Syntheses, displacement behavior, hetero-atom carbene, and crystal structures of platinum complexes containing the N,N-dimethylthiocarbamoyl, Me2NC{double bond, long}S, ligand

Article abstract of DOI:10.1016/j.jorganchem.2006.06.001

In solution state, the complex [Pt(PPh₃)₂(η¹-SCNMe ₂)(Cl )] (1) shows intermolecular displacement of two triphenylphosphine ligands to form the bridging η²-thiocarbamoyl diplatinum complex [Pt(PPh₃)Cl]₂(μ,η²-SCNMe ₂)₂ (2). Intramolecular displacement of the chloride product η²-thiocarbamoyl complex [Pt(PPh₃)₂(η²-SCNMe₂)][C l] (3) was not been detected from the ³¹P{¹H} NMR experiments. However, the chelating η²-thiocarbamoyl complex [Pt(PPh₃)₂(η²-SCNMe₂)][P F₆] (4) can be produced by the reaction of 1 with NH₄PF₆ in acetone at ambient temperature. Treatment of 1 with dppa {bis(diphenylphosphino)amine} in dichloromethane at room temperature results in the formation of the complex [Pt(PPh₃)(η²-dppa){η¹-C(S) NMe₂}][Cl] (5). Treatment of 4 with EtOCS₂K or MeOCS₂K yields Fischer-type carbene-complex [Pt(PPh₃){η¹-C(SEt)(NMe₂)} (η²-S₂CO)] (7) or [Pt(PPh₃){η¹-C(SMe)(NMe₂)} (η²-S₂CO)] (8). The carbene-complexes 7 and 8 are formed via alkyl migration of the alkyldithiocarbonate ligand to the thiocarbamoyl ligand. Complex 1 reacts with EtOCS₂K, resulting in the formation of the η²-dithiocarbonate complex [Pt(PPh₃)(η¹-SCNMe₂) (η²-S₂COEt)] (6) and the carbene-complex[Pt(PPh₃){η¹-C(SEt) (NMe₂)}(η²-S₂CO)] (7) with a ratio of 3:2 according to the integration of the ³¹P{¹H} NMR spectra. By continuously stirring mixtures 6 and 7 in the CH₂Cl₂ solution for 4 h, complex 7 was formed as the final product. All of the complexes were identified by spectroscopic methods and complexes 2, 5, and 7 were determined by single-crystal X-ray diffraction.

Full text of DOI:10.1016/j.jorganchem.2006.06.001

Journal of Organometallic Chemistry 691 (2006) 3997–4005
www.elsevier.com/locate/jorganchem
Syntheses, displacement behavior, hetero-atom carbene, and
crystal structures of platinum complexes containing the
N,N-dimethylthiocarbamoyl, Me2NC@S, ligand: Structures
of [Pt(PPh3)(Cl)]2(l,g2-SCNMe2)2, [Pt(PPh3)(g2-dppa)-
{g1-C(S)NMe2}][Cl], and [Pt(PPh3)2{g1-C(SEt)(NMe2)}(g2-S2CO)]
a,
b
Kuang-Hway Yih *, Gene-Hsiang Lee
a
Department of Applied Cosmetology, Hungkuang University, Shalu, Taichung 433, Taiwan, Republic of China
b
Instrumentation Center, College of Science, National Taiwan University, Taiwan
Received 27 April 2006; received in revised form 24 May 2006; accepted 1 June 2006
Available online 10 June 2006
Abstract
In solution state, the complex [Pt(PPh3)2(g1-SCNMe2)(Cl)] (1) shows intermolecular displacement of two triphenylphosphine ligands
to form the bridging g2-thiocarbamoyl diplatinum complex [Pt(PPh3)Cl]2(l,g2-SCNMe2)2 (2). Intramolecular displacement of the chlo-
ride product g2-thiocarbamoyl complex [Pt(PPh3)2(g2-SCNMe2)][Cl] (3) was not been detected from the 31P{1H} NMR experiments.
