Solid- and solution phase synthesis of diiminedichloroplatinum(II) complexes

Article abstract of DOI:10.1002/zaac.200600032

A solid-phase and solution phase synthesis approach for diiminedichloro complexes of platinum(II) was developed. In particular a dichloroplatinum(II) fragment was coordinated to the diimine ligands {4-[(pyridine-2-ylmethylene)- amino]-phenol, HO-N∩N′ (1); 4-[(pyridine-2-ylmethylene)-amino]- anisole, MeO-N∩N′ (2) and di-isopropylsilylpolystyrene immobilised 4-[(pyridine-2-ylmethylene)-amino]-phenolate PSO-N∩N′, (5)}. Identities of the compounds [Pt^IICl₂(HO-N∩N′)] (3), [Pt^IICl₂(MeO-N∩N′)] (4), [Pt ^IICl₂(PSO-N∩N′)] (6) and 3 obtained by cleavage from 6 were established by multinuclear NMR spectroscopy, by microanalysis and single-crystal diffraction (3 and 4). Structures of compounds 3 and 4 were discussed with the aid of DFT calculations.

Full text of DOI:10.1002/zaac.200600032

DOI: 10.1002/zaac.200600032
Solid- and Solution Phase Synthesis of Diiminedichloroplatinum(II) Complexes
Sven Reinhardt and Katja Heinze*
Heidelberg, Anorganisch-Chemisches Institut der Universität Heidelberg
Received February 6th, 2006.
Abstract. A solid-phase and solution phase synthesis approach for
diiminedichloro complexes of platinum(II) was developed. In
particular a dichloroplatinum(II) fragment was coordinated to the
[PtIICl2(MeOϪNʝNЈ)] (4), [PtIICl2(PSOϪNʝNЈ)] (6) and 3 obtai-
ned by cleavage from 6 were established by multinuclear NMR
spectroscopy, by microanalysis and single-crystal diffraction (3 and
4). Structures of compounds 3 and 4 were discussed with the aid
of DFT calculations.
diimine
ligands
(1);
{4-[(pyridine-2-ylmethylene)-amino]-phenol,
4-[(pyridine-2-ylmethylene)-amino]-anisole,
HOϪNʝNЈ
MeOϪNʝNЈ (2) and di-isopropylsilylpolystyrene immobilised
4-[(pyridine-2-ylmethylene)-amino]-phenolate PSOϪNʝNЈ, (5)}.
Identities of the compounds [PtIICl2(HOϪNʝNЈ)] (3),
Keywords: Solid-phase synthesis; Density functional calculations;
Diiminedichloroplatinum(II)
Introduction
Platinum(II) forms a wide variety of square planar d8 com-
plexes. The most important representative is cisplatin, cis-
[PtCl2(NH3)2], which is used as anticancer drug [1Ϫ3].
When using chelating diimines like substituted 2,2Ј- bipyri-
dines, phenanthrolines or bipyrimidines instead of am-
monia the electrochemical and photophysical behaviour of
the platinum compounds can be tuned [4Ϫ7].
Solid-phase synthesis of inorganic complexes is a rather
new discipline and was recently established by Heinze [8],
Metzler-Nolte [9] and Reedijk [10]. Previous attempts to ob-
tain (2,2Ј-bipyridine)-dichloro complexes of platinum(II)
via solid-phase synthesis by Gallop failed at the cleaving
step [11].
Herein we report a feasible way to synthesize diimine-
dichloroplatinum(II) complexes via solid-phase synthesis.
The solid-phase synthesis approach is compared with syn-
thesis in solution.
Scheme 1
Characterization of complexes 3 and 4
All compounds are unambiguously identified by a number
of methods. Formation of complexes 3 and 4 is proven by
FAB mass spectrometry which shows peaks of the molecu-
lar ions at m/z ϭ 464 (3) and m/z ϭ 478 (4) with expected
isotopic distributions. Typical fragmentations ([MϪCl]ϩ
and [MϪ2Cl]ϩ) are also observed.
The infrared spectra of these complexes are very similar.
Signals for the PtϪCl stretching vibrations are observed in
the far IR region at 334 and 307 cmϪ1 (3) and at 343 and
304 cmϪ1 (4), respectively. Interestingly, for 3 three bands
for the OϪH stretching vibrations are observed at 3559,
3419 and 3109 cmϪ1 suggesting hydrogen bonding in the
solid state. The higher energy bands are assigned to the
asymmetric and symmetric stretching vibrations of H2O hy-
drogen bonded to the OH-group (vide infra), while the low-
energy signal is assigned to the OH-stretching vibration of
the hydroxy group of the ligand.
Results and Discussion
Solution phase synthesis
The diimine ligands (HOϪNʝNЈ) (1) [8bϪd] and
(MeOϪNʝNЈ) (2) [12] were coordinated to a dichloro-
platinum(II) fragment by reaction with K2PtCl4 in
aqueous hydrochloric acid (Scheme 1). The products
([PtIICl2(HOϪNʝNЈ)] (3) and [PtIICl2(MeOϪNʝNЈ)] (4)
were isolated as orange solids in yields up to 78 %.
