A novel route to multinuclear d8 metal-chalcogen compounds with nuclearity control

Article abstract of DOI:10.1002/ejic.200400257

We have designed a new synthetic procedure to obtain multinuclear aggregates containing a {Pt₂S₂}_n core. The synthetic strategy involves the reaction of [(dppp)Pt(μ-S) ₂Pt(dppp)] with [PtCl₂(PhCN)₂] and thus the expansion of the {Pt₂S₂} ring to a [{Pt₂S ₂}PtCl₂] fragment. The lability of the chloride anions allows their replacement by bridging sulfide ligands, thus affording a new [{Pt₂(μ₃-S)₂}{Pt₂(μ-S) ₂}{Pt₂(μ₃-S)₂}] core. Its subsequent evolution to [{Pt₂S₂}₃PtCl ₂] lays the foundation for a new cycle. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Full text of DOI:10.1002/ejic.200400257

SHORT COMMUNICATION
A Novel Route to Multinuclear d8 Metal؊Chalcogen Compounds with
Nuclearity Control
[a]
[b]
[a]
[a]
´
´
´
´
´
Ruben Mas-Balleste, William Clegg, Agustı Lledos,* and Pilar Gonzalez-Duarte*
Keywords: Cluster compounds / Platinum / Metalloligands / Self-assembly / Sulfur
We have designed a new synthetic procedure to obtain multi-
thus affording a new [{Pt2(µ3-S)2}{Pt2(µ-S)2}{Pt2(µ3-S)2}] core.
nuclear aggregates containing a {Pt2S2}n core. The synthetic Its subsequent evolution to [{Pt2S2}3PtCl2] lays the foundation
strategy involves the reaction of [(dppp)Pt(µ-S)2Pt(dppp)]
with [PtCl2(PhCN)2] and thus the expansion of the {Pt2S2}
ring to a [{Pt2S2}PtCl2] fragment. The lability of the chloride
anions allows their replacement by bridging sulfide ligands,
for a new cycle.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2004)
Introduction
evolution to [{Pt2S2}3PtLЈ2] lays the foundation for a new
cycle. In this work we present the synthesis and characteriz-
ation of three complexes derived from [Pt2(µ-S)2(dppp)2] (1;
Scheme 1) and provide evidence for the lability of chloride
ligands in the [{Pt2S2}PtCl2] fragment.
Preparation of novel structures in good yields by system-
atic approaches is relevant in transition-metal sulfide chem-
istry in view of the current interest and economic import-
ance of these compounds in industrial uses.[1] Although no-
vel approaches to the synthesis of high nuclearity platinum
complexes have been reported recently,[2] the chemistry of
noble-metalϪsulfido clusters has been neglected compared
with that of aggregates containing the first transition series
metals and molybdenum.[3] Here we report a novel syn-
thetic route based on the behavior of [L2Pt(µ-S)2PtL2] com-
pounds as metalloligands, which leads to multinuclear ag-
gregates containing a {Pt2S2}n core. The synthetic strategy
allows control of the nuclearity of the cluster and can be
extended to other metals with square-planar coordination.
