Influence on reactivity of chloro ligand substitution in mononuclear cationic Pd(II) and Pt(II) triphos complexes: X-ray structure of the nitrate derivatives

Article abstract of DOI:10.1016/S0020-1693(00)00329-7

The substitution of chloro ligand in [M(triphos)Cl]Cl complexes [M = Pd (1), Pt (2); triphos = Ph₂PC₂H₄P(Ph)C₂H₄ PPh₂] by reaction with 1 equiv. of KX resulted in the formation of the ionic complexes [M(triphos)X]Cl [X = I, M = Pd (3), Pt (4); X = CN, M = Pd (5), Pt (6)]. Methanolic solutions of silver nitrate in excess displace the chloro ligand and counterion of 1 and 2, giving rise to the formation of the crystalline complexes [M(triphos)(ONO₂)](NO₃) [M = Pd (7), Pt (8)] suitable for X-ray diffraction studies. The complexes show a distorted square-planar environment around the metal, there being three coordination sites occupied by phosphorus atoms from the triphos and the fourth by the oxygen atom from a nitrate acting as monodentate ligand. A second NO₃^- is acting as counterion with D_3h symmetry. The use of a high excess of SnCl₂ in the presence of 1 equiv. of PPh₃ enabled the formation of complexes [M(triphos)(PPh₃)](SnCl₃)₂ [M = Pd (9), Pt (10)]. These complexes, in addition to [M(triphos)X]X [X = Br, M = Pd (1a), Pt (2a); X = I, M = Pd (1b), Pt (2b)], were synthesised and all Pt(II) complexes characterised by microanalysis. Mass spectrometry, IR spectroscopy, NMR spectroscopy and conductivity measurements were also used for characterisation. The structure and reactivity studies in solution were carried out by ³¹P{¹H} NMR. The trends in chemical shifts δ (P) and ¹J(¹⁹⁵Pt,³¹P) coupling constants were used to establish a sequence in the X ligand exchange reactions. While [Pd(triphos)I]I (1b) undergoes a ring-opening reaction by titration with AuI, the analogous Pt(II) complex (2b) does not react. The formation of new five-coordinate Pd(II) and Pt(II) complexes was observed by titration of 5-8 with potassium cyanide.

Full text of DOI:10.1016/S0020-1693(00)00329-7

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Inorganica Chimica Acta 312 (2001) 40–52
Influence on reactivity of chloro ligand substitution in
mononuclear cationic Pd(II) and Pt(II) triphos complexes: X-ray
structure of the nitrate derivatives
Damia´n Ferna´ndez a, Paloma Sevillano a, M. Ine´s Garc´ıa-Seijo a, Alfonso Castin˜eiras a,
La´szlo´ Ja´nosi b, Zolta´n Berente c,d, La´szlo´ Kolla´r b,d, M. Esther Garc´ıa-Ferna´ndez a,*
a Department of Inorganic Chemistry, Uni6ersity of Santiago de Compostela, A6da. de las Ciencias, E-15706 Santiago de Compostela, Spain
b Department of Inorganic Chemistry, Uni6ersity of Pe´cs, PO Box 266, H-7624 Pe´cs, Hungary
c Institute of Biochemistry, Uni6ersity of Pe´cs, PO Box 99, H-7643 Pe´cs, Hungary
d Research Group for Chemical Sensors of the Hungarian Academy of Sciences, PO Box 266, H-7624 Pe´cs, Hungary
Received 29 May 2000; accepted 20 September 2000
Abstract
The substitution of chloro ligand in [M(triphos)Cl]Cl complexes [M=Pd (1), Pt (2); triphos=Ph2PC2H4P(Ph)C2H4PPh2] by
reaction with 1 equiv. of KX resulted in the formation of the ionic complexes [M(triphos)X]Cl [X=I, M=Pd (3), Pt (4); X=CN,
M=Pd (5), Pt (6)]. Methanolic solutions of silver nitrate in excess displace the chloro ligand and counterion of 1 and 2, giving
rise to the formation of the crystalline complexes [M(triphos)(ONO2)](NO3) [M=Pd (7), Pt (8)] suitable for X-ray diffraction
studies. The complexes show a distorted square-planar environment around the metal, there being three coordination sites
occupied by phosphorus atoms from the triphos and the fourth by the oxygen atom from a nitrate acting as monodentate ligand.
A second NO3− is acting as counterion with D3h symmetry. The use of a high excess of SnCl2 in the presence of 1 equiv. of PPh3
enabled the formation of complexes [M(triphos)(PPh3)](SnCl3)2 [M=Pd (9), Pt (10)]. These complexes, in addition to [M(t-
riphos)X]X [X=Br, M=Pd (1a), Pt (2a); X=I, M=Pd (1b), Pt (2b)], were synthesised and all Pt(II) complexes characterised
by microanalysis. Mass spectrometry, IR spectroscopy, NMR spectroscopy and conductivity measurements were also used for
characterisation. The structure and reactivity studies in solution were carried out by 31P{1H} NMR. The trends in chemical shifts
l (P) and 1J(195Pt, 31P) coupling constants were used to establish a sequence in the X ligand exchange reactions. While
[Pd(triphos)I]I (1b) undergoes a ring-opening reaction by titration with AuI, the analogous Pt(II) complex (2b) does not react. The
formation of new five-coordinate Pd(II) and Pt(II) complexes was observed by titration of 5–8 with potassium cyanide. © 2001
Elsevier Science B.V. All rights reserved.
Keywords: NMR spectroscopy; M(II)–triphos systems; Palladium(II) complexes; Platinum(II) complexes; Monodentate ligand substitutions;
Cyano complexes; Crystal structures
1. Introduction
ligands provide excellent probes to study catalytic hy-
drogenation, substrate displacement reactions or metal-
induced activation of small molecules. Likewise, it has
been shown that complexes [2] containing a tridentate
triphosphine, such as [Pd(tridentate)(CH3CN)][BF4]2,
catalyse the electrochemical reduction of CO2 to CO in
acidic dimethylformamide or acetonitrile solutions if
the tridentate phosphine is a linear triphosphine ligand.
The metallic systems with a linear tridentate triphos-
phine probe the trans influence of a variety of ligands
upon the central phosphorus–metal bond. The chelat-
The chelate effect of polyphosphine ligands reduces
complications in studies of catalytic properties of the
metal complexes by eliminating the substitutions equi-
libria of labile monodentate phosphine ligands [1].
Metal complexes with linear tridentate triphosphine
* Corresponding author. Tel.: +34-981-563100/14241; fax: +34-
981-597525.
E-mail address: qiegfq@usc.es (M.E. Garc´ıa-Ferna´ndez).
0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0020-1693(00)00329-7

