Pyridine-2-thionate as a versatile ligand in Pd(ii) and Pt(ii) chemistry: The presence of three different co-ordination modes in [Pd2(μ 2-S,N-C5H4SN)(μ2- κ2S-C5H4SN)(μ2-dppm) (S-C5H4SN)2]

Article abstract of DOI:10.1039/b508438e

Reactions of [MCl₂(L-L)], M = Pt, Pd; L-L = bis(diphenylphosphino)methane (dppm) or bis(diphenylphosphino)ethane (dppe), with NaC₅H₄SN in a 1: 2 molar ratio lead to mononuclear species [M(S-C₅H₄SN)₂(P-P)], M = Pt; L-L = dppm (1) or dppe (2) and M = Pd; L-L = dppe (3), as well as to the dinuclear [Pd₂(μ₂-S,N-C₅H₄SN) (μ₂-κ²S-C₅H₄SN) (μ₂-dppm)(S-C₅H₄SN)₂] (4). In contrast, reaction of [MCl₂(dppm)] with NaC₅H ₄SN in a 1: 1 molar ratio leads to [Pd₂(μ₂- S,N-C₅H₄SN)₃(μ₂-dppm)]Cl (5) and trans-[Pt(S-C₅H₄SN)₂(PPh₂Me) ₂] (6) respectively. The latter is formed in low yield by cleavage of the dppm ligand. The dinuclear derivatives 4 and 5 present an A-frame and lantern structure, respectively. The former showing three different co-ordination modes in the same molecule with a short Pd-Pd distance of 2.9583 (9) A and the latter with three bridging S,N thionate ligands showing a shorter Pd-Pd distance of 2.7291 (13) A. Both distances could be imposed by the bridging ligands or point to some sort of metal-metal interaction. The Royal Society of Chemistry 2006.

Full text of DOI:10.1039/b508438e

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www.rsc.org/dalton | Dalton Transactions
Pyridine-2-thionate as a versatile ligand in Pd(II) and Pt(II) chemistry:
the presence of three different co-ordination modes in
[Pd2(l2-S,N-C5H4SN)(l2-j2S-C5H4SN)(l2-dppm)(S-C5H4SN)2]
Ara´nzazu Mend´ıa,*a Elena Cerrada,b Francisco J. Arna´iza and Mariano Laguna*b
Received 14th June 2005, Accepted 15th September 2005
First published as an Advance Article on the web 28th October 2005
DOI: 10.1039/b508438e
Reactions of [MCl2(L–L)], M = Pt, Pd; L–L = bis(diphenylphosphino)methane (dppm) or
bis(diphenylphosphino)ethane (dppe), with NaC5H4SN in a 1 : 2 molar ratio lead to mononuclear
species [M(S-C5H4SN)2(P–P)], M = Pt; L–L = dppm (1) or dppe (2) and M = Pd; L–L = dppe (3), as
well as to the dinuclear [Pd2(l2-S,N-C5H4SN)(l2-j2S-C5H4SN)(l2-dppm)(S-C5H4SN)2] (4). In contrast,
reaction of [MCl2(dppm)] with NaC5H4SN in a 1 : 1 molar ratio leads to [Pd2(l2-S,N-C5H4SN)3-
(l2-dppm)]Cl (5) and trans-[Pt(S-C5H4SN)2(PPh2Me)2] (6) respectively. The latter is formed in low yield
by cleavage of the dppm ligand. The dinuclear derivatives 4 and 5 present an A-frame and lantern
structure, respectively. The former showing three different co-ordination modes in the same molecule
˚
with a short Pd–Pd distance of 2.9583 (9) A and the latter with three bridging S,N thionate ligands
˚
showing a shorter Pd–Pd distance of 2.7291 (13) A. Both distances could be imposed by the bridging
ligands or point to some sort of metal–metal interaction.
(M = Pd, Pt; L = PPh3,19,20 L2 = dppe21), [MCl(C5H4SN)(PPh3)],
Introduction
[M(C5H4SN)2(PPh3)] (M = Pd, Pt),19 [PdCl(C5H4SN)(PPh3)2]19 or
[{PdCl(S,N)(PMe3)}2] (S,N = C5H4SN,22 C4H3N2S, C4(Me)H2SN2
and C3H2SN(Me)N23) or [Pd(S,N)(L)2][ClO4]24 with S,N =
C5H4SN, C4H3SN2, C3H3SN2, C3H2SN2CH3, C3H2S2N and L =
PPh3 or L2 = dppe, were prepared. The procedures used are ox-
idative addition reaction of dipyridyl-2,2ꢀ-disulfide to [M(PPh3)4],
metathesis replacement of chlorine from [Pd(l-Cl)Cl(PPh3)]2,
[MCl(C5H4SN)(PPh3)] and [Pd(l-Cl)Cl(PMe3)]2, and deprotona-
tion of the corresponding thione through the l-hydroxo anion of
the precursor24 [{Pd(l-OH)2(L)2}2][ClO4]2.
Compounds containing heterocyclic thione and/or thionate
groups linked to one or more metallic centres have been known
for several decades. However, in the last decade they have
provoked more interest1–5 due to their wide range of appli-
cations. In general, the presence of metal thiolates in bio-
logical systems,6–8 their application as fungicides,8,9 as electric
conductors10,11 and in the pharmaceutical industry,9,12–14 includ-
ing the anticarcinogenic properties15,16 of some complexes with
platinum and gold, have been responsible for, among other
aspects, raising the interest in heterocyclic thiones and thion-
ates as a source of sulfur donor ligands. The co-ordination
chemistry of heterocyclic thiones and their corresponding anions
as ligands is very rich, combining a soft and hard end which
can be interesting for catalytic applications. Therefore, termi-
nal S-bonding or N-bonding, S-bridging, N,S-chelating, N,S-
bridging, N,S-chelation-cum-S-bridging or N,S-bridging-cum-S-
bridging modes are found in the literature.1–5 Structural studies
show that binuclear complexes containing bridging heterocyclic
thionate ligands are the most represented. However, in contrast
with the large number of complexes based on two bridging
ligands that have been reported, there are only two examples
of three bridging co-ordination modes to date, that is, [NaV(l2-
j2S,jN-C5H4SN)3(S,N-C5H4SN)(thf)2]17 and [Ru2(l2-j2S,jN-
C5H4SN)2(l2-S,N-C5H4SN)(S,N-C5H4SN)2][CF3SO3],18 the latter
being the only reported example of coexistence of three different
co-ordination modes of pyridine-2-thionate in the same complex.
With regard to the chemistry of palladium and platinum mono-
nuclear complexes with the general formula [M(C5H4SN)2(L)2]
In this paper we describe the reactions of sodium pyridine-
2-thionate with [MCl2(L–L)] (M = Pd, Pt and L–L = dppm,
dppe) in a 2 : 1 or 1 : 1 molar ratio showing different behaviours
depending on the metal, ligand or reactive molar ratios. With
dppe—independent of metal and conditions—only disubstituted
[M(C5H4SN)2(dppe)] (2, 3) complexes are obtained. However, with
the dppm derivatives, complexes [Pd2(C5H4SN)4(dppm)] (4) and
[Pd2(C5H4SN)3(dppm)]Cl (5), or [Pt(C5H4SN)2(dppm)] (1) were
obtained. The X-ray structures confirm the mononuclear nature
of 1 and in the case of dinuclear complexes 4 and 5 show an
A-frame structure for the former and a lantern structure for the
latter. In addition complex 4 shows an unprecedented combination
of three different modes of co-ordination of pyridine-2-thionate
in the same complex.
