Homoleptic palladium complexes with phosphine-amide or iminophosphine ligands

Article abstract of DOI:10.1016/j.ica.2009.07.003

The reaction between Pd(dba)₂ and phosphino-amide ligands yielded the unexpected Pd(II) homoleptic complexes [Pd(o-Ph₂PC₆H₄CO-NR)₂] [R = ⁱPr (1), Ph (2), 4-MeC₆H₄ (3), 4-FC₆H₄ (4)], in which an κ²-P,N coordination mode for diphenylphosphine-benzamidate ligands is observed. In order to induce amide protonation in the ligands and subsequent κ²-P,O coordination, compounds (1-4) were treated with HClO₄(aq) to give cationic complexes [Pd(o-Ph₂PC₆H₄CO-NHR)₂][ClO ₄]₂ (5-8). These complexes and the analogous with iminophosphine ligands [Pd(o-Ph₂PC₆H₄CH{double bond, long}N-R)₂] [ClO₄]₂ [R = ⁱPr (9), Ph (10)] can be alternatively obtained when [PdCl₂(PhCN)₂] is treated with AgClO₄ in the presence of the corresponding ligand. The reaction of Pd(dba)₂ with iminophosphines has also been explored, yielding in this case the Pd(0) derivatives [Pd(o-Ph₂PC₆H₄CH{double bond, long}N-R)₂] [R = ⁱPr (11), Ph (12)]. X-ray structures of (3), (4), (5), (8) and (9) have been established, allowing an interesting comparative structural discussion.

Full text of DOI:10.1016/j.ica.2009.07.003

Inorganica Chimica Acta 363 (2010) 1084–1091
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Homoleptic palladium complexes with phosphine-amide or iminophosphine ligands
a
b
b
b
a
Gregorio Sánchez a, , Joaquín García , José L. Serrano , Luis García , José Pérez , Gregorio López
*
a Departamento de Química Inorgánica, Universidad de Murcia, 30071 Murcia, Spain
b Departamento de Ingeniería Minera, Geológica y Cartográfica, Área de Química Inorgánica, 30203 Cartagena, Spain
a r t i c l e i n f o
a b s t r a c t
Article history:
The reaction between Pd(dba)2 and phosphino-amide ligands yielded the unexpected Pd(II) homoleptic
complexes [Pd(o-Ph2PC6H4CO-NR)2] [R = iPr (1), Ph (2), 4-MeC6H4 (3), 4-FC6H4 (4)], in which an 2-P,N
coordination mode for diphenylphosphine–benzamidate ligands is observed. In order to induce amide
protonation in the ligands and subsequent
2-P,O coordination, compounds (1-4) were treated with
Received 15 April 2009
Received in revised form 26 June 2009
Accepted 5 July 2009
j
j
Available online 9 July 2009
HClO4(aq) to give cationic complexes [Pd(o-Ph2PC6H4CO-NHR)2][ClO4]2 (5-8). These complexes and the
analogous with iminophosphine ligands [Pd(o-Ph2PC6H4CH@N-R)2] [ClO4]2 [R = iPr (9), Ph (10)] can be
alternatively obtained when [PdCl2(PhCN)2] is treated with AgClO4 in the presence of the corresponding
ligand. The reaction of Pd(dba)2 with iminophosphines has also been explored, yielding in this case the
Pd(0) derivatives [Pd(o-Ph2PC6H4CH@N-R)2] [R = iPr (11), Ph (12)]. X-ray structures of (3), (4), (5), (8)
and (9) have been established, allowing an interesting comparative structural discussion.
Ó 2009 Elsevier B.V. All rights reserved.
Dedicated to Prof. Jonathan R. Dilworth
Keywords:
Phosphino-amides
Iminophosphines
Hemilabile ligands
Coordination modes
Crystal structures
Palladium
1. Introduction
in the catalytic behaviour [17]. In this sense, we have recently
studied the coordination properties of these mixed-donor biden-
Hybrid ligands that contain distinct chemical functions [1–5],
such as soft phosphine and hard (e.g. N or O) donor atoms, have at-
tracted continuous interest during last years as a result of their
versatile coordination behaviour [6,7] and its potential hemilabili-
ty [3–5]. These properties have been exploited in several ways, as
the ‘‘weak-link approach” for the synthesis of supramolecular
structures [8] or the use of some ligands and its complexes in
chemical sensing [9–11] and catalytic processes. It is in this last
field that phosphine-amide ligands have received growing atten-
tion. For example, the asymmetric 1,4-addition reaction of arylbo-
ronic acids with cycloalkenones is catalysed by an amidophosphine
rhodium(I) complex [12], and also amide derived phosphines
(Aphos) possessing various N,N-dialkyl aromatic amide scaffolds
have shown to be highly effective in Suzuki cross-coupling reac-
tions [13,14]. The last generation of such Aphos ligands has been
able to promote room-temperature coupling of unactivated and
sterically hindered aryl chlorides [15] and a recent review explored
the use of catalysts containing hemilabile ligands in the Suzuki
reaction [16]. Also 2-diphenylphosphinobenzamido nickel com-
plexes have found application in ethylene polymerization, showing
that slight variations in the ligand frame produce drastic changes
tate ligands in their first described ruthenium(II) [18] and palla-
dium(II) complexes containing cyclometallated [19] or
pentafluorophenyl co-ligands [20].
