Allyl palladium dithiocarbamates and related dithiolate complexes as precursors to palladium sulfides

Article abstract of DOI:10.1016/j.jorganchem.2007.02.015

Allyl-palladium dithiocarbamate complexes, [Pd(allyl)(S₂CNR₂)], have been prepared from the addition of dithiocarbamate salts to [Pd(allyl)(μ-Cl)]₂ and TGA and DSC studies have been carried out in order to assess their potential as MOCVD precursors to palladium sulfides. For comparison [(η³-C₄H₇)Pd(S₂PPh₂)] and [Pd(S₂CNMeR)₂] (R = Bu, Hex) have also been prepared and tested as precursors. The unsymmetrical dithiocarbamate complex, [(η³-C₃H₅)Pd(S₂CNMeHex)], which has a melting point of 65 °C was selected as the best single source precursor and thin films of predominantly Pd_2.8S were deposited on glass slides. The crystal structures of [(η³-C₄H₇)Pd(S₂CNMe₂)], [(η³-C₄H₇)Pd(S₂CNPr₂)], [(η³-C₄H₇)Pd(S₂PPh₂)] and [Pd(S₂CNMeBu)₂] are reported. All except [(η³-C₄H₇)Pd(S₂CNPr₂)] show weak intermolecular S?H or Pd?H interactions.

Full text of DOI:10.1016/j.jorganchem.2007.02.015

Journal of Organometallic Chemistry 692 (2007) 2448–2455
www.elsevier.com/locate/jorganchem
Allyl palladium dithiocarbamates and related dithiolate complexes
as precursors to palladium sulfides
a
a
a,
b,
c
*
Anthony Birri , Benjamin Harvey , Graeme Hogarth *, Elif Subasi , Fadime Ugur
˘
a
Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
_
b
Department of Chemistry, Faculty of Science and Arts, Dokuz Eylul University, 35160 Buca, Izmir, Turkey
c
_
Ege University, Faculty of Science, Department of Chemistry, Bornova, 35100 Izmir, Turkey
Received 4 December 2006; received in revised form 9 February 2007; accepted 15 February 2007
Available online 21 February 2007
Abstract
Allyl-palladium dithiocarbamate complexes, [Pd(allyl)(S2CNR2)], have been prepared from the addition of dithiocarbamate salts to
[Pd(allyl)(l-Cl)]2 and TGA and DSC studies have been carried out in order to assess their potential as MOCVD precursors to palladium
sulfides. For comparison [(g3-C4H7)Pd(S2PPh2)] and [Pd(S2CNMeR)2] (R = Bu, Hex) have also been prepared and tested as precursors.
The unsymmetrical dithiocarbamate complex, [(g3-C3H5)Pd(S2CNMeHex)], which has a melting point of 65 ꢀC was selected as the best
single source precursor and thin films of predominantly Pd2.8S were deposited on glass slides. The crystal structures of [(g3-
C4H7)Pd(S2CNMe2)], [(g3-C4H7)Pd(S2CNPr2)], [(g3-C4H7)Pd(S2PPh2)] and [Pd(S2CNMeBu)2] are reported. All except [(g3-
C4H7)Pd(S2CNPr2)] show weak intermolecular SÁ Á ÁH or PdÁ Á ÁH interactions.
ꢁ 2007 Elsevier B.V. All rights reserved.
Keywords: Dithiocarbamate; Palladium; Dithiolate; Allyl; MOCVD; X-ray; TGA; DSC
1. Introduction
(MOCVD) from a single source precursor [5]. In this
manner, thin films of PdS have been prepared by Zink
and co-workers from the xanthate complex [Pd(S2COPri)2],
thermal decomposition at 350 ꢀC producing polycrystalline
tetragonal PdS on both glass slides and silicon wafers [6].
In 2002, O’Brien and co-workers reported the use of
[Pd(S2CNMeHex)2] as a precursor to the formation of thin
films of PdS at 400–500 ꢀC [7], and also prepared trioctyl-
phosphineoxide (TOPO) capped nanoparticles of PdS
upon injecting [Pd(S2CNMeHex)2] in trioctylphosphine
into TOPO at 250 ꢀC.
In our laboratory, we have been interested in developing
volatile precursors for the deposition of palladium metal
and palladium chalcogenides. For the deposition of thin
films of palladium sulfides, we targeted allyl palladium
dithiocarbamate complexes [8,9] since such materials are
easy to prepare and handle and we have previously found
that allyl palladium complexes exhibit relatively high vola-
tility while decomposing cleanly. Herein, we report a com-
parative study of the use of bis(dithiocarbamate) and allyl
A range of palladium sulfides are known including PdS,
PdS2, Pd4S and non-stoichiometric materials such as Pd2.2
S
and Pd2.5S. PdS itself is a semi-conductor (Eg = ꢀ2 eV)
which also finds use in a wide range of catalytic processes
including hydrodesulfurization [1], hydrogenation [2] and
the selective synthesis of methanol from carbon monoxide
and hydrogen [3]. While PdS can easily be prepared upon
addition of hydrogen sulfide to tetrachloropalladate(II),
in common with other metal sulfides it can be difficult to
process or engineer. Jain and co-workers have reported
the formation of Pd4S upon heating thiolate-bridged com-
plexes, [Pd(l-SR)(g3-C4H7)]2 (R = But, Ph, C6F5), in
xylene [4]. A better method of preparing such materials is
to use metal organic chemical vapour deposition
*
Corresponding authors.
E-mail address: g.hogarth@ucl.ac.uk (G. Hogarth).
