Synthesis of new platinum(II) complexes containing hybrid thioether–pyrazole ligands: Structural analysis by 1H and 13C{1H} NMR spectroscopy and X-ray crystal structures

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Inorganica Chimica Acta 360 (2007) 2071–2082

Synthesis of new platinum(II) complexes containing hybridthioether–pyrazole ligands: Structural analysis by 1H and 13C{1H} NMR

spectroscopy and X-ray crystal structures

Antonio de Leon a, Josefina Pons a,*, Jordi Garcıa-Anton a, Xavier Solans b,Merce Font-Bardia b, Josep Ros a,*

a Departament de Quımica, Unitat de Quımica Inorganica, Universitat Autonoma de Barcelona 08193-Bellaterra, Barcelona, Spainb Cristal.lografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Martı i Franques s/n, 08028-Barcelona, Spain

Received 7 September 2006; received in revised form 23 October 2006; accepted 29 October 2006Available online 9 November 2006

Abstract

Treatment of the ligands 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane (bddo), 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianon-ane (bddn), and 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,5-dithiahexane (bddh) with several platinum starting materials as K2PtCl4, PtCl2,[PtCl2(CH3CN)2] and [PtCl2(PhCN)2] was developed under different conditions. The reactions did not yield pure products. The ratioof the NSSN, NS, SS, NN, and 2NS isomers has been calculated through NMR experiments. Treatment of the mixtures of complexeswith NaBPh4 affords [Pt(NSSN)](BPh4)2 (NSSN = bddo, bddn). These Pt(II) complexes have been characterised by elemental analyses,conductivity measurements, IR and 1H and 13C NMR spectroscopy. The X-ray structures of the complexes [Pt(NSSN)](BPh4)2

(NSSN = bddo, bddn) have also been determined. In these complexes, the metal atom is tetracoordinated by the two azine nitrogen atomsof the pyrazole rings and two thioether sulfur atoms. When the [Pt(NSSN)](BPh4)2 (NSSN = bddo, bddn) complexes were heated underreflux in a solution of Et4NBr in CH2Cl2/CH3OH (1:1), a mixture of isomers was obtained.� 2006 Elsevier B.V. All rights reserved.

Keywords: Platinum(II); Hybrids ligands; N ligands; S ligands; Pyrazole complexes; Crystal structures

1. Introduction

The coordination chemistry of the hybrids N,S-donorligands has attracted the attention of several groups [1].These ligands show a remarkable ability to form stableand inert complexes with a wide range of metal ions[1e,1i,1m,1n,2]. The reasons for studying hybrid ligands,in particular hemilabile ligands, derive from their abilityto provide open coordination sites at the metal duringthe reactions. Originally, the interest was centred on revers-ible coordination, stoichiometric, catalytic activation, andtransport of small molecules [1a].

0020-1693/$ - see front matter � 2006 Elsevier B.V. All rights reserved.

doi:10.1016/j.ica.2006.10.035

* Corresponding authors. Tel.: +34 9315818895; fax: +34 93 581 31 01(J. Pons).

E-mail address: [email protected] (J. Pons).

We have reported the reactivity of some previouslydescribed ligands NSN 1,5-bis(3,5-dimethyl-1-pyrazolyl)-3,7-thiapentane (bdtp) [3], and NSSN 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane (bddo) [4], 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) [5], 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,5-dithiahexane (bddh) [6],and 1,7-bis(3,5-dimethyl-1-pyrazolyl)-2,6-dithiaheptane(bddhp) [7] towards Pd(II) [3b,7]. Previously, other authorshave studied the reactivity of the ligands bddo, bddn andbddh with different metals (Cu(II), Ni(II), Co(II), Fe(II),Mn(II), Zn(II) and Cd(II)) [4a–6b,8].

As for most of the 4d metals, the similarity of theirchemistry to that of their 5d congeners (in this case palla-dium to platinum) is well known. We were, therefore, inter-ested in evaluating the behaviour of the aforementionedN,S-donor ligands with Pt(II) in order to compare theresults.

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N N S S N Nx y x

PtClCl

PtClCl

2NS

N N S S N Nx y x

SSPtClCl

N N S S N N

x= 2, y= 2 bddox= 1, y= 2 bddhx= 2, y= 3 bddn

x y x

N N S S N Nx y x

PtClCl

NS

NN

NN Pt

Cl

S S

Cl

NN

x x

y

NN

S

NN

S

Pt

2+

x

y

x

NSSNx=2, y=2 Complex 1

NEt4BrNaBPh4

NSSN, NN y 2NS

NEt4BrNaBPh4

NSSN, NN y 2NS

x=2, y=3 Complex 2

Scheme 1.

2072 A. de Leon et al. / Inorganica Chimica Acta 360 (2007) 2071–2082

Precedents in the literature show that the reactivity ofpyrazolic ligands with Pt(II) yields different results to thoseobtained with Pd(II) [9]. It is also known that palladium ismuch more reactive than platinum.

The reactions of K2PtCl4, PtCl2, [PtCl2(CH3CN)2] and[PtCl2(PhCN)2] with ligands bddo, bddn, and bddh (Scheme1) under various conditions have been tested and describedin this paper. Treatment of the mixtures complexes withNaBPh4 affords [Pt(NSSN)](BPh4)2 (NSSN = bddo (1),bddn (2)). NMR studies and the X-ray crystal structuresof 1 and 2 are also presented.

2. Results and discussion

2.1. Synthesis and spectroscopic properties

The reactions of 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane (bddo) [4], 1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn) [5] and 1,6-bis(3,5-dimethyl-1-pyr-azolyl)-2,5-dithiahexane (bddh) [6] (Scheme 1) with severalplatinum starting materials as K2PtCl4, PtCl2,[PtCl2(CH3CN)2] [10] and [PtCl2(PhCN)2] [11] are devel-oped under different conditions (Scheme 2).

Pd(II) complexes have slightly weaker bonds and react,in general, rather more rapidly than the Pt(II) complexes.They should be otherwise very similar. In our case, and

in contrast to the Pd(II) complexes, Pt(II) reactions takea longer time and need higher temperature to occur [7].

The resulting products of the reactions have been char-acterised by elemental analyses, conductivity measure-ments, and infrared and NMR spectra. The reactions didnot yield pure products. Unfortunately, isolation of the dif-ferent isomers by silica gel chromatography was unsuccess-ful. Recrystallisations of the mixtures with differentsolvents have been carried out but pure products couldnot be obtained.

The elemental analyses and the IR spectra have beenacquired from the pure ones. The ratio of the NSSN, NS,SS, NN, and 2NS has been calculated through NMRexperiments (integration of C–Hpz signals), which were alsouseful to determine the presence of other products.

The different isomers were distinguished using the fol-lowing criteria:

Isomer NSSN: pure NSSN complexes could be obtainedfor bddo (d(C–Hpz) = 5.99 ppm) and bddn (d(C–Hpz) = 6.01 ppm). This isomer was never observed for bddh

complexes.Isomer NN: this isomer was characterised by compari-

son to the [PdCl2(bddo)] [7] complex, which only producesNN isomer. For the NN isomer of [PtCl2(bddo)], d(C–Hpz)is 5.94 ppm. This isomer was never observed for bddn orbddh complexes.

The ratio of the species has been calculated through 1H-RMN experiments, especially from the integration of the pyrazolic proton

bddo + PtCl2CHCl3

2NS (53%) + NSSN (47%)Reflux

bddo + K2PtCl4H2O

25º2NS (52%) + NSSN (48%)

bddo +[PtCl2(CH3CN)2]CH3CN

Reflux

bddo + [PtCl2(PhCN)2] 2NS (54%) + NSSN (46%)CHCl3

Reflux

NS (62%) + NSSN (33%) + NN (5%)

bddn + PtCl2CHCl3

2NS (23%) + NSSN (77%)Reflux

bddn + K2PtCl4H2O

25º2NS (21%) + NSSN (69%) + SS (10%)

bddn +[PtCl2(CH3CN)2]CH3CN

Reflux

bddn + [PtCl2(PhCN)2]CHCl3

Reflux

2NS (27%) + NSSN (58%) + SS (15%)

bddh + PtCl2CHCl3

SS (100%)Reflux

bddh + K2PtCl4H2O

25º2NS (59%) + bddh-H2

2+ (41%)

bddh + [PtCl2(CH3CN)2]CH3CN

Reflux

bddh + [PtCl2(PhCN)2] SS (100%)CHCl3

Reflux

2NS (100%)

Scheme 2.