On the other hand, metal complexes containing iminophos-
phine ligands prepared by condensation of 2-(diphenylphos-
phino)benzaldehyde with primary amines (o-Ph2PC6H4CH@N-R)
were first reported in the early nineties by Dilworth an other
authors [21–23]. Since then palladium iminophosphine com-
plexes have also been known to act as versatile catalysts for
many different reactions, such as the copolymerization of carbon
monoxide and ethylene [24], the hydrosilylation of ketones [25]
and Heck [26,27], Suzuki [25,28–30] and Stille couplings [31–
34]. In this last reaction in situ mixtures of Pd(dba)2 with the
above mentioned iminophosphines (o-Ph2PC6H4CH@N-R) have
shown outstanding efficiency [34]. We present in this paper as
an extension of previous work the synthesis and characterization
of homoleptic-iminophosphine Pd(0) complexes that, as men-
tioned above, have not been isolated before although its catalytic
activity have been demonstrated when used in situ. The new
analogous cationic compounds of Pd(II) prepared as perchlorate
salts are reported too. The study of the coordination behaviour
of diphenylphosphine-benzamide ligands o-Ph2PC6H4CO–NHR,
containing steric and electronically differentiated substituents,
in its reactions against Pd(dba)2 and [PdCl2(PhCN)2] is also
described.
* Corresponding author.
E-mail address: gsg@um.es (G. Sánchez).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.07.003

G. Sánchez et al. / Inorganica Chimica Acta 363 (2010) 1084–1091
1085
2.2.2. Preparation of complexes [Pd(o-Ph2PC6H4CO–NHR)2][ClO4]2
2. Experimental
[R = iPr (5), Ph (6), 4-MeC6H4 (7), 4-FC6H4 (8)]
2.2.2.1. Method A. The new complexes were obtained by treating a
dichloromethane solution of the corresponding complexes (1–4)
(100 mg, 20 mL) with stoichiometric amount of 1.16 M HClO4
aqueous solution (molar ratio: 1:2). After 1 h stirring at room tem-
perature, the mixture was concentrated to half volume under re-
duced pressure. Addition of diethyl ether caused precipitation of
the new yellow complexes (5–8), which were filtered off, washed
with ether, air dried and recrystallized from CH2Cl2/ether.
2.1. Methods and materials
C, H and N analyses were carried out with a Carlo Erba instru-
ment. IR spectra were recorded on a Perkin–Elmer spectrophotom-
eter 16F PC FT–IR, using Nujol mulls between polyethylene sheets.
NMR data (1H, 31P) were recorded on Bruker Avance 200 and 300
spectrometers. Mass spectrometric analyses were performed on a
Fisons VG Autospec double-focusing spectrometer, operated in po-
sitive mode. Ions were produced by fast atom bombardment (FAB)
with a beam of 25 KeV Cs atoms. The mass spectrometer was oper-
ated with an accelerating voltage of 8 kV and a resolution of at
least 1000. All the solvents were dried by conventional methods.
Pd(dba)2 [35], the diphenylphosphinobenzamide o-Ph2P–C6H4–
CO–NH–R (R = iPr, Ph, 4-MeC6H4 or 4-FC6H4 and iminophosphine
ligands o-Ph2PC6H4CH@N-R (R = iPr or Ph) were prepared by re-
ported procedures [20,21].
2.2.2.2. Method B. To
a solution of [PdCl2(PhCN)2] (100 mg,
0,26 mmol) in 10 mL of dichloromethane, the stoichiometric
amount of the corresponding 2-diphenylphosphinebenzamide
(0.52 mmol, molar ratio 1:2) and AgClO4 (108 mg, 0.52 mmol)
were added. The precipitation of AgCl started immediately. After
30 min of stirring at room temperature the precipitate was re-
moved, and the resulting clear solution was evaporated to half vol-
ume. A yellow precipitate formed after addition of diethyl ether
and then it was filtered off and washed with ether. The complexes
(5–8) were recrystallised from CH2Cl2/ether.
2.2. Synthesis
[Pd(o-Ph2PC6H4CO–NH–iPr)2][ClO4]2 (5): (73% yield).. Mp =
235 °C. Anal. Calc. for C44H44Cl2N2O10P2Pd: C, 52.8; H, 4.4; N, 2.8.
2.2.1. Preparation of complexes [Pd(o-Ph2PC6H4CO–NR)2] [R = iPr (1),
Ph (2), 4-MeC6H4 (3), 4-FC6H4 (4)]
Found: C, 53.1; H, 4.6; N, 2.7.%. FT–IR (nujol, cmꢀ1):
m
(NH) 3287,
(ClO4) 1093 (vs). 1H NMR (300 MHz, CDCl3): d
To a red solution of [Pd(dba)2] (200 mg, 0,35 mmol) in 20 mL of
dicholoromethane was added the stoichiometric amount of the
corresponding 2-diphenylphosphinebenzamide (0.70 mmol, molar
ratio 1:2). The reaction was stirred at room temperature for 24 h
and then it was evaporated to half volume under reduced pressure.
Addition of diethyl ether caused precipitation of the new yellow
complexes, which were filtered off, air dried and recrystallised
from CH2Cl2/ether. The same results were obtained when the reac-
tions were performed under air or N2 atmosphere.
m(CO) 1584 (vs), m
(ppm): 8.89 (m, 2H, NH), 8.30 (m, 2H, P–C6H4–C), 7.92 (m. 2H, P–
C6H4–C), 7.65–7.51 (m, 10H, 2H P–C6H4–C + 8H PPh2), 7.40–7.28
(m, 12H, PPh2), 6.90 (m, 2H, P–C6H4–C), 3.95 (m, 2H, CH-iPr),
0.94 (d, JHH = 6.0 Hz, 12H, CH3-iPr). 31P NMR (300 MHz, CDCl3): d
(ppm) 44.5(s). FAB-MS (positive mode) m/z: 898 (M+-ClO4), 797
(M+-2ClO4).
[Pd(o-Ph2PC6H4CO–NH–Ph)2][ClO4]2
Mp = 194 °C. Anal. Calc. for C50H40Cl2N2O10P2Pd: C, 56.2; H, 3.8;
N, 2.6. Found: C, 56.1; H, 4.0; N, 2.8.%. FT–IR (nujol, cmꢀ1):
(CO)
1578 (vs),
(ClO4) 1097 (vs). 1H NMR (200 MHz, CDCl3): d (ppm):
(6):
(68%
yield).
[Pd(o-Ph2PC6H4CO–N–iPr)2] (1): (72% yield). Mp = 155 °C. Anal.