0022-328X/$ - see front matter ꢁ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.02.015

A. Birri et al. / Journal of Organometallic Chemistry 692 (2007) 2448–2455
2449
Most complexes were isolated as dry solids, varying in
appearance from yellow to red-brown, although a number
were oily. The 1,1,2-trimethyl allyl complexes 3a–3d were
all crystalline solids, however, they were considerably less
volatile than the parent or 2-methyl allyl complexes and
hence not pursued further. The non-substituted allyl com-
plexes 2e–2g were also somewhat less volatile than those
with a single methyl group on the backbone. An attempt
to purify [(g3-C4H7)Pd(S2CNMe2)] (1a) by sublimation
was disappointing. At 130 ꢀC at 1 Torr it sublimed very
slowly and on raising the temperature to 200–230 ꢀC a yel-
low solid was deposited on the probe which was found to
be [Pd(S2CNMe2)2]. Thermal gravimetric analysis (TGA)
and differential scanning calorimetry (DSC) (see later)
showed loss of allyl at around 130 ꢀC, suggesting 1a has
only limited thermal stability.
dithiocarbamate complexes as precursors to palladium
sulfides.
2. Results and discussion
2.1. Synthesis and characterisation
Allyl palladium dithiocarbamate complexes, [Pd(al-
lyl)(S2CNR2)], have previously been prepared in a variety
of ways [8,9]. We adopted the simple approach of Powell
and Chan for their synthesis of [(g3-allyl)Pd(S2CNMe2)]
complexes, namely the addition of two equivalents of
dithiocarbamate salts to allyl palladium chlorides [Pd(al-
lyl)(l-Cl)]2 [8]. Utilizing this simple procedure we prepared
a range of complexes 1–3.
Characterization of complexes was generally straightfor-
ward. All showed absorptions in the IR spectra associated
with the dithiocarbamate and allyl groups, while in the H
R2
R1
S
S
Cl
Cl
2 NaS2CNR1R2
- 2 NaCl
Pd
Pd
N
Pd
1
NMR spectra individual protons were generally clearly
resolved. For example, [(g3-C3H5)Pd(S2CNMeHex)] (2g)
shows a triplet of triplets at d 5.11 for the central allyl pro-
ton, two closely spaced doublets at d 3.98–3.97 associated
with the inequivalent syn protons and a doublet at d 2.71
assigned to the anti protons. The nitrogen-bound methyl
group of the dithiocarbamate appears as a singlet at d
3.28, the adjacent nitrogen-bound methylene group
appearing at d 3.74. Positive ion fast atom bombardment
(FAB) mass spectra were generally quite distinctive. While
most showed molecular ions, these were normally weak
and more abundant heavier ions attributed to [Pd2-
(allyl)2(dithiocarbamate)] and [Pd2(allyl)(dithiocarba-
mate)2] species were observed, suggesting that loss of either
the allyl and/or dithiocarbamate ligands is facile in the gas
phase.
Reactions were carried out in air and work-up proce-
dures were very simple. They proceed in good yield and
are clean provided excess of the dithiocarbamate salts are
not added. If care is not taken in this regard a secondary
process occurs in which the allyl group is displaced by a
dithiocarbamate to give the bis(dithiocarbamate) com-
plexes. The dithiocarbamate salts are generated in metha-
nol and then added to ethereal solutions of the allyl
palladium chlorides. We also attempted to add aqueous
solutions of dithiocarbamate salts to [Pd(allyl)(l-Cl)]2 in
ether but this resulted only in the formation of oily prod-
ucts which were not well-characterized. This is probably
due to the immiscibility of water and ether resulting in poor
control over the reaction stoichiometry. Reactions were
generally carried out on a small scale (ca. 200 mg) and an
attempt to prepare [(g3-C4H7)Pd(S2CNMeHex)] (1g) on a
multi-gram scale gave a disappointing result with the for-
mation of a mixture of this and the bis(dithiocarbamate)
complex [Pd(S2CNMeHex)2] (5b). In separate work we
have shown that bis(dithiocarbamate) complexes result
from the addition of further dithiocarbamate salt to the
allyl complexes and on a larger scale this second process
becomes competitive. This problem can probably be over-
come by the slow addition of the dithiocarbamate salt solu-
tion, although we did not attempt this.
S
S
S
S
R
S
Ph
Ph
Me
R
Pd
N
Pd
N
P
Me
S
a R = Bu
b R = Hex
5a-b
4
Comparison with the allyl dithiocarbamate complexes,
the dithiophosphinate complex [(g3-C4H7)Pd(S2PPh2)] (4)
and two bis(dithiocarbamate) complexes, [Pd(S2CNMeR)2]
(5a–5b) were also prepared. Dithiophospinate 4 was
formed in essentially quantitative yield upon addition of
two equivalents of NaS2PPh2 to [(g3-C4H7)Pd(l-Cl)]2,
while the dithiocarbamate complexes resulted from
addition of two equivalents of in situ generated dithiocar-
bamate salts with Na2[PdCl4] in methanol. The hexyl
complex 5b has previously been reported by O’Brien and
co-workers. Their preparation was carried out in dioxane
and a brown solid resulted. From methanol, both 5a–5b
are orange-yellow solids which become paler upon
R2
R1
S
R2
R1
S
Pd
N
Me
Pd
N
a R1 = R2 = Me
b R1 = R2 = E t
S
S
1a-h
2e-h
c R1 = R2 = Bz
d R1 = R2 = Pr
e R1 = R2 = Bu
f R1 = Me, R2 = B u
g R1 = Me, R2 = Hex
h R1R2 = C5H10
R2
R1
S
Me
Pd
Me
N
S
Me
3a-d

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A. Birri et al. / Journal of Organometallic Chemistry 692 (2007) 2448–2455
sublimation. Characterization of all three was generally
1
straightforward with evidence of fluxionality seen by H
NMR spectroscopy. For [(g3-C4H7)Pd(S2PPh2)] (4), while
resonances associated with the allyl ligand were sharp at
room temperature, all signals in the aromatic region were
broadened significantly. Upon warming to 50 ꢀC these
sharpened to give two multiplets centred at d 7.86 and
7.46. The low-field signal is a doublet of doublets (J 13.7,
6.3) and is attributed to the ortho-protons. We attribute
these changes to the rotation of the allyl ligand which ren-
ders the two phenyl groups equivalent. Room temperature
1H NMR spectra of both 5a–b are deceptively simple. For
5b resonances are generally broad and smaller broad
humps are seen around the major signals. Upon warming
to 50 ꢀC the latter disappear and the major resonances
broaden further. We associate these changes with the
restricted rotation about the backbone carbon–nitrogen
bonds which have some double bond character [10]. The
asymmetric nature of the dithiocarbamates leads to the
possibility of rotational isomers. This has previously been
studied for unsymmetrical palladium(II) bis(dithiocarba-
mate) complexes generated from primary amines by
HPLC. For [Pd(S2CNHCH2CH2Ph)2], a barrier to rota-
tion of 83 5 kJ molÀ1 was measured [11]. Both 5a–5b
Fig. 1. Molecular structure of [(g3-C4H7)Pd(S2CNMe2)] (1a) with selected
bond lengths (A) and angles (ꢀ): Pd–S(1) 2.3653(13), Pd–C(1) 2.154(4), Pd–
C(2) 2.122(6), S(1)–Pd–S(1A) 75.10(6), S(1)–C(4)–S(1A) 111.0(3), C(1)–
Pd–C(1A) 67.5(3).