D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
41
2. Experimental
ing nature of the phosphine ensures that the ligand field
about the metal in [M(tridentate)X]n+ complexes is
enforced, maintaining the same geometrical configura-
tion for a series of different ligands X.
2.1. General procedures and instrumentation
The linear triphosphine Ph2PC2H4P(Ph)C2H4PPh2
(triphos) is one of the tritertiary phosphines that forms
square-planar cationic complexes with Pd(II) or Pt(II)
acting as the tridentate chelating ligand [2], the fourth
coordination position being occupied by another
monodentate ligand.
Solvents were dried by conventional methods, dis-
tilled and kept under argon. Other reagents were avail-
able of the highest commercial grade and were used as
received. Solvent evaporations were always carried out
under vacuum using a rotary evaporator and a vacuum
line. Microanalyses (C, H, N) were performed at the
Universities of Santiago de Compostela and Pe´cs. Fast
atom bombardment (FAB) spectra were obtained on a
KRATOS MS 50 spectrometer using 3-nitrobenzyl al-
cohol as the matrix. Infrared spectra were recorded at
There are some reports concerning the structure of
these Pd(II)–triphos and Pt(II)–triphos systems. The
solid state structure of [Pd(triphos)(F6-acac)](F6-acac)
(F6-acac=hexafluoroacetylacetonate) was reported by
Siedle and Newmark [3] in 1981; they demonstrated
using 19F NMR studies that there is a facile exchange
between ionic and coordinated F6-acac. 195Pt NMR
data [4] obtained for [Pt(triphos)Cl][BF4] and [Pt(t-
riphos)Br]Br were consistent with a distorted square-
planar arrangement around platinum. The same
disposition was found in solution [5] for complex [Pt(t-
riphos)I]X (X=dithiolate). The crystal structure of
[Pd(triphos)Cl]Cl was reported [6] in 1990, and the first
crystal structure for a Pt(II) compound containing this
potentially tridentate phosphine, triphos, corresponded
to [Pt(triphos)(dtc)][BPh4] (dtc=S2CNEt2) reported by
Colton et. al. [7] in 1993.
However, little is known about the comparative reac-
tivities of Pd(II) and Pt(II) complexes, especially the
chloro ligand substitutions and their influence on subse-
quent reactions. We have previously described [8,9]
ring-opening reactions of the robust square-planar
structure of these [M(triphos)X]X (M=Pd, Pt, X=
Cl; M=Pd, X=Br) complexes containing two fused
five-membered rings. Thus the coordinated triphos in
[Pd(triphos)Br]Br undergoes facile oxidation [8] by the
action of oxidising agents leading to the formation of
square-planar or five-coordinate square-pyramidal
cationic Pd(II) complexes containing two phosphine
monoxide pendant arms. Although Pt(II)–triphos com-
plexes exhibit higher thermodynamic stability and
higher kinetic inertness than those of Pd(II), both
late transition metal ions, under the formation of
chloro complexes, react with Au(I) to afford com-
pounds that combine square-planar Pd(II) or Pt(II)
and linear Au(I) centres. Since reactivity can be de-
signed by the choice of an adequate substituent ligand
trans to the central phosphorus of triphos [9,10], in
this study we describe the synthesis and the structural
and chemical characterisation of a series of complexes
afforded by substitution of the chloro ligand in the
parent compounds [M(triphos)Cl]Cl, M=Pd, Pt, with
formation of new MꢀBr, MꢀI, MꢀC, MꢀO or MꢀP
bonds.
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; w, weak; sh,
shoulder. 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 MHz 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 (ppm);
s, singlet; d, doublet; t, triplet; dt, doublet of triplets; m,
multiplet; bs, broad signal; J is the coupling constant
(Hz). Conductivities were obtained at 25°C from
10−3 M solutions in DMF or CH3CN on a WTW
model LF-3 instrument.
2.2. X-ray structure determinations
Colourless prismatic crystals of 7 and 8 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 of
8.587BqB13.876° (7) and 8.747BqB17.995° (8) in
an Enraf–Nonius MACH3 automatic diffractometer
[11]. Data were collected at 293 K using Mo Ka radia-
,
tion (u=0.71073 A) and the ꢀ scan technique and
corrected for Lorentz and polarization effects [12]. A
semi-empirical absorption correction (c scan) was
made [13].
The structures were solved by direct methods [14],
which revealed the position of all non-hydrogen
atoms, and refined on F2 by a full-matrix least-squares
procedure using anisotropic displacement parameters
[15]. Atomic scattering factors were obtained with the
use of International Tables for X-ray Crystallography
[16]. Molecular graphics were obtained from ZORTEP
[17].