Calc. for C44H42N2O2P2Pd: C, 66.1; H, 5.3; N, 3.5. Found: C, 65.8;
m
m
H, 5.7; N, 3.6.%. FT–IR (nujol, cmꢀ1): (CO) 1623 (s), 1574 (vs). 1H
m
10.49 (br, 2H, NH), 8.41 (m, 2H, P–C6H4–C), 7.83 (m, 2H, P–C6H4–
C), 7.69–7.16 (m, 32H, 20H PPh2 + 10H N-Ph + 2H P–C6H4–CO–),
6.95 (m, 2H, P–C6H4–C). 31P NMR (300 MHz, CDCl3): d (ppm) 43.2
(s). FAB-MS (positive mode) m/z: 867 (M+-2ClO4 + 1).
NMR (200 MHz, CDCl3): d (ppm): 8.26 (m, 2H, P-C6H4-CO–),
7.88–7.24 (m, 24H, 20H PPh2 + 4H P–C6H4–CO–), 6.43 (m, 2H, P-
C6H4-CO–), 3.70 (m, 2H, CH-iPr), 1.05 (d, JHH = 6.0 Hz, 6H, CH3-iPr),
0.65 (d, JHH = 6.0 Hz, 6H, CH3-iPr). 31P NMR (300 MHz, CDCl3): d
(ppm): 32.5 (s). FAB-MS (positive mode) m/z: 799 (M++1).
[Pd(o-Ph2PC6H4CO–NH–C6H4–4Me)2][ClO4]2 (7) (69% yield).
Mp = 231 °C. Anal. Calc. for C52H44Cl2N2O10P2Pd: C, 57.0; H, 4.1;
N, 2.6. Found: C, 57.2; H, 4.3; N, 2.9.%. FT–IR (nujol, cmꢀ1):
3371 (s), m(CO) 1577 (vs), m
m
(NH)
[Pd(o-Ph2PC6H4CO–N–Ph)2] (2) (80% yield). Mp = 177 °C. Anal.
Calc. for C50H38N2O2P2Pd: C, 69.3; H, 4.4; N, 3.2. Found: C, 69.4;
(ClO4) 1103 (vs). 1H NMR (300 MHz,
H, 4.7; N, 3.3.%. FT–IR (nujol, cmꢀ1): (CO) 1655 (s), 1580 (vs). 1H
m
CDCl3): d (ppm): 10.51 (s, 2H, NH), 8.46 (m, 2H, P–C6H4–C), 7.88
(m, 2H, P–C6H4–C), 7.55–7.48 (m, 6H, 2H P–C6H4–C + 4H N–
C6H4–CH3), 7.36–7.28 (m, 20 H PPh2) 7.05 (m, 4H, N–C6H4–Me),
6.94 (m, 2H, P–C6H4–C), 2.27 (s, 6H, CH3). 31P NMR (300 MHz,
CDCl3): d (ppm) 43.3 (s). FAB-MS (positive mode) m/z: 995 (M+-
ClO4), 894 (M+-2ClO4).
NMR (200 MHz, CDCl3): d (ppm): 8.11 (m, 2H, P–C6H4–CO–),
7.92–7.31 (m, 32H, 20H PPh2 + 10H N-Ph + 2H P–C6H4–CO–),
6.58 (m, 2H, P–C6H4–CO–). 31P NMR (300 MHz, CDCl3): d (ppm)
33.3 (s). FAB-MS (positive mode) m/z: 867 (M+ + 1).
[Pd(o-Ph2PC6H4CO–N–C6H4–4Me)2]
Mp = 196 °C. Anal. Calc. for C52H42N2O2P2Pd: C, 69.8; H, 4.7; N,
3.1 Found: C, 69.5; H, 5.1; N, 3.3.%. FT–IR (nujol, cmꢀ1):
(CO)
(3)
(74%
yield).
[Pd(o-Ph2PC6H4CO–NH–C6H4–4F)2][ClO4]2 (8) (75% yield).
m
Mp = 191 °C. Anal. Calc. for C50H38Cl2F2N2O10P2Pd: C, 54.4; H, 3.5;
1612 (s), 1593 (vs). 1H NMR (300 MHz, CDCl3): d (ppm) 7.97 (m,
2H, P–C6H4–CO–), 7.52–7.35 (m, 12H, 8H PPh2 + 4H N–C6H4–
CH3), 7.22 (m, 2H, P–C6H4–CO–), 7.09 (m, 2H, P–C6H4–CO–), 6.86
(m, 12H, PPh2), 6.68 (m, 4H, N–C6H4–CH3), 6.57 (m, 2H, P–C6H4–
CO–), 2.16 (s, 6H, CH3). 31P NMR (300 MHz, CDCl3): d (ppm) 33.2
(s). FAB-MS (positive mode) m/z: 894 (M+).
N, 2.5. Found: C, 54.7; H, 3.9; N, 2.8.%. FT–IR (nujol, cmꢀ1):
3336 (s), m(CO) 1580 (vs), m
m
(NH)
(ClO4) 1100 (vs). 1H NMR (200 MHz,
CDCl3): d (ppm): 11.05 (br, 2H, NH), 8.46 (m, 2H, P–C6H4–C), 7.85
(m, 2H, P–C6H4–C), 7.75 (m, 2H, P–C6H4–C), 7.69–7.62 (m, 16H,
12H PPh2 + 4H N–C6H4–F), 7.40–7.30 (m, 10H, 8H aromatics +2H
P–C6H4–C), 6.99 (m, 4H N–C6H4–F). 31P NMR (300 MHz, CDCl3): d
(ppm) 41.4 (s). 19F NMR (200 MHz, CDCl3): d (ppm): ꢀ120.3(s).
FAB-MS (positive mode) m/z: 903 (M+-2ClO4).
[Pd(o-Ph2PC6H4CO–N–C6H4–4F)2] (4) (68% yield). Mp = 206 °C.