˚
Fig. 2. Molecular structure of [(g3-C4H7)Pd(S2CNPr2)] (1d) with selected
1
sublimed at 180 ꢀC at 1 Torr to give yellow solids, the H
NMR spectra revealing that the molecules had sublimed
intact.
˚
bond lengths (A) and angles (ꢀ): Pd–S(1) 2.3622(12), Pd–S(2) 2.3787(13),
Pd–C(8) 2.158(4), Pd–C(9) 2.146(4), Pd–C(10) 2.138(4), S(1)–Pd–S(2)
75.23(4), S(1)–C(1)–S(2) 113.7(2), C(8)–Pd–C(9) 67.3(2).
2.2. Structural studies
In order to fully elucidate the structures of all three
types of complex and to determine if there were any inter-
molecular interactions which may affect the volatility of the
complexes, the crystal structures of [(g3-C4H7)Pd-
(S2CNMe2)] (1a), [(g3-C4H7)Pd(S2CNPr2)] (1d), [(g3-C4H7)-
Pd(S2PPh2)] (4) and [Pd(S2CNMeBu)2] (5a) were carried
out, the results of which are displayed in Figs. 1–4 and their
captions. As expected, all contain a square-planar palla-
dium(II) centre. In the allyl complexes this is defined by
the two sulfurs of the dithiocarbamate and the outer car-
bons of the allyl ligand, while in 5a it is defined by the four
sulfurs. In all, the dithiolate and allyl ligands bind approx-
imately symmetrically and geometric parameters are in line
with those for related complexes. Intermolecular interac-
tions are observed in 4 and 5a, long range PdÁ Á ÁH interac-
tions occurring in both (Figs. 3b and 4b). The
bis(dithiocarbamate) complex 5a adopts the transoid con-
figuration and metric parameters are similar to other crys-
tallographically characterized members of this series
[12,13].
Fig. 3a. Molecular structure of [(g3-C4H7)Pd(S2PPh2)] (4) with selected
bond lengths (A) and angles (ꢀ): Pd–S(1) 2.410(2), Pd–S(2) 2.420(2), Pd–
C(1) 2.137(7), Pd–C(2) 2.159(7), Pd–C(3) 2.130(7), Pd–P 2.961(2), S(1)–
˚
Pd–S(2) 84.56(7), S(1)–P–S(2) 107.30(11), C(1)–Pd–C(3) 68.0(3).
2.3. Thermal gravimetric analysis (TGA) and differential
scanning calorimetry (DSC) of potential precursors
for a selection, the results of which are summarized in
Tables 1 and 2. All experiments were carried out under a
nitrogen atmosphere, heating between 20 and 500 ꢀC at a
rate of 10 ꢀC minÀ1. From TGA measurements (Table 1)
the allyl dithiocarbamate complexes (Fig. 5) all showed
two distinct mass losses. The first is consistent with loss
In order to assess the suitability of palladium dithiolate
complexes prepared above for use as single source precur-
sors to palladium sulfides, TGA and DSC were recorded

A. Birri et al. / Journal of Organometallic Chemistry 692 (2007) 2448–2455
2451
of the allyl group, the lability of which was suggested from
their mass spectra. DSC data (Table 2) show that this
change which occurs between 128 and 166 ꢀC is exother-
mic. For three of the complexes this occurs after melting,
as indicated by a prior endothermic change, while for
[(g3-C3H5)Pd(S2CNC5H10)] (2h) the loss occurs in the solid
state. A second mass loss occurs between 320 and 350 ꢀC
for all four complexes and at 350 ꢀC a mass consistent with
the formation of PdS (M = 138) is observed. Continued
heating to 500 ꢀC gives a further gradual mass loss gener-
ally leaving materials with mass intermediate between
PdS and palladium metal (M = 106). The exception to this
is [(g3-C4H7)Pd(S2CNPr2)] (1d) which has a mass of 104 at
500 ꢀC suggesting complete formation of palladium metal.
The allyl palladium dithiophosphinate complex, [(g3-
C4H7)Pd(S2PPh2)] (4), melts at 141 ꢀC. This then shows a
slight exothermic change at 192 ꢀC accompanied by a mass
loss of 8.1%, which may be attributed to loss of the allyl
group. Between 327 and 410 ꢀC there is a further 29% mass
loss, while at 500 ꢀC the compound still has 41% of its ori-
ginal mass. The latter is consistent with the formation of
PdS2 (M = 168). The bis(dithiocarbamate) complexes,
[Pd(S2CNMeR)2] (5a–5b), melt at 147 and 84 ꢀC, respec-
tively. These are low when compared to the melting point
of [Pd(S2CNEt2)2] at 243 ꢀC, although extension of the
alkyl chains such as in [Pd(S2CNBu2)2] reduces this to
109 ꢀC [13]. Up to 300 ꢀC both 5a–b show a steady mass
loss of ca. 10%, while around 380–400 ꢀC both decompose
in a single step to materials with masses consistent with the
formation of palladium sulfide. Franchini and co-workers
have previously shown by TGA that decomposition of
[Pd(S2CNC5H10)2] occurs sequentially to give palladium
sulfides, palladium metal and finally palladium oxide [14].
