New mono- and bis(pentafluorophenyl)palladium(II) complexes with iminophosphine ligands. Crystal structure of [Pd(C6F5)(SC6H5)(ο-Ph 2PC6H4-CH=NiPr)]

Article abstract of DOI:10.1016/S0277-5387(00)00659-8

The synthesis of new mono- and bis(pentafluorophenyl) derivatives of palladium(II) with the mixed-donor bidentate ligands ο-Ph₂PC₆H₄-CH=NR (RN-P) has been achieved. The new complexes of general formula [Pd(C₆F₅)₂(RN-P)] [R = Me (1), Et (2), ⁿPr (3) ⁱPr (4), ^tBu (5), Ph (6), NH-Me (7)] and [Pd (C₆F₅)Cl(RN-P)] [R = Me (8), ⁱPr (9), NH-Me (10)] have been, respectively, prepared by reaction between the labile precursors cis-[Pd(C₆F₅)₂(PhCN)₂] or [{Pd(C₆F₅)(tht)(μ-CL)}₂] (tht= tetrahydrothiophene) and the corresponding iminophosphines. Complex (9) undergoes metathetical exchange of chloride with anionic monodentate ligands when reacting with alkaline salts, giving the complexes of formula [Pd(C₆F₅)X(ⁱPrN-P)] [X = Br (11), I (12), CN (13), SCN (14), SC₆H₅ (15), p-SC₆H₄Me (16), p-SC₆H₄NO₂ (17), OMe (18)]. Furthermore, when the chloropentafluorophenyl complex (9) was treated with silver trifluoromethanesulfonate in the presence of tertiary phosphines, the cationic derivatives [Pd(C₆F₅)(L)(ⁱPrN-P)](CF₃SO ₃) [L = PEt₃ (19), PMe₂Ph (20), PMePh₂ (21)] were obtained in good yield. The new complexes were characterized by partial elemental analyses and spectroscopic methods (IR, ¹H, ¹⁹F and ³¹P NMR). The molecular structure of complex (15) has been determined by a single-crystal diffraction study, showing that the iminophosphine act as chelating ligand with coordination around the palladium atom slight distorted from the square-planar geometry.

Full text of DOI:10.1016/S0277-5387(00)00659-8

Polyhedron 20 (2001) 571–578
www.elsevier.nl/locate/poly
New mono- and bis(pentafluorophenyl)palladium(II) complexes
with iminophosphine ligands. Crystal structure of
[Pd(C6F5)(SC6H5)(o-Ph2PC6H4–CHꢀNiPr)]
Gregorio Sa´nchez a,*, Jose´ L. Serrano b, Francisca Momblona a, Francisco Ruiz a,
Joaqu´ın Garc´ıa a, Jose´ Pe´rez b, Gregorio Lo´pez a, Penny A. Chaloner c,
Peter Hitchcock c
a Departamento de Qu´ımica Inorga´nica, Uni6ersidad de Murcia, 30071 Murcia, Spain
b
´
Departamento de Ingenier´ıa Minera, Geolo´gica y Cartogra´fica, Area de Qu´ımica Inorga´nica, 30203 Cartagena, Spain
c School of Chemistry, Physics and En6ironmental Science, Uni6ersity of Sussex, Brighton, BN1 9QJ, UK
Received 30 October 2000; accepted 8 December 2000
Abstract
The synthesis of new mono- and bis(pentafluorophenyl) derivatives of palladium(II) with the mixed-donor bidentate ligands
o-Ph2PC6H4–CHꢀNR (RN–P) has been achieved. The new complexes of general formula [Pd(C6F5)2(RN–P)] [R=Me (1), Et (2),
i
t
i
nPr (3) Pr (4), Bu (5), Ph (6), NH–Me (7)] and [Pd (C6F5)Cl(RN–P)] [R=Me (8), Pr (9), NH–Me (10)] have been, respectively,
prepared by reaction between the labile precursors cis-[Pd(C6F5)2(PhCN)2] or [{Pd(C6F5)(tht)(m-Cl)}2] (tht=tetrahydrothiophene)
and the corresponding iminophosphines. Complex (9) undergoes metathetical exchange of chloride with anionic monodentate
ligands when reacting with alkaline salts, giving the complexes of formula [Pd(C6F5)X(iPrN–P)] [X=Br (11), I (12), CN (13),
SCN (14), SC6H5 (15), p-SC6H4Me (16), p-SC6H4NO2 (17), OMe (18)]. Furthermore, when the chloropentafluorophenyl complex
(9) was treated with silver trifluoromethanesulfonate in the presence of tertiary phosphines, the cationic derivatives
[Pd(C6F5)(L)(iPrN–P)](CF3SO3) [L=PEt3 (19), PMe2Ph (20), PMePh2 (21)] were obtained in good yield. The new complexes were
1
characterized by partial elemental analyses and spectroscopic methods (IR, H, 19F and 31P NMR). The molecular structure of
complex (15) has been determined by a single-crystal diffraction study, showing that the iminophosphine act as chelating ligand
with coordination around the palladium atom slight distorted from the square-planar geometry. © 2001 Elsevier Science B.V. All
rights reserved.