Anal. Calc. for C50H36F2N2O2P2Pd: C, 66.5; H, 4.0; N, 3.1. Found: C,
66.4; H, 4.4; N, 3.4.%. FT–IR (nujol, cmꢀ1):
m(CO) 1604(s), 1576
(vs). 1H NMR (200 MHz, CDCl3): d (ppm) 8.02 (m, 2H, P–C6H4–
CO–), 7.52–7.35 (m, 12H, 8H PPh2 + 4H N–C6H4–F), 7.22 (m, 2H,
P–C6H4–CO–), 7.19 (m, 2H, P–C6H4–CO–), 6.90 (m, 12H, PPh2),
6.58 (m, 6H, 4H N–C6H4–F + 2H P–C6H4–CO–). 31P NMR
(300 MHz, CDCl3): d (ppm) 33.5 (s). 19F NMR (200 MHz, CDCl3): d
(ppm): ꢀ120.3 (s). FAB-MS (positive mode) m/z: 902 (M+).
2.2.3. Preparation of complexes [Pd(o-Ph2PC6H4CH@N-R)2] [ClO4]2
[R = iPr (9), Ph (10)]
To a solution of [PdCl2(PhCN)2] (100 mg, 0,26 mmol) in 10 mL of
dichloromethane, the stoichiometric amount of the corresponding
iminophosphine (0.52 mmol, CH2Cl2 solution) and AgClO4 (108 mg,
0.52 mmol) were added. The precipitation of AgCl started immedi-

1086
G. Sánchez et al. / Inorganica Chimica Acta 363 (2010) 1084–1091
ately. After 30 min of stirring at room temperature the precipitate
was removed, and the resulting clear solution was evaporated to
half volume. An orange precipitate formed after addition of diethyl
ether and then it was filtered off and washed with ether. The com-
plexes (9 and 10) were recrystallised from CH2Cl2/ether.
[Pd(o-Ph2PC6H4CH@N-iPr)2] (11): (62% yield). Mp = 95 °C. Anal.
Calc. for C44H44N2P2Pd: C, 68.7; H, 5.7; N, 3.6. Found: C, 69.0; H,
5.9; N, 3.8.%. FT–IR (nujol, cmꢀ1):
m
(C@N) 1650(s), 1591(s). 1H
NMR (300 MHz, CDCl3): d (ppm): 8,63 (br, 2H, CH@N), 8.12–
6.12(m, 28H, arom.) 3.28 (m, 2H, CH-iPr) 1,19 (d, JHH = 6.9 Hz,
12H, CH3-iPr). 31P NMR (300 MHz, CDCl3): d (ppm) 29.1(s). FAB-
MS (positive mode) m/z: 683 (M+-2iPr).
[Pd(o-Ph2PC6H4CH@N-iPr)2][ClO4]2 (9): (64% yield). Mp = 190
°C. Anal. Calc. for C44H44Cl2N2O8P2Pd: C, 54.6; H, 4.5; N, 2.9. Found:
C, 54.8; H, 4.7; N, 3.0.%. FT–IR (nujol, cmꢀ1):
m
m
(C@N) 1646 (s),
[Pd(o-Ph2PC6H4CH@N-Ph)2] (12): (85% yield). Mp = 117 °C. Anal.
Calc. for C50H40N2P2Pd: C, 71.8; H, 4.8; N, 3.3. Found: C, 72.0; H,
(ClO4) 1090 (vs). 1H NMR (300 MHz, CDCl3): d (ppm): 8.00 (s,
2H, HC@N), 7.91 (m, 2H, P–C6H4–C), 7.80–6.23 (m. 24H, 4 P–
C6H4–C + 20H PPh2), 6.86 (m, 2H, P–C6H4–C), 3.55 (m, 2H, CH-iPr),
0.94 (d, JHH = 6.6 Hz, 12H, CH3-iPr). 31P NMR (300 MHz, CDCl3): d
(ppm) 32.5(s). FAB-MS (positive mode) m/z: 869 (M+-ClO4).
5.0; N, 3.3.%. FT–IR (nujol, cmꢀ1): (C@N) 1650(s), 1590(s). 1H
m
NMR (200 MHz, CDCl3): d (ppm): 8.53 (s, 2H, HC@N), 7.90–6.95
(m. 36H, 6H P–C6H4–C + 20H PPh2 + 10H N–Ph), 6.90 (m, 2H, P–
C6H4–C),. 31P NMR (300 MHz, CDCl3): d (ppm) 31.2 (s). FAB-MS (po-
sitive mode) m/z: 836 (M+).
[Pd(o-Ph2PC6H4CH@N-Ph)2][ClO4]2
Mp = 193 °C. Anal. Calc. for C50H40Cl2N2O8P2Pd: C, 58.0; H, 3.9; N,
2.7. Found: C, 58.2; H, 4.1; N, 3.0.%. FT–IR (nujol, cmꢀ1):
(C@N)
1622 (s),
(ClO4) 1097 (vs). 1H NMR (200 MHz, CDCl3): d (ppm):
(10):
(61%
yield).
m
2.3. Crystal structure determination of (3), (4), (5), (8) and (9)
m
8.20 (s, 2H, HC@N), 7.65 (m, 2H, P–C6H4–C), 7.41 (m, 2H, P–
C6H4–C), 7.21–6.95 (m. 32H, 2H P–C6H4–C + 20H PPh2 + 10H N–
Ph), 6.81 (m, 2H, P–C6H4–C), 31P NMR (300 MHz, CDCl3): d (ppm)
35.2 (s). FAB-MS (positive mode) m/z: 937 (M+-ClO4).