42
D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
2.3. Preparations
2.3.1. [Pd(triphos)X]X
ing yellow solution of PtCl2(PhCN)2 (0.4720 g,
1.0000 mmol) in benzene (45 ml). After a few minutes a
fine white precipitate was formed. The mixture was
stirred for 1 h, then cooled to room temperature. The
solid was filtered off, washed with benzene, and dried
under reduced pressure to give [Pt(triphos)Cl]Cl as a
white powder. Yield: 91%; m.p. 200°C. Anal. Found: C,
51.18; H, 4.33. Calc. for C34H33Cl2P3Pt: C, 51.01; H,
2.3.1.1. X=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 then 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 and
the solvent removed in vacuo to leave a white solid.
The solid was filtered off, washed with water, dried in
vacuo and recrystallised from CH2Cl2–n-hexane, to
give colourless prisms. Yield: 67%;, m.p. \250°C.
Anal. Found: C, 57.01; H, 4.90. Calc. for
C34H33Cl2P3Pd: C, 57.31; H, 4.67%. 31P{1H} NMR
(CDCl3): l 44.2 (d) [PA], 109.3 (t) [PB], (2J(PB, PA)=
9.4 Hz). IR wmax/cm−1: (PdꢀCl) 318vs. m/z (FAB): 675
(M+−Cl−, 100%). \ (V−1 cm2 mol−1, DMF): 91.5.
4.15%. 31P{1H} NMR (CDCl3):
l
39.8 (s) [PA,
1J(195Pt, 31P)=2484 Hz; 2J(PB, PA)=3.1 Hz], 83.7 (s)
1
[PB, J(195Pt, 31P)=3015 Hz]. 195Pt NMR (CDCl3): −
4858.3
(dt)
[PB,
1J(195Pt, 31P)=3015 Hz;
PA,
1J(195Pt, 31P)=2484 Hz]. IR wmax/cm−1: (PtꢀCl) 320vs,
314sh. m/z (FAB): 764 (M+−Cl−, 100%).
(V−1 cm2 mol−1, DMF): 82.9.
\
2.3.2.2. X=Br (2a). The procedure followed was ex-
actly the same than in method 1 (Section 2.3.2.1) except
that K2PtBr4 was used instead of K2PtCl4. Yield: 51%;
m.p. 205°C. Anal. Found: C, 45.64; H, 3.92. Calc. for
C34H33Br2P3Pt: C, 45.90; H, 3.73%. 31P{1H} NMR
1
2.3.1.2. X=Br (1a). The complex was obtained simi-
larly by a metathesis reaction upon addition of sodium
bromide to 1 in molar ratio of 2:1. Yield: 80%; m.p.\
178°C. Anal. Found: C, 51.14; H, 4.25. Calc. for
C34H33Br2P3Pd: C, 50.91; H, 4.12%. 31P{1H} NMR
(CDCl3):, l 45.0 (d) [PA], 110.4 (t) [PB] (2J(PB, PA)=
8.2 Hz). IR wmax/cm−1: (PdꢀBr) 207s. m/z (FAB): 724
(M+−Br−, 100%). \ (V−1 cm2 mol−1, DMF): 69.6.
(CDCl3): l 40.2 (s) [PA, J(195Pt, 31P)=2464 Hz], 86.7
1
(s) [PB, J(195Pt, 31P)=2992 Hz]. 195Pt NMR (CDCl3):
1
1
-5004.0 (dt) [PB, J(195Pt, 31P)=2992 Hz; PA, J(195Pt,
31P)=2464 Hz]. IR wmax/cm−1: (PtꢀBr) 231vs, 216vs.
m/z
(FAB):
808
(M+−Br−,
100%).
\
(V−1 cm2 mol−1, DMF): 82.0.
2.3.2.3. X=I (2b). The preparation was identical to
that for 1b except that KI was added to an aqueous
solution of K2PtCl4. Yield: 42%; m.p. 165°C. Anal.
Found: C, 41.44; H, 3.41. Calc. for C34H33I2P3Pt: C,
41.52; H, 3.40%. 31P{1H} NMR (CDCl3): l 40.1 (s) [PA,
1J(195Pt, 31P)=2424 Hz], 89.9 (s) [PB, 1J(195Pt, 31P)=
2895 Hz]. 195Pt NMR (CDCl3): −5256.0 (dt) [PB,
1J(195Pt, 31P)=2895 Hz; PA, 1J(195Pt, 31Pt)=2424 Hz].
IR wmax/cm−1: (PtꢀI) 172w. m/z (FAB): 856 (M+−I−,
100%). \ (V−1 cm2 mol−1, DMF): 85.0.
2.3.1.3. X=I (1b). A solution of NaI (4.5249 mol
equiv.) in H2O was added to the cool solution of
Na2PdCl4 and the mixture was stirred for 2 h under
nitrogen. Triphos (1.0000 mol equiv.) and EtOH were
added and the solution was refluxed for 5 h. This was
left to cool to room temperature and a yellow solid
precipitated. The solid was filtered off and dried in
vacuo. Yield: 93%; m.p. \165°C (dec.). Anal. Found:
C, 45.70; H, 3.70. Calc. for C34H33I2P3Pd: C, 45.61; H,
3.70%. 31P{1H} NMR (CDCl3): l 45.4 (d) [PA], 109.5
(t) [PB] (2J(PB, PA)=6.5 Hz). IR wmax/cm−1: (PdꢀI)
2.3.3. [Pd(triphos)I]Cl (3)
The
[Pd(triphos)Cl]Cl
complex
(0.0976 g,
172w. m/z (FAB): 765 (M+−I−, 100%).
(V−1 cm2 mol−1, DMF): 88.2.
\
0.1371 mmol) was added to a solution of KI (0.0228 g,
0.1371 mmol) dissolved in methanol (10 ml). The solu-
tion was kept at 50°C with constant stirring for 15 h.
Ether was added (80 ml) and the yellow powder-like
material was filtered off, washed with water and ether,
then left to dry. Yield: 49%. Anal. Found: C, 49.97; H,
4.09. Calc. for C34H33CIP3Pd: C, 50.79; H, 4.11%.
31P{1H} NMR (CDCl3): l 45.6 (s) [PA]; 110.3 (s) [PB].
2.3.2. [Pt(triphos)X]X
2.3.2.1. X=Cl (2). Method 1: 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 solvent 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 reflux-
m/z
(FAB):
765
(M+−Cl−,
100%).
\
(V−1 cm2 mol−1, DMF): 67.0.
2.3.4. [Pt(triphos)I]Cl (4)
The [Pt(triphos)Cl]Cl complex (0.4002 g, 0.5000
mmol) was added to a solution of KI (0.0830 g, 0.5000
mmol) dissolved in methanol (10 ml). The power did

