Crystal structure and reactivity of mononuclear cationic palladium(II) and platinum(II) triphos complexes with phenyltin(IV) anions. The formation of polynuclear platinum-triphos ionic and covalent complexes

Article abstract of DOI:10.1016/S0277-5387(01)00716-1

The ionic complexes [M(triphos)Cl]X [M = Pd, X = Cl (1), SnCl₃ (1a), SnPh₂Cl₃ (1c); M = Pt, X = Cl (3), SnCl₃ (3a), SnPh₂Cl₃ (3c)], [M(triphos)Cl]₂X [X = SnPh₂Cl₄, M = Pd (1b), Pt (3b); X = PtCl₄, M = Pt (3d)] and [M(triphos)₂]X₂ [X = SnPh₂Cl₃, M = Pd (2), Pt (4)] where triphos = bis(2-diphenylphosphinoethyl)phenylphosphine, were synthesised and characterised by microanalysis, mass spectrometry, IR, ¹¹⁹Sn M?ssbauer, NMR (³¹P, ¹⁹⁵Pt and ¹¹⁹Sn) spectroscopies and conductivity measurements. The X-ray crystal structures of compounds 1b, 3b and 3c, where tetrachlorodiphenylstannate(IV) and trichlorodiphenylstannate(IV) act as counterions stabilising cationic metal complexes, are reported. These compounds contain the cation [M(triphos)Cl]⁺ with distorted square-planar geometry at palladium or platinum, triphos acting as a tridentate chelating ligand. The anions [SnPh₂Cl₄]^2- (1b, 3b) and [SnPh₂Cl₃]^- (3c) have trans-octahedral and distorted trigonal-bipyramidal environments for the metal, respectively. Although the dinegatively charged [SnPh₂Cl₄]^2- is counteracted by the presence of two singularly positively charged [M(triphos)Cl]⁺ species, interanion contacts via hydrogen bonds were found for 1b and 3b but were absent for compound 3c. The crystalline solids [M(triphos)₂][SnPh₂Cl₃]₂ M = Pd (2), Pt (4)] were formed via a chelate ring-opening reaction of [M(triphos)Cl]⁺ induced by triphos. The formation of heterometallic complexes by reaction of AgCl or Au(I) with the complex [Pt(triphos)₂][SnPh₂Cl₃]₂ (4), followed by ³¹P NMR in solution, did not take place. The presence of dangling arm phosphine oxide groups, on oxidation of complex 4 with H₂O₂, was detected. Other ring-opening reactions were observed by ³¹P NMR and conductivity measurements when solutions containing PtCl₂(PhCN)₂ and triphos in a molar ratio 3:2 were refluxed C₆H₆. Besides [Pt(triphos)Cl]₂[PtCl₄] (3d) and the ionic complex with a dinuclear anion, [Pt(triphos)Cl][Pt₂(triphos)Cl₅] (5), the covalent trinuclear complexes [{PtCl₂(Ph₂PCH₂CH₂) ₂PPh-P¹,P²}₂(P³, P³)PtCl₂] (6a, 6b) were formed as minor products. These latter diastereomeric species become the dominant species upon heating, being thermodynamically controlled complexes. Mixtures of 3d, 5, 6a and 6b converted to complex [Pt(triphos)Cl]Cl (3) by addition of triphos, chelate ring-closure reactions of 6a, 6b and the complex anion 5 occurring. With an excess of triphos (Pt:triphos = 3:4 or higher ratio), broad peaks reflecting fast equilibria between ring-opened and ring-closed products were found.

Full text of DOI:10.1016/S0277-5387(01)00716-1

Polyhedron 20 (2001) 855–868
www.elsevier.nl/locate/poly
Crystal structure and reactivity of mononuclear cationic
palladium(II) and platinum(II) triphos complexes with
phenyltin(IV) anions. The formation of polynuclear
platinum–triphos ionic and covalent complexes
M. Ine´s Garc´ıa-Seijo a, Alfonso Castin˜eiras a, Bernard Mahieu b, La´szlo´ Ja´nosi c,
Zolta´n Berente d,e, La´szlo´ Kolla´r c,e, M. Esther Garc´ıa-Ferna´ndez a,*
a Department of Inorganic Chemistry, Uni6ersity of Santiago de Compostela, A6da. de las Ciencias s/n, E-15782 Santiago de Compostela, Spain
b Inorganic Nuclear Chemistry Laboratory, Catholic Uni6ersity of Lou6ain, B-1348 Lou6ain-la-Neu6e, Belgium
c Department of Inorganic Chemistry, Janus Pannonius Uni6ersity, PO Box 266, H-7624 Pe´cs, Hungary
d Institute of Biochemistry, Uni6ersity Medical School, PO Box 99, H-7643 Pe´cs, Hungary
e Research Group for Chemical Sensors of the Hungarian Academy of Sciences, PO Box 266, H-7624 Pe´cs, Hungary
Received 2 October 2000; accepted 8 December 2000
Abstract
The ionic complexes [M(triphos)Cl]X [M=Pd, X=Cl (1), SnCl3 (1a), SnPh2Cl3 (1c); M=Pt, X=Cl (3), SnCl3 (3a), SnPh2Cl3
(3c)], [M(triphos)Cl]2X [X=SnPh2Cl4, M=Pd (1b), Pt (3b); X=PtCl4, M=Pt (3d)] and [M(triphos)2]X2 [X=SnPh2Cl3, M=Pd
(2), Pt (4)] where triphos=bis(2-diphenylphosphinoethyl)phenylphosphine, were synthesised and characterised by microanalysis,
mass spectrometry, IR, 119Sn Mo¨ssbauer, NMR (31P, 195Pt and 119Sn) spectroscopies and conductivity measurements. The X-ray
crystal structures of compounds 1b, 3b and 3c, where tetrachlorodiphenylstannate(IV) and trichlorodiphenylstannate(IV) act as
counterions stabilising cationic metal complexes, are reported. These compounds contain the cation [M(triphos)Cl]+ with
distorted square-planar geometry at palladium or platinum, triphos acting as a tridentate chelating ligand. The anions
[SnPh2Cl4]2− (1b, 3b) and [SnPh2Cl3]− (3c) have trans-octahedral and distorted trigonal-bipyramidal environments for the metal,
respectively. Although the dinegatively charged [SnPh2Cl4]2− is counteracted by the presence of two singularly positively charged
[M(triphos)Cl]+ species, interanion contacts via hydrogen bonds were found for 1b and 3b but were absent for compound 3c. The
crystalline solids [M(triphos)2][SnPh2Cl3]2 [M=Pd (2), Pt (4)] were formed via a chelate ring-opening reaction of [M(triphos)Cl]+
induced by triphos. The formation of heterometallic complexes by reaction of AgCl or Au(I) with the complex [Pt(t-
riphos)2][SnPh2Cl3]2 (4), followed by 31P NMR in solution, did not take place. The presence of dangling arm phosphine oxide
groups, on oxidation of complex 4 with H2O2, was detected. Other ring-opening reactions were observed by 31P NMR and
conductivity measurements when solutions containing PtCl2(PhCN)2 and triphos in a molar ratio 3:2 were refluxed C6H6. Besides
[Pt(triphos)Cl]2[PtCl4] (3d) and the ionic complex with a dinuclear anion, [Pt(triphos)Cl][Pt2(triphos)Cl5] (5), the covalent
trinuclear complexes [{PtCl2(Ph2PCH2CH2)2PPh-P1,P2}2(P3,P3)PtCl2] (6a, 6b) were formed as minor products. These latter
diastereomeric species become the dominant species upon heating, being thermodynamically controlled complexes. Mixtures of 3d,
5, 6a and 6b converted to complex [Pt(triphos)Cl]Cl (3) by addition of triphos, chelate ring-closure reactions of 6a, 6b and the
complex anion 5 occurring. With an excess of triphos (Pt:triphos=3:4 or higher ratio), broad peaks reflecting fast equilibria
between ring-opened and ring-closed products were found. © 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Palladium; Platinum; Triphosphine complexes; Diphenyltin(IV) anions; X-ray structures; NMR spectroscopy
1. Introduction
The platinum diphosphine complexes are among the
most studied in coordination chemistry [1] and their
catalytic importance, especially in asymmetric hydro-
* Corresponding author. Tel.: +34-981-563100 ext. 14241; Fax:
+34-981-597525.
E-mail address: qiegfq@usc.es (M.E. Garc´ıa-Ferna´ndez).
0277-5387/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0277-5387(01)00716-1

