New Pt(II) complexes containing hemilabile thioether-pyrazole ligands. Structural analysis by 1H, 13C{1H} and 195Pt{1H} NMR spectroscopy and crystal structure of [PtCl(bdtp)](BPh4) [bdtp = 1,5-bis(3,5-dimethyl-1-pyrazolyl)-3-thiapentane]

Article abstract of DOI:10.1016/j.poly.2006.12.034

Treatment of the ligand 1,5-bis(3,5-dimethyl-1-pyrazolyl)-3-thiapentane (bdtp) with several platinum starting materials, such as K₂PtCl₄, PtCl₂, [PtCl₂(CH₃CN)₂] and [PtCl₂(PhCN)₂], have been developed under different conditions. The reactions did not yield pure products. The ratio of the NSN, NS and NN isomers has been calculated through NMR experiments. Subsequent treatment of the mixtures of complexes with NaBPh₄ gave [PtCl(bdtp)](BPh₄) (1). These Pt(II) complexes were characterised by elemental analysis, conductivity measurements, IR spectroscopy and ¹H, ¹³C{¹H} and ¹⁹⁵Pt{¹H} NMR spectroscopy. A mixture of complexes was again obtained when the complex [PtCl(bdtp)](BPh₄) was heated under reflux in a solution of Et₄NBr in CH₂Cl₂/MeOH (1:1). This proves the hemilability of the ligand bdtp with Pt(II). The X-ray crystal structure of the complex [PtCl(bdtp)](BPh₄) was determined. The crystal structure contains two kinds of discrete [PtCl(bdtp)]⁺ cations, two BPh₄^- anions and two acetonitrile solvent molecules. In both cations the metal atom is tri-coordinated by the two azine nitrogen atoms and one thioether sulfur atom of the thioether-pyrazole ligand, its coordination (distorted square planar) being completed with one chlorine atom.

Full text of DOI:10.1016/j.poly.2006.12.034

Polyhedron 26 (2007) 2498–2506
www.elsevier.com/locate/poly
New Pt(II) complexes containing hemilabile thioether-pyrazole ligands.
1
13
195
Structural analysis by H, C{1H} and Pt{1H} NMR spectroscopy
and crystal structure of [PtCl(bdtp)](BPh4)
[bdtp = 1,5-bis(3,5-dimethyl-1-pyrazolyl)-3-thiapentane]
a
a,
a
b
*
´
´
Antonio de Leon , Josefina Pons , Jordi Garcıa-Anton , Xavier Solans ,
b
a,
*
`
Merce Font-Bardia , Josep Ros
a
` `
Departament de Quı´mica, Unitat de Quı´mica Inorganica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
b
` `
Cristal.lografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Martı i Franques s/n, 08028 Barcelona, Spain
´
Received 5 December 2006; accepted 22 December 2006
Available online 5 January 2007
Abstract
Treatment of the ligand 1,5-bis(3,5-dimethyl-1-pyrazolyl)-3-thiapentane (bdtp) with several platinum starting materials, such as
K2PtCl4, PtCl2, [PtCl2(CH3CN)2] and [PtCl2(PhCN)2], have been developed under different conditions. The reactions did not yield pure
products. The ratio of the NSN, NS and NN isomers has been calculated through NMR experiments. Subsequent treatment of the mix-
tures of complexes with NaBPh4 gave [PtCl(bdtp)](BPh4) (1). These Pt(II) complexes were characterised by elemental analysis, conduc-
tivity measurements, IR spectroscopy and 1H, 13C{1H} and 195Pt{1H} NMR spectroscopy. A mixture of complexes was again obtained
when the complex [PtCl(bdtp)](BPh4) was heated under reflux in a solution of Et4NBr in CH2Cl2/MeOH (1:1). This proves the hemila-
bility of the ligand bdtp with Pt(II). The X-ray crystal structure of the complex [PtCl(bdtp)](BPh4) was determined. The crystal structure
contains two kinds of discrete [PtCl(bdtp)]+ cations, two BPh4 anions and two acetonitrile solvent molecules. In both cations the metal
ꢀ
atom is tri-coordinated by the two azine nitrogen atoms and one thioether sulfur atom of the thioether-pyrazole ligand, its coordination
(distorted square planar) being completed with one chlorine atom.
ꢀ 2007 Elsevier Ltd. All rights reserved.
Keywords: Platinum(II); Hemilabile ligands; N ligands; S ligands; Pyrazole complexes; Crystal structure
1. Introduction
utable to polydentate chelate ligands containing two types
of bonding groups (one labile and one inert). It should be
emphatisised than hemilability is not an intrinsic property
of the sole ligand and it implies the metal–ligand couple [3].
In the last 5 years, our research group has focused their
interest in the chemistry of hemilabile ligands, in particular
we have studied and reported the synthesis and character-
isation of hemilabile ligands based on the pyrazolyl group
and on some other groups containing N [4], P [5], O [6] or S
[7] atoms, and their reactivity with Pd(II), Pt(II) and Rh(I).
