Reaction of [MCl2(CH3CN)2] (M = Pd(II), Pt(II)) compounds with N1-alkylpyridylpyrazole-derived ligands

Article abstract of DOI:10.1016/j.ica.2005.07.047

Palladium(II) and platinum(II) complexes with N-alkylpyridylpyrazole- derived ligands, 2-(1-ethyl-5-phenyl-1H-pyrazol-3-yl)pyridine (L¹) and 2-(1-octyl-5-phenyl-1H-pyrazol-3-yl)pyridine (L²), cis-[MCl ₂(L)] (M = Pd(II), Pt(II)), have been synthesised. Treatment of [PdCl₂(L)] (L = L¹, L²) with excess of ligand (L¹, L²), pyridine (py) or triphenylphosphine (PPh ₃) in the presence of AgBF₄ and NaBPh₄ produced the following complexes: [Pd(L)₂](BPh₄)₂, [Pd(L)(py)₂](BPh₄)₂ and [Pd(L)(PPh ₃)₂](BPh₄)₂. All complexes have been characterised by elemental analyses, conductivity, IR and NMR spectroscopies. The crystal structures of cis-[PdCl₂(L²)] (2) and cis-[PtCl₂(L¹)] (3) were determined by a single crystal X-ray diffraction method. In both complexes, the metal atom is coordinated by one pyrazole nitrogen, one pyridine nitrogen and two chlorine atoms in a distorted square-planar geometry. In complex 3, π-π stacking between pairs of molecules is observed.

Full text of DOI:10.1016/j.ica.2005.07.047

Inorganica Chimica Acta 359 (2006) 25–34
www.elsevier.com/locate/ica
Reaction of [MCl2(CH3CN)2] (M = Pd(II), Pt(II)) compounds with
N1-alkylpyridylpyrazole-derived ligands
a
a,
b
b
a
*
`
Vanessa Montoya , Josefina Pons , Xavier Solans , Merce Font-Bardia , Josep Ros
a
` ` `
Departament de Quı´mica, Unitat de Quı´mica Inorganica, Facultat de Ciencies, Universitat Autonoma de Barcelona,
08193 Bellaterra-Cerdanyola, Barcelona, Spain
´
b
` `
Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Martı i Franques s/n, 08028-Barcelona, Spain
Received 13 April 2005; accepted 22 July 2005
Available online 22 November 2005
Abstract
Palladium(II) and platinum(II) complexes with N-alkylpyridylpyrazole-derived ligands, 2-(1-ethyl-5-phenyl-1H-pyrazol-3-yl)pyridine
(L1) and 2-(1-octyl-5-phenyl-1H-pyrazol-3-yl)pyridine (L2), cis-[MCl2(L)] (M = Pd(II), Pt(II)), have been synthesised. Treatment of
[PdCl2(L)] (L = L1, L2) with excess of ligand (L1, L2), pyridine (py) or triphenylphosphine (PPh3) in the presence of AgBF4 and NaBPh4
produced the following complexes: [Pd(L)2](BPh4)2, [Pd(L)(py)2](BPh4)2 and [Pd(L)(PPh3)2](BPh4)2. All complexes have been character-
ised by elemental analyses, conductivity, IR and NMR spectroscopies. The crystal structures of cis-[PdCl2(L2)] (2) and cis-[PtCl2(L1)] (3)
were determined by a single crystal X-ray diffraction method. In both complexes, the metal atom is coordinated by one pyrazole nitrogen,
one pyridine nitrogen and two chlorine atoms in a distorted square-planar geometry. In complex 3, p–p stacking between pairs of mol-
ecules is observed.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: N1-Alkylpyridylpyrazole ligands; Palladium complexes; Platinum complexes; Crystal structures
1. Introduction
ligands. In a recent paper, we presented the synthesis and
characterisation of the ligands, 2-(1-ethyl-5-phenyl-1H-pyra-
The coordination chemistry of the pyrazole-derived
ligands has been extensively studied in recent years [1–5].
Over the last few years, we have invested much time and
energy in developing the coordination chemistry of 3,5-
substituted pyrazole-derived ligands. This chemistry is rich
in structural types, reactivity characteristics and ligand
coordination modes [6–18]. These ligands, can potentially
combine chelating properties with bridging properties.
The study of the transition metal complexes of these
ligands is important in catalysis, bioinorganic and materi-
als chemistry, moreover, it leads to the study of magnetic
coupling interactions.
zol-3-yl)-pyridine (L1), 2-(2-ethyl-5-phenyl-1H-pyrazol-3-yl)-
0
pyridine ðL1 Þ, 2-(1-octyl-5-phenyl-1H-pyrazol-3-yl)-pyridine
0
(L2), 2-(2-octyl-5-phenyl-1H-pyrazol-3-yl)-pyridine ðL2 Þ,
1-ethyl-5-methyl-3-phenyl-1H-pyrazole (L3), 2-ethyl-5-methyl-
0
3-phenyl-1H-pyrazole ðL3 Þ, 5-methyl-1-octyl-3-phenyl-1H-
0
pyrazole (L4), 5-methyl-2-octyl-3-phenyl-1H-pyrazole ðL4 Þ,
2-(1-ethyl-5-trifluoromethyl-1H-pyrazol-3-yl)-pyridine (L5),
2-(1-octyl-5-trifluoromethyl-1H-pyrazol-3-yl)-pyridine (L6),
2-(1-ethyl-5-methyl-1H-pyrazol-3-yl)-pyridine (L7) and 2-
(5-methyl-1-octyl-1H-pyrazol-3-yl)-pyridine (L8) [19]. With
the ligands (L3) and (L4), we obtained and fully character-
ised the dichlorocomplexes trans-[MCl2(L)2] (M = Pd(II):
L = L3, L4; Pt(II): L = L3, L4) [20]. In a second paper,
the synthesis and characterisation of the ligands, 1-ethyl-
3,5-bis(2-pyridyl)pyrazole (L9) and 1-octyl-3,5-bis(2-pyr-
idyl)pyrazole (L10), and their reactivity with Pd(II) and
Pt(II) was presented [21].
Recently, our investigations have been directed towards
the preparation of 1,3,5-substituted pyrazole-derived
*
Corresponding author. Tel.: +34 93 581 28 95; fax: +34 93 581 31 01.
E-mail address: Josefina.Pons@uab.es (J. Pons).