Experimental
Chemicals
Pyridine-2-thione (C5H5SN) (Aldrich), Na (Aldrich), dppm, dppe
or PPh2Me (Aldrich) were used as received. Platinum and PdCl2
were procured from INCOMETAL, S.A. Reagent grade diethyl
ether, hexane or dichloromethane were dried using standard
a
´
Departamento de Qu´ımica, Area de Qu´ımica Inorga´nica, Facultad de
Ciencias, Universidad de Burgos, 09001, Burgos, Spain
bDepartamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales
de Arago´n, Universidad de Zaragoza-C.S.I.C., 50009, Zaragoza, Spain
This journal is
The Royal Society of Chemistry 2006
Dalton Trans., 2006, 609–616 | 609
©

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procedures and freshly distilled immediately before use. Absolute
ethanol was deoxygenated with an N2 purge. The complexes
[PtCl2(dppm)], [PtCl2(dppe)], [PdCl2(dppm)] and [PdCl2(dppe)]
were prepared by adding the appropriate diphosphine ligand to a
solution of [PtCl2(COD)] or [PdCl2(NCPh)2]. These two reagents
were prepared by literature routes or slight variations thereof.25
All starting manipulations were carried out under a nitrogen
atmosphere using Schlenk line and syringe techniques.26
0.386 mmol) and C5H5SN (43.0 mg, 0.386 mmol) in absolute
CH3CH2OH (20 mL)—was added to a suspension of [PtCl2(dppe)]
(128.5 mg, 0.193 mmol) in absolute CH3CH2OH (20 mL) under an
inert atmosphere. A lemon yellow solution appeared immediately
and slowly became totally clear. After stirring for 5 h at room
temperature, the solution was concentrated to ca. 5 mL under
vacuum and hexane was added (20 mL). The pale yellow solid
precipitate was isolated by filtration and obtained in 75% yield.
Anal. Calcd for C36H32PtN2P2S2: C, 53.13; H, 3.96; N, 3.44; S, 7.88.
Found: C, 52.83; H, 3.81; N, 3.59; S, 7.66%. KM (X−1 cm2 mol−1):
Physical measurements
1
3.8. IR (Nujol mull, cm−1): (C5H4SN) 1566 (vs), 1542 (vs). H
NMR (d, in CDCl3): 7.80 (m, 8H, Ph), 7.62 (d, 3JH6–H5 = 4.87 Hz,
1H and 31P NMR spectra were recorded on a Varian Unity
300 MHz or INOVA 400 MHz for 1H, and 121.4 MHz or
3
2H, C5H4SN), 7.32 (m, 12 H, Ph), 7.26 (d, JH3–H4 = 10.96 Hz,
2H, C5H4SN), 6.84 (td, 3JH4–H5 = 7.39 Hz, 4JH4–H6 = 1.93 Hz, 2H,
1
161.9 MHz for 31P, in CDCl3 or CD2Cl2 solutions; H chemical
C5H4SN), 6.40 (t, 3JH–H = 7.58 Hz, 2H, C5H4SN), 2.21 (d, 2JH–P
=
shifts are quoted relative to tetramethylsilane (internal reference)
and the 31P NMR chemical shifts to H3PO4 (external reference)
or to an internal reference. IR spectra were recorded on a Perkin
Elmer 843 (range 4000–200 cm−1) and/or a Nicolet Impact 410
FTIR (range 4000–400 cm−1) spectrophotometers using Nujol
mulls between polyethylene sheets. Conductivity measurements
were performed at 298 K using a Crison 522 conductimeter (c ≈
5.10−4 M). The C, H, N and S analyses were performed with a
LECO CHNS 932 microanalyser. Mass spectra were recorded on
a VG Autospec, by LSIMS+ using nitrobenzyl alcohol as matrix.
The X-ray intensity data were collected with an Enraf Nonius
Kappa CCD detector or a Bruker-Smart CCD diffractometer with
1
18.17 Hz, 3JH–Pt = 47.1 Hz, 4H, –CH2–, dppe). 31P{ H} NMR (d,
in CDCl3): 46.29 (s, 1JP–Pt = 2966.29 Hz). MS-LSIMS+ (m/z): 703
[Pt(C5H4SN)(dppe)+, 100%].
Preparation of [Pd(S-C5H4SN)2(dppe)] (3). NaC5H4SN
(0.610 mmol)—prepared in situ from NaEtO 0.1 M (6.1 mL,
0.610 mmol) and C5H5SN (67.8 mg, 0.610 mmol) in absolute
ethanol (20 mL)—was added to a suspension of [PdCl2(dppe)]
(175.5 mg, 0.305 mmol) in absolute ethanol (20 mL) under
an inert atmosphere. A white-yellow suspension in an orange
solution was formed immediately. After stirring for 24 h at room
temperature, the solvent was removed under vacuum to ca. 5 mL
and the solid filtered off. The resulting gold-yellow solid was
purified by re-crystallisation from dichloromethane–hexane and
3 was isolated in 83% yield. Anal. Calcd for C36H32PdN2P2S2:
C, 59.63; H, 4.45; N, 3.86; S, 8.84. Found: C, 59.42; H, 4.65; N,
3.95; S, 8.97%. KM (X−1 cm2 mol−1): 1.7. IR (Nujol mull, cm−1):
(C5H4SN) 1567 (vs), 1542 (vs). 1H NMR (d, in CDCl3): 7.79
(m, 10H, Ph, –N–C–H–, C5H4SN), 7.36 (m, 12H, Ph), 7.07
˚
graphite-monochromated Mo-Ka (k = 0.71073 A).
Syntheses
Preparation of [Pt(S-C5H4SN)2(dppm)] (1). NaC5H4SN
(0.390 mmol)—prepared in situ from NaEtO 0.1 M (3.9 mL,
0.390 mmol) and C5H5SN (43.4 mg, 0.390 mmol) in absolute
CH3CH2OH (20 mL)—was added to a suspension of [PtCl2-
(dppm)] (127 mg, 0.195 mmol) in absolute CH3CH2OH (20 mL)
under an inert atmosphere. A pale bright yellow solution was
formed immediately and the white solid in suspension remained
mixed with a pale yellow solid. After stirring for 24 h at room
temperature, the solvent was removed partially to concentrate the
suspension to ca. 5 mL. The solid was filtered off and dissolved
in CH2Cl2 (10 mL). The yellow solution was then filtered and
concentrated to ca. 2 mL under vacuum. Diethyl ether was added
to precipitate the product followed by filtration, washing with
diethyl ether and hexane to produce a pale yellow crystalline solid
in 86% yield. X-Ray quality crystals were grown by slow diffusion
of hexane into a CH2Cl2 solution of the complex. Anal. Calcd
for C35H30PtN2P2S2: C, 52.56; H, 3.78; N, 3.51; S, 8.00. Found:
C, 52.40; H, 3.93; N, 3.43; S, 7.84%. KM (X−1 cm2 mol−1): 2.18.
3
3
(d, JH3–H4 = 8.00 Hz, 2H, C5H4SN), 6.79 (t, JH–H = 8.00 Hz,
3
2H, C5H4SN), 6.44 (t, JH–H = 8.00 Hz, 2H, C5H4SN), 2.31
2
1
(d, JH–P = 20.0 Hz, 4H, –CH2–, dppe). 31P{ H} NMR (d, in
CDCl3): 57.7 (s). MS-LSIMS+ (m/z): 614 [Pd(C5H4SN)(dppe)+,
100%].
Preparation of [Pd2(l2-S,N-C5H4SN)(l2-j2S-C5H4SN)(l2-
dppm)(S-C5H4SN)2] (4). NaC5H4SN (0.390 mmol)—prepared
in situ from NaEtO 0.1 M (3.9 mL, 0.390 mmol) and C5H5SN
(43.4 mg, 0.390 mmol) in CH3CH2OH (20 mL)—was added
to a suspension of [PdCl2(dppm)] (127 mg, 0.195 mmol) in
CH3CH2OH (20 mL) under an inert atmosphere. A clear orange
solution appeared within 5 minutes and the resulting solution
was stirred for 4 h. The solution was concentrated under vacuum
to ca. 1 mL, dichloromethane (10 mL) was added and the solid
residue filtered off. Concentration of the resulting solution to ca.