However, the chelating g2-thiocarbamoyl complex [Pt(PPh3)2(g2-SCNMe2)][PF6] (4) can be produced by the reaction of 1 with NH4PF6
in acetone at ambient temperature. Treatment of 1 with dppa {bis(diphenylphosphino)amine} in dichloromethane at room temperature
results in the formation of the complex [Pt(PPh3)(g2-dppa){g1-C(S)NMe2}][Cl] (5). Treatment of 4 with EtOCS2K or MeOCS2K yields
Fischer-type carbene-complex [Pt(PPh3){g1-C(SEt)(NMe2)}(g2-S2CO)] (7) or [Pt(PPh3){g1-C(SMe)(NMe2)}(g2-S2CO)] (8). The car-
bene-complexes 7 and 8 are formed via alkyl migration of the alkyldithiocarbonate ligand to the thiocarbamoyl ligand. Complex 1 reacts
with EtOCS2K, resulting in the formation of the g2-dithiocarbonate complex [Pt(PPh3)(g1-SCNMe2)(g2-S2COEt)] (6) and the carbene-
complex [Pt(PPh3){g1-C(SEt)(NMe2)}(g2-S2CO)] (7) with a ratio of 3:2 according to the integration of the 31P{1H} NMR spectra. By
continuously stirring mixtures 6 and 7 in the CH2Cl2 solution for 4 h, complex 7 was formed as the final product. All of the complexes
were identified by spectroscopic methods and complexes 2, 5, and 7 were determined by single-crystal X-ray diffraction.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Platinum; N,N-D imethylthiocarbamoyl ligand; Carbene; Ethyldithiocarbonate ligand; Crystal structures
1. Introduction
reaction of metal carbonylates with N,N-dimethylthiocar-
bamoyl chloride, Me2NC(@S)Cl, via nucleophilic displace-
ment of chloride [6], nucleophilic attack by an amine on an
electrophilic thiocarbonyl complex [7], electrophilic attack
at a coordinated isothiocyanate [8], reaction of hydrosul-
fide with haloaminocarbene [9] or isonitrile [10] ligands,
cleavage of a dithiocarbamate ligand [2], or C–H activation
of thioformamides [11]. Oxidative addition [4] of both chlo-
ride and N,N-dimethylthiocarbamoyl ligand to the metal
complex is most generally used and is relevant to the work
described herein.
Although thiocarbamoyl metal complexes are known in
Nb, Ta (VB) [1], Mo, W (VIB) [2,3], Ru, Rh, and Ir (VIIIB)
[4,5], the Pt thiocarbamoyl complex has received little
attention. These complexes have been prepared from the
*
Corresponding author. Tel.: +886 4 26318652 1200; fax: +886 4
26310579.
E-mail address: khyih@sunrise.hk.edu.tw (K.-H. Yih).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.06.001

3998
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 691 (2006) 3997–4005
Our previous report showed that the sulfur atom of the
phate, NH4PF6, in acetone with 92% isolated yield at
ambient temperature [14]. The yellow-orange complex 4 is
more stable and is less soluble than that of 1. In the Pd ana-
log, complex [Pd(PPh3)2(g1-SCNMe2)(Cl)], showing the
inter- and intramolecular displacement behavior, was shown
to form complexes [Pd(PPh3)Cl]2(l,g2-SCNMe2)2 and
[Pd(PPh3)2(g2-SCNMe2)][Cl] [12] and the displacement of
either the phosphine or the chloride ligand occurred in
CH2Cl2 solution of complex [Pd(PPh3)2(g1-CH2SCH3)Cl]
[15] to form monomer complexes [Pd(PPh3)(g2-
CH2SCH3)Cl] and [Pd(PPh3)2(g2-CH2SCH3)][Cl]. It is plau-
sible that the sulfur atom of the thiocarbamoyl ligand assists
triphenylphosphine displacement of 1 to form 2.
thiocarbamoyl ligand assists the displacement of either the
chloride or the triphenylphosphine ligand to form the g2-
thiocarbamoyl palladium complexes [12]. We report here
the formation of two hetero-atom carbene complexes of
the platinum via alkyl migration of the alkyldithiocarbon-
ate to thiocarbamoyl ligand, as well as the displacement
behavior and reactions of [Pt(PPh3)2(g1-SCNMe2)(Cl)]
(1) with neutral phosphorus ligand. Three X-ray crystal
structure analyses have been carried out to provide struc-
tural parameters.
2. Results and discussion
In the reaction of 1 with dppa {bis(diphenylphosph-
ino)amine in dichloromethane at room temperature, a
chloride and triphenylphosphine were displaced, forming
complex [Pt(PPh3)(g2-dppa){g1-C(S)NMe2}][Cl] (5) with
88% isolated yield.
2.1. Syntheses
We have previously reported the reaction of Pt(PPh3)4
with N,N-dimethylthiocarbamoyl chloride, Me2NC(@S)Cl,
in dichloromethane at ꢀ20 ꢁC, yielding the air-stable yel-
low complex [Pt(PPh3)2(g1-SCNMe2)(Cl)] (1) [13].
Nucleophilic displacement of the chloride in 1 with
anionic dithiocarbonate ligand, EtOCSꢀ2 , in dichloro-
methane at room temperature produces complex [Pt(PPh3)-
(g1-SCNMe2)(g2-S2COEt)] (6) and carbene-complex
[Pt(PPh3)- {g1-C(SEt)(NMe2)}(g2-S2CO)] (7) in good yields
and 31P{1H} NMR spectrum indicates the 3:2 ratio of 6 and
7. The dichloromethane solution of the mixtures 6 and 7
slowly undergo the ethyl-thiocarbamoyl coupling reaction
of 6 to give 7 as the final product with 78% isolate yield over
4 h at room temperature. The same procedure was used to
prepare the other carbene-complex [Pt(PPh3){g1-C(SMe)-
(NMe2)}(g2-S2CO)] (8) with 85% isolated yield. The conver-
sion of complex 6 to carbene complex 7 is proposed to
The dichloromethane solution of 1 undergoes intermolec-
ular displacement of the triphenylphosphine ligand of 1 to
form the bridging g2-thiocarbamoyl diplatinum complex
[Pt(PPh3)Cl]2(l,g2-SCNMe2)2 (2) but the intramolecular
displacement of the chloride ligand of 1 to form the chelating
g2-thiocarbamoyl complex [Pt(PPh3)2(g2-SCNMe2)][Cl] (3)
has not been found (Scheme 1). Continuous refluxing of the
chloroform solution of these mixtures for 8 h produces com-
plex 2 as the final product with 93% isolated yield (Fig. 1).