The outstanding nucleophilicity of the sulfur atoms in the
{Pt2S2} core accounts for the significant number of known
homo- and heterometallic derivatives of [L2Pt(µ-S)2PtL2]
(L ϭ phosphane) identified to date,[4] as well as for its reac-
tion with organic electrophiles[5] and protons.[6] On the
basis of the ability of [L2Pt(µ-S)2PtL2] to act as a ligand to
metal centers, we now address the use of these compounds
for building up multinuclear aggregates containing a
{Pt2S2}n core. The synthetic strategy involves first expan-
sion of the {Pt2S2} rings to [{Pt2S2}PtLЈ2] fragments con-
taining labile terminal LЈ ligands, which are then replaced
by bridging sulfide ligands. As a result, the PtLЈ2 fragment
evolves to a {Pt2S2} linking unit between two {Pt2S2} rings,
thus affording a new [{Pt2S2}2{Pt2S2}] core. Its subsequent
Results and Discussion
The reaction of equimolar quantities of [Pt2(µ-
S)2(dppp)2] (1) and [PtCl2(PhCN)2] gave the compound
[{Pt2(µ3-S)2(dppp)2}PtCl2] (2) in good yield. The X-ray
crystal structure of this complex consists of discrete trinu-
clear species and solvent molecules. Although the latter
show disorder, the structure of the complex (Figure 1) has
been unequivocally determined. Thus, the central Pt3S2 unit
consists of a nonequilateral triangle of platinum atoms
capped above and below by two sulfur atoms, thus forming
a trigonal bipyramid. Each platinum atom has approximate
square-planar coordination. Significantly, among the wide
family of derivatives obtained from [L2Pt(µ-S)2PtL2] metal-
loligands (L ϭ phosphane) no previous example of the
P4Cl2Pt3S2 core observed in 2 has been observed by X-ray
diffraction. Thus, in the absence of X-ray data, three differ-
ent alternatives have been proposed as a result of synthetic
strategies similar to that followed for the synthesis of 2
(reaction R1). These are: formation of a mixture of
hexanuclear [{Pt2(µ3-S)2[P(tolyl)3]4}M2(µ-Cl)2{Pt2(µ3-S)2-
[P(tolyl)3]4}]2ϩ and trinuclear [{Pt2(µ3-S)2[P(tolyl)3]4}MCl2]
(M ϭ Pd, Pt) species,[7] or formation of only a hexanuclear
[{Pt2(µ3-S)2(PPh3)4}Pd2(µ-Cl)2{Pt2(µ3-S)2(PPh3)4}]2ϩ [8]
or
,
a trinuclear [{Pt2(µ3-S)2(PPh3)4}PtCl2][9] complex. The
[a]
´
`
Departament de Quımica, Universitat Autonoma de Barcelona,
31P{1H} NMR spectrum of 2 in CDCl3 shows only one
08193 Bellaterra, Barcelona, Spain
1
Fax: (internat.) ϩ 34-935-813-101
E-mail: Pilar.Gonzalez.Duarte@uab.es
School of Natural Sciences (Chemistry), University of Newcastle,
Newcastle upon Tyne NE1 7RU, UK
signal centered at δ ϭ Ϫ8.08 ppm with JPt,P ϭ 2978 Hz,
thus indicating that the 31P nuclei are equivalent in solution,
in agreement with the solid-state structure.
[b]
Eur. J. Inorg. Chem. 2004, 3223Ϫ3227
DOI: 10.1002/ejic.200400257
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3223

´
´
´
R. Mas-Balleste, W. Clegg, A. Lledos, P. Gonzalez-Duarte
SHORT COMMUNICATION
Scheme 1
The lability of the chloro ligands in 2 becomes apparent have been identified: [{Pt2(µ3-S)2(dppp)2}PtCl]ϩ (m/z ϭ
in the characterization of this compound by ESI-MS. Thus, 1509.5), [{Pt2(µ3-S)2(dppp)2}PtCl(CH3CN)]ϩ (m/z
ϭ
depending on the recording conditions and on the solvent 1550.8), [{Pt2(µ3-S)2(dppp)2}Pt(CH3CN)2]2ϩ (m/z ϭ 778.2),
used to obtain mass data, the following cationic species or [{Pt2(µ3-S)2(dppp)2}PtCl(CH3OH)]ϩ (m/z ϭ 1541.6).