Their analysis was performed in air, which may account
for the differences observed. O’Brien and co-workers have
previously shown that 5b decomposes to give PdS [7].
Fig. 3b. Molecular structure of [(g3-C4H7)Pd(S2PPh2)] (4) showing
intermolecular interactions; PdÁ Á ÁH(1A) 3.267 A.
˚
2.4. Thin film growth and characterization
Fig. 4a. Molecular structure of [Pd(S2CNMeBu)2] (5a) with selected bond
˚
lengths (A) and angles (ꢀ): Pd–S(1) 2.328(2), Pd–S(2) 2.333(2), S(1)–Pd–
In light of the TGA and DSC results discussed above we
chose [(g3-C3H5)Pd(S2CNMeHex)] (2g) as a potential sin-
gle-source precursor to palladium sulfides. This was based
on its ease of formation and isolation, high level of purity,
low melting point (65 ꢀC) and smooth decomposition in
two steps to leave a material with a mass equivalent to
PdS at 350 ꢀC. Approximately 200 mg of 2g was placed
in the end of a glass tube filled with overlapping glass slides
and evacuated to 10À2 Torr. The complex was then heated
to above its melting point while the centre of the tube was
heated in a furnace at 350 ꢀC. Heating was continued for
1 h resulting in the production of a thin film on two of
the glass slides. The films were silver in appearance and
highly reflective and were not removed from the glass by
adhesive tape. The transmission and reflectance of the film
was probed using UV–Vis light. The film had low transmis-
sion but was highly reflective across the whole spectrum
and no maxima could be found. Energy dispersive X-ray
S(2) 75.36(5).
Fig. 4b. Molecular structure of [Pd(S2CNMeBu)2] (5a) showing intermo-
lecular interactions; PdÁ Á ÁH(3A) 3.131 A.
˚

2452
A. Birri et al. / Journal of Organometallic Chemistry 692 (2007) 2448–2455
Table 1
Summary of TGA data
Complex
MW
First weight loss (%)
(temperature range)
Second weight loss (%)
(temperature range)
wt% residue
(350 ꢀC) (MW)
wt% residue
(500 ꢀC) (MW)
[(g3-C4H7)Pd(S2CNPr2)] (1d)
[(g3-C4H7)Pd(S2CNC5H10)] (1h)
[(g3-C3H5)Pd(S2CNMeHex)] (2g)
[(g3-C3H5)Pd(S2CNC5H10)] (2h)
[(g3-C4H7)Pd(S2PPh2)] (4)
[Pd(S2CNMeBu)2] (5a)
337
321
337
307
410
430
486
19 (112–204)
13 (110–175)
11 (102–167)
10 (102–156)
8 (171–219)
7 (51–281)
37 (255–391)
27 (249–318)
33 (225–336)
31 (256–324)
29 (328–410)
70 (286–427)
68 (309–413)
38 (128)
44 (141)
43 (145)
44 (135)
66 (271)
70 (301)
78 (379)
31 (104)
39 (125)
39 (131)
37 (114)
41 (168)
20 (86)
[Pd(S2CNMeHex)2] (5b)
10 (56–304)
18 (87)
Table 2
Summary of DSC data
primarily Pd2.8S but also amounts of Pd3S, Pd4S, Pd2.2
and Pd2.5S.
S
Complex
Tm (ꢀC)a
Other peaks (ꢀC)
O’Brien and co-workers [7] and Zink and co-workers [6]
have previously used homoleptic palladium dithiocarba-
mate and xanthate complexes, respectively, to prepare thin
films of the tetragonal phase of PdS. Our results are clearly
different to these. Grønvold and Røst have found that the
stoichiometry of palladium sulfide phases is highly temper-
ature dependent [15]. This may account for the difference
between our results and those of O’Brien where formation
of tetragonal PdS from 5b was carried out at 500 ꢀC. Inter-
estingly, deposition of Pd4S from dimeric allyl palladium
dithiolate complexes is reported to occur at 200 ꢀC. The
ratio of palladium:sulfur in the precursor is also likely to
play an important role in the nature of the materials gener-
ated and the 2:1 ratio in [(g3-C3H5)Pd(S2CNMeHex)] (2g)
as compared to 4:1 in [Pd(dithiolate)2] and 1:1 in
[(allyl)Pd(l-SR)]2 may play an important role in determin-
ing the nature of the films formed.
[(g3-C4H7)Pd(S2CNPr2)] (1d)
[(g3-C4H7)Pd(S2CNC5H10)] (1h)
[(g3-C3H5)Pd(S2CNMeHex)] (2g)
[(g3-C3H5)Pd(S2CNC5H10)] (2h)
[(g3-C4H7)Pd(S2PPh2)] (4)
[Pd(S2CNMeBu)2] (5a)
41
92
65
166b
137b 324a
128b 321a
135b 321a
192b 381a
374a
329b
337b
–
141
147
84
[Pd(S2CNMeHex)2] (5b)
402a
a
Endothermic.
Exothermic.
b
TGA
%
100.00
80.00
60.00
40.00
3. Conclusions
We have shown that, provided experimental conditions
are carefully controlled, allyl palladium dithiocarbamate
complexes can be easily prepared in high yields. With suit-
able substituents they have relatively low melting points,
being somewhat lower than the analogous bis(dithiocarba-
mate) complexes. For example the melting points of
[Pd(S2CNMeHex)2] (5b) and [(g3-C3H5)Pd(S2CNMeHex)]
(2g) are 84 and 65 ꢀC, respectively. Further, the allyl dithio-
carbamate complexes readily lose the allyl group upon
heating leading to the formation of a putative ‘‘Pd(dithio-
carbamate)’’ fragment with a palladium:sulfur ratio of 1:2.
This is different to the ratios found in previously employed
precursors to palladium sulfide thin films and appears to
lead to the formation of films with stoichiometries different
to those from other single source precursors. We are cur-
rently investigating their utility in this regard in greater
detail and will report on this in due course.
