolate
complexes in basic solution.28 However, there have been only
few reports in the literature concerning sulfur desalkylations of
aromatic thioether compounds such as tBu–L3 or tBu–L4. This
metal-ion promoted cleavage of thioether ligands is of interest in
several respects. It not only represents a convenient method for the
deprotection of thiolate sulfur atoms.29–31 It is also of importance in
the design and synthesis of new ligands for more robust thioether
complexes.32
Fig. 1 Structure of the cation 2 in crystals of [(L3)Pd2Cl2][ClO4] (2[ClO4])
with thermal ellipsoids drawn at the 50% probability level. Hydrogen
˚
atoms are omitted for reasons of clarity. Selected bond lengths (A) and
angles (◦): Pd(1)–N(1) 1.978(5), Pd(1)–N(2) 2.091(5), Pd(1)–S 2.252(2),
Pd(1)–Cl(1) 2.296(2), Pd(2)–N(3) 2.000(5), Pd(2)–N(4) 2.105(5), Pd(2)–S
2.280(2), Pd(2)–Cl(2) 2.299(2); Pd(1) · · · Pd(2) 3.922(1), Cl(1) · · · Cl(2)
3.633(2); Pd(1)–S–Pd(2) 119.87(7).
coordination plane of Pd(2) is at 48.3◦. For [(L6)Pd2Cl2]+, these
angles are very similar at 13.9 and 62.5◦, respectively. It is also
worth mentioning that both compounds reveal significant strain
around the thiophenolate sulfur atoms. This strain is manifested
in the displacement of the sulfur atom from the average plane of
Although, the structure determination of 4[ClO4]3 is of low
quality and not as good as desired for publication,33 it can serve
to confirm the formulation and the atom connectivity of the
bisacetonitrile complex 4. The structure is depicted in Fig. 3, but
not discussed further.
6
+
˚
the benzene ring to which it is attached (0.223 A in [(L )Pd2Cl2] ,
˚
0.304 A in 2).
Single crystals of 3[ClO4]2·MeOH were grown by recrystalliza-
tion from methanol. A perspective view of the structure of 3
together with the atomic numbering scheme is shown in Fig. 2.
Fig. 3 Structure of the trication 4 in crystals of [(L3)Pd2(NCMe)2][ClO4]3
(4[ClO4]3) with thermal ellipsoids drawn at the 50% probability level.
Hydrogen atoms are omitted for reasons of clarity. Only one orientation of
the disordered tBu group and the disordered S atom is displayed. Symmetry
code used to generate equivalent atoms: (ꢀ) −x, +y, 1.5 − z.
Fig. 2 Structure of the cation 3 in crystals of [(L4)Pd2(l-Cl)][ClO4]2
(3[ClO4]2) with thermal ellipsoids drawn at the 50% probability level.
Hydrogen atoms are omitted for reasons of clarity. Selected bond
◦
The crystal structure determination of 5[BPh4]MeCN revealed
˚
lengths (A) and angles ( ): Pd(1)–N(1) 2.016(9), Pd(1)–N(2) 2.120(8),
the presence of well-separated complexes of the diisothiocyanate
Pd(1)–S 2.257(2), Pd(1)–Cl(1) 2.359(3), Pd(2)–N(3) 2.026(8), Pd(2)–N(4)
2.075(8), Pd(2)–S 2.275(2), Pd(2)–Cl(1) 2.376(3), Pd(1) · · · Pd(2) 3.087(1);
Pd(1)–S–Pd(2) 85.84(8), Pd(1)–Cl(1)–Pd(2) 81.36(8).
−
complex 5, BPh4 anions and acetonitrile molecules of solvation
(Fig. 4). The palladium atoms are four-coordinate and bind the
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 2114–2126 | 2119
©

View Article Online
Fig.
4
Structure of the isothiocyanato complex 5 in crystals of
[(L3)Pd2(SCN)2][BPh4]·MeCN (5[BPh4]·MeCN). Thermal ellipsoids are
Fig. 5 Structure of the azido complex 6 in crystals of [(L3)Pd2(N3)2]-
[BPh4]·MeCN (6[BPh4]·MeCN) with thermal ellipsoids drawn at the 50%
probability level. Hydrogen atoms are omitted for reasons of clarity.
drawn at the 50% probability level. Hydrogen atoms are omitted for
◦
˚
reasons of clarity. Selected bond lengths (A) and angles ( ): Pd(1)–N(1)
1.994(4), Pd(1)–N(2) 2.114(4), Pd(1)–S(1) 2.256(2), Pd(1)–S(2) 2.313(2),
Pd(2)–N(3) 2.019(4), Pd(2)–N(4) 2.112(4), Pd(2)–S(1) 2.274(1), Pd(2)–S(2)
2.316(2), S(2)–C(21) 1.693(8), S(3)–C(22) 1.668(6), N(5)–C(21) 1.159(8),
N(6)–C(22) 1.138(6), Pd(1) · · · Pd(2) 3.877(1); C(21)–S(2)–Pd(1) 102.8(2),
C(22)–S(3)–Pd(2) 101.16(19), N(5)–C(21)–S(2) 174.5(7), N(6)–C(22)–S(3)
177.6(5), Pd(1)–S(1)–Pd(2) 117.7.
◦
˚
Selected bond lengths (A) and angles ( ): Pd(1)–N(1) 1.959(5), Pd(1)–N(2)
2.088(5), Pd(1)–N(5) 2.003(6), Pd(1)–S 2.245(1), Pd(2)–N(3) 1.998(4),
Pd(2)–N(4) 2.099(4), Pd(2)–N(8) 2.009(5), Pd(2)–S 2.257(1), N(5)–N(6)
1.175(7), N(6)–N(7) 1.138(7), N(8)–N(9) 1.186(7), N(9)–N(10) 1.141(7),
Pd(1) · · · Pd(2) 3.971(1); Pd(1)–N(5)–N(6) 127.6(5), Pd(2)–N(8)–N(9)
122.2(4), N(5)–N(6)–N(7) 175.2(7), N(8)–N(9)–N(10) 174.4(7).