* Dr. Katja Heinze
Anorganisch-Chemisches Institut der Universität Heidelberg
Im Neuenheimer Feld 270, D-69120 Heidelberg
E-Mail: katja.heinze@urz.uni-heidelberg.de
Fax: ϩ49 6221 545707
This interpretation is additionally corroborated by ther-
mogravimetric analysis (TGA). For 3 three distinct mass
losses are observed. The first decomposition step at 68 °C
Z. Anorg. Allg. Chem. 2006, 632, 1465Ϫ1470
 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
1465

S. Reinhardt, K. Heinze
3
Table 1 Selected chemical shifts δ(1H) and JPt,H couplings in Hz
Table 2 Selected bond lengths (in A) and bond angles (in °) for 3
and 4.
˚
(in parentheses) of 1Ϫ4 in [D6]DMSO (atom numbering according
to Scheme 1).
3
4
H8
H6
H11
H10
H9
Pt1ϪCl1
Pt1ϪCl2
Pt1ϪN1
Pt1ϪN2
N1ϪPt1ϪN2
Cl1ϪPt1ϪCl2
N1ϪPt1ϪCl1
N1ϪPt1ϪCl2
N2ϪPt1ϪCl1
N2ϪPt1ϪCl2
2.292(3)
2.285(4)
2.01(1)
2.05 (1)
81.2(5)
88.8(1)
175.1(4)
95.6(4)
94.5(3)
176.1(3)
2.298(2)
2.282(2)
2.009(5)
2.014(6)
80.0(2)
88.91(7)
175.4(2)
95.7(2)
1
8.69
8.60
8.12
8.18
8.19
8.14
8.20
7.91
8.41
8.41
7.93
8.42
7.48
7.94
7.94
7.49
7.96
3
9.46 (19)
9.47 (19)
8.69
9.21 (40)
9.21 (40)
8.62
3a)
2
4
9.47 (19)
9.25 (46)
a) obtained from 6.
95.4(1)
174.8(1)
corresponds to the loss of one water molecule (obs. 4.0 %,
calcd. 3.7 %), the second step at 333 °C is assigned to the
loss of two chlorine atoms (obs. 13.2 %, calcd. 14.7 %) and
the third one at 457 °C fits to the loss of the diimine ligand
1 (obs. 44.7 %, calcd. 40.9 %). TGA of 4 shows only two
steps as expected: at 325 °C loss of two chlorine atoms (obs.
14.5 %, calcd. 14.8 %) and at 449 °C loss of ligand 2 (obs.
39.9 %, calcd. 44.6 %). In both cases elemental platinum re-
mains as residue.
Successful complexation of 1 and 2 to 3 and 4 is also
shown by NMR spectroscopy. Selected NMR spectroscopic
data are given in Table 1, for atom numbering see Scheme
1. Comparing the 1H NMR spectra of ligands 1 and 2 with
those of complexes 3 and 4 reveals significant differences:
(i) proton signals H6, H8, H9, H10 and H11 shift to lower
field and (ii) 195Pt satellites are observed for proton signals
H6 and H8. This finding is consistent with observations
made on phenanthroline PtII complexes [6]. The hydrogen
nuclei H8 and H6 experience the largest coordination shift:
0.78 ppm (4) and 0.77 ppm (3) for H8 and 0.63 ppm (4) and
0.61 ppm (3) for H6. Platinum-hydrogen coupling is ob-
Figure 1 Crystal structure and atom labeling of 3 (atom numbe-
ring is different from the data deposited).
3
served for both proton signals: JPt,H6 ϭ 40 Hz (3) and
3
46 Hz (4) and JPt,H8 ϭ 19 Hz (3 and 4). The remaining
hydrogen atoms of the pyridine ring (H9, H10 and H11)
experience a shift up to 0.50 ppm without observable plati-
num satellites. The 195Pt{1H} NMR resonances appear at
Ϫ2302 ppm (3) and Ϫ2305 ppm (4) further confirming the
successful complexation. These chemical shifts fall into a
typical region for dichloroplatinum(II) coordinated to
diimines [7, 10c, 13].
Figure 2 Crystal structure and atom labeling of 4 (atom numbe-
ring is different from the data deposited).
Single-crystal X-ray diffraction analyses
Single crystals of complexes 3 and 4 were obtained by dif-
fusion of diethyl ether in saturated DMSO solutions. Both
compounds crystallise in the triclinic space group P1. Table
2 summarizes selected bond lengths and bond angles and
the molecular structures are depicted in Figure 1 (3) and
Figure 2 (4).