0020-1693/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.07.047

26
V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
As an extension of the above results, the present paper
a solution of [PdCl2(CH3CN)2] (0.38 mmol; 0.10 g) in dry
acetonitrile (20 ml). The solution resulting was stirred at
room temperature for 10 h. The solution was concentrated
until a crystalline precipitate appeared. The complex pre-
cipitates as orange needles and recrystallised in acetone.
The solid was filtered off, washed with diethyl ether
(5 ml) and dried in vacuum.
describes the reaction of the ligands L1 and L2 with [MCl2-
(CH3CN)2] (M = Pd(II), Pt(II)) yielding the compounds
[MCl2(L)] (M = Pd(II): L = L1 (1), L = L2 (2); Pt(II):
L = L1 (3), L = L2 (4)). Treatment of the complexes [PdCl2-
(L)] (L = L1 (1), L2 (2)) with excess of ligand (L), pyridine
(py) or triphenylphosphine (PPh3) in the presence of AgBF4
and NaBPh4, yielding the compounds [Pd(L)2](BPh4)2
(L = L1 (5), L2 (6)), [Pd(L)(py)2](BPh4)2 (L = L1 (7), L2
(8)) and [Pd(L)(PPh3)2](BPh4)2 (L = L1 (9), L2 (10)).
1: (Yield: 80%) Anal. Calc. for C16H15N3Cl2Pd: C,
45.03; H, 3.52; N, 9.8ꢀ5.1 Found: C, 44.85; H, 3.14; N,
9.59%. Conductivity (X cm2 molꢀ1, 1.0 · 10ꢀ3 M in ace-
tone): 2.7. IR: (KBr, cmꢀ1): 3099 m(C–H)ar, 2993 m(C–H)al,
1613 (m(C@C), m(C@N))ar, 1465, 1445 (d(C@C), d(C@
N))ar, 785, 765 d(C–H)oop; (polyethylene, cmꢀ1): 435
2. Experimental
1
2.1. General details
m(Pd–N), 352, 330 m(Pd–Cl). H NMR: (CDCl3 solution,
3
250 MHz) d: 9.35 [1H, d, J = 6.0 Hz, H1], 8.02 [1H, t,
3
All reactions were carried out with the use of vacuum
line and Schlenk techniques. All reagents were commercial
grade materials and were used without further purification.
All solvents were dried and distilled by standard methods.
The elemental analyses (C, N, H) were carried out by
the staff of the Chemical Analyses Service of the Universi-
3J = 8.0 Hz, H3], 7.72 [1H, d, J = 8.0 Hz, H4], 7.59–7.55
[3H, m, H2, H6, H10], 7.46–7.43 [3H, m, H7, H8, H9], 6.77
3
[1H, s, H5], 4.86 [2H, q, J = 7.0 Hz, pz–CH2–CH3], 1.41
[3H, t, 3J = 7.0 Hz, pz–CH2–CH3] ppm. 13C{1H} NMR
(CDCl3 solution, 63 MHz) d: 152.1 (C12), 151.6 (C11),
151.1 (C1), 148.7 (C13), 140.3 (C3), 130.9 (C14), 129.7 (C7,
C9), 129.5 (C6, C10), 128.3 (C8), 124.8 (C2), 121.4 (C4),
105.1 (C5), 45.9 (CH2–CH3), 17.1 (CH2–CH3) ppm.
`
tat Autonoma de Barcelona on a Carlo Erba CHNS
EA-1108 instrument. Conductivity measurements were per-
formed at room temperature (r.t.) in 10ꢀ3 M acetone solu-
tions employing a Crison, micro CM 2200 conductimeter.
Infrared spectra were run on a Perkin–Elmer FT spectro-
photometer series 2000 cmꢀ1 as KBr pellets or polyethylene
films in the range 4000–100 cmꢀ1 under a nitrogen atmo-
sphere. The 1H NMR, 13C{1H} NMR, 31P{1H} NMR
and HMQC spectra were run on a NMR-FT Bruker
250 MHz spectrometer in CDCl3 or CD2Cl2 solutions at
room temperature. 1H NMR and 13C{1H} NMR chemical
shifts (d) were determined relative to internal TMS and are
given in ppm. 31P{1H} NMR chemical shifts (d) are relative
to external 85% H3PO4 are given in ppm. Electrospray
mass spectra were obtained on an Esquire 3000 ion trap
mass spectrometer from Bruker Daltonics (ESI-IT).
2: (Yield: 71%) Anal. Calc. for C22H27N3Cl2Pd: C,
51.72; H, 5.29; N, 8.23. Found: C, 51.36; H, 4.90; N,
8.95%. Conductivity (Xꢀ1 cm2 molꢀ1, 1.1 · 10ꢀ3 M in ace-
tone): 1.1. IR: (KBr, cmꢀ1): 3100 m(C–H)ar, 2923 m(C–H)al,
1612 (m(C@C), m(C@N))ar, 1458 (d(C@C), d(C@N))ar, 761
d(C–H)oop; (polyethylene, cmꢀ1): 425 m(Pd–N), 357, 340
1
m(Pd–Cl). H NMR: (CDCl3 solution, 250 MHz) d: 9.36
[1H, d, 3J = 5.0 Hz, H1], 8.01 [1H, t, 3J = 8.0 Hz, H3],
3
7.70 [1H, d, J = 8.0 Hz, H4], 7.58–7.56 [3H, m, H2, H6,
H10], 7.45–7.41 [3H, m, H7, H8, H9], 6.75 [1H, s, H5],
3
4.81 [2H, t, J = 7.0 Hz, pz–CH2–CH2–(CH2)5–CH3], 1.83
[2H, m, pz–CH2–CH2–(CH2)5–CH3], 1.21–1.13 [10H, m,
pz–CH2–CH2–(CH2)5–CH3], 0.84 [3H, 3J = 7.0 Hz, pz–
CH2–CH2–(CH2)5–CH3] ppm. 13C{1H} NMR (CDCl3
solution, 63 MHz) d: 152.1 (C12), 151.6 (C11), 151.2 (C1),
149.3 (C13), 140.3 (C3), 130.8 (C14), 129.7 (C7, C9), 129.5
(C6, C10), 128.5 (C8), 124.7 (C2), 121.3 (C4), 104.8 (C5),
50.5 (CH2–(CH2)6–CH3), 32.1–23.0 (CH2–(CH2)6–CH3),
14.5 (CH2–(CH2)6–CH3) ppm.