A. de Leon et al. / Inorganica Chimica Acta 360 (2007) 2071–2082 2073

Isomer NS: two signals can be observed for the C-Hpz ofthe coordinated ligand in this isomer (only observed forbddo). One of them appears at the same position as the freeligand (d(C–Hpz) = 5.79 ppm) and the other one at d(C–Hpz) = 5.87 ppm. Integrations of both peaks are identical.

Isomer SS: This isomer was obtained with bddn andbddh ligands. The reaction of bddh with PtCl2 producesonly the SS isomer. The 1H NMR spectrum of this isomerpresents signals similar to the free ligand for C–Hpz. N–(CH2)x–S chain appears as multiplets due to the effect ofthe coordination to Pt(II).

Isomer 2NS: final isomer determined. d(C–Hpz) appearsat 5.84, 5.86 and 5.85 ppm for bddo, bddn and bddh,respectively.

Elemental analyses are consistent with the mixtureproposed.

The IR spectra of the mixture show bands of the unal-tered ligands [4–6]. When the ligand bddh reacts with

K2PtCl4, a m(N–H) band is observed at 3155–2700 cm�1

and d(N–H) band at 1611 cm�1 [12]. Both bands are attrib-utable to bddh�H2

2þ. Coordination to platinum is dem-onstrated in the IR spectra between 500 and 100 cm�1 ofthe mixture of the compounds. According to IR data forcompounds with bddo, bddn and bddh, the Pt atom is coor-dinated to nitrogen atoms [m(Pt–N) between 556 and376 cm�1], and chlorine atoms [one or two bands of m(Pt–Cl) are observed between 303 and 258 cm�1]. The bandm(Pt–S) is always observed [13].

The 1H NMR, 13C{1H} NMR, HMQC, COSY andNOESY spectra were recorded in CDCl3, except for theligand bddh and K2PtCl4 or [PtCl2(CH3CN)2], which wererecorded in [d6]-dmso. The NMR experiments corroboratethe obtaining of the mixtures and the coordination of theligands around the metallic centre. These ligands can actas tetradentate NSSN, 2NS or bidentate SS, NS or NNchelates depending on the Pt(II) starting materials.


The reaction of bddo with K2PtCl4, PtCl2 and [PtCl2(PhCN)2] leads to obtaining the 2NS (d = 5.84 ppm,CH(pz)) and NSSN (d = 6.01 ppm, CH(pz)) coordination,while for the reaction with [PtCl2(CH3CN)2], the NS (d =5.79, 5.87 ppm, CH(pz)), NN (d = 5.94 ppm, CH(pz)),and NSSN (d = 6.02 ppm, CH(pz)) coordination modeshave been obtained (Fig. 1). On the other hand, the reac-tion of bddn with K2PtCl4 and [PtCl2(CH3CN)2] gives2NS (d = 5.88 ppm, CH(pz)), SS (d = 5.85 ppm, CH(pz))and NSSN (d = 6.02 ppm, CH(pz)) coordination modes,while in the reaction with PtCl2, 2NS (d = 5.88 ppm,CH(pz)), and NSSN (d = 6.02 ppm, CH(pz)) coordinationmodes are obtained.

In contrast, when the ligand bddh reacts with PtCl2 and[PtCl2(PhCN)2], the SS (d = 5.90 ppm, CH(pz)) isomer isformed. The reaction with [PtCl2(CH3CN)2] leads to theobtaining of the 2NS (d = 5.85 ppm, CH(pz)) isomer. Thecoordination mode 2NS (d = 5.85 ppm, CH(pz)) and theprotonated ligand bddh�H2

2þ (d = 6.14 ppm, CH(pz))have been obtained when the ligand bddh reacts withK2PtCl4. Moreover, the 1H NMR spectrum presents abroad band at 8.50 ppm, which corresponds to NH(pz) [6].

The formation of the complexes in which the Pt(II) cen-tre is bonded to two pyrazole rings and two sulfur atoms isfavourable for bddo and bddn ligands, while these kinds ofcomplexes were not obtained with the bddh ligand, proba-bly because of the imposed geometry of the hypotheticalPtNNCS metallocycle, which would induce steric hin-drance between the methyl groups of the pyrazole rings.These results are in agreement with the experimental dataobtained with Pd(II) and the same ligands [7] and the the-oretical study, which analyzes the influence of the numberof –CH2– groups that join the two pyrazole rings, the nat-

Fig. 1. The 250 MHz 1H NMR spectru

ure of donor atoms directly bonded to the metal centre inthe products, and the electronic effects induced by subsis-tent groups of the pyrazole rings [14].

In order to be able to isolate one of the isomers (NSSN)from the mixtures, treatment of bddo and bddn mixtureswith NaBPh4 was carried out. These reactions gave com-pounds of formula [Pt(NSSN)](BPh4)2 (NSSN = bddo(1), bddn (2)) as pure products (NSSN isomer). In contrast,use of the same reaction conditions with the mixture ofcomplexes with the ligand bddh gave decomposition prod-ucts. When complexes 1 and 2 were heated under reflux in asolution of Et4NBr in CH2Cl2/CH3OH (1:1) for 24 h, mix-tures of complexes were again obtained (2NS(28%) + NSSN (35%) + NN (37%) for 1 and 2NS(10%) + NSSN (54%) + NN (36%) for 2). This proves thetype 3 hemilability of ligands bddo and bddn towards Pt(II)[1a].

The elemental analyses of products 1 and 2 are consis-tent with the formula [Pt(NSSN)](BPh4)2. The positiveionisation spectra of 1 and 2 gave peaks with m/z valueof 266 [Pt(bddo)]2+ and 273 [Pt(bddn)]2+, respectively(molecular peak of the cation). Conductivity values inDMF for complexes 1 and 2 are in agreement with 2:1 elec-trolytes. The reported values for 10�3 M solutions of 1:2electrolyte compounds in DMF are between 130 and170 X�1 cm2 mol�1 [15]. The IR spectra of complexes 1

and 2 are similar to those of the ligands, the most charac-teristic bands being those attributable to the pyrazolylgroup: m(C@C) m(C@N)ar, between 1579–1572 cm�1 andd(C–H)oop between 850–799 cm�1. The m(B–C) band at727 and 721 cm�1 is characteristic for 1 and 2, respectively[12b]. For complexes 1 and 2, the m(Pt–N) and m(Pt–S)bands can be attributed to the signal appearing between

m of a mixture of bddo + K2PtCl4.

Table 11H NMR results: chemical shifts (ppm) and 1H, 1H coupling constants(Hz) for 1 and 2 in [d6]-acetone

Compound 1 2

d 6R–H 5.07 5.26d 6S–H 4.72 4.88d 7R–H 3.55 3.69d 7S–H 3.38 3.28d 8R–H 2.68 3.28d 8S–H 3.41 3.28d 9–H 2.352J(6R–H, 6S–H) 15.22 15.602J(7R–H, 7S–H) 13.79 13.823J(6R–H, 7R–H) 11.91 11.193J(6S–H, 7S–H) 1.92 2.093J(6R–H, 7S–H) 2.96 2.963J(6S–H, 7R–H) 3.74 3.852J(8R–H, 8S–H) 8.04 n.d.


484–464 and 326–306 cm�1, respectively [13]. The 1HNMR, 13C{1H} NMR, HMQC, and NOESY spectra wererecorded in [d6]-acetone.

The 1H and 13C{1H} NMR spectra of complexes 1 and 2

show the signals of coordinated ligands. NMR spectro-scopic data are shown in Section 4. NMR spectra of com-pounds 1 and 2 were studied in more detail.

The two different chains [S–(CH2)2–N and S–(CH2)x–S;x = 2 for 1 and x = 3 for 2] were studied separately.HMQC spectra were used to assign the signals of protons6-H, 7-H and 8-H for 1 (Fig. 2) and 6-H, 7-H, 8-H and9-H for 2. Simulated 1H NMR spectra of both chains wereobtained by use of the g NMR program [16]. The couplingconstants are reported in Table 1.

Due to the symmetry of 1, the two CH2 units in the S–CH2CH2–S fragment are equivalent. Moreover, the twoprotons of each CH2 are diastereotopic and can be assignedto the two doublets found at d = 3.41 and 2.68 ppm(2J = 8.0 Hz).

The signal of H8 for the S–(CH2)3–S chain in compound2 is superposed on that of H7 and could not be furtherstudied.

For complexes 1 and 2, the two protons of each CH2

group in the S–CH2–CH2–N chain are diastereotopic, thusgiving rise to four groups of signals, each attributable to asingle hydrogen atom. This happens because of the rigidconformation of the ligand when it is complexed. In thisway, each group of signals can be assigned as a double dou-ble doublet. Fig. 3 shows the experimental and simulatedspectra for 1.