The platinum ion possesses a nearly square planar en-
vironment (PtCl2N2) as expected for a d8 ion. The sum of
angles around platinum is 360° for 3 and 4. Only little dis-
tortions are caused by the chelating nature of the diimine
ligands. This fact leads to smaller N1ϪPt1ϪN2 angles
[81.2(5)° for 3 and 80.0(2)° for 4] and larger NϪPt1ϪCl
angles while the Cl1ϪPt1ϪCl2 angles [88.8(1)° for 3 and
88.91(7)° for 4] are nearly 90°. In both complexes the
Pt1ϪCl1 distances are slightly larger than the Pt1ϪCl2 dis-
tances due to the different trans influence of the different
nitrogen donor atoms.
¯
The hydroxy-functionalised complex 3 crystallises with
one DMSO molecule hydrogen-bonded to the OH-group of
the ligand. In the bulk material crystallised from water the
DMSO molecule is replaced by a water molecule (vide
supra). The distance between the oxygen atoms O1 and O2
˚
amounts to 2.68(5) A.
1466
www.zaac.wiley-vch.de
 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2006, 1465Ϫ1470

Solid- and Solution Phase Synthesis of Diiminedichloroplatinum(II) Complexes
˚
Table 3 Selected calculated and experimental bond lengths (in A)
and bond angles (in °) for 3.
3a)
3b)
3c)
3d)
3e)
Pt1ϪCl1
Pt1ϪCl2
Pt1ϪN1
Pt1ϪN2
N1-Pt1-N2
Cl1-Pt1-Cl2
N1-Pt1-Cl2
N2-Pt1-Cl1
2.399
2.392
2.052
2.044
80.0
89.1
97.5
2.384
2.377
2.054
2.047
79.9
89.1
97.4
2.333
2.327
2.062
2.055
79.3
89.7
97.2
2.332
2.326
2.062
2.054
79.7
89.6
97.0
2.292(3)
2.285(4)
2.01(1)
2.05 (1)
81.2(5)
88.8(1)
95.6(4)
94.5(3)
93.4
93.7
93.9
93.8
a) B3LYP/LanL2DZ; b) B3LYP/SDD; c) B3LYP/SDD (Pt), 6-31ϩG** (H, C,
Cl, N, O); d) B3LYP/SDD (H, C, O, Pt), 6-31ϩG** (Cl, N); e) experimental
data.
Figure 3 Absorption spectra of 3 during titration with phospha-
zene base P1-t-Bu in THF.
˚
Table 4 Selected calculated and experimental bond lengths (in A)
and bond angles (in °) for 4.
4a)
4b)
4c)
4d)
4e)
Pt1ϪCl1
Pt1ϪCl2
Pt1ϪN1
Pt1ϪN2
N1-Pt1-N2
Cl1-Pt1-Cl2
N1-Pt1-Cl2
N2-Pt1-Cl1
2.400
2.393
2.054
2.044
80.0
89.0
97.6
2.385
2.377
2.055
2.047
79.9
89.0
97.4
2.334
2.327
2.063
2.055
79.3
89.6
97.2
2.333
2.327
2.063
2.054
79.7
89.5
97.1
2.298(2)
2.282(2)
2.009(5)
2.014(6)
80.0(2)
88.91(7)
95.7(2)
93.4
93.6
93.8
93.7
95.4(1)
a) B3LYP/LanL2DZ; b) B3LYP/SDD; c) B3LYP/SDD (Pt), 6-31ϩG** (H, C,
Cl, N, O); d) B3LYP/SDD (H, C, O, Pt), 6-31ϩG** (Cl, N); e) experimental
data.
Scheme 2
titrated in THF with phosphazene base P1-t-Bu [15] and
subsequently acidified with acetic acid (Scheme 2). The re-
action processes were monitored by UV/Vis spectroscopy
(Figure 3). 3 shows five absorption bands at λmax (ε) ϭ 307
(5700), 363sh (6800), 392 (8700), 417sh (7900) and 454sh
(4700) nm. Addition of base leads to disappearance of four
bands and the growth of three new bands at λmax (ε) ϭ 290
(6700), 344 (5200) and circa 575 (300) nm. Isosbestic points
are observed at 284, 305, 316, 348 and 483 nm, suggesting
a simple equilibrium between two species.
Addition of acetic acid restores the original spectrum of
3 confirming the reversibility of the equilibrium shown in
Scheme 2. However, using trifluoroacetic acid (often em-
ployed in solid-phase syntheses as cleaving reagent [10bϪe,
11]) instead of acetic acid results in irreversible processes
(probably chloride displacement). The findings prove the
stability of 3 under alkaline conditions providing the pre-
requisite for the solid-phase synthesis approach.
Quantum chemical calculations
To obtain a benchmark for the quality of different basis
sets the structures of 3 and 4 were calculated using the
Gaussian03 program package [14]. The B3LYP (Becke 3-
parameter-Lee-Yang-Parr) [14] exchange correlation func-
tional was employed. Four different basis set combinations
were used and compared: a) LanLD2Z [14] for all atoms,
b) SDD [14] for all atoms, c) SDD for platinum and 6-
31ϩG** [14] for the main group elements and d) 6-31ϩG**
for nitrogen and chlorine and SDD for the remaining ele-
ments. Table 3 and 4 summarise selected data of calculated
and experimental structures. The overall geometry is well
reproduced with all basis sets employed, as expected for a
chelate system.