This paper continues the study of the potential hemilability
of ligands containing pyrazolyl and thioether groups [7], in
particular with the ligand 1,5-bis(3,5-dimethyl-1-pyra-
zolyl)-3-thiapentane (bdtp) [7c,8]. Previously other authors
Ligands that contain significantly different chemical
functions such as hard and soft donors (often called hybrid
ligands) find increasing use in chemistry because of the
selectivity introduced in the metal–ligand interactions and
their possible dynamic behaviour [1]. New molecular inter-
actions and properties may allow the emergence of useful
concepts that help tailor molecular structures oriented
towards a given property. The term ‘‘hemilabile ligand’’
was introduced in 1979 by Jeffrey and Rauchfuss [2], attrib-
*
Corresponding author. Fax: +34 93 581 31 01.
E-mail address: Josefina.Pons@uab.es (J. Pons).
0277-5387/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2006.12.034

A. de Leon et al. / Polyhedron 26 (2007) 2498–2506
2499
have studied and described in the literature the reactivity of
the ligand bdtp with different metals such as Ni(II), Co(II),
Cu(I), Zn(II), Ag(I), Cd(II) and Re(I) [9], and our research
group recently has reported the reactivity of the ligand
bdtp with Pd(II). We have demonstrated the hemilabile
properties of this ligand when coordinated to Pd(II) [7c].
In this paper, we have studied the reactivity of the ligand
bdtp [7c,8] towards Pt(II), under various conditions and
with several platinum starting materials.
Isomer NS: two signals can be observed for the C–Hpz of
the coordinated ligand in this isomer. One of them appears
at the same position as the free ligand (d(C–Hpz) =
5.76 ppm) and the other one at d(C–Hpz) = 5.82 ppm. Inte-
gration of both peaks is identical.
Isomer NN: this is a third isomer, which was characterised
by comparison to the complex [PdCl2(bdtp)] (d(C–Hpz) =
5.90 ppm) [7c].
Elemental analyses are consistent with the mixtures.
The IR spectra of the complexes with bdtp show bands at
1555–1553 cmꢀ1 (m(C@C), m(C@N))ar, 1465–1418 cmꢀ1
(d(C@C), d(C@N))ar, 1100–1021 cmꢀ1 d(C–H)ip and 801–
800 cmꢀ1 d(C–H)oop, indicating the presence of the unal-
tered coordinated ligand [7c,8]. Coordination to platinum is
demonstrated in the IR spectra between 500 and 100 cmꢀ1
of the mixture of compounds. According to IR data, the
Pt atom is coordinated to nitrogen atoms [m(Pt–N) between
444 and 441 cmꢀ1], sulfur atoms [m(Pt–S) between 419 and
380 cmꢀ1] and chlorine atoms [m(Pt–Cl) between 333 and
326 cmꢀ1] [13].
2. Results and discussion
2.1. Synthesis and spectroscopic properties
Reaction of 1,5-bis(3,5-dimethyl-1-pyrazolyl)-3-thiapen-
tane (bdtp) [7c,8] (Scheme 1) with several platinum starting
materials, such as K2PtCl4, PtCl2, [PtCl2(CH3- CN)2] [10]
and [PtCl2(PhCN)2] [11], have been developed under different
conditions (Scheme 2). In general, and in contrast to the
Pd(II) complexes, these reactions take a longer time and need
higher temperatures to occur. This same behaviour is observed
with the ligands 1,8-bis-(3,5-dimethyl-1-pyrazolyl)-3,6-dith-
iaoctane (bddo), 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithi-
anonane (bddn) and 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,
5-dithiahexane (bddh) [12].
The reaction did not yield pure products. Unfortunately,
isolation of the different isomers by silica gel chromatogra-
phy was unsuccessful. Recrystallisations of the mixture
with different solvents have been carried out but pure prod-
ucts could not be obtained.
The 1H NMR, 13C{1H} NMR, HMQC, COSY and
NOESY spectra were recorded in CDCl3. The NMR exper-
iments corroborate the obtaining of mixtures and the coor-
dination of the ligands around the metallic centre. This
ligand can act as tridentate (NSN) or bidentate (NS or
NN) chelates depending on the Pt(II) starting material.
In order to be able to isolate one of the isomers (NSN)
from the mixture, treatment of the bdtp mixture with
NaBPh4 was carried out. This reaction gave a compound
of the formula [Pt(bdtp)](BPh4) (1) as a pure products
(NSN isomer).
When the complex 1 was heated under reflux in a solu-
tion of Et4NBr in CH2Cl2/MeOH (1:1) for 24 h, mixtures
of complexes were again obtained (NSN (55%) and NN
(45%) isomers with bromides instead of chlorides bonded
to the metallic centre). This proves the type III hemilability
of the ligand bdtp towards Pt(II) [1a]. The elemental anal-
ysis of 1 is consistent with the formula [PtCl(bdtp)](BPh4).
The positive ionisation electrospray mass spectrum of 1
gave a peak with a m/z value of 509 [PtCl(bdtp)]+ (mole-
cular peak of the cation is observed with the same isotope
The resulting products of these reactions have been
characterised by elemental analyses, and infrared and
NMR spectra.