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M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
[SnPh2Cl3] which were suitable for X-ray diffraction to
be obtained. Using 3:2 platinum:triphos ratios the for-
mation of a Pt covalent trinuclear complex and a
dinuclear anionic complex, which undergo a ring-clo-
sure reaction to give [Pt(triphos)Cl]Cl, was detected by
31P NMR and conductivity measurements.
formylation, has been proved [2,3]. The [Pt(monophos-
phine)3Cl]+ cations have also been known for a long
time [4–7]. Due to their catalytic relevance in carbony-
lation reactions, a series of [Pt(chiral diphosphine)-
(monophosphine)Cl]+ ionic complexes [8] have been
characterised. However, relatively little is known about
the platinum complexes containing terdentate phospho-
rus ligands [9,10].
2. Experimental
Complexes containing both mono- and diphosphines
[11] are relevant not only in catalysis [12] but also in the
synthesis of biologically important derivatives [2]. In
fact, bis(ditertiaryphosphine) complexes of the type
[M(dppe)2]+ (M=Au, Ag, Cu) have attracted much
interest over the past decade as some of these com-
plexes have been shown to display antitumour activities
comparable to cisplatin [13,14]. Moderate cytotoxicity
was also found for [Pd(diphosphine)(phosphino-
arsine)]2+ and [Pd(diphosphine)Cl2] complexes as well
as for the products of their reaction with thiolate
ligands [15,16]. The polydentate phosphines are chelat-
ing systems or pendands [17–19] for many types of
metals and their properties can be altered to favour
different kinds of reactions. The reactions of [Pt-
(diphosphine)Cl2] with mono and bidentate phosphines
in the presence of tin(II) produce cationic complexes,
with a Pt–Sn bond and SnCl−3 as counterion [11,20].
The interaction of the linear triphosphine [triphos=
PhP(CH2CH2PPh2)2] with SnPh2Cl2 [21] leads to the
formation of a five-coordinate complex, SnPh2Cl2-
(triphos), where the phosphine seems to act as a
monodentate ligand. On the other hand, a chelate
ring-opening of [Pd(triphos)Br]Br can be induced by
oxidising agents giving the square-planar Pd(II) com-
plex [Pd(triphos-O)2][PdBr4] or the unusual square-
2.1. General procedures
Solvents were dried by conventional methods, dis-
tilled and kept under argon. Other reagents were of the
highest commercial grade available and were used as
received. Solvent evaporations were always carried out
under vacuum using a rotary evaporator and a vacuum
line. Microanalyses (C, H) were performed at the Uni-
versities of Santiago de Compostela and Janus
Pannonius.
2.2. Instrumentation
Fast atom bombardment (FAB) spectra were ob-
tained on a KRATOS MS 50 spectrometer using 3-ni-
trobenzyl alcohol as the matrix and electron spray mass
spectra were obtained on a Micromass VG-QUATTRO
spectrometer by injecting 0.5×10−4 M solutions at a
flow rate of 15 ml min−1 and using CH3CN/H2O/
HCOOH (1%) as the mobile phase. Infrared spectra
were recorded at ambient temperature as KBr pellets
(4000–500 cm−1) and Nujol mulls (500–100 cm−1) on
a Mattson Cygnus 100 spectrophotometer. The bands
are reported as: vs very strong, s strong, m medium and
sh shoulder. The 119Sn Mo¨ssbauer spectra were
recorded in constant acceleration mode on an Elscint
pyramidal
five-coordinate
Pd(II)
complex,
[Pd(triphos-O)2Br]Br [22] containing dangling arm
phosphine oxide groups. The combination of square-
planar Pd(II) or Pt(II) and linear Au(I) centres with
triphos in a single complex has been investigated, af-
fording novel bimetallic complexes by a chelate-ring
opening reaction, a process which was possible to re-
verse via Au(I) abstraction from PtAu(triphos)Cl3 [23].
However, no more examples of chelate-ring opening or
closure reactions concerning M(II)–triphos systems
(M=Pd, Pt) have been described yet. Likewise, as far
as we know, no crystal structures of compounds con-
taining [SnPh2Cl4]2− or [SnPh2Cl3]− anions stabilising
cationic metal complexes have been reported [24–29].
In this paper we study the modifications that [M-
(triphos)Cl]Cl (M=Pd, Pt) complexes can undergo on
the chloride counterion or the chelate rings. In order to
achieve this, the interactions of [M(triphos)Cl]Cl com-
plexes with SnCl2, SnPh2Cl2 and the triphos ligand in
different ratios are reported. Unusual sequences for the
reaction with SnPh2Cl2 allowed crystals of [M(triphos)-
Cl][SnPh2Cl4] (M=Pd, Pt) and [Pt(triphos)Cl]-
MVT4 Promeda counting instrument, with
a
Ca119mSnO3 source from Amersham as described previ-
ously [30]. The probe was maintained at a temperature
between 90 and 100 K, and the source was kept at
room temperature. The digital data were treated with
an iterative program and least square deconvoluted as a
linear combination of Lorentzian functions [31].
31P{1H} spectra were recorded on Bruker AMX500 and
Varian Inova 400 spectrometers at 202.46 MHz and
161.9 MHz, respectively. 195Pt and 119Sn NMR spectra
were recorded on a Bruker AMX500 spectrometer at
107.52 and 186.5 MHz, respectively. Chemical shifts are
reported relative to external standard 85% H3PO4 (31P),
1 M Na2PtCl6 ( (
195Pt) and SnMe4 119Sn); l is the
chemical shift in ppm; s singlet, d doublet, t triplet, dt
doublet of triplet, m multiplet, bs broad signal; J is the
coupling constant in Hz. Conductivities were obtained
at 25°C from 10−3 M solutions in CH3CN or DMF on
a WTW model LF-3 instrument. Conductivities were
also obtained from CH2Cl2 solutions on a Radelkis
(0K-102/1) instrument.