2 mL and addition of hexane (20 mL) led to 4 as an orange solid
in 76% yield. X-Ray quality crystals were grown by slow diffusion
of hexane into a CH2Cl2 solution of the complex. Anal. Calcd for
C45H38Pd2N4P2S4: C, 52.08; H, 3.69; N, 5.39; S, 12.36. Found: C,
51.82; H, 3.65; N, 5.20; S, 12.00%. KM (X−1 cm2 mol−1): 2.8. IR
(Nujol mull, cm−1): (C5H4SN) 1587 (s), 1572 (vs), 1558 (m), 1542
(s). 1H NMR (d, in CDCl3): 9.39 (m, 1H, C5H4SN), 8.66 (m, 1H,
C5H4SN), 8.48 (m, 1H, C5H4SN), 8.44 (m, 1H, C5H4SN), 8.23
(m, 1H, C5H4SN), 7.88 (m, 8H, Ph), 7.70 (m, 2H, C5H4SN), 7.50
1
IR (Nujol mull, cm−1): (C5H4SN) 1573 (vs), 1545 (s). H NMR
3
(d, in CDCl3): 7.84 (m, 8 H, Ph), 7.41 (d, JH6–H5 = 7.15 Hz, 2
H, C5H4SN), 7.27 (m, 12 H, Ph), 7.09 (m, 2H, C5H4SN), 6.96 (t,
3
3JH5–H4 = 6.88 Hz, 2H, C5H4SN), 6.31 (t, JH–H = 6.80 Hz, 2H,
2
1
31
C5H4SN), 4.33 (t, JH–P = 14.7 Hz, 2H, –CH2–, dppm). H{ P}
NMR (d, in CDCl3): 4.33 (s, 3JH–Pt = 58.1 Hz, 2H, –CH2–, dppm).
31P{ H} NMR (d, in CDCl3): −49.8 (s, 1JP–Pt = 2780.1 Hz). MS-
1
LSIMS+ (m/z): 689 [Pt(C5H4SN)(dppm)+, 100%].
Preparation of [Pt(S-C5H4SN)2(dppe)] (2). NaC5H4SN
(0.386 mmol)—prepared in situ from NaEtO 0.1 M (3.9 mL,
610 | Dalton Trans., 2006, 609–616
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©

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(m, 2H, C5H4SN), 7.33 (m, 12H, Ph), 7.05 (m, 1H, C5H4SN),
6.92 (m, 1H, C5H4SN), 6.85 (m, 2H, C5H4SN), 6.53 (m, 1H,
52.80; H, 4.13; N, 3.23; S, 7.64%. KM (X−1 cm2 mol−1): acetone, 3.2.
IR (Nujol mull, cm−1): (C5H4SN) 1572 (vs), 1541 (s). 1H NMR (d,
in CD2Cl2): 7.96 (d, 3JH6–H5 = 5.40 Hz, 2H, C5H4SN), 7.60 (m, 8H,
Ph), 7.26 (m, 12H, Ph), 6.99 (d, 3JH3–H4 = 8.05 Hz, 2H, C5H4SN),
6.87 (td, 3JH–H = 7.0 Hz, 4JH4–H6 = 1.83 Hz, 2H, C5H4SN), 6.63 (t,
2
C5H4SN), 6.04 (m, 2H, C5H4SN), 4.36 (dt, JH–P = 11.6 Hz,
2
1H, –CH2–, dppm), 4.21 (dt, JH–P = 11.6 Hz, 1H, –CH2–,
1
31
dppm). H{ P} NMR (d, in CDCl3): 4.40 (d, AB system, JAB
=
14.6 Hz, 1H, –CH2–, dppm), 4.18 (d, AB system, JAB = 14.6 Hz,
3JH5–H6 = 6.50 Hz, 2H, C5H4SN), 2.06 (t, 2JH–P = 3.50 Hz, 3JH–Pt
=
=
=
1H, –CH2–, dppm). 31P{ H} NMR (d, in CDCl3): 33.75 (d,
24.8 Hz, 6H, –CH3). 1H{ P} NMR (d, in CD2Cl2): 2.06 (s, 3JH–Pt
1
31
2JP–P = 48.6 Hz), 29.15 (d, 2JP–P = 48.6 Hz). MS-FAB (m/z): 600
24.8 Hz, 6H, –CH3). 31P{ H} NMR (d, in CD2Cl2): 8.28 (s, 1JP–Pt
1
[Pd(C5H4SN)(dppm)+, 20%], 928 [Pd2(C5H4SN)3(dppm)+, 60%].
2733.3 Hz). MS-FAB+ (m/z): 505 [Pt(C5H4SN)(PPh2Me)+, 33%],
+
705 [Pt(C5H4SN)(PPh2Me)2 , 100%].
Preparation of [Pd2(l2-S,N-C5H4SN)3(l2-dppm)]Cl (5).
NaC5H4SN (0.463 mmol)—prepared in situ from NaEtO 0.1 M
(4.6 mL, 0.463 mmol) and C5H5SN (51.4 mg, 0.463 mmol) in
absolute CH3CH2OH (20 mL)—was added to a suspension of
[PdCl2(dppm)] (259.9 mg, 0.463 mmol) in absolute CH3CH2OH
(20 mL) under an inert atmosphere. A clear red-orange solution
appeared within 5 minutes and it was stirred for 6 h. The solution
was concentrated under vacuum to ca. 1 mL, dichloromethane
(10 mL) was added and the solid residue filtered off. Concentration
of the resulting solution to ca. 2 mL and addition of hexane
(20 mL) resulted in 5 as a red-orange solid in a 63% yield.
X-Ray quality crystals were grown by slow diffusion of hexane
into a CH2Cl2 solution of the complex giving the corresponding
dichloromethane and water solvate of complex 5. Anal. Calcd for
C41H38Pd2N3OP2S3Cl: C, 46.19; H, 3.59; N, 3.94; S, 9.02. Found:
C, 45.93; H, 3.61; N, 3.76; S, 8.78%. KM (X−1 cm2 mol−1): acetone,
Method 2. NaC5H4SN (40 mg, 0.300 mmol)—prepared in situ
from NaEtO 0.1 M (3.0 mL, 0.300 mmol) and C5H5SN (33.3 mg,
0.300 mmol) in absolute CH3CH2OH (20 mL)—was added to
a suspension of [PtCl2(PPh2Me)2] (100.0 mg, 0.150 mmol) in
absolute CH3CH2OH (20 mL) under an inert atmosphere. A pale
bright yellow solution was formed and it became totally clear in
15 minutes. After stirring for 4 h at room temperature, the solution
was concentrated to ca. 5 mL under vacuum and the pale yellow
solid precipitate was isolated by filtration, washed with absolute
ethanol (3 mL) and obtained in 82% yield. It was characterised
1
by elemental analysis and H and 31P NMR spectroscopies as
compound 6.
X-Ray structure determinations of 1, 4, 5 and 6
Pale yellow (1), orange (4), red-orange (5) and yellow (6) crystals,
suitable for X-ray diffraction, were grown by slow diffusion
of hexane into a CH2Cl2 solution of each product at room
temperature. A crystal of each compound was mounted on a
glass fibre with inert oil and centred in a Enraf Nonius Kappa
CCD area detector in the case of 1, or in a Bruker-Smart CCD
diffractometer (4, 5 and 6) with graphite-monochromated Mo-
1
46.0. IR (Nujol mull, cm−1): (C5H4SN) 1585 (s), 1543 (m). H
3
NMR (d, in CDCl3): 9.41 (d, JH–H = 5.15 Hz, 1H, C5H4SN),
8.70 (d, 3JH–H = 5.15 Hz, 1H, C5H4SN), 8.48 (t, 3JH–H = 7.67 Hz,
3
2H, C5H4SN), 8.20 (d, JH–H = 5.77 Hz, 1H, C5H4SN), 8.11 (m,
3
2H, C5H4SN), 7.65 (m, 8H, Ph), 7.43 (t, JH–H = 8.06 Hz, 2H,
C5H4SN), 7.09 (d, 3JH–H = 7.86 Hz, 1H, C5H4SN), 6.93 (m, 12H,
3
2
Ph), 6.58 (dd, JH–H = 6.96 Hz, 2H, C5H4SN), 4.36 (dt, JH–P
=
˚
Ka (k = 0.7107 A) radiation for data collection. Semi-empirical
2
11.8 Hz, 1H, –CH2–, dppm), 4.21 (dt, JH–P = 11.8 Hz, 1H,
absorption corrections based on symmetry-equivalent reflections
–CH2–, dppm). 1H{ P} NMR (d, in CDCl3): 4.34 (d, AB system,
31
using SORTAV27 were applied for 1. For structures 4, 5 and 6, the
JAB = 11.7 Hz, 1H, –CH2–, dppm), 4.21 (d, AB system, JAB
=
SADABS program was used to correct the absorption data.28
A
11.7 Hz, 1H, –CH2–, dppm). 31P{ H} NMR (d, in CDCl3): 32.85
1
summary of the fundamental crystal and refinement data of the
compounds is given in Table 1.