D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
43
not dissolve completely but was kept in suspension at
1281s. m/z (FAB): 747 (M+−O, 100%).
(V−1 cm2 mol−1, DMF): 91.1.
\
50°C with constant stirring for 20 h. The pale yellow
powder-like material was filtered off, washed with wa-
ter, methanol and ether, then left to dry. Recrystallisa-
tion was carried out in a benzene–methanol mixture.
Yield: 75%. Anal. Found: C, 45.97; H, 3.89. Calc. for
C34H33ClIP3Pt: C, 45.78; H, 3.73%. 31P{1H} NMR
2.3.8. [Pt(triphos)(ONO2)](NO3) (8)
A solution of AgNO3 (0.0424 g, 0.2509 mmol) in
MeOH (10 ml) was added dropwise to a solution of 2
(0.1000 g, 0.1249 mmol) in CHCl3 (10 ml). A white
precipitate of AgCl was filtered off. Solvents were re-
moved in vacuo and the solid was recrystallised from
CH2Cl2–n-hexane. Crystals suitable for X-ray diffrac-
tion were obtained. Yield: 85%; m.p. 270°C. Anal.
Found: C, 47.44; H, 4.00; N, 3.32. Calc. for
C34H33N2O6P3Pt: C, 47.83; H, 3.90; N, 3.32%. 31P{1H}
(CDCl3):
l
42.6 (d) [PA, 1J(195Pt, 31P)=2425 Hz,
2J(PB, PA)=1.7 Hz]; 92.5 (t) [PB, 1J(195Pt, 31P)=
2890 Hz, J(PB, PA)=1.7 Hz]. m/z (FAB): 856 (M+−
2
Cl−, 100%). \ (V−1 cm2 mol−1, DMF): 80.2.
2.3.5. [Pd(triphos)(CN)]Cl (5)
1
NMR (CDCl3): l 43.4 (s) [PA, J(195Pt, 31P)=2596 Hz,
The [Pd(triphos)Cl]Cl complex (0.1055 g, 0.1482
mmol) was added to a solution of potassium cyanide
(KCN) (0.0097 g, 0.1482 mmol) dissolved in methanol
(12 ml). The solution was kept at 50°C with constant
stirring for 5 h. Ether was added (80 ml) and the white
powder-like material was filtered off, washed with wa-
ter and ether, then left to dry. Yield: 90%; m.p. 182°C.
Anal. Found: C, 58.45; H, 5.02; N, 1.82. Calc. for
C35H33ClNP3Pd: C, 59.79; H, 4.70; N, 1.99%. 31P{1H}
NMR (CDCl3): l 47.9 (s) [PA]; 106.0 (s) [PB]. m/z
2J(PB, PA)=8.5 Hz]; 73.9 (s) [PB, 1J(195Pt, 31P)=
3255 Hz, 2J(PB, PA)=8.5 Hz]. IR wmax/cm−1
(NꢀO)nitrate 1370vs, 830m; (NꢀO)coordinate 1486vs,
1274vs, 991s. m/z (FAB): 837 (M+−O, 100%). \
(V−1 cm2 mol−1, DMF): 101.8.
2.3.9. [Pd(triphos)(PPh3)](SnCl3)2 (9)
The [Pd(triphos)Cl]Cl complex (0.1011 g, 0.1420
mmol), was dissolved in CH2Cl2 (12 ml) under nitrogen.
Triphenylphosphine (PPh3) (0.0410 g, 0.1562 mmol)
and tin(II) chloride (SnCl2) (0.2693 g, 1.4200 mmol)
were added and stirred for 7 h. The white solid formed
was filtered off, washed with CH2Cl2, then left to dry.
31P{1H} NMR (CD3OD+CH2Cl2): l 19.3 (s) [PPh3];
(FAB): 666 (M+−Cl−, 100%). \ (V−1 cm2 mol−1
CH3CN): 130.5.
,
2.3.6. [Pt(triphos)(CN)]Cl (6)
The [Pt(triphos)Cl]Cl complex (0.4002 g, 0.5000
mmol) was added to a solution of potassium cyanide
(KCN) (0.0325 g, 0.5000 mmol) dissolved in methanol
(10 ml). The powder did not dissolve completely but
was kept in suspension at 50°C with constant stirring
for 10 h. The white powder-like crystals were filtered
off, washed with water, methanol and ether, then left to
dry. Recrystallisation was carried out in a benzene–
methanol mixture. Yield: 80%. Anal. Found: C, 53.33;
H, 4.38; N, 2.02. Calc. for C35H33ClNP3Pt: C, 53.14; H,
4.20; N, 1.77%. 31P{1H} NMR (CDCl3): l 41.0 (d) [PA,
1J(195Pt, 31P)=2383 Hz, 2J(PB, PA)=6.0 Hz]; 90.8 (t)
2
48.4 (d) [PA, J(31P, 31P)=8.5 Hz]; 112.6 (s) [PB].
2.3.10. [Pt(triphos)(PPh3)](SnCl3)2 (10)
The [Pt(triphos)Cl]Cl complex (0.4002 g, 0.5000
mmol) was dissolved in CH2Cl2 (25 ml) under argon.
Triphenylphosphine (PPh3) (0.1441 g, 0.5500 mmol)
and tin(II) chloride (SnCl2) (0.9495 g, 5.0000 mmol)
were added and stirred for 5 h. The unreacted tin(II)
chloride was filtered off, then the solution was evapo-
rated to 10 ml and 1 ml of n-hexane was added. A
white powder-like substance was formed. Yield: 68%.
Anal. Found: C, 43.55; H, 3.52. Calc. for C52H48Cl6-
P4PtSn2: C, 43.31; H, 3.36%. 31P{1H} NMR (CDCl3): l
1
2
[PB, J(195Pt, 31P)=2205 Hz, J(PB, PA)=6.0 Hz]. m/z
(FAB): 755 (M+−Cl−, 100%). \ (V−1 cm2 mol−1
DMF): 81.0.
,
1
2
14.2 (dt) [PPh3, J(195Pt, 31P)=2542 Hz, J(31P, 31P)=
294.0, 21.7 Hz]; 45.1 (d) [PA, J(195Pt, 31P)=2381 Hz,
1
2J(31P, 31P)=21.7 Hz]; 93.4 (d) [PB, 1J(195Pt, 31P)=
2.3.7. [Pd(triphos)(ONO2)](NO3) (7)
2112 Hz, J(31P, 31P)=294.0 Hz]. m/z (FAB): 990 (M+
2
To
a
solution of [Pd(triphos)Cl]Cl (0.1000 g,
−2SnCl3−, 100%). \ (V−1 cm2 mol−1, DMF): 97.1.
2.4. Titrations
0.1400 mmol) in CHCl3 (15 ml), a solution of AgNO3
(0.0525 g, 0.3106 mmol) in MeOH (15 ml) was added
dropwise. A white precipitate of AgCl was filtered off.
Solvents were removed in vacuo and the solid was
recrystallised from CH2Cl2–n-hexane. Suitable crystals
for X-ray diffraction were obtained. Yield: 77%; m.p.
235°C. Anal. Found: C, 56.30; H, 4.50; N, 3.80. Calc.
for C34H33N2O6P3Pd: C, 56.90; H, 4.60; N, 3.90%.
2.4.1. With Au(I)
(a) Solutions of Au(tdg)X (X=Cl, Br) 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 (thiodiglycol=tdg) as indicated in
the literature [18–20]. To solutions of the complexes
[Pt(triphos)Br]Br (2a), [M(triphos)(CN)]Cl [M=Pd (5),
Pt (6)], [M(triphos)(ONO2)](NO3) [M=Pd (7), Pt (8)]
2
31P{1H} NMR (CDCl3): l 47.4 (d) [PA, J(1PB, PA)=
8.5 Hz]; 109.3 (t) [PB, 2J(PB, PA)=9.2 Hz]. IR wmax
/
cm−1 (NꢀO)nitrate 1384vs, 831m; (NꢀO)coordinate 1465vs,

44
D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
and [Pt(triphos)(PPh3)](SnCl3)2 (10), in the solvents
shown in Table 4, solutions of Au(I) in MeOH in
different stoichiometric ratios were added. After 12 h
the 31P{1H} NMR spectra were recorded.
(b) To solutions of the complexes [M(triphos)I]I
[M=Pd (1b), Pt (2b) and [M(triphos)I]Cl [M=Pd (3),
Pt (4)], in the solvents shown in Table 4, AuI was added
as a solid in different stoichiometric ratios. The mixture
was stirred for 12 h and the unreacted AuI was filtered
off, then the 31P{1H} NMR spectra were recorded.
2.4.2. With KX (X=I, CN)
Scheme 1. The formation of ionic chloro ligand substitution com-
plexes.
To solutions of the complexes [M(triphos)(CN)]Cl
[M=Pd (5), Pt (6)], [M(triphos)(ONO2)](NO3) [M=Pd
(7), Pt (8)] and [Pt(triphos)(PPh3)](SnCl3)2 (10), in the
solvents shown in Table 5, solutions of KI or KCN in
MeOH were added, in different stoichiometric ratios.
After 12 h the 31P{1H} NMR spectra were recorded.
2.4.3. With PPh3
To solutions of the complexes [M(triphos)-
(ONO2)](NO3) [M=Pd (7), Pt (8)] in MeOH+CHCl3,
solutions of PPh3 in CDCl3 were added, in different
molar ratios. 31P{1H} NMR spectra were recorded after
each addition.
3. Results and discussion
3.1. Preparations
Complexes 1 and 2 were obtained from aqueous
solutions of MCl42− (M=Pd, Pt) by reaction with the
ligand triphos in dichloromethane and affording the
complexes from the organic phase [9,21,22]. By dis-
placement of the chloro ligand and counterion in 1 or 2
with KBr and KI the complexes 1a, 2a and 1b, 2b
respectively can be afforded (Scheme 1). Using only
1 equiv. of KI or KCN the substitution of the chloro
ligand by I− or CN− was observed in complexes 3, 4 or
5, 6 respectively.
The addition of 2 equiv. of silver nitrate to solutions
of 1 and 2 produced the substitution of both chloro
ligand and counterion by the NO3− anion, obtaining
the complexes 7 and 8.
When tin(II) chloride (SnCl2) was added to 1 and 2
in tenfold excess in the presence of 1 equiv. of PPh3,
complexes 9 and 10 were formed.
3.2. Crystallography
The ORTEP diagrams with numbering schemes for
complexes 7 and 8 are shown in Fig. 1. Crystal parame-
ters, data collection and refinement for the crystal
structures are given in Table 1. Selected bond distances
and angles for 7 and 8 compared with those of 1 and 2
are listed in Table 2. The complexes consist of a cation
Fig. 1. ORTEP view and numbering scheme of [Pd(triphos)(ONO2)]-
(NO3) (7) and [Pt(triphos)(ONO2)](NO3) (8).