Complex [Pt(PPh3)2(g2-SCNMe2)][PF6] (4) can be synthe-
sized from the reaction of 1 and ammonium hexafluorophos-
Cl
PPh3
PPh3
Cl
Ph3P
C
Pt
2PPh3
+
Pt
S
PPh3
Cl
Pt
C
NMe2
C
3
S
Me2N
S
2
intermolecular
dissociation
NMe2
CH2Cl2, r.t.
EtOCS2K
CH2Cl2, r.t.
O
C
Cl
S
Et
+ 7
PPh3
PPh3
Ph3P
Me2NC(S)Cl
Pt
Pt
S
Ph3P
PPh3
S
Pt
CH2Cl2,-20oC
C
Me2N
C
Me2N
Ph3P
PPh3
S
1
6
3:2
dppa
CH2Cl2
r.t., 1h
CH2Cl2, r.t., 4h
acetone
r.t., 20min
NH4PF6
Ph2P
Pt
NH
O
S
C
Cl
PPh3
PPh3
Ph3P
Ph3P
PPh2
Pt
EtOCS2K
S
Pt
S
C
Me2N
C
Me2N
7
Et
C
MeOH, r.t., 4h
PF6
S
S
5
NMe2
4
O
S
C
MeOCS2K
Ph3P
Pt
S
MeOH, r.t., 4h
C
Me2N
Me
S
8
Scheme 1.

K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 691 (2006) 3997–4005
3999
Cl
Cl
PPh3
Cl
intermolecular
dissociation
Ph3P
Pt
2PPh
+
3
Pt
S
Ph3P
PPh3
Pt
C
NMe2
C
C
Me2N
S
Me2N
S
1
2
Fig. 1. Refluxing-temperature 1H NMR spectra of the mixtures 1 and 2 in CDCl3
( is the diethyl ether).
*
proceed via (path c) sulfur atom of the thiocarbamoyl ligand
of 6 to attack the ethyl group of the ethyldithiocarbonate
ligand of another complex 6 to form 7 (Scheme 2). The for-
mation of 7 from the reaction of 4 with potassium ethyldi-
thiocarbonate is proposed to proceed via (path a) the
anionic ethyldithiocarbonate ligand to attack cationic Pt
complex 4 to form the intermediate 60, followed by the for-
mation of chelating ethyldithiocarbonate ligand with releas-
ing one PPh3 ligand to form 6 and then underwent path c to
form 7 or via (path b) the intermediate complex 600 process-
ing intramolecular ethyl abstraction inducing the chelating
dithiocarbonate ligand with releasing one PPh3 ligand to
form the carbene complex 7.
The air-stable yellow-orange compounds 7 and 8 are sol-
uble in polar solvent, and insoluble in diethyl ether and n-
hexane. Complexes 7 and 8 both include a dithiocarbonate
group, S2CO2ꢀ. Dithiocarbonate metal complexes have
previously been prepared by a variety of synthetic routes
O
S
C
Et
Ph3P
Pt
S
C
Me 2N
6
S
O
Et
S
C
Ph3P
Pt
S
S
S
C
Me2N
6
c
C
S
Et
O
PPh3
O
Pt
PPh3
S
C
Et
S
Ph3P
C
Pt
S
O
S
C
6
NMe2
C
Me2N
Ph3P
Pt
S
6'
S
S
C
Me2N
7
Et
a
S
S
K
S
C
b
O
EtOC
S
PPh3
S
Pt
PPh3
Et
PPh3
S
C
Pt
PPh3
NMe2
C
PF6
NMe2
4
6"
Scheme 2.

4000
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 691 (2006) 3997–4005
including reactions of metal carbonyl sulfide complexes
with COS [16], reactions of metal carbon disulfide com-
plexes with dioxygen [17], and dealkylation [18], iodide
abstraction [19], and hydrolysis [20] of alkoxydithiocarba-
mate metal complexes. Syntheses of carbene complexes
by the reaction of Pt thiocarbamoyl and thio ester com-
plexes with electrophiles have been reported [21]. To our
knowledge, our discussion here of the formation of dithio-
carbonate carbene-complex from the alkyl-thiocarbamoyl
coupling reaction is the first example in the literature.
The isolated compounds 2, 4–8 were already of good
purity, but analytically pure samples could be obtained
by slow n-hexane diffusion into a dichloromethane solution
at +4 ꢁC. All characterization data are consistent with the
proposed constitution.