The ratio of NS, NSN and NN products has been calcu-
1
lated through H NMR experiments (integration of C–Hpz
signals, see Section 4) (see Fig. 1).
The different isomers were distinguished using the fol-
lowing criteria:
Isomer NSN: pure NSN complex (d(C–Hpz) =
6.03 ppm) could be obtained when the platinum starting
material is [PtCl2(CH3CN)2].
N
N
N
N
S
S
+
S
N
N
N
N
N
N
N
N
N
N
N
N
S
Pt
Cl
Pt
Pt
Cl Cl
Cl
Cl
NN
NS
NSN
Scheme 1.

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A. de Leon et al. / Polyhedron 26 (2007) 2498–2506
H2O
NS (59%) + NSN (33%) + NN (8%)
bdtp + K2PtCl4
25ºC
CHCl3
Reflux
NS (31%) + NSN (55%) + NN (14%)
NSN (100%)
bdtp + PtCl2
CH3CN
Reflux
bdtp + [PtCl2(CH3CN)2]
bdtp + [PtCl2(PhCN)2]
CHCl3
Reflux
NS (67%) + NSN (26%)+ NN (7%)
The ratio of the species has been calculated through 1H-NMR experiments,
especially from the integration of the pyrazolic proton
Scheme 2.
distribution as the theoretical one). The conductivity mea-
surements in DMF for 1, show that the complex behaves as
1:1 electrolyte in solution [14].
the coordinated ligands. NMR spectroscopy data are
reported in Section 4 (see Fig. 1).
The 1H NMR spectrum of complex 1 shows that the two
protons of each CH2 moiety in the S–CH2–CH2–N chains
are diastereotopic, thus leading to four groups of signals,
which can be associated to a single hydrogen atom in each
chain. This happens because of the rigid conformation of
the ligand when complexed. Thus, each group of signals
can be assigned as doublets of doublets of doublets
(Fig. 2). The HMQC spectrum allowed us to assign the
two doublets of doublets of doublets of lower d to 7-H
and the ones at higher d to 6-H (Fig. 3). Study of the S–
CH2–CH2–N fragment as an AA0XX0 system gave a set
The IR spectrum of complex 1 is similar to that of the
ligand, the most characteristic bands being those attribut-
able to the pyrazolyl group: m(C@C), m(C@N) at 1579,
1576 cmꢀ1 and d(C–H)oop at 799 cmꢀ1. The m(B–C) band
at 736 cmꢀ1 is characteristic for 1 [15]. The m(Pt–N),
m(Pt–S) and m(Pt–Cl) bands can be attributable to the sig-
nals appearing at 442 cmꢀ1, 380 cmꢀ1 and 326 cmꢀ1
respectively [13].
,
1H and 13C{1H} NMR spectra of compound 1 were
recorded in [D6]acetone solution, and show the signals of
Fig. 1. 1H NMR 250 MHz spectrum of the mixture bdtp + [PtCl2(PhCN)2].

A. de Leon et al. / Polyhedron 26 (2007) 2498–2506
2501
H7S
+
H7S
H6R
H6S
H6S
H6R
S
N
N
N
Pt
N
H7R
S
Cl
N
6.000 5.800 5.600 5.400 5.200 5.000 4.800 4.600 4.400 4.200 4.000 3.800 3.600 3.400 3.200 3.000 2.800 2.600
6R-H
7R-H
6S-H
7S-H
Fig. 2. The 250-MHz 1H NMR and the simulated gNMR spectrum for the NCH2CH2S fragment of [PtCl(bdtp)](BPh4) (1) including the numbering and
the dihedral angles for the NCH2CH2S fragment.
of coupling constants (Table 1). These constants were con-
sistent with the simulated spectra obtained with the aid of
the gNMR program [16].
In the NOESY spectrum it can be seen that the methyl
group at d = 2.48 ppm shows a NOE interaction with the
doublet of doublets of doublets at d = 4.87 ppm, but not
with the one at d = 5.19 ppm. From the X-ray structure
of 1, it can be observed that the nearest proton to the
CH3(5) moiety is 6S-H (Figs. 2 and 4) and therefore it
˚
should be the one with the NOE interaction (2.70 A cation
˚
A and 2.73 A cation B). This information leads us to assign
6S-H to the doublet of doublets of doublets at
d = 4.87 ppm and 6R-H to the signal at d = 5.19 ppm.
The coupling constants enabled us to differentiate 7S-H
Fig. 3. The 250-MHz 2D HMQC spectrum of [PtCl(bdtp)](BPh4) (1).