The following discussion focuses on the PtϪX bond
lengths. Calculated PtϪN distances match well the exper-
imental values for all models employed. However, PtϪCl
distances improve significantly with increasing basis set size.
The best compromise between accuracy and calculation
time seems to be the combination of basis sets 6-31ϩG**
(for N and Cl) and SDD (for C, H, O and Pt).
Solid-phase synthesis
For this approach a system consisting of an insoluble poly-
mer and a linker is required. The system must meet the
following criteria: (i) reproducible synthesis, (ii) stability un-
der the reaction conditions and (iii) feasible cleavage con-
ditions. A system composed of a polystyrene/divinylbenzene
copolymer resin and a silyl ether linker is compatible with
the synthesis and cleavage of metal complexes [8]. The resin
Stability of 3 under alkaline conditions
For the anticipated solid-phase synthesis including cleavage
under alkaline and slightly acidic conditions complex 3
should display an adequate stability. On this account 3 was
Z. Anorg. Allg. Chem. 2006, 1465Ϫ1470
 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1467

S. Reinhardt, K. Heinze
Scheme 3
is functionalised in three steps (Scheme 3): lithiation, silyl-
ation and coupling of deprotonated 1 giving the yellow im-
mobilised ligand (PSOϪ NʝNЈ) 5 with ligand loadings of
1.05 mmol ligand gϪ1 polymer (the polymer/linker system
is herein abbreviated with PS). The successful coupling was
corroborated by EI mass spectrometry displaying signals at
m/z ϭ 414, 371, 343 and 329, which are assigned to the
fragment ions [C8H7Si(iPr)2(OϪNʝNЈ)]ϩ, [C8H7Si-
(iPr)2(OϪNʝNЈ) Ϫ iPr]ϩ, [C8H7Si(iPr)2(OϪNʝNЈ) Ϫ iPr
Ϫ C2H4]ϩ, [C8H7Si(iPr)2(OϪNʝNЈ) Ϫ 2iPr ϩ H]ϩ, respec-
tively [8a].
Contrary to the syntheses in solution reaction of 5 with
K2PtCl4 was accomplished in a HClaq (0.4 M)/toluene (1/1)
mixture to guarantee sufficient swelling of the resin (tolu-
ene) and prevent chloride dissociation (HCl). The di-isopro-
pylsilyl linker and the diimine ligand are stable under these
conditions. After four hours the orange resin 6 was col-
lected and washed with water, ethyl alcohol and diethyl
ether.
Scheme 4
employed to find a suitable basis set for theoretical calcu-
lations (DFT). The hydroxy-functionalised complex 3 pro-
ves to be stable under alkaline and slightly acidic (acetic
acid) conditions which is premise for the solid-phase syn-
thesis of diiminedichloroplatinum(II) complexes employing
a silyl ether linker cleavable by fluoride ions. The successful
synthesis of 3 by solid-phase synthesis is corroborated by
1H NMR and UV/Vis spectroscopy as well as mass spectro-
metric analyses. The solid-phase synthesis of diimineplati-
num(II) complexes is thus established and is currently
extended to multinuclear platinum(II) complexes in our
laboratory.
Experimental Part
Solid-phase reactions were carried out under inert conditions. Sol-
vents were dried by standard methods and distilled under argon
prior to use. HOϪNʝNЈ (1) [8bϪd], MeOϪNʝNЈ (2) [12] and
PSOϪNʝNЈ (5) [8bϪd] were prepared by literature methods. All
other reagents were used as received from commercial sources.
Polystyrene resins cross-linked with 1 % divinylbenzene and with a
ligand loading of 1.05 mmol gϪ1 were used (5). For the solid-phase
reactions a flask with a nitrogen inlet and a coarse porosity fritted
glass filter that allows addition and removal of reagents and sol-
vents without exposure of the resin to the atmosphere was used.
IR spectra were recorded on a BioRad Excalibur FTS 3000 spec-
trometer using caesium iodide disks. UV/Vis spectra were recorded
on a Perkin Elmer Lambda 19 in 1.0 cm cells (Hellma, suprasil).
Mass spectra were recorded on a Finnigan MAT 8400 spec-
trometer, electron energy 70 eV (EI), 4-nitrobenzyl alcohol matrix
(FAB). Elemental analyses were performed by the microanalytical
laboratory of the Organic Chemistry Department, University of
Heidelberg. NMR spectra were obtained on a Bruker Avance DPX
200 (200.13 MHz (1H), 50.33 MHz (13C) and 42.92 MHz (195Pt) at
30 °C. Chemical shifts (δ) are reported in ppm with respect to re-
sidual solvent peaks as internal standards: [D6]DMSO (1H: δ ϭ
2.50; 13C: δ ϭ 39.4). 195Pt NMR shifts are reported relative to
To release complex 3 from the support 6 was treated with
tetrabutylammonium fluoride (TBAF). The fluoride ions
nucleophilic attack the silyl ether linkage. After acidifi-
cation with acetic acid 3 is obtained by simple filtration.