2
2
(d, JP–P = 60.8 Hz), 28.82 (d, JP–P = 60.8 Hz). MS-LSIMS+
(m/z): 490 [Pd(dppm)+, 8%], 600 [Pd(C5H4SN)(dppm)+, 40%],
708 [Pd2(C5H4SN)(dppm)+, 4%], 818 [Pd2(C5H4SN)2(dppm)+,
8%], 928 [Pd2(C5H4SN)3(dppm)+, 21%].
The structures were solved by direct methods using SHELXS.29
Full-matrix least squares refinement was carried out using
SHELXL minimizing w(F0 − Fc )2.30 Weighted R factors (Rw)
and all goodness-of-fit S values are based on F2; conventional R
factors (R) are based on F. In the case of 5 the dichloromethane
molecule is disordered.
2
2
Preparation of trans-[Pt(S-C5H4SN)2(PPh2Me)2] (6).
Method 1. Starting from NaC5H4SN (0.331 mmol)—prepared
in situ from NaEtO 0.1 M (3.3 mL, 0.331 mmol) and C5H5SN
(36.8 mg, 0.331 mmol) in absolute CH3CH2OH (20 mL)—and
[PtCl2(dppm)] (215.3 mg, 0.331 mmol) in absolute CH3CH2OH
(20 mL) the reaction was carried out under the same conditions
mentioned above for all cases. A pale bright yellow solution was
formed immediately and the white suspended solid disappeared
in half an hour. After stirring for 2 h at room temperature,
the solvent was partially removed to concentrate the solution
to ca. 5 mL. The pale yellow suspended solid was filtered off
and dissolved in CH2Cl2 (10 mL). The pale yellow solution was
then filtered and concentrated to ca. 2 mL under vacuum. Hexane
(10 mL) was added to precipitate the product followed by filtration,
washing with hexane to obtain a pale yellow crystalline solid in
40% yield. X-Ray quality crystals were grown by slow diffusion
of hexane into a CH2Cl2 solution of the complex. Anal. Calcd
for C36H34PtN2P2S2: C, 53.00; H, 4.20; N, 3.43; S, 7.86. Found: C,
CCDC reference numbers 275126–275129.
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b508438e
Results and discussion
The reaction of [PtCl2(dppm)], [PtCl2(dppe)] or [PdCl2(dppe)]
with an ethanolic solution of Na(C5H4SN) prepared in situ from
equimolar amounts of C5H5SN and NaOEt in ethanol in a 1 :
2 molar ratio afforded complexes 1, 2 or 3, respectively, in good
yields.
M = Pt L–L = dppm (1); dppe (2)
M = Pd L–L = dppe (3)
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Table 1 Crystallographic data for 1, 4, 5 and 6
1
4
5
6
Empirical formula
M
C35H30N2P2PtS2
799.76
C45H38N4P2Pd2S4
1037.77
C41H38Cl3N3OP2Pd2S3
1066.01
C36H34N2P2PtS2
815.80
Crystal system
Space group
Z
Orthorhombic
P212121
Monoclinic
P21/c
Monoclinic
C2/c
Monoclinic
P21/n
4
4
8
2
˚
a/A
8.577(2)
15.228(3)
23.913(5)
90.00
90.00
90.00
20.508(4)
9.0092(18)
25.545(5)
90.00
112.66(3)
90.00
17.593(4)
16.091(3)
32.380(7)
90.00
93.58(3)
90.00
8.8507(18)
12.027(2)
15.874(3)
90.00
102.75(3)
90.00
˚
b/A
˚
c/A
a/◦
b/◦
c /◦
3
˚
V/A
3123.3(12)
1.701
4355.6(15)
1.583
9149(3)
1.548
1648.1(6)
1.644
qcalcd/g cm−3
Crystal dimensions/mm
T/K
0.3 × 0.25 × 0.25
0.55 × 0.40 × 0.30
0.40 × 0.25 × 0.35
0.15 × 0.10 × 0.10
150(2)
293(2)
293(2)
293(2)
No. of obsd data (I > 2r(I))
R(int)
7142
0.0616
379
47.57
0.0277, 0.0632
0.0308, 0.0647
10779
0.0691
516
11.28
0.0443, 0.0806
0.0966, 0.0949
4272
0.0463
502
12.000
0.0515, 0.1532
0.0633, 0.1607
4084
0.0470
197
44.63
0.0264, 0.0447
0.0538, 0.0494
No. of parameters varied
l/cm−1
R1 (Fo)a, wR2(Fo2)b (I > 2r(I))
R1(Fo), wR2(Fo2) (all data)
1/2
a R1 = R|Fo| − |Fc|/R|Fo|. b wR2 = {Rw[|Fo|2 − |Fc|2]2/Rw(Fo2)2}
.
[MCl2(L–L)] + 2 NaC5H4SN → [M(S–C5H4SN)2(L–L)]
+ 2 NaCl
(1)
The reaction pathway used by us can be considered as a
slight modification of the one previously described21 to prepare
compounds [Pt(S-C5H4SN)2(dppe)] (2) or [Pd(S-C5H4SN)2(dppe)]
(3) starting from PtCl4 or PdCl2 and diphosphine ligand with
C5H5SN and Et3N as deprotonating agent. The spectroscopic
data for 2 and 3 agree with those previously described21 for the
mononuclear complexes although, in the case of complex 2, addi-
tional spectroscopic data are available in the Experimental section.
Complex [Pt(S-C5H4SN)2(dppm)] 1 shows a single resonance at
1
d = −49.8 ppm in the 31P{ H} NMR spectrum in CDCl3 which
agree with a chelating behaviour of the diphosphine ligand.31 The
presence of only a pair of platinum satellites, 1JP–Pt = 2780.1 Hz,
point to a mononuclear structure of 1 similarly to those reported
for complexes 2 and 3.
Fig. 1 Molecular structure of complex 1. Thermal ellipsoids are drawn
at the 50% probability level and H atoms have been omitted for clarity.