Keywords: Chelate complexes; Pentafluorophenyl palladium derivatives; Iminophosphines; Crystal structures
cursors in catalytic processes [9–16]. Thus, it has been
found that some complexes with N–P ligands are suit-
1. Introduction
able for palladium-catalyzed allylic alkylation [17],
During the last few years there has been a growing
oligomerization of olefins [18,19], homogeneous hydro-
interest in the chemistry of polydentate ligands with
genation of double and triple C–C bonds [20] and
both hard and soft donor atoms [1–7]. The metal
copolymerization of CO/olefins [21–23]. Among the
complexes with N and P donor atoms display a variety
most widely studied ligands with these characteristics
of coordination modes well beyond those of P–P or
are the pyridylphosphines and the iminophosphines
N–N ligands [8]. Furthermore, these ligands show par-
that we present in this work, from which palladium
ticular behaviour binding soft metal centres such as
complexes have been profusely reported since 1992
Pd(II) and Pt(II) that make their complexes good pre-
[13–17,24–29]. In this sense, we have described in
recent work the syntheses of some organometallic
derivatives containing iminophosphine ligands, either
* Corresponding author. Tel.: +34-68-307-100; fax: +34-68-364-
148.
with an ortho-metalated palladium (II) backbone [30]
E-mail address: gsg@um.es (G. Sa´nchez).
0277-5387/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0277-5387(00)00659-8

572
G. Sa´nchez et al. / Polyhedron 20 (2001) 571–578
or accompanying a bis(pentafluorophenyl)nickel (II)
fragment [31] as a result of directly reacting the precur-
sor cis-[Ni(C6F5)2(PhCN)2] with the corresponding
ligands.
[Pd(C6F5)2(o-Ph2PC6H4–CHꢀNMe)] (1) was ob-
tained in 80% yield (80 mg). Anal. Calc. for
C32F10H18NPPd: C, 51.7; H, 2.4; N, 1.9. Found: C,
51.9; H, 2.4; N, 1.9%. IR (Nujol, cm−1): 1644 (C=N
str). 1H NMR (CDCl3) l: 3.4 (s, 3H, Me); 7.5 (m,
11H); 7.7 (m, 3H); 8.5 (s, 1H, CHꢀN). 19F NMR
(CDCl3) l: –114.2 (d, 2Fo, Jom=27.7); –115.3 (m,
2Fo); –162.5 (t, 1Fp, Jpm=19.8); −164.4 (m, 1Fp+
2Fm); –165.6 (m, 2Fm). 31P NMR (CDCl3) l: 26.0 (s).
[Pd(C6F5)2(o-Ph2PC6H4–CHꢀNEt)] (2) was obtained
in 80% yield (78 mg). Anal. Calc. for C33F10H20NPPd:
C, 52.3; H, 2.7; N, 1.9. Found: C, 52.0; H, 2.5; N, 1.8%.
Here we report the preparation of new mono- and
bis(pentafluorophenyl) derivatives of palladium(II) with
iminophosphine ligands by means of the ligand-ex-
change reaction between the labile complexes
[{Pd(C6F5)(tht)(m-Cl)}2] [30] and cis-[Pd(C6F5)2-
(PhCN)2] [33], well known as convenient precursors for
the synthesis of pentafluorophenyl compounds [34,35],
and iminophosphines. Further reactivity of the complex
[Pd (C6F5)Cl(iPrN–P)] towards interchange of chloride
to give neutral and cationic derivatives has also been
investigated.
1
IR (Nujol, cm−1): 1634 (CꢀN str). H NMR (CDCl3)
l: 1.2 (t, 3H, CH3); 3.5 (q, 2H, CH2, JHH=7.1); 7.4 (m,
11H); 7.8 (m, 3H); 8.5 (s, 1H, CHꢀN). 19F NMR
(CDCl3) l: –114.2 (d, 2Fo, Jom=27.4); –115.0 (m,
2Fo); –162.5 (t, 1Fp, Jom=19.8); –164.4 (m, 1Fp+
2Fm); –165.5 (m, 2Fm). 31P NMR (CDCl3) l: 25.6 (s).
[Pd(C6F5)2(o-Ph2PC6H4–CHꢀNnPr)] (3) was ob-
tained in 84% yield (83 mg). Anal. Calc. for
C34F10H22NPPd: C, 52.9; H, 2.9; N, 1.8. Found: C,
52.8; H, 2.8; N, 2.0%. IR (Nujol, cm−1): 1632 (CꢀN
2. Experimental
2.1. Materials and physical measurements
C, H, N and S analyses were carried out with a
Perkin–Elmer 240C microanalyser. IR spectra were
recorded on a Perkin–Elmer spectrophotometer 16F
PC FT-IR, using Nujol mulls between polyethylene
sheets. NMR data were recorded on a Bruker AC 200E
(1H) or a Varian Unity 300 (1H, 19F, 31P{1H}) spec-
trometer using as standards SiMe4, CFCl3 and H3PO4,
respectively. Conductance measurements were per-
formed with a Crison 525 conductimeter (in acetone,
5×10−4 M).