M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
857
2.3. Preparation of complexes
2.3.4. Synthesis of [Pd(triphos)Cl][SnPh2Cl3] (1c)
A solution of [Pd(triphos)Cl]Cl (0.2500 g, 0.3512
mmol) in dry CH2Cl2 (30 ml) was added dropwise to a
solution of SnPh2Cl2 (0.2414 g, 0.7024 mmol) in dry
acetone (50 ml). The resultant solution was stirred for
48 h, filtered off and the solid was precipitated with
Et2O. It was filtered off and dried in vacuo. Yield 89%,
m.p. \175°C. Anal. Found: C, 51.93; H, 3.91. Calc.
for C46H43P3PdSnCl4: C, 52.29; H, 4.11%. 31P{1H}
NMR (CD2Cl2): l 108.5 (t) [PB], l 44.1 (d) [PA]. 119Sn
NMR (CD2Cl2, −40°C): −239.7 (s). 119Sn Mo¨ssbauer:
QS (mm s−1): 2.67; IS (mm s−1): 1.25. IR (cm−1): 312s
[w(Pd–Cl)], 229vs [w(Sn–Cl)], 282m [was(Sn–C)], 225vs
[ws(Sn–C)]. MS (FAB): m/z (rel. intensity) 675 (100%,
[M+−SnPh2Cl3−]). \ (V−1 cm2 mol−1, CH3CN):
131.7.
2.3.1. Synthesis of [Pd(triphos)Cl]Cl (1)
A suspension of PdCl2 (0.1771 g, 0.9970 mmol) and
NaCl (0.1165 g, 1.9910 mmol) in H2O (25 ml) was
heated in a water bath until a clear solution formed.
This was allowed to cool to ambient temperature and
triphos (0.6000 g, 1.1220 mmol) in CH2Cl2 (30 ml) was
added dropwise. The resultant solution was stirred for 1
h at room temperature (r.t.) and solvent was removed
in vacuo to leave a white solid. The solid was filtered
off, washed with water, dried in vacuo and recrys-
tallised from CH2Cl2–n-hexane, to give colourless
prisms. Yield: 67%, m.p. \250°C. Anal. Found: C,
57.01; H, 4.90. Calc. for C34H33P3PdCl2: C, 57.31; H,
4.67%. 31P{1H} NMR (CDCl3): l 109.3 (t) [PB], l 44.2
(d) [PA] (2J(31PB–PA)=9.4 Hz). IR (cm−1): 318vs
[w(Pd–Cl)]. MS (FAB): m/z (rel. intensity) 675 (100%,
[M+−Cl−]). \ (V−1 cm2 mol−1, DMF): 91.5.
2.3.5. Synthesis of [Pd(triphos)2][SnPh2Cl3]2 (2)
To a solution of [Pd(triphos)Cl]Cl (0.1500 g, 0.2106
mmol) in dry CH2Cl2 (15 ml) a solution of SnPh2Cl2
(0.1448 g, 0.4212 mmol) in dry acetone (32 ml) was
added dropwise. The mixture reaction was stirred for 4
h and then a solution of triphos (0.1126 g, 0.2106
mmol) in dry CH2Cl2 (15 ml) was added slowly. The
resulting yellow solution was stirred for 18 h, filtered
off and solvents were removed in vacuo. Yield 77%,
m.p. 183°C. Anal. Found: C, 57.90; H, 5.00. Calc. for
C92H86P6PdSn2Cl6: C, 57.10; H, 4.50%. 31P{1H} NMR
(CD2Cl2): l 54.4 (bs) [PE], l 49.9 (s) [PD], l −12.7 (bs)
[PC]. 119Sn NMR (CD2Cl2, −40°C): −259.1 (s). IR
(cm−1): 250s [w(Sn–Cl)], 276m [was(Sn–C)], 245s
[ws(Sn–C)]. MS (FAB): m/z (rel. intensity) 1174 (7%,
[M2+ −2SnPh2Cl−3 ]), 587 (13%, [M2+ −2SnPh2Cl−3 /
2]). \ (V−1 cm2 mol−1, CH3CN): 194.7.
2.3.2. Synthesis of [Pd(triphos)Cl][SnCl3] (1a)
SnCl2 (0.0533 g, 0.2807 mmol) was dissolved in a 1:1
mixture of MeOH:CH2Cl2 (8 ml) and added dropwise
to a solution of [Pd(triphos)Cl]Cl (0.2000 g, 0.2807
mmol) in CH2Cl2 (25 ml). The final solution was stirred
for 18 h and then solvents were removed in vacuo until
only a small volume remained. The complex was pre-
cipitated with Et2O, filtered off, recrystallised from
CH2Cl2–Et2O and dried in vacuo. Yield 82%, m.p.
(dec.) \200°C. Anal. Found: C, 44.50; H, 3.87. Calc.
for C34H33P3PdSnCl4: C, 45.22; H, 3.69%. 31P{1H}
NMR (CD2Cl2): l 110.8 (s) [PB], l 46.3 (s) [PA]. 119Sn
NMR (CD2Cl2, −40°C): −62.5 (s). IR (cm−1): 310 vs
[w(Pd–Cl)], 312 vs, 296 vs [w(Sn–Cl)]. MS (FAB): m/z
(rel. intensity) 675 (100%, [M+−SnCl3−]). \ (V−1 cm2
mol−1, CH3CN): 126.8.
This complex can also be prepared using
Pd:Sn:triphos in the ratio of 2:2:2.
a
2.3.6. Synthesis of [Pt(triphos)Cl]Cl (3)
2.3.3. Synthesis of [Pd(triphos)Cl]2[SnPh2Cl4] (1b)
Method 1. The compound was prepared as described
earlier [22]. A solution of triphos (1.0000 g, 1.8706
mmol) in CH2Cl2 (50 ml) was added dropwise to a
solution of K2PtCl4 (0.7192 g, 1.7326 mmol) in H2O (35
ml). The final solution was stirred for 1 h and solvents
removed in vacuo to leave a white precipitate. The solid
was filtered off, washed with water, dried in vacuo and
recrystallised from CH2Cl2–n-hexane, to give colourless
prisms. Yield 70%. Method 2. A solution of triphos
(0.5340 g, 1.0000 mmol) in benzene (3 ml) was added to
the refluxing yellow solution of PtCl2(PhCN)2 (0.4720
g, 1.0000 mmol) in benzene (45 ml). After a few min-
utes a fine white precipitate was formed. The mixture
was stirred for 1 h, then cooled to r.t. The solid was
filtered off, washed with benzene, and dried under
reduced pressure to give [Pt(triphos)Cl]Cl as white pow-
der. Yield 91%, m.p. 200°C. Anal. Found: C, 51.18; H,
4.33. Calc. for C34H33P3PtCl2: C, 51.01; H, 4.15%.
To a solution of SnPh2Cl2 (0.1207 g, 0.3512 mmol) in
dry acetone (25 ml), a solution of [Pd(triphos)Cl]Cl
(0.2500 g, 0.3512 mmol) in dry CH2Cl2 (30 ml) was
added dropwise. The mixture reaction was stirred for
24 h, filtered off, n-hexane was added and solvents were
slowly evaporated in air. The resulting crystals were
filtered off and dried in vacuo. By recrystallisation in
acetone–CH2Cl2 suitable crystals for X-ray diffraction
were obtained. Yield 40%, m.p. (dec.) \200°C. Anal.
Found: C, 54.12; H, 4.36. Calc. for C80H76P6Pd2SnCl6:
C, 54.29; H, 4.34%. 31P{1H} NMR (CD2Cl2): l 110.2
(s) [PB], l 46.1 (s) [PA]. 119Sn NMR (CD2Cl2, −40°C):
−253.2 (s). 119Sn Mo¨ssbauer: QS (mm s−1): 3.55; IS
(mm s−1): 1.33. IR (cm−1): 311s [w(Pd–Cl)], 228vs
[w(Sn–Cl)], 283m [was(Sn–C)], 240sh [ws(Sn–C)]. MS
(FAB): m/z (rel. intensity) 675 (100%, [M+−
SnPh2Cl24−]). \ (V−1 cm2 mol−1, CH3CN): 121.8.