Synthesis of 2-(1-ethyl-5-phenyl-1H-pyrazol-3-yl)pyri-
dine (L1) and 2-(1-octyl-5-phenyl-1H-pyrazol-3-yl)pyridine
(L2) have previously been reported in the literature [19]
(Fig. 1). Samples of [MCl2(CH3CN)2] (M = Pd(II) [22],
Pt(II) [23]) were prepared as described in the literature.
2.2. Synthesis of the complexes
2.2.2. Complexes [PtCl2(L)] (L = L1 (3); L2 (4))
The appropriate ligand (0.40 mmol: L1, 0.10 g; L2,
0.13 g) dissolved in 15 ml of dry acetonitrile was added to
solution of [PtCl2(CH3CN)2] (0.40 mmol; 0.14 g) dissolved
in 20 ml of the same solvent. The mixture was heated to
reflux for 48 h. The solvent was then evaporated under
reduced pressure and a crystalline precipitate appeared.
The yellow solid was filtered off, washed with diethyl ether
and dried in vacuum.
3: (Yield: 53%) Anal. Calc. for C16H15N3Cl2Pt: C, 37.27;
H, 2.91; N, 8.15. Found: C, 37.18; H, 2.53; N, 8.13%. Con-
ductivity (Xꢀ1 cm2 molꢀ1, 1.0 · 10ꢀ3 M in acetone): 1.6.
IR: (KBr, cmꢀ1): 3102 m(C–H)ar, 2993 m(C–H)al, 1618
(m(C@C), m(C@N))ar, 1465, 1445 (d(C@C), d(C@N))ar,
2.2.1. Complexes [PdCl2(L)] (L = L1 (1); L2 (2))
The appropriate ligand (0.38 mmol: L1, 0.095 g; L2,
0.13 g) dissolved in dry acetonitrile (40 ml) was added to
3
7
6
4
5
2
14
13
8
12
R = ethyl
R = octyl
11
N
1
9
N
N
10
R
Fig. 1. N1-Alkylpyridylpyrazole-derived ligands and numbering scheme.

V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
27
783, 765 d(C–H)oop; (polyethylene, cmꢀ1): 441 m(Pt–N),
CH3), 15.9 (CH2–CH3) ppm. MS (%): 604 (44%)
[Pd(L1)2]2+, 355 (6%) [Pd(L1)2-L1]2+, 250 (100%) [L1 + H]+.
[6](BPh4)2: (Yield: 87%) Anal. Calc. for C92H94B2N6Pd:
C, 78.27; H, 6.67; N, 5.96. Found: C, 78.43; H, 6.60; N,
6.64%. Conductivity (Xꢀ1 cm2 molꢀ1, 9.9 · 10ꢀ4 M in ace-
tone): 176.5. IR: (KBr, cmꢀ1) 3055 m(C–H)ar, 2925 m(C–
H)al, 1606, 1579 (m(C@C), m(C@N))ar, 1480, 1460, 1426
(d(C@C), d(C@N))ar, 780, 732, 703 d(C–H)oop, 612 m(B–
1
349, 331 m(Pt–Cl). H NMR: (CDCl3 solution, 250 MHz)
3
3
d: 9.74 [1H, d, J = 6.0 Hz, H1], 8.06 [1H, t, J = 8.0 Hz,
3
H3], 7.73 [1H, d, J = 8.0 Hz, H4], 7.60–7.57 [3H, m, H2,
H6, H10], 7.48–7.44 [3H, m, H7, H8, H9], 6.80 [1H, s, H5],
4.97 [2H, q, 3J = 7.0 Hz, pz–CH2–CH3], 1.44 [3H, t,
3J = 7.0 Hz, pz–CH2–CH3] ppm. 13C{1H} NMR (CDCl3
solution, 63 MHz) d: 153.1 (C12), 152.7 (C11), 150.0 (C1),
148.7 (C13), 139.6 (C3), 131.0 (C14), 129.7 (C7, C9), 129.5
(C6, C10), 128.5 (C8), 125.1 (C2), 121.4 (C4), 105.4 (C5),
46.1 (CH2–CH3), 16.9 (CH2–CH3) ppm.
1
C); (polyethylene, cmꢀ1): 469 m(Pd–N). H NMR (CDCl3
3
solution, 250 MHz) d: 8.66 [2H, d, J = 4.1 Hz H1], 8.01–
6.73 [56H, m, HPh, Hpy], 7.38 [2H, s, H5], 4.20 [4H, t,
3J = 7.5 Hz, CH2–CH2–(CH2)5–CH3], 1.90–1.85 [4H, m,
CH2–CH2–(CH2)5–CH3], 1.36–1.22 [20H, m, CH2–CH2–
4: (Yield: 40%) Anal. Calc. for C22H27N3Cl2Pt: C, 44.07;
H, 4.51; N, 7.01. Found: C, 43.85; H, 4.39; N, 7.90%. Con-
ductivity (Xꢀ1 cm2 molꢀ1, 9.8 · 10ꢀ4 M in acetone): 1.3.
IR: (KBr, cmꢀ1): 3085 m(C–H)ar, 2923 m(C–H)al, 1621
(m(C@C), m(C@N))ar, 1459 (d(C@C), d(C@N))ar, 763 d(C–
H)oop; (polyethylene, cmꢀ1): 433 m(Pt–N), 351, 339 m(Pt–
3
(CH2)5–CH3]. 0.88 [6H, t, J = 7.3 Hz, CH2–(CH2)6–CH3]
ppm. 13C{1H} NMR (CD2Cl2 solution, 63 MHz) d: 149.7
(C1), 136.8–120.0 (CPh, Cpy), 104.9 (C5), 50.3 (CH2–
(CH2)6–CH3), 32.1–22.9 (CH2–(CH2)6–CH3), 14.2 (CH2–
(CH2)6–CH3) ppm. MS (%): 772 (9%) [Pd(L2)2]2+, 440
(5%) [Pd(L2)2-L2]2+, 334 (15%) [L2 + H]+.