Crystals of (3) (0.14 ꢁ 0.06 ꢁ 0.06 mm3), (4) (0.09 ꢁ 0.06 ꢁ
0.04 mm3), (5) (0.11 ꢁ 0.10 ꢁ 0.08 mm3), (8) (0.15 ꢁ 0.08 ꢁ
0.06 mm3) and (9) (0.25 ꢁ 0.11 ꢁ 0.10 mm3) suitable for a diffrac-
tion study were prepared by slow diffusion of hexane into their
dichloromethane solutions, mounted on glass fibre and transferred
to a Bruker Smart CCD diffractometer at ꢀ173 °C. The crystallo-
2.2.4. Preparation of complexes [Pd(o-Ph2PC6H4CH@N-R)2] [R = iPr
(11), Ph (12)]
graphic data are summarised in Table 1. Mo Ka radiation was used
To a red solution of [Pd(dba)2] (200 mg, 0,35 mmol) in 20 mL of
dichloromethane was added the stoichiometric amount of the cor-
responding iminophosphine previously prepared (0.70 mmol,
CH2Cl2 solution). The reaction was stirred at room temperature
for 1 h and then it was evaporated to half volume under reduced
pressure. Addition of diethyl ether caused precipitation of the
new yellow/orange complexes, which were filtered off, air dried
and recrystallised from CH2Cl2/ether. The same results were ob-
tained when the reactions were performed under air or N2
atmosphere.
(k = 0.71073 Å). The structures were solved by direct methods
(excepting (8) that was done by Patterson methods) and refined
anisotropically on F2 [36].
The ranges of hkl were ꢀ13 6 h 6 13, ꢀ15 6 k 6 15,
ꢀ25 6 l 6 25 for (3), ꢀ22 6 h 6 23, ꢀ15 6 k 6 15, ꢀ24 6 l 6 24
for (4), ꢀ13 6 h 6 13, ꢀ23 6 k 6 22, ꢀ32 6 l 6 32 for (5),
ꢀ15 6 h 6 16, ꢀ26 6 k 6 25, ꢀ24 6 l 6 25 for (8) and 22 6 h 6 23,
ꢀ22 6 k 6 21, ꢀ25 6 l 6 24 for (9), respectively. Hydrogen atoms
were introduced in calculated positions, except in complexes (3)
and (8) where hydrogen atoms positions belonging to water mole-
Table 1
Crystal data and structure refinement for compounds (3), (4), (5), (8) and (9).
3
4
5
8
9
Empirical formula
Formula weight
C52H42N2O2P2Pd.2H2O
C50H36F2N2O2P2Pd
903.15
100(2)
C44H44Cl2N2O10P2Pd
1000.05
100(2)
C50H38Cl2F2N2O10P2Pd.H2O C44H44Cl2N2O8P2Pd.CH2Cl2
931.25
100(2)
0.546
1122.08
100(2)
0.647
1052.98
100(2)
0.770
Temperature (K)
Absorption coefficient
0.607
0.667
(mmꢀ1
)
Crystal system
Space group
a (Å)
b (Å)
c (Å)
triclinic
P1
monoclinic
C2/c
17.8316(16)
12.3863(11)
18.4784(6)
90
104.784(2)
90
3946.2(6)
4
orthorhombic
Pbnn
10.2127(4)
17.8225(8)
24.5073(11)
90
90
90
4460.7(3)
4
1.489
monoclinic
P21/n
12.4876(5)
19.6641(7)
19.2333(7)
90
91.152(1)
90
4717.1(3)
4
monoclinic
P21/n
13.8266(11)
16.8343(14)
19.4930(16)
90
90.286(1)
90
4537.2(6)
4
ꢀ
10.7736(5)
11.4828(5)
19.3207(9)
77.7550(10)
75.2820(10)
73.3040(10)
2189.20 (17)
2
a
(°)
b (°)
c
(°)
V (Å3)
Z
Dcalc (Mg mꢀ3
F(0 0 0)
)
1.413
960
1.520
1840
1.580
2280
1.542
2152
2048
Reflections collected
25543
22567
48947
54276
51122
Independent reflections
9487 (0.0433)
4593 (0.0599)
5328 (0.0591)
11001 (0.0588)
10479 (0.0518)
(Rint
)
Parameters
566
267
270
639
569
Refinement method
full-matrix least-squares
full-matrix least-squares
full-matrix least-squares
full-matrix least-squares
full-matrix least-squares
on F2
on F2
on F2
on F2
on F2
a
R1
0.0469
0.0960
1.057
0.0453
0.1065
1.079
0.0746
0. 1923
0.905
0.0620
0.1313
1.099
0.1080
0.2513
1.068
b
wR2
Sc
Maximum, minimum
D
q
0.618, ꢀ0.708
0.664, ꢀ0.6415
2.536, ꢀ2.514
1.762, ꢀ1.386
2.529, ꢀ1.966
(e Åꢀ3
)
P
P
a
b
c
R1
=
||F0 |–|FC||/ |F0| for reflections with I > 2
r
I.
2
2
1=2
wR2 ¼ f
R
½wðF20 ꢀ F2c Þ ꢂ=
R
½wðF20Þ ꢂg
for all reflections; wꢀ1 2(F2) + (aP)2 + b P, were P = (2 Fc2 + F02)/3 and a and b are constants set by the program.
= r
2
S ¼ f
R
½wðF02 ꢀ Fc2Þ ꢂ=ðn ꢀ pÞg1=2; n is the number of reflections and p the total number of parameters refined.

G. Sánchez et al. / Inorganica Chimica Acta 363 (2010) 1084–1091
1087
cules were refined. Data are of poor quality, assessed by a mean va-
Ph (2), 4-MeC6H4 (3), 4-FC6H4 (4)] in which an
j
2-P,N coordination
lue of I/sig(I) always lower than 10. For this reason in complex (8) a
ClO4 anion show high thermal parameters. Because Uij values on
mode for diphenylphosphine-benzamidate ligands is observed. The
spectroscopic and analytical data are in agreement with the pro-
ꢀ
neighbouring atoms tend to be similar DELU, SIMU and ISOR re-
straints [36] were applied. In complex (9) ISOR was applied to a
dichloromethane molecule. Data were corrected for absoption with
SADABS [37].