The identity of 3 was proven by mass spectrometry, NMR
and UV/Vis spectroscopy (Table 1 and Experimental Part).
The remaining silyl fluoride containing polymer 7 was ana-
lysed by EI mass spectrometry confirming the successful
silyl fluoride formation (Scheme 4). Signals at m/z ϭ 236,
193 and 165 are observed which are assigned to the frag-
ment ions [C8H7(iPr)2SiF]ϩ, [C8H7(iPr)2SiF Ϫ iPr]ϩ, and
[C8H7(iPr)2SiF Ϫ iPr Ϫ C2H4]ϩ, respectively [8a].
Conclusions
Two diiminedichloroplatinum(II) complexes (3 and 4) were
prepared in solution and spectroscopically characterised.
Their solid state structures were determined by X-ray dif-
fraction and the experimental geometrical parameters were
1468
www.zaac.wiley-vch.de
 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2006, 1465Ϫ1470

Solid- and Solution Phase Synthesis of Diiminedichloroplatinum(II) Complexes
H2PtCl6 at 0 ppm by use of an external reference of K2PtCl4 in
D2O (Ϫ1614 ppm relative to H2PtCl6) [10c, 16]. Cyclic voltamme-
try was performed on a Metrohm “Universal Mess- und Titrierge-
faess“, Metrohm GC electrode RDE 628, platinum electrode, SCE
electrode, Princeton Applied Research potentiostat Model 273; in
0.1 M nBu4NPF6/CH2Cl2. All potentials are given relative to that
of SCE. Thermogravimetric measurements were carried out on a
Mettler TC 15, heating rate 10 °C minϪ1 under argon from
30Ϫ800 °C.
(105 mg, 0.25 mmol) and 1 ml of 4 M hydrochloric acid was added
to the suspension and stirred for 4 h at 120 °C. After cooling to
room temperature the orange resin was filtered off and washed with
an excess of water, ethanol, diethyl ether and dried in vacuo.
Yield: 228 mg.
Cleavage of immobilised [PtIICl2(HO؊NʝNЈ)] (3)
from 6
Synthesis of [PtIICl2(HO؊NʝNЈ)] (3)
[PtIICl2(PSOϪNʝNЈ)] (6) (80 mg) was stirred slowly for 1 h in
20 ml CH2Cl2. nBu4NFႧ3H2O (19 mg, 0.06 mmol) was added to
the mixture. After 20 min the resin was filtered off and the filtrate
was carefully acidified with acetic acid. After removing the solvent
in vacuo the residue was washed with diethyl ether and dried in
vacuo.
HOϪNʝNЈ (1) (99 mg, 0.50 mmol) was added to a solution of
K2PtCl4 (200 mg, 0.50 mmol) in 15 ml water acidified with 1 ml
4 M hydrochloric acid and stirred for 1 h at 100 °C. After cooling
to room temperature the orange precipitate was filtered off and
washed with water (2 x 15 ml), 2 ml of cold methanol, diethyl ether
(2 x 15 ml) and dried in vacuo. Yield: 190 mg (78 %).
1H NMR ([D6]DMSO): δ ϭ 9.94(s, 1H, H1), 9.47 (dsat
,
3JPt,H ϭ 19 Hz,
,
3JPt,H ϭ 40 Hz, 1H, H6), 8.41 (pt,
3JH8,H9 ϭ 5 Hz, 1H, H8), 9.21 (ssat
3JH10,H9 ϭ 7 Hz, 3JH10,H11 ϭ 7 Hz, 1H, H10), 8.19 (d, 3JH11,H10 ϭ 7 Hz, 1H,
H11), 7.94 (pt, 3JH9,H10 ϭ 7 Hz, 3JH9,H11 ϭ 7 Hz, 1H, H9), 7.34 (d, 3JH4,H3 ϭ
9 Hz, 2H, H4), 6.83 (d, 3JH3,H4 ϭ 9 Hz, 2H, H3). MS (FAB-neg): m/z (%) ϭ
463 (46) [MϪH]Ϫ. UV/VIS (THF): λmax: 306, 361, 394, 418 and 452 nm.
Anal. found: C, 29.83; H, 2.60; N, 5.85 %. Anal. calcd. for
C12H10Cl2N2OPt (464.21): C, 31.05; H, 2.17; N, 6.03 %. Anal.
calcd. for C12H10Cl2N2OPtႧH2O (482.22): C, 29.88; H, 2.51; N,
5.81 %.