D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
45
Table 1
,
are longer [2.199(5) and 2.214(5) A] than the NiꢀPcentral
Crystallographic data for compounds 7 and 8
,
bond [2.111(5) A]. The presence of an oxygen trans to
the central phosphorus resulted in the shortest MꢀP(2)
bond distance compared with compounds 1 (M=Pd)
and 2 (M=Pt).
Complex
7
8
Empirical formula
Formula weight
Temperature (K)
Wavelength (A)
Crystal size (mm)
Colour/habit
C34H33N2O6P3Pd
764.93
293(2)
0.71073
0.25×0.20×0.15
Colourless/prisms Colourless/prisms
Triclinic Triclinic
P1
10.570(2)
12.397(3)
13.192(7)
88.16(2)
78.38(2)
86.80(2)
1690.1(1)
2
C
853.62
293(2)
0.71073
34H33N2O6P3Pt
,
The MꢀO bond lengths, 2.127(4) A (7) and
,
2.118(4) A (8) were as expected, in spite of the incom-
,
patibility of the ‘hard’ basic ligand and the ‘soft’ metal
centres [24–26]. Whereas the PtꢀO bond distance was
slightly shorter than the PdꢀO length, both MꢀO dis-
0.25×0.25×0.15
Crystal system
Space group
(
(
P1
,
tances were significantly longer (approximately 0.2 A)
,
a (A)
10.664(1)
12.375(2)
13.179(1)
87.79(9)
77.53(9)
86.92(1)
1695.1(4)
2
than the NiꢀO bond length in the above-mentioned
,
b (A)
,
Ni(II) [27] complex [1.937(11) A].
,
c (A)
h (°)
i (°)
k (°)
Volume (A )
Z
The PꢀMꢀP angles 82.15(5), 84.30(5), 163.11(5)°
(M=Pd) and 83.14(6), 85.34(5), 164.68(5)° (M=Pt) as
well as the PꢀMꢀO angles, 94.07(1), 97.75(1), 171.04(1)°
(M=Pd) and 92.49(1), 97.47(1), 171.64 (1)° (M=Pt)
revealed the distorted square-planar geometry.
3
,
Calculated density
1.503
1.672
(Mg m−3
)
The nitrato ligand bound to M retains the trigonal
planar geometry, with OꢀNꢀO angles very close to
120°. However, the NꢀO distances corresponding to the
Absorption
0.738
4.327
coefficient
(mm−1
F(000)
q range for data
collection (°)
)
,
oxygen bound to the metal, 1.265(5) A (M=Pd) and
780
2.30 to 30.41
844
2.24 to 26.30
,
1.305(6) A (M=Pt), are longer than the NꢀO distances
corresponding to uncoordinated oxygen atoms. This is
a consequence of the decrease in the nitrogen–oxygen
bond order.
Index ranges
05h515,
−175k517,
−185l518
−125h513,
−155k515, 05l516
Reflections collected 10 731
7179
6870
(Rint=0.0332)
Semi empirical
The phenyl ring planes (I–V) of the cation, in addi-
tion to the best coordination plane at the metal (C) and
the planes of the bound nitrate (C%) and counterion
(C¦), are defined in Table 2. In both cases the dihedral
angle C–C% [74.47 (7), 70.38° (8)] shows an arrange-
ment neighbouring to perpendicularity, minimising the
bulky hindrance of phenyl substituents on P(1) and
P(3). The dihedral angle C%–C¦ [29.53 (7), 28.11° (8)]
reveals that the planes corresponding to the nitrate
ligand and counterion are closer to coplanarity than
perpendicularity.
Independent
reflections
Absorption
correction
10 221
(Rint=0.0622)
Semi empirical
Max. and min.
transmission
Data/restraints/
parameters
0.964 and 0.900
10 221/0/416
0.933
0.981 and 0.785
6870/0/547
1.036
Goodness of fit on
F2
Final R indicesa
R1=0.0568,
wR2=0.0929
R1=0.0346,
wR2=0.0630
Largest diff. peak
0.523 and −1.408 0.699 and −1.076
,
,
The M atom departs from C [0.196 A (7), 0.187 A
and hole
,
(8)] compared with the mean values of 0.028 A (7) and
−3
(e−
)
,
A
,
0.032 A (8) for atoms defining the plane. The phenyl
a I\2|(I).
substituents on P(1) and P(3) form dihedral angles I–II
[76.08 (7), 79.66° (8)] and IV–V [77.63 (7), 78.20° (8)]
respectively that are very similar. The phenyl ring on
P(2) forms angles III–C of 86.95° (7) and 87.01° (8)
that are also consistent with perpendicularity with re-
spect to the best coordination plane C.
The inter- and intra-ionic interactions due to the
presence of weak H-bonds determine the dynamics of
these structures. The higher electronegativity of oxygen
compared with the chloro atom led to stronger H-
bonds with respect to complexes 1 and 2. In fact the
with distorted square-planar geometry for the metal
where triphos is acting as tridentate chelate ligand and
a nitrato acting as a monodentate ligand. Another
nitrate anion is the counterion. The MꢀP distances,
,
2.319(2) [P(1)], 2.210(2) [P(2)], 2.343(2) A [P(3)] for
complex and 2.321(2) [P(1)], 2.207(2) [P(2)],
7
,
2.313(2) A [P(3)] for complex 8 are in the expected
range. The MꢀP(2) bond lengths were shorter than the
other MꢀPterminal distances due to the participation of
the central phosphorus in two fused five-membered
rings. Likewise for the analogous Ni(II) complex [Ni-
(triphos)OS(O)CH3]+, the two NiꢀPterminal bonds [23]
,
H···O intracationic interactions were 2.4894 A (7) and
,
,
2.4086 A (8) [versus 2.915(9) A for complex 2] [9] with
CꢀH···O angles of 162.53° (7) and 158.18° (8). The
interionic H···O contacts (cation–anion) were approxi-