1
str). H NMR (CDCl3) l: 0.5 (t, 3H, CH3, JHH=7.3);
1.8 (m, 2H, CH2); 2.8 (m, 2H, CH2N); 7.5 (m, 11H); 7.8
(m, 3H); 8.5 (s, 1H, CH=N). 19F NMR (CDCl3) l:
–114.1 (d, 2Fo, Jom=28.2); –115.2 (m, 2Fo); –162.4 (t,
1Fp, Jpm=19.8); –164.3 (m, 1Fp+2Fm); –165.5 (m,
2Fm). 31P NMR (CDCl3) l: 25.2 (s).
[Pd(C6F5)2(o-Ph2PC6H4–CHꢀNiPr)] (4) was obtained
in 90% yield (89 mg). Anal. Calc. for C34F10H22NPPd:
C, 52.9; H, 2.9; N, 1.8. Found: C, 52.9; H, 2.9; N, 1.9%.
1
IR (Nujol, cm−1): 1632 (C=N str). H NMR (CDCl3)
The pentafluorophenyl precursors [{Pd(C6F5)(tht)(m-
Cl)}2] and cis-[Pd(C6F5)2(PhCN)2] were prepared by the
published methods [32,33]. The iminophosphine ligands
were prepared according to reported procedures [11]
and all the solvents were dried by standard methods
before use.
l: 1.1 (d, 6H, CH3, JHH=6.5); 3.8 (sep, 1H, CH); 7.4
(m, 11H); 7.6 (m, 1H); 7.8 (m, 1H); 8.0 (m, 1H); 8.5 (s,
1H, CH=N). 19F NMR (CDCl3) l: –114.2 (m, 2Fo);
–115.0 (m, 2Fo); –162.6 (t, 1Fp, Jpm=20.0); –164.4 (m,
1Fp+2Fm); –165.6 (m, 2Fm). 31P NMR (CDCl3) l:
26.5 (s).
[Pd(C6F5)2(o-Ph2PC6H4–CHꢀNtBu)] (5) was ob-
tained in 86% yield (87 mg). Anal. Calc. for
C35F10H24NPPd: C, 53.5; H, 3.1; N, 1.8. Found: C,
53.7; H, 3.0; N, 1.8%. IR (Nujol, cm−1): 1632 (CꢀN
str). 1H NMR (CDCl3) l: 1.0 (s, 9H, CH3); 7.2 (m, 2H);
7.5 (m, 10H); 7.9 (m, 1H); 8.0 (m, 1H); 8.5 (d, 1H,
CHꢀN, JHP=3.1). 19F NMR (CDCl3) l: –113.5 (br,
2Fo); –116.1 (br, 2Fo); –162.8 (t, 1Fp, Jpm=19.8);
–164.2 (t, 1Fp, Jpm=19.8); –165.6 (m, 4Fm). 31P NMR
(CDCl3) l: 28.0 (s).
2.2. Preparation of the complexes [Pd(C6F5)2(RNP)]
[R=Me (1), Et (2), Pr (3) Pr (4), Bu (5), Ph (6),
NH–Me (7)]
n
i
t
The complexes were obtained by treating
[Pd(C6F5)2(PhCN)2] with the corresponding iminophos-
phine (molar ratio 1:1) in acetone according to the
following general method. To an acetone (5 ml) solu-
tion of the precursor [Pd(C6F5)2(PhCN)2] (0.07 g, 0.129
mmol) was added the calculated amount of iminophos-
phine in acetone solution previously prepared. The
reaction was stirred at room temperature for 30 min.
Upon complete solvent evaporation, the crude product
was precipitated with hexane/iPrOH and then filtered
off, washed with hexane and air dried. Yellow crystals
of the compounds 1–7 were obtained in high yield by
recrystallization from dichloromethane–hexane.
[Pd(C6F5)2(o-Ph2PC6H4–CHꢀNPh)] (6) was obtained
in 90% yield (93 mg). Anal. Calc. for C37F10H20NPPd:
C, 55.1; H, 2.5; N, 1.7. Found: C, 54.9; H, 2.4; N, 1.9%.
1
IR (Nujol, cm−1): 1602 (CꢀN str). H NMR (CDCl3)
l: 7.4 (m, 19H); 8.6 (d, 1H, CHꢀN, JHP=3.2). 19F
NMR (CDCl3) l: –114.2 (d, 2Fo, Jom=30.0); –115.0
(m, 2Fo); –162.7 (t, 1Fp, Jpm=19.8); –164.4 (m, 1Fp+
2Fm); –165.6 (m, 2Fm). 31P NMR (CDCl3) l: 23.6 (s).

G. Sa´nchez et al. / Polyhedron 20 (2001) 571–578
573
[Pd(C6F5)2(o-Ph2PC6H4–CHꢀNNHMe)] (7) was ob-
2.4. Preparation of the complexes
[Pd(C6F5)X(iPrN–P)] [X=Br (11), I (12), CN (13),
tained in 89% yield (87 mg). Anal. Calc. for
C32F10H19N2PPd: C, 50.6; H, 2.5; N, 3.7. Found: C,
50.8; H, 2.4; N, 1.9%. IR (Nujol, cm−1): 3420 (N–H),
SCN (14), SC6H5 (15), p-SC6H4Me (16), p-SC6H4NO2
(17), OMe (18)]
1
1632 (CꢀN str). H NMR (CDCl3) l: 3.0 (d, 3H, Me,
J
HH=3.9); 7.5 (m, 10H); 7.7 (m, 4H); 8.2 (d, 1H,
Compounds 11–14 were obtained by reacting stoi-
chiometric amounts (1:1) of complex 9 and the corre-
sponding potassium salt KX in 10 ml of acetone. After
2 h stirring at boiling temperature the KCl formed was
removed by filtration and the resulting solution concen-
trated under reduced pressure to half volume. The
addition of hexane caused precipitation of the new
complexes, which were filtered off and air-dried.