1
Cl). H NMR: (CDCl3 solution, 250 MHz) d: 9.77 [1H,
d, 3J = 6.0 Hz, H1], 8.05 [1H, t, 3J = 8.0 Hz, H3], 7.70
3
[1H, d, J = 7.0 Hz, H4], 7.59–7.56 [3H, m, H2, H6, H10],
7.46–7.43 [3H, m, H7, H8, H9], 6.78 [1H, s, H5], 4.92 [2H,
2.2.4. Complexes [Pd(L)(py)2](BPh4)2 (L = L1
[7](BPh4)2; L2 [8](BPh4)2)
3
t, J = 7.0 Hz, pz–CH2–CH2–(CH2)5–CH3], 1.89 [2H, m,
pz–CH2–CH2–(CH2)5–CH3], 1.21–1.13 [10H, m, pz–CH2–
CH2–(CH2)5–CH3], 0.84 [3H, J = 7.0 Hz, pz–CH2–CH2–
A solution of 1 (0.16 mmol; 0.068 g) or 2 (0.16 mmol;
0.082 g) was dissolved in a mixture of CH2Cl2/MeOH
(3:1) (20 ml). About (0.32 mmol; 0.025 g) of pyridine was
then added, followed immediately by a solution of AgBF4
(0.32 mmol; 0.062 g) dissolved in methanol (2 ml). The
reaction was carried out in the dark to prevent reduction
of Ag(I) to Ag(0). After 5 min, stirring was stopped and
AgCl was filtered off through Celite pad. Solution had
turned from initial orange to bright yellow. The solution
was stirred for 1 h and concentrated on a vacuum line to
one-fifth of the initial volume. NaBPh4 (0.32 mmol;
0.11 g) was added and then precipitate a yellow solid. This
solid was filtered off, washed in diethyl ether and dried in
vacuum.
3
(CH2)5–CH3] ppm. 13C{1H} NMR (CDCl3 solution,
63 MHz) d: 153.1 (C12), 152.6 (C11), 149.8 (C1), 149.1
(C13), 139.7 (C3), 130.8 (C14), 129.7 (C7, C9), 129.6 (C6,
C10), 128.6 (C8), 125.0 (C2), 121.7 (C4), 105.3 (C5), 50.6
(CH2–(CH2)6–CH3), 32.1–23.0 (CH2–(CH2)6–CH3), 14.5
(CH2–(CH2)6–CH3) ppm.
2.2.3. Complexes [Pd(L)2](BPh4)2 (L = L1 [5](BPh4)2;
L2 [6](BPh4)2)
The appropriate ligand (0.18 mmol: L1, 0.045 g; L2,
0.060 g) dissolved in CH2Cl2/MeOH (3:1) (20 ml) was
added to a solution of 1 (0.18 mmol; 0.077 g) or 2
(0.18 mmol; 0.092 g) respectively, dissolved in CH2Cl2/
MeOH (3:1) (20 ml). AgBF4 (0.36 mmol; 0.070 g) was dis-
solved in MeOH (5 ml). This solution was stirred at r.t.
and light protected for 5 min. The yellow solution was then
filtered through a pad of Celite. The solution was stirred
for 1 h and concentrated on a vacuum line to one-fifth of
the initial volume. NaBPh4 (0.36 mmol; 0.12 g) was added
and then precipitate an orange solid. This solid was filtered
off, washed in diethyl ether and dried in vacuum.
[7](BPh4)2: (Yield: 86%) Anal. Calc. for C74H65B2N5Pd:
C, 77.15; H, 5.65; N, 6.08. Found: C, 77.56; H, 5.24; N,
6.97%. Conductivity (Xꢀ1 cm2 molꢀ1, 9.6 · 10ꢀ4 M in ace-
tone):176.5. IR: (KBr, cmꢀ1) 3055 m(C–H)ar, 2925 m(C–
H)al, 1611 (m(C@C), m(C@N))ar,py, 1605, 1579 (m(C@C),
m(C@N))ar, 1479, 1425 (d(C@C), d(C@N))ar, 1451
(d(C@C), d(C@N))ar,py, 765, 733, 705 d(C–H)oop, 612
m(B–C); (polyethylene, cmꢀ1): 469 m(Pd–N). 1H NMR
3
(CDCl3 solution, 250 MHz) d: 8.92 [1H, d, J = 4.7 Hz,
[5](BPh4)2: (Yield: 84%) Anal. Calc. for C80H70B2N6Pd:
C, 77.29; H, 5.63; N, 6.76. Found: C, 77.74; H, 5.90; N,
6.62%. Conductivity (Xꢀ1 cm2 molꢀ1, 9.6 · 10ꢀ4 M in ace-
tone): 163.1. IR: (KBr, cmꢀ1) 3055 m(C–H)ar, 2925 m(C–
H)al, 1605, 1579 (m(C@C), m(C@N))ar, 1480, 1464, 1425
(d(C@C), d (C@N))ar, 765, 732, 703 d(C–H)oop, 612 m(B–
H1], 8.78 [2H, d, 3J = 4.8 Hz, Hpy], 8.69 [2H, d,
3J = 5.0 Hz, Hpy], 8.10–6.82 [54H, m, HPh, Hpy], 7.26
[1H, s, H5], 4.81 [2H, q, 3J = 7.2 Hz, CH2–CH3], 1.44
[3H, t, 3J = 7.2 Hz, CH2–CH3] ppm. 13C{1H} NMR
(CD2Cl2 solution, 63 MHz) d: 149.7 (C1), 136.8–120.0
(CPh, Cpy), 104.9 (C5), 45.8 (CH2–CH3), 14.7 (CH2–CH3)
ppm. MS (%) = 513 (11%) [Pd(L1)(py)2]2+, 250 (100%)
[L1 + H+], 92 (54%) [py + H+].