Complex (5) exhibits crystallographic C2 symmetry. In one per-
chlorate the chlorine atom lies on a C2 axis, so only two positions
were refined for oxygen atoms. In the second perchlorate chlorine
and one oxygen atom lie on a C2 axis (special positions). The
remaining oxygen atoms were found in general positions with a
50% occupation factor.
posed structures presented in Scheme 1. Thus, the loss of
m(NH)
bands in their IR spectra and the presence of (CO) absorptions
m
in the range observed for the free ligands (1604–1655 cmꢀ1) gives
a first support for the formation of a P–N chelate around the Pd
centre [19,20], confirmed by the FAB mass spectrometry that dis-
plays fragments corresponding to M+ or M+ + 1. The presence of
diphenylphosphine-benzamidate ligands is also observed by
31P{1H} NMR spectroscopy, the spectra consisting of singlets
around 33 ppm. This data is in agreement with those obtained in
the characterization of cyclopalladated compounds with anionic
diphenilphosphine-benzamidate ligands [19].
Thus, under our conditions the expected complexes of Pd(0) and
diphenylphosphinobenzamides are not stable and instead Pd(II)
complexes were obtained. The formation of related Pd(II) com-
plexes was mentioned by Trost et al. [38,39] in the reaction of
Pd2(dba)3 whit the chiral bidentate ligand (1S,2S)-(-)-1,2-diamino-
cyclohexane-N,N0-bi(2-diphenylphosphino-1-benzoyl) and re-
cently the mechanism of formation of such Pd(II) complexes with
a very similar Trost type ligands has been explored by Amatore
3. Results and discussion
3.1. Oxidative addition reactions of diphenylphosphine-benzamides to
Pd(0)
In dichloromethane, the precursor Pd(dba)2 reacts at room tem-
perature with o-Ph2P–C6H4–CO–NH–R yielding the yellow com-
pounds of general formula [Pd(o-Ph2PC6H4CO–NR)2] [R = iPr (1),
Ph
Ph
Ph
Ph
Pd(dba)2
CH2Cl2
P
P
+
24h
2 PPh2(o-C6H4CONHR)
Pd
N
N
i
(1)
(2)
(3)
(4)
R= Pr , Ph , CH3-C6H4 , F-C6H4
O
O
R
R
Scheme 1. Preparation of homoleptic derivatives (1–4) with
j
2-P,N coordination mode.
Ph
Ph
oxidative
addition
Ph
Ph
Pd(dba)2
+
P
P
2 PPh2(o-C6H4CONHR)
Pd
N
H
O
HN
R
O
R
intr amolecular
deprotonation
- H2
Ph
Ph
Ph
Ph
P
P
Pd
N
N
O
O
R
R
Scheme 2. Proposed routes for the formation of complexes (1–4).

1088
G. Sánchez et al. / Inorganica Chimica Acta 363 (2010) 1084–1091
Table 2
lengths and angles around Pd are similar in both complexes and
Selected bond lengths (Å) and angles (°).
also in the range of those found in the few related complexes de-
scribed previously [19,40]. Complex (3) is involved in four hydro-
gen bondings with two H2O molecules forming infinite chains as
shown in Fig. 3 (distance O(2)ꢃ ꢃ ꢃO(3) 2.782(3) Å and angle O(3)–
H(54)ꢃ ꢃ ꢃO(2) 170(4)°; distance O(2)ꢃ ꢃ ꢃO(3) 2.856(4) Å and angle
O(3)–H(53)ꢃ ꢃ ꢃO(2) 173(4)°; distance O(1)ꢃ ꢃ ꢃO(4) 2.840(3) Å and
angle O(4)–H(55)ꢃ ꢃ ꢃO(1) 166(4)°; distance O(1)ꢃ ꢃ ꢃO(4) 2.797(4) Å
and angle O(4)-H(56)ꢃ ꢃ ꢃO(1) 168.(5)°).
Bond length (Å)/ (3)
angle(°)
(4)
(5)
(8)
(9)
Pd(1)–N(1)
Pd(1)–N(2)
Pd(1)–P(1)
Pd(1)–P(2)
Pd(1)–O(1)
Pd(1)–O(2)
N(1)–Pd(1)–
N(2)
N(1)–Pd(1)–P(1) 81.19(7)
N(1)–Pd(1)–P(2) 167.17(7)
N(2)–Pd(1)–P(1) 165.91(6)
N(2)–Pd(1)–P(2) 82.71(7)
P(1)–Pd(1)–P(2)
N(1)–Pd(1)–
N(1)#1
N(1)#1–Pd(1)–
P(1)
2.091(2)
2.092(2)
2.094(2)
2.116(6)
2.104(7)
2.2594(8) 2.2454(7) 2.2268(11) 2.2292(10) 2.2572(19)
2.2584(8)
2.2145(10) 2.255(2)
2.066(3)
2.039(3)
2.051(3)
89.33(9)
89.7(2)
3.2. Synthesis and characterization of P,O-diphenylphosphine-
benzamide complexes of palladium(II)
83.86(7)
87.14(17)
165.23(18)
165.04(19)
87.28(19)
In order to induce amide protonation in the ligands, and a likely
2-P,O coordination mode according to our previous studies with
108.35(3)
103.88(4)
99.29(7)
j
90.38(13)
164.99(6)
nickel and palladium organometallic complexes, compounds (1–
4) were treated with HClO4(aq) in dichloromethane as described
in the experimental section, to yield yellow cationic complexes
[Pd(o-Ph2PC6H4CO–NHR)2][ClO4]2 [R = i-Pr (5), Ph (6), 4-MeC6H4
P(1)–Pd(1)–
P(1)#1
P(1)–Pd(1)–O(1)
P(1)–Pd(1)–
O(1)#1a
104.91(4) 101.90(6)
(7), 4-FC6H4 (8)]. The presence of both m(NH) and m(ClO4) bands
87.25(9)
167.65(9)
84.93(8)
168.72(8)
in their IR spectra accompanied by a noticeable change in the car-
bonyl region, in comparison with the corresponding precursors,
confirmed that the proposed reactions took place. Alternatively,
the complexes were prepared by reaction of the labile complex
[PdCl2(PhCN)2] with the 2-diphenylphosphine-benzamide (molar
ratio 1:2) ligands and AgClO4 in CH2Cl2. After elimination of the
precipitated AgCl, complexes (5–8) were isolated as perchlorate
salts. The positive FAB mass spectra of the complexes shows sig-
nals at m/z due to the [Pd(o-Ph2PC6H4CO–NHR)2]+ and [Pd(o-
Ph2PC6H4CO–NHR)2(ClO4)]+ fragments. A singlet shifted towards
low field compared to P,N-chelated neutral compounds character-
izes the 31P{1H} NMR spectra, and the expected pattern is observed
in the 1H NMR with significant presence of amidic proton reso-
nance at low field. Measurements of their molar conductivity in
acetone solutions indicate that all the complexes behave as 1:1
electrolytes [41], in accordance with the proposed formulae.