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M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
1
31P{1H} NMR (CDCl3): l 83.7 (s) [PB, J(31P–195Pt)=
evaporated in air. The resulting systoles were filtered
off, washed with Et2O and dried in vacuo. Crystals
suitable for X-ray diffraction were obtained by recrys-
tallisation in CH2Cl2–acetone. Yield 88%, m.p. 150°C.
Anal. Found: C, 48.49; H, 3.85. Calc. for
C46H43P3PtSnCl4: C, 48.28; H, 3.79%. 31P{1H} NMR
(CDCl3): l 83.2 (s) [PB, 1J(31P–195Pt)=3047 Hz], l 39.6
(s) [PA, 1J(31P–195Pt)=2467 Hz]. 195Pt NMR
3015 Hz; 2J(31PB–PA)= 3.1 Hz], l 39.8 (s) [PA, 1J(31P–
195Pt)=2484 Hz; J(31PB–PA)= 3.1 Hz]. 195Pt NMR
2
(CDCl3): −4858.3 (dt) [PB, 1J(31P–195Pt)=3015 Hz;
PA, J(31P–195Pt)=2484 Hz]. IR (cm−1): 320vs, 314sh
1
[w(Pt–Cl)]. MS (FAB): m/z (rel. intensity) 764 (100%,
[M+−Cl−]). \ (V−1 cm2 mol−1, DMF): 82.9.
1
(CDCl3+DMSO-d6): −4859 (dt) [PB, J(31P–195Pt)=
2.3.7. Synthesis of [Pt(triphos)Cl][SnCl3] (3a)
3034 Hz; PA, 1J(31P–195Pt)=2470 Hz]. 119Sn Mo¨ss-
bauer: QS (mm s−1): 2.96; IS (mm s−1): 1.23. IR
(cm−1): 330s, 319m [w(Pt–Cl)], 237sh [w(Sn–Cl)], 282m
[was(Sn–C)], 227vs [ws(Sn–C)]. MS (FAB): m/z (rel.
intensity) 764 (91%, [M+−SnPh2Cl3−]). \ (V−1 cm2
mol−1, CH3CN): 123.0.
SnCl2 (0.0474 g, 0.2498 mmol) was dissolved in a 1:1
mixture of MeOH:CH2Cl2 (6 ml). This was added
dropwise to a solution of [Pt(triphos)Cl]Cl (0.2000 g,
0.2498 mmol) in CH2Cl2 (25 ml). The final solution was
stirred for 7 h, after which solvents were removed in
vacuo. A pale yellow solid was deposited. This was
recrystallised from CH2Cl2–Et2O and dried in vacuo.
Yield 60%, m.p. \200°C. Anal. Found: C, 40.70; H,
3.60. Calc. for C34H33P3PtSnCl4: C, 41.24; H, 3.36%.
2.3.10. Preparation of [Pt(triphos)Cl]2[PtCl4] (3d)
See Table 4.
1
31P{1H} NMR (CDCl3): l 86.3 (s) [PB, J(31P–195Pt)=
2.3.11. Synthesis of [Pt(triphos)2][SnPh2Cl3]2 (4)
3035 Hz], l 42.3 (d) [PA, 1J(31P–195Pt)=2477 Hz]. 195Pt
A solution of 3 (0.2376 g, 0.2967 mmol) in dry
CHCl3 (32 ml) was added dropwise to a solution of
SnPh2Cl2 (0.1020 g, 0.2967 mmol) in dry acetone (20
ml). The mixture reaction was stirred for 6 h and then
a solution of triphos (0.1586 g, 0.2967 mmol) in CHCl3
(18 ml) was slowly added. The resulting yellow solution
was stirred for 24 h, filtered off and the solvents were
evaporated in air and a yellow crystalline solid formed.
The solid was recrystallised from CH2Cl2–acetone–
EtOH. White crystals were obtained, filtered off,
washed with Et2O and dried in vacuo. Yield 52%, m.p.
122°C. Anal. Found: C, 54.00; H, 4.10. Calc. for
C92H86P6PtSn2Cl6: C, 54.60; H, 4.29%. 31P{1H} NMR
NMR (CDCl3): −4858 (dt) [PB, J(31P–195Pt)=3038
1
Hz; PA, J(31P–195Pt)=2482 Hz]. 119Sn NMR (CD2Cl2,
1
−40°C): −60.8 (s). IR (cm−1): 312vs [w(Pt–Cl)], 315s,
294vs [w(Sn–Cl)]. MS (FAB): m/z (rel. intensity) 764
(100%, [M+−SnCl3−]). \ (V−1 cm2 mol−1, CH3CN):
126.8.
2.3.8. Synthesis of [Pt(triphos)Cl]2[SnPh2Cl4] (3b)
To a solution of SnPh2Cl2 (0.1073 g, 0.3122 mmol) in
dry acetone (25 ml), a solution of 1 (0.2500 g, 0.3122
mmol) in EtOH (30 ml) was added dropwise. The
mixture reaction was stirred for 24 h, filtered off and
solvents were slowly evaporated in air. The resulting
crystals were filtered off and dried in vacuo. By recrys-
tallisation in acetone–EtOH crystals suitable for X-ray
diffraction were obtained. Yield 69%, m.p. \200°C.
Anal. Found: C, 49.40; H, 4.06. Calc. for
C80H76P6Pt2SnCl6: C, 49.41; H, 3.94%. 31P{1H} NMR
(CDCl3): l 83.3 (s) [PB, 1J(31P–195Pt)=3045 Hz], l 39.6
1
(CDCl3+DMSO-d6): l 38.4 (s) [PD,E, J(31P–195Pt)=
2352 Hz]. 195Pt NMR (CD2Cl2): −5098 (m). 119Sn
NMR (CD2Cl2): −256.0. 119Sn Mo¨ssbauer: QS (mm
s
−1): 2.81; IS (mm s−1): 1.23. IR (cm−1): 250s [w(Sn–
Cl)], 279m [was(Sn–C)], 245m [ws(Sn–C)]. MS (FAB):
m/z (rel. intensity) 1263 (9%, [M2+ −2SnPh2Cl3−]); MS
(ES) 632 (100%, [M2+ −2SnPh2Cl3−/2]). \ (V−1 cm2
mol−1, CH3CN): 200.5.
The same compound was obtained when the ratio
Pt:Sn:triphos was 1:2:1. In this case recrystallisation
was not necessary.
(s) [PA, J(31P–195Pt)=2468 Hz]. 195Pt NMR (CDCl3):
1
−4856 (dt) [PB, J(31P–195Pt)=3053 Hz; PA, J(31P–
195Pt)=2469 Hz]. 119Sn NMR (CD2Cl2): −177.4 (s).
119Sn Mo¨ssbauer: QS (mm s−1): 3.61; IS (mm s−1):
1.30. IR (cm−1): 326vs [w(Pt–Cl)], 227vs [w(Sn–Cl)],
279m [was(Sn–C)], 240sh [ws(Sn–C)]. MS (FAB): m/z
(rel. intensity) 764 (92%, [M+−SnPh2Cl42−]). \ (V−1
cm2 mol−1, CH3CN): 164.1.
1
1
2.3.12. Preparation of [Pt(triphos)Cl][Pt2(triphos)Cl5]
(5)
See Table 4.
2.3.9. Synthesis of [Pt(triphos)Cl][SnPh2Cl3] (3c)
2.3.13. Preparation of [Pt3(triphos)2Cl6] (6a, 6b)
To a solution of SnPh2Cl2 (0.0859 g, 0.2497 mmol) in
dry acetone (25 ml), a solution of 1 (0.2000 g, 0.2497
mmol) in dry CH2Cl2 (25 ml) was added dropwise. The
reaction mixture was stirred for 24 h and after that
another solution of SnPh2Cl2 (0.0859 g, 0.2497 mmol)
in dry acetone (25 ml) was slowly added. The solution
was stirred for 24 h, filtered off and solvents were
See Table 4.
2.4. Reactions
2.4.1. Titration of complex 3 with AgCl
To a solution of 3 (0.0150 g, 0.0187 mmol) in CDCl3
(0.5 ml), AgCl (0.0027 g, 0.0187 mmol) was added as a

M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
859
solid. The mixture reaction was stirred for 12 h and the
31P{1H} NMR spectrum was recorded.
was dissolved in DMSO-d6 (0.5 ml) and after 12 h the
31P{1H} NMR spectrum was recorded. To the clear
solution SnPh2Cl2 (0.0068 g, 0.0198 mmol) in CD2Cl2
(0.4 ml) was added and after 12 h the 31P{1H} NMR
spectrum was recorded.
2.4.2. Titration of complex 3c with Au(I)
Solutions of Au(I) were prepared by treating Au with
HCl and HNO3 in an oil bath (120°C) and reduction
from Au(III) to Au(I) with 2,2-thiodiethanol (thiodigly-
col) as was indicated in the literature [23,32,33]. A
solution of Au(I) (0.0100 g of Au, 0.0508 mmol),
prepared as described previously, in MeOH (1 ml), was
added dropwise to a solution of complex 3c (0.0581 g,
0.0508 mmol) in CDCl3 (1 ml). After 12 h a 31P{1H}
NMR spectrum was recorded. This procedure was re-
peated after additions of two and three molar equiva-
lents of Au(I).
2.5. X-ray diffraction studies
Colourless prismatic crystals of 1b, 3b and 3c were
mounted on glass fibres and used for data collection.
Cell constants and an orientation matrix for data col-
lection were obtained by least-squares refinement on
the diffraction data from 25 reflections in the ranges
8.76°BqB17.92° (1b), 8.96°BqB17.95° (3b) and
10.74°BqB18.00° (3c) in an Enraf–Nonius Mach3
automatic diffractometer [34]. Data were collected at
,
293 K using Mo Ka radiation (u=0.71073 A) and the
2.4.3. Titration of complex 4 with Au(I)
ꢀ scan technique and corrected for Lorentz and polari-
sation effects [35]. A semi-empirical absorption correc-
tion (c scan) was made [36] for 1b and an empirical
absorption correction was made [37] for 3b and 3c.
The structures were solved by direct methods [38],
which revealed the positions of all non-hydrogen
atoms, and refined on F2 by a full-matrix least-squares
procedure using anisotropic displacement parameters
[39]. The C35 and C36 atoms for 1b were found to be
disordered over two sites (C351 and C352, C361 and
C362, each with an occupancy of approximately 0.5).
All the hydrogen atoms except those of the disordered
C atoms (1b) were located in their calculated positions
Solutions of Au(I) were prepared as above. A solu-
tion of Au(I) (0.0039 g of Au, 0.0198 mmol), prepared
as described previously, in MeOH (0.3 ml), was added
dropwise to a solution of complex 4 (0.0200 g, 0.0099
mmol) in CDCl3 (0.6 ml). After 12 h the 31P{1H} NMR
spectrum was recorded.
2.4.4. Titration of complex 4 with AgCl
To a solution of complex 4 (0.0200 g, 0.0099 mmol)
in CDCl3 (0.6 ml) AgCl (0.0028 g, 0.0198 mmol) was
added as a solid. The reaction mixture was stirred for
12 h and a white solid was obtained. DMSO-d6 (0.5 ml)
was added and the 31P{1H} NMR spectrum of the
resulting solution was recorded.
,
(C–H 0.93–0.97 A) and refined using a riding model.
For 3c relatively large positive peaks were found in the
final difference Fourier map, but these were all error
peaks located near the Sn and Pt atoms. Atomic scat-
tering factors were obtained with the use of interna-
tional tables for X-ray crystallography [40]. Molecular
graphics were produced with the use of drawing pro-
grams such us PLATON [36] (1b) and ZORTEP [41] (1b,
3b, 3c).
2.4.5. Oxidation of complex 4 with H2O2 and reaction
with SnPh2Cl2
To a solution of complex 4 (0.0200 g, 0.0099 mmol)
in CDCl3 (0.6 ml) H2O2 (100 ml, 6%) was added.
Immediately a white precipitate was obtained. The solid
3. Results and discussion
Fig. 1 shows the complexes studied. Complexes 1 and
3 were prepared using a variation [42] of a literature
method [43]. In accordance with Scheme 1, compounds
1 and 3 can also be obtained in a very good yield (91%,
3) by direct interaction of MCl2(PhCN)2 with triphos in
refluxing benzene for 2 h. Complexes 1a and 3a were
afforded by addition of SnCl2 to solutions of [M-
(triphos)Cl]Cl in a 1:1 molar ratio.
Crystals of compounds 1b, 3b and 3c suitable for
X-ray diffraction were prepared as showed in Eq. (1)
(1b, 3b) and Eq. (2) (3c) respectively, using the solvents
and conditions described in Section 2.
Fig. 1. Marking of the phosphorus atoms in ionic and covalent
complexes.