thiocyanates via their S atoms in a monodentate fashion. One of
the thiocyanates is coordinated in such a way that its CN function
is located above the Pd(1) plane, but the long Pd(1) · · · C(22)
an angle of 54.8◦ to each other. Likewise, the side arm associated
with Pd(2) is much more twisted out of the plane of the central
aromatic unit than the other. The coordination plane of Pd(1) is
at a dihedral angle of 17.7◦ to the central aromatic ring whereas
the corresponding angle for the coordination plane of Pd(2) is
at 37.7◦. Significant strain around the thiophenolate sulfur atom
is also manifested in 6 in the displacement of the S atom from
the average plane of the benzene ring to which it is attached by
˚
distance at 3.278 A is too long for a secondary Pd · · · NCS bonding
interaction. This is also supported by the CN and CS distances
which reveal no significant elongation or contraction from the
usual values.34 Interestingly, the Pd–S bond lengths involving the
˚
thiocyanate ions (mean 2.315 A) are longer than those involving
˚
the thiophenolate sulfur atom (2.265 A) despite the fact that the
˚
latter is a bridging atom. These values should be compared with
the corresponding Pd–Cl and Pd–l-Cl distances in 2, where the
reverse situation is observed. The conformation of (L3)− adopted
in 5 is very similar to that in 2. Thus, the two coordination planes
are again markedly twisted around the hinging sulfur atom so that
they are at an angle of 68.1◦ to each other (66.1◦ in 2). Likewise,
the side arm associated with Pd(2) is much more twisted out of the
plane of the central aromatic unit than the other. The coordination
plane of Pd(1) is at a dihedral angle of 18.8◦ to the central aromatic
ring whereas the corresponding angle for the coordination plane of
Pd(2) is at 50.5◦. These values are essentially identical with those in
2 (18.6, 48.3◦). Finally, significant strain around the thiophenolate
sulfur atom is also manifested in 5 in its displacement from the
0.210 A.
Single crystals of 7[ClO4]4·2EtCN·MeCN were grown from a
mixed propionitrile/acetonitrile solvent system. This salt crys-
tallizes in the space group C2/c. A perspective view of the
molecular structure of 7 is shown in Fig. 6. Complex 7 possesses
crystallographically imposed C2 symmetry. Two [(L3)Pd2]2+ units
are linked via two l1,2-bridging cyanide ions to give a tetranuclear
Pd(II) complex. The separation of the l1,2-CN-bridged Pd atoms is
˚
at 5.090 A, which is much longer than the Pd · · · Pd distances in the
[(L3)Pd2]2+ units at 3.981 A. It should be noted that the orientation
˚
of the cyanides could not be determined unambiguously from
the present data set. The R values for the two orientations
are within experimental error identical. It is also significant
that for the present orientation (see Fig. 6) the Ueq values for
the cyanide carbon (Ueq(C(21)) = 0.026(1)) and nitrogen atoms
(Ueq(N(5)) = 0.44(1) are either smaller or larger than the arithmetic
average of the Ueq values of a selected number of carbon atoms
(C(1)–C(6), average Ueq = 0.0368). The reverse is true for the
alternate orientation. This is indicative of a statistical distribution
(∼50/50%) of the two possible orientations. Thus, the bond
lengths given in the figure caption should be taken as indicative
rather than definitive.
˚
average plane of the benzene ring to which it is attached by 0.315 A
˚
(0.304 A 2).
Fig. 5 shows the structure of complex 6 in crystals of
6[BPh4]·MeCN. As can be seen, the two azide ions are both
coordinated in an end-on fashion. The average Pd–N(azide)
˚
bond length at 2.006 A and the average Pd–N–NN bond an-
gle at 124.9◦ are normal for four-coordinate palladium azido
complexes.35 In [Pd(py)2(N3)2], for example, the mean P–N(azide)
˚
bond◦lengths and Pd–N–NN bond angles are at 2.037 A and
125.2 , respectively.36 The conformation of (L3)− adopted in 6 is
very similar to that in 2 and 5. The two coordination planes are at
Crystals of 10[ClO4]2 grown by recrystallization from acetoni-
trile are triclinic, space group P1. Fig. 7 displays the structure of
¯
2120 | Dalton Trans., 2006, 2114–2126
This journal is The Royal Society of Chemistry 2006
©

View Article Online
present orientation of the 2-chloroacetamide with the N atom
bonded to Pd(1) and the O atom bonded to Pd(2), respectively,
has been assigned correctly. This also follows from the R1 values
which converged at R1 = 0.0421 for the present structure and at a
slightly higher value (R1 = 0.0432) for the alternate orientation.
Fig. 8 shows the structure of the dication 9 along with the atomic
labelling scheme. Each palladium features a planar coordination
comprised of tertiary amine, imine and thiophenolate sulfur atoms
from the supporting ligand and one oxygen atom of a l1,3-bridging
acetate ion. The metal–ligand bond lengths in the acetato-bridged
complex 9 are practically identical with those in the acetamidato-
bridged compound 10. The same is true for the Pd · · · Pd distance
Fig.
6
Structure of the cyanide complex
7
in crystals of
˚
at 3.685 A. The major difference occurs in the C(22)–C(21)–
[{(L3)Pd2(l-CN)2}2][ClO4]4·(EtCN)2·MeCN (7[ClO4]4·(EtCN)2·MeCN)
with thermal ellipsoids drawn at the 50% probability level. tert-Butyl
groups, NMe groups and hydrogen atoms are omitted for reasons
O(2)–Pd(2) and O(1)–C(21)–O(2)–Pd(2) torsional angles which
are somewhat larger (by ∼10◦) in 10.
of clarity. Selected bond lengths (A) and angles (◦): Pd(1)–N(1)
˚
1.983(5), Pd(1)–N(2) 2.096(5), Pd(1)–C(21) 1.974(5), Pd(1)–S 2.2685(16),
Pd(2)–N(3) 1.998(5), Pd(2)–N(4) 2.094(6), Pd(2)–N(5) 1.989(6),
Pd(2)–S 2.2904(18), Pd(1) · · · Pd(2) 3.981(1), C(21)–N(5)ꢀ 1.136(7);
Pd(1)–C(21)–N(5)ꢀ 177.8(6), C(21)ꢀ–N(5)–Pd(2) 173.9(5). Symmetry code
used to generate equivalent atoms: 2 − x, +y, 0.5 − z.
Fig. 8 Structure of the cation 9 in crystals of [(L3)Pd2(OAc)][ClO4]2
(9[ClO4]2) with thermal ellipsoids drawn at the 50% probability level.
Hydrogen atoms are omitted for reasons of clarity. Selected bond
◦
˚
lengths (A) and angles ( ): Pd(1)–N(1) 1.979(5), Pd(1)–N(2) 2.097(5),
Pd(1)–S 2.242(2), Pd(1)–O(1) 2.031(5), Pd(2)–N(3) 1.993(5), Pd(2)–N(4)
2.093(5), Pd(2)–S 2.254(2), Pd(2)–O(2) 2.022(5), Pd(1) · · · Pd(2) 3.685,
O(1) · · · O(2) 2.287(5), O(1)–C(21) 1.292(8), O(2)–C(21) 1.283(8);
Pd(1)–O(1)–C(21) 127.6(5), Pd(2)–O(2)–C(21) 127.5(5), O(1)–C(21)–O(2)
125.3(6), C(22)–C(21)–O(1)–Pd(1) 15.1, O(2)–C(21)–O(1)–Pd(1) 13.2,
C(22)–C(21)–O(2)–Pd(2) 48.1, O(1)–C(21)–O(2)–Pd(2) 49.9.