1
C); (polyethylene, cmꢀ1): 468 m(Pd–N). H NMR: (CDCl3
3
solution, 250 MHz) d: 8.65 [2H, d, J = 4.5 Hz H1], 8.00–
6.85 [56H, m, HPh, Hpy], 7.39 [2H, s, H5], 4.26 [4H, q,
3J = 7.3 Hz, CH2–CH3] 1.48 [6H, t, 3J = 7.3 Hz, CH2–
CH3] ppm. 13C{1H} NMR (CD2Cl2 solution, 63 MHz) d:
146.7 (C1), 136.1–122.2 (CPh, Cpy), 104.9 (C5), 45.7 (CH2–
[8](BPh4)2: (Yield: 85%) Anal. Calc. for C80H77B2N5Pd:
C, 77.73; H, 6.23; N, 5.67. Found: C, 77.97; H, 6.43; N,
6.02%. Conductivity (Xꢀ1 cm2 molꢀ1, 9.7 · 10ꢀ4 M in
acetone): 175.8. IR: (KBr, cmꢀ1) 3055 m(C–H)ar, 2925

28
V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
m(C–H)al, 1611 (m(C@C), m(C@N))ar,py
,
1605, 1579
3J = 5.0 Hz, H1], 7.71–6.87 [78H, m, HPh, Hpy], 7.10 [1H,
s, H5], 4.19 [2H, t, J = 6.5 Hz, CH2–(CH2)6–CH3], 1.95–
3
(m(C@C), m(C@N))ar, 1480, 1464, 1425 (d(C@C),
d(C@N))ar, 1451 (d(C@C), d(C@N))ar,py, 762, 732, 705
d(C–H)oop, 612 m(B–C); (polyethylene, cmꢀ1): 467 m(Pd–
1.84 [2H, m, CH2–CH2–(CH2)5–CH3], 1.62–1.51 [10H, m,
CH2–CH2–(CH2)5–CH3], 0.87 [3H, t, 3J = 6.1 Hz, CH2–
(CH2)6–CH3] ppm. 13C{1H} NMR (CD2Cl2 solution,
63 MHz) d: 149.2 (C1), 135.5–127.5 (CPh, Cpy), 105.4
(C5), 50.3 (CH2–(CH2)6–CH3), 32.1–21.5 (CH2–(CH2)6–
CH3), 13.4 (CH2–(CH2)6–CH3) ppm. 31P{1H} NMR
(CD2Cl2 solution, 81 MHz) d: 33.5 (br, PPh3), 33.6 (br,
1
N). H NMR (CDCl3 solution, 250 MHz) d: 8.86 [1H, d,
3
3J = 5.3 Hz, H1], 8.79 [2H, d, J = 4.7 Hz, Hpy], 8.63 [2H,
3
d, J = 5.1 Hz, Hpy], 7.84–6.89 [54H, m, HPh, Hpy], 7.24
3
[1H, s, H5], 3.77 [2H, t, J = 6.8 Hz, CH2–(CH2)6–CH3],
1.90–1.85 [2H, m, CH2–CH2–(CH2)5–CH3], 1.35–1.24
[10H, m, CH2–CH2–(CH2)5–CH3], 0.81 [3H, t, 3J =
7.2 Hz, CH2–(CH2)6–CH3] ppm. 13C{1H} NMR (CD2Cl2
solution, 63 MHz) d: 149.6 (C1), 136.9–121.1 (CPh, Cpy),
103.4 (C5), 50.5 (CH2–(CH2)6–CH3), 32.1–23.0 (CH2–
(CH2)6–CH3), 14.4 (CH2–(CH2)6–CH3) ppm. MS
(%) = 595 (27%) [Pd(L2)(py)2]2+, 334 (30%) [L2 + H+], 92
(100%) [py + H+].
PPh3). MS (%) = 963 (<1%) [Pd(L2)(PPh3)2]2+
, 701
(100%) [Pd(L2)(PPh3)2-PPh3], 334 (6%) [L2 + H]+, 263
(4%) [PPh3 + H+].
2.3. X-ray crystal structure analyses of complex
[PdCl2(L2)] (2)
Suitable crystals for X-ray diffraction of compound cis-
[PdCl2(L2)] (2) were obtained thorough crystallisation from
acetone. One crystal mounted on an Enraf-Nonius CAD4
four-circle diffractometer with a image plate detector.
Unit-cell parameters were determined from automatic cen-
tering of 25 reflections (12 < h < 21) and refined by least-
squares method. Intensities were collected with graphite
monochromatised Mo Ka radiation, using x/2h scan-tech-
nique. 6399 reflections were measured in the range
2.38 6 h 6 29.97. 6398 of which were non-equivalent by
symmetry (Rint (on I) = 0.012). 3762 reflections were
assumed as observed applying the condition I > 2r(I).
Three reflections were measured every two hours as orien-
tation and intensity control, significant intensity decay was
not observed. Lorentz–polarisation but no absorption cor-
rections were made.
2.2.5. Complexes [Pd(L)(PPh3)2](BPh4)2 (L = L1
[9](BPh4)2; L2 [10](BPh4)2)
A solution of 1 (0.14 mmol; 0.060 g) or 2 (0.14 mmol;
0.071 g) was dissolved in a mixture of CH2Cl2 (10 ml),
MeOH (10 ml) and CH3CN (2 ml). Then, a solution of
AgBF4 (0.28 mmol; 0.054 g) in methanol (2 ml) was added
dropwise with vigorous stirring at r.t. and light protected
for 5 min. This solution is orange. To this solution
(0.28 mmol; 0.073 g) of PPh3 was added. The solution
turned red. After 1 h the red solution turned yellow. This
solution was stirred at r.t. for 5 h and concentrated on a
vacuum line to one-fifth of the initial volume. NaBPh4
(0.28 mmol; 0.096 g) was added and then precipitate a yel-
low solid. This solid was filtered off, washed in diethyl ether
and dried in vacuum.
[9](BPh4)2: (Yield: 63%) Anal. Calc. for C100H85B2N3P2Pd:
C, 79.10; H, 5.60; N, 2.77. Found: C, 79.03; H, 5.34; N,
2.97%. Conductivity (Xꢀ1 cm2 molꢀ1, 1.04 · 10ꢀ3 M in
acetone):169.0. IR: (KBr, cmꢀ1) 3059 m(C–H)ar, 2927
m(C–H)al, 1605, 1570 (m(C@C), m(C@N))ar, 1482, 1436
(d(C@C), d(C@N))ar, 744, 695 d(C–H)oop, 612 m(B–C),
(polyethylene, cmꢀ1): 450 m(Pd–N), 341 m(Pd–P). 1H
NMR (CDCl3 solution, 250 MHz) d: 8.57 [1H, d,
3J = 4.8 Hz H1], 7.65–7.19 [78H, m, HPh, Hpy] 6.97 [1H,
The structure was solved by Direct methods, using
SHELXS computer program [24] and refined by full-matrix
least-squares method with SHELXL97 computer program
[25], using 6398 reflections. The function minimised was
P
2
2 2
wjjF oj ꢀ jF cj j , where w = [r2(I) + (0.0348P)2]ꢀ1 and
2
2
P ¼ ðjF oj þ 2jF cj Þ=3. 22H atoms were located from a dif-
ference synthesis and refined with overall isotropic temper-
ature factor and 5H atoms were computed and refined,
using a riding model, with an isotropic temperature factor
equal to 1.2 times the equivalent temperature factor of the
atom, which are linked. The final R(F) factor and R(F2)
values as well as the number of parameters and other
details concerning the refinement of the crystal structure
are gathered in Table 1.