2.3. NMR spectroscopy
After refluxing 1 in CDCl3 for 2 h, the 1H NMR spectra
of 1 clearly showed four methyl resonances for the mixtures
of 1 and the diplatinum complex [Pt(PPh3)Cl]2(l,g2-
SCNMe2)2 (2) (Fig. 1). Two methyl resonances of the
1
SCNMe2 ligand are observed in the H NMR spectra of
complexes 2, 4–8, consistent with hindered rotation about
the partially multiple C–N bond. The 13C{1H} NMR spec-
tra of the methyl signals of complexes 2, 4–8 are in the
region from d 39.8 to d 54.0. The low-field sections of the
13C{1H} NMR spectra consist of one resonance attribut-
able on intensity grounds to the thiocarbamoyl carbon
1
atom in the region from d 213.6 to d 233.8. In the H
NMR spectra of 8 and 7, one resonance at d 2.82 and
two resonances at d 1.26 and d 4.07, together with their cor-
responding 13C{1H} NMR signals at d 21.8 and at d 13.7, d
39.8, are attributed to the S–CH3 [23a] and the S–CH2CH3
[23b] groups, respectively. The 13C{1H} NMR spectra of 7
and 8 reveal two doublets (9.2, 9.5 Hz) at the lowest field,
which are assigned to the carbon atoms of the carbene (d
226.5 and d 229.8) and dithiocarbonate (d 194.4 and d
195.5) carbon nuclei, respectively.
2.2. IR and MS spectroscopy
In the infrared spectra of 5 and 6, the C–N stretches for
the SCNMe2 group are in the region of 1429–1437 cmꢀ1
,
typical for a g1-bound SCNMe2 group [22] with partially
multiple C–N bond of the thiocarbamoyl ligand. The peaks
at 1520 and 1526 cmꢀ1 in the IR spectra of 7 and 8 indicate
a delocalized C(SR)NMe2 group. The IR spectra of 7 and 8
show the C@O stretching band of the coordinated carbon-
ate ligand at 1680, 1612 and at 1683, 1618 cmꢀ1, respec-
tively, which are indicative of a chelate dithiocarbonate
ligand [16–20]. The FAB mass spectra of 6–8 show parent
peaks with the typical Pt isotope distribution correspond-
ing to [M+] molecular masses, respectively. In the FAB
mass spectra, base peaks with the typical Pt isotope distri-
bution are respectively in agreement with the [M+ ꢀ Cl]
molecular masses of 2 and 5.
The 31P{1H} NMR spectrum of 4 shows two doublet res-
onances at d 16.3 and d 22.7 with satellites (JPt–P = 1525,
JPt–P = 2097 Hz) due to the 195Pt nuclei, and so the relative
downfield resonance compared to those of 1 (d 15.9), 2 (d
9.51), 7 (d 15.5), and 8 (d 15.4) shows the cationic character
of 4. From this description, it is clear that the compound 4 is
side-on bound through the C–S moiety of the SCNMe2
ligand. The 31P{1H} NMR spectrum of 5 shows two broad
multiplet resonances at d 13.3 and d 16.1 with satellites
(JPt–P = 1417, JPt–P = 729 Hz) with 2:1 ratios.
Fig. 2. An ORTEP drawing with 50% thermal ellipsoids and atom-numbering scheme for the complex [Pt(PPh3)Cl]2(l,g2-SCNMe2)2 (2).

K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 691 (2006) 3997–4005
4001
Fig. 4. An ORTEP drawing with 30% thermal ellipsoids and atom-
numbering scheme for the complex [Pt(PPh3){g1-C(SEt)(NMe2)}(g2-
S2CO)] (7).
Fig. 3. An ORTEP drawing with 50% thermal ellipsoids and atom-
numbering scheme for the cationic complex [Pt(PPh3)(g2-dppa){g1-
C(S)NMe2}][Cl] (5).
with atom labels of 2, 5, and 7 are shown in Figs. 2–4.
Crystal data and refinement details and selected inter-
atomic distances (A) and angles (ꢁ) of complexes 2, 5,
and 7 are listed in Tables 1 and 2, respectively.
Complex 2 is a dimer with each SCNMe2 unit bridging
through carbon atoms of the thiocarbamoyl group to one
platinum metal center and sulfur atom to the other plati-
num, forming a six-membered ring with boat-form geome-
try. These geometries are consistent with the significant
2.4. X-ray single-crystal structures of 2, 5, and 7
˚
To confirm the thiocarbamoyl platinum and the
ethyl-thiocarbamoyl coupling carbene-complex, the afore-
mentioned compounds 2, 5, and 7 were examined by sin-
gle-crystal X-ray diffraction studies. Single crystals of the
three complexes were grown by slow n-hexane diffusion
into a dichloromethane solution at +4 ꢁC. ORTEP plots
Table 1
Crystal data and refinement details for complexes 2 Æ CH2Cl2, 5 Æ 2CH2Cl2, and 7 Æ H2O
2 Æ CH2Cl2
5 Æ 2CH2Cl2
7 Æ H2O
Chemical formula
Formula weight
Crystal system
Space group
C
43H44Cl4N2P2S2Pt2
C47H46Cl5N2P3SPt
1136.17
Monoclinic
Cc
C24H28NO2PS3Pt
684.71
Monoclinic
P21/n
12.4263(6)
17.3026(9)
12.5437(6)
90
92.564(1)
90
2694.3(2)
4
1246.84
Triclinic
ꢀ
P1
˚
a (A)
9.8523(3)
11.4246(4)
20.7734(7)
104.499(1)
94.639(1)
105.226(1)
2157.22(12)
2
1.920
6.931
0.71073
150(1)
14.7638(7)
37.9156(18)
9.7706(4)
90
120.477(1)
90
4715.1(4)
4
1.601
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
qcalcd (g cmꢀ3
)
1.688
5.520
0.71073
295(2)
l(Mo Ka) (mmꢀ1
)
3.441
0.71073
150(1)
˚
k (A)
T (K)
h Range (ꢁ)
1.03–27.50
9862
496
0.026
0.058
1.07–27.50
10246
532
0.043
0.085
2.01–27.50
6191
289
0.037
0.100
Independent reflections
Number of variables
Ra
b
Rw
Sc
1.031
0.986
1.075
P
P
a
b
c
R = ||Fo| ꢀ |Fc||/ |Fo|.