Fig. 7 Structure of the 2-chloroacetamido complex 10 in crystals of
[(L3)Pd2(NHOCCH2Cl)2][ClO4]2 (10[ClO4]2) with thermal ellipsoids drawn
at the 50% probability level. Hydrogen atoms are omitted for reasons of
◦
˚
clarity. Selected bond lengths (A) and angles ( ): Pd(1)–N(1) 1.994(4),
Pd(1)–N(2) 2.103(4), Pd(1)–S 2.252(1), Pd(1)–N(5) 2.021(4), Pd(2)–N(3)
1.981(4), Pd(2)–N(4) 2.099(4), Pd(2)–S 2.2700(1), Pd(2)–O(1) 2.023(4),
Pd(1) · · · Pd(2) 3.688, O(1) · · · N(5) 2.294, N(5)–C(21) 1.285(7), O(1)–
C(21) 1.290(6); Pd(2)–O(1)–C(21) 129.1(4), Pd(1)–N(5)–C(21) 129.9(4),
O(1)–C(21)–N(5) 125.9(5), C(22)–C(21)–N(5)–Pd(1) 18.9, O(2)–C(21)–
N(5)–Pd(1) 14.5, C(22)–C(21)–O(1)–Pd(2) 38.2, C(22)–C(21)–O(1)–Pd(2)
42.6.
The metal-mediated hydration of nitriles has been observed
previously for a number of mono- and binuclear complexes.37,38
In the binuclear palladium thiophenolate complexes [(L5)Pd2(l-
Lꢀ)2]+ and [(L6)Pd2(l-Lꢀ)2]+, the nitrile hydration proceeds by a
two-metal ion mechanism in which a nucleophilic hydroxide ion
bound to one palladium atom attacks the activated nitrile bound to
the adjacent palladium, as outlined in Scheme 5. It is assumed that
hydration of nitriles by the [(L3)Pd2]3+ units proceeds in a similar
10. Selected bond lengths and angles are given in the figure caption.
The 2-chloroacetamidato unit bridges the two palladium atoms in
a l1,3-bridging mode to generate a N3S coordination environment
for Pd(1) and a N2OS coordination environment for Pd(2). The
˚
Pd · · · Pd distance is at 3.688 A. The Pd–O and Pd–N bond lengths
are identical, indicative of sp2-hybridized N and O atoms and a
delocalized electronic structure of the carboxamidato function.
This is supported by the fact that the amide NH hydrogen atom is
coplanar with the amidato plane. It should be noted in this respect
that the NH hydrogen atom H(1) could be located unambiguously
from difference Fourier maps providing strong support that the
Scheme 5 Hydration of nitriles in binuclear palladium complexes.
Dalton Trans., 2006, 2114–2126 | 2121
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
manner. The reactive hydroxo intermediate A may be generated by
substitution of an acetonitrile by a water molecule and subsequent
deprotonation of the aqua complex. The nucleophilic attack of the
hydroxide on the adjacent nitrile and a final proton shift then yields
the amidato-bridges in 8 and 10.
Experimental
All syntheses were carried out under a protective atmosphere of
argon. Melting points were determined in open glass capillaries
and are uncorrected. NMR spectra were recorded on a Bruker
AVANCE DPX-200 spectrometer at 300 K. Chemical shifts
refer to solvent signals. Infrared spectra were recorded on a
Bruker VECTOR 22 FT-IR-spectrometer. Elemental analyses
were carried out with a VARIO EL-elemental analyzer.
1
Fig. 9 shows the structure of 11. Both phenyl groups are g -
coordinated to the planar palladium atoms. The average Pd–C
˚
distance of 1.991 A is normal for four-coordinate palladium(II)
1
complexes with g -phenyl ligation.39 The planes through the phenyl
rings are neither coplanar nor perpendicular to the PdN2SC
planes indicative of negligible Pd(dp)–aryl(pp*) back bonding
interactions. However, the Pd–N(imine) bond lengths in 11 are
slightly longer than in 2–10 indicative of a small trans effect of the
phenyl group.
Caution! Perchlorate salts are potentially explosive and should
therefore be prepared only in small quantities and handled with
appropriate care.
Preparation of tBu–L3
To a solution of Nꢀ,Nꢀ-dimethylethane-1,2-diamine (85 mg,
0.96 mmol) in ethanol (20 mL) was added a solution of
5-tert-butyl-2-(tert-butylthio)benzene-1,3-dialdehyde15 (134 mg,
0.48 mmol) in dichloromethane (10 mL). The reaction mixture
was stirred for 24 h. Evaporation to dryness gave a colourless
oil which crystallized on standing. Yield: 201 mg (0.48 mmol,
◦
100%). Mp 58 C. IR (KBr pellet, cm−1): m˜ = 3419(s), 3255(w),
3056(s), 2963(m), 2894(m), 2851(m), 2813(s), 2764(s), 1692(m),
=
1632(s) m(C N), 1587(w), 1456(s), 1404(w), 1391(w), 1362(s),
1342(m), 1287(m), 1272(m), 1240(m), 1226(m), 1182(w), 1165(w),
1151(w), 1137(m), 1098(w), 1066(w), 1044(m), 1033(m), 973(w),
953(w), 934(m), 899(w), 881(w), 784(m), 748(w), 669(w), 644(w).
Elemental analysis: calc. (%) for C24H42N4S (418.68): C 68.85, H
10.11, N 13.38, S 7.66; found: C 68.67, H 10.10, N 12.66, S 7.79.
Preparation of tBu–L4
1
Fig. 9 Structure of the cation 11 in crystals of [(L3)Pd2(g -Ph)2][BPh4]
To a solution of Nꢀ,Nꢀ-dimethylethane-1,2-diamine (566 mg,
6.42 mmol) in ethanol (50 mL) was added
(11[BPh4]) with thermal ellipsoids drawn at the 50% probability level.
a solution
Hydrogen atoms ◦are omitted for reasons of clarity. Selected bond lengths
˚
of 5-tert-butyl-2-(tert-butylthio)benzene-1,3-dialdehyde (892 mg,
3.20 mmol) in dichloromethane (10 mL). After stirring for 12 h,
sodium borohydride (244 mg, 6.44 mmol) was added and the
mixture was stirred for further 4 h. The solution was acidified
with 12 M HCl and evaporated to dryness. Water (50 mL) was
added and the pH of the solution adjusted to 10 by addition of
3 M potassium hydroxide solution. The product was extracted
with dichloromethane (3 × 50 mL). The organic fractions were
combined, dried with K2CO3 and evaporated to dryness to give
a colourless oil. Yield: 1.20 g (88%). This compound was used
without further purification for the preparation of the metal
complexes.
(A) and angles ( ): Pd(1)–N(1) 2.049(4), Pd(1)–N(2) 2.128(4), Pd(1)–S
2.241(1), Pd(1)–C(21) 1.998(5), Pd(2)–N(3) 2.066(4), Pd(2)–N(4) 2.133(4),
Pd(2)–S 2.265(1), Pd(2)–C(27) 1.983(5), Pd(1) · · · Pd(2) 3.925.