2502
A. de Leon et al. / Polyhedron 26 (2007) 2498–2506
Table 1
1H NMR results: chemical shifts (ppm) and 1H, 1H coupling constants
(Hz) for 1 in [D6]acetone
Compound
1
d 6R-H
d 6S-H
d 7S-H
d 7R-H
5.19
4.87
3.79
3.38
2J(6R-H, 6S-H)
2J(7R-H, 7S-H)
3J(6R-H, 7R-H)
3J(6S-H, 7S-H)
3J(6R-H, 7S-H)
3J(6S-H, 7R-H)
15.24
14.90
12.03
2.85
2.99
2.09
and 7R-H. These coupling constants agree with the confor-
mation of the S–CH2–CH2–N chain as seen in the X-ray
2
crystal structure (Figs. 2 and 4). Geminal J and ca. 180ꢁ,
3J coupling constants have significantly higher values than
ca. 30ꢁ and ca. 60ꢁ 3J coupling constants. Thus, 7R-H
should correspond to the doublet of doublets of doublets
at 3.38 ppm and 7S-H to the one at d = 3.79 ppm [15,17].
Additional 195Pt{1H} NMR experiments for complex 1
at 298 K revealed only one band (d = ꢀ1880 ppm). The
195Pt{1H} chemical shifts are downfield compared to other
complexes with [PtN2SCl] cores (ꢀ4098, ꢀ2312 ppm) [18].
2.2. Crystal structure of [PtCl(bdtp)](BPh4)-CH3CN
The crystal structure of 1 contains two kinds of discretꢀe
[PtCl(bdtp)]+ cations (cations A and B) (Fig. 4), two BPh4
anions and two acetonitrile solvent molecules. Table 2 lists
some selected bond distances and angles.
The cations A and B have the same structure, [PtCl-
(bdtp)]+. In both, the cationic complex is mononuclear,
and the Pt(II) is coordinated to the bdtp ligand by its three
donor atoms (two nitrogen atoms of the pyrazolyl group
and one sulfur atom), along with one chlorine atom, in a
slightly distorted square-planar geometry. Tetrahedral dis-
tortion can be observed from the bond angles and from the
˚
largest deviation to the mean plane (0.039(4) A cation A
˚
and 0.072(4) A cation B) of the atoms coordinated to the
Pt atom in relation to the mean plane that contains these
four atoms and the Pt atom (cation A: N(1), N(4), S(1),
Cl(1); cation B: N(8), N(5), S(2), Cl(2)). The dihedral angle
between the planes N(1)–Pt(1)–Cl(1) and N(4)–Pt(1)–S(1);
and N(5)–Pt(2)–Cl(2) and N(8)–Pt(2)–S(2) are 4.10(2)ꢁ
and 5.88(2)ꢁ, respectively. The bdtp ligand acts as a triden-
tate chelate and forms two six-membered rings, with a boat
form for Pt(1)S(1)C(8)C(9)N(3)N(4) and Pt(1)S(1)C(7)C(6)
N(2)N(1) (cation A) and with a twist-boat form for
Pt(2)S(2)C(22)C(23)N(7)N(8) and a boat conformation
for Pt(2)S(2)C(21)C(20)N(6)N(5) (cation B).
The [PtN2SCl] core is present in 45 complexes in the lit-
erature. Only in 13 of them is the S a thioether [19]. The Pt–
˚
Fig. 4. ORTEP drawing of [PtCl(bdtp)]+ (a: cation A, b: cation B)
showing all non-hydrogen atoms and the atom numbering scheme; 50%
probability amplitude displacement ellipsoids are shown.
Npz bond lengths [2.025(4) and 1.999(5) A (cation A);
˚
2.008(4) and 2.014(4) A (cation B)], the Pt–S bond lengths
[2.2616(12) A (cation A); 2.2559(12) A (cation B)] and the
˚
˚

A. de Leon et al. / Polyhedron 26 (2007) 2498–2506
2503
Table 2
`
Service of the Universitat Autonoma de Barcelona on a
Carlo Erba CHNS EA-1108 instrument. Conductivity mea-
surements were performed at room temperature (r.t.) in
10ꢀ3 M DMF solutions, employing a CyberScan CON 500
(Euthech instrument) conductimeter. Infrared spectra were
run on a Perkin–Elmer FT spectrophotometer, series
2000 cmꢀ1 as KBr pellets or polyethylene films in the range
4000–100 cmꢀ1. 1H NMR, 13C {1H} NMR, HMQC, COSY,
NOESY spectra were recorded on a NMR-FT Bruker
AC-250 MHz spectrometer in CDCl3, and [D6]acetone solu-
tions at room temperature. 195Pt{1H} NMR spectra were
recorded at 25 ꢁC and 77.42 MHz on a DPX-360 Bruker
spectrometer using aqueous solutions of [PtCl6]2ꢀ (0 ppm)
as an external reference and delay time 0.01 s. All chemical
shifts values (d) are given in ppm. Positive ion ESI-MS mass
spectrometer experiments were performed by the Scientific
technique Services of the Universitat de Barcelona on a
ZQ (Micromass Instruments, UK). The electrospray inter-
face (pneumatically assisted) was operated under the follow-
ing conditions: the nebulizing nitrogen gas flow was 25 l hꢀ1
and the drying nitrogen 250 l hꢀ1, source temperature
100 ꢁC with a capillary voltage of 3.5 kV and cone voltage
20 V. The flow rate was 100 ll minꢀ1. Samples were dis-
solved in a 1:1 mixture of H2O/CH3CN.