P
Rw = [ w(|Fo| ꢀ |Fc|)2]1/2; w = 1/s2(|Fo|).
P
Quality-of-fit = [ w(|Fo| ꢀ |Fc|)2/(Nobserved ꢀ Nparameters)]1/2
.

4002
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 691 (2006) 3997–4005
Table 2
˚
Selected interatomic distances (A) and angles (ꢁ) for 2, 5, and 7
Cl
PPh3
O
Cl
S
C
Ph3P
Ph2P
Pt
NH
Pt
Pt
Ph3P
Pt
Cl
S
C
NMe2
Ph3P
PPh2
C
C
Me2N
S
Me2N
S
2
7
C
SEt
Me2N
5
S
Pt–P
2.2716(10) 2.2691(10)
2.2973(18)
2.3211(19)
2.3320(18)
2.059(7)
2.2698(13)
2.012(6)
Pt–CS
Pt–S
1.965(4), 1.975(4)
2.3481(10)
2.3647(9)
–
2.3325(16) 2.3336(15)
C@S
1.739(4), 1.726(4)
1.679(7)
1.762(6), 1.726(7)
1.707(7)
C–N
1.318(5), 1.324(5)
1.307(9)
1.347(9)
N–Me
1.471(5), 1.463(5)
1.463(5), 1.464(5)
1.445(10), 1.477(9)
1.523(12), 1.485(10)
C–Pt–X (Cl,P,S)
Pt–C–S
178.29(11), 178.44(12)
117.3(2), 118.4(2)
162.89(19)
109.9(4)
169.97(19)
124.5(4)
partial double bond character in the C–S and SC–N bonds
of the SCNMe2 ligands. Thus, the C–S bond distances
(1.739(4) and 1.726(4) A) are comparable to the C–S dou-
the empty P orbital of C(2) atom. The Pt–S(1) (2.3325(16)
˚
˚
A) and Pt–S(2) (2.3336(15) A) bond distances are within
˚
˚
the normal Pt–S length range (2.23–2.32 A) [25]. The bond
ble bond in ethylenethiourea, although they are longer than
distances within the dithiocarbonate ligand, S–C(av),
˚
˚
˚
those in free CS2 (1.554 A). The SC–N bond distances
1.762(7) A, and C(1)–O(1), 1.212(7) A, fall in the range of
values found for other dithiocarbonate complexes; and they
are indicative of an overall electronic delocalization within
the S2CO group [16].
˚
(1.318(5) and 1.324(5) A) are typical for a C–N bond hav-
ing partial double bond character, and are certainly much
˚
shorter than the normal C–N (1.47 A) single bond.
In complex 5, the SCNMe2 ligand is r bound to the Pt
atom through the carbon atom of the thiocarbamoyl
group. The S–Pt bond distance of 3.096 A in 5 indicates
2.5. Conclusion
˚
that there is no bonding interaction between the sulfur
atom and platinum metal atom. The platinum atom has
a distorted square planar geometry. One of the phosphorus
atom of the dppa ligand is trans to the triphenylphosphine
ligand: P(3)–Pt–P(1), 168.35(7)ꢁ, while the other is trans to
the carbon atom of the thiocarbamoyl ligand: P(2)–Pt–
C(1), 162.89(19)ꢁ.