3224
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2004, 3223Ϫ3227

Multinuclear d8 MetalϪChalcogen Compounds
SHORT COMMUNICATION
Figure 2. MALDI-TOF spectrum of 5 showing the major intensity
peak at m/z ϭ 3013.5 corresponding to [5 ϩ H]ϩ; experimental (a)
and simulated (b) isotope-distribution patterns are included; the
peak at m/z ϭ 2980 corresponds to [5 Ϫ S]ϩ
Figure 1. Molecular structure of 2 with the key atoms labeled and
50% probability ellipsoids; H atoms, phenyl rings and CH2Cl2 sol-
vent molecules have been omitted; selected structural parameters
˚
[A, °]: PtϪCl 2.330(7), Pt(1)ϪS 2.381(7), Pt(2)ϪS 2.357(6), Pt(3)ϪS
2.287(6), Pt(1)ϪP(1) 2.237(7), Pt(2)ϪP(2) 2.256(7), Pt(1)···Pt(2)
3.124(2), Pt(1)···Pt(3) 2.942(2), Pt(2)···Pt(3) 3.277(2), S···S 2.981;
ClϪPt(3)ϪCl 91.1(4), PϪPt(1)ϪP 93.6(4), PϪPt(2)ϪP 93.1(3),
SϪPt(1)ϪS 77.5(3), SϪPt(2)ϪS 78.5(3), SϪPt(3)ϪS 81.4(3); di-
hedral (hinge) angles between PtS2 planes: Pt(1)/Pt(2) 116.0, Pt(1)/
Pt(3) 110.1, Pt(2)/Pt(3) 134.0
from the ability of the former to displace the {PtCl2} frag-
ment from 2 to afford 1 and [{Pt2(µ3-S)2(dppp)2}Pt2(µ3-
S)2PtCl2{Pt2(µ3-S)2(dppp)2}] (6), as indicated in Scheme 1.
An alternative way to obtain 6 is by treating 5 with a stoi-
chiometric amount of [PtCl2(PhCN)2].
Complex 6 was characterized by mass spectrometry and
NMR spectroscopy. The MALDI-TOF spectrum has a
major signal at m/z ϭ 1640.2, which can be assigned to the
[6 ϩ 2 H]2ϩ cation (for the major peak, theoretical m/z ϭ
1640). Comparison of the experimental and theoretical iso-
tope-distribution patterns is given in Figure 3. 31P{1H}
NMR measurements of 6 in [D6]DMSO show a broad sig-
nal centered at δ ϭ Ϫ9.3 ppm with 1JPt,P of about 3000 Hz.
The broadness of this signal, which does not allow us to
distinguish the nonequivalence of the phosphorus nuclei,
can be attributed to the high number of possible couplings
between magnetically active platinum and phosphorus nu-
clei in 6. The 195Pt NMR spectrum consists of two singlets
(δ ϭ Ϫ3519, Ϫ3418 ppm) corresponding to the platinum
nuclei in the PtS4 and PtCl2S2 fragments, respectively, and
For the three species a good match between experimental
and theoretical isotope distribution has been observed, the
above m/z values corresponding to the major intensity peak.
Additional evidence for this lability is provided by the fact
that a solution of 2 in DMSO yields the unprecedented
complex [{Pt2(µ3-S)2(dppp)2}PtCl(dmso)]Cl (3), whose syn-
thesis and characterization is reported here. Moreover, the
addition of a stoichiometric amount of dppp to 2 affords
complex [Pt3(µ3-S)2(dppp)3]Cl2 (4), already obtained from
a different synthetic procedure.[6a]
On the basis of its ability to exchange the chloride ions,
the synthesis of [{Pt2(µ3-S)2(dppp)2}2{Pt2(µ-S)2}] (5) was
carried out by treating complex 2 with a stoichiometric
amount of Na2S·9H2O. The 31P{1H} NMR spectrum of 5
in [D6]DMSO shows a broad signal centered at δ ϭ
1
Ϫ7.9 ppm with a JPt,P value of ca. 3000 Hz, and the 195Pt
NMR spectrum in the same solvent consists of two signals,
one singlet at δ ϭ Ϫ3524 ppm (PtS4) and one triplet cen-
1
tered at δ ϭ Ϫ4425 ppm (S2PtP2) with JPt,P ϭ 3002 Hz.
Further evidence for the hexanuclear nature of 5 was pro-
vided by the MALDI-TOF mass spectrum, which shows a
complex isotope-pattern distribution with a major peak at
m/z ϭ 3013.5. As shown in Figure 2, both features are con-
sistent with the molecular mass of the cation [{Pt2(µ3-
S)2(dppp)2}Pt(µ-S)(µ-SH)Pt{Pt2(µ3-S)2(dppp)2}]ϩ, and thus
with the nature of complex 5.