860
M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
In both cases (2:2 and 1:2 ratios), some diphenyl-
tin(IV) chloride remained in solution. Solutions con-
taining [M(triphos)Cl]2[SnPh2Cl4] and SnPh2Cl2 (Eq.
(1)) under stirring reacted with two molar equivalents
of triphos (M:Sn:triphos=2:2:2), giving rise to crys-
talline solids characterised as [Pd(triphos)2][SnPh2Cl3]2
(2) and [Pt(triphos)2][SnPh2Cl3]2 (4) (Eq. (3)).
[M(triphos)Cl]2[SnPh2Cl4]+SnPh2Cl2+2triphos
“[M(triphos)2][SnPh2Cl3]2(solid)
+[M(triphos)2]Cl2(solution)
(3)
The reaction under stirring of one molar equivalent
of triphos with solutions containing [M(triphos)Cl]-
[SnPh2Cl3] and SnPh2Cl2 (Eq. (2)) (Pt:Sn:triphos=
1:2:1) led to the complexes 2 (M=Pd) and 4 (M=Pt)
as the only products (Eq. (4)).
[M(triphos)Cl][SnPh2Cl3]+SnPh2Cl2+triphos
“[M(triphos)2][SnPh2Cl3]2
(4)
Other Pt:Sn:triphos ratios, 2:2:3, 1:2:3 or 1:3:1, did
not give rise to new compounds.
Using PtCl2(PhCN)2 and triphos in a 3:2 ratio
(Scheme 2) the dominant product formed was the kinet-
ically controlled ionic complex [Pt(triphos)Cl]2[PtCl4]
(3d) which can be converted into the ionic complex
[Pt(triphos)Cl][Pt2(triphos)Cl5] (5) and the neutral
Pt3(triphos)2Cl6 (6a, 6b) thermodynamically controlled
complexes.
Scheme 1. The formation of ionic palladium and platinum complexes
at M:triphos=(1:1=2:2) and 1:2 ratios.
2[M(triphos)Cl]Cl+2SnPh2Cl2
3.1. X-ray structures
“[M(triphos)Cl]2[SnPh2Cl4](crystals)+SnPh2Cl2(solution)
A molecular drawing of compounds 1b and 3b is
shown in Fig. 2. Table 1 summarises the crystal
parameters, data collection and refinement for com-
pounds 1b, 3b, and 3c. Selected bond distances and
angles for complexes 1b, 3b and 3c are listed in Table 2.
(1)
[M(triphos)Cl]Cl+2SnPh2Cl2
“[M(triphos)Cl][SnPh2Cl3](crystals)+SnPh2Cl2(solution)
(2)
Scheme 2. The formation of ionic and covalent platinum complexes at Pt:triphos=3:2 ratio and their transformation into 3 upon addition of extra
triphos.

M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
861
83.71(8), 164.08(8)° for 1b, 84.61(9), 84.87(9),
165.57(9)° for 3b, 85.07(4), 86.25(4), 169.00(4)° for 3c,
were indicative of the distorted square-planar environ-
ment at the metal centre.
The phenyl ring planes of the cation (I–V) as well as
the best coordination plane at the metal C, are defined
in Table 2. The M atom departs from C by 0.059 (1b),
,
0.061 (3b) and 0.128 A (3c) compared to the mean
,
values of 0.127 (1b), 0.130 (3b) and 0.016 A (3c) for
atoms defining the plane. The less crowded environ-
ment of P(2) led to a phenyl plane III almost perpendic-
ular to the coordination plane C in complexes 1b and
3b. However, the presence of a different counterion
(SnPh2Cl−3 ) in 3c resulted in a lower III–C dihedral
angle of 68.46°.
The dianion [SnPh2Cl4]2− of compounds 1b and 3b
showed a trans-octahedral geometry with the phenyl
rings in coplanarity. The Sn–C and Sn–Cl distances of
,
2.144(9) and 2.564(2), 2.584(2) A (1b), 2.143(11) and
,
2.569(3), 2.581(2) A (3b), respectively, were in the ex-
pected range although the Sn–Cl bonds are longer than
those found for [C10H9ONH]2[SnPh2Cl4] where this di-
anion stabilises two 8-methoxyquinolinium cations [29].
The angles C–Sn–C [180.00(1)o], C–Sn–Cl [89.90(2),
90.10(2)° (1b)] and [89.80(3), 90.20(3)° (3b)] and trans
Cl–Sn–Cl [180.00(0)o] are also in accordance with a
trans-octahedral arrangement. Table 2 defines the
phenyl ring planes VI and VII as well as the equatorial
coordination plane at the tin atom C%. The dihedral
angles VI–C% of 88.78 (1b), 88.39° (3b), where Sn does
not depart from C%, are in agreement with a dianion
which deviates slightly from a standard octahedron
[29].
Fig. 2. ORTEP view and numbering scheme of [M(triphos)Cl]2-
[SnPh2Cl4] (M=Pd) (1b), Pt (3b).
Crystals of 1b (M=Pd) and 3b (M=Pt) consist of two
monocations [M(triphos)Cl]+ which are symmetrically
located in relation to one dianion, [SnPh2Cl4]2−, the tin
atom being the centre of symmetry. Fig. 3 illustrates the
structure of [Pt(triphos)Cl][SnPh2Cl3] (3c) which con-
sists of one monocation [Pt(triphos)Cl]+ and one
monoanion [SnPh2Cl3]−. The triphosphine in the
monocations is bonded to the metal in a double chelate
fashion through the three P atoms, acting as a triden-
tate ligand. One chloride completes the distorted
square-planar environment at the palladium or plat-
inum. The M–P bond distances for the compounds (1b,
The anion [SnPh2Cl3]− present in compound 3c has a
slightly distorted trigonal-bipyramidal structure with
phenyl rings in equatorial positions (C–Sn–C angle
132.90(2)°). The Sn–C bond lengths of 2.129(5) and
,
2.130(4) A and the Sn–Cl bond distances of 2.347(1),
,
2.526(1) and 2.540(1) A were slightly shorter than those
found for [SnPh2Cl4]2−
.
The angles C–Sn–Cl
[87.65(6)–132.90(2)°] and Cl–Sn–Cl [87.33(6), 87.65(6),
174.98(6)°] were consistent with the trigonal-bipyrami-
dal environment at the tin atom. The orientation of the
phenyl ring planes labelled VI and VII with respect to
the coordination plane C% (Table 2) was similar, giving
the dihedral angles VI–C% 51.54° and C%–VII 58.20°.
All interionic H···Cl contacts for 1b and 3b (cation–
anion, cation–cation and anion–anion) agree with the
H···A distances and angular criteria for weak H-bonds.
No anion–anion interactions were found for complex
3c. This absence of H···Cl interactions between
SnPh2Cl−3 anions can be attributed to their arrange-
ment in opposite senses in the unit cell and their
separation by the two cations. The only H···Cl interca-
tionic interaction found is due to C–H of the phenyl
ring plane III of one cation and the chloro bound to
,
2.323(2) [P(1)], 2.218(2) [P(2)], 2.321(2) [P(3)] A; 3b,
,
2.315(3) [P(1)], 2.210(3) [P(2)], 2.309(3) [P(3)] A; 3c,
,
2.301(1) [P(1)], 2.212(1) [P(2)], 2.299(1) [P(3)] A) were
very similar to those reported for complexes 1 [44] and
3 [23]. As occurred for 1 and 3 the M–P(2) bond
distances in all cases were shorter than the M–P termi-
nal bond due to the double chelate effect of triphos.
M–Cl bond lengths 2.358(2) (1b), 2.364(2) (3b) and
,
2.353(1) A (3c) were in the expected range. The P–M–
Cl angles, 96.18(8), 97.02(8), 176.58(9)° for 1b, 95.25
(9), 95.84(9), 176.56(10)° for 3b, 93.64(4), 94.33(4),
174.34(4)° for 3c, and the P–M–P angles, 83.64(8),