˚
Selected bond lengths (A) and bond angles (ꢁ) for [PtCl(bdtp)](BPh4) Æ
CH3CN
Cation A
Pt(1)–N(1)
Pt(1)–N(4)
2.025(4)
1.999(5)
Pt(1)–S(1)
Pt(1)–Cl(1)
2.2616(12)
2.3168(14)
N(4)–Pt(1)–N(1)
N(4)–Pt(1)–Cl(1)
N(1)–Pt(1)–Cl(1)
179.44(17)
91.05(15)
88.47(11)
N(4)–Pt(1)–S(1)
N(1)–Pt(1)–S(1)
S(1)–Pt(1)–Cl(1)
91.87(15)
88.60(11)
174.97(5)
Cation B
Pt(2)–N(8)
Pt(2)–N(5)
2.008(4)
2.014(4)
Pt(2)–S(2)
Pt(2)–Cl(2)
2.2559(12)
2.3139(14)
N(8)–Pt(2)–N(5)
N(8)–Pt(2)–Cl(2)
N(5)–Pt(2)–Cl(2)
177.62(15)
91.06(11)
90.86(12)
N(8)–Pt(2)–S(2)
N(5)–Pt(2)–S(2)
S(2)–Pt(2)–Cl(2)
91.81(11)
86.42(11)
173.63(5)
˚
˚
Pt–Cl bond lengths [2.3168(14) A (cation A); 2.3139(15) A
(cation B)] can be regarded as normal compared with the
distances found in the literature. For Pt–Npz, the literature
describes values between 1.930 and 2.021 A [20], for
Pt–S(thioether) between 2.18 and 2.46 A [19,21], and for
˚
˚
˚
Pt–Cl between 2.198 and 2.381 A [20].
The Npz–Pt–S bite angles of the ligand are 91.87(15)ꢁ and
88.60(11)ꢁ (cation A) and 91.81(11)ꢁ and 85.42(11)ꢁ (cation
B), and are similar to the corresponding bite angles in the
complex [PdCl(bdtp)](BF4) (90.5(2)ꢁ and 88.5(2)ꢁ) [7c].
Samples of [PtCl2(CH3CN)2] [10] and [PtCl2(PhCN)2]
[11] were prepared as described in the literature. 1,5-
bis(3,5-dimethyl-1-pyrazolyl)-3,7-thiapentane (bdtp) [7c,8]
was prepared according to the published methods (Scheme
1).
3. Conclusion
Reaction of the bdtp ligand with different Pt(II) starting
materials forms different mixtures of the NN, NS and NSN
isomers. A similar reaction with [PdCl2(CH3CN)2] as the
starting material yielded the NN and NS isomers (the
NSN isomer was not observed with Pd before addition of
AgBF4) [7c] in a dynamic equilibrium in solution at room
temperature. This equilibrium is not observed for the Pt(II)
mixture on the NMR timescale (under the same condi-
tions), showing that Pt(II) forms more inert complexes with
bdtp than Pd(II).
In order to isolate the NSN isomer, we performed the
reaction of the bdtp mixture of isomers with NaBPh4,
obtaining [Pt(bdtp)](BPh4) as a pure product. In this case,
the only coordination observed is NSN (similar behaviour
to Pd(II)). When this product is refluxed in CH2Cl2/CH3OH
in the presence of Et4NBr a new mixture of NN, NS and
NSN isomers is obtained. This proves the hemilability of
this ligand with Pt(II) [1a], as was observed for Pd(II).
4.2. Reactions of bdtp with K2PtCl4 in H2O
0.23 mmol (0.065 g) of the bdtp ligand dissolved in
10 ml of water was added to a solution of 0.23 mmol
(0.095 g) of K2PtCl4 in 10 ml of water. The solution was
stirred at room temperature for 24 h (until the red colour
of the starting material K2PtCl4 had completely disap-
peared), and a yellow solid precipitated. It was filtered
off, washed twice with 5 ml of cold water and dried in
vacuum.
4.3. Reactions of bdtp with PtCl2
To 0.26 mmol (0.070 g) of PtCl2 in 15 ml of chloroform,
0.27 mmol (0.070 g) of the bdtp ligand dissolved in 15 ml of
the same solvent was quickly added. The mixture was
refluxed for 48 h. The yellowish solution was filtered to sep-
arate Pt(0) and the starting material PtCl2. The solvent was
evaporated to dryness leaving a white solid, which was fil-
tered off, washed with 10 ml of CH2Cl2/diethyl ether (1:1)
and dried in vacuum.