3
s, H5], 4.17 [2H, q, J = 7.3 Hz, CH2–CH3], 1.32 [3H, t,
3J = 7.3 Hz, CH2–CH3]. 13C{1H} NMR (CD2Cl2 solution,
63 MHz). d: 150.3 (C1), 134.6–122.8 (CPh, Cpy), 103.3 (C5),
50.4 (CH2–CH3), 14.6 (CH2–CH3) ppm. 31P{1H} NMR
(CD2Cl2 solution, 81 MHz) d: 35.1 (br, PPh3), 34.8 (br,
PPh3). MS (%) = 879 (<1%) [Pd(L1)(PPh3)2]2+
, 617
(100%) [Pd(L1)(PPh3)2-PPh3], 250 (13%) [L1 + H]+, 263
(68%) [PPh3 + H+].
2.4. X-ray crystal structure analyses of complex
[PtCl2(L1)] (3)
[10](BPh4)2: (Yield: 51%) Anal. Calc. for C106H97B2N3-
P2Pd: C, 79.44; H, 6.06; N, 2.62. Found: C, 79.74; H,
5.90; N, 2.62%. Conductivity (Xꢀ1 cm2 molꢀ1, 1.00 ·
10ꢀ3 M in acetone): 167.2. IR: (KBr, cmꢀ1) 3054 m(C–
H)ar, 2925 m(C–H)al, 1605, 1579 (m(C@C), m(C@N))ar,
1480, 1436 (d(C@C), d(C@N))ar, 732, 704 d(C–H)oop, 612
m(B–C), (polyethylene, cmꢀ1): 471 m(Pd–N), 344 m(Pd–P).
1H NMR (CDCl3 solution, 250 MHz) d: 8.68 [1H, d,
Suitable crystals for X-ray diffraction of compound cis-
[PtCl2(L1)] (3) were obtained thorough crystallisation from
acetone. One crystal mounted on an Enraf-Nonius CAD4
four-circle diffractometer. Unit-cell parameters were deter-
mined from automatic centering of 25 reflections (12 < h <
21) and refined by least-squares method. Intensities
were collected with graphite monochromatised Mo Ka

V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
29
Table 1
The structure was solved by Direct methods, using
SHELXS computer program [24] and refined by full-matrix
least-squares method with SHELXL97 computer program
Crystallographic data for cis-[PdCl2(L2)] (2)
Formula
M
Temperature (K)
Crystal system
Space group
Unit cell dimensions
C22H27Cl2N3Pd
510.77
293(2)
triclinic
[25], using 4833 reflections. The function minimised was
P
2
2 2
wjjF oj ꢀ jF cj j , where w = [r2(I) + (0.0485P)2]ꢀ1 and
2
2
P ¼ ðjF oj þ 2jF cj Þ=3. All H atoms were computed and
refined using a riding model, with an isotropic temperature
factor equal to 1.2 times the equivalent temperature factor
of the atom, which are linked. The final R(F) factor and
R(F2) values as well as the number of parameters and other
details concerning the refinement of the crystal structure
are gathered in Table 2.
ꢀ
P1 No. 2
˚
a (A)
8.815(4)
9.241(7)
14.688(2)
86.99(2)
87.18(2)
68.10(5)
1108.0(10)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
U (A )
Z
2
3. Results and discussion
Dcalc (g cmꢀ3
)
1.531
1.091
520
l (mmꢀ1
F(000)
)
3.1. Synthesis and spectroscopic properties of complexes 1–4
Crystal size
h Range (ꢁ)
Index range
Reflections collected/unique
Data/restraints/parameters
Goodness-of-fit
Final R1, xR2
R1 (all data), xR2
Residual electron density (e A
0.1 · 0.1 · 0.2
2.38–29.97
ꢀ12 < h < 12, ꢀ12 < k < 12, 0 < l < 20
6399/6398 [Rint = 0.0125]
6398/0/341
The complexes cis-[MCl2(L)] (M = Pd(II): L = L1 (1),
L = L2 (2); M = Pt(II): L = L1 (3), L = L2 (4)) were
obtained by reaction of [MCl2(CH3CN)2] (M = Pd(II),
Pt(II)) with the corresponding pyrazole ligand (L1, L2), in
an acetonitrile solution and in the 1M:1L ratio. These com-
plexes are soluble in CHCl3, CH2Cl2, acetone but insoluble
in acetonitrile, hexane, diethyl ether, methanol and etha-
nol. The ability of L1 and L2 to coordinate Pd(II) and
Pt(II) is comparable to that of the N-alkylpyrazoles [21].
The elemental analyses are consistent with the formula
[MCl2(L)] for the four compounds. Conductivity measure-
1.015
0.0543, 0.0834
0.1468, 0.1008
0.566 and ꢀ0.691
ꢀ3
˚
)
radiation, using x/2h scan-technique. 4833 reflections were
measured in the range 2.50 6 h 6 29.96. 3478 were
assumed as observed applying the condition I > 2r(I).
Three reflections were measured every two hours as orien-
tation and intensity control, significant intensity decay was
not observed. Lorentz–polarisation but no absorption cor-
rections were made.
ments in acetone (between 1.1 and 2.7 Xꢀ1 cm2 molꢀ1
show the non-ionic behaviour of complexes 1–4 (conduc-
tivity values for non-electrolyte are below
)
a
100 Xꢀ1 cm2 molꢀ1 in acetone solution) [26,27]. The IR
spectra in the range 4000–400 cmꢀ1 show that the ligands
are coordinated to the Pd(II) or Pt(II). The (m(C@C),
m(C@N))ar bonds of the pyrazole ligand increase its fre-
quency when it is part of the complex. No significant
change is observed in the d(C–H)oop bands [19]. The IR
Table 2
Crystallographic data for cis-[PtCl2(L1)] (3)
Formula
M
Temperature (K)
Crystal system
Space group
Unit cell dimensions
C16H15Cl2N3Pt
515.30
293(2)
triclinic
spectra in the region 600–100 cmꢀ1
,
the m(M–N)
ꢀ
(M = Pd(II), Pt(II)) are observed (435, 425 for Pd(II) and
441, 433 cmꢀ1 for Pt(II)). Moreover, the spectra of com-
plexes 1, 2 display two bands (352, 330 cmꢀ1 for (1) and
357, 340 cmꢀ1 for (2)) corresponding to m(Pd–Cl), and for
complexes 3, 4 (349, 331 cmꢀ1 for (3) and 351, 339 cmꢀ1
for (4)) corresponding to m(Pt–Cl), which are typical for
compounds with a cis disposition of the chlorine ligands
around the Pd(II) and Pt(II), respectively [28].