Study of the S–CH2–CH2–N fragment (for 1 and 2) asan AA 0XX 0 system gave a set of coupling constants (Table

Fig. 2. The 250-MHz 2D HMQC spectrum of [

1) for each complex. These constants were consistent withthe simulated spectra obtained with the aid of the g NMR

program [16].In the NOESY spectra, the methyl(pyrazole) groups at

d = 2.40 (1) and d = 2.44 (2) ppm show NOE interactionwith the double double doublet at d = 4.72 (1) and 4.81(2) ppm, but not with the ones at d = 5.07 (1) and 5.26(2) ppm. This allowed us to assign 6 S–H to the first setof double double doublets at d = 4.72 (1) and 4.88 (2)ppm, and 6R-H to the signals at d = 5.07 (1) and 5.26 (2)ppm. This assignation could be done thanks to the X-raystructure of 1 and 2 (Figs. 4 and 5, respectively), where itcan be seen that the shortest distance (2.026 and 2.065 A

Pt(bddo)](BPh4)2 Æ 2CH3COCH3 Æ 2H2O (1).

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 2.400 2.200

Experimental

Simulated

6R-H 7R-H 6S-H 7S-H

8 S-H

8 R-H

5

24

H7S

H6S

H7R

H6R

NN

S

NN

S

Pt

2+H8R H8S

Fig. 3. The 250-MHz 1H NMR and the simulated g NMR spectra for the 6-H, 7-H, 8-H protons of the S-CH2–CH2–N fragment of[Pt(bddo)](BPh4)2 Æ 2CH3COCH3 Æ 2H2O (1).

Fig. 4. ORTEP drawing of [Pt(bddo)](BPh4)2 Æ 2CH3COCH3 Æ 2H2O (1),showing all non-hydrogen atoms and the atom-numbering scheme; 50%probability amplitude displacement ellipsoids are shown.

Fig. 5. ORTEP drawing of [Pt(bddn)](BPh4)2 (2), showing all non-hydrogenatoms and the atom-numbering scheme; 50% probability amplitudedisplacement ellipsoids are shown.


for 1 and 2, respectively) was found between 6S–H and themethyl(pyrazole) groups at 2.40 (1) and 2.44 (2) ppm.

The coupling constants enabled us to differentiate 7S–Hand 7R–H. These coupling constants agree with the confor-mation of the S–CH2–CH2–N chain as seen in Figs. 4 and5.

Additional 195Pt{1H} NMR experiments for complexes1 and 2 at 298 K revealed only one band for each complex(d = �3884 ppm for 1 and �3883 ppm for 2). The195Pt{1H} chemical shifts are downfield compared to othercomplexes with core-PtN2S2 (�3261, �3313 ppm) [17] andcore-PtNSCl2 (�2868, �2879 ppm) [18], whereas the chem-

ical shifts are highfield compared with core-PtP2S2

(�4347, �4452 ppm) [19] and core-PtS4 (�4117 ppm) [20],illustrating how the platinum chemical shift is sensitive tothe average ligand environment.

2.2. Crystal structure of [Pt(bddo)](BPh4)2 Æ2CH3COCH3 Æ 2H2O (1) and [Pt(bddn)](BPh4)2 (2)

Structures 1 and 2 (Figs. 4 and 5, respectively) consist ofcationic units [Pt(bddo)]2+ (1) and [Pt(bddn)]2+ (2), BPh4

�

anions, and, in structure 1 solvent molecules (twoCH3COCH3, and two H2O).

Table 2Selected bond lengths (A) and bond angles (�) for [Pt(bddo)](BPh4)2 (1)and [Pt(bddn)] (BPh4)2 (2)

1 2

Pt–N(2)# 2.0776(19) Pt–N(4) 2.041(5)Pt–N(2) 2.0776(19) Pt–N(1) 2.056(4)Pt–S#1 2.2586(9) Pt–S(2) 2.2717(16)Pt–S 2.2586(9) Pt–S(1) 2.2775(16)

N(2)#1–Pt–N(2) 94.11(11) N(4)–Pt–N(1) 89.75(19)N(2)#1–Pt–S#1 88.03(7) N(4)–Pt–S(2) 89.64(16)N(2)–Pt–S#1 177.24(6) N(1)–Pt–S(2) 178.16(13)N(2)#1–Pt–S 177.24(6) N(4)–Pt–S(1) 178.95(17)N(2)–Pt–S 88.03(7) N(1)–Pt–S(1) 89.46(12)S#1–Pt–S 89.88(5) S(2)–Pt–S(1) 91.17(6)


Two nitrogen atoms of the pyrazolyl groups and twothioether groups coordinate the platinum atom in asquare-planar geometry. The pyrazolyl groups are in cis

disposition. For compounds 1 and 2, the tetrahedral distor-tion of the square-planar geometry can be observed in themean separation of the atoms linked to platinum from themean plane, which is 0.034(2) A and 0.024(5) A, respec-tively. The dihedral angle between the planes N(2)#1–Pt–N(2) and S#1–Pt–S is 2.48(6)� (for 1), and between theplanes N(1)–Pt–N(4) and S(1)–Pt–S(2) is 1.85(12)� (for 2).Some selected bond lengths and bond angles for these com-plexes are listed in Table 2.

No PtN2S2 core (N pyrazole and S thioether) with crys-tal structure was found in the literature, whereas nine struc-tures with PtN2S2 core (N aromatic and S thioether) havebeen described [21]. For complexes 1 and 2, the Pt–N[9b,17,18,22] and Pt–S [18,21] bond lengths are of the sameorder as those found in the literature. Ligands bddo andbddn act as tetradentate chelates. The ligand bddo formstwo Pt–N–N–C–C–S six-membered rings and one Pt–S–C–C–S five-membered ring. All of them have boat confor-mation. Bddn forms three six-membered rings, two Pt–N–N–C–C–S and one Pt–S–C–C–C–S, all of which also haveboat conformation. Bite angles are 88.03(7)�, 88.03(7)� and89.88(5)� for N(2)#1–Pt–S#1, N(2)–Pt–S, and S#1–Pt–S,respectively, in 1 and 89.64(16)�, 89.46(12)�, and 91.17(6)�for N(4)–Pt–S(2), N(1)–Pt–S(1), and S(2)–Pt–S(1), respec-tively, in 2. For complexes 1 and 2, these bite angles aresimilar to those reported for [Pd(bddo)](BF4)2 Æ H2O,88.2(2)�, and 86.2(1)� [7], [Pd(bddn)](BF4)2, 86.81(12)�,and 85.81(11)� [23], and [PtCl2(thpd)] [thpd = 1-(3-thia-5-hydroxypentyl)-3,5-dimethylpyrazole], 87.5(3)� [18].

3. Conclusion

The reaction of bddo, bddn and bddh with different Pt(II)starting materials yields different mixtures of the NN, NS,SS, 2NS, and NSSN isomers. This behaviour is completelydifferent from the results obtained for the reaction with thesame ligands and Pd(II), where only the NN isomer wasobtained [7]. We have observed higher affinity of Pt(II) tothe thioether moieties than Pd(II), as more isomers con-

taining M–S bonds have been obtained with Pt(II) thanPd(II).

In order to isolate the NSSN isomer, we performed thereaction of the bddo and bddn mixture of isomers withNaBPh4, obtaining [Pt(bddo)](BPh4)2 and [Pt(bddn)](BPh4)2, respectively, as pure products. In this case, theonly coordination observed is NSSN.

When these two products are refluxed in CH2Cl2/CH3OH in the presence of Et4NBr, a new mixture of2NS, NSSN and NN isomers is obtained. This proves thehemilability of these ligands towards Pt(II) [1a].

For bddh mixture of isomers, the reaction with NaBPh4

yields decomposition of products, as observed for[PdCl2(bddh)] [7,14].