Comparison of the nucleophilicity of the {Pt2S2} core in
complexes 5 and 1 was established by determination of their
basic character. Thus, titration of 1 and 5 with HCl was
monitored by 31P{1H} NMR spectroscopy. The addition of
a stoichiometric amount of HCl to 5 leads to 2 quantitat-
ively, while formation of [PtCl2(dppp)] from 1 requires a
significant excess of HCl.[6a] Additional evidence for the
Figure 3. MALDI-TOF spectrum of 6 showing the major intensity
peak at m/z ϭ 1640.3 corresponding to [6 ϩ 2 H]2ϩ; experimental
greater basicity of the {Pt2S2} core in 5 than in 1 comes (a) and simulated (b) isotope-distribution patterns are included
Eur. J. Inorg. Chem. 2004, 3223Ϫ3227
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3225

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R. Mas-Balleste, W. Clegg, A. Lledos, P. Gonzalez-Duarte
SHORT COMMUNICATION
two triplets — δ ϭ Ϫ4403 ppm (1JPt,P ϭ 2997 Hz) and δ ϭ
Ϫ4420 ppm (1JPt,P ϭ 2970 Hz) — which can be assigned to
the two different platinum nuclei present as S2PtP2 in 6.
The thermodynamic feasibility of the reactions given in
Scheme 1 has been corroborated by means of density func-
tional calculations performed for complexes 1, 2, 5 and 6,
where dppp is modeled by two PH3 ligands. The calculated
reaction energies are given in Table 1. Geometry optimi-
zation of 1t, 2t, 5t and 6t affords their structural data, that
NMR spectra were recorded from samples in (CD3)2SO solution
at room temperature, using a Bruker 250 spectrometer. 1H and 13
C
chemical shifts are relative to SiMe4, 31P chemical shifts to external
85% H3PO4 and 195Pt chemical shifts to external H2PtCl6. The ESI-
MS measurements were performed with a VG Quattro Micromass
Instrument. Experimental conditions are given elsewhere.[5]
MALDI mass spectra were obtained with a Voyager DE-RP (Per-
Septive Biosystems, Framighan) time-of-flight (TOF) mass spec-
trometer equipped with a nitrogen laser (337 nm, 3 ns pulse). The
accelerating voltage in the ion source was 20 kV. Data were ac-
of 2t being in good agreement with the crystallographically quired in the reflector mode operation with a delay time of 60 ns.
Experiments were performed using the matrix 2,5-dihydroxyben-
zoic acid (DHB; Aldrich). Matrix solutions were prepared by dis-
solving 10 mg of DHB in 10 mL of CH3CN/H2O 50% (v/v). Equal
volumes (1 µL ϩ 1 µL) of matrix solution and diluted samples
(10Ϫ2  in CH3CN) were mixed and spotted onto the stainless-steel
sample plate. The mixture was dried in air before being introduced
into the mass spectrometer. Microanalytical data have been omitted
because those referring to the carbon content were unsatisfactory,
as already reported in some related (phosphane)platinum com-
plexes.[5][6a][6b]
determined data for 2. As regards the HOMO orbitals of
1t and 5t, they essentially consist of an antibonding combi-
nation of pπ orbitals of the sulfur atoms pointing outwards
from the hinged {Pt2S2} ring, thus accounting for the ob-
served coordinating ability of the sulfur atoms. Interest-
ingly, the energy level of the HOMO for 5t (Ϫ2.46 eV) is
1.95 eV higher than for 1t (Ϫ4.41 eV), which is in agree-
ment with the greater basicity found experimentally for the
{Pt2S2} core in 5 than in 1.