1H NMR ([D6]DMSO): δ ϭ 9.91 (s, 1H, H1), 9.46 (dsat 3JPt,H ϭ 19 Hz,
,
3JH8,H9 ϭ 5 Hz, 1H, H8), 9.21 (ssat 3JPt,H ϭ 40 Hz, 1H, H6), 8.41 (pt,
,
3JH10,H9 ϭ 7 Hz, 3JH10,H11 ϭ 7 Hz, 1H, H10), 8.18 (d, 3JH11,H10 ϭ 7 Hz, 1H,
Computational methods
H11), 7.94 (pt, 3JH9,H10 ϭ 7 Hz, 3JH9,H11 ϭ 7 Hz, 1H, H9), 7.34 (d, 3JH4,H3 ϭ
3
9 Hz, 2H, H4), 6.82 (d, JH3,H4
ϭ
9 Hz, 2H, H3). 13C{1H} NMR
Density functional calculations were carried out with the Gaus-
sian03 program package [14]. The B3LYP formulation of density
functional theory was used employing the SDD, LanL2DZ and 6-
31ϩG** basis sets, respectively [14]. For platinum quasirelativistic
effective core pseudopotentials and corresponding optimised sets
of basis functions were used [17]. Harmonic vibrational frequencies
were calculated by numerical second derivatives using analytically
calculated first derivatives.
([D6]DMSO): δ ϭ 170.3 (s, C7), 158.0 (d, C6), 157.2 (s, C2), 148.7 (d, C8),
140.4 (s, C5), 139.0 (d, C10), 129.1 (d, C11), 128.9 (d, C9), 125.6 (d, C4),
114.3 (d, C3). 195Pt{1H} NMR ([D6]DMSO): δ ϭ Ϫ2302 (s). IR (CsI): 3559
(s), 3419 (s), 3109 (s), 3064 (s), 1609 (s), 1507 (s), 334 (s), 307 (w) cmϪ1. MS
(FAB-pos): m/z (%) ϭ 464 (23) [M]ϩ, 429 (56) [MϪCl]ϩ, 392 (46) [MϪ2Cl]ϩ.
UV/VIS (THF): λmax (ε): 307 (5700), 363sh (6800), 392 (8700), 417sh (7900)
and 454sh (4700) nm. TGA: ∆m/m ϭ 4.0 % (calcd. 3.7 %) [68 °C, ϪH2O],
13.2 % (calcd. 14.7 %) [333 °C, Ϫ2Cl], 44.7 % (calcd. 40.9 %) [457 °C, Ϫ1].
CV: Ep ϭ Ϫ1260 mV (irr.). Mp. ϭ 331 Ϫ 335 °C (dec.).
Synthesis of [PtIICl2(MeO؊NʝNЈ)] (4)
Crystallographic structure determinations
MeOϪNʝNЈ (2) (107 mg, 0.50 mmol) was added to a solution of
K2PtCl4 (200 mg, 0.50 mmol) in 15 ml water acidified with 1 ml
4 M hydrochloric acid and stirred for 1 h at 100 °C. After cooling
to room temperature the orange precipitate was filtered off and
washed with water (2 x 15 ml), 2 ml of cold methanol, diethyl ether
(2 x 15 ml) and dried in vacuo. Yield: 164 mg (68 %).
The measurements were carried out with an Enraf-Nonius Kappa
CCD diffractometer using graphite monochromated Mo-Kα radi-
ation. The data were processed using the standard Nonius software
[18]. All calculations were performed using the SHELXT PLUS
software package. Structures were solved using direct or Patterson
methods with the SHELXS-97 program and refined with the
SHELXS-97 program [19]. Graphical handling of the structural
data during refinement was performed using XMPA [20] and Win-
Ray [21]. Atomic coordinates and anisotropic thermal parameters
of non-hydrogen atoms were refined by full-matrix least-squares
calculations. Data relating to the structure determinations are col-
lected in Table 5. Crystallographic data for the structures have been
deposited with the Cambridge Crystallographic Data Centre,
CCDC 295964 (3) and CCDC 295965 (4). Copies of the data can
be obtained free of charge on application to The Director, CCDC,
12 Union Road, Cambridge CB2 1EZ, UK (Fax: int.code
ϩ (1223)336-033; e-mail for inquiry: fileserv@ccdc.cam.ac.uk;
e-mail for deposition: deposit@ccdc.cam.ac.uk).
Anal. found: C, 32.62; H, 2.61; N, 5.81; Cl, 14.59 %. Anal. calcd.
for C13H12Cl2N2OPt (480.23): C, 32.65; H, 2.52; N, 5.86; Cl,
14.83 %.