4. Experimental

4.1. General details

The reactions were carried out under nitrogen atmo-sphere using vacuum line and Schlenk techniques. The sol-vents were dried and distilled according to standardprocedures and stored under nitrogen. Elemental analyses(C, H, N, S) were carried out by the staff of Chemical Anal-yses Service of the Universitat Autonoma de Barcelona ona Carlo Erba CHNS EA-1108 instrument. Conductivitymeasurements were performed at room temperature (r.t.)in 10�3 M DMF solutions, employing a CyberScan CON500 (Euthech instrument) conductimeter. Infrared spectrawere run on a Perkin–Elmer FT spectrophotometer, series2000 cm�1 as KBr pellets or polyethylene films in the range4000–100 cm�1. 1H NMR, 13C {1H} NMR, HMQC,COSY and NOESY spectra were recorded on a NMR-FT Bruker AC-250 MHz spectrometer in CDCl3, CD2Cl2[d6]-acetone or [d6]-dmso solutions at room temperature.195Pt{1H} NMR spectra were recorded at 25 �C and77.42 MHz on a DPX-360 Bruker spectrometer using aque-ous solutions of [PtCl6]2� (0 ppm) as an external referenceand delay time 0.01 s. All chemical shifts values (d) aregiven in ppm. Mass spectra were obtained with an Esquire3000 ion trap mass spectrometer from Bruker Daltonics.

Samples of [PtCl2(CH3CN)2] [10] and [PtCl2(PhCN)2][11] were prepared as described in the literature. 1,8-bis(3,5-dimethyl-1-pyrazolyl)-3,6-dithiaoctane (bddo) [4],1,9-bis(3,5-dimethyl-1-pyrazolyl)-3,7-dithianonane (bddn)[5], and 1,6-bis(3,5-dimethyl-1-pyrazolyl)-2,5-dithiahexane(bddh) [6] were prepared according to the published meth-ods (Scheme 1).

4.2. Reactions of bddo, bddn and bddh with K2PtCl4 in H2O

To a solution of 0.24 mmol (0.10 g) of K2PtCl4 in 10 mlof water, 0.24 mmol of the corresponding ligand (0.080 g ofbddo, 0.087 g of bddn or 0.075 g of bddh) dissolved in 10 mlof water was added. The solution was stirred at room tem-perature for 24 h (until the red colour of the starting mate-rial K2PtCl4 had completely disappeared), and an orange


solid precipitated. It was filtered off, washed twice with5 ml of cold water and dried in vacuum.

4.3. Reactions of bddo, bddn and bddh with PtCl2

Chloroform (15 ml) was quickly added to 0.27 mmol(0.072 g) of PtCl2 and 0.27 mmol of the correspondingligand (0.090 g of bddo, 0.096 g of bddn or 0.086 g of bddh)dissolved in 15 ml of the same solvent. The mixture wasrefluxed for 48 h. The yellowish solution was filtered to sep-arate Pt(0) and the starting material PtCl2. The solvent wasevaporated to dryness leaving a yellow solid, which was fil-tered off, washed with 10 ml of CH2Cl2/diethyl ether (1:1)and dried in vacuum.

4.4. Reactions of bddo, bddn and bddh with

[PtCl2(CH3CN)2]

To a solution of 0.23 mmol (0.080 g) of[PtCl2(CH3CN)2] in 15 ml of acetonitrile, 0.23 mmol ofthe corresponding ligand (0.077 g of bddo, 0.083 g of bddn

or 0.071 g of bddh) dissolved in 15 ml of acetonitrile wasadded. The solution was refluxed for 24 h. The solventwas evaporated to dryness leaving an orange solid, whichwas filtered off, washed with 10 ml of CH2Cl2/diethyl ether(1:1) and dried in vacuum.

4.5. Reaction of bddo, bddn and bddh with [PtCl2(PhCN)2]

To a solution of 0.21 mmol (0.10 g) of [PtCl2(PhCN)2] in15 ml of chloroform, 0.21 mmol of the correspondingligand (0.072 g of bddo or 0.065 g of bddh) dissolved in15 ml of the same solvent was added. The mixture wasrefluxed for 24 h. The yellow solution was evaporated todryness. The ligand bddn with [PtCl2(PhCN)2] did not reactthrough this method; the platinum starting material andthe free ligand were recovered unaltered.

4.5.1. bddoK2PtCl4. (Yield: 64%) (52% C1 + 48% C2)

(C1 = Pt2Cl4(bddo); C2 = PtCl2(bddo)): Anal. Calc. forK2PtCl4: C, 25.87; H, 3.53; N, 7.54; S, 8.63. Found: C,25.86; H, 3.51; N, 7.48; S, 8.59%. Conductivity(X�1 cm2 mol�1, 1.02 · 10�3 M in DMF): 109. IR (KBr,cm�1): 3114 m(C–H)ar, 2967, 2915 m(C–H)al, 1554(m(C@C), m(C@N))ar, 1465, 1417 (d(C@C), d(C@N))ar,1067, 1027 d(C–H)ip, 798 d(C–H)oop. (Polyethylene,cm�1): 440 m(Pt–N), 317, 311 m(Pt–S), 272, 262 m(Pt–Cl).1H NMR (CDCl3 solution, 250 MHz) d: 2NS: 5.86 [2 H,s, CH(pz)], 4.41 [2H, m, NpzCH2CH2S], 3.48/2.83 [2H/2H, m, NpzCH2CH2S], 3.01 [4H, m, SCH2CH2S], 2.40[6H, s, CH3(pz)], 2.37 [6H, s, CH3(pz)] ppm. NSSN: 6.02[1.87H, s, CH(pz)], 5.74/5.10 [1.87H/1.87H, m,NpzCH2CH2S], 4.50 [4H, m, SCH2CH2S], 3.83, 3.60[1.87H/1.87H, m, NpzCH2CH2S], 2.52 [5.63H, s, CH3(pz)],2.20 [5.63H, s, CH3(pz)] ppm. 13C{1H} NMR (CD3Cl solu-tion, 63 MHz,) d: 2NS + NSSN: 151.9–147.6 (pz-C),

143.6–140.6 (pz-C), 108.0, 106.0 (CH(pz)), 61.0–45.8(NpzCH2CH2S), 40.2–35.6 (NpzCH2CH2S, SCH2CH2S),14.1–11.0 (CH3(pz)) ppm.

4.5.2. PtCl2(Yield: 66%) (53% C1 + 47% C2) (C1 = Pt2Cl4(bddo);

C2 = PtCl2(bddo)): Anal. Calc. for PtCl2: C, 25.77; H,3.51; N, 7.51; S, 8.60. Found: C, 25.38; H, 3.61; N, 7.06;S, 8.64%. Conductivity (X�1 cm2 mol�1, 1.13 · 10�3 M inDMF): 41. IR (KBr, cm�1): 3114 m(C–H)ar, 2963, 2918m(C–H)al, 1553 (m(C@C), m(C@N))ar, 1465, 1421 (d(C@C),d(C@N))ar, 1097, 1024 d(C–H)ip, 800 d(C–H)oop. (Polyeth-ylene, cm�1): 405, 391, 376 m(Pt–N), 317, 308 m(Pt–S), 275,260 m(Pt–Cl). 1H NMR (CDCl3 solution, 250 MHz) d:2NS: 5.84 [2H, s, CH(pz)], 4.40 [2H, m, NpzCH2CH2S],3.43/2.77 [2H/2H, m, NpzCH2CH2S], 3.07 [4H, m,SCH2CH2S], 2.40 [6H, s, CH3(pz)], 2.37 [6H, s, CH3(pz)]ppm. NSSN: 6.02 [1.75H, s, CH(pz)], 5.74/5.10 [1.75H/1.75H, m, NpzCH2CH2S], 4.61 [4H, m, SCH2CH2S], 3.82/3.57 [1.75H/1.75H, m, NpzCH2CH2S], 2.52 [5.24H, s,CH3(pz)], 2.18 [5.24H, s, CH3(pz)] ppm. 13C{1H} NMR(CD3Cl solution, 63 MHz,) d: 2 NS + NSSN: 152.0–147.9(pz-C), 143.6–140.4 (pz-C), 108.0, 106.0 (CH(pz)), 61.1–45.8 (NpzCH2CH2S), 41.9–35.0 (NpzCH2CH2S,SCH2CH2S), 14.1–11.0 (CH3(pz)) ppm.