Crystals of 1 suitable for X-ray diffraction were grown by slow
diffusion of hexane into a CH2Cl2 solution of the complex. An
ORTEP representation of 1 is shown in Fig. 1 and selected bond
distances and angles for the structure are given in Table 2. The
molecular structure of 1 shows two pyridine-2-thionate ligands
in a syn configuration with a dihedral angle of about 45◦ with
the PtS2P2 plane. The geometry around the platinum atom can
be considered distorted square-planar. The main distortion arises
from the closing of the P(2)–Pt–P(1) and S(2)–Pt-S(1) angles
[74.01(4)◦ and 78.56(4)◦ respectively], and the opening of the
S(2)–Pt-P(2) and S(1)–Pt-P(1) angles [105.19(4)◦ and 102.25(4)◦
respectively] most likely imposed by the small bite angle of the
bis(diphenylphosphino)methane ligand. The phenyl groups in the
dppm ligand are in an up/down configuration on either side
of the PtS2P2 plane, which precludes the presence of short Pt–
Pt intramolecular interactions in the crystal lattice. Referenced
structures of [Pt(S-C5H4SN)2(dppx)] (dppx = dppe, dppn, dppp)21
and [Pt(S-C5H4SN)2(bpy)]32 exhibit a difference in the orientation
of the pyridine-2-thionate ligands. Pt–P distances of 2.2725(11)
◦
˚
Table 2 Bond lengths [A] and angles [ ] for [Pt(S-C5H4SN)2(dppm)] (1)
Pt(1)–P(1)
Pt(1)–P(2)
Pt(1)–S(1)
Pt(1)–S(2)
2.2702(11)
2.2725(11)
2.3358(11)
2.3381(11)
N(1)–C(2)
S(2)–C(2)
S(1)–C(7)
N(2)–C(7)
1.336(5)
1.761(4)
1.748(4)
1.333(5)
P(1)–Pt(1)–P(2)
P(1)–Pt(1)–S(1)
P(2)–Pt(1)–S(1)
P(1)–Pt(1)–S(2)
P(2)–Pt(1)–S(2)
S(1)–Pt(1)–S(2)
C(51)–P(1)–Pt(1)
C(41)–P(1)–Pt(1)
74.01(4)
102.25(4)
174.66(4)
179.16(4)
105.19(4)
78.56(4)
C(1)–P(1)–Pt(1)
C(21)–P(2)–Pt(1)
C(31)–P(2)–Pt(1)
C(1)–P(2)–Pt(1)
C(7)–S(1)–Pt(1)
C(2)–S(2)–Pt(1)
S(2)–C(2)–N(1)
S(1)–C(7)–N(2)
94.27(12)
116.97(14)
124.31(14)
94.40(13)
112.72(14)
114.89(14)
120.7(3)
˚
and 2.2702(11) A are in the range of other mononuclear platinum
derivatives with dppm as chelating ligand: [Pt(L)2(dppm)] (L =
115.73(14)
121.80(13)
CH2Cl,33 SePh,34 SPh35). The Pt–S bond distances are 2.3358(11)
120.8(3)
˚
and 2.3381(11) A, which are in the range of other Pt derivatives
612 | Dalton Trans., 2006, 609–616
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◦
with terminal pyridine-2-thiolate ligands.20,21,32 These P–Pt and
Pt–S bond distances are similar to those found in compound 2;
˚
Table 3 Bond lengths [A] and angles [ ] for [Pd2(l2-S,N-C5H4SN)(l2-
j2S-C5H4SN)(l2-dppm)(S-C5H4SN)2] (4)
21
˚
˚
2.270(3), 2.256(3) A and 2.327(3), 2.389(3) A respectively. The
N–C–S angles of 120.7(3) and 120.8(3) in complex 1 are certainly
close to the ideal angle for sp2 carbons (trigonal angles) and are
characteristic of a (S-C5H4SN) monodentate moiety.20,36 These
angles are 119.8(8)◦ and 114.7(9)◦ in compound 2 and 120.4(6)◦
and 114.7(6)◦ in compound 3.
Pd(1)–P(2)
Pd(1)–S(2)
Pd(1)–S(3)
Pd(1)–S(4)
Pd(1)–Pd(2)
Pd(2)–N(3)
Pd(2)–P(1)
Pd(2)–S(1)
2.2837(11)
2.3262(12)
2.3515(11)
2.3548(11)
2.9584(9)
2.098(3)
Pd(2)–S(4)
S(1)–C(2)
N(1)–C(2)
S(2)–C(7)
S(3)–C(12)
N(3)–C(12)
S(4)–C(17)
N(4)–C(17)
2.3453(10)
1.754(4)
1.343(5)
1.741(5)
1.742(4)
1.352(5)
1.790(4)
1.325(5)
2.2573(11)
2.3361(11)
On the contrary, the reaction of [PdCl2(dppm)] with thionate
salts under similar conditions to those reported above shows
a totally different result. Therefore, the final compound of this
reaction (Scheme 1, i)) has a stoichiometry [Pd2(C5H4SN)4(dppm)]
(4) deduced from elemental analyses, mass spectra (LSIMS+) and
the integration of resonances in the 1H NMR spectrum.
P(2)–Pd(1)–S(2)
P(2)–Pd(1)–S(3)
S(2)–Pd(1)–S(3)
P(2)–Pd(1)–S(4)
S(2)–Pd(1)–S(4)
S(3)–Pd(1)–S(4)
P(2)–Pd(1)–Pd(2)
S(2)–Pd(1)–Pd(2)
S(3)–Pd(1)–Pd(2)
S(4)–Pd(1)–Pd(2)
N(3)–Pd(2)–P(1)
N(3)–Pd(2)–S(1)
P(1)–Pd(2)–S(1)
N(3)–Pd(2)–S(4)
P(1)–Pd(2)–S(4)
S(1)–Pd(2)–S(4)
N(3)–Pd(2)–Pd(1)
P(1)–Pd(2)–Pd(1)
S(1)–Pd(2)–Pd(1)
98.94(5)
177.32(4)
82.25(5)
82.39(4)
178.08(4)
96.36(4)
98.66(3)
127.43(4)
78.74(3)
50.85(3)
172.63(9)
92.05(9)
86.84(4)
90.78(9)
91.13(4)
173.16(4)
93.34(9)
82.35(4)
134.81(3)
S(4)–Pd(2)–Pd(1)
C(28)–P(1)–Pd(2)
C(22)–P(1)–Pd(2)
C(1)–P(1)–Pd(2)
C(34)–P(2)–Pd(1)
C(40)–P(2)–Pd(1)
C(1)–P(2)–Pd(1)
C(2)–S(1)–Pd(2)
C(7)–S(2)–Pd(1)
C(17)–S(4)–Pd(2)
C(17)–S(4)–Pd(1)
Pd(2)–S(4)–Pd(1)
C(12)–S(3)–Pd(1)
C(16)–N(3)–Pd(2)
C(12)–N(3)–Pd(2)
N(1)–C(2)–S(1)
N(2)–C(7)–S(2)
N(3)–C(12)–S(3)
N(4)–C(17)–S(4)
51.14(3)
112.77(13)
116.33(12)
114.38(12)
123.73(13)
114.01(12)
106.32(12)
103.51(14)
105.79(17)
112.03(12)
107.23(13)
78.02(4)
115.28(14)
120.0(3)
120.2(3)
115.0(3)
119.2(3)
123.7(3)
116.1(3)
Scheme 1
Mass spectroscopy shows a signal assignable to the fragment
[Pd2(C5H4SN)3(dppm)]+, m/z 928, 60% in accordance with the
1
proposed stoichiometry by loss of one C5H4SN unit. The 31P{ H}
NMR spectrum shows two doublets at 33.75 and 29.15 ppm,
2JP–P = 48.6 Hz, indicative of non-chelating dppm co-ordination
and the non-equivalence of the two P ends. The 1H NMR shows a
complicated pattern in the phenyl region indicative of different
modes of co-ordination of the thionate ligands and also an
illustrative methylene resonance. The CH2 protons appear as two
doublets of triplets with some modifications of the intensities.
Fig. 2 Molecular structure of complex 4. Thermal ellipsoids are drawn
at the 50% probability level and H atoms have been omitted for clarity.
31
1H{ P} NMR spectroscopy simplified these signals into an AB
system, dA = 4.36, dB = 4.21, JAB = 14.6 Hz which allows the
measurement of JH–P = 11.6 Hz in the original spectrum.
compound has no precedent in the literature. The two pyridine-
2-thionate groups in terminal position are trans to the S bridging
atom, angles S(1)–Pd(2)–S(4) and S(2)–Pd(1)–S(4) being 173.16
(4)◦ and 178.08(4)◦ respectively. Both groups lie almost perpen-
dicular to the Pd2P2NS plane, presumably in order to minimise
repulsions between these rings and the phenyl rings of the dppm
Fortunately crystals suitable for X-ray diffraction studies were
grown. The structure of 4 (Fig. 2) displays a binuclear palladium
A-frame derivative, where both metallic centres show a slightly
distorted square-planar geometry. Selected bond distances and
angles are given in Table 3. The molecule contains four pyridine-2-
thionate ligands in 3 different co-ordination modes: two of them in
a terminal S-monodentate arrangement, the other two as bridging
ligands in two different modes. A l2-S,N and other l2-j2S. This
bridging combination has only been observed previously in the
˚
ligand. The Pd–Pd distance of 2.9584(9) A is intermediate between
38
˚
that found for dimers such as [Pd2Br2(dppm)2] 2.603 A and
[Pd2(C5H4SN)4]·2CHCl3 2.677(1) A,39 with a direct Pd–Pd bond in
˚
the former, and the distances in the A-frame lacking a direct Pd–Pd
40,41
˚
bond (range 3.01–3.3 A).