It was possible to grow X-ray quality crystals that after diffrac-
tion study have confirmed the structures of, (5) and (8). Each of
O(1)–Pd(1)–
85.00(18)
85.42(11)
O(1)#1a
P(2)–Pd(1)–O(1)
P(2)–Pd(1)–O(2)
167.72(8)
86.59(8)
a
O(2) in (8).
and Jutand [40]. According to their proposal, Pd(II) complexes
would be generated by either oxidation of Pd0(fosfine-amide)2 by
air or an alternative reaction involving intramolecular activation
of one N–H bond by the Pd(0) centre leading to a Pd(II) hydride.
In this case subsequent intramolecular deprotonation would give
the complexes 1–4 (Scheme 2). X-ray diffraction analysis has con-
firmed the structures of (3) and (4), providing a set of structural
data that enrich some aspects discussed above. Selected bond dis-
tances and angles are presented in Table 2 and their molecular
structures are shown in Figs. 1 and 2, respectively. The bond
them consisted of
a cationic complex [Pd(o-Ph2PC6H4CO–
Fig. 1. ORTEP diagram of complex (3) with the atom numbering scheme;
Fig. 2. ORTEP diagram of complex (4) with the atom numbering scheme;
displacement ellipsoids are drawn at the 50% propability level.
displacement ellipsoids are drawn at the 50% propability level.

G. Sánchez et al. / Inorganica Chimica Acta 363 (2010) 1084–1091
1089
Fig. 3. Molecules of (3) joining into infinite chains with O1 and O2 bridged by two H2O molecules.
NHR)2]2+ (Figs. 4 and 5, respectively) and two ClO4 anions, with
just one of them involved in hydrogen bonding with the amidic
ꢀ
ꢀ
nitrogens. Thus a ClO4 anion in complex (5) links by hydrogen
bond two units of complex in
a C2 symmetry (distance
N(1)ꢃ ꢃ ꢃO(2) 2.898(5) Å and angle N(1)–H(1)ꢃ ꢃ ꢃO(2) 164.0°) generat-
ing a linear chain (Fig. 6). In complex (8) there are also hydrogen
bonding characterized by the distance N(2)ꢃ ꢃ ꢃO(3) of 3.019(4) Å
and the angle N(2)–H(2)ꢃ ꢃ ꢃO(3) of 157.8°, and distance
O(11)ꢃ ꢃ ꢃO(10) of 2.812(14) Å and the angle O(11)–H(11B)ꢃ ꢃ ꢃO(10)
of 164.(11)°, respectively.
Selected bond lengths and angles listed in Table 2 are very sim-
ilar in both complexes.
The Pd(1)–O(1) distances are shorter than those reported for re-
lated compounds containing a carbonyl group involved in P,O che-
lation to a palladium centre [7,19].
3.3. Synthesis and characterization of homoleptic Pd(II) and Pd(0)
iminophosphine complexes
Following an analogous route as the one described above,
[PdCl2(PhCN)2] reacts in dichloromethane with iminophosphines
(molar ratio 1:2) and the stoichiometric amount of AgClO4 to yield
the homoleptic cationic complexes [Pd(o-Ph2PC6H4CH@N-
R)2][ClO4]2 [R = iPr (9), Ph (10)] (Scheme 3).
Fig. 4. ORTEP diagram of complex (5); displacement ellipsoids are drawn at the 50%
probability level.
The cationic palladium complexes are air-stable yellow solids
and their infrared spectra show a single strong band in the double
bond region attributed to the C@N stretching vibrations, shifted to
lower frequencies than in free ligands. The complexes also exhibit
ꢀ
the characteristic absorptions of the ClO4 anion at ca. 1100 and
600 cmꢀ1 and measurements of their molar conductivity in ace-
tone solutions indicate that they behave as 2:1 electrolytes [41],
in accordance with the proposed formulae. The 31P NMR spectra
of the compounds consist of singlets with chemical shifts in the
usual range of Pd(II) iminophosphine complexes [42–45]. The posi-
tive FAB-MS spectra of the complexes show the peaks for the M+-
Fig. 5. X-ray crystal structure of (8). Displacement ellipsoids are drawn at 50%
probability.
ꢀ
Fig. 6. View of the ClO4 – H-bonded chains in complex (8).

1090
G. Sánchez et al. / Inorganica Chimica Acta 363 (2010) 1084–1091
Ph
Ph Ph
Ph
CH=N-R
PPh2
P
P
Pd
[PdCl2(PhCN)2] + 2
HC
N
R
N
R
CH
R= iPr (9), Ph (10)
Scheme 3. Preparation of homoleptic Pd(II) iminophosphine complexes.
Table 3
Conformation and deformation (°) of six-membered rings for complexes (3), (4), (5),
(8) and (9).