4.5.3. [PtCl2(CH3CN)2]

(Yield: 53%) (100% C2) (C2 = PtCl2(bddo)): Anal. Calc.for [PtCl2(CH3CN)2]: C, 31.79; H, 4.33; N, 9.27; S, 10.61.Found: C, 31.76; H, 4.30; N, 9.27; S, 10.58%. Conductivity(X�1 cm2 mol�1, 0.96 · 10�3 M in DMF): 31. IR (KBr,cm�1): 3182 m(C–H)ar, 2967, 2928 m(C–H)al, 1552(m(C@C), m(C@N))ar, 1461, 1420 (d(C@C), d(C@N))ar,1033 d(C–H)ip, 790 d(C–H)oop. (Polyethylene, cm�1): 444m(Pt–N), 319, 308 m(Pt–S), 270, 261 m(Pt–Cl). 1H NMR(CDCl3 solution, 250 MHz) d: NS: 5.87/5.79 [1H/1H, s,CH(pz)], 4.39 [1H, m, NpzCH2CH2S], 4.14 [2H, t,NpzCH2CH2S], 3.49/2.03 [1H/1H, m, NpzCH2CH2S], 2.94[2H, t, NpzCH2CH2S], 2.51 [4H, s, SCH2CH2S], 2.39/2.26[3H/3H, s, CH3(pz)], 2.38/2.21 [3H/3H, s, CH3(pz)] ppm.NSSN: 6.02 [1.06H, s, CH(pz)], 5.70/4.98 [1.07H/1.07H,m, NpzCH2CH2S], 4.49 [2.13H, m, SCH2CH2S], 3.86/3.64[1.07H/1.07H, m, NpzCH2CH2S], 2.52 [3.19H, s, CH3(pz)],2.19 [3.19H, s, CH3(pz)] ppm. NN: 5.94 [0.16H, s, CH(pz)]ppm. 13C{1H} NMR (CD3Cl solution, 63 MHz,) d:NS + NSSN + NN: 152.6–148.0 (pz-C), 143.9–140.7 (pz-C), 108.7, 106.6, 105.4 (CH(pz)), 61.7–46.6(NpzCH2CH2S), 42.1–32.4 (NpzCH2CH2S, SCH2CH2S),14.7–11.5 (CH3(pz)) ppm.

4.5.4. [PtCl2(PhCN)2]

(Yield: 58%) (54% C1 + 46% C2) (C1 = Pt2Cl4(bddo);C2 = PtCl2(bddo)): Anal. Calc. for [PtCl2(PhCN)2]: C,25.73; H, 3.51; N, 7.50; S, 8.59. Found: C, 25.70; H, 3.89;N, 7.48; S, 8.63%. Conductivity (X�1 cm2 mol�1,1.23 · 10�3 M in DMF): 48. IR (KBr, cm�1): 3113 m(C–H)ar, 2964, 2923 m(C–H)al, 1553 (m(C@C), m(C@N))ar,


1462, 1421 (d(C@C), d(C@N))ar, 1098, 1024 d(C–H)ip, 801d(C–H)oop. (Polyethylene, cm�1): 465, 445 m(Pt–N), 319,308 m(Pt–S), 272, 258 m(Pt–Cl). 1H NMR (CDCl3 solution,250 MHz) d: 2NS: 5.84 [2H, s, CH(pz)], 4.40 [2H, m,NpzCH2CH2S], 3.46/2.78 [2H/2H, m, NpzCH2CH2S], 3.07[4H, m, SCH2CH2S], 2.39 [6H, s, CH3(pz)], 2.37 [6H, s,CH3(pz)] ppm. NSSN: 6.01 [1.71H, s, CH(pz)], 5.72/5.07[1.71H/1.71H, m, NpzCH2CH2S], 4.48 [3.42H, m,SCH2CH2S], 3.85/3.63 [1.71H/1.71H, m, NpzCH2CH2S],2.52 [5.13H, s, CH3(pz)], 2.19 [5.13H, s, CH3(pz)] ppm.13C{1H} NMR (CD3Cl solution, 63 MHz,) d: 2

NS + NSSN: 152.0–147.9 (pz-C), 143.3–140.2 (pz-C),108.1, 106.0, (CH(pz)), 61.1–46.0 (NpzCH2CH2S), 41.6–31.8 (NpzCH2CH2S, SCH2CH2S), 14.1–11.9 (CH3(pz))ppm.

4.5.5. bddnK2PtCl4. (Yield: 67%) (21% C1 + 79% C2) (C1 = Pt2Cl4

(bddn); C2 = PtCl2): Anal. Calc. for bddn. K2PtCl4: C,30.28; H, 4.18; N, 8.31; S, 9.51. Found: C, 30.05; H, 4.15;N, 8.24; S, 9.43%. Conductivity (X�1 cm2 mol�1,0.84 · 10�3 M in DMF): 122. IR (KBr, cm�1): 3136 m(C–H)ar, 2967, 2924 m(C–H)al, 1551 (m(C@C), m(C@N))ar,1471, 1422 (d(C@C), d(C@N))ar, 1069, 1038 d(C–H)ip,805 d(C–H)oop. (Polyethylene, cm�1): 441 m(Pt–N), 321m(Pt–S), 271 m(Pt–Cl). 1H NMR (CDCl3 solution,250 MHz) d: 2NS: 5.88 [0.62H, s, CH(pz)], 4.49/4.35[0.62H/0.62H, m, NpzCH2CH2S], 2.78 [0.62H, m,NpzCH2CH2S], 3.74 [1.25H, t, SCH2CH2CH2S], 1.85[0.62H, m, SCH2CH2CH2S], 2.40 [1.37H, s, CH3(pz)],2.37 [1.37H, s, CH3(pz)] ppm. NSSN: 6.02 [2H, s, CH(pz)],4.89 [2H, m, NpzCH2CH2S], 4.62 [6H, m, SCH2CH2CH2S],2.52 [6H, s, CH3(pz)], 2.24 [6H, s, CH3(pz)] ppm. SS: 5.85[0.28H, s, CH(pz)], 4.62 [0.84H, m, SCH2CH2CH2S], 4.22[0.56H, t, NpzCH2CH2S], 2.96 [0.56H, t, NpzCH2CH2S],2.30 [0.84H, s, CH3(pz)], 2.27 [0.84H, s, CH3(pz)] ppm.13C{1H} NMR (CD2Cl2 solution, 63 MHz,) d: 2

NS + NSSN + SS: 108.4, 108.1, 105.9, 105.1 (CH(pz)),49.8, 48.4, 48.3 (NpzCH2CH2S), 31.8–31.1 (NpzCH2CH2S,SCH2CH2CH2S), 29.8–28.2 (SCH2CH2CH2S), 15.0–11.0(CH3(pz)) ppm.

4.5.6. PtCl2(Yield: 30%) (23% C1 + 77% C2) (C1 = Pt2Cl4(bddn);

C2 = PtCl2(bddn)): Anal. Calc. for PtCl2: C, 30.04; H,4.15; N, 8.24; S, 9.43. Found: C, 29.71; H, 3.55; N, 8.19;S, 9.00%. Conductivity (X �1 cm2 mol�1, 1.01 · 10�3 M inDMF): 41. IR (KBr, cm�1): 3136 m(C–H)ar, 2952, 2920m(C–H)al, 1553 (m(C@C), m(C@N))ar, 1465, 1421 (d(C@C),d(C@N))ar, 1096, 1031 d(C–H)ip, 801, 752 d(C–H)oop.(Polyethylene, cm�1): 453 m(Pt–N), 327 m(Pt–S), 279 m(Pt–Cl). 1H NMR (CDCl3 solution, 250 MHz) d: 2NS: 5.88[0.59H, s, CH(pz)], 2.78 [0.59H, m, NpzCH2CH2S], 3.75[1.17H, t, SCH2CH2CH2S], 1.85 [0.59H, m, SCH2

CH2CH2S], 2.42 [1.76H, s, CH3(pz)], 2.39 [1.76H, s,CH3(pz)] ppm. NSSN: 6.02 [2H, s, CH(pz)], 5.94 [2H, m,NpzCH2CH2S], 4.62 [6H, m, SCH2CH2CH2S], 3.85/3.63

[1.71H/1.71H, m, NpzCH2CH2S], 2.57 [6H, s, CH3(pz)],2.24 [6H, s, CH3(pz)] ppm. 13C{1H} NMR (CD2Cl2 solu-tion, 63 MHz,) d: 2 NS + NSSN: 109.9, 107.5, 106.8(CH(pz)), 50.0, 49.9 (NpzCH2CH2S), 33.4–31.1(NpzCH2CH2S, SCH2CH2CH2S), 14.3–12.6 (CH3(pz))ppm.