Conclusion
The aromatic thioethers tBu–L3 and tBu–L4 can be readily de-
protected with PdCl2(NCMe)2 to afford the binucleating diimine-
diamine- and tetraamine-thiophenolate ligands (L3)− and (L4)−,
respectively. These ligands support the formation of dinuclear
complexes of the type [(L3)Pd(Lꢀ)2]n+ and [(L4)Pd2(l-Lꢀ)]n+, demon-
strating that the conversion of the two imine-functions in the
lateral side arms of (L3)− to amine functions in (L4)− can be
used to adjust the type and number of their active coordination
sites. The dichloro-complex [(L3)Pd2(Cl)2]+ exhibits a rich coor-
dination chemistry as illustrated by the synthesis and structural
characterization of the corresponding acetonitrile, azido, cyanide,
isothiocyanato and phenyl complexes. It has also been established
that the [(L3)Pd2]3+ fragment mediates the hydration of nitrile
ligands. Work in progress is now directed towards the catalytic
activity of these compounds by taking advantage of the reactive
dipalladium site offered by the supporting ligand. Such com-
pounds may also aid in an understanding of cooperative effects in
binuclear catalysis.
Preparation of [(L3)Pd2Cl2][ClO4] (2[ClO4])
To a solution of Nꢀ,Nꢀ-dimethylethane-1,2-diamine (1.00 g,
11.3 mmol) in ethanol (50 mL) was added
a solution
of 5-tert-butyl-2-(tert-butylthio)benzene-1,3-dialdehyde (1.58 g,
5.67 mmol) in dichloromethane (50 mL). The solution was stirred
for 24 h after which it was evaporated to dryness. The residue was
redissolved in acetonitrile (100 mL) and combined with a solution
of PdCl2(NCMe)2 (2.94 g, 11.3 mmol) in acetonitrile (150 mL).
The reaction mixture was stirred for 2 days, evaporated to dryness,
and the residue was dissolved in dimethylformamide (5 mL).
To this solution was added a solution of LiClO4·3H2O (3.00 g,
2122 | Dalton Trans., 2006, 2114–2126
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
18.7 mmol) in methanol (200 mL). The resulting yellow solid
was filtered off, air-dried and recrystallized from an acetonitrile–
ethanol mixed solvent system. Yield: 2.93 g (3.93 mmol, 69%).
910(m), 815(m), 780(s), 684(m), 623(s). Elemental analysis calc.
(%) for C22H33ClN6O4Pd2S3 (790.02): C 33.45, H 4.21, N 10.64, S
12.18; found: C 33.04, H 4.63, N 10.35, S 11.07. To a solution of
the perchlorate salt 5[ClO4] (100 mg, 0.127 mmol) in acetonitrile
(10 mL) was added a solution of NaBPh4 (500 mg, 1.46 mmol) in
methanol (10 mL). The solution was concentrated in vacuum (final
volume ∼5 mL). A few crystals of 5BPh4 separated on standing
◦
Mp 294 C (decomp.). IR (KBr pellet, cm−1): m˜ = 3423(s),
=
3060(m), 2962(s), 2931(m), 2871(m), 2840(w), 1637(s) m(C N),
=
1569(w), 1544(m), 1459(s) m(C C), 1396(w), 1365(w), 1232(m),
1145(m), 1088(s) m(ClO4), 1007(w), 945(w), 943(w), 909(w),
780(m), 731(w), 689(s), 624(m), 503(w). Elemental analysis: calc.
(%) for C20H33Cl3N4O4Pd2S·MeCN (744.76 + 41.05): C 33.63, H
4.62, N 8.91, S 4.08; found: C 33.14, H 4.53, N 8.57, S 3.45.
◦
overnight. Mp 220 C (decomp.). IR (KBr pellet, cm−1): m˜ =
3432(br s), 3051(w), 3030(w), 2964(s), 2927(m), 2108 (vs) m(NCS),
=
=
1636(s) m(C N), 1579(m), 1508(m), 1465(s) m(C C), 1427(m),
1365(w), 1229(m), 1182(w), 1146(w), 1082(m), 1007(w), 953(w),
908(w), 845(m), 778(m), 747(s), 738(s) m(BPh4), 708(s) m(BPh4),
610(s). Elemental analysis: calc. (%) for C46H57BN6O2Pd2S3·2H2O
(1045.83 + 36.03): C 52.83, H 5.49, N 8.04, S 9.20; found: C
52.38, H 5.08, N 8.30, S 9.03. This compound was additionally
characterized by X-ray diffraction.
Preparation of [(L4)Pd2(l-Cl)][ClO4]2 (3[ClO4]2)
To a solution of tBu–L4 (106 mg, 0.250 mmol) in dichloromethane
(10 mL) was added a solution of PdCl2(MeCN)2 (129 mg,
0.500 mmol) in acetonitrile (40 mL). The reaction mixture was
allowed to stir for further 12 h at ambient temperature and was
then evaporated to dryness. The residue was taken up in methanol
(50 mL) and filtered. To the clear filtrate was added a solution of
LiClO4·3H2O (1.00 g, 6.24 mmol) in methanol (10 mL) to give the
title compound as a yellow solid. The crude product was purified
by recrystallization from acetonitrile. Yield: 156 mg (77%). Mp
244 ◦C. IR (KBr pellet, cm−1): m˜ = 3430(s), 3202(w) m(NH), 2958(s),
2902(s), 1778(m), 1658(w), 1629(m), 1548(m), 1528(w), 1478(m),
Preparation of [(L3)Pd2(N3)2][BPh4] (6[BPh4])
To a solution of 3[ClO4]3 (300 mg, 0.315 mmol) in acetone (180 mL)
was added a solution of NaN3 (41 mg, 0.63 mmol) in 1% aqueous
methanol (50 mL). The mixture was allowed to stir for 24 h. Upon
concentration of the solution (final volume ∼10 ml) a red–yellow
solid (6[ClO4]) formed. This material was filtered off, washed with
a few millilitres of methanol and dried in air. Yield: 193 mg
(0.255 mmol, 81%). Mp 250 ◦C (decomp.). IR (KBr pellet, cm−1):
m˜ = 3430(br s), 3066(w), 2961(s), 2938(s), 2035 (vs) mas(N3), 1640(s)
=
1464(s) m(C C), 1442(m), 1394(w), 1365(w), 1337(w), 1309(w),
1229(m), 1146(m), 1122(vs), 1109(vs) m(ClO4), 1093(vs), 999(m),
944(w), 907(w), 888(w), 784(m), 745(w), 697(w), 623(s). Elemental
analysis: calc. (%) for C20H37Cl3N4O8Pd2S·H2O (812.79 + 41.05):
C 28.91, H 4.73, N 6.74, S 3.86; found: C 28.84, H 4.79, N 5.58, S
3.35.
=
=
m(C N), 1544(m), 1464(s) m(C C), 1437(m), 1397(w), 1365(w),
1292(m) ms(N3), 1237(m) ms(N3), 1086(vs) m(ClO4), 1008(w), 966(w),
956(w), 942(w), 908(w), 817(m), 729(w), 623(s). Elemental analy-
sis: calc. (%) for C20H33ClN10O4Pd2S (757.90): C 31.69, H 4.39,
N 18.48, S 4.23; found: C 31.80, H 4.62, N 17.83, S 4.00.