Table 1. B3LYP reaction energies in the gas phase
Synthesis of [{Pt2(µ3-S)2(dppp)2}PtCl2] (2): The reaction of equimo-
lar quantities of [Pt2(µ-S)2(dppp)2] (1; 500 mg, 0.39 mmol) and
[PtCl2(PhCN)2] (184 mg, 0.39 mmol) in benzene (80 mL) at room
temperature for 6 h gave [{Pt2(µ3-S)2(dppp)2}PtCl2] (2) as an or-
ange solid, which was filtered off and washed with diethyl ether
(532 mg, yield 82%). Slow evaporation of the solvent from a solu-
tion of 2 in CH2Cl2 afforded yellow X-ray-quality crystals. 31P{1H}
NMR (CDCl3): δ ϭ Ϫ8.1 ppm (1JPt,P ϭ 2978 Hz). ESI-MS: m/z ϭ
1509.5 [M Ϫ Cl]ϩ.
Reaction
Energy [kcal/mol]
R1
Ϫ8.3
R3
Ϫ41.2
R4
Ϫ49.7
R5
Ϫ40.4
Conclusion
Synthesis of [{Pt2(µ3-S)2(dppp)2}PtCl(dmso)]Cl (3): Complex 2
(300 mg, 0.19 mmol) was dissolved in the minimum amount of
DMSO (1 mL). Addition of diethyl ether caused precipitation of
complex 3 as a yellowish solid, which was filtered off and washed
with diethyl ether (206 mg, yield 67%). 31P{1H} NMR (CDCl3):
In this work, we have provided a new insight into the
chemistry of [L2Pt(µ-S)2PtL2] compounds that goes beyond
their usual behavior as metalloligands towards a wide range
of transition metals. The synthetic route used demonstrates
that the nucleophilicity of the {Pt2S2} core can be driven to
build nuclearity-controlled multinuclear aggregates contain-
ing a {Pt2S2}n core. This strategy requires replacement of
δA ϭ Ϫ7.1 ppm (1JPt,P ϭ 3022 Hz); δB ϭ Ϫ7.8 ppm (1JPt,P
ϭ
B
3051 Hz). 1H NMR (CADCl3): δ ϭ 2.85 ppm (coordinated dmso).
13C NMR (CDCl3): δ ϭ 44.4 ppm (coordinated dmso). ESI-MS:
the terminal X ligands in [{Pt2S2}nPtX2] fragments. For m/z ϭ 1587.7 [M]ϩ.
X ϭ Cl, this has been achieved by reaction with sodium sul-
fide.
Characterization of the high nuclearity complexes here
obtained has required several spectroscopic techniques,
among which MALDI-TOF mass spectrometry has proved
very valuable despite its scarce use in coordination chemis-
try studies.
Finally, on the basis of these results it can be concluded
that a similar reaction scheme should be suitable for ob-
taining macromolecular complexes containing a {M2(µ-
S)2}n core provided M has a preference for square-planar
coordination environments.
Synthesis of [{Pt2(µ3-S)2(dppp)2}Pt2(µ-S)2{Pt2(µ3-S)2(dppp)2}] (5):
A suspension of complex 2 (400 mg, 0.25 mmol) in methanol (50
mL) was allowed to react with a stoichiometric amount of
Na2S·9H2O (61 mg, 0.25 mmol) at room temperature for 1 h. Con-
centration of the filtered orange solution thus obtained, followed
by addition of diethyl ether, allowed isolation and characterization
of the title compound (229 mg, yield 61%). 31P{1H} NMR
([D6]DMSO): δ ϭ Ϫ7.9 ppm. 195Pt NMR ([D6]DMSO): δ ϭ
Ϫ3524, Ϫ4425 ppm (1JPt,P ϭ 3000 Hz). MALDI: m/z ϭ 3013.5 [M
ϩ H]ϩ.
Synthesis
of
[{Pt2(µ3-S)2(dppp)2}Pt2(µ3-S)2PtCl2{Pt2(µ3-S)2-
(dppp)2}] (6): A solution of 5 (200 mg, 0.07 mmol) in acetonitrile
(50 mL) containing a stoichiometric amount of [PtCl2(PhCN)2]
(32 mg, 0.07 mmol) was left to react at room temperature for 3 h.
The red solution was filtered and the resulting filtrate concentrated.
The title compound was isolated after addition of diethyl ether
(123 mg, yield 54%). 31P{1H} NMR ([D6]DMSO): δ ϭ Ϫ9.3 ppm.