In this article we report the syntheses, dissociation
behavior and X-ray crystal structures of thiocarbamoyl
Pt complexes. These observations confirm that the sulfur
atom of the thiocarbamoyl ligand assists in the displace-
ment of the triphenylphosphine ligand to form a diplati-
num complex 2. The bridging thiocarbamoyl dinuclear
complex [Pt(PPh3)Cl]2(l,g2-SCNMe2)2 (2), including a
six-membered ring, is an organometallic dinuclear com-
pound. A novel alkyl-thiocarbamoyl coupling reaction
produces the N,S-hetero-atom carbene-complexes 7 and
8 from the reaction of 1 with alkyldithiocarbonate
ligands. Two important factors in forming the carbene-
In complex 7, the platinum atom has a distorted square
planar geometry and the carbene carbon, Pt, S, and N all
˚
are coplanar to within 0.0093 A. Three bond angles of
C(2) (120.9ꢁ, 124.5ꢁ, and 114.6ꢁ) clearly show the sp2
character of the carbon. One of the sulfur atoms of dithio-
carbonate ligand is trans to the triphenylphosphine: S(2)–
Pt–P(1), 171.27(5)ꢁ, while the other is trans to the carbene
ligand: S(1)–Pt–C(2), 169.97(19)ꢁ. The Pt–C(2) bond dis-
complexes are (1) the
p
interaction between the
carbene-carbon and SR or NMe2 and (2) the greater che-
lation ability of the dithiocarbonate ligand than the
alkyldithiocarbonate ligand. Three bonding modes of
the thiocarbamoyl ligand are observed: (1) monodentate
coordination through carbon atom (complexes 5 and 6),
(2) bidentate through carbon and sulfur atoms by chela-
tion (complex 4) and (3) bridging between two metal cen-
ters (complex 2).
II
˚
tance, 2.012(6) A, is longer than the other Pt –carbon-
(carbonyl) distances, and similar to those of Pt–C(carbene)
distances [24]. Within the carbene C(SMe)(NMe2), the
geometry is consistent with significant partial double bond
˚
character in the S(3)–C(2) (1.707(7) A) and C(2)–N(1)
˚
(1.347(9) A) bonds. This implies Pp–Pp overlap, involving

K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 691 (2006) 3997–4005
4003
3. Experimental
vacuum and n-hexane (10 ml) was added to initiate precip-
itation. The yellow-orange solids 4 were formed which were
isolated by filtration (G4), washed with n-hexane
(2 · 10 ml) and subsequently dried under vacuum yielding
[Pt(PPh3)2(g2-SCNMe2)][PF6], 4 (0.88 g, 92%). Further
purification was accomplished by recrystallization from
1/10 CH2Cl2/n-hexane. Spectroscopic data of 4 are as fol-
lows. IR (KBr, cmꢀ1) m(CN) 1476(m), 1432(m); m(PF6)
837(vs). 1H NMR (500 MHz, CDCl3, 298 K): d 2.35,
3.57 (s, 6H, NCH3), 7.24–7.46 (m, 35H, Ph). 31P{1H}
NMR (202 MHz, CDCl3, 298 K): d 16.3, 22.7 (d, PPh3,
2JP–P = 11, JPt–P = 1525, JPt–P = 2097), ꢀ143.9 (sep, PF6,
JP–F = 713). 13C{1H} NMR (125 MHz, CDCl3, 298 K): d
3.1. Materials
All manipulations were performed under nitrogen using
vacuum-line, drybox, and standard Schlenk techniques.
NMR spectra were recorded on a Bruker AM-500 WB
FT-NMR spectrometer and are reported in units of d
(ppm) with residual protons in the solvent as an internal
standard (CDCl3, d 7.24). IR spectra were measured on a
Nicolate Avator-320 instrument and were referenced to a
polystyrene standard, using cells equipped with calcium
fluoride windows. Mass spectra were recorded on a JEOL
SX-102A spectrometer. Solvents were dried and deoxygen-
ated by refluxing over the appropriate reagents before use.
n-Hexane, diethyl ether, THF and benzene were distilled
from sodium-benzophenone. Acetonitrile and dichloro-
methane were distilled from calcium hydride. Methanol
was distilled from magnesium. All other solvents and
reagents were of reagent grade and were used as received.
Elemental analyses and X-ray diffraction studies were
carried out at the Regional Center of Analytical Instru-
mentation located at the National Taiwan University.
PtCl2 Æ xH2O was purchased from Strem Chemical,
EtOCS2K, dppa, and NH4PF6 were purchased from
Merck.
4
46.3, 54.0 (d, NCH3, JP–C = 6.19), 129.3–134.8 (m, C of
2
Ph), 216.2 (d, CS, JP–C = 6.2). MS (FAB, NBA, m/z):
807.3 [M+ ꢀ PF6], 719.3 [M+ ꢀ PF6 ꢀ CSNMe2], 545.1
[M+ ꢀ PF6 ꢀ PPh3]. Anal. Calc. for C39H36F6NP3SPt: C,
49.16; H, 3.81; N, 1.47. Found: C, 49.28; H, 4.06; N,
1.51%.
3.4. [{g2-Bis(triphenylphosphino)amine}(g1-N,N-
dimethylthiocarbamoyl)(triphenylphosphine) platinum(II)]
[chloride] (5)
CH2Cl2 (40 mL) was added to a flask (100 mL) contain-
ing [Pt(PPh3)2(g1-SCNMe2)(Cl)] (1) (0.843 g, 1.0 mmol)
and dppa (0.384 g, 1.0 mmol) and the solution was stirred
at room temperature. After stirring 1 h, MeOH (10 mL)
was added to the solution and the brown solids were
formed which were isolated by filtration (G4), washed with
n-hexane (2 · 10 ml) and subsequently dried under vacuum
3.2. Bis-[(chlorotriphenylphosphine)][l-bis-{g2-N,N-
dimethylthiocarbamoyl}] platinum(II) (2)
CHCl3 (20 ml) was added to a flask (100 ml) containing
[Pt(PPh3)2(g1-SCNMe2)(Cl)] (1) [13b] (0.843 g, 1.0 mmol).