862
M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
platinum in the other cation. The SnPh2Cl−3 ions take
part in H···Cl anion–cation interactions through the
C–H bonds of the phenyl substituents on the terminal
phosphorus of the cations.
found for palladium and platinum dichloro complexes
[45]. The most abundant peak at m/z=632 found in
the electron spray mass spectrum (ESMS) [46,47] of 4
was consistent with the presence in solution of [Pt-
(triphos)2]2+. The FAB spectra were also consistent
with the presence of the [M(triphos)2]2+ cation in both
complexes 2 and 4.
The only H···Cl intraionic interactions for 1b
,
[2.709(8), 2.726(8), 2.804(4) A with calculated C–H···Cl
angles of 151.89, 152.61, 139.09°, respectively] and for
,
3b [2.733(8), 2.723(5), 2.799(8) A with calculated C–
H···Cl angles 149.43, 152.40, 140.44°, respectively] cor-
responded to intracationic contacts. However, for 3c
both intracationic and intra-anionic contacts were ob-
3.3. 119Sn Mo¨ssbauer spectra
The QS and IS parameters were in agreement with
coordination numbers around tin: six in complexes with
the anion [SnPh2Cl4]2− (1b, 3b) and five in complexes
with the anion [SnPh2Cl3]− (1c, 3c, 4). These results
were also in accordance with the results found by X-ray
diffraction and infrared spectra.
,
served. These interactions were 2.814(7), 2.796(2) A
(c–c), and 2.706(7), 2.798(6) A (a–a) with C–H···Cl
angles of 147.36, 144.81° (c–c), and 117.54, 115.52°
(a–a), respectively.
,
3.2. Mass spectra
3.4. NMR spectra
FAB MS spectra for 1, 1a, 1b, 1c and 3, 3a, 3b, 3c
showed one base peak corresponding to the [Pd-
(triphos)Cl]+ (675) and [Pt(triphos)Cl]+ (764) cations,
respectively, following the tendency of fragmentation
3.4.1. Palladium– and platinum–triphos complexes
Fig. 1 shows the marking of the phosphorus atoms in
the ionic and covalent complexes studied. The 31P{1H}
Table 1
Crystallographic data for compounds 1b, 3b and 3c
1b
3b
3c
Empirical formula
Formula weight
Temperature (K)
C
80H76Cl6P6Pd2Sn
C80H76Cl6P6Pt2Sn
1944.79
293(2)
C46H43Cl4P3PtSn
1144.29
293(2)
1764.42
293(2)
,
Wavelength (A)
0.71073
0.71073
0.71073
Crystal size (mm)
Colour, habit
0.35×0.10×0.10
colourless, prisms
monoclinic
P21/n
0.35×0.15×0.10
colourless, prisms
monoclinic
P21/n
0.35×0.25×0.25
colourless, prisms
triclinic
Crystal system
Space group
Unit cell dimensions
(
P1
,
a (A)
9.904(2)
9.911(2)
11.425(3)
12.723(2)
16.679(2)
70.11(1)
83.74(2)
84.11(2)
2260.6(7)
2
1.681
4.017
1120
,
b (A)
19.727(2)
20.158(2)
90.00
100.52(3)
90.00
3872.0(3)
2
1.516
19.821(5)
20.140(7)
90.00(—)
100.64(2)
90.00(—)
3889.0(2)
2
1.661
4.280
1908
,
c (A)
h (°)
i (°)
k (°)
3
,
Volume (A )
Z
Calculated density (Mg m−3
)
Absorption coefficient (mm−1
F(000)
)
1.153
1780
q range for data collection (°)
Index ranges
2.30–26.34
−125h50
05k524
−245l525
8330
2.15–26.29
05h512
−245k50
−255l524
8869
2.36–26.37
−145h514
−145k515
05l520
9524
Reflections collected
Independent reflections
Absorption correction
Max. and min. transmission
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices a
7865 [Rint=0.0868]
semi-empirical
0.957 and 0.927
7865/0/450
0.930
7883 [Rint=0.1145]
empirical
1.000 and 0.403
7883/431
0.987
9195 [Rint=0.0227]
empirical
1.000 and 0.599
9194/668
1.005
R1=0.0288,
wR2=0.0714
2.024 and –0.975
R1=0.0570, wR2=0.1008
R1=0.0452, wR2=0.0797
−3
,
Largest difference peak and hole (e A
)
0.640 and –0.954
0.799 and –2.042
a [I\2|(I)].

M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
863
Table 2
,
Selected distances (A) and angles (°) for compounds 1b, 3b and 3c
1b
3b
3c
[Pd(triphos)Cl]2[SnPh2Cl4]
[Pt(triphos)Cl]2[SnPh2Cl4]
[Pt(triphos)Cl][SnPh2Cl3]
Bond distances
P–M
2.218(2)
2.321(2)
2.323(2)
2.358(2)
2.144(9)
2.210(3)
2.309(3)
2.315(3)
2.364(2)
2.143(1)
2.212(1)
2.299(1)
2.301(1)
2.353(1)
2.129(5)
2.130(4)
2.347(1)
2.526(1)
M–Cl
Sn–C
Sn–Cl
2.564(2)
2.584(2)
2.569(3)
2.581(2)
Bond angles
P–M–P
83.64(8)
83.71(8)
164.08(8)
96.18(8)
97.02(8)
176.58(9)
180.00(1)
89.90(2)
90.10(2)
84.61(9)
84.87(9)
165.57(9)
95.25(9)
95.84(9)
176.56(1)
180.00(1)
89.80(3)
90.20(3)
85.07(4)
86.25(4)
169.00(4)
93.64(4)
94.33(4)
174.34(4)
132.90(2)
87.65(6)
89.50(1)
90.55(1)
91.81(1)
92.14(1)
108.95(1)
118.16(1)
132.90(2)
87.33(6)
87.65(6)
174.98(6)
84.36
P–M–Cl
C–Sn–C
C–Sn–Cl
Cl–Sn–Cl
180.00(0)
180.00(0)
a
I–II
71.19
88.57
64.86
88.78
80.40
88.57
65.67
88.39
III–C
IV–V
VI–C%
C%–VII
68.46
68.75
51.54
58.20
a Angles between planes defined as: I (C21–C26)P1 (1b, 3b), (C31–C36)P1 (3c); II (C31–C36)P1 (1b, 3b), (C41–C46)P1 (3c); III (C41–C46)P2 (1b,
3b), (C51–C56)P2 (3c); IV (C51–C56)P3 (1b, 3b), (C61–C66)P3 (3c); V (C61–C66)P3 (1b, 3b), (C71–C76)P3 (3c); VI (C11–C16)Sn (1b, 3b, 3c); VII
(C11A–C16A)Sn (1b), (C1A–C6A)Sn (3b), (C21–C26)Sn (3c); C [Pd P(1) P(2) P(3) Cl(3)] (1b), [Pt P(1) P(2) P(3) Cl] (3b, 3c); C% [Sn Cl(1) Cl(2)
Cl(1A) Cl(2A)] (1b, 3b), [Sn C(11) C(21) Cl(2)] (3c).
data of palladium and platinum complexes with triphos
are shown in Table 3. The 31P peak for 1 (Table 3) at
109.3 ppm can be assigned to the central phosphorus
(PB) and that at 44.2 ppm to the terminal phosphorus
(PA), on the basis of multiplicity, integration (1:2) and
in comparison with complex 3, the two compounds
being isostructural. The robust square-planar structure
of 3 possesses two equivalent phosphorus donor PPh2
groups, PA, trans to each other (39.8 ppm, 1J(31P–
195Pt)=2484 Hz) and a ‘middle’ phosphorus (PB) cou-
pled to those in cis positions (83.7 ppm,
1J(31P–195Pt)=3015 Hz) (Table 3, Fig. 1). The addition
of one equivalent of SnCl2 to 1 and 3 resulted in the
same complex cations with SnCl−3 as the counterion
(1a, 3a; Scheme 1). Likewise the addition of one and
two equivalents of SnPh2Cl2 to 1 and 3 gave rise to the
compounds which retain the palladium or platinum
square-planar cations and with SnPh2Cl24− (1b, 3b) or
SnPh2Cl−3 (1c, 3c) as the counterions. The PP couplings
of 3.1 Hz for 3 were lower than those found for 1 of 9.4
Hz.
The peaks of the ligand underwent large downfield
shifts (Dl) upon complexation, as was found before for
related chelating ligands [48,49]. For the central phos-
phorus PB of complexes 1a–1c and 3a–3c Dl values
were very large compared to those of the terminal
phosphorus PA. This is due to the participation of PB in
the two fused five-membered chelate rings.
The reaction carried out at the ratio Pt:triphos=3:2
yielded a mixture of ionic and trinuclear covalent com-
plexes (Scheme 2). The 31P NMR spectrum of 3d was
practically identical with that of 3. A novel dinuclear
ionic species 5 has also been characterised by 31P NMR.
Its formation could easily be rationalised by phos-
phino–chloro ligand exchange between the complex
cation and tetrachloroplatinate(II) anion of 3d, result-