CHꢀN, JHP=5.0). 19F NMR (CDCl3) l: –114.2 (d,
2Fo, Jom=30.5); –114.5 (m, 2Fo); –162.4 (t, 1Fp,
J
pm=19.8); –164.4 (t, 1Fp, Jpm=19.8); –164.5 (m,
2Fm); –165.6 (m, 2Fm). 31P NMR (CDCl3) l: 30.4 (s).
2.3. Preparation of the complexes [Pd(C6F5)Cl(RN–P)]
i
[R=Me (8), Pr (9), NH–Me (10)]
[Pd(C6F5)Br(o-Ph2PC6H4–CHꢀNiPr)] (11) was ob-
tained in 70% yield. Anal. Calc. for C28BrF5H22NPPd:
C, 49.1; H, 3.2; N, 2.0. Found: C, 49.2; H, 3.1; N, 2.2%.
The complexes were obtained by treating
[{Pd(C6F5)(tht)(m-Cl)}2]
with
the
corresponding
1
IR (cm−1): 1632 (CꢀN str). H NMR (CDCl3): 1.2 (d,
iminophosphine (molar ratio 1:2) in dichloromethane
according to the following general method. To a
dichloromethane (5 ml) solution of the precursor
[{Pd(C6F5)(tht)(m-Cl)}2] (0.068 g, 0.086 mmol) was
added the calculated amount of iminophosphine in
dichloromethane solution previously prepared. The re-
action was stirred at room temperature for 2 h. The
white solution was concentrated under reduced pressure
to half volume and the addition of hexane caused
precipitation of the new complexes, which were filtered
off and air-dried. White crystals of the compounds were
obtained in high yield by recrystallization from
dichloromethane–hexane.
6H, CH3, JHH=6.5); 5.4 (sep, 1H, CH); 7.4 (m, 14H,
aromatic); 8.0 (s, 1H, CHꢀN). 19F NMR (CDCl3):
–115.7 (d, 2Fo, Jom=24.5); –162.1 (t, 1Fp, Jpm=19.2);
–163.9 (m, 2Fm). 31P NMR (CDCl3): 29.6 (br).
[Pd(C6F5)I(o-Ph2PC6H4–CHꢀNiPr)] (12) was ob-
tained in 68% yield. Anal. Calc. for C28IF5H22NPPd: C,
45.9; H, 3.0; N, 1.9. Found: C, 45.7; H, 3.1; N, 1.7%.
1
IR (cm−1): 1628 (CꢀN str). H NMR (CDCl3): 1.2 (d,
6H, CH3, JHH=6.5); 5.4 (sep, 1H, CH); 7.4 (m, 14H,
aromatic); 8.0 (s, 1H, CHꢀN). 19F NMR (CDCl3):
–113.8 (d, 2Fo, Jom=23.1); –162.3 (t, 1Fp, Jpm=20.3);
–164.0 (m, 2Fm). 31P NMR (CDCl3): 25.8 (br).
[Pd(C6F5)Cl(o-Ph2PC6H4–CHꢀNMe)] (8) was ob-
tained in 90% yield (94 mg). Anal. Calc. for
C26ClF5H18NPPd: C, 60.0; H, 2.9; N, 2.3. Found: C,
59.9; H, 2.9; N, 2.3%. IR (Nujol, cm−1): 1634 (CꢀN
[Pd(C6F5)(CN)(o-Ph2PC6H4–CHꢀNiPr)] (13) was ob-
tained in 75% yield. Anal. Calc. for C29F5H22N2PPd: C,
55.2; H, 3.5; N, 4.4. Found: C, 55.0; H, 3.2; N, 4.3%.
IR (cm−1): 2350 (CN str), 1634 (CꢀN str). H NMR
1
1
str). H NMR (CDCl3) l: 3.9 (s, 3H, Me); 7.4 (m, 14H,
(CDCl3): 1.3 (d, 6H, CH3, JHH=6.5); 5.8 (sep, 1H,
CH); 7.4 (m, 14H, aromatic); 8.0 (s, 1H, CHꢀN). 19F
NMR (CDCl3): –115.4 (d, 2Fo, Jom=22.0); –161.8 (t,
1Fp, Jpm=20.3); –163.8 (m, 2Fm). 31P NMR (CDCl3):
25.8 (br).
aromatic); 8.0 (s, 1H, CHꢀN). 19F NMR (CDCl3) l:
–116.6 (dd, 2Fo, Jom=21.4); –161.8 (t, 1Fpm, J=19.2);
–163.8 (m, 2Fm). 31P NMR (CDCl3) l: 31.3 (t, JPF
=
11.9).