To a solution of 6[ClO4] (100 mg, 0.132 mmol) in acetonitrile
(10 mL) was added a solution of NaBPh4 (500 mg, 1.46 mmol)
in methanol (10 mL). The solution was concentrated in vacuum
(final volume ∼10 mL). Orange-coloured crystals separated on
standing overnight. Mp 180 ◦C (decomp.). IR (KBr pellet, cm−1):
m˜ = 3430(br s), 3051(m), 3035(m), 2964(s), 2926(s), 2029(vs)
Preparation of [(L3)Pd2(NCMe)2][ClO4]3 (4[ClO4]3)
The dichloro complex 2[ClO4] (1.00 g, 1.34 mmol) and anhydrous
lead perchlorate (1.00 g, 2.46 mmol) were dissolved in acetonitrile
(230 mL). The resulting mixture was stirred for 4 h and filtered off
from PbCl2. The title compound crystallized upon evaporation
of ca. 90% of the solvent. The yellow microcrystalline material
was filtered off and dried in air. Yield: 972 mg (1.02 mmol, 76%).
IR (KBr pellet, cm−1): m˜ = 3424(br), 3282(w), 3058(w), 2964(s),
2934(s), 2873(w), 2812(w), 2724(w), 2330(m) m(C≡N), 2303(m)
=
mas(N3), 2012(vs) mas(N3), 1636(s) m(C N), 1578(m), 1542(w),
1457(s) m(C C), 1427(m), 1395(w), 1288(m) ms(N3), 1228(m)
ms(N3), 1178(w), 1032(w), 955(w), 908(w), 941(w), 907(w), 733(s)
m(BPh4), 707(s) m(BPh4), 612(s). Elemental analysis: calc. (%) for
C44H53BN10Pd2S (977.68): C 54.05, H 5.46, N 14.33, S 3.28; found:
C 53.47, H 5.58, N 14.76, S 3.04.
=
=
m(C≡N), 2017(w), 1645(s) m(C N), 1595(w), 1545(m), 1467(s)
=
m(C C), 1398(w), 1368(w), 1331(w), 1234(m), 1141(vs), 1100(vs)
(ClO4), 1006(w), 954(w), 941(w), 910(w), 780(m), 729(m), 625(s).
Elemental analysis: calc. (%) for C24H39Cl3N6O12Pd2S (954.86): C
30.19, H 4.12, N 8.80, S 3.36; found: C 29.78, H 4.27, N 8.60, S
2.85.
Preparation of [{(L3)Pd2(CN)2}2][ClO4]4 (7[ClO4]4)
A solution of 2·ClO4 (100 mg, 134 mmol) and Pb(ClO4)2 (100 mg,
246 mmol) in propionitrile (80 mL) was stirred for 12 h. The
solution was filtered off from PbCl2 and concentrated in vacuum
to 10 mL. The resulting yellow solid was filtered off, washed
with a few millilitres of◦propionitrile and dried in air. Yield:
60 mg (56%). Mp 260 C (decomp.). IR (KBr pellet, cm−1):
m˜ = 3419(br s), 2965(s), 2872(m), 2183(m) m(C≡N), 1638(s)
Preparation of [(L3)Pd2(SCN)2][BPh4] (5[BPh4])
To a solution of 4[ClO4]3 (100 mg, 0.105 mmol) in acetone
(60 mL) was added a solution of NaSCN (17 mg, 0.21 mmol)
in methanol (1 mL). The mixture was allowed to stir for 24 h.
Upon concentration of the solution (final volume ∼10 ml) a
red–yellow solid formed. This material was filtered off, washed
with a few millilitres of methanol and dried in air. Yield: 44 mg
(0.056 mmol, 53%). Mp 282 ◦C (decomp.). IR (KBr pellet, cm−1):
m˜ = 3443(br s), 2959(s), 2935(s), 2868(m), 2108 (vs) m(NCS), 1637(s)
=
=
m(C N), 1545(s), 1460(w) m(C C), 1405(w), 1378(w), 1233(m),
1144(s), 1088(vs) m(ClO4), 1008(m), 960(m), 953(m), 941(m),
908(m), 780(s), 729(w), 636(s), 626(s). Elemental analysis: calc.
(%) for C21H33Cl2N5O8Pd2S (799.33): C 31.55, H 4.16, N 8.76, S
4.01; found: C 31.46, H 4.34, N 8.58, S 3.19. This compound
=
=
m(C N), 1541(m), 1461(s) m(C C), 1408(w), 1394(w), 1366(w),
1340(w), 1229(s), 1165(w), 1087(vs) m(ClO4), 1006(s), 941(s),
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 2114–2126 | 2123
©

View Article Online
=
was additionally characterized by an X-ray crystal structure
determination
1462(s) m(C C), 1437(s) ms(OAc), 1238(m), 1189(m), 1174(w),
1160(w), 1120(s), 1082(vs) m(ClO4), 1027(m), 999(w), 954(w),
907(w), 779(s), 726(w), 680(w), 623(s). Elemental analysis: calc.
(%) for C22H37Cl2N4O10Pd2S (833.36): C 31.71, H 4.48, N 6.72, S
3.85; found: C 31.54, H 4.38, N 6.63, S 3.67.
Preparation of [(L3)Pd2(l1,3-MeCONH)][ClO4]2 (8[ClO4]2)
Method A: To a solution of 4[ClO4]3 (100 mg, 0.105 mmol) in
acetone (10 mL) was added 5% aqueous methanol (20 mL).
The mixture was stirred at room temperature for 12 h. The
resulting yellow solid was filtered off, washed with methanol
and dried in air. Yield: 53 mg (61%). Mp 220 ◦C (decomp.).
Method B: Compound 3[ClO4]3 (100 mg, 0.105 mmol) was
dissolved in hot water (60 ◦C). The title compound crystallized
on cooling. This material was filtered and dried over phospho-
rous pentaoxide. Yield: 60 mg (69%). Method C: A suspension
of compound 3[ClO4]3 (100 mg, 0.105 mmol) in water was
stirred for four days at room temperature. The solid was then
filtered off and dried over P4O10. Yield: 65 mg (74%). IR (KBr
pellet, cm−1): m˜ = 3316(s) m(N–H), 3069(w), 2966(m), 2871(m),
Preparation of [(L3)Pd2(l-ClCH2CONH)][ClO4]2 (10[ClO4]2)
The dichloro complex 2[ClO4] (74 mg, 0.10 mmol) and anhydrous
lead perchlorate(100 mg, 0.246mmol)weredissolved in chloroace-
tonitrile (10 mL). The resulting mixture was stirred for 4 h and
filtered off from PbCl2. To this solution was added 5% aqueous
methanol (20 mL). The solution was concentrated in vacuum. The
resulting yellow solid was filtered off, washed with ethanol, and
dried in vacuum. Yield: 85 mg (91%). IR (KBr pellet, cm−1): m˜ =
3429(br s), 3309(s) m(N–H), 3066(w), 3031(w), 2966(s), 2871(w),
=
=
1649(s) m(C N), 1630(s) m(C N), 1573 mas(CONH), 1545(m),
=
1459(s) m(C C), 1414(w) m(CONH), 1396(w), 1368(w), 1348(w),
=
=
2837(vw), 1648(s) m(C N), 1628(s) m(C N), 1553(s) mas(CONH),
1336(w), 1303(w), 1095(vs) m(ClO4), 1001(w), 972(w), 953(w),
910(w), 814(w), 780(s), 730(w), 624(s). Elemental analysis: calc.