0.00
100.00
200.00
300.00
400.00
500.00
Temp [C]
Fig. 5. TGA trace for [(g3-C3H5)Pd(S2CNMeHex)] (2g).
spectrometry (EDAX) of the film showed the presence of
both palladium (5.85%) and sulfur (3.00% atomic composi-
tion). A scanning electron micrograph of the palladium sul-
fide film showed the deposited material was crystalline with
an irregular surface and rough edges. A powder X-ray pat-
tern of the film was recorded and matched against palla-
dium sulfide materials held in the database including
Pd4S, Pd3S, Pd2.8S, PdS, PdS2. A poor match to PdS was
seen, but the spectrum matched reasonably well with
Pd2.8S, Pd3S and Pd17S6. The best match was with the
phase Pd2.8S prepared by Grønvold and Røst upon
quenching samples of Pd3S that had been heated to
500 ꢀC [15]. We believe that the film is a mixture containing
4. Experimental
Unless otherwise stated, reactions were carried out in air
in non-dried solvents. Allyl palladium chlorides were pre-
pared following the literature procedures [16] and

A. Birri et al. / Journal of Organometallic Chemistry 692 (2007) 2448–2455
2453
NaS2CNMe2 Æ 3H2O, NaS2CNEt2 Æ 3H2O and NaS2PPh2
were purchased from Aldrich and used as received. IR
spectra were measured as KBr discs using a Perkin–Elmer
1600 Fourier Transform Spectrophotometer. Positive-ion
FAB mass spectra were recorded on a JEOL SX102 mass
spectrometer operated at an accelerating voltage of
10 kV. Samples were desorbed from a nitrobenzyl alcohol
matrix using 3 keV xenon atoms. Elemental analyses were
performed on a Carlo Erba Strummentaione Model 1106
250 (45%), 282 (97%), 337 (27%), 500 (52%), 621 (60%).
Anal. Calc. for Pd1S2N1C11H21: C, 39.17; H, 6.23; N,
4.15. Found: C, 39.54; H, 6.02; N, 4.02%. Single crystals
suitable for diffraction studies were grown upon slow evap-
oration of a saturated diethyl ether solution.
1
[(g3-C4H7)Pd(S2CNBu2)] (1e): oily red solid (69%); H
NMR (CDCl3) d 3.77 (s, 2H, Hsyn), 3.71 (t, J 7.3, 4H,
NCH2), 1.92 (s, 3H, Me), 1.66 (m, 4H, CH2), 1.34 (sextet,
J 7.5, 4H, CH2), 0.90 (t, J 7.2, 6H, Me); FAB MS (+ve) m/z
312 (60%), 528 (91%), 677 (50%).
1
and H and 31P NMR were recorded on a Bruker FX400
spectrometer.
[(g3-C4H7)Pd(S2CNMeBu)] (1f): red oil (76%); 1H
NMR (CDCl3) d 3.77 (m, 4H, NCH2 + Hsyn), 3.30 (s,
3H, NMe), 2.62 (s, 2H, Hanti), 1.92 (s, 3H, Me), 1.64 (m,
2H, NCH2CH2), 1.34 (sex, J 7.6, 2H, NCH2CH2CH2),
0.93 (t, J 7.3, 3H, Me); FAB MS (+ve) m/z 161 (20%),
236 (24%), 268 (94%), 323 (46%), 430 (5%), 486 (32%),
593 (25%).
4.1. Synthesis of[(g3-allyl)Pd(S2CNR1R1)] (1–3)
All complexes were prepared by the same general method
given below except for R1 = R2 = Me, Et where the sodium
dithiocarbamate salts were commercially available and they
were simply dissolved in methanol prior to the reaction.
N-Methylbutylamine (74 mg, 0.85 mmol) was added to a
methanol solution (10 cm3) of NaOH (34 mg, 0.84 mmol).
To this CS2 (65 mg, 0.84 mmol) was added dropwise and
the solution stirred at room temperature for 30 min. A solu-
tion of [(g3-C4H7)Pd(l-Cl)]2 (0.16 g, 0.40 mmol) in diethy-
lether (40 cm3) was added and stirring was continued for
a further 1 h. Removal of volatiles under reduced pressure
gave a brown solid which was dissolved in dichloromethane
(ca. 20 cm3), washed with water (3 · 10 cm3) and dried over
MgSO4. Removal of volatiles gave [(g3-C4H7)Pd(S2CN-
MeBu)] (0.201 g, 76%) as a red oil.
[(g3-C4H7)Pd(S2CNMeHex)] (1g): red oil (82%); 1H
NMR (CDCl3) d 3.71 (m, 4H, NCH2 + Hsyn), 3.27 (s,
3H, NMe), 2.60 (s, 2H, Hanti), 2.08 (s, 3H, Me),1.64 (m,
2H, NCH2CH2), 1.25 (m, 6H, CH2), 0.82 (t, J 6.6, 3H,
Me); FAB MS (+ve) m/z 264 (22%), 296 (100%), 351
(17%), 514 (40%), 617 (18%), 649 (41%), 720 (10%), 752
(18%), 784 (32%).
[(g3-C4H7)Pd(S2CNC5H10)] (1h): purple solid (74%); IR
1
(KBr) 1490vs (CN), 1442m, 1401s, 1244m, 971s (CS); H
NMR (CDCl3) d 3.94 (m, 4H, NCH2), 3.79 (s, 2H, Hsyn),
2.63 (s, 2H, Hanti), 1.92 (s, 3H, Me), 1.67 (m, 6H, CH2);
FAB MS (+ve) m/z 266 (56%), 321 (45%), 426 (10%),
484 (56%), 557 (3%), 589 (25%). Anal. Calc. for
Pd1S2N1C10H17.0.5CH2Cl2: C, 34.56; H, 4.95; N, 3.85.
Found: C, 36.25; H, 5.16; N, 3.73%.