The presence of three co-ordination
[{Rh(l-C5H4SN)(tfbb)}2] (tfbb
=
tetrafluorobenzobarrelene)
modes allows us to underscore the different angles in monodentate
dimer species37 and three differing co-ordination modes in one
S-pyridin-2-thionate N(1)–C(2)–S(1) 115.0(3)◦, N(2)–C(7)–S(2)
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119.2(3)◦, l2-j2S-bridging N(4)–C(17)–S(4) 116.1(3)◦ or l2-S,N-
bridging N(3)–C(12)–S(3) 123.7(3)◦ compared with 120.6(1)◦ in
pyridine-2-thione.3 Regarding the S–C distances they range from
˚
Table 4 Bond lengths [A] and angles [ ] for [Pd2(l2-S,N-C5H4SN)3(l2-
dppm)]Cl·CH2Cl2·H2O (5)
Pd(1)–N(1)
Pd(1)–N(3)
Pd(1)–P(1)
Pd(1)–S(2)
Pd(1)–Pd(2)
Pd(2)–N(2)
2.081(8)
2.128(7)
2.266(3)
2.296(2)
2.7288(12)
2.089(7)
Pd(2)–P(2)
Pd(2)–S(1)
Pd(2)–S(3)
S(1)–C(2)
S(2)–C(7)
S(3)–C(12)
2.289(3)
2.305(3)
2.355(3)
1.780(12)
1.762(9)
1.768(11)
˚
1.742(4) to 1.790(4) A. The shorter corresponds to l2-S,N co-
ordination and the larger to the l2-j2S co-ordination mode. This
behaviour could be due to a larger electronic demand from the
˚
sulfur atom in the latter. The Pd(2)–N(3) distance of 2.098(3) A
is in the range of other similar compounds where the pyridine-2-
thionate acts as chelating ligand.22,39 However, the Pd–S and Pd–P
bond lengths are slightly longer than those found in the above
mentioned dimers and dppm A-frame derivatives.
N(1)–Pd(1)–N(3)
N(1)–Pd(1)–P(1)
N(3)–Pd(1)–P(1)
N(1)–Pd(1)–S(2)
N(3)–Pd(1)–S(2)
P(1)–Pd(1)–S(2)
N(1)–Pd(1)–Pd(2)
N(3)–Pd(1)–Pd(2)
P(1)–Pd(1)–Pd(2)
S(2)–Pd(1)–Pd(2)
N(2)–Pd(2)–P(2)
N(2)–Pd(2)–S(1)
P(2)–Pd(2)–S(1)
N(2)–Pd(2)–S(3)
P(2)–Pd(2)–S(3)
S(1)–Pd(2)–S(3)
N(2)–Pd(2)–Pd(1)
P(2)–Pd(2)–Pd(1)
S(1)–Pd(2)–Pd(1)
92.3(3)
94.0(2)
173.2(2)
175.1(3)
88.6(2)
85.33(9)
90.5(2)
87.8(2)
94.82(7)
84.81(7)
94.4(2)
175.9(2)
86.52(10)
89.5(2)
176.10(9)
89.61(10)
90.3(2)
93.83(7)
85.56(7)
S(3)–Pd(2)–Pd(1)
C(2)–S(1)–Pd(2)
C(7)–S(2)–Pd(1)
C(12)–S(3)–Pd(2)
C(21)–P(1)–Pd(1)
C(31)–P(1)–Pd(1)
C(1)–P(1)–Pd(1)
C(41)–P(2)–Pd(2)
C(51)–P(2)–Pd(2)
C(1)–P(2)–Pd(2)
C(2)–N(1)–Pd(1)
C(6)–N(1)–Pd(1)
C(7)–N(2)–Pd(2)
C(11)–N(2)–Pd(2)
C(16)–N(3)–Pd(1)
C(12)–N(3)–Pd(1)
N(1)–C(2)–S(1)
N(2)–C(7)–S(2)
N(3)–C(12)–S(3)
86.34(7)
107.4(4)
105.5(3)
104.0(3)
113.4(3)
114.1(4)
114.1(3)
114.5(4)
115.8(3)
111.2(3)
122.8(7)
118.7(7)
120.8(6)
119.9(6)
116.0(7)
124.5(6)
122.0(8)
123.4(6)
121.5(7)
When the reaction is conducted in a 1 : 1 molar ratio
(Scheme 1, ii) a different complex 5 can be obtained as the
main component of the reaction, which can be re-crystallised
from dichloromethane/hexane. The stoichiometry of complex 5
[Pd2(C5H4SN)3 (dppm)]Cl is similar to complex 4 with the replace-
ment of one thionate group by a chlorine atom as evidenced by ele-
mental analyses and the mass spectrum which shows fragments at
[Pd2(C5H4SN)3(dppm)]+, m/z 928, 21%, [Pd2(C5H4SN)2(dppm)]+,
m/z 818, 8% and [Pd2(C5H4SN)(dppm)]+, m/z 708, 4% in accor-
dance with the proposed stoichiometry by successive loss of Cl
and C5H4SN units.
1
The 31P{ H} NMR spectrum shows two doublets at 32.85 and
2
28.82 ppm, JP–P = 60.8 Hz, characteristic of a non-symmetric
bidentate bridging dppm ligand. Also, the 1H NMR is very similar
to the previous complex 4 except in the less complicated phenyl
region and the intensity of the signals. The integration gives a
dppm/thionate ratio of 1 : 3. The methylene region shows a
31
doublet of doublets of triplets resolved into an AB system [1H{ P}
NMR, dA = 4.36, dB = 4.21, JAB = 11.7 Hz] which allowed
2
us to measure JH–P = 11.8 Hz. This spectrum, which does not
change substantially down to the lowest temperature (−55 ◦C)
accessible in CDCl3, points to a structure for complex 5 similar
to those reported for complex 4. Only the conductivity in acetone
(46 X−1 cm2 mol−1), which is intermediate between non-conducting
and 1 : 1 electrolyte, does not agree with this proposition. This is the
reason why the X-ray structure of this complex was undertaken.
An ORTEP representation of the cationic species of 5 is
shown in Fig. 3 and selected bond distances and angles for the
structure are given in Table 4. The crystalline structure of the
dichloromethane and water solvate of complex 5 consists of a
chlorine salt where the cation is a dinuclear lantern-type palladium
derivative with three pyridine-2-thionate ligands and one dppm
acting as bridging ligands. Both palladium centres display a
slightly distorted square-planar geometry. The two pyridine-2-
thionate ligands in the equatorial position are sloping towards
the third pyridine thionate (the one trans to the dppm ligand).
Fig. 3 The structure of the cation of complex 5. Thermal ellipsoids are
drawn at the 50% probability level and H atoms have been omitted for
clarity.
˚
The Pd–Pd distance (2.7288(12) A) is comparable to that in
39
42
˚
˚
[Pd2(l-C5H5NS)4] (2.677(1) A) and [Pd2(l-bttz)4] (2.745(1) A)
(bttz = 1,3-benzothiazole-2-thiolate), but significantly longer than
are 122.0(8)◦, 123.4(6)◦ and 121.5(7)◦, which are wider than in the
other co-ordination modes of pyridine-2-thionate reported in this
work. The N(2)–C(7)–S(2) angle of 123.4(6)◦ is close to the l2-S,N
ligand in 4, 123.7(3)◦, although does not correspond to the l2-S,N
pyridine-2-thionate ligand trans to dppm.
This different behaviour of [PdCl2(dppm)] using a 1 : 1 or
1 : 2 NaC5H4SN molar ratio prompted us to test the reaction
of [PtCl2(dppm)] and [MCl2(dppe)] (M = Pd, Pt) with a 1 : 1
molar ratio of NaC5H4SN. When [MCl2(dppe)] (M = Pd, Pt) is
used under these conditions only complexes 2 and 3 are obtained
43,44
˚
those in [Pd2(mhp)4] (2.546(1)–2.559(3) A)
(mhp = 6-methyl-
˚
2-hydroxypyridinate), [Pd2(chp)4] (2.567(2) A) (chp = 6-chloro-
2-hydroxypyridinate)44 and [Pd2(l-dpb)4] (2.576(1) A) (dpb =
45
˚
N,Nꢀ-diphenylbenzamidine) and slightly shorter than in palladium
metal.46 Again in this complex a short Pd–Pd distance is indicative
of some metal–metal interaction and is probably imposed in this
complex by the presence of the four bridging ligands. The Pd–S,
Pd–N and Pd–P bond lengths are similar to those found in complex
4. The N–C–S angles of the l2-S,N pyridine-2-thionate ligands
614 | Dalton Trans., 2006, 609–616
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with some unreacted starting materials. However, the reaction of
[PtCl2(dppm)] with NaC5H4SN in a 1 : 1 molar ratio affords a
small quantity of an insoluble derivative in ethanol, 6, which
elemental analyses, mass spectra and NMR data surprisingly
identify as [Pt(C5H4SN)2(PPh2Me)2]. Complex 6 was obtained
in 40% yield based on platinum. In the mother liquor of the
reaction [Pt(C5H4SN)2(dppm)] 1 can be identified as an important
component among other phosphine containing materials, which
in ours hands can not be separated.