4. Experimental
4.1. General details
The reactions were carried out under nitrogen atmo-
sphere using vacuum line and Schlenk techniques. Solvents
were dried and distilled according to standard procedures
and stored under nitrogen. Elemental analyses (C, H, N, S)
were carried out by the staff of the Chemical Analyses
4.4. Reactions of bdtp with [PtCl2(CH3CN)2]
0.24 mmol (0.067 g) of the bdtp ligand dissolved in
15 ml of acetonitrile was added to a solution of 0.24 mmol
(0.085 g) PtCl2(CH3CN)2 in 15 ml of acetonitrile. The solu-

2504
A. de Leon et al. / Polyhedron 26 (2007) 2498–2506
tion was refluxed for 24 h. The solvent was evaporated to
dryness leaving a yellow solid, which was filtered off,
washed with 10 ml of CH2Cl2/diethyl ether (1:1) and dried
in vacuum.
ppm. NN: (14%) 5.92 [0.53H, s, CH(pz)], 5.30 [1.05H, m,
NpzCH2- CH2S], 2.79 [1.05H, m, NpzCH2CH2S], 2.52
[1.58H, s, CH3(pz)], 2.38 [1.58H, s, CH3(pz)] ppm.
13C{1H} NMR (CD3Cl solution, 63 MHz) d: NS + NSN
+ NN: 153.1–148.6 (pz-C), 143.6–142.2 (pz-C), 108.8,
107.4, 106.0, 105.1 (CH(pz)), 61.9–49.7 (NpzCH2CH2S),
38.6 (SCH2CH2S), 15.3–11.4 (CH3(pz)) ppm.
4.5. Reaction of bdtp with [PtCl2(PhCN)2]
0.20 mmol (0.055 g) of the bdtp ligand dissolved in
15 ml of chloroform was added to a solution of 0.20 mmol
(0.095 g) of [PtCl2(PhCN)2] in 15 ml of the same solvent.
The mixture was refluxed 24 h. From the yellow solution
the solvent was evaporated to dryness yielding a yellow
solid, which was filtered off, washed with 10 ml of
CH2Cl2/diethyl ether (1:1) and dried in vacuum.
4.5.3. bdtp + [PtCl2(CH3CN)2]
Yield: 68%. Anal. Calc. for C14H22N4SCl2Pt: C, 30.89;
H, 4.07; N, 10.29; S, 5.89. Found: C, 30.36; H, 4.38; N,
9.68; S, 5.91%. Conductivity (Xꢀ1 cm2 molꢀ1, 0.98 ·
10ꢀ3 M in DMF): 65. IR (KBr, cmꢀ1): 3147 m(C–H)ar,
2967, 2917 m(C–H)al, 1553 (m(C@C), m(C@N))ar, 1465,
1422 (d(C@C), d(C@N))ar, 1093, 1032 d(C–H)ip, 801 d(C–
H)oop. (Polyethylene, cmꢀ1): 444 m(Pt–N), 380 m(Pt–S),
333 m(Pt–Cl). 1H NMR (CDCl3 solution, 250 MHz) d:
NSN: (100%) 6.03 [2H, s, CH(pz)], 5.30/4.76 [2H/2H, m,
NpzCH2CH2S], 3.98/2.81 [2H/2H, m, NpzCH2CH2S], 2.67
[6H, s, CH3(pz)], 2.40 [6H, s, CH3(pz)] ppm. 13C{1H}
NMR (CD3Cl solution, 63 MHz) d: NSN: 153.2 (pz-C),
143.9 (pz-C), 108.9 (CH(pz)), 51.5 (NpzCH2CH2S), 38.6
(SCH2CH2S), 15.6, 12.5 (CH3(pz)) ppm.
4.5.1. bdtp + K2PtCl4
Yield: 93%. Anal. Calc. for C14H22N4SCl2Pt: C, 30.89;
H, 4.07; N, 10.29; S, 5.89. Found: C, 31.10; H, 4.33; N,
10.40; S, 5.51%. Conductivity (Xꢀ1 cm2 molꢀ1, 1.05 ·
10ꢀ3 M in DMF): 152. IR (KBr, cmꢀ1): 3159 m(C–H)ar,
2968, 2922 m(C–H)al, 1553 (m(C@C), m(C@N))ar, 1461,
1421 (d(C@C), d(C@N))ar, 1069, 1034 d(C–H)ip, 801 d
(C–H)oop. (Polyethylene, cmꢀ1): 442 m(Pt–N), 394 m(Pt–S),
326 m(Pt–Cl). 1H NMR (CDCl3 solution, 250 MHz) d:
NS: (59%) 5.83 [1H, s, CH(pz)], 5.76 [1H, s, CH(pz)],
5.25/4.41 [1H/1H, m, NpzCH2CH2S], 4.08 [2H, t,
NpzCH2CH2S], 3.43/2.90 [1H/1H, m, NpzCH2CH2S], 2.82
[2H, t, SCH2CH2S], 2.63 [3H, s, CH3(pz)], 2.34 [3H, s,
CH3(pz)], 2.24 [3H, s, CH3(pz)], 2.19 [3H, s, CH3(pz)]
ppm. NSN: (33%) 6.00 [1.12H, s, CH(pz)], 5.25/4.78
[1.12H/1.12H, m, NpzCH2CH2S], 3.98 [1.12H, m,
NpzCH2CH2S], 2.67 [3.36H, s, CH3(pz)], 2.40 [3.36H, s,
CH3(pz)] ppm. NN: (8%) 5.90 [0.27H, s, CH(pz)], 5.30
[0.55H, m, NpzCH2CH2S], 2.90 [0.55H, m, NpzCH2CH2S],
2.70 [0.82H, s, CH3(pz)], 2.38 [0.82H, s, CH3(pz)] ppm
13C{1H} NMR (CD3Cl solution, 63 MHz) d: NS + NSN +
NN: 153.3–147.9 (pz-C), 144.4–139.3 (pz-C), 108.8, 108.7,
106.0, 105.1 (CH(pz)), 62.0–48.6 (NpzCH2CH2S), 46.3–
32.4 (SCH2CH2S), 15.4–11.2 (CH3(pz)) ppm.