The solution was refluxed for 8 h then diethyl ether
(30 ml) was added to the solution and a yellow precipitate
was formed. The precipitate was collected by filtration (G4)
washed with n-hexane (2 · 10 ml) and then dried in vacuo
yielding 0.54 g (93%) of 2. Spectroscopy for2: IR (KBr,
yielding
0.85 g
(88%)
of
[Pt(g1-SCNMe2)(g2-
dppa)(PPh3)][Cl] (5). IR (KBr, cmꢀ1) m(CN) 1470(m),
1429(m). 1H NMR (500 MHz, CDCl3 298 K): d 2.58,
2.81 (s, 6H, NCH3), 7.14–7.76 (m, 30H, Ph). 31P{1H}
NMR (202 MHz, CDCl3, 298 K): d 13.3 (m, dppa,
JPt–P = 1417), 16.1 (m, PPh3, JPt–P = 729). 13C{1H} NMR
(125 MHz, CDCl3, 298 K): d 40.3, 45.7 (d, NCH3,
4JP–C = 4.53), 128.2–137.2 (m, C of Ph), 225.5 (s, CS).
MS (FAB, NBA, m/z): 930.4 [M+ ꢀ Cl], 842.4
[M+ ꢀ Cl ꢀ SCNMe2]. Anal. Calc. for C45H42ClN2P3SPt:
C, 55.93; H, 4.38; N, 2.90. Found: C, 56.04; H, 4.46; N,
3.08%.
cmꢀ1
)
m(CN) 1481(m), 1435(m). 31P{1H} NMR
(202 MHz, CDCl3, 298 K): d 9.51 (s, PPh3, JPt–P
=
1826 Hz). 1H NMR (500 MHz, CDCl3, 298 K): d 2.48,
3.27 (s, 6H, NCH3), 7.28–7.80 (m, 30H, Ph). 13C{1H}
NMR (125 MHz, CDCl3, 298 K): d 39.8, 48.7 (s, NCH3),
127.8–135.3 (m, C of Ph), 213.6 (s, CS). MS (FAB, NBA,
m/z): 1125 [M+ ꢀ Cl]. Anal. Calc. for C42H42Cl2N2P2S2Pt2:
C, 43.41; H, 3.64; N, 2.41. Found: C, 43.28; H, 3.58; N,
2.20%.
3.5. [(g2-Ethyldithiocarbonate)(g1-N,N-dimethylthio-
carbamoyl)(triphenylphosphine) platinum(II)] (6)
3.3. [(Bis(triphenylphosphine) (g2-N,N-dimethylthio-
carbamoyl) platinum(II)) [hexafluorophosphate] (4)
IR (KBr, cmꢀ1) m(CN) 1475(m), 1437(m). 1H NMR
(500 MHz, CDCl3 298 K): d 1.35 (t, 3H, OCH2CH3,
JH–H = 4.7), 2.95, 3.22 (s, 6H, 2NCH3), 4.07 (q, 2H,
OCH2, JH–H = 4.7), 7.17–7.75 (m, 15H, Ph). 31P{1H}
Acetone (20 ml) was added to a flask (100 ml) contain-
ing NH4PF6 (0.163 g, 1.0 mmol) and [Pt(PPh3)2(g1-
SCNMe2)(Cl)] (1) (0.843 g, 1.0 mmol). The solution was
stirred for 20 min at room temperature. The solvent was
then removed under vacuum. The remaining solid was dis-
solved in 10 ml of CH2Cl2 and the solution was filtered to
remove excess NH4Cl. The solution is concentrated under
NMR (202 MHz, CDCl3 298 K):
d 11.2 (s, PPh3,
JPt–P = 2128). 13C{1H} NMR (125 MHz, CDCl3 298 K):
d 31.5 (s, OCH2CH3), 39.8, 48.9 (s, NCH3, JPt–C = 17.4,
47.1), 68.7 (s, OCH2), 128.2–134.4 (m, C of Ph), 194.4
(s, S2CO), 233.8 (s, NCSEt). MS (FAB, NBA, m/z): 667
[M+].

4004
K.-H. Yih, G.-H. Lee / Journal of Organometallic Chemistry 691 (2006) 3997–4005
3.6. [(g2-Dithiocarbonate)(g1-N,N-dimethylthioethyl-
carbene)(triphenylphosphine) platinum(II)] (7)
A suitable single crystal of 2 was mounted on the top of
a glass fiber with glue. Initial lattice parameters were deter-
mined from 24 accurately centered reflections with h values
in the range from 1.03ꢁ to 27.50ꢁ. Cell constants and other
pertinent data were collected and are recorded in Table 1.
Reflection data were collected using the h/2h scan method.