(%) for C22H36Cl3N5O9Pd2S (865.81): C 30.52, H 4.19, N 8.09, S
3.70; found: C 30.57, H 4.21, N 8.08, S 3.48.
=
1477(s) m(C C), 1458(w), 1436(w) msym(CONH), 1399(w), 1368(w),
1344(w), 1336(w), 1308(vw), 1241(s), 1234(s), 1236(s), 1099(vs)
m(ClO4), 1002(w), 971(w), 955(w), 941(w), 903(m), 778(m), 730(w),
624(s). Elemental analysis: calc. (%) for C22H37Cl2N5O9Pd2S
(831.37): C 31.78, H 4.49, N 8.42, S 3.86; found: C 31.52, H 4.56,
N 8.18, S 3.79.
Preparation of [(L3)Pd2(Ph2)][BPh4] (11[BPh4])
To a solution of 3[ClO4]3 in acetonitrile (10 mL) was added a
solution of NaBPh4 (370 mg, 1.08 mmol) in acetonitrile. Ethanol
(20 mL) was added and the resulting mixture was reduced to half
of its original volume. The resulting solid was isolated by filtration.
Yield: 8 mg (7%). Mp 140 ◦C. IR (KBr pellet, cm−1): m˜ = 3530(br
s), 3120(w), 3052(s), 3034(s), 2996(s), 2963(s), 2925(s), 2839(w),
Preparation of [(L3)Pd2(l-MeCONH)][BPh4]2 (8[BPh4]2)
Method A: To a solution of 4[ClO4]3 (100 mg, 0.105 mmol) in
acetonitrile (10 mL) was added a solution of NaBPh4 (371 mg,
1.08 mmol) in acetonitrile. 5% Aqueous ethanol was added
(20 mL). The product precipitated upon concentration. It was fil-
tered off, washed with ethanol and dried in air. Yield: 85 mg (64%).
Method B: To a hot solution of 3(ClO4)3 (100 mg, 0.105 mmol)
in acetonitrile (30 mL) was added a solution of NaBPh4 (371 mg,
1.08 mmol) in water. The resulting solid was filtered off, washed
with water, and dried over P4O10. Yield: 112 mg (84%). IR (KBr
pellet, cm−1): m˜ = 3435(br s), 3120(w), 3053(w), 3033(s), 2998(s),
=
=
2791(w), 1664(s) m(C N), 1472(s) m(C C), 1438(m), 1425(s),
1405(s), 1392(w), 1364(w), 1338(w), 1327(w), 1224(m), 1179(m),
1161(m), 1121(m), 1105(m), 1075(m), 1065(w), 1032(m), 1021(m),
997(m), 964(w), 951(w), 937(w), 904(w), 891(w), 814(w), 750(m),
732(s) m(BPh4), 707(s) m(BPh4), 612(s). 1H NMR (200 MHz,
acetone-d6): d 1.39 (s, 9 H, tBu), 2.86 (m, 12 H + 4 H, C5H3,
C6H3, C7H2), 4.02 (t, 2 H, 3J = 5.5 Hz, C8H2), 4.08 (t, 2 H, 3J =
5.5 Hz, C8ꢀH2), 6.77 (m, 6 H, BPh4 + PdPh), 6.92 (m, 12 H, BPh4 +
PdPh), 7.33 (m, 12 H, BPh4 + PdPh), 8.19 (s, 2 H, C11H), 8.30 (s,
1 H, C9ꢀH), 8.55 (s, 1 H, C9H). Elemental analysis: calc. (%) for
C56H63BN4Pd2S (1047.84): C 64.19, H 6.06, N 5.35, S 3.06; found:
C 61.77, H 5.94, N 5.09, S 2.62.
=
2982(s), 2929(s), 1639(s) m(C N), 1578(s) m(CONH), 1558(s),
=
1478(s) m(C C), 1458(w), 1426(s) m(CONH), 1396(w), 1365(w),
1337(w), 1230(m), 1182(w), 1148(w), 1101(w), 1077(w), 1032(w),
1000(w), 955(w), 943(w), 908(m), 845(m), 780(s), 733(s) m(BPh4),
705(s) m(BPh4, 610(s).
Preparation of [(L3)Pd2(OAc)][ClO4]2 (9[ClO4]2)
Collection and reduction of X-ray data
To a solution of Nꢀ,Nꢀ-dimethylethane-1,2-diamine (131 mg,
Single crystals of 2[ClO4] and 3[ClO4]2·MeOH were grown by slow
evaporation of methanolic solutions. Crystals of 5[BPh4]·MeCN
were taken directly from the reaction mixture. Crystals of
6[BPh4]·MeCN and 11[BPh4] were grown by slow evaporation
of a mixed acetonitrile–ethanol solvent system. Crystals of
7[ClO4]2·2CH3CH2CN·CH3CN were grown by slow evaporation
of a mixed propionitrile/acetonitrile solvent system. Crystals of
9[ClO4]2 were grown by slow evaporation of a mixed acetone–
methanol solvent system. Crystals of 10[ClO4]2 were grown by
slow evaporation of a mixed chloroacetonitrile–ethanol solvent
system. The crystals were mounted on the tips of glass fibers using
perfluoropolyether oil. All data were collected at 210(2) K, using
a Bruker CCD X-ray diffractometer. Graphite-monochromated
1.49 mmol) in ethanol (30 mL) was added
a solution
of 5-tert-butyl-2-(tert-butylthio)benzene-1,3-dialdehyde (0.20 g,
0.72 mmol) in dichloromethane (15 mL). The solution was stirred
for 24 h after which it was evaporated to dryness. The residue
was redissolved in dichloromethane (20 mL) and combined with a
solution of Pd(OAc)2 (335 mg, 1.49 mmol) in dichloromethane
(20 mL). After the resulting yellow solution was stirred for
further 24 h, a solution of LiClO4·3H2O (1.00 g, 6.24 mmol) in
methanol (50 mL) was added. Evaporation of the solvent gave
a yellow solid, which was filtered off, washed with methanol
and dried in air. Yield: 387 mg (0.460 mmol, 63%). Mp 263 ◦C
(decomp.). IR (KBr pellet, cm−1): m˜ = 3017(w), 2993(s), 2959(s),
˚
=
2943(m), 2911(w), 1643(s) m(C N), 1555(s) mas(OAc), 1457(m),
Mo-Ka radiation (0.71073 A) was used. The data were processed
2124 | Dalton Trans., 2006, 2114–2126
This journal is
The Royal Society of Chemistry 2006
©

View Article Online
with SAINT40 and corrected for absorption using SADABS.41 The
structures were solved by direct methods or by the heavy atom
method (for 3) using the program SHELXS-86.42 Refinements
were carried out by full-matrix least-squares techniques against
F2 using SHELXL-97.43 Platon was used to search for higher
symmetry.44 Drawings were produced with Ortep-3.45 The non-
hydrogen atoms were refined anisotropically. Hydrogen atoms
were assigned to idealized positions and given isotropic thermal
parameters 1.2 times (1.5 times for CH3 groups) the thermal
parameter of the atom to which they were attached. Selected
crystallograpic data are summarized in Table 3.