[Pd(C6F5)Cl(o-Ph2PC6H4–CHꢀNiPr)] (9) was ob-
tained in 85% yield (93 mg). Anal. Calc. for
C28ClF5H22NPPd: C, 52.5; H, 3.4; N, 2.2. Found: C,
52.7; H, 3.5; N, 2.2%. IR (Nujol, cm−1): 1632 (CꢀN
[Pd(C6F5)(SCN)(o-Ph2PC6H4–CHꢀNiPr)] (14) was
obtained
in
90%
yield.
Anal.
Calc.
for
C29F5H22N2PSPd: C, 52.5; H, 3.3; N, 4.2; S, 4.8.
Found: C, 52.3; H, 3.2; N, 4.36; S, 4.8%. IR (cm−1):
1
str). H NMR (CDCl3) l: 1.2 (d, 6H, CH3, JHH=6.5);
1
2078 (CN str), 1640 (CꢀN str). H NMR (CDCl3): 1.3
5.3 (sep, 1H, CH); 7.4 (m, 14H, aromatic); 8.0 (s, 1H,
CHꢀN). 19F NMR (CDCl3) l: –116.4 (d, 2Fo, Jom
=
(d, 6H, CH3, JHH=6.5); 4.7 (sep, 1H, CH); 7.4 (m,
14H, aromatic); 8.1 (s, 1H, CHꢀN). 19F NMR (CDCl3):
–117.4 (d, 2Fo, Jom=24.0); –160.7 (t, 1Fp, Jpm=19.5);
–163.2 (m, 2Fm). 31P NMR (CDCl3): 31.8 (br).
24.5); –162.0 (t, 1Fp, Jpm=19.2); –163.8 (m, 2Fm). 31P
NMR (CDCl3) l: 30.6 (t, JPF=11.0).
[Pd(C6F5)Cl(o-Ph2PC6H4–CHꢀNNHMe)] (10) was
obtained in 85% yield (91 mg). Anal. Calc. for
C26ClF5H19N2PPd: C, 49.8; H, 3.0; N, 4.5. Found: C,
49.6; H, 3.1; N, 4.4%. IR (Nujol, cm−1):1634 (CꢀN
To obtain complexes 15–17 the corresponding thiol
(0.062 mmol) was first reacted with a 10 ml solution of
MeONa/MeOH for 15 min. Complex 9 (0.062 mmol)
was then added and the mixture was stirred at room
temperature for 1 h. Concentration of the resulting
solution under reduced pressure to half volume precipi-
tated the yellow solids that were filtered off, washed
with diethyl ether and air-dried.
1
str). H NMR (CDCl3) l: 2.9 (s, 3H, Me); 7.3 (m, 14H,
aromatic); 8.5 (d, 1H, CHꢀN, JPH=4.0). 19F NMR
(CDCl3) l: –116.8 (d, 2Fo, Jom=21.4); –161.6 (t, 1Fp,
J
pm=20.0); –163.6 (m, 2Fm). 31P NMR (CDCl3) l:
30.8 (t, JPF=11.4).

574
G. Sa´nchez et al. / Polyhedron 20 (2001) 571–578
[Pd(C6F5)(SC6H5)(o-Ph2PC6H4–CHꢀNiPr)] (15) was
trated under reduced pressure to half volume and the
addition of hexane caused precipitation of the new
complexes, which were filtered off and air-dried. White
crystals of the compounds were obtained by recrystal-
lization from dichloromethane–hexane.
obtained in 70% yield (31 mg). Anal. Calc. for
C34F5H27NPSPd: C, 57.2; H, 3.8; N, 1.9; S, 4.5. Found:
C, 57.4; H, 3.6; N, 1.9; 4.7%. IR (Nujol, cm−1): 1632
(CꢀN str). 1H NMR (CDCl3) l: 1.1 (d, 6H, CH3,
[Pd(C6F5)(PEt3)(o-Ph2PC6H4–CHꢀNiPr)][TfO] (19)
was obtained in 75% yield (47 mg). Anal. Calc. for
C35F8H37NO3P2SPd: C, 48.2; H, 4.2; N, 1.6; S, 3.7.
Found: C, 48.0; H, 4.5; N, 1.7; 4.0%. IR (Nujol, cm−1):
1634 (CꢀN str), 760 (PEt3). \M=123 V−1 mol−1 cm2.
1H NMR (CDCl3) l: 1.0 (m, 6H, PCH2); 1.2 (d, 6H,
J
HH=6.5); 5.1 (m, 1H, CH); 7.1 (m, 19H, aromatic);
8.0 (s, 1H, CHꢀN). 19F NMR (CDCl3) l: –115.3 (d,
2Fo, Jom=30.7); –163.6 (t, 1Fp, Jpm=20.3); –164.4 (m,
2Fm). 31P NMR (CDCl3) l: 24.3 (s).