195Pt NMR ([D6]DMSO): δ ϭ Ϫ3519, Ϫ3418, Ϫ4403 ppm (1JPt,P ϭ
2997 Hz), Ϫ4420 (1JPt,P ϭ 2970 Hz) ppm; MALDI: m/z ϭ 1640.2
Experimental Section
General Remarks: All reactions were carried out under pure dini-
trogen, and conventionally dried and degassed solvents were used
throughout. Complex [PtCl2(dppp)] was prepared according to
published methods.[10] The synthesis of [(dppp)Pt(µ-S)2Pt(dppp)]
has already been reported.[5] 1H, 13C{1H} 31P{1H} and 195Pt{1H}
[M ϩ 2 H]2ϩ
.
3226
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Inorg. Chem. 2004, 3223Ϫ3227

Multinuclear d8 MetalϪChalcogen Compounds
SHORT COMMUNICATION
[2] [2a]
C. H. Tao, K. M.-C. Wong, N. Y. Zhu, V. W.-W. Yam, New
X-ray
Crystallographic
Study
of
Complex
2:
[2b]
J. Chem. 2003, 27, 150.
C.-K. Hui, B. W.-K. Chu, N. Zhu,
C54H52Cl2P4Pt3S2·6CH2Cl2, M ϭ 2054.7, orthorhombic, Pnma,
[2c]
V. W.-W. Yam, Inorg. Chem. 2002, 41, 6178.
B. T. Steren-
3
˚
˚
a ϭ 19.982(3), b ϭ 18.607(2), c ϭ 19.372(2) A, V ϭ 7202.5(16) A ,
Z ϭ 4, T ϭ 160 K, R ϭ 0.091. The molecule lies in a crystallo-
graphic mirror plane, as do some of the chloroform solvent
molecules, while others are in general positions. High displacement
parameters suggest possible disorder of the solvent molecules, but
this could be resolved only for one, in which one chlorine atom
occupies alternative sites on either side of a mirror plane while the
carbon atom and the other chlorine atom are in the plane. Re-
straints on geometry and displacement parameters were used to aid
the refinement. The crystallographic analysis was further compli-
cated by the probable occurrence of multiple twinning by exchange
among the unit cell axes, all three of which are similar in length;
this was indicated by an analysis of the agreement of observed and
calculated intensities, but it was not possible to find a simple
model for the twinning. This leads to the relatively high R factor.
CCDC-221226 contains the supplementary crystallographic data
for this paper. These data can be obtained free of charge at
www.ccdc.cam.ac.uk/conts/retrieving.html [or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge
CB2 1EZ, UK; Fax: (internat.) ϩ 44-1223-336-033; E-mail:
deposit@ccdc.cam.ac.uk].
berg, R. Ramachandran, R. J. Puddephatt, J. Cluster Sci. 2001,
[2d]
12, 49.
W. Schuh, G. Wachtler, G. Laschober, H. Kopacka,
K. Wurst, P. Peringer, Chem. Commun. 2000, 1181.
[3]
M. Hidai, S. Kuwata, Y. Mizobe, Acc. Chem. Res. 2000, 33, 46.
[4] [4a]
Z. Li, W. Zheng, H. Liu, K. F. Mok, T. S. A. Hor, Inorg.
[4b]
Chem. 2003, 42, 8481.
X. Xu, S.-W. A. Fong, Z. Li, Z.-H.
Loh, F. Zhao, J. J. Vittal, W. Henderson, S.-B. Khoo, T. S. A.
Hor, Inorg. Chem. 2002, 41, 6838.
sco, W. Clegg, R. A. Coxall, P. Gonzalez-Duarte, A. Lledos, J.
[4c]
M. Capdevila, Y. Carra-
´
´
[4d]
´
A. Ramırez, J. Chem. Soc., Dalton Trans. 1999, 3103.
S.-W.
A. Fong, T. S. A. Hor, J. Chem. Soc., Dalton Trans. 1999, 639
and references cited therein. [4e] V. W.-W. Yam, P. K.-Y. Yeung,
K.-K. Cheung, Angew. Chem. Int. Ed. Engl. 1996, 35, 739.