for X-ray crystallographic measurements. Prof. Dr C. Janiak and
K. Abu-Shandi are thanked for GC-MS measurements.
References
1 J. G. Hughes and R. Robson, Inorg. Chim. Acta, 1979, 35, 87–92.
2 (a) A. J. Atkins, A. J. Blake and M. Schro¨der, J. Chem. Soc., Chem.
Commun., 1993, 1662–1665; (b) N. D. J. Branscombe, A. J. Blake, A.
Marin-Becerra, W.-S. Li, S. Parsons, L. Ruiz-Ramirez and M. Schro¨der,
Chem. Commun., 1996, 2573–2574.
3 N. H. Pilkington and R. Robson, Aust. J. Chem., 1970, 23, 2225–2236.
4 (a) P. A. Vigato, S. Tamburini and D. Fenton, Coord. Chem. Rev., 1990,
106, 25–170; (b) D. Fenton, Chem. Soc. Rev., 1999, 28, 159–168; (c) M.
Yamami, H. Furutachi, T. Yokoyama and H. Okawa, Inorg. Chem.,
1998, 37, 6832–6838; (d) H. Okawa, H. Furutachi and D. E. Fenton,
Coord. Chem. Rev., 1998, 174, 51–75; (e) M. Shinoura, S. Kita, M.
Ohba, H. Okawa, H. Furutachi and M. Suzuki, Inorg. Chem., 2000, 39,
4520–4526.
5 A. J. Atkins, D. Black, A. J. Blake, A. Marin-Becerra, S. Parsons, L.
Ruiz-Ramirez and M. Schro¨der, Chem. Commun., 1996, 457–464.
6 (a) S. Brooker, P. D. Croucher, T. C. Davidson, G. S. Dunbar, A. J.
McQuillan and G. B. Jameson, Chem. Commun., 1998, 2131–2132;
(b) A. C. Marr, D. J. E. Spencer and M. Schro¨der, Coord. Chem. Rev.,
2001, 219–221, 1055–1074.
In the crystal structure of 2[ClO4] one of the
−
CH2CH2NMe2 units and the ClO4 anion were found to
be disordered over two positions. The two CH2CH2NMe2
orientations were refined by using the SADI instruction (equal N–
C and C · · · C distances, respectively) implemented in the ShelXL
program to give site occupancies of 0.55(2) (for C8a–C11a) and
0.45(2) (for C8b–C11b). The disordered C atoms were refined
−
isotropically. The two ClO4 orientations were refined without
constraints to give site occupancies of 0.65(2) (for O1a–O4a)
and 0.35(2) (for O1b–O4b), respectively. The crystal structure
of 3[ClO4]2MeOH revealed the MeOH solvate disordered over
two positions. The site occupancies of the two positions were
refined as follows: O(9a)C(21a)/O(9b)C(21b) 0.62(3)/0.38(3).
The disordered C and O atoms were refined with isotropic thermal
parameters. The Flack parameter (absolute structure parameter)
was calculated to be 0.03(6) (0.97(6) for the inverted structure)
thus providing strong evidence that the absolute structure has
been assigned correctly. In the crystal structure of 5[BPh4]·MeCN
the acetonitrile solvate was found to be disordered over two
positions at site occupancies of 0.42(2) and 0.58(2), respectively.
No hydrogen atoms were calculated for this solvate molecule and
the C and N atoms were refined with isotropic thermal parameters.
In the crystal structure of 7[ClO4]4(EtCN)2(MeCN) one tert-butyl
group was found to be disordered over two positions. A split
atom model was used to account for this disorder. The site
occupancies of the two positions were refined as follows: C(18a)–
C(20A)/C(18b)–C(20b) 0.51(2)/0.49(2). The acetonitrile solvate
was also found to be disordered over two positions. The site occu-
pancies were fixed at 0.50. The C and N atoms of this solvate
molecule were refined with isotropic thermal parameters. In the
crystal structure of 10[ClO4]2 both perchlorates and the tert-butyl
group were found to be disordered. Two split positions were
successfully refined using the SADI instruction (equal Cl–O and
O · · · O or C–C and C · · · C distances, respectively) implemented
in the ShelXL program to give the following site occupancies:
Cl(2)O(3a)–O(5a)O(6)/Cl(2)O(3b)–O(5b)O(6) = 0.36(4)/0.64(4);
Cl(3)O(7a)–O(10a)/Cl(3)O(7b)–O(10b) = 0.57(2)/0.43(2) and
7 C. J. McKenzie and R. Robson, J. Chem. Soc., Chem. Commun., 1988,
112–114.
8 (a) A. L. Gavrilova, C. Jin Qin, R. D. Sommer, A. L. Rheingold and B.
Bosnich, J. Am. Chem. Soc., 2002, 124, 1714–1722; (b) A. L. Gavrilova
and B. Bosnich, Chem. Rev., 2004, 104, 349–383.
9 (a) S. Brooker, Coord. Chem. Rev., 2001, 222, 33–56; (b) S. Brooker,
P. D. Croucher, T. C. Davidson, G. S. Dunbar, C. U. Beck and S.
Subramanian, Eur. J. Inorg. Chem., 2000, 169–179.
10 (a) S. Brooker and P. D. Croucher, J. Chem. Soc., Chem. Commun.,
1995, 1493–1494; (b) S. Brooker and P. D. Croucher, J. Chem. Soc.,
Chem. Commun., 1995, 2075–2076; (c) S. Brooker, P. D. Croucher and
F. M. Roxburgh, J. Chem. Soc., Dalton Trans., 1996, 3031–3037; (d) S.
Brooker and P. D. Croucher, Chem. Commun., 1997, 459–460.
11 (a) T. Beissel, T. Glaser, F. Kesting, K. Wieghardt and B. Nuber, Inorg.