[Pd(C6F5)(SC6H4Me)(o-Ph2PC6H4–CHꢀNiPr)] (16)
was obtained in 75% yield (34 mg). Anal. Calc. for
C35F5H29NPSPd: C, 57.8; H, 4.0; N, 1.9; S, 4.4. Found:
C, 58.0; H, 3.7; N, 1.7; 4.2%. IR (Nujol, cm−1): 1628
(CꢀN str). 1H NMR (CDCl3) l: 1.2 (d, 6H, CH3,
i
iPr, JHH=6.4); 1.6 (m, 9H, CH3); 4.0 (m, 1H, Pr); 7.8
(m, 14H, aromatic); 8.6 (s, 1H, CHꢀN). 19F NMR
(CDCl3) l: –114.7 (m, 2Fo); –158.5 (t, 1Fp, Jpm
=
J
HH=6.5); 2.1 (s, 3H, Me); 5.1 (sep, 1H, CH); 7.1 (m,
19.2); –160.9 (m, 2Fm). 31P NMR (CDCl3) l: 16.4 (d,
PA, PEt3); 24.3 (d, PB, JAB=405.2).
18H, aromatic); 8.0 (s, 1H, CH=N). 19F NMR
(CDCl3) l: –115.5 (d, 2Fo, Jom=25.0); –164.2 (t, 1Fp,
[Pd(C6F5)(PMePh2)(o-Ph2PC6H4–CHꢀNiPr)][TfO]
(20) was obtained in 78% yield (48 mg). Anal. Calc. for
C42F8H35NO3P2SPd: C, 52.9; H, 3.7; N, 1.5; S, 3.4.
Found: C, 52.8; H, 3.7; N, 1.3; 3.4%. IR (Nujol, cm−1):
1634 (CꢀN str), 892 (PMePh2). \M=135 V−1 mol−1
J
pm=20.3); –164.7 (m, 2Fm). 31P NMR (CDCl3) l:
24.1 (s).
[Pd(C6F5)(SC6H4NO2)(o-Ph2PC6H4–CHꢀNiPr)] (17)
was obtained in 70% yield (33 mg). Anal. Calc. for
C34F5H26N2O2PSPd: C, 53.8; H, 3.4; N, 3.7; S, 4.2.
Found: C, 54.2; H, 3.2; N, 3.9; 4.2%. IR (Nujol, cm−1):
1
i
cm2. H NMR (CDCl3) l: 0.9 (d, 6H, Pr, JHH=6.4);
i
1
1.7 (d, 6H, PMe2, JPH=9.9); 3.8 (sep, 1H, Pr); 7.6 (m,
1634 (CꢀN str), 1568 (NO). H NMR (CDCl3) l: 1.0
19H, aromatic); 8.5 (s, 1H, CHꢀN). 19F NMR (CDCl3)
(d, 6H, CH3, JHH=6.5); 5.0 (sep, 1H, CH); 7.5 (m,
18H, aromatic); 8.1 (d, 1H, CHꢀN, JPH=8.6). 19F
NMR (CDCl3) l: –115.2 (d, 2Fo, Jom=28.8); –161.4
(t, 1Fp, Jpm=22.3); –163.7 (m, 2Fm). 31P NMR
(CDCl3) l: 25.8 (s).
l: −114.6 (d, 2Fo, Jom=21.4); –159.8 (t, 1Fp, Jpm
=
19.2); –161.3 (m, 2Fm). 31P NMR (CDCl3) l: 7.3 (d,
PA, PMe2Ph); 25.6 (d, PB, JAB=419.4).
[Pd(C6F5)(PMe2Ph)(o-Ph2PC6H4–CHꢀNiPr)][TfO]
(21) was obtained in 82% yield (47 mg). Anal. Calc. for
C37F8H33NO3P2SPd: C, 49.8; H, 3.7; N, 1.6; S, 3.6.
Found: C, 49.9; H, 3.9; N, 1.6; 3.7%. IR (Nujol, cm−1):
1632 (CꢀN str), 914 (PMe2Ph). \M=115 V−1 mol−1
[Pd(C6F5)(OCH3)(o-Ph2PC6H4–CHꢀNiPr)] (18) was
obtained in 80% yield (31 mg) by treating a 5 ml
solution of complex 9 (0.062 mmol) in methanol with a
KOH/MeOH solution (10 ml). The mixture was then
stirred at room temperature for 1 h. Addition of hexane
caused the precipitation of a white solid that was
filtered off, washed with diethyl ether and air-dried.
Anal. Calc. for C29F5H25NOPPd: C, 54.8; H, 3.9; N,
2.2. Found: C, 54.5; H, 3.8; N, 2.4%. IR (Nujol, cm−1):
1
i
cm2. H NMR (CDCl3) l: 0.9 (d, 6H, Pr, JHH=6.5);
i
2.2 (d, 3H, PMe, JPH=9.0); 3.8 (sep, 1H, Pr); 7.4 (m,
24H, aromatic); 8.6 (s, 1H, CHꢀN). 19F NMR (CDCl3)
l: –115.2 (m, 2Fo); –158.8 (t, 1Fp, Jpm=23.0); –160.8
(m, 2Fm). 31P NMR (CDCl3) l: 5.8 (d, PA, PMePh2);
25.0 (d, PB, JAB=421.4).