46
D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
,
,
mately 2.5000 A (7) and 2.4000 A (8) with CꢀH···O
3.4. NMR spectra
angles around 150.00° (7) and 160.00° (8).
,
The M···M distances higher than 9.0000 A showed
the absence of metal–metal interactions.
3.4.1. Complexes 1–10
The 31P NMR data for compounds 1, 1a, 1b, 2, 2a,
2b and 3–9 were consistent with the presence of
cationic square-planar four-coordinate complexes [M-
(triphos)X]+. Table 3 shows the NMR data for platinum
complexes arranged in the order of decreasing central
phosphorus–platinum coupling constants. Except for
compounds 6 and 10, in all cases these coupling
3.3. Conducti6ities, FAB mass and infrared spectra
The conductivity measurements for 10−3 M solutions
of 1, 1a, 1b, 2, 2a, 2b, 3, 4, 5, 6, 7, 8 and 10 were
consistent [27] with the presence of 1:1 electrolytes.
The FAB mass spectra of complexes 1, 1a, 1b, 3, 5
and 2, 2a, 2b, 4, 6, 10 in all cases showed a peak with
100% abundance due to the loss of the counteranion.
However, for complexes 7 and 8 the most abundant
peak corresponded to the loss of an oxygen of one
NO3− ion (M+−O, 100%).
1
1
constants J(195Pt, 31PB) are higher than J(195Pt, 31PA)
(seeScheme2forlabelledatoms)and follow the sequence:
NO−3 \Cl−\Br−\I−\CN−\PPh3.
By substitution of the chloro ligand by I− in com-
plexes 1 and 2 the compounds 3 and 4 respectively were
afforded. Unlike the formation of [Pt(triphos)I]Cl (4),
chloro–iodo ligand exchange did not take place even in
traces upon addition of SnI2. On the basis of earlier
findings [29], the insertion of SnI2 into the PtꢀCl bond
of 2 can be excluded because, according to the sup-
posed mechanism of the ligand exchange, the soft iodo
ligand should bind to the soft metal centre Pt(II) while
the tin(II) chloride (SnCl2) dissociates.
The far IR spectra (500–100 cm−1) for complexes 1,
1a, 1b, 2, 2a and 2b showed bands assigned in accor-
dance with the literature [9,11,28], to MꢀX stretchings
corresponding to terminal bonds. The w(NꢀO) for com-
plexes 7 and 8 were in agreement with the presence of
nitrate as ligand and counterion.
Table 2
,
Selected distances (A) and angles (°) for compounds 1, 2, 7 and 8
1a [Pd(triphos)Cl]Cl
7 [Pd(triphos)(ONO2)](NO3)
2b [Pt(triphos)Cl]Cl
8 [Pt(triphos)(ONO2)](NO3)
PꢀM
2.220(2)
2.328(2)
2.344(2)
2.355(2)
2.209(2)
2.319(2)
2.343(2)
2.207(2)
2.312(2)
2.315(2)
2.349(2)
2.207(2)
2.313(2)
2.321(2)
MꢀCl
MꢀO
NꢀOc
2.127(4)
1.216(6)
1.245(5)
1.265(5)
2.118(4)
1.215(7)
1.222(6)
1.305(6)
PꢀMꢀP
PꢀMꢀCl
PꢀMꢀO
OꢀNꢀOc
83.80(1)
84.10(1)
167.80(1)
93.60(1)
98.50(1)
176.40(1)
82.15(5)
84.30(5)
163.11(5)
84.69(7)
84.92(7)
169.54(6)
92.94(7)
97.50(7)
176.52(7)
83.14(6)
85.34(5)
164.68(5)
94.07(1)
97.75(1)
171.04(1)
117.60(5)
119.80(5)
122.60(5)
76.08
86.95
77.63
74.47
29.53
92.49(1)
97.47(1)
171.64(1)
117.30(5)
118.10(5)
124.50(6)
79.66
87.01
78.20
70.38
28.11
I–IId
73.15
83.20
88.08
72.73
83.24
88.16
III–Cd
IV–Vd
C–C%d
C%–C¦d
a See Ref. [6].
b See Ref. [9].
c NꢀO distances and OꢀNꢀO angles correspond to nitrate as ligand.
d Angles between planes defined as: I (C11ꢀC16)P1; II (C21ꢀC26)P1; III (C31ꢀC36)P2; IV (C41ꢀC46)P3; V (C51ꢀC56)P3; C [Pd P(1) P(2) P(3)
Cl] (1),[Pd P(1) P(2) P(3) O] (7),[Pt P(1) P(2) P(3) Cl] (2),[Pt P(1) P(2) P(3) O] (8), C% [N(1) O(11) O(12) O(13)] (7, 8), C¦ [N(2) O(21) O(22) O(23)]
(7, 8).

D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
47
Table 3
NMR data for platinum complexes in CDCl3
Phosphorusa
l (ppm)
lPt (ppm)
1J(195Pt, 31P) (Hz)
2J(31P, 31P) (Hz)
8
2
2a
2b
4
PAb, PB
43.4, 73.9
39.8, 83.7
40.2, 86.7
40.1, 89.9
42.6, 92.5
41.0, 90.8
14.2, 45.1, 93.4
2596, 3255
2484, 3015
2464, 2992
2424, 2895
2425, 2890
2383, 2205
2542, 2381, 2112
9.2, 9.2
3.1, 3.1
PAb, PB
−4858
−5004
−5256
PAb, PB
PAb, PB
PAb, PB
1.7, 1.7
6.0, 6.0
(294.0, 21.7), 21.7, 294.0
6
10
PAb, PB
PPh3, PAb, PB
a Phosphorus atoms of triphos are labelled in Scheme 2.
b Double integration compared with PB.
Scheme 2. Ring-opening reactions of [M(triphos)X]+ (M=Pd, Pt; X=I, Br, CN) complexes with AuI or Au(tdg)Cl.
glutathione, N-acetyl-
L
-cysteine or N-acetyl-
L
-methion-
The parent ionic complexes 1 and 2 also underwent
ine), complex 8, prepared in situ by addition of AgNO3
in excess to 2, produced interaction with thiols with
formation of PtꢀS bonds.
facile exchange reactions in the presence of KCN giving
1
rise to complexes 5 and 6. The J(195Pt, 31P) coupling
constant (2205 Hz) corresponding to PB trans to C of
the cyano group of 6 decreased 810 Hz compared with
the coupling constant assigned to PB trans to Cl in the
parent complex 2. This coupling constant is also lower
than those found for other cyanide complexes of the
The addition of PPh3 and tin(II) chloride in tenfold
excess to 1 and 2 led to the formation of complexes 9
and 10 respectively. In both cases the appearance of a
PtP4 system was detected. The triphenylphosphine
phosphorus coordinates to Pt in trans position to PB.
All 1J(195Pt, 31P) constants, as expected, were in the
range 2110–2550 Hz characteristic of P trans to P, with
the highest value due to the coupling constant PtꢀP
(PPh3). Although the formation of [Pt(triphos)-
(SnCl3)](SnCl3) complex was not detected by NMR, it
might be present in small quantities and the facile
substitution of the good trichlorostannate leaving
group with triphenylphospine might take place. Like-
wise, the formation of [Pd(triphos)(SnCl3)](SnCl3)
should not be excluded; the 119Sn NMR spectrum cor-
responding to a solution in dmso-d6 of the solid ob-
tained from a mixture of the reaction between 1, PPh3
and SnCl2 showed two broad signals at −360 and
−252 ppm that could be assigned to SnCl2 in excess
and the PdꢀSn bond in the complex respectively. The
signal at −252 ppm was not detected when the 119Sn
type
[Pt(phosphine)(CN)2]
[phosphine=1,3-bis-
(diphenylphosphino)propane; 1,1,1-tris(diphenylphos-
phinomethyl)ethane] (2369 Hz), and both are greater
1
than the J(195Pt, 31P) values of 1492 Hz and 1434 Hz
reported for [Pt(C6H5)2(dpm)] and [Pt(CH3)2(dpm)]
[dpm=bis(diphenylphosphino)methane]
respectively
[30].
Silver nitrate (AgNO3) also displaces the chloro lig-
and and counterion of complexes 1 and 2 with the
formation of 7 and 8 respectively, with the central
phosphorus–platinum coupling constant of 8 now un-
dergoing an increase (240 Hz) compared with the same
coupling constant value for 2; this is in accordance with
the behaviour of NO3− as a better leaving group than
Cl−. This determines for nitrate derivatives 7 and 8 a
higher reactivity than for complexes 1 and 2. In fact,
whereas complex 2 did not react with thiols [9] (such as