4.5.7. [PtCl2(CH3CN)2]

(Yield: 35%) (27% C1 + 73% C2) (C1 = Pt2Cl4(bddn);C2 = PtCl2(bddn)): Anal. Calc. for [PtCl2(CH3CN)2]: C,29.57; H, 4.08; N, 8.11; S, 9.29. Found: C, 29.23; H, 4.07;N, 8.06; S, 8.98%. Conductivity (X�1 cm2 mol�1,1.15 · 10�3 M in DMF): 35. IR (KBr, cm�1): 3136 m(C–H)ar, 2952, 2919 m(C–H)al, 1553 (m(C@C), m(C@N))ar,1468, 1420 (d(C@C), d(C@N))ar, 1034 d(C–H)ip, 801 d(C–H)oop. (Polyethylene, cm�1): 452 m(Pt–N), 324 m(Pt–S),279 m(Pt–Cl). 1H NMR (CDCl3 solution, 250 MHz) d:2NS: 5.86 [0.94H, s, CH(pz)], 4.42/4.27 [0.94H/0.94H, m,NpzCH2CH2S], 3.48/2.99 [0.94/0.94H, m, NpzCH2CH2S],3.13 [1.88H, t, SCH2CH2CH2S], 1.77 [0.94H, m,SCH2CH2CH2S], 2.40 [1.50H, s, CH3(pz)], 2.35 [1.50H, s,CH3(pz)] ppm. NSSN: 6.02 [2H, s, CH(pz)], 6.24/4.88[2H/2H, m, NpzCH2CH2S], 4.70 [6H, m, SCH2CH2CH2S],2.53 [6H, s, CH3(pz)], 2.21 [6H, s, CH3(pz)] ppm. SS: 5.81[0.50H, s, CH(pz)], 4.70 [1.50H, m, SCH2CH2CH2S], 4.16[1H, t, NpzCH2CH2S], 2.92 [1H, t, NpzCH2CH2S], 2.27[1.50H, s, CH3(pz)], 2.23 [1.50H, s, CH3(pz)] ppm.13C{1H} NMR (CDCl3 solution, 63 MHz,) d: 2

NS + NSSN + SS: 144.0–141.7 (pz-C), 108.5, 108.1,106.3, 105.5 (CH(pz)), 52.3, 49.1, 48.6 (NpzCH2CH2S),37.6–30.6 (NpzCH2CH2S, SCH2CH2CH2S), 30.2–28.2(SCH2CH2CH2S), 15.4, 12.7, 12.3, 11.4 (CH3(pz)) ppm.

4.5.8. bddhK2PtCl4. (Yield: 58%) ð59% C1 þ 41% bddh�H2

2þÞ(C1 = Pt2Cl4(bddh)). Conductivity (X �1 cm2 mol�1,1.22 · 10�3 M in DMF): 93. IR (KBr, cm�1): 3115–2770m(N–H), 3136 m(C–H)ar, 2967, 2919 m(C–H)al, 1611 d(N–H), 1560 (m(C@C), m(C@N))ar, 1464, 1417 (d(C@C),d(C@N))ar, 1067, 1030 d(C–H)ip, 805 d(C–H)oop. (Polyeth-ylene, cm�1): 556, 502, 473 m(Pt–N), 302 m(Pt–S), 279 m(Pt–Cl). 1H NMR ([d6]-dmso solution, 250 MHz) d: 2NS: 5.85[1.40H, s, CH(pz)], 5.96 [2.80H, m, NpzCH2S], 2.78 [2.70H,s, SCH2CH2S], 2.24 [4.20H, s, CH3(pz)], 2.09 [4.20H, s,CH3(pz)] ppm. Bddh�H2

2þ: 8.50 [1H, br, NH], 6.14[2H, s, CH(pz)], 5.23 [4H, s, NpzCH2S], 2.25 [6H, s,CH3(pz)], 2.24 [6H, s, CH3(pz)] ppm. 13C{1H} NMR([d6]-dmso solution, 63 MHz,) d 2NS þ Bddh�H2

2þ:145.7, 144.5, 142.4 (pz-C), 140.2, 139.0 (pz-C), 106.0,105.6 (CH(pz)), 48.9 (NpzCH2S), 34.0, 30.5 (SCH2CH2S),13.3–10.3 (CH3(pz)) ppm.

4.5.9. PtCl2(Yield: 23%) (100% C2) (C2 = PtCl2(bddh)): Anal. Calc.

for PtCl2: C, 29.17; H, 3.85; N, 9.72; S, 11.12. Found: C,29.03; H, 3.82; N, 9.90; S, 11.09%. Conductivity(X�1 cm2 mol�1, 0.95 · 10�3 M in DMF): 12. IR (KBr,


cm�1): 3133 m(C–H)ar, 2963, 2921 m(C–H)al, 1563 (m(C@C),m(C@N))ar, 1463, 1398 (d(C@C), d(C@N))ar, 1093, 1031d(C–H)ip, 803 d(C–H)oop. (Polyethylene, cm�1): 322 m(Pt–S), 298 m(Pt–Cl). 1H NMR (CDCl3 solution, 250 MHz)d:SS: 5.90 [2H, s, CH(pz)], 5.80 [4H, s, NpzCH2S], 2.70[4H, m, SCH2CH2S], 2.34 [6H, s, CH3(pz)], 2.23 [6H, s,CH3(pz)] ppm. 13C{1H} NMR (CDCl3 solution,63 MHz,) d SS: 147.2–144.9 (pz-C), 140.8–140.0 (pz-C),107.5 (CH(pz)), 59.5 (NpzCH2S), 21.9 (SCH2CH2S), 13.2–10.7 (CH3(pz)) ppm.

4.5.10. [PtCl2(CH3CN)2]

(Yield: 15%) (100% C1) (C1 = Pt2Cl4(bddh)): Anal. Calc.for [PtCl2(CH3CN)2]: C, 19.96; H, 2.63; N, 6.65; S, 7.61.Found: C, 20.07; H, 2.45; N, 6.40; S, 8.03%. Conductivity(X�1 cm2 mol�1, 0.98 · 10�3 M in DMF): 27. IR (KBr,cm�1): 3182 m(C–H)ar, 2967, 2928 m(C–H)al, 1552(m(C@C), m(C@N))ar, 1461, 1420 (d(C@C), d(C@N))ar,1033 d(C–H)ip, 790 d(C–H)oop. (Polyethylene, cm�1): 556,502, 470 m(Pt–N), 323 m(Pt–S), 302, 289 m(Pt–Cl). 1HNMR ([d6]-dmso solution, 250 MHz) d: 2NS: 5.85 [2H, s,CH(pz)], 5.98 [4H, s, NpzCH2S], 2.77 [4H, s, SCH2CH2S],2.22 [6H, s, CH3(pz)], 2.15 [6H, s, CH3(pz)] ppm.13C{1H} NMR ([d6]-dmso solution, 63 MHz,) d 2NS:147.1–145.7 (pz-C), 140.1–139.1 (pz-C), 106.1 (CH(pz)),49.0 (NpzCH2S), 34.1 (SCH2CH2S), 12.6–10.6 (CH3(pz))ppm.

4.5.11. [PtCl2(PhCN)2]

(Yield: 17%) (100% C2) (C2 = PtCl2(bddh)): Anal. Calc.for [PtCl2(PhCN)2]: C, 29.17; H, 3.85; N, 9.72; S, 11.12.Found: C, 29.25; H, 4.02; N, 9.70; S, 11.07%. Conductivity(X�1 cm2 mol�1, 0.95 · 10�3 M in DMF): 42. IR (KBr,cm�1): 3134 m(C–H)ar, 2952, 2922 m(C–H)al, 1562(m(C@C), m(C@N))ar, 1462, 1415 (d(C@C), d(C@N))ar,1093, 1027 d(C–H)ip, 800 d(C–H)oop. (Polyethylene,cm�1): 322 m(Pt–S), 303 m(Pt–Cl). 1H NMR (CDCl3 solu-tion, 250 MHz) d: SS: 5.91 [2H, s, CH(pz)], 5.80 [4H, s,NpzCH2S], 2.70 [4H, m, SCH2CH2S], 2.34 [6H, s, CH3(pz)],2.23 [6H, s, CH3(pz)] ppm. 13C{1H} NMR (CDCl3 solu-tion, 63 MHz,) d SS: 148.0–144.5 (pz-C), 140.8–140.0 (pz-C), 107.5, 105.2 (CH(pz)), 59.9 (NpzCH2S), 21.3 (SCH2

CH2S), 13.2–10.7 (CH3(pz)) ppm.

4.6. Complexes [Pt(NSSN)](BPh4)2 (NSSN = bddo (1),

bddn (2))

A solution of NaBPh4 (0.32 mmol) in 5 ml of acetoni-trile/methanol 1:1 was added dropwise with vigorous stir-ring to a solution of [PtCl2(NSSN)] (NSSN = bddo, bddn,0.16 mmol) in 10 ml of acetonitrile/methanol 1:1. The solu-tion was stirred at room temperature for 12 h. The yellow-ish solution was filtered to separate NaCl. When thevolume of the resultant solution had been reduced toroughly 5 ml, diethyl ether (5 ml) was added to induce pre-

cipitation. The resulting precipitate was then filtered andwashed with 5 ml of diethyl ether, yielding the desired com-pounds. No Pt(II) complex of this stoichiometry with bddhas ligand could be isolated.