1
1632 (CꢀN str). H NMR (CDCl3) l: 1.2 (d, 6H, CH3,
J
HH=6.5); 3.4 (s, 3H, OMe); 5.4 (sep, 1H, CH); 7.4 (m,
14H, aromatic); 8.0 (s, 1H, CH=N). 19F NMR
(CDCl3) l: –115.2 (d, 2Fo, Jom=21.5); –161.4 (t, 1Fp,
2.6. Crystal structure determination of
[Pd(C6F5)(SC6H5)(o-Ph2PC6H4–CHꢀNiPr)] (15)
J
pm=19.2); –163.7 (m, 2Fm). 31P NMR (CDCl3) l:
30.3 (s).
X-ray experiment was carried out on an Enraf Non-
ius CAD4 diffractometer using a graphite monochro-
mated Mo Ka radiation. The crystallographic data are
shown in Table 1. An empirical „-scan mode absorp-
tion correction was made.
2.5. Preparation of the complexes
[Pd(C6F5)(L)(iPrN–P)](CF3SO3) [L=PEt3 (19),
PMe2Ph (20), PMePh2 (21)]
Data for 15 were collected using a single crystal of
approximate dimensions 0.4×0.4×0.2 mm3. The
range of hkl was 05h516, 05k513, –175l516
corresponding to 2[max=44°. The structure was solved
by direct methods SHELXS-97 [36] and refined on F2 by
full-matrix least-squares techniques [36] on F2 using
anisotropic thermal parameters for non-H atoms.
The complexes were obtained according to the fol-
lowing general method. To a dichloromethane (5 ml)
solution of complex 9 (0.065 mmol) was added the
stoichiometric amount (1:1) of silver triflate and the
corresponding phosphine. The reaction was stirred at
room temperature for 1 h and then filtered to remove
the AgCl formed. The resulting solution was concen-

G. Sa´nchez et al. / Polyhedron 20 (2001) 571–578
575
3. Results and discussion
tions to give the corresponding neutral square-planar
complexes [Pd(C6F5)2(RN–P)] shown in Scheme 1.
The new bis(pentafluorophenyl)-palladium deriva-
tives 1–7 with iminophosphines are air-stable, white
solids. The IR spectra of these compounds show the
characteristic absorptions of the C6F5 group [37] at ca.
1630 m, 1490 vs, 1050 s and 950 vs cm−1. The presence
of two bands in the 800–780 cm−1 region for the so
called ‘X-sensitive’ mode of the C6F5 ligand is charac-
teristic of the cis-M(C6F5)2 fragment [38], which obvi-
ously appears in compounds containing bidentate
chelate ligands. The most relevant IR bands attributed
to the ligands in all the iminophosphine complexes
appear in the 1650–1600 cm−1 region. Thus, the IR
spectra of the complexes show a single strong band in
this region assigned to the CꢀN stretching vibration,
shifted to lower frequencies than in the free ligands.
The 1H NMR spectra show the corresponding
aliphatic and aromatic signals, with a typical iminic
singlet or doublet resonance in the 8–8.5 ppm region
depending on the strength of the coupling to the phos-
phorus atom [11]. The 31P NMR spectra of the
iminophosphine compounds consist of singlets with
chemical shifts in the range observed for Pd(II) com-
plexes and the 19F NMR spectra show the expected
pattern of three duplicated resonance signals, consistent
with the presence of two nonequivalent C6F5 groups,
one trans to N and one trans to P. Thus, there are two
different ortho-F resonances: a lower field doublet at-
tributed to the C6F5 ring trans to N and a higher field
multiplet caused by additional coupling with the trans P
atom. The 19F NMR spectrum of complex 5 at room
temperature, as observed previously for the nickel ana-
logues [31], shows broad resonances in the ortho- and
meta-F regions, suggesting that the bulky t-butyl group
slows down the ‘free’ rotation of the C6F5 rings. The
spectrum recorded at −20°C revealed that, at this
temperature, the rotation is sufficiently sluggish to
make the ortho-F atoms distinguishable by their differ-
ent chemical shifts, and three 2:1:1 doublet resonances
are observed. A similar behaviour was found for the
meta- and para-F resonances, resolved as four signals
with relative intensities of 1:2:2:1 at −20°C.
3.1. bis(Pentafluorophenyl) complexes
In acetone, cis-[Pd(C6F5)2(PhCN)2] reacts with
iminophosphines (molar ratio 1:1) under mild condi-
Table 1
Crystal data and structure refinement for [Pd(C6F5)(S C6H5)(iPrNP)]
Empirical formula
Formula weight
Temperature (K)
C34H27F5NPPdS
714.00
293(2) K
,
,
Wavelength (A)
0.7107 A
Crystal system
Space group
monoclinic
P21/c
Unit cell dimensions
,
a (A)
15.961(3)
12.594(3)
16.171(4)
90
103.45(2)
90
3161.4(12)
4
1.500
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
V (A )
Z
Dcalc (Mg m−3
)
Absorption coefficient (mm−1
Crystal size (mm)
)
0.757
0.40×0.40×0.20
2.07 to 21.97
4026
3866 [Rint=0.0348]
2761
q Range for data collection (°)
Reflections collected
Independent reflections
Number of reflections with
I\2s(I)
Max/min transmission
Refinement method
1.00, 0.89
Full-matrix least-squares on
F2
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
R indices (all data)
3866/0/388
1.016
R1 a=0.0432, wR2 b=0.0824
R1=0.0752, wR2=0.0942
a R1=ꢀꢀFoꢀ−ꢀFcꢀꢀ/ꢀFoꢀ.
b wR2=[[w(Fo2−Fc2)2]/[w(F2o)2]]0.5
.