Chem., 1996, 35, 3936–3947; (b) T. Beissel, F. Birkelbach, E. Bill,
T. Glaser, F. Kesting, C. Krebs, T. Weyhermu¨ller, K. Wieghardt, C.
Butzlaff and A. X. Trautwein, J. Am. Chem. Soc., 1996, 118, 12376–
12390; (c) T. Glaser, F. Kesting, T. Beissel, E. Bill, T. Weyhermu¨ller,
W. Meyer-Klaucke and K. Wieghardt, Inorg. Chem., 1999, 38, 722–
732.
12 C. J. McKenzie and R. Robson, Inorg. Chem., 1987, 26, 3615–
3621.
13 E. Bouwman, R. K. Henderson, A. K. Powell, J. Reedijk, W. J. J. Smeets,
A. L. Spek, N. Veldman and S. Wocadlo, J. Chem. Soc., Dalton Trans.,
1998, 3495–3499.
14 G. Siedle and B. Kersting, Z. Anorg. Allg. Chem., 2003, 629, 2083–2090.
15 (a) B. Kersting, Eur. J. Inorg. Chem., 1999, 2157–2166; (b) M. H.
Klingele, G. Steinfeld and B. Kersting, Z. Naturforsch., Teil B, 2001,
56, 901–907.
16 T. E. Crossley, B. F. Hoskins, I. A. S. McDonald and R. Robson, Inorg.
Chim. Acta, 1986, 111, 99–106.
17 R. M. Alcock, F. R. Hartley and D. E. Rogers, J. Chem. Soc., Dalton
Trans., 1973, 1070–1073.
18 P.-K. F. Chin and F. R. Hartley, Inorg. Chem., 1976, 4, 982–984.
19 M. Hesse, H. Meier and B. Zeeh, Spektroskopische Methoden in der
Organischen Chemie, Thieme Verlag, Stuttgart, 1987.
20 K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordina-
tion Compounds, 5th edn, VCH-Wiley, New York, 1997.
21 (a) J. A. Davies, F. R. Hartley and S. G. Murray, Inorg. Chim. Acta,
1980, 41, 249–251; (b) J. A. Davies, F. R. Hartley, S. G. Murray and
M. A. Pierce-Butler, J. Chem. Soc., Dalton Trans., 1983, 1305–1308.
22 M. Louey, C. J. McKenzie and R. Robson, Inorg. Chim. Acta, 1986,
111, 107–111.
C(17)C(18a)–C(20a)/C(17)C(18b)–C(20b)
respectively. The C atoms of the disordered t-Bu group were
refined with isotropic thermal parameters.
=
0.56(2)/0.44(2),
CCDC reference numbers 286854–286861.
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b516071e
23 M. Louey, P. D. Nichols and R. Robson, Inorg. Chim. Acta, 1980, 47,
87–96.
24 B. F. Hoskins, C. J. McKenzie, R. Robson and L. Zhenrong, J. Chem.
Soc., Dalton Trans., 1990, 2637–2641.
Acknowledgements
25 G. Musie, P. J. Farmer, T. Tuntulani, J. H. Reibenspies and M. Y.
Darensbourg, Inorg. Chem., 1996, 35, 2176–2183.
26 B. Kersting, Eur. J. Inorg. Chem., 1998, 1071–1077.
This work was supported by the Deutsche Forschungsgemein-
schaft. We thank Prof. Dr H. Vahrenkamp for providing facilities
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 2114–2126 | 2125
©

View Article Online
27 D. Sellmann, I. Barth, F. Knoch and M. Moll, Inorg. Chem., 1990, 29,
1822–1826.
28 A. J. Blake, A. J. Holder, T. I. Hyde, H.-J. Ku¨ppers, M. Schro¨der, S.
Sto¨tzel and K. Wieghardt, J. Chem. Soc., Chem. Commun., 1989, 1600–
1602.
35 (a) N. B. Pahor, M. Calligaris and L. Randacio, J. Chem. Soc., Dalton
Trans., 1976, 725–730; (b) B. F. Hoskins, C. J. McKenzie and R. Robson,
J. Chem. Soc., Dalton Trans., 1992, 3083–3088.
36 W. Beck, T. M. Klapo¨tke, J. Knizek, H. No¨th and T. Schu¨tt, Eur. J. Inorg.
Chem., 1999, 523–526.
29 J. Becher, H. Toftlund and P. H. Olesen, J. Chem. Soc., Chem. Commun.,
37 V. Y. Kukushkin and A. J. L. Pombeiro, Inorg. Chim. Acta, 2005, 358,
1–21.
1983, 740–742.
30 M. J. Bjerrum, M. Gajhede, E. Larsen and J. Springborg, Inorg. Chem.,
1988, 27, 3960–3964.
31 (a) T. Yamamura, M. Tadokoro and R. Kuroda, Chem. Lett., 1989,
1245–1246; (b) T. Yamamura, M. Tadokoro, M. Hamaguchi and R.
Kuroda, Chem. Lett., 1989, 1481–1484.
38 F. Meyer, E. Kaifer, P. Kircher, K. Heinze and H. Pritzkow, Chem.
Eur. J., 1999, 5, 1617–1630.
39 (a) F. H. Allen, Acta Crystallogr., Sect. B, 2002, 58, 380–388; (b) A. J.
Canty, B. W. Skelton, P. R. Traill and A. H. White, Acta Crystallogr.,
Sect. C, 2004, 60, 305–307.
32 (a) D. Sellmann, K. Engl, T. Gottschalk-Gaudig and F. W. Heinemann,
Eur. J. Inorg. Chem., 1999, 333–339; (b) D. Sellmann, K. Engl, F. W.
Heinemann and J. Sieler, Eur. J. Inorg. Chem., 2000, 1079–1089.
33 Preliminary data of the crystal structure determination of 4[ClO4]3:
40 SAINT+, V6.02, Bruker AXS, Madison, WI, 1999.
41 G. M. Sheldrick, SADABS, Area-Detector Absorption Correction,
University of Go¨ttingen, Go¨ttingen, Germany, 1996.
42 G. M. Sheldrick, Acta Crystallogr., Sect. A, 1990, 46, 467–473.
43 G. M. Sheldrick, SHELXL-97, Computer program for crystal structure
refinement, University of Go¨ttingen, Go¨ttingen, Germany, 1997.
44 A. L. Spek, PLATON- A Multipurpose Crystallographic Tool, Utrecht
University, Utrecht, The Netherlands, 2000.
C24H24Cl3N6O12Pd2S, Mr = 939.70, orthorhombic, space group Pbcn,
3
˚
˚
a = 11.410(2), b = 24.910(5), c = 13.080(3) A, V = 3717.6(13) A , Z =
4, l(Mo-Ka) = 1.30 mm−1, Dc = 1.679 g cm−3, R = 0.0844 for 4635
reflections with (I > 2rI).
34 A. H. Norbury, Adv. Inorg. Chem. Radiochem., 1975, 17, 231–386.
45 L. J. Farrugia, J. Appl. Crystallogr., 1997, 30, 565.
2126 | Dalton Trans., 2006, 2114–2126
This journal is
The Royal Society of Chemistry 2006
©