3
1H NMR ([D6]DMSO): δ ϭ 9.47 (dsat
,
3JPt,H ϭ 19 Hz, JH8,H9 ϭ 6 Hz, 1H,
3
H8), 9.25 (ssat
,
3JPt,H ϭ 46 Hz, 1H, H6), 8.42 (pt, JH10,H9 ϭ 8 Hz,
3JH10,H11 ϭ 8 Hz, 1H, H10), 8.20 (d, JH11,H10 ϭ 8 Hz, 1H, H11), 7.96 (pt,
3
3JH9,H10 ϭ 6 Hz, JH9,H11 ϭ 6 Hz, 1H, H9), 7.45 (d, JH4,H3 ϭ 9 Hz, 2H,
3
3
H4), 7.03 (d, JH3,H4 ϭ 9 Hz, 2H, H3) , 3.83 (s, 1H, H1). 13C{1H} NMR
3
([D6]DMSO): δ ϭ 171.0 (s, C7), 159.4 (d, C6), 157.1 (s, C2), 148.7 (d, C8),
140.4 (s, C5), 140.1 (d, C10), 129.2 (d, C11), 129.1 (d, C9), 125.6 (d, C4),
113.1 (d, C3), 55.4 (q, C1). 195Pt{1H} NMR ([D6]DMSO): δ ϭ Ϫ2305 (s).
IR (CsI): 3103 (w), 3032 (s), 2845 (m), 1604 (s), 1504 (s), 1254 (s), 343 (s),
304 (w) cmϪ1. MS (FAB-pos): m/z (%) ϭ 478 (30) [M]ϩ, 443 (96) [MϪCl]ϩ,
406 (46) [MϪ2Cl]ϩ. UV/VIS (THF): λmax (ε): 306 (5800), 362sh (7500), 386
(8600), 417sh (6700) and 453 (4200) nm. TGA: ∆m/m ϭ 14.5 % (calcd.
14.8 %) [325 °C, Ϫ2Cl], 39.9 % (calcd. 44.6 %) [449 °C, Ϫ2]. CV: Ep
Ϫ1160 mV (irr.). Mp. ϭ 323Ϫ327 °C (dec.).
ϭ
Acknowledgement. This work was supported by the Deutsche
Forschungsgemeinschaft (Graduate College 850ϪModeling of Mo-
lecular Properties). The permanent, generous support from Prof.
Dr. G. Huttner is gratefully acknowledged. We thank Christina
Haaf for preparative assistance.
Synthesis of [PtIICl2(PSO؊NʝNЈ)] (6)
PSOϪNʝNЈ (5) (217 mg, 0.23 mmol, 1.05 mmol gϪ1) was stirred
slowly for 1 h in a mixture of 5 ml toluene and 5 ml water. K2PtCl4
Z. Anorg. Allg. Chem. 2006, 1465Ϫ1470
 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.zaac.wiley-vch.de
1469

S. Reinhardt, K. Heinze
G. A. van der Marel, J. H. van Boom, J. Reedijk, Angew.
Chem. 2000, 112, 3226; Angew. Chem., Int. Ed. 2000, 39, 3096.
(c) M. S. Robillard, J. S. Leith, G. A. van der Marel, J. H. van
Boom, J. Reedijk, Eur. J. Inorg. Chem. 2003, 1529. (d) M. S.
Robillard, M. Bacac, H. van den Elst, A. Flamigni, G. A. van
der Marel, J. H. van Boom, J. Reedijk, J. Comb. Chem. 2003,
5, 821. (e) S. van Zutphen, M. S. Robillard, G. A. van der
Marel, H. S. Overkleeft, H. den Dulk, J. Brouwer, J. Reedijk,
Chem. Commun. 2003, 634.
Table 5 Crystal data and details on the structure determinations
of complexes 3 and 4.
3
4
Empirical formula
Formula weight
Crystal system
Space group
Unit cell dimensions
C14H16Cl2N2O2PtS
542.34
triclinic
C13H12Cl2N2OPt
478.23
triclinic
¯
¯
P1
P1
˚
˚
˚
a ϭ 8.0790(16) A
b ϭ 10.115(2) A
c ϭ 11.550(2) A
a ϭ 8.4510(17) A
b ϭ 8.6210(17) A
c ϭ 9.978(2) A
˚
˚
[11] S. Tadesse, A. Bhandari, M. A. Gallop, J. Comb. Chem. 1999,
˚
1, 184.
Ͱ ϭ 72.38(3)°
β ϭ 80.13(3)°
γ ϭ 67.20(3)°
Ͱ ϭ 77.49(3)°
β ϭ 80.03(3)°
γ ϭ 78.61(3)°
[12] G. Matsubayashi, M. Okunaka, T. Tanaka, J. Organomet.
Chem. 1973, 56, 215.
[13] C. E. Keefer, R. D. Bereman, S. T. Purrington, B. W. Knight,
3
3
˚
˚
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
827.7(3) A
2
689.2(3) A
2
P. D. Boyle, Inorg. Chem. 1999, 38, 2294.
2.176 g/cm3
8.932 mmϪ1
516
2.305 g/cm3
10.559 mmϪ1
448
[14] M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M.
A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven,
K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J.
Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N.
Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K.
Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y.
Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H.
P. Hratchian, J. B. Cross, C. Adamo, J. Jaramillo, R. Gom-
perts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C.
Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A.
Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dap-
prich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick,
A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz,
Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov,
G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L. Martin,
D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayak-
kara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen,
M. W. Wong, C. Gonzalez, J. A. Pople, Gaussian 03, Revision
B.03, Gaussian, Inc., Pittsburgh PA, 2003.