[(g3-C4H7)Pd(S2CNMe2)] (1a): yellow solid (78%); IR
(KBr) 1525vs (CN), 1450m, 1375s, 1350m, 971s (CS); H
1
NMR (CDCl3) d 3.79 (s, 2H, Hsyn), 3.33 (s, 6H, NMe),
2.62 (s, 2H, Hanti), 1.91 (s, 3H, Me); FAB MS (+ve) m/z
161 (13%), 194 (18%), 228 (42%), 281 (25%), 444 (50%),
509 (12%). Anal. Calc. for Pd1S2N1C7H13: C, 29.89; H,
4.63; N, 4.98. Found: C, 29.62; H, 4.01; N, 4.70%. Single
crystals suitable for diffraction studies were grown upon
slow evaporation of a saturated diethyl ether solution.
[(g3-C4H7)Pd(S2CNEt2)] (1b): red solid (76%); IR (KBr)
[(g3-C3H5)Pd(S2CNMeBu)] (2f): brown solid (76%); IR
1
(KBr) 1507vs (CN), 1437m, 1401s, 1299m, 962s (CS); H
NMR (CDCl3) d 5.09 (tt, J 12.6, 6.8, 1H, Hcentral), 3.98
(d, J 6.8, 1H, Hsyn), 3.97 (d, J 6.8, 1H, Hsyn), 3.74 (t, J
7.5, 2H, NCH2), 3.28 (s, 3H, NMe), 2.73 (d, J 12.6, 2H,
H
anti), 1.62 (m, 2H, NCH2CH2), 1.30 (sex, J 7.6, 2H,
NCH2CH2CH2), 0.90 (t, J 7.2, 3H, Me); FAB MS (+ve)
m/z 236 (12%), 268 (31%), 309 (15%), 430 (8%), 579
(6%). Anal. Calc. for Pd1S2N1C9H17.0.25CH2Cl2: C,
33.61; H, 5.30; N, 4.24. Found: C, 33.96; H, 5.21; N, 4.09%.
[(g3-C3H5)Pd(S2CNMeHex)] (2g): brown solid (78%);
IR (KBr) 1517vs (CN), 1461m, 1398s, 1294m, 966s (CS);
1H NMR (CDCl3) d 5.11 (tt, J 12.6, 6.9, 1H, Hcentral),
3.98 (d, J 6.9, 1H, Hsyn), 3.97 (d, J 6.9, 1H, Hsyn), 3.74
(m, 2H, NCH2), 3.28 (s, 3H, NMe), 2.71 (d, J 12.6, 2H,
1
1525vs (CN), 1440m, 1375s, 1350m, 988s (CS); H NMR
(CDCl3) d 3.71 (m, 6H, Hsyn + NCH2), 2.57 (s, 2H, Hanti),
1.87 (s, 3H, Me), 1.22 (t, J 7.1, 6H, Me); FAB MS (+ve) m/z
161 (32%), 222 (42%), 254 (100%), 311 (30%), 472 (72%),
565 (64%). Anal. Calc. for Pd1S2N1C9H17.0.5CH2Cl2: C,
32.40; H, 5.12; N, 3.99. Found: C, 32.09; H, 5.25; N, 4.26%.
[(g3-C4H7)Pd(S2CNBz2)] (1c): yellow solid (65%); IR
1
(KBr) 1500vs (CN), 1430m, 1375s, 1350m, 987s (CS); H
NMR (CDCl3) d 7.35–7.21 (m, 10H, Ph), 4.92 (s, 4H,
CH2Ph), 3.86 (s, 2H, Hsyn), 2.70 (s, 2H, Hanti), 2.15 (s, 3H,
Me); FAB MS (+ve) m/z 221 (15%), 377 (9%), 433 (3%),
595 (10%), 814 (2%). Anal. Calc. for Pd1S2N1C19H21: C,
52.65; H, 4.84; N, 3.23. Found: C, 52.86; H, 4.73; N, 3.02%.
[(g3-C4H7)Pd(S2CNPr2)] (1d): red solid (69%); IR (KBr)
Hanti), 1.66 (m, 2H, NCH2CH2), 1.28 (m, 6H, 3CH2),
0.85 (t, J 6.8, 3H, Me); FAB MS (+ve) m/z 296 (15%),
486 (20%), 635 (4%), 750 (4%), 784 (15%). Anal. Calc.
for Pd1S2N1C11H21.0.5CH2Cl2: C, 36.36; H, 5.80; N,
3.69. Found: C, 37.24; H, 5.81; N, 3.68%.
[(g3-C3H5)Pd(S2CNC5H10)] (2h): purple solid (69%); IR
1
1
1525vs (CN), 1435m, 1375s, 1350m, 970s (CS); H NMR
(KBr) 1503vs (CN), 1439m, 1284m, 973s (CS); H NMR
(CDCl3) d 3.77 (s, 2H, Hsyn), 3.67 (t, J 7.8, 4H, NCH2),
2.62 (s, 2H, Hanti), 1.92 (s, 3H, Me), 1.73 (m, 4H, CH2),
0.92 (t, J 7.8, 6H, Me); FAB MS (+ve) m/z 161 (21%),
(CDCl3) d 5.13 (tt, J 12.6, 7.0, 1H, Hcentral), 4.04 (d, J
7.0, 2H, Hsyn), 3.96 (m, 4H, NCH2), 2.74 (d, J 12.6, 2H,
H
anti), 1.67 (m, 6H, CH2); FAB MS (+ve) m/z 426 (33%),

2454
A. Birri et al. / Journal of Organometallic Chemistry 692 (2007) 2448–2455
575 (17%). Anal. Calc. for Pd1S2N1C9H15.0.5CH2Cl2: C,
32.62; H, 4.58; N, 4.01. Found: C, 33.62; H, 4.53; N, 4.05%.