1
Complex 6 shows a singlet at 8.28 ppm in the 31P{ H} NMR in
CD2Cl2 with only one set of platinum satellites, 1JP–Pt = 2733.3 Hz,
1
which does not seem to belong to a dppm ligand. The H NMR
agrees with the presence of a thionate ligand and, what is even more
remarkable, is the presence of a pseudo-triplet signal at 2.06 ppm,
2
with small JH–P = 3.5 Hz, that changes to a singlet with two
1
31
satellites when the H{ P} NMR spectrum was registered. The
triplet at 2.06 ppm should correspond to the methyl groups of the
two PPh2Me ligands in trans positions, by virtual coupling. The
LSIMS+ mass spectrum points in a similar direction showing
fragments at m/z (%) 505 (33) and 705 (100) assignable to
[Pt(C5H4SN)(PPh2Me)]+, and [Pt(C5H4SN)(PPh2Me)2]+, respec-
tively
Fig. 4 Molecular structure of complex 6. Thermal ellipsoids are drawn
at the 50% probability level and H atoms have been omitted for clarity.
The X-ray structure of one crystal of this compound
has been resolved. An ORTEP representation of trans-[Pt(S-
C5H4SN)2(PPh2Me)2] (6) is shown in Fig. 4 and selected bond
distances and angles for the structure are given in Table 5.
The molecule consists of a centrosymmetric monomer with two
methyl diphenyl phosphine molecules and two pyridine-2-thionate
ligands, mutually trans. The metallic centre shows a slightly
distorted square planar geometry. This structure is analogous
to the previously reported trans-[Pt(C5H4NS)2(PPh3)2]20 although
ligand comes from a cleavage of the dppm ligand. There are
a few references in the literature to P–C bond cleavage in
platinum complexes containing bis(diphenylphosphino)methane.
In some cases, the cleavage occurs under basic phase transference
catalyst (PTC) conditions in which a dppm ligand is hydrolysed
to produce PPh2Me and other fragments,49 and the formation
of trans-[Pt2(l2-OH)2(POPh2)2(PPh2Me)2] from [PtCl2(dppm)] are
also referenced.50 Other photochemical or thermal transformation
of the dppm chelate ring have been reported.51,52 We are currently
doing some research work on this complex to understand the
mechanism of this transformation, the first step of which could be
the replacement of one chlorine atom with the pyridin-2-thionate
ligand. Attempts to increase the yield of 6 by adding one free dppm
to the reaction mixture failed giving similar results. Although in
this case we were not able to isolate the other components of the
reaction, essential to propose a mechanism; we are working with
other heterocyclic thionate ligands to contribute more data to this
reaction process.
˚
with an elongation in the Pt–P bond lengths, being 2.3149(11) A
˚
in 6 and 2.295 and 2.253 A in the reported derivative. In contrast,
they are shorter than in the trans-[PdCl2(PPh2Me)2]47 distances
˚
Pd–P 2.3306 A. It is not possible to compare 6 with the trans-
dichlorobis(methyldiphenylphosphine)platinum(II) because only
the cis isomer is referenced in the literature.48 The Pt–S distances
are in the range of platinum pyridin-2-thionate complexes.20,21,32
Complex trans-[Pt(S-C5H4SN)2(PPh2Me)2] (6) can be obtained
in higher yield (82%) by addition of NaC5H4SN in a 2 : 1
molar ratio, under an inert atmosphere, to a suspension of
[PtCl2(PPh2Me)2] in absolute ethanol. The complex obtained this
way shows identical spectroscopic properties to those of the
one described above, showing that the presence of the PPh2Me
Conclusions
In conclusion we have shown how the reactions of pyridine-2-
thionate with [MCl2(dppm)] (M = Pd or Pt) depend greatly on
the ratio of thionate ligand used. In fact, with palladium we have
shown here two rare examples of dinuclear complexes with three
[Pd2(l2-S,N-C5H4SN)3(l2-dppm)]Cl (5) and four [Pd2(l2-S,N-
C5H4SN)(l2-j2S-C5H4SN)(l2-dppm)(S-C5H4SN)2] (4) thionate
ligands in the molecule and, in the case of 4, the unprecedented
existence of three different modes of co-ordination in the same
molecule, that is: monodentate S-, l2-S,N and l2-j2S. The
comparison of the two structures with three and two thionate
bridging ligands, respectively, shows how the Pd–Pd distance is
◦
˚
Table 5 Bond lengths [A] and angles [ ] for trans-[Pt(S-C5H4SN)2-
(PPh2Me)2] (6)
Pt(1)–P(1)A
Pt(1)–P(1)
Pt(1)–S(1)A
2.3149(11)
2.3149(11)
2.3435(9)
Pt(1)–S(1)
N(1)–C(1)
S(1)–C(1)
2.3435(9)
1.330(4)
1.752(4)
P(1)A–Pt(1)–P(1)
P(1)A–Pt(1)–S(1)A
P(1)–Pt(1)–S(1)A
P(1)A–Pt(1)–S(1)
P(1)–Pt(1)–S(1)
180.00(5)
85.12(3)
94.88(3)
94.88(3)
85.12(3)
180.00(6)
C(1)–S(1)–Pt(1)
C(11)–P(1)–Pt(1)
C(6)–P(1)–Pt(1)
C(21)–P(1)–Pt(1)
S(1)–C(1)–N(1)
106.50(12)
111.08(11)
110.72(13)
121.24(11)
120.3(2)
S(1)A–Pt(1)–S(1)
˚
modified from 2.7291(13) to 2.9583(9) A, which should be imposed
Symmetry transformations used to generate equivalent atoms: A −x + 2,
−y, −z + 2.
by the bridging l2-S,N ligands. In contrast, the chemistry of
platinum derivative [PtCl2(dppm)] affords mononuclear materials.
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33 N. W. Alcock, P. G. Pringle, P. Bergamini, S. Sostero and O. Traverso,
J. Chem. Soc., Dalton Trans., 1990, 1553.
Acknowledgements
34 V. K. Jain, S. Kannan, R. J. Butcher and J. P. Jasinski, J. Chem. Soc.,
Dalton Trans., 1993, 1509.
35 G. W. Wei, M. C. Hong, Z. Y. Huang and H. Q. Liu, Jiegou Huaxue,
1992, 11, 334.
36 S. Wang and J. P. Fackler, Jr., Inorg. Chem., 1989, 28, 2615.
37 M. A. Ciriano, F. Viguri, J. J. Pe´rez-Torrente, F. J. Lahoz, L. A. Oro, A.
Tiripicchio and M. Tiripicchio Camellini, J. Chem. Soc., Dalton Trans.,
1989, 25.
Financial support from MCyT-Spain-(BQU2002-04090-CO2-01
and BQU2002-00435) and JCyL-Spain-(BU15/03) is gratefully
acknowledged. We thank Prof. M. B. Hurtshouse for the X-ray
data collection involved in compound 1.
References
38 R. G. Holloway, B. R. Penfold, R. Colton and M. J. McCormick,
J. Chem. Soc., Chem. Commun., 1976, 485.
39 (a) K. Umakoshi, A. Ichimura, I. Kinoshita and S. Ooi, Inorg. Chem.,
1990, 29, 4005; (b) K. Umakoshi, I. Kinoshita and S. Ooi, Inorg. Chim.
Acta, 1987, 127, L41.