θ range
Reflections collected
Independent reflections
1.85 Ϫ 27.56°
2.11 Ϫ 27.52°
5519
4798
3688 (Rint ϭ 0.0816)
3149 (Rint ϭ 0.0368)
3149/0/175
1.023
Data/restraints/parameters 3688/0/204
Goodness-of-fit on F2
R indices [I>2σ(I)]
1.018
R1 ϭ 0.0753,
wR2 ϭ 0.1800
R1 ϭ 0.1072,
wR2 ϭ 0.2016
R1 ϭ 0.0375,
wR2 ϭ 0.0832
R1 ϭ 0.0474,
wR2 ϭ 0.0877
R indices (all data)
Ϫ3
Ϫ3
˚
˚
1.902 and Ϫ2.770 eA
Largest diff. peak and hole 2.388 and Ϫ3.299 eA
References
[1] B. Rosenberg, L. Van Camp, J. E. Trosko, V. H. Mansour,
Nature 1969, 222, 385.
[2] M. L. Conrad, J. E. Enman, S. J. Scales, H. Zhang, C. M.
Vogels, M. T. Saleh, A. Decken, S. A. Westcott, Inorg. Chim.
Acta 2005, 358, 63.
[15] (a) R. Schwesinger, Nachr. Chem. Technol. Lab. 1990, 38, 1212.
(b) R. Schwesinger, C. Hasenfratz, H. Schlemper, L. Walz, E.
M. Peters, K. Peters, H. G. von Schnering, Angew. Chem.
1993, 105, 1420; Angew. Chem. Int. Ed. 1993, 32, 1361.
[16] P. S. Pregosin, Coord. Chem. Rev. 1982, 44, 247.
[17] D. Andrae, U. Häußermann, M. Dolg, H. Stoll, H. Preuß,
Theor. Chim. Acta 1990, 77, 123.
[3] J. Reedijk, Chem. Rev. 1999, 99, 2499.
[4] E. J. L. McInnes, R. D. Farley, C. C. Rowlands, A. J. Welch,
L. Rovatti, L. J. Yellowlees, J. Chem. Soc., Dalton Trans.
1999, 4203.
[5] T. J. Egan, K. R. Koch, P. L. Swan, C. Clarkson, D. A. Van
Schalkwyk, P. J. Smith, J. Med. Chem. 2004, 47, 2926.
[6] F. P. Fanizzi, G. Natile, M. Lanfranchi, A. Tiripicchio, F.
Laschi, P. Zanello, Inorg. Chem. 1996, 35, 3173.
[18] R. Hoft, Collect, Data Collection Software, Nonius, The
Netherlands, 1998; http://www.nonius.com
[7] A. Gaballa, C. Wagner, H. Schmidt, D. Steinborn, Z. Anorg.
Allg. Chem. 2003, 629, 703.
[19] G. M. Sheldrick, SHELXS-97, Program for Crystal Structure
Solution, University of Göttingen, Germany, 1997; http://
shelx.uni-ac.gwdg.de/SHELX/; G. M. Sheldrick, SHELXS-97,
Program for Crystal Structure Refinement, University of
Göttingen, Germany, 1997; http://shelx.uni-ac.gwdg.de/
SHELX/; International Tables for X-ray Crystallography,
Kynoch Press, Birmingham, U. K., 1974, vol. 4.
[8] (a) K. Heinze, T. Jannack, U. Winterhalter, Chem. Eur. J. 2000,
6, 4203. (b) K. Heinze, Chem. Eur. J. 2001, 7, 2922. (c) K.
Heinze, J. D. Bueno Toro, Angew. Chem. 2003, 115, 4671;
Angew. Chem., Int. Ed. 2003, 42, 4533. (d) K. Heinze, J. D.
Bueno Toro, Eur. J. Inorg. Chem. 2004, 3498.
[9] N. Metzler-Nolte, Angew. Chem. 2001, 113, 1072; Angew.
Chem., Int. Ed. 2001, 40, 1040.
[10] (a) K. S. Schmidt, D. V. Filippov, N. J. Meeuwenoord, G. A.
van der Marel, J. H. van Boom, B. Lippert, J. Reedijk, Angew.
Chem. 2000, 112, 383; Angew. Chem., Int. Ed. 2000, 39, 375.
(b) M. S. Robillard, A. R. P. M. Valentijn, N. J. Meeuwenoord,
[20] L. Zsolnai, G. Huttner, XMPA, University of Heidelberg,
Germany, 1998; http://www.chemgeo.uni-hd.de/AC/huttner/
frame/framesoft.html
[21] R. Soltek, G. Huttner, WinRay, University of Heidelberg,
Germany, 1999; http://www.chemgeo.uni-hd.de/AC/huttner/
frame/framesoft.html
1470
www.zaac.wiley-vch.de
 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2006, 1465Ϫ1470