4.5.4. bdtp + [PtCl2(PhCN)2]
Yield: 56%. Anal. Calc. for C14H22N4SCl2Pt: C, 30.89;
H, 4.07; N, 10.29; S, 5.89. Found: C, 31.05; H, 4.40; N,
10.58; S, 5.74%. Conductivity (Xꢀ1 cm2 molꢀ1, 1.05 ·
10ꢀ3 M in DMF): 20. IR (KBr, cmꢀ1): 3181 m(C–H)ar,
2967, 2922 m(C–H)al, 1553 (m(C@C), m(C@N))ar, 1465,
1422 (d(C@C), d(C@N))ar, 1097, 1026 d(C–H)ip, 800 d
(C–H)oop. (Polyethylene, cmꢀ1): 443 m(Pt–N), 396 m(Pt–S),
328 m(Pt–Cl). 1H NMR (CDCl3 solution, 250 MHz) d:
NS: (67%) 5.80 [1H, s, CH(pz)], 5.76 [1H, s, CH(pz)],
5.24/4.39 [1H/1H, m, NpzCH2CH2S], 4.06 [2H, t,
NpzCH2CH2S], 3.44/2.90 [1H/1H, m, NpzCH2CH2S], 2.80
[2H, t, SCH2CH2S], 2.62 [3H, s, CH3(pz)], 2.34 [3H, s,
CH3(pz)], 2.23 [3H, s, CH3(pz)], 2.19 [3H, s, CH3(pz)]
ppm. NSN: (26%) 6.00 [0.78H, s, CH(pz)], 5.24/4.76
[0.78H/0.78H, m, NpzCH2CH2S], 3.98 [0.78H, m,
NpzCH2CH2S], 2.67 [2.33H, s, CH3(pz)], 2.40 [2.33H, s,
CH3(pz)] ppm. NN: (7%) 5.90 [0.22H, s, CH(pz)], 2.54
[0.65H, s, CH3(pz)], 2.38 [0.65H, s, CH3(pz)] ppm.
13C{1H} NMR (CD3Cl solution, 63 MHz) d: NS + NSN +
NN: 153.1–147.9 (pz-C), 143.6–139.3 (pz-C), 108.7, 106.0,
105.2, 105.1 (CH(pz)), 61.9–48.6 (NpzCH2CH2S), 46.3–
29.2 (SCH2CH2S), 15.3–11.2 (CH3(pz)) ppm.
4.5.2. bdtp + PtCl2
Yield: 70%. Anal. Calc. for C14H22N4SCl2Pt: C, 30.89; H,
4.07; N, 10.29; S, 5.89. Found: C, 31.16; H, 3.98; N, 9.95; S,
5.45%. Conductivity (Xꢀ1 cm2 molꢀ1, 1.12 · 10ꢀ3 M in
DMF): 46. IR (KBr, cmꢀ1): 3193 m(C–H)ar, 2964, 2930
m(C–H)al, 1555 (m(C@C), m(C@N))ar, 1465, 1418 (d(C@C),
d(C@N))ar, 1100, 1021 d(C–H)ip, 800 d(C–H)oop. (Poly-
ethylene, cmꢀ1): 441 m(Pt–N), 419 m(Pt–S), 328 m(Pt–Cl).
1H NMR (CDCl3 solution, 250 MHz) d: NS: (31%) 5.82
[0.57H, s, CH(pz)], 5.76 [0.57H, s, CH(pz)], 5.25/4.40
[0.57H/0.57H, m, NpzCH2CH2S], 4.07 [1.13H, t, NpzCH2
CH2S], 3.50/2.83 [0.57H/0.57H, m, NpzCH2CH2S], 2.81
[1.13H, t, SCH2CH2S], 2.63 [2.84H, s, CH3(pz)], 2.34
[2.84H, s, CH3(pz)], 2.23 [2.84H, s, CH3(pz)], 2.19 [2.84H,
s, CH3(pz)] ppm. NSN: (55%) 6.01 [2H, s, CH(pz)], 5.25/
4.76 [2H/2H, m, NpzCH2CH2S], 3.98/2.90 [2H/2H, m,
NpzCH2CH2S], 2.67 [6H, s, CH3(pz)], 2.40 [6H, s, CH3(pz)]
4.6. Complexes [PtCl(bdtp)](BPh4) (1)
A solution of NaBPh4 (0.14 mmol, 0.050 g) in 10 ml ace-
tonitrile/methanol 1:1 was added dropwise with vigorous
stirring to a solution of [PtCl2(bdtp)] (0.14 mmol, 0.075 g)
in 10 ml of acetonitrile/methanol 1:1. The solution was stir-
red at room temperature for 12 h. The yellowish solution
was filtered to separate NaCl. When the volume of the
resultant solution had been reduced to roughly 5 ml,

A. de Leon et al. / Polyhedron 26 (2007) 2498–2506
2505
diethyl ether (5 ml) was then added to induce precipitation.