[5]
´
R. Mas-Balleste, M. Capdevila, P. A. Champkin, W. Clegg, R.
´
´
´
A. Coxall, A. Lledos, C. Megret, P. Gonzalez-Duarte, Inorg.
Chem. 2002, 41, 3218.
[6] [6a]
´
´
R. Mas-Balleste, G. Aullon, P. A. Champkin, W. Clegg, C.
´
´
´
Megret, P. Gonzalez-Duarte, A. Lledos, Chem. Eur. J. 2003, 9,
5023. [6b] G. Aullon, M. Capdevila, W. Clegg, P. Gonzalez-Du-
´
´
´
´
arte, A. Lledos, R. Mas-Balleste, Angew. Chem. Int. Ed. 2002,
41, 2776. [6c] S.-W. A. Fong, W. T. Yap, J. J. Vittal, T. S. A. Hor,
W. Henderson, A. G. Oliver, C. E. F. Rickard, J. Chem. Soc.,
[6d]
Dalton Trans. 2001, 1986.
S.-W. A. Fong, J. J. Vittal, W.
Henderson, T. S. A. Hor, A. G. Oliver, C. E. F. Rickard, Chem.
Commun. 2001, 421.
S. Narayan, V. K. Jain, Trans. Met. Chem. 2000, 25, 400.
C. E. Briant, T. S. A. Hor, N. D. Howells, D. M. P. Mingos, J.
Chem. Soc., Chem. Commun. 1983, 1118.
B. H. Aw, K. K. Looh, H. S. O. Chan, K. L. Tan, T. S. A. Hor,
J. Chem. Soc., Dalton Trans. 1994, 3177.
M. P. Brown, R. J. Puddephatt, M. Rashidi, K. R. Seddon, J.
Chem. Soc., Dalton Trans. 1977, 951.
Computational Details: Gas-phase DFT calculations with the
B3LYP functional were carried out using the Gaussian 98 suite of
programs.[11] Effective core potentials and their related double-ζ
basis set known as LANL2DZ were used for Pt, P, Cl and S atoms,
supplemented with polarization functions for P, Cl and S atoms.
The 6-31G basis set was used for H, C and N atoms with the ad-
dition of polarization functions for the N atom. A thermodynamic
consideration for the R2 reaction requires taking into account the
solvent effects. However, PCM calculation for compound 5 was
hindered by the size of the system and thus the reaction energy for
R2 could not be obtained.
[7]
[8]
[9]
[10]
[11]
M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M.
A. Robb., J. R. Cheeseman, V. G. Zakrzewski, J. A. Montgom-
ery, R. E. Stratmann, J. C. Burant, S. Dapprich, J. M. Millam,
A. D. Daniels, K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi,
V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C.
Adamo, S. Clifford, J. Ochterski, G. A. Petersson, P. Y. Ayala,
Q. Cui, K. Morokuma, D. K. Malick, A. D. Rabuck, K.
Raghavachari, J. B. Foresman, J. Cioslowski, J. V. Ortiz, B. B.
Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R.
Gomperts, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham,
C. Y. Peng, A. Nanayakkara, C. Gonzalez, M. Challacombe,
P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, J. L. Andres,
C. Gonzalez, M. Head-Gordon, E. S. Replogle, J. A. Pople,
Gaussian 98, Revission A.7, Gaussian Inc., Pittsburgh, PA,
1998.
Acknowledgments
Thanks are due to Prof. O. Rossell and I. Angurell for their assist-
ance in the recording of the 195Pt NMR spectra. Financial support
´
from the Ministerio de Ciencia y Tecnologıa of Spain (projects
BQU2001-1976 and BQU2002-04110-CO2-02) and the EPSRC
(UK) is gratefully acknowledged. R. M. B. is indebted to the Univ-
`
ersitat Autonoma de Barcelona for a pre-doctoral scholarship.
[1]
E. I. Stiefel, ACS Symp. Ser. 1996, 653, 2.
Received March 30, 2004
Eur. J. Inorg. Chem. 2004, 3223Ϫ3227
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 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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