1 E. S. Raper, Coord. Chem. Rev., 1985, 61, 115.
2 E. S. Raper, Coord. Chem. Rev., 1994, 129, 91.
3 E. S. Raper, Coord. Chem. Rev., 1996, 153, 199.
4 E. S. Raper, Coord. Chem. Rev., 1997, 165, 475.
5 P. D. Akrivos, Coord. Chem. Rev., 2001, 213, 181.
6 P. J. Blower and J. R. Dilworth, Coord. Chem. Rev., 1987, 76, 121.
7 R. H. Holm, S. Ciurli and J. A. Weigel, Prog. Inorg. Chem., 1990, 38, 1.
8 J. G. Wright, M. J. Natan, F. M. McDonnell, D. M. Ralston and T. V.
O’Halloran, Prog. Inorg. Chem., 1990, 38, 323.
40 (a) R. A. Stockland, G. K. Anderson and N. P. Rath, J. Am. Chem. Soc.,
1999, 121, 7945; (b) M. L. Kullberg and C. P. Kubiak, Organometallics,
1984, 3, 632; (c) A. W. Hanson, A. J. McAlees and A. Taylor, J. Chem.
Soc., Perkin Trans. 1, 1985, 441; (d) M. A. Khan and A. J. McAlees,
Inorg. Chim. Acta, 1985, 104, 109; (e) G. Besenyei, C. L. Lee, J. Gulinski,
S. J. Rettig, B. R. James, D. A. Nelson and M. A. Lilga, Inorg. Chem.,
1987, 26, 3622; (f) J. A. Davies, A. A. Pinkerton, R. Syed and M.
Vilmer, J. Chem. Soc., Chem. Commun., 1988, 47; (g) S. J. Young,
B. Kellenberger, J. H. Reibenspies, S. E. Himmel, M. Manning, O. P.
Anderson and J. K. Stille, J. Am. Chem. Soc., 1988, 110, 5744; (h) F.
Neve, M. Longeri, M. Ghedini and A. Crispini, Inorg. Chim. Acta, 1993,
205, 15; (i) J. A. Davies, K. Kirschbaum and C. Kluwe, Organometallics,
1994, 13, 3664; (j) I. Foch, L. Parkanyi, G. Besenyei, L. I. Simandi
and A. Kalman, J. Chem. Soc., Dalton Trans., 1999, 293; (k) R. A.
Stockland, G. K. Anderson and N. P. Rath, Organometallics, 1997, 16,
5096; (l) C. Kluwe, J. Muller and J. A. Davies, J. Organomet. Chem.,
1996, 526, 385; (m) G. Besenyei, L. Parkanyi, L. I. Simandi and B. R.
James, Inorg. Chem., 1995, 34, 6118.
9 K. C. Dash and H. Schmidbaur, Metal Ions in Biological Systems,
Marcel Decker, New York, 1982, vol. 14, p. 179.
10 B. M. Sutton, Gold Bull. (Geneva), 1986, 19, 15.
11 M. J. Williams, Organic Superconductors (including Fullerenes) Synthe-
sis, Structure, Properties and Theory, Prentice Hall, Englewood Cliffs,
NJ, 1992.
12 P. J. Sadler, Adv. Inorg. Chem. Radiochem., 1991, 36, 1.
13 J. Burgess, Transition Met. Chem., 1993, 18, 439.
14 D. H. Brown and W. E. Smith, Chem. Soc. Rev., 1980, 9, 217.
15 J. Reedijk, Inorg. Chim. Acta, 1992, 200, 873.
16 M. J. Bloemink and J. Reedijk, in Metal Ions in Biological Systems,
Marcel Dekker Inc, New York, 1996, vol. 32, p. 641.
17 J. G. Reynolds, S. C. Sendlinger, A. M. Murray, J. C. Huffman and G.
Christou, Angew. Chem., Int. Ed. Engl., 1992, 31, 1253.
18 M. Sokolow, Y. Sasaki and K. Umakoshi, Inorg. Chem. Commun., 2001,
4, 142.
41 A. L. Balch, C. T. Hunt, C. L. Lee, M. M. Olmstead and J. P. Farr,
J. Am. Chem. Soc., 1981, 103, 3764.
42 M. Kubiak, Acta Crystallogr., Sect. C, 1985, 41, 1288.
43 W. Clegg, C. D. Garner and M. H. Al-Samman, Inorg. Chem., 1982,
21, 1897.
44 D. P. Brancroft, F. A. Cotton, L. R. Falvello and W. Schwotzer, Inorg.
Chem., 1986, 25, 1015.
19 Y. Nakatsu, Y. Nakamura, K. Matsumoto and S. Ooi, Inorg. Chim.
Acta, 1992, 196, 81.
20 T. S. Lobana, R. Verma and A. Castineiras, Polyhedron, 1998, 17, 3753.
21 T. S. Lobana, R. Verma, G. Hundal and A. Castineiras, Polyhedron,
2000, 19, 899.
45 C. L. Yao, L. P. He, J. D. Korp and J. L. Bear, Inorg. Chem., 1988, 27,
4389.
22 J. H. Yamamoto, W. Yoshida and C. M. Jensen, Inorg. Chem., 1991, 30,
1353.
46 N. N. Greenwood and A. Earnshaw, in Chemistry of the Elements,
23 G. P. A. Yap and C. M. Jensen, Inorg. Chem., 1992, 31, 4823.
24 J. L. Serrano, J. Pe´rez, G. Sa´nchez, J. F. Mart´ınez, G. Lo´pez and E.
Molins, Transition Met. Chem., 2002, 27, 105.
25 (a) D. Drew and J. R. Doyle, Inorg. Synth., 1990, 28, 346; (b) G. K.
Anderson and M. Lin, Inorg. Synth., 1990, 28, 60.
26 D. F. Shriver and M. A. Drezdzon, The manipulation of Air-Sensitive
Compounds, Wiley-Interscience, New York, 2nd edn, 1986.
27 G. M. Sheldrick, SHELXTL, University of Go¨ttingen, Go¨ttingen,
Germany, 1997.
Butterworth-Heinemann, London, 2nd edn, 1997.
47 I. Y. Guzma´n-Jime´nez and K. H. Whitmire, Acta Crystallogr., Sect. C:
Cryst. Struct. Commun., 1999, 55, IUC9900028.
48 K. C. Ho, G. M. McLaughlin, M. McPartlin and G. B. Robertson, Acta
Crystallogr., Sect. B, 1982, 38, 421.
49 I. J. B. Lin, H. I. Shen and D. F. Feng, J. Chin. Chem. Soc. (Taipei),
1995, 42, 783 and references therein.
50 P. Bergamini, S. Sostero, O. Traverso, T. J. Kemp and P. G. Pringle,
J. Chem. Soc., Dalton Trans., 1989, 2017.
51 (a) S. Al-Jibori, M. Hall, A. T. Hutton and B. L. Shaw, J. Chem.
Soc., Chem. Commun., 1982, 1069; (b) S. Al-Jibori, M. Hall, A. T.
Hutton and B. L. Shaw, J. Chem. Soc., Dalton Trans., 1984,
863.
52 (a) P. E. Garrou, Chem. Rev., 1985, 85, 171; (b) N. M. Doherty, G.
Hogarth, S. A. R. Knox, K. A. McPherson, F. Melchior and A. G.
Orpen, J. Chem. Soc., Chem. Commun., 1986, 540; (c) G. Hogarth,
S. A. R. Knox and M. L. Turner, J. Chem. Soc., Chem. Commun., 1990,
145.
28 G. M. Sheldrick, SADABS, Empirical Absorption Program, University
of Go¨ttingen: Go¨ttingen, Germany, 1996.
29 G. M. Sheldrick, SHELXS, Program for Crystal Structure Solution,
University of Go¨ttingen, Go¨ttingen, Germany, 1990.
30 G. M. Sheldrick, SHELXL, Program for the refinement of crystal
structures from diffraction data, University of Go¨ttingen, Go¨ttingen,
Germany, 1997.
31 P. E. Garrou, Chem. Rev., 1981, 81, 229.
32 B. C. Tzeng, W. F. Fu, C. M. Che, H. Y. Chao, K. K. Cheung and S. M.
Peng, J. Chem. Soc., Dalton Trans., 1999, 1017.
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