[(g3-C6H11)Pd(S2CNMe2)] (3a): brown solid (80%); IR
was added Na2PdCl4 Æ 3H2O (0.04 g, 0.32 mmol). A
yellow precipitate immediately formed and this was
stirred for 1 h. After filtration the solid was washed with
water (3 · 10 cm3) and methanol (10 cm3) and air-dried
to give [Pd(S2CNMeBu)2] (0.12 g, 87%) as a yellow-
orange solid. 1H NMR (CDCl3) d 3.68 (t, J 7.6, 4H,
NCH2), 3.24 (s, 6H, NMe), 1.63 (tt, J 9.2, 7.4, 4H,
CH2), 1.37 (sextet, J 7.4, 4H, CH2), 0.95 (t, J 7.4, 6H,
Me). Anal. Calc. for Pd1S4N2C12H24: C, 33.45; H, 5.58;
N, 6.50. Found: C, 34.14; H, 5.76; N, 6.44%. Single
crystals suitable for diffraction studies were grown upon
slow evaporation of a dichloromethane–diethyl ether
solution.
1
(KBr) 1520vs (CN), 1450m, 1395s, 1360m, 970s (CS); H
NMR (CDCl3) d 3.64 (br, 1H, Hsyn), 3.35 (s, 6H, NMe),
2.94 (br, 1H, Hanti), 1.93 (s, 3H, Me), 1.67 (s, 3H, Me),
1.33 (s, 3H, Me); FAB MS (+ve) m/z 226 (18%), 311
(10%), 416 (25%), 500 (100%), 537 (13%). Anal. Calc. for
Pd1S2N1C9H17: C, 34.68; H, 5.78; N, 4.50. Found: C,
34.44; H, 5.70; N, 4.75%.
[(g3-C6H11)Pd(S2CNEt2)] (3b): brown solid (82%); IR
1
(KBr) 1505vs (CN), 1450m, 1425s, 1365m, 989s (CS); H
NMR (CDCl3) d 3.75–3.70 (m, 4H, NCH2), 3.60 (s, 1H,
H
syn), 2.84 (s, 2H, Hanti), 1.88 (s, 3H, Me), 1.64 (s, 3H,
Me), 1.29 (s, 3H, Me), 1.20 (t, J 7.0, 6H, Me); FAB MS
(+ve) m/z 154 (12%), 222 (33%), 254 (40%), 337 (21%),
402 (20%), 528 (100%). Anal. Calc. for Pd1S2N1C9H17: C,
39.17; H, 6.23; N, 4.15. Found: C, 38.54; H, 6.21; N, 3.68%.
[(g3-C6H11)Pd(S2CNBz2)] (3c): brown solid (60%); IR
4.4. [Pd(S2CNMeHex)2] (5b)
Prepared as above using HNMeHex to give a yellow-
1
orange solid in 90% yield. H NMR (CDCl3) (328 K) d
3.69 (brt, J 7.5, 4H, NCH2), 3.25 (s, 6H, NMe), 1.69 (m,
4H, CH2), 1.33 (br, 12H, CH2), 0.90 (t, J 7.4, 6H, Me).
Anal. Calc. for Pd1S4N2C16H32: C, 39.47; H, 6.61; N,
5.78. Found: C, 39.33; H, 6.67; N, 5.57%.
1
(KBr) 1500vs (CN), 1455m, 1375s, 1350m, 987s (CS); H
NMR (CDCl3) d 7.43–7.32 (m, 10H, Ph), 5.03–5.00 (br,
4H, CH2Ph), 3.82 (s, 1H, Hsyn), 3.08 (s, 1H, Hanti), 2.07
(s, 3H, Me), 1.84 (s, 3H, Me), 1.51 (s, 3H, Me); FAB MS
(+ve) m/z 198 (100%), 346 (37%), 461 (8%), 652 (20%),
841 (43%). Anal. Calc. for Pd1S2N1C21H25: C, 54.60; H,
5.42; N, 3.03. Found: C, 54.49; H, 5.40; N, 3.07%.
4.5. PdS
Hydrogen sulfide was bubbled through an aqueous solu-
tion (20 cm3) of Na2PdCl4 (1.00 g, 2.87 mmol) for 5 min.
The solution was then stirred for a further 30 min resulting
in the formation of a fine black precipitate. This was
allowed to settle, collected by filtration and air-dried to
give PdS as a black precipitate.
[(g3-C6H11)Pd(S2CNPr2)] (3d): brown solid (74%); IR
1
(KBr) 1500vs (CN), 1435m, 1375s, 1345m, 971s (CS); H
NMR (CDCl3) d 3.69 (q, J 6.0, 4H, NCH2), 3.66 (s, 1H,
H
syn), 2.92 (s, 1H, Hanti), 1.96 (s, 3H, Me), 1.74 (m, 4H,
CH2), 1.72 (s, 3H, Me), 1.37 (s, 3H, Me), 0.96 (t, J 7.8,
3H, Me), 0.92 (t, J 7.8, 3H, Me); FAB MS (+ve) m/z 144
(100%), 282 (46%), 365 (22%), 472 (10%), 556 (47%), 649
(43%). Anal. Calc. for Pd1S2N1C13H25: C, 42.74; H, 6.85;
N, 3.83. Found: C, 42.24; H, 6.69; N, 3.44%.
4.6. X-ray data collection and solution
Single crystals were mounted on glass fibres and all geo-
metric and intensity data were taken from these samples
using an automated four-circle diffractometer (Nicolet
4.2. Synthesis of [(g3-C4H7)Pd(S2PPh2)] (4)
˚
R3mV) equipped with Mo Ka radiation (k = 0.710 73 A)
A methanol solution (10 cm3) of NaS2PPh2 (0.136 g,
0.50 mmol) was added to a diethylether (40 cm3) solution
of [(g3-C4H7)Pd(l-Cl)]2(0.10 g, 0.25 mmol) in diethylether
(40 cm3). This was stirred for 1h resulting in the formation
of a dark red precipitate. After filtration, washing with
water (2 · 10 cm3) and methanol (10 cm3) gave a dark red
solid which was air-dried to give [(g3-C4H7)Pd(S2PPh2)]
(0.195 g, 95%). 1H NMR (CDCl3) d 7.80 (br, 4H, Ph),
7.45 (br, 6H, Ph), 3.83 (s, 2H, Hsyn), 2.75 (s, 2H, Hanti),
1.97 (s, 3H, Me); 31P NMR (CDCl3) d 89.2 (s). Anal. Calc.
for Pd1S2N1C16H17: C, 46.78; H, 4.14. Found: C, 46.62; H,
4.29%. Single crystals suitable for diffraction studies were
grown upon slow evaporation of a saturated diethyl ether
solution.
at 293 2 K. Lattice parameters were identified by appli-
cation of the automatic indexing routine of the diffractom-
eter to the positions of a number of reflections taken from a
rotation photograph and centred by the diffractometer.