48
D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
NMR was recorded for a solution of SnCl2 in dmso-d6;
3.4.2.1. With Au(I). While the chloro (1, 2), bromo (1a,
2a) and iodo (1b) complexes underwent ring-opening
reactions by addition of Au(tdg)Cl [9] (tdg=thiodigly-
col), Au(tdg)Br and AuI respectively, the platinum
complex [Pt(triphos)I]I (2b) does not produce any ring-
opening reaction by titration with AuI (Scheme 2).
However, such a reaction occurred when complex 2b
was titrated with Au(tdg)Cl (Fig. 2) with total disap-
pearance of 2b and formation of the mixed interhalogen
bimetallic complex. The appearance of a signal without
satellites at 34.8 ppm by addition of 2 equiv. of
Au(tdg)Cl was assigned to P bound to linear Au(I) and
the two signals with platinum satellites at 41.3 and
48.9 ppm were assigned to the inequivalent P atoms
bound to Pt(II) in a square-planar centre. The coupling
constants 1J(195Pt, 31P) with values of 3627 and 3631 Hz
(Table 4) were consistent with the presence of P trans to
halogen. This reaction of 2b could be explained by the
presence of relatively labile ligands at Au(I) in the
attacking complex, Au(tdg)Cl, which is important for
inducing ring opening. The presence of chloride as
counterion in complexes [M(triphos)I]Cl, M=Pd (3),
however,
observed.
a new signal at −449 ppm was now
It should be noted that, in Pt(II)–triphos complexes
2
(Table 3), J(PB, PA) is substantially smaller than the
2
usual Jcis(P, P) coupling constants [9]. The order of
2J(PB, PA) seems to depend on the monodentate ligand
bound in the fourth position of the square-planar struc-
ture following the sequence 8\6\2\4. Although for
2
complexes 2a, 2b and 10 this J(PB, PA) coupling con-
stant was not observable, a similar or smaller value to
that of complex 4 is expected. Thus the order of the
coupling constant as a function of the ligand X in
[Pt(triphos)X]+ complexes could be NO3− \CN−\
Cl−\ I−:Br−:PPh3.
The 195Pt NMR spectra for 2, 2a and 2b consist of
doublets of triplets that displace to higher field when
the halogen electronegativity decreases.
3.4.2. Reacti6ity
The reactivity of complexes was followed by 31P
NMR and carried out by titrations with Au(I), KI,
KCN and PPh3.
Fig. 2. Titration of [Pd(triphos)I]I in CDCl3 with Au(tdg)Cl (tdg=thiodiglycol) in MeOH.

D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
49
Table 4
31P{1H} NMR data for titrations of complexes with Au(I)
Phosphorusa
l (ppm)
1J(195Pt, 31P) (Hz)
2J(31P, 31P)(Hz)
1bb
PAc, PB
45.4, 109.5
30.7, 65.2, 75.6
30.5, 65.4, 72.9
6.5
62.9, 9.7
62.9, 9.9
1bd+1 equiv. AuIb
1bd+2 equiv. AuIb
PE, PC, PD
PE, PC, PD
2ae
PAc, PB
PAc, PB
PE, PC, PD
PAc
40.3, 86.7
39.8, 86.9
31.9, 44.3, 49.7
39.6
2464, 2992
3531, 3548
2a+1 equiv. Au(tdg)Bre
62.8
62.1
57.0
2a+2 equiv. Au(tdg)Bre
PE, PC, PD
PAc, PB
PE, PC, PD
PAc, PB
PE, PD
32.1, 44.1, 49.6
40.1, 89.9
34.8, 41.3, 48.9
40.2, 89.9
35.5, 46.8
40.0, 88.9
46.7
3548
2bf
2424, 2895
3631, 3627
2402, 2924
2b+2 equiv. Au(tdg)Clf
2bd+1 equiv. AuIb
2bd+2 equiv. AuIb
PAc, PB
PD
2399, 2926
7b
PAc, PB
47.4, 109.3
31.2, 65.0, 72.2
31.1, 65.1, 72.3
8.5, 8.5
61.6, 54.0
62.0, 58.4
7+1 equiv. Au(tdg)Clg
7+2 equiv. Au(tdg)Clg
PE, PC, PD
PE, PC, PD
8b
PAc, PB
43.4, 73.9
30.5, 41.2, 46.9
30.4, 41.3, 47.0
2596, 3255
3610, 3630
3390, 3627
8.5, 8.5
59.3, 59.5
60.3, 60.4
8+1 equiv. Au(tdg)Clg
8+2 equiv. Au(tdg)Clg
PE, PC, PD
PE, PC, PD
10b
P(PPh3), PAc, PB
Au(PPh3)
PAc, PB
14.2, 45.1, 93.4
31.2
39.7, 83.1
31.2
39.6, 83.1
30.5, 41.3, 46.8
2542, 2381, 2112
2548, 3067
294.2, 21.7, 294.0
10+1 equiv. Au(tdg)Clh
10+2 equiv. Au(tdg)Clh
Au(PPh3)
PAc, PB
2451, 3072
PE, PC, PD
a Phosphorus atoms are labelled in Scheme 2.
b Spectrum recorded in CDCl3.
c Double integration compared with PB.
d 31P{1H} NMR data for titrations of 3 and 4 with AuI were very similar to those of 1b and 2b respectively.
e Spectrum recorded in CDCl3+Et2O.
f Spectrum recorded in CDCl3+MeOH.
g Spectrum recorded in CHCl3+CDCl3+MeOH.
h Spectrum recorded in CH2Cl2+CDCl3+MeOH.
Pt (4), did not modify their reactivity versus AuI and,
consequently, the only ring-opening reaction produced
was for the palladium complex 3 (Table 4).
phosphorus PC of triphos (Scheme 2) instead of the
central phosphorus PD.
As expected, the addition of 1 or 2 equiv. of
Au(tdg)Cl to 7 or 8 led to the heterobimetallic com-
plexes MAu(triphos)(ONO2)2Cl (M=Pd, Pt) (Table 4).
The interaction of [Pt(triphos)(PPh3)](SnCl3)2 (10)
with the first equivalent of Au(tdg)Cl led to the abstrac-
tion of PPh3 with formation (Table 4) of Au(PPh3)Cl
and [Pt(triphos)Cl](SnCl3). The heterobimetallic com-
plex PtAu(triphos)Cl3 was also detected when the sec-
ond equivalent of Au(I) was added.
The titration [9] of [Pt(triphos)Cl]Cl (2) with
Au(tdg)Cl leads to the presence of unreacted complex
besides the heterobimetallic complex PtAu(triphos)Cl3.
However, the titration of [Pt(triphos)Br]Br (2a) with the
first equivalent of Au(tdg)Br (Table 4) led to an in-
significant proportion of unreacted complex 2a com-
pared with that corresponding to the formation of the
heterobimetallic complex PtAu(triphos)Br3. By addition
of the second equivalent of Au(I) the unreacted com-
plex 2a dissappeared.
The cyano complexes [M(triphos)(CN)]Cl, M=Pd
(5), Pt (6), also react with Au(tdg)Cl and induce a ring
opening in both cases. For complex 6 the coupling
constants, 1J(195Pt, 31P), 2454 and 3079 Hz, when
1 equiv. of Au(I) was added were in agreement with P
trans to C and P trans to Cl respectively, indicating that
the cyano group is now bonded trans to the terminal
3.4.2.2. With KX (X=I−, CN−). Complexes 7 and 8
were titrated with KI and KCN (Table 5) and substitu-
tion reactions of NO3− by I− or CN− were observed.
The palladium complex 7 reacted with the first equiva-
lent of KI with apparent formation of [Pd(tri-
phos)I](NO3) from which the nitrate counterion was
displaced by iodide after adding the second equivalent.
With the first equivalent of KI, complex 8 gave rise to