Three check reflections were measure every 30 min
throughout the data collection and showed no apparent
decay. The merging of equivalent and duplicate reflections
gave a total of 28150 unique measured data, of which 9862
reflections with I > 2r(I) were considered observed. The
first step of the structure solution used the heavy-atom
method (Patterson synthesis), which revealed the positions
of metal atoms. The remaining atoms were found in a series
of alternating difference Fourier maps and least-squares
refinements. The quantity minimized by the least-squares
program was w(|Fo| ꢀ |Fc|)2, where w is the weight of a
given operation. The analytical forms of the scattering fac-
tor tables for the neutral atoms were used [27]. The non-
hydrogen atoms were refined anisotropically. Hydrogen
atoms were included in the structure factor calculations
in their expected positions on the basis of idealized bonding
geometry but were not refined in least squares. All hydro-
MeOH (10 mL) was added to a flask (100 mL) contain-
ing [Pt(PPh3)2(g2-SCNMe2)][PF6] (4) (0.952 g, 1.0 mmol)
and EtOCS2K (0.160 g, 1.0 mmol) at room temperature.
After stirring for 4 h, the yellow-orange precipitate was
formed. The precipitate was collected by filtration (G4),
washed with n-hexane (2 · 10 mL) and then dried in vacuo
to yield 0.52 g (78%) of complex [Pt(PPh3){g1-C(SEt)(N-
Me2)}(g2-S2CO)] (7). IR (KBr, cmꢀ1) m(CO) 1680(vs),
1
1612(vs). H NMR (500 MHz, CDCl3 298 K): d 1.26 (t,
3H, SCH2CH3, JH–H = 7.1), 2.82, 3.48 (s, 6H, 2NCH3),
4.07 (q, 2H, SCH2, JH–H = 7.1), 7.37–7.86 (m, 15H, Ph).
31P{1H} NMR (202 MHz, CDCl3 298 K): d 15.5 (s, PPh3,
JPt–P = 1625). 13C{1H} NMR (125 MHz, CDCl3 298 K):
d 13.7 (s, SCH2CH3, JPt–C = 47.1), 39.8 (s, SCH2, JPt–C
=
17.4), 43.8, 51.8 (s, NCH3, JPt–C = 17.4, 32.4), 128.2–
134.4 (m, C of Ph), 194.4 (s, S2CO), 226.5 (d, NCSEt,
JP–C = 9.2). MS (FAB, NBA, m/z): 667 [M+]. Anal. Calc.
for C24H26NOPS3Pt: C, 43.23; H, 3.93; N, 2.10. Found:
C, 43.35; H, 4.08; N, 2.02%.
3.7. [(g2-Dithiocarbonate)(g1-N,N-dimethylthiomethyl-
carbene)(triphenylphosphine) platinum(II)] (8)
gens were assigned isotropic thermal parameters 1–2 A
2
˚
larger then the equivalent Biso value of the atom to which
they were bonded. The final residuals of this refinement
were R = 0.026 and Rw = 0.058.
The procedures for 5 and 7 were similar to those for 2.
The final residuals of this refinement were R = 0.043 and
Rw = 0.085 for 5, and R = 0.037 and Rw = 0.100 for 7.
Selected bond distances and angles are listed in Table 2.
X-ray crystallographic files, in CIF format, for the struc-
tures of complexes 2, 5, and 7 are given in supplementary
material.
The synthesis and work-up were similar to those used in
the preparation of complex 7. The complex [Pt(PPh3){g1-
C(SMe)(NMe2)}(g2-S2CO)] (8) was isolated in 85% yield
as a yellow-orange microcrystalline solid. IR (KBr, cmꢀ1
)
m(CO) 1683(vs), 1618(vs). 1H NMR (500 MHz, CDCl3
298 K): d 2.82 (s, 3H, SCH3), 2.93, 3.49 (s, 6H, 2NCH3),
7.28–7.76 (m, 15H, Ph). 31P{1H} NMR (202 MHz, CDCl3
298 K): d 15.4 (s, PPh3, JPt–P = 1662). 13C{1H} NMR
(125 MHz, CDCl3 298 K): d 21.8 (s, SCH3, JPt–C = 34.5),
43.2, 51.2 (s, NCH3, JPt–C = 17.5, 30.8), 128.1–137.2 (m,
C of Ph), 195.5 (s, S2CO), 229.8 (d, NCSMe, JP–C = 9.5).
MS (FAB, NBA, m/z): 653 [M+]. Anal. Calc. for
C23H24NOPS3Pt: C, 42.32; H, 3.71; N, 2.15. Found: C,
42.48; H, 3.80; N, 2.01%.
Acknowledgements
We thank the National Science Council of Taiwan, the
Republic of China (NSC94-2113-241-001) for support
and Mrs. S.-L. Huang for carrying out NMR experiments.
Appendix A. Supplementary data
3.8. X-ray crystallography
Supplementary data associated with this article can
be found, in the online version, at doi:10.1016/j.jorgan-
chem.2006.06.001.
3.8.1. Single-crystal X-ray diffraction analyses of 2, 5, and 7
Single crystals of 2, 5, and 7 suitable for X-ray diffrac-
tion analyses were grown by recrystallization from 20/1
n-hexane/CH2Cl2. The diffraction data were collected at
room temperature on an Enraf-Nonius CAD4 diffractome-
ter equipped with graphite-monochromated Mo Ka
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