3.2. Mono(pentafluorophenyl) complexes
The addition of the corresponding iminophosphine
to
a
solution of the chloro-bridged precursor
[{Pd(C6F5)(tht)}2(m-Cl)2] (molar ratio 1:2), in
dichloromethane, leads to the formation of the
organometallic complexes presented in Scheme 2. The
chloride derivatives 8–10 are white solids the IR spec-
tra of which show the characteristic absorptions of the
pentafluorophenyl group [38], together with a medium
band assigned to the Pd–Cl (at 296 cm−1) vibration
Scheme 1.

576
G. Sa´nchez et al. / Polyhedron 20 (2001) 571–578
tion of the neutral ligands and the obtention of the new
mixed-ligand complexes.
The IR spectra of the neutral (11–18) and cationic
(19–21) monopentafluorophenyl complexes show as
most remarkable feature the expected disappearance of
the Pd–Cl stretching absorption and the new bands
corresponding to the incoming ligands, collected in
Section 2. The presence of iminophosphine ligands in
the new complexes is also confirmed by 1H NMR
spectroscopy, as the three signals in 19F-spectra with
relative intensity of 2:1:2 revealed the presence of a
C6F5 ring bound to palladium. Again a hindered rota-
tion situation is observed for complex 19, and three
broad resonances appear in the 19F NMR spectrum at
room temperature. The spectrum recorded at −40°C
shows the expected pattern of two doublet signals
corresponding to two nonequivalent ortho-F atom, a
triplet for para-F and two still broad resonances for
meta-F.
Scheme 2.
A single resonance at approximately 31 ppm was
observed in the 31P{1H} NMR spectra of compounds
(8–10), where a weak Fo–P coupling (ca. 11 Hz) was
detected. This small value suggests a cis-geometry of
the C6F5 ring and the P atom around the palladium
centre, as does the fact that phosphorus resonance is
variably shifted in compounds (11–18) depending on
the different anionic ligand placed trans- to the
iminophosphinic–P. This extent is confirmed from the
X-ray crystal structure determination of complex 15
and in accordance with previously reported data for
related compounds [39]. The relative geometrical dispo-
sition of N–P ligand and C6F5 ring coordinating palla-
dium is also kept in the cationic complexes (19–21), as
revealed in their 31P MNR data. Thus, two doublet
signals characteristic of an AX system are observed,
with coupling constant values up to 400 Hz indicating a
trans-situation of P-atoms of iminophosphine and ter-
tiary phosphine, as shown in Scheme 4.
Scheme 3.
3.3. X-ray structure of
[Pd(C6F5)(SC6H5)(o-Ph2PC6H4–CHꢀNiPr)] (15)
and a strong absorption around 1630 cm−1 corre-
sponding to the iminophosphine ligands.
Selected bond distances and angles of 15 are pre-
sented in Table 2. The coordination around palla-
dium is approximately square planar. The main distor-
tion is the NPdP bite angle of 86.1(2)° similar to other
palladium complexes with iminophosphines [30]. The
Pd–S distance is similar to that found in others thiolate
complexes trans to a phosphorus atom [40]. The palla-
dium-bound C6F5 group is nearly orthogonal to the
palladium square plane; the angle between the plane
defined by PdPNS and the plane of the Pd-bound C6F5
group is 87.3(2)°. The chelate six-membered ring of the
iminophosphine is not coplanar with the N–Pd–P co-
ordination plane: the imino carbon C19 and the ortho
The chloro–pentafluorophenyl palladium(II) com-
plexes have shown to be convenient precursors for the
synthesis of new monopentafluorophenyl derivatives by
means of chloride metathesis reactions with other
monodentate
anionic
ligands.
Thus,
when
[Pd(C6F5)Cl(o-Ph2PC6H4–CHꢀNiPr)] (9) was made re-
act with several alkaline salts in acetone, the corre-
sponding products (11–18) of chloride metathesis were
obtained (Scheme 3). The synthesis of the new cationic
derivatives (19–21) is also achieved when complex 9
reacts in acetone with silver trifluoromethane sulfonate,
in the presence of neutral ligands (tertiary phosphines).
The precipitation of silver chloride allows the coordina-

G. Sa´nchez et al. / Polyhedron 20 (2001) 571–578
577
Scheme 4.
Table 2
General de Ensen˜anza Superior e Investigacio´n Cien-
t´ıfica (project PB97-1036) Spain, is acknowledged. J.P.
thanks CAJAMURCIA for a research grant.
,
Selected bond lenghts (A) and bond angles (°) for complex 15
Bond lengths
Pd–C(23)
Pd–P
2.002(6)
2.245(2)
Pd–N
Pd–S
2.103(5)
2.357(2)
Bond angles
C(23)–Pd–N
N–Pd–P
N–Pd–S
C(23)–Pd–P
177.5(2)
86.1(2)
90.8(2)
92.2(2)
C(23)–Pd–S
P–Pd–S
C(29)–S–Pd
91.0(2)
175.8(1)
110.8(2)
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