50
D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
Table 5
31P{1H} NMR data for titrations of complexes with KX (X=I, CN) and PPh3
Phosphorusa
l (ppm)
1J(195Pt, 31P) (Hz)
2J(31P, 31P) (Hz)
7b
PAc, PB
PAc, PB
PAc, PB
47.4, 109.3
45.1, 108.3
45.1, 108.3
8.5, 8.5
6.2, 6.2
7+1 equiv. KId
7+2 equiv. KId
8b
PAc, PB
PAc, PB
PAc, PB
PAc, PB
43.4, 73.9
43.1, 73.3
40.1, 89.4
40.0, 89.4
2596, 3255
2563, 3312
2397, 2931
2397, 2930
8.5, 8.5
8+1 equiv. KId
8+2 equiv. KId
7e+1 equiv. KCNd
PAc, PB
PA%c, PB%
PA%c, PB%
47.4, 105.5
19.4, 61.6
19.6, 61.9
7e+2 equiv. KCNd
8e+1 equiv. KCNd
8e+2 equiv. KCNd
PAc, PB
39.2, 89.2
13.2, 48.8
2348, 2256
1389, 2383
PA%c, PB%
d
7+1 equiv. PPh3
PAc, PB
47.1, 108.6
17.3, 52.4, 111.4
47.2, 108.7
P(PPh3), PAc, PB
PAc, PB
309.0, 305.8
304.4, 306.6
d
7+2 equiv. PPh3
P(PPh3), PAc, PB
17.3, 52.4, 111.4
d
8+1 equiv. PPh3
PAc, PB
43.1, 73.4
12.8, 43.1, 94.0
12.8, 43.0, 94.0
2362, 3680
2526, 2362, 2122
2533, 2395, 2122
P(PPh3), PAc, PB
P(PPh3), PAc, PB
291.6, 292.7
291.6, 292.7
d
8+2 equiv. PPh3
a Phosphorus atoms are labelled in Scheme 2 and Fig. 3.
b Spectrum recorded in CDCl3.
c Double integration compared with PB.
d Spectrum recorded in CHCl3+CDCl3+MeOH.
e The titrations of 5 and 6 with KCN were parallel to those of 7 and 8 with 1J(195Pt, 31P) values in 6 of 1395 and 2365 Hz.
led to a mixture of the neutral [Pd(triphos)(CN)2] com-
plex and the unreacted parent cationic complex 7, the
same reaction for [Pt(triphos)(CN)]+ gave the [Pt-
(triphos)(CN)2] complex as the only product. On the
basis of the integration and position of the signals (Fig.
an equimolar almost mixture of unreacted nitrate 8 and
the iodo complex [Pt(triphos)I]I (2b). With the second
equivalent of KI complex 2b was the only species
detected.
The titration of 7 with the first equivalent of KCN
showed the presence of [Pd(triphos)(CN)](NO3) and the
formation of a new complex. With the second equiva-
lent this new cyano derivative was the only species
showing signals shifted to higher field (19.6 and
61.9 ppm) compared with 7. Likewise, by titration of 8
with the first equivalent of KCN the nitrate ligand
substitution by the cyano group occurred. With the
second equivalent the formation of a new complex
isostructural with the palladium compound was de-
tected. The two signals at 13.2 ppm and 48.8 ppm inte-
grating by two and one phosphorus respectively, were
consistent with the formation of a five-coordinate cy-
ano complex, for which the coupling constant
1J(195Pt, 31P) values were 1389 Hz and 2383 Hz respec-
tively. The third equivalent of KCN added produces, in
both complexes 7 and 8, the appearance of free triphos
besides the new five-coordinate complexes. Similarly,
when complexes 5 and 6 were titrated with KCN the
formation of these new M(II) five-coordinate complexes
was also confirmed. The titrations of 5 and 6 with KCN
were parallel to these of 7 and 8. Whereas the addition
of 1 equiv. of KCN to the cation [Pd(triphos)(CN)]+
1
3), as well as the J(195Pt, 31P) values, a trigonal-bypi-
ramidal geometry (undergoing possible pseudo rotation
to give in some extension square-planar pyramidal ge-
ometry) can be proposed.
3.4.2.3. With PPh3. Complexes 7 and 8 were also ti-
trated with PPh3 and the behaviour of NO3− as a better
leaving group compared with Cl− gave rise, as ex-
pected, in both cases to the formation of the complexes
[M(triphos)(PPh3)](NO3)2. However, the palladium
complex 7 needed a higher excess of PPh3 than the
platinum complex 8 for a complete reaction. The addi-
tion of the second equivalent of PPh3 to complex 8
revealed the formation of the [Pt(triphos)(PPh3)](NO3)2
as the only product.
4. Conclusions
In agreement with the higher thermodynamic stabil-
ity and higher kinetic inertness of the platinum com-
pounds compared with analogous palladium complexes,

D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
51
Fig. 3. Titration of [Pt(triphos)(ONO2)](NO3) with KCN in CDCl3+CHCl3+MeOH.
whereas the ionic complexes [Pd(triphos)I]X [X=I (1b),
Cl (3)] react with AuI and Au(tdg)Cl to give novel
bimetallic complexes with linear Au(I) and square-pla-
nar Pd(II) centres, the complexes [Pt(triphos)I]X [X=I
(2b), Cl (4)] do not react with AuI.
tutions by I−, CN− or PPh3 and formation of the new
five-coordinate cyano complexes [M(triphos)(CN)2].
5. Supplementary material
The cyano group trans to the central phosphorus of
triphos in [Pt(triphos)(CN)]Cl converts to trans to a
terminal phosphorus when a ring-opening reaction with
1 equiv. of Au(I) takes place.
The chloro ligand substitution by nitrato generates the
complexes 7 and 8 with X-ray crystal structures showing
a distorted square-planar geometry for the metal which
is bound to the three phosphorus atoms of the phosphine
ligand and one oxygen of the NO3− retaining its trigo-
nal-planar geometry. These nitrate derivatives undergo
ring-opening reactions with Au(I), nitrato ligand substi-
Tables of atomic coordinates, bond distances and
bond angles and anisotropic thermal parameters for
complexes 7 (CCDC No. 149646) and 8 (CCDC No.
149647) are supplied as an Annex. A complete set of
X-ray crystallographic structural studies for complexes 7
(CCDC No. 149646) and 8 (CCDC No. 149647) is
available at the Cambridge Crystallographic Data Cen-
tre, 12 Union Road, Cambridge CB2 1EZ, UK (fax:
+44-1223-336-033; e-mail: deposit@ccdc.cam.ac.uk) on
request, quoting the deposition number.

52
D. Ferna´ndez et al. / Inorganica Chimica Acta 312 (2001) 40–52
[11] CAD4-Express Software, Version 5.1, Enraf–Nonius, Delft, The
Acknowledgements
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The authors thank the Xunta de Galicia in Spain
(Project XUGA 20906A98 and Predoctoral Grant for
M.I. Garc´ıa Seijo) and the Hungarian National Science
Foundation for financial support (OTKAT23525) and
the Ministry of Education (Grant FKFP0242).
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Ellipsoids, University of Heidelberg, Germany, 1997.
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