The resulting precipitate was then filtered and washed with
5 ml diethyl ether.
crystallisation from an acetonitrile:n-pentane solution. A
prismatic crystal was selected and mounted on
a
MAR345 diffractometer with a image plate detector.
Unit-cell parameters were determined from 8310 reflec-
tions (3 < h < 31ꢁ) and refined by least-squares method.
Intensities were collected with graphite-monochromatised
Mo Ka radiation. 39970 reflections were measured in
the range 2.62ꢁ 6 h 6 30.00ꢁ, 20296 of which were non-
equivalent by symmetry (Rint(on I) = 0.039). 19908 reflec-
tions were assumed as observed applying the condition
I > 2r(I). Lorentz-polarisation but no absorption correc-
tions were made.
Yield: 79% (0.076 g). Anal. Calc. for C38H44N4SClPtB: C,
65.82; H, 4.72; N, 5.31; S, 5.41. Found: C, 65.80; H, 4.71; N,
5.74; S, 5.39%. MS (m/z) (%) = 509 (100%) [PtCl(bdtp)]+.
Conductivity (Xꢀ1 cm2 molꢀ1, 1.06 · 10ꢀ3 M in DMF): 90.
IR (KBr, cmꢀ1): 3442 m(C–H)ar, 2984, 2927 m(C–H)al, 1579,
1556 (m(C@C), m(C@N))ar, 1476, 1425 (d(C@C), d(C@N))ar,
1067, 1031 d(C–H)ip, 799 d(C–H)oop, 736 m(B–C). (Polyeth-
1
ylene, cmꢀ1): 442 m(Pt–N), 380 m(Pt–S), 326 m(Pt–Cl). H
NMR ([D6]acetone solution, 250 MHz) d: 7.31–6.78 [20H,
Ph], 6.22 [2H, s, CH(pz)], 5.19 [2H, ddd, NpzCH2CH2S],
4.87 [2H, ddd, NpzCH2CH2S], 3.79 [2H, ddd, NpzCH2-
CH2S], 3.38 [2H, ddd, NpzCH2CH2S], 2.66 [6H, s, CH3(pz)],
2.48 [6H, s, CH3(pz)] ppm. 13C{1H} NMR ([D6]acetone
solution, 63 MHz) d = 165.8–122.0 (Ph), 153.1 (pz-C),
144.8 (pz-C), 108.8 (CH(pz)), 50.5 (NpzCH2CH2S), 39.2
(NpzCH2-CH2S), 14.9 (CH3(pz)), 11.4 (CH3(pz)) ppm.
195Pt{1H} NMR (CD3CN solution, 77.42 MHz) d = singlet
at ꢀ1880 ppm.
The structure was solved by direct methods, using the
SHELXS computer program [22], and refined by the full-
matrix least-squares method with SHELX-97 computer
programs [23] using 39970 reflections (very negative
intensities were not assumed). The function minimised
P
2
2 2
was
wjjFoj ꢀ jFcj j where w = [r2(I) + (0.0444P)2 +
6.5332P]ꢀ1, and P = (jFoj + 2jFcj )/3. All H atoms were
computed and refined, using a riding model, with an isotro-
pic temperature factor equal to 1.2 times the equivalent
temperature factor of the atom to which they are linked.
The final R(F) factor and Rw(F2) values as well as the num-
ber of parameters and other details concerning the refine-
ment of the crystal structure are gathered in Table 3.
2
2
4.7. X-ray crystal structure for compound
[PtCl(bdtp)](BPh4) Æ CH3CN
Suitable crystals for X-ray diffraction of compound cis-
[PtCl(bdtp)](BPh4) Æ CH3CN were obtained through
5. Supplementary material
Table 3
CCDC 620335 contains the supplementary crystallo-
graphic 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 Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ,
UK; fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.
cam.ac.uk.
Crystallographic data for [PtCl(bdtp)](BPh4) Æ CH3CN
Empircal formula
Formula weight
Temperature (K)
Crystal system
Space group
Unit cell dimensions
C82H93B2Cl2N11Pt2S2
1779.49
293(2)
triclinic
ꢀ
P1
˚
a (A)
14.446(6)
15.306(6)
19.500(4)
88.71(2)
74.43(2)
76.08(2)
˚
b (A)
˚
c (A)
Acknowledgement
a (ꢁ)
b (ꢁ)
´
Support by the Spanish Ministerio de Educacion y Cul-
c (ꢁ)
3
˚
tura (Project BQU2003-03582) is gratefully acknowledged.
V (A )
4027(2)
Z
2
Dcalc (g cmꢀ3
)
1.467
3.638
1788
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F(000)
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