864
M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
Fig. 3. ORTEP view and numbering scheme of [Pt(triphos)Cl][SnPh2Cl3] (3c).
Table 3
31P NMR data of complexes 1–6 and titrations
h
Phosphorus
l (ppm)
Dl (ppm) j
1J(31P–195Pt) (Hz)
2J(31P–31P) (Hz)
9.4, 9.4
1 a,b
PA i, PB
PC, PD, PE
PA i, PB
44.2, 109.3
−12.7, 49.9, 54.4
39.8, 83.7
39.6, 83.2
38.4
58.7, 127.5
1.8, 64.4, 72.6
54.3, 101.9
54.1, 101.4
2 c
3 a,b
2484, 3015
2451, 3080
2352
3.1, 3.1
3c a
PA i, PB
4 d
PD,PE
4 e
PC, PD, PE
PF, PG, PH
PF, PG, PJ
PF, PG, PJ
PA i, PB
−15.4, 34.2, 41.5
12.0, 50.6, 44.9
6.2, 52.9, 45.8
−0.9, 48.7, 59.7
26.5, 68.8, 59.4
20.7, 71.1, 60.3
22.4, 70.5, 60.1
2324, 2793
5 f,g
3689, 3557, 3630
3643, ꢀ3560, 3690
3691, ꢀ3560, 3688
56, (56, 2.5), 2.5
57, (57, B2), B2
57, (57, B2), B2
6a g
6b g
7.9, 52.3, 45.6
3+1AgCl a
3c+1Au(I) k
3c+2Au(I) k
3c+3Au(I) k
4+2AgCl d
4+2Au(I) k,l
42.3, 86.3
PA i, PB
39.5, 83.4; 30.0, 41.3, 47.2
39.5, 83.7; 29.8, 41.4, 47.5
39.5, 83.9; 29.8, 41.5, 47.4
44.5, 90.5; 10.7, 13.4
39.5, 83.4; 25.3, 27.6, 29.7
33.0, 48.0, 51.5
31.3, 46.0, 49.5
2451, 3080
2452, 3079
2451, 3075
2471, 3072
2451, 3079
2344
61.3
62.0
PA i, PB
PA i, PB
PA i, PB
PA i, PB
d
4+H2O2
4+H2O2+SnPh2Cl2
m
2331, 2347
a Spectra measured in CDCl3 at room temperature (r.t.).
b 31P NMR spectra of 1a–1c were practically identical with that of 1 and the spectra of 3a, 3b and 3d were very similar to those of 3 and 3c.
c Spectra measured in CD2Cl2 at r.t.
d Spectrum measured in CDCl3+DMSO-d6 at r.t.
e Spectrum measured in CD2Cl2 at 193 K.
f NMR data of the complex anion.
g Spectra measured in DMSO-d6 at r.t.
h For the marking of the phosphorus atoms of triphos see Fig. 1.
i Signal of double intensity (based on integration).
j Dl coordination chemical shift.
k Titration recorded in CDCl3+MeOH at r.t.
l 3J(31P–31P)=48.1 Hz.
m Titration recorded in CDCl3+DMSO-d6+CD2Cl2 at r.t.

M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
865
Table 4
Conductivity measurements carried out with Pt–triphos (PPP) systems
Run Method of preparation
Molar conductivity \ Conductivity s Composition of the complex
(cm2 V−1 mol−1
)
(mS)
mixture (on the basis of 31P
NMR) (%)
3
5
6a+6b
1
2
3
PtCl2(PhCN)2+PPP, benzene reflux, 2 h
8.60
9.85
3.37
34.5 a
39.5 a
13.5 b
100 c
100 d
22 e
0
0
0
0
Run 1, preparation; addition of 1 equiv. SnCl2
3PtCl2(PhCN)2+2PPP, benzene reflux during addition of
PPP; immediate filtration of the product
3PtCl2(PhCN)2+2PPP, benzene reflux during addition of
PPP; filtration of the product after 24 h stirring at r.t.
3PtCl2(PhCN)2+2PPP, benzene reflux for 1 h after
addition of PPP; filtration of the product after 24 h
stirring at r.t.
71 3+4
63 5+7
76 8+10
4
5
3.04
2.34
12.2 b
9.4 b
25 e
6 e
6
Run 5, preparation; benzene reflux, 7 days
0.87
3.5 b
5 e
54 18+23
a Conditions: 0.0500 mmol Pt in 11 ml CH2Cl2.
b The addition of 0.0160 mmol PPP resulted in the same conductivity (s=34.8+0.4 mS).
c Counterion Cl− (3).
d Counterion SnCl−3 (3a).
e Counterion [PtCl4]2− (3d).
ing in a [Pt2(triphos)Cl5]− anion of unprecedented
structure.
Even at higher Pt:triphos ratios (Pt:triphos=3:4 or
higher) complex 3, exhibiting two sharp 1:4:1 patterns,
predominates when tin(II) chloride is also added in
twofold excess. An additional minor broad peak with
detectable platinum satellites was obtained in both
DMSO-d6 and CDCl3 at 44.0 ppm (1J(31P–195Pt)=
2550 Hz) and 44.8 ppm (1J(31P–195Pt):2500 Hz), re-
spectively. However, an extremely broad peak of
double integration value (without any detectable satel-
lites) appeared at around 19 ppm in both cases. In the
absence of tin(II) chloride, a similar situation has been
obtained (lP=37.8 ppm; 1J(31P–195Pt)=2342 Hz).
The appearance of broad peaks can be explained by the
formation of PtP4 species. The less broad peaks can be
assigned to the central phosphorus of triphos coordi-
nated to platinum and the extremely broad peaks refer
to the terminal phosphorus donors in fast exchange
between ring-opened and ring-closed forms [22] of
triphos. Although the broad peak became sharper upon
heating, a signal near to coalescence was not achieved
because of the low solubility of the Pt–triphos system.
Complexes 2 and 4 (Eqs. (3) and (4)) were obtained
as solids via a chelate ring-opening reaction of [M-
(triphos)Cl]+ cations induced by ligand in the presence
of SnPh2Cl2. The 31P NMR spectrum of 2 was in
agreement with the formation of PdP4 complexes show-
ing peaks at 54.4, 49.9 and −12.7 ppm assigned to PE,
PD and PC, respectively (Scheme 1, Fig. 1). A broad
signal between 20 and −10 ppm suggested the ex-
change processes mentioned above. However, the 31P
NMR spectrum of complex 4 in CDCl3+DMSO-d6 at
room temperature showed the only peak at 38.4 ppm,
with a coupling constant of 2352 Hz indicative of P
Two species with very similar NMR characteristics
have been observed upon heating or conducting the
reaction for longer reaction times at room temperature.
The formation of two diastereomers can be explained
as follows. Although the ligand used is achiral, upon
‘asymmetric’ coordination it becomes chiral, since the
two PPh2 groups are bound to two platinum atoms
with different chemical environments. Consequently, in
the case of a two phosphorus stereogenic centre, this
type of coordination resulted in two non-ionic trinu-
clear diastereomers, 6a and 6b (Scheme 2). The cis
geometry for the ‘middle’ platinum has been unequivo-
cally determined for both 6a and 6b. Surprisingly, the
corresponding trans isomer was not detected even in
trace amounts. All of the 1J(31P–195Pt) constants of
diagnostic value were between 3600 and 3700 Hz for
phosphorus trans to the chloro ligand. It has been
clearly demonstrated that the kinetically controlled
ionic product 3d could be transformed into the thermo-
dynamically controlled products 5 and 6a, 6b (Tables 3
and 4). Heating at 70°C for a week resulted in the
predominant formation of these species. It is worth
noting that the mixture of the species isolated as white
solid (run 6, Table 4) was transformed to a mixture of
6a and 6b upon standing in the solid state for a year at
room temperature. All of the Pt:triphos=3:2 mixtures
of covalent and ionic species (runs 3–6) transformed
into 3 upon addition of 0.33 equivalents of triphos in a
very clean facile reaction (Scheme 2), giving rise to the
chelate ring-closure of 5 (complex anion) and 6a, 6b
(neutral diastereomers).