P1 No. 2
˚
a (A)
9.028(3)
9.486(2)
10.872(9)
87.48(4)
80.11(5)
66.28(2)
893.4(8)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
U (A )
Z
1H NMR and 13C{1H} NMR spectra for complexes 1–4
were recorded in CDCl3 and show the signals of the coor-
dinated ligands. HMQC spectra were used to assign signals
Dcalc (g cmꢀ3
)
2.039
8.675
488
0.2 · 0.1 · 0.1
2.50–29.96
ꢀ12 < h < 12, ꢀ13 < k < 13, 0 < l < 15
4833/4833 [Rint = 0.0256]
4833/0/199
l (mmꢀ1
F(000)
)
1
of H and 13C spectra to most H and C atoms of com-
Crystal size
h Range (ꢁ)
Index range
Reflections collected/unique
Data/restraints/parameters
Goodness-of-fit
plexes. NMR data are reported in Section 2.
3.2. Crystal and molecular structure of [PdCl2(L2)] (2)
0.945
Final R1, xR2
R1 (all data), xR2
Residual electron density (e A
0.0375, 0.0823
0.0749, 0.0914
0.959 and ꢀ0.586
The crystal structure of complex 2 consists of discrete
cis-[PdCl2(L2)] molecules linked by van der Waals forces
(Fig. 2). The palladium centre has typical square planar
ꢀ3
˚
)

30
V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
Fig. 2. ORTEP drawing of the complex [PdCl2(L2)] (2) (ellipsoids are shown at the 50% probability level).
geometry (with a slight tetrahedral distortion) in which
the largest deviation from the mean coordination plane
The L2 ligand is not planar. The pyridyl and phenyl
groups are twisted with respect to the pyrazole ring. The
py–pz dihedral angle is 1.5(2)ꢁ, and the ph–pz is 69.2(3)ꢁ.
The py–pz dihedral angles is some other than the complex
[PdCl2(pz1)] (py–pz 1.43(4)ꢁ) [18], whereas the ph–pz angle
is higher than in the complex [PdCl2(pz1)] (ph–pz 0.48(3)ꢁ)
[18]. In comparison with the complex [PtCl2(L10)], the
angle py–pz angle is clearly lower that the py(coordi-
nated)–pz (6.5ꢁ), whereas the angle ph–pz in comparison
with py(non-coordinated)–pz is clearly higher (35.1ꢁ) [21].
The n-octyl group, which is bonded to the N(3) atom,
moves away from the chelating plane giving a torsion angle
N(2)–N(3)–C(15)–C(16) of 78.3(5)ꢁ, a value that is higher
than that of the [PtCl2(L10)] complex (65.7(6)ꢁ) [21].
˚
is ꢀ0.017(3) A (in N1), this distortion is lower than that
in [PtCl2(L10)] (L10 = 1-octyl-3,5-bis(2-pyridyl)pyrazole)
˚
(0.035 A) [21].
The metal atom is coordinated to one L2 via one pyra-
zole nitrogen, one pyridine nitrogen and two chlorine
ligands in a cis disposition. L2 behaves as a bidentate ligand
forming a five-membered metallocycle.
The [PdCl2(Npy)(Npz)] core (containing pyrazole and
pyridine nitrogen atoms and terminal chlorine ions) is
found in four complexes described in the literature
[18,29–31]. The bond distances Pd–Npy are of the some
order as those of Pd–Npz. The Pd–Npy, Pd–Npz and Pd–
Cl bond lengths in 2 are of the same order as those found
in the literature [18,29–31]. Table 3, selected bond distances
and angles for this complex.
3.3. Crystal and molecular structure of [PtCl2(L1)] (3)
The N(1)–Pd–N(2) bite angle, 79.39(13)ꢁ, is comparable
to those found in the structure with the ligand 3-phenyl-5-
(2-pyridyl)pyrazole (pz1), [PdCl2(pz1)], 79.16(14)ꢁ [18], but
lower than in Pt(II) complex with 1-octyl-3,5-bis(2-pyr-
idyl)pyrazole (L10), [PtCl2(L10)], 80.73(13)ꢁ [21].
The crystal structure of 3 consists of pairs of the cis-
[PtCl2(L1)] molecules linked by intermolecular forces
(Fig. 3). Selected bond distances and angles are given in
Table 4.
The L1 ligand chelates the platinum centre and two chlo-
rines atoms complete the four-coordinate environment of
the metal.
Table 3
2
˚
˚
Selected bond lengths (A) and bond angles (ꢁ) for cis-[PdCl2(L )] (2) with
The bond distances Pt–Npy (2.033(5) A) are clearly
estimated standard deviations (e.s.d.s) in parentheses
˚
longer than those of Pt–Npz (2.028(5) A). The Pt–Npy,
Pd–N(1)
Pd–N(2)
2.047(3)
2.047(3)
Pd–Cl(1)
Pd–Cl(2)
2.2714(16)
2.2934(16)
Pt–Npz, and Pt–Cl distances in 3 are in the usual range
found for other platinum complexes containing the analo-
gous ligands [32].
N(1)–Pd–N(2)
N(2)–Pd–Cl(1)
N(2)–Pd–Cl(2)
79.39(13)
172.37(10)
100.00(10)
N(1)–Pd–Cl(1)
N(1)–Pd–Cl(2)
Cl(1)–Pd–Cl(2)
93.04(10)
179.11(10)
87.58(6)
The chelating coordination of the L1 ligand to the plat-
inum atom forms a five-membered metallocycle ring has a

V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
31
Fig. 3. ORTEP drawing of the complex [PtCl2(L1)] (3) (ellipsoids are shown at the 50% probability level).