The x–2h (1a, 1c, 4) or x techniques (5a) were used to mea-
sure reflections and three standard reflections (remeasured
every 97 scans) showed no significant loss in intensity dur-
ing data collections. The data were corrected for Lorenz
and polarisation effects and unique data with I P 2r(I)
were used to solve and refine the structures. These were
solved by direct methods and developed by using alternat-
ing cycles of least-squares refinement and difference-Fou-
rier synthesis. All non-hydrogen atoms were refined
anisotropically. Hydrogen atoms were placed in idealised
˚
positions (C–H 0.96 A) and assigned a common isotropic
2
˚
4.3. Synthesis of [Pd(S2CNMeBu)2] (5a)
thermal parameter (U = 0.08 A ). Final difference-Fourier
map was featureless and contained no peaks greater than
A methanol solution (10 cm3) of NaS2CNMeBu (ca.
0.64 mmol) was prepared as described above. To this
1.00 e AÀ3. Structure solution used SHELXTL PLUS program
˚
package on an IBM PC.

A. Birri et al. / Journal of Organometallic Chemistry 692 (2007) 2448–2455
2455
Crystallographic data for [(g3-C4H7)Pd(S2CNMe2)] (1a):
orange needle, dimensions 0.45 · 0.16 · 0.06 mm, mono-
Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit
@ccdc.cam.ac.uk. Supplementary data associated with this
article can be found, in the online version, at doi:10.1016/
j.jorganchem.2007.02.015.
˚
˚
clinic, space group P21/m, a = 5.291(1) A, b = 10.576(2) A,
3
˚
˚
c = 9.109(2) A, b = 92.83(3)ꢀ, V = 509.1(2) A , Z = 2,
F(000) = 280, dcalc = 1.838 g cmÀ3, l = 2.173 mmÀ1. 1179
reflections were collected, 1057 unique [Rint = 0.0347] of
which 977 were observed [I > 2.0r(I)]. At convergence,
R1 = 0.0387, wR2 = 0.1013 [I > 2.0r(I)] and R1 = 0.0415,
wR2 = 0.1046 (all data), for 61 parameters.
References
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A. Ermakova, A.V. Mashkina, L.G. Sakhaltueva, Kinet. Catal. 43
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Crystallographic data for [(g3-C4H7)Pd(S2CNPr2)] (1d):
pale yellow block, dimensions 0.80 · 0.24 · 0.22 mm, tri-
˚
˚
ꢀ
clinic, space group P1, a = 8.619(2) A, b = 9.373(2) A,
˚
c = 9.800(2) A,
a = 97.59(3)ꢀ,
b = 109.10(3)ꢀ,
c =
=
3
˚
89.86(3)ꢀ, V = 740.9(3) A , Z = 2, F(000) = 344, dcalc
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1.514 g cmÀ3, l = 1.507 mmÀ1. 2789 reflections were
collected, 2599 unique [Rint = 0.0244] of which 2594 were
observed [I > 2.0r(I)]. At convergence, R1 = 0.0357,
wR2 = 0.0884 [I > 2.0r(I)] and R1 = 0.0408, wR2 = 0.1044
(all data), for 136 parameters.
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Crystallographic data for [(g3-C4H7)Pd(S2PPh2)] (4):
pale yellow plate, dimensions 0.46 · 0.42 · 0.06 mm,
˚
monoclinic, space group P21/c, a = 8.838(2) A, b =
˚
˚
12.494(2) A, c = 15.459(3) A, b = 94.60(3)ꢀ, V = 1701.5
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(6) A , Z = 4, F(000) = 824, dcalc = 1.604 g cmÀ3, l =
3
˚
1.417 mmÀ1. 3151 reflections were collected, 2952 unique
[Rint = 0.0413] of which 2943 were observed [I > 2.0r(I)].
At convergence, R1 = 0.0486, wR2 = 0.1111 [I > 2.0r(I)]
and R1 = 0.0728, wR2 = 0.5534 (all data), for 181
parameters.
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Crystallographic data for [Pd(S2CNMeBu)2] (5a):
orange block, dimensions 0.43 · 0.40 · 0.27 mm, hexago-
ꢀ
˚
˚
nal, space group R3, a = b = 25.654(4) A, c = 7.135(1) A,
3
˚
V = 4066.6(11) A ,
Z = 9,
F(000) = 1980,
dcalc =
1.584 g cmÀ3, l = 1.478 mmÀ1. 925 reflections were col-
lected, 917 unique [Rint = 0.0136] of which 908 were
observed [I > 2.0r(I)]. At convergence, R1 = 0.0317,
wR2 = 0.0720 [I > 2.0r(I)] and R1 = 0.0447, wR2 = 0.0885
(all data), for 88 parameters.
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Acknowledgements
We thank AEA Technology for partial funding of this
work and Mr. Mark Shilton for his interest, TUBITAK-
BAYG for funding the visit of ES to UCL, Professor Ivan
Parkin and Dr. Anne Newport for making powder X-ray
measurements of the palladium sulfide sample, Dr. Mari-
anne Odlyha for TGA and DSC measurements and Mr.
Kevin Reeves for scanning electron microscopy.
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Appendix A. Supplementary material
CCDC 628659, 628660, 628661 and 628662 contain the
supplementary crystallographic data for this paper. These
data can be obtained free of charge via http://www.ccdc.
cam.ac.uk/conts/retrieving.html, or from the Cambridge
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