4.7. Complex 1

Yield: 66% (0.12 g). Anal. Calc. for C64H66B2N4PtS2: C,65.58; H, 5.63; N, 4.78; S, 5.46. Found: C, 65.55; H, 5.63;N, 4.77; S, 5.42%. MS (m/z) (%)=266 (100%) [Pt(bddo)]2+.Conductivity (X �1 cm2 mol�1, 1.10 · 10�3 M in DMF):136. IR (KBr, cm�1): 3434 m(C–H)ar, 2987, 2927 m(C–H)al, 1578, 1552 (m(C@C), m(C@N))ar, 1478, 1426(d(C@C), d(C@N))ar, 1068, 1031 d(C–H)ip, 850 d(C–H)oop, 727 m(B–C), (Polyethylene, cm�1): 489, 467 m(Pt–N), 320 m(Pt–S). 1H NMR ([d6]-acetone solution,250 MHz) d: 7.34–6.78 [40H, Ph]; 6.25 [2H, s, CH(pz)],5.07 [2H, ddd, NpzCH2CH2S], 4.72 [2H, ddd,NpzCH2CH2S], 3.36 [2H, ddd, NpzCH2CH2S], 3.56 [2H,ddd, NpzCH2CH2S], 3.41 [2H, dd, SCH2CH2S], 2.68 [2H,dd, SCH2CH2S], 2.40 [6H, s, CH3(pz)], 1.90 [6H, s,CH3(pz)] ppm. 13C{1H} NMR ([d6]-acetone solution,63 MHz), d = 164.7–121.5 (Ph), 150.8, 145.8 (pz-C), 107.9(CH(pz)), 50.4 (NpzCH2CH2S), 38.4 (NpzCH2CH2S), 35.5(SCH2CH2S), 12.2 (CH3(pz)), 11.0 (CH3(pz)) ppm.195Pt{1H} NMR (CD3CN solution, 77.42 MHz) d = singletat �3884 ppm.

4.8. Complex 2

Yield: 70% (0.12 g). Anal. Calc. for C65H68B2N4PtS2: C,65.82; H, 5.78; N, 4.72; S, 5.41. Found: C, 65.80; H, 5.74;N, 4.71; S, 5.39%. MS (m/z) (%)=273 (100%) [Pt(bddn)]2+.Conductivity (X �1 cm2 mol�1, 0.95 · 10�3 M in DMF):126. IR (KBr, cm�1): 3446 m(C–H)ar, 2985, 2946 m(C–H)al, 1579, 1552 (m(C@C), m(C@N))ar, 1478, 1427(d(C@C), d(C@N))ar, 1068, 1030 d(C–H)ip, 802 d(C–H)oop, 721 m(B–C), (Polyethylene, cm�1): 489, 464 m(Pt–N), 318, 306 m(Pt–S). 1H NMR ([d6]-acetone solution,250 MHz) d: 7.33–6.77 [40H, Ph], 6.29 [2H, s, CH(pz)],5.26 [2H, ddd, NpzCH2CH2S], 4.88 [2H, ddd, Npz

CH2CH2S], 3.69 [2H, ddd, SCH2CH2N], 3.28 [6H, m,NpzCH2CH2S, SCH2CH2CH2S], 2.35 [2H, m, NpzCH2CH2CH2S], 2.44 [6H, s, CH3(pz)], 1.75 [6H, s, CH3(pz)ppm. 13C{1H} NMR (CDCl3 solution, 63 MHz,)d = 165.8–122.0 (Ph), 151.8, 146.2 (pz-C), 109.0 (CH(pz)),50.1 (NpzCH2CH2S), 36.0 (NpzCH2CH2S), 34.1 (SCH2

CH2CH2S), 22.6 (SCH2CH2CH2S), 12.7 (CH3(pz)), 11.6(CH3(pz)) ppm. 195Pt{1H} NMR (CD3CN solution,77.42 MHz) d = singlet at �3883 ppm.

4.9. X-ray crystal structures for compounds 1 and 2

Suitable crystals for X-ray diffraction of compounds[Pt(bddo)](BPh4)2 Æ 2CH3COCH3 Æ 2H2O (1) and [Pt(bddn)](BPh4)2 (2) were obtained through crystallisation from ace-tone solution.

Table 3Crystallographic data for [Pt(bddo)](BPh4)2 (1) and [Pt(bddn)](BPh4)2 (2)

1 2

Formula C70H82N4O4B2PtS2 C65H68N4B2PtS2

Formula weigh 1324.23 1186.06Temperature (K) 293(2) 293(2)Wavelength (A) 0.71073 0.71073System, space group monoclinic, C2/c monoclinic, P21/cUnit cell dimensions

a (A) 2.346(15) 19.876(6)b (A) 12.968(2) 15.885(6)c (A) 17.808(5) 20.906(7)a (�) 90 90b (�) 100.14(2) 121.21(2)c (�) 90 90

U (A3) 6444(4) 5646(3)Z 4 4Dcalc (g cm�3) 1.365 1.395l (mm�1) 2.293 2.603F(000) 2728 2424Crystal size (mm) 0.1 · 0.1 · 0.2 0.2 · 0.1 · 0.1hkl Ranges �39 6 h 6 42, 0 6 k 6 19, � 26 6 l 6 0 �30 6 h 6 27, �24 6 k 6 21, � 31 6 l 6 262h Range (�) 3.46–33.26 3.41–33.03Reflections collected/unique/[Rint] 9084/9084 [0.0495] 27708/16100 [0.0417]Absorption correction none noneData/restrains/parameters 9084/0/396 16100/5/667Goodness-of-fit on F2 1.184 1.105Final R indices [I > 2r(I)] R1 = 0.0333, wR2 = 0.0871 R1 = 0.0641, wR2 = 0.1517R indices (all data) R1 = 0.0366, wR2 = 0.0901 R1 = 0.1049, wR2 = 0.1725Largest difference in peak and hole (e A�3) 0.766 and �0.790 0.783 and �0.412


For compounds 1 and 2, a prismatic crystal was selectedand mounted on a MAR 345 diffractometer with an imageplate detector. Unit-cell parameters were determined fromautomatic centering of 167 reflections (1) and 61 reflectionsfor (2) (3 < h < 31�) and refined by least-squares method.Intensities were collected with graphite monochromatisedMo Ka radiation, using x/2h scan-technique. For 1 9084reflections were measured in the range 3.46 6 h 6 33.26.Reflections (8316) were assumed as observed applying thecondition I P 2r(I). For 2, 27708 reflections were mea-sured in the range 3.41 6 h 6 33.03, 16100 of which werenon-equivalent by symmetry (Rint (on I) = 0.041). Reflec-tions (10887) were assumed as observed applying the con-dition I P 2r(I). Lorentz-polarisation absorptioncorrections were made.

For 1, the structure was solved by direct methodsusing SHELXS computer program (SHELXS-97) [24] andrefined by full matrix least-squares method withSHELXL-97 [25] computer program, using 9084 reflections.The function minimised was

PwkF oj2 � jF cj2j2, where

w = [r(I) + 0.0469P + 0.9825P]�1, and P = (jFoj2 + 2jFc j2)/3. 4H atoms were located from a difference synthe-sis and refined with an overall isotropic temperature fac-tor and 35H atoms were computed and refined, using ariding model, with an isotropic temperature factor equalto 1.2 times the equivalent temperature factor of theatom which is linked.

For 2, the structure was solved by Patterson synthesis,using SHELXS computer program (SHELXS-97) [24] and

refined by full matrix least-squares method with SHELXL-97 [25] computer program, using 27708 reflections. Thefunction minimised was

PwjjF oj2 � jF cj2j2, where

w = [r2(I) + (0.0767P)2 + 1.8564P]�1, and P = (jFoj2 +2jFcj2)/3. All H atoms were computed and refined, usinga riding model, with an isotropic temperature factor equalto 1.2 times the equivalent temperature factor of the atomwhich is linked.

The final R(F) factor and Rw(F2) values as well as thenumber of parameters refined and other details concerningthe refinement of the crystal structures are gathered inTable 3.

5. Supplementary material

CCDC 616207 and 616206 contain the supplementarycrystallographic data for 1 and 2. These data can beobtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallo-graphic Data Centre, 12 Union Road, Cambridge CB21EZ, UK; fax: (+44) 1223-336-033; or e-mail: [email protected].