Table 4
It is interesting to note that the mononuclear complex is
organised in the crystal lattice in a bimolecular array held
by metal–p interactions. Pairs of stacked complexes,
related by an inversion centre, display Ptꢁ ꢁ ꢁperpendicular-
1
˚
Selected bond lengths (A) and bond angles (ꢁ) for cis-[PtCl2(L )] (3) with
estimated standard deviations (e.s.d.s) in parentheses
Pt–N(1)
Pt–N(2)
2.033(5)
2.028(5)
Pt–Cl(1)
Pt–Cl(2)
2.2969(18)
2.292(2)
˚
to-ring distance of 3.358 A. This plane-to-plane distance
N(1)–Pt–N(2)
N(2)–Pt–Cl(2)
N(1)–Pt–Cl(2)
78.83(19)
171.75(14)
93.52(15)
N(2)–Pt–Cl(1)
N(1)–Pt–Cl(1)
Cl(1)–Pt–Cl(2)
100.62(15)
178.62(14)
87.10(8)
is shorter than those found in other Pt(II) complexes con-
taining pyridyl or pyrimidyl ligands [33,34]. The Ptꢁ ꢁ ꢁring
˚
centroid is 3.811 A (Fig. 4). The spatial orientation of the
alkyl chain probably comes from steric effects between this
bulky group of the nitrogen electron pair N(1) of the pyr-
idine ring and the Cl(2) ligand. In fact, the alkylation of a
pyrazolic nitrogen of the 3-phenyl-5-(2-pyridyl)pyrazole
(pz2) ligand was made with the purpose of increasing the
solubility of transition metal complexes. The crystal struc-
ture of 3 reveals that this functionalisation prevents the for-
mation of solid infinite linear stacking chains but allows the
stacking of pairs of molecules. This behaviour is similar to
the [PtCl2(L2)] complex [21].
bite angle of N(1)–Pt–N(2) (78.83(9)ꢁ), the largest devia-
˚
tion from the mean coordination plane is 0.04(5) A (in
N1), and this distortion is higher that in [PdCl2(L2)]
10
˚
˚
(ꢀ0.0165 A), and [PtCl2(L )] (0.035 A) [21].
The [PtCl2(Npy)(Npz)] core (containing pyrazole and
pyridine nitrogen atoms and terminal chlorine atoms) is
found in one complex described in the literature [21].
The L1 ligand is not planar. The pyridyl and phenyl
groups are twisted with respect to the pyrazole ring.
Whereas the pyridyl group is slightly twisted (py–pz dihe-
dral angle 3.4(4)ꢁ), the phenyl group shows a significant
torsion with respect to pyrazole (ph–pz dihedral angle
54.0(4)ꢁ). The py–pz dihedral angle is higher than the com-
plex [PdCl2(L2)] and the ph–pz dihedral angle is lower that
in complex [PdCl2(L2)].
3.4. Reactivity of [PdCl2(L)] (L = L1, L2) towards L (L1,
L2), pyridine (py) and triphenylphosphine (PPh3)
Treatment of [PdCl2(L)] (L = L1, L2) with AgBF4 and
NaBPh4 in the presence of ligand (L1, L2), pyridine (py)
or triphenylphosphine (PPh3) yielded [Pd(L)2](BPh4)2
(L = L1 (5), L2 (6)), [Pd(L)(py)2](BPh4)2 (L = L1 (7), L2
(8)), and [Pd(L)(PPh3)2](BPh4)2 (L = L1 (9), L2 (10))
(Scheme 1). These proposed formulas were corroborated
by elemental analyses. Conductivity in acetone for comple-
xes [5]–[10](BPh4)2 (between 163.1 and 176.5) is in agreement
The ethyl group, which is bonded to the N(3) atom,
moves away from the chelating plane, giving a torsion
angle of N(2)–N(3)–C(15)–C(16) of 80.8(8)ꢁ, a value that
is higher than that of [PdCl2(L2)], 78.28ꢁ and [PtCl2(L10)],
65.7(6)ꢁ [21].

32
V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
Fig. 4. Ortep drawing of the complex [PtCl2(L1)] (3), viewed in projection along the staking axis. Hydrogen atoms are not shown.
2+
N
N
N
R
Pd
N
N
N
R
1 L, 2 AgBF4
-
AgCl
2+
N
N
N
N
Pd
N
N
R
Cl
Pd
N
R
N
Cl
2 py,
-
2 AgBF4
1
2 AgBF4
PPh3
,
AgCl
-
AgCl
2+
N
N
N
Pd
R
Ph3P
PPh3
Scheme 1.

V. Montoya et al. / Inorganica Chimica Acta 359 (2006) 25–34
33
with 2:1 electrolytes. The range of conductivity values for
10ꢀ3 M solutions of 2:1 electrolyte compounds in acetone
is between 160 and 200 Xꢀ1 cm2 molꢀ1 [26,27]. The positive
ionisation spectra ([5]–[10](BPh4)2) complexes gave peaks
with values of 604 (44%) [5]2+, 772 (9%) [6]2+, 537 (12%)
[7]2+, 622 (8%) [8]2+ (molecular peaks of the cation). In
the spectra of [9]2+ and [10]2+, the molecular peaks 879
and 963, respectively, were observed in an intensity lower
than 1%. But the ES(+)MS does show many fragmentation
peaks, thus confirming the existence of the species.
IR spectra of [5]–[6](BPh4)2, the bands (m(C@C),
m(C@N))ar and d(C–H)oop again decrease the frequency
with respect to the free ligands [19] and also with respect
to the dichlorocomplexes.
observed. The presence of a pendant alkyl arm in the ligands
increases significantly the solubility of complexes in organic
solvents, which is essential in homogeneous catalysis.
5. Supplementary material
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic Data
Centre, CCDC reference number 266676 for compound
[PdCl2(L2)] (2) and 266677 for compound [PtCl2(L1)] (3).
Copies of this information may be obtained free of charge
from The Director, CCDC, 12 Union Road, Cambridge,
CB2 1EZ, UK (fax: +44 1223 336 033; e-mail: deposit@
ccdc.cam.ac.uk or www: htpp://www.ccdc.cam.ac.uk).
IR spectra of [7]–[8](BPh4)2 presents a bands attribut-
able to (m(C@C)py, m(C@N)py), and (d(C@C)py, d(C@N)py)
at 1611 and 1451 cmꢀ1, respectively. IR spectra of [5]–
[10](BPh4)2 present bands that were assigned to m(B–C) at
Acknowledgement
Support by the Spanish Ministerio de Educacio´n y Cultura
(Project BQU2003-03582) is gratefully acknowledgement.
612 cmꢀ1
.
The IR spectra of the complexes between 600 and
100 cmꢀ1 region were also studied [28,35]. In all cases, they
show bands attributable to m(Pd–N) between 449 and
471 cmꢀ1. Bands attributable to m(Pd–P) at 341 cmꢀ1 for
[9](BPh4)2 and 344 cmꢀ1 for [10](BPh4)2 were also assigned.
1H NMR and 13C{1H} NMR spectra for complexes [5]–
[10](BPh4)2 were recorded in CDCl3 and CD2Cl2, respec-
tively. 1H and 13C{1H} NMR spectra corroborate the
obtaining of these complexes. HMQC spectra were used
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