866
M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
and Cl− [53]. This contrasts with dissociation in the
opposite sense proposed by Ouyang et al. for
[SnPh2Cl3]− in [C10H9ON.H.NOH9C10][SnPh2Cl3] sug-
gesting its conversion into [SnPh2Cl4]2− and SnPh2Cl2
[29].
trans to P. Considering the ESMS data, this complex
contained the cation [Pt(triphos)2]2+. The presence of
dangling P atoms was confirmed when the 31P NMR
spectrum of 4 was recorded at low temperatures in
CD2Cl2 (see Fig. 4). At 193 K a splitting (D and E
peaks) of the only signal at 38.4 ppm was detected (34.2
3.4.2. Reacti6ity of [Pt(triphos)Cl]+ (3, 3c) and
[Pt(triphos)2]2+ (4)
1
and 41.5 ppm) with J(31P–195Pt) values of 2324 and
2793 Hz typical of P trans to each other; these were
assigned to PD trans to PD and PE trans to PE, respec-
tively (Fig. 1, Scheme 1). The dangling phosphorus
appeared as a broad peak C in the region of free triphos
(peaks L and M). The 31P spectrum of 4 at 193 K
allowed the proposal of a structure which explains the
ring-opening cation reactions of 3b or 3c described in
Scheme 1 with the formation of the [Pt(triphos)2]2+
cations.
The addition of AgCl to solutions of complex 3 in
CDCl3 followed by 31P NMR showed the absence of
any interaction of Ag(1) with compound 3 (Table 3).
However, when one equivalent of Au(I) was added to
complex 3c a chelate-ring opening reaction occurred
with the formation of the neutral heterobimetallic [23]
complex PtAu(triphos)Cl3 (Eq. (5)).
[Pt(triphos)Cl][SnPh2Cl3]+Au(thiodiglycol)Cl
The 195Pt NMR spectra of compounds 3b and 3c
were, as expected, a doublet of triplets (−4856 and
“PtAu(triphos)Cl3+SnPh2Cl2+thiodiglycol
(5)
1
−4859 ppm, respectively) with J(31P–195Pt) values of
The 31P NMR data (Table 3) showed that besides the
signals due to the complex 3c (even when two or three
equivalents of Au(I) were added) there were three sig-
nals corresponding to the complex PtAu(triphos)Cl3
(l=30.0 (AuPPh2), 41.3 (PtPPh2) and 47.2 (PtPPh)
ppm). This contrasts with the chloro ligand and counter-
ion substitution by nitrate ions when AgNO3 was
added, where the formation of complexes of the type
3053, 2469 (3b) and 3034, 2470 Hz (3c) characteristic of
P trans to Cl and P trans to P, respectively [50–52]. The
195Pt spectrum of 4 showed a multiplet at −5098 ppm
from which coupling constant values were not available.
The 119Sn spectra for compounds 1a and 3a with
trichlorostannato counterion showed a singlet around
−61.0 ppm. The 119Sn chemical shifts for 1c, 2, 3b and
4 were −239.7, −259.1, −177.4 and −256.0 ppm,
respectively, in the expected range for coordination
numbers six (3b) and five (1c, 2, 4) around tin. Although
in the solid state the six coordinate [SnPh2Cl4]2− anion
has been characterised for compound 1b, in solution this
species does not seem to have sufficient Lewis acidity to
allow expansion of the tin coordination from five to six
and the 119Sn NMR spectrum showed a signal at −
253.2 ppm consistent with dissociation into [SnPh2Cl3]−
[M(triphos)(ONO2)]NO3 (M=Pd, Pt) excludes
a
chelate ring-opening reaction [54]. The reaction induced
by gold(I) resulted in a chiral central phosphorus for the
heterobimetallic complex showing a coupling constant
with the terminal phosphorus bound to platinum in the
remaining chelate ring of ca. 60 Hz, which is similar to
that found in complexes 6a, 6b.
The addition of excess Au(I) or AgCl to complex 4
did not produce the formation of any heterometallic
Fig. 4. 31P NMR–{1H} NMR spectra of [Pt(triphos)2][SnPh2Cl3]2 (4) at different temperatures.

M.I. Garc´ıa-Seijo et al. / Polyhedron 20 (2001) 855–868
867
complex of the type [Pt(triphos)2(M%Cl)2][SnPh2Cl3]2
(M%=Au, Ag). In both cases the presence of signals
assigned to the complex 3c with other signals due to
homonuclear complexes [55] with metal to ligand ratios
of 3:1 [l=13.4 ppm (bs) (AgPPh2, AgPPh); 27.6 ppm
(d) (AuPPh2); 29.7 ppm (t) (AuPPh)] and 1:1 [l=10.7
ppm (bs) (AgPPh2, AgPPh) and 25.3 ppm (bs)
(AuPPh2, AuPPh)] were detected. This demonstrates
that the addition of two equivalents of Au(thiodigly-
col)Cl or AgCl to complex 4 was able to produce a
chelate ring-closure reaction by ligand abstraction.
However, the addition of H2O2 to 4 led to the
oxidation of dangling phosphorus and the resulting
phosphine oxide groups seemed to undergo facile reac-
tion with SnPh2Cl2.
Upon addition of triphos to the mixtures, starting
with a Pt:triphos ratio of 3:2 and increasing to a 3:3
ratio (Scheme 2), the conductivity resulted in the same
value as found for complex 3, indicating that a ring-clo-
sure reaction was carried out.
4. Supplementary material
Supplementary data for compounds 1b, 3b and 3c
have been deposited with the Cambridge Crystallo-
graphic Data Centre with deposition numbers CCDC
149833 (1b), CCDC 149834 (3b) and CCDC 149835
(3c). Copies of this information may be obtained free of
charge from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (fax: +44-1223-336033; e-
mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
3.5. Conducti6ity measurements
The molar conductivities for complexes 1a, 1b, 1c,
3a, 3b, 3c, 2 and 4 were obtained in 10−3 M CH3CN
solutions. The values were in agreement with the pres-
ence of 1:1 (1a, 1c, 3a, 3c) and 1:2 (2, 4) electrolytes.
The low value of conductivity for complex 1b (an
expected 2:1 electrolyte), [Pd(triphos)Cl]2[SnPh2Cl4],
showed a very restricted mobility in solution in com-
parison with the analogous Pt complex 3b. This could
be a consequence of dissociation processes in solution
(detected by 119Sn NMR) leading to the formation of
1c.
Acknowledgements
The authors thank the Xunta de Galicia in Spain
(Project XUGA 20906A98 and Predoctoral Grant for
M.I. Garc´ıa Seijo), the Hungarian National Science
Foundation (OTKA T23525) and the Ministry of Edu-
cation (Grant FKFP 0242) for financial support.
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