Acknowledgement

Support by the Spanish Ministerio de Educacion y Cul-tura (Project BQU2003-03582) is gratefully acknowledged.

http://www.ccdc.cam.ac.uk/conts/retrieving.html

http://www.ccdc.cam.ac.uk/conts/retrieving.html


References

[1] (a) P. Braunstein, F. Naud, Angew. Chem., Int. Ed 40 (2001) 680;(b) C.S. Slone, D.A. Weinberger, C.A. Mirkin, Prog. Inorg. Chem 48(1999) 233;(c) A. Bader, E. Lindner, Coord. Chem. Rev 108 (1991) 27;(d) L. Canovese, G. Chessa, G. Marangoni, B. Pitteri, P. Uguagliati,F. Visentin, Inorg. Chim. Acta 186 (1991) 79;(e) K. Boog-Wick, P.S. Pregosin, G. Trabesinger, Organometallics 17(1998) 3254;(f) S. Chattopadhyay, C. Sinha, B. Basu, A. Chakravorty, Organo-metallics 10 (1991) 1135;(g) C.K. Pal, S. Chattopadhyay, C. Sinha, A. Chakravorty, J.Organomet. Chem. 439 (1992) 91;(h) C. Sinha, D. Bandyopadhyay, A. Chakravorty, Inorg. Chem. 27(1998) 1173;(i) C. Lopez, S. Perez, X. Solans, M. Font-Bardıa, J. Organomet.Chem. 650 (2002) 258;(j) H.A. Ankersmit, P.T. Witte, H. Kooijman, M.T. Lakin, A.L. Spek,K. Goubitz, K. Vrieze, G. van Koten, Inorg. Chem. 35 (1996) 6035;(k) G. Chelucci, D. Muroni, A. Saba, F. Saccolini, J. Mol. Catal. A:Chem. 197 (2003) 27;(l) G. Chelucci, D. Muroni, G.A. Pinna, A. Saba, D. Vignola, J. Mol.Catal. A: Chem. 191 (2003) 1;(m) R.T. Stibrany, S. Fox, P.K. Bharadwaj, H.J. Schugar, J.A.Potenza, Inorg. Chem. 44 (2005) 8234;(n) G. Tresoldi, L. Baradello, S. Lanza, P. Cardiano, Eur. J. Inorg.Chem. (2005) 2423.

[2] (a) L. Canovese, F. Visentin, P. Uguagliati, V. Lucchini, G. Bandoli,Inorg. Chim. Acta 277 (1998) 247;(b) M. Basseti, A. Capone, M. Salamone, Organometallics 23 (2004)247;(c) M. Basseti, A. Capone, L. Mastrofrancesco, M. Salamone,Organometallics 22 (2003) 2535.

[3] (a) T.N. Sorrell, M.R. Malachowski, Inorg. Chem. 22 (1983) 1883;(b) J. Garcıa-Anton, J. Pons, X. Solans, M. Font-Bardıa, J. Ros,Eur. J. Inorg. Chem. (2003) 3952.

[4] (a) W.G. Haanstra, W.L. Driessen, J. Reedijk, U. Turpeinen, R.Hamalainen, J. Chem. Soc., Dalton Trans. (1989) 2309;(b) W.G. Haanstra, W.A.J.W. van der Donk, W.L. Driessen, J.Reedijk, M.G.B. Drew, J. Chem. Soc., Dalton Trans. (1990) 3123.

[5] W.G. Haanstra, W.A.J.W. van der Donk, W.L. Driessen, J. Reedijk,M.G.B. Drew, J.S. Wood, Inorg. Chim. Acta 176 (1990) 299.

[6] (a) W.G. Haanstra, W.L. Driessen, J. Reedijk, R. Frohlich, B. Krebs,Inorg. Chim. Acta 185 (1991) 175;(b) W.G. Haanstra, W.L. Driessen, R.A.G. de Graaff, J. Reedijk,Y.F. Wang, C.H. Stam, Inorg. Chim. Acta 186 (1991) 215.

[7] J. Garcıa-Anton, J. Pons, X. Solans, M. Font-Bardıa, J. Ros, Eur. J.Inorg. Chem. (2002) 3319.

[8] W.G. Haanstra, W.L. Driessen, J. Reedijk, J.S. Wood, ActaCrystallogr. C48 (1992) 1405.

[9] (a) M.A. Cinellu, S.S. Toccoro, G. Minghetti, A.L. Bandini, G.Banditelli, B. Bovio, J. Organomet. Chem. 372 (1989) 311;

(b) A. Boixassa, J. Pons, X. Solans, M. Font-Bardıa, J. Ros, Inorg.Chim. Acta 355 (2003) 254;(c) A. Boixassa, J. Pons, A. Virgili, X. Solans, M. Font-Bardia, J.Ros, Inorg. Chim. Acta 340 (2002) 49.

[10] F.P. Fanizzi, F.P. Intini, L. Maresca, G. Natile, J. Chem. Soc.,Dalton Trans. (1990) 199.

[11] D.A. White, Inorg. Synth. 13 (1972) 62.[12] (a) E. Pretsch, T. Clerc, J. Seibl, W. Simon, Tables of Determination

of Organic Compounds 13C NMR, 1H NMR, IR, MS, UV/Vis,Chemical Laboratory Practice, Springer-Verlag, Berlin, Germany,1989;(b) D.H. Williams, I. Fleming, Spectroscopic Methods in OrganicChemistry, McGraw-Hill, London, UK, 1995.

[13] K. Nakamoto, Infrared and Raman spectra of Inorganic andCoordination Compounds, John Wiley and Sons, New York, USA,1986.

[14] A. Rimola, M. Sodupe, J. Ros, J. Pons, Eur. J. Inorg. Chem. (2006)447.

[15] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.[16] P.H.M. Budzelaar, g NMR ver. 4.0, IvorySoft, Cherwell Scientific

Oxford, UK, 1997.[17] G.J. Grant, K.N. Patel, M.L. Helm, L.F. Mehne, D.W. Klinger,

D.G. VanDerveer, Polyhedron 23 (2004) 1361.[18] J. Garcıa-Anton, J. Pons, X. Solans, M. Font-Bardıa, J. Ros, Eur. J.

Inorg. Chem. (2003) 2992.[19] (a) G.J. Grant, I.M. Poullaos, D.F. Galas, S.C. Carter, D.G.

VanDerveer, J. Chem. Soc., Dalton Trans. (2002) 2973;(b) G.J. Grant, D.F. Galas, S.D.G. VanDerveer, Polyhedron 21(2002) 879;(c) G.J. Grant, S.M. Carter, I.M. Poullaos, A.L. Russell, D.G.VanDerveer, J. Organomet. Chem. 637–639 (2001) 683;(d) G.J. Grant, J.D. Pool, D.G. VanDerveer, J. Chem. Soc., DaltonTrans. (2003) 3981.

[20] A.J. Blake, R.O. Gould, A.J. Holder, T.I. Hyde, A.J. Lavery,M.O. Odulate, M. Schroder, J. Chem. Soc., Dalton Trans. (1994)627.

[21] (a) F. Contu, F. Demartin, F.A. Devillanova, A. Garau, F. Isaia, V.Lippolis, A. Salis, G. Verani, J. Chem. Soc., Dalton Trans. (1997)4401;(b) T.W. Green, R. Lieberman, N.M.J.A. Krause Bauer, W.B.Connick, Inorg. Chem. 44 (2005) 1955.

[22] (a) A. Boixassa, J. Pons, X. Solans, M. Font-Bardıa, J. Ros, Inorg.Chim. Acta 357 (2004) 827;(b) V. Montoya, J. Pons, X. Solans, M. Font-Bardıa, J. Ros, Inorg.Chim. Acta 358 (2005) 2763;(c) V. Montoya, J. Pons, X. Solans, M. Font-Bardıa, J. Ros, Inorg.Chim. Acta 359 (2006) 25.

[23] J. Garcıa-Anton, J. Pons, X. Solans, M. Font-Bardıa, J. Ros, ActaCrystallogr. E60 (2004) m1087.

[24] G.M. Sheldrick, SHELXS-97, Program for Crystal Structure Determi-nation, University of Gottingen, Germany, 1997.

[25] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure Refine-ment, University of Gottingen, Germany, 1997.

Synthesis of new platinum(II) complexes containing hybrid thioether–pyrazole ligands: Structural analysis by 1H and 13C{1H} NMR spectroscopy and X-ray crystal structures

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