(3)
Pd N C C C 1.00
(4)
(5)
(8)
(9)
1.00
SB
0.99 SB 1.00
SB
0.94
SB
0.97
SB
P
SB
11°
9°
0.01 TB 14°
0.06
HC
6°
0.03
HC
5°
13°
Pd P C C C
O
0.91
SB
0.65 E
0.09
B
0.26
HC
15°
0.09
SB
12°
measures of improper torsion angles: w1 = 7.19 and w2 = 5.30° for
(3), w1 = ꢀ9.77 and w2 = ꢀ7.58° for (4), w1 = 5.26 and w2 = 7.06°
for (5), w1 = 2.62 and w2 = 7.16° for (8) and w1 = ꢀ10.24 and
w2 = ꢀ8.78° for (9) [46]. These values correspond to a moderate
tetrahedral distortion from the ideal square-plane. The six mem-
bered chelate rings involving the Pd atom show a distorted
screw-boat conformation except for the Pd1–N1–C19–C18–C13
ring of (8) when they are evaluated by the classification method
Fig. 7. ORTEP diagram of complex (9) with the atom numbering scheme;
displacement ellipsoids are drawn at the 50% probability level.
ClO4 ion and additional peaks for M+-2ClO4, [Pd(o-Ph2PC6H4CH@N-
R)][ClO4] and [Pd(o-Ph2PC6H4CH@N-R)][ClO4].
for
r = 10 [47]. The mean deviation from the torsion angles be-
tween the closest ideal conformation and found in our complexes
ranges 5–15° (Table 3).
We reported in 2001 [43] the preparation of (9) by a similar
route using KClO4 instead of the silver salt. The characterization
data obtained then are in agreement with the ones presented here,
that are completed with the determination of the molecular struc-
ture by a single-crystal diffraction study. Selected bond distances
and angles are presented in Table 2 and Fig. 7 displays an ORTEP
drawing of the complex cation.
Following the classification of Dance and Scudder [48] for PPh3
based on measures of torsion angles M–P–Cipso–C (Table 4), the
conformation of Pd-PPh2C6H4COR groups is described as no rotor
for complexes (5) and the group Pd1–P2–C–C of (8) and as good ro-
tor for the rest. Compounds (3) and (4) present a set of Ti values
very close to those which would have the ideal rotor
(T1 = T2 = T3 = 44°) (Fig. 8).
The five new structures may be described as planar and their
deviation from the planar coordination has been quantified by
Table 4
Pd–P–Cipso–C torsion angles (°) for three phenyl ring in complexes (3), (4), (5), (8) and (9).
(3)
(4)
(5)
(8)
(9)
Ring 1
Ring 2
Ring 3
128.53
ꢀ48.85
144.40
ꢀ38.13
112.07
ꢀ65.70
ꢀ48.85
ꢀ38.13
ꢀ65.70
ꢀ65.70
ꢀ48.85
ꢀ38.13
16.85
ꢀ49.41
129.42
131.39
ꢀ54.43
ꢀ38.07
144.22
ꢀ49.41
ꢀ54.43
ꢀ38.07
ꢀ54.43
ꢀ49.41
ꢀ38.07
4.52
47.34
ꢀ42.77
144.32
ꢀ59.61
120.42
ꢀ5.95
ꢀ54.11
131.76
145.72
ꢀ30.53
123.57
ꢀ56.90
ꢀ54.11
ꢀ30.53
ꢀ56.90
ꢀ56.90
ꢀ54.11
ꢀ30.53
2.79
ꢀ24.48
157.17
5.74
ꢀ177.46
115.45
ꢀ61.23
ꢀ24.48
5.74
ꢀ61.23
ꢀ61.23
ꢀ24.48
5.74
44.75
44.18
ꢀ139.20
ꢀ139.72
43.54
ꢀ142.86
ꢀ142.27
ꢀ163.01
19.01
16.85
ꢀ163.89
ꢀ122.43
59.21
44.75
16.85
59.21
16.85
44.75
59.21
ꢀ122.80
56.44
54.26
165.34
ꢀ42.77
ꢀ59.61
ꢀ5.95
ꢀ125.19
T (ring 1)
T (ring 2)
T (ring 3)
T1
T2
T3
47.34
43.54
54.26
43.54
47.34
54.26
3.80
44.18
19.01
56.44
19.01
44.18
56.44
25.17
ꢀ59.61
ꢀ42.77
ꢀ5.95
T2–T1
16.84
36.75
27.90
T3–T2
10.72
11.9
6.92
36.82
23.58
30.22
14.46
12.26
Kind of rotor
good rotor
good rotor
good rotor
no rotor
good rotor
no rotor
good rotor
good rotor

G. Sánchez et al. / Inorganica Chimica Acta 363 (2010) 1084–1091
1091
request/cif. Supplementary data associated with this article can
be found, in the online version, at doi:10.1016/j.ica.2009.07.003.
References
[1] A. Bader, E. Lindner, Coord. Chem. Rev. 108 (1991) 27.
[2] G.R. Newkome, Chem. Rev. 93 (1993) 2067.
[3] C.S. Slone, D.A. Weinberger, C.A. Mirkin, Prog. Inorg. Chem. 48 (1999) 233.
[4] P. Braustein, F. Naud, Angew. Chem., Int. Ed. 40 (2001) 680. and references
therein.
[5] P. Braustein, J. Organomet. Chem. 689 (2004) 3953. and references therein.
[6] G.M. Kapteijn, M.P.R. Spee, D.M. Grove, H. Kooijman, A.L. Spek, G. van Koten,
Organometallics 15 (1996) (1405).
[7] P. Braunstein, C. Frison, X. Morise, R.A. Adams, J. Chem. Soc., Dalton Trans.
(2000) 2205.
[8] M.S. Khoshbin, M.V. Ovchinnikov, C.A. Mirkin, L.N. Zakharov, A.L. Rheingold,
Inorg. Chem. 44 (2005) 496. and references therein.
[9] C.W. Rogers, Y. Zhang, B.O. Patrick, W.E. Jones Jr., M.O. Wolf, Inorg. Chem. 41
(2002) 1162.
[10] C.W. Rogers, M.O. Wolf, Coord. Chem. Rev. 233–234 (2002) 341.
[11] C.W. Rogers, M.O. Wolf, Angew. Chem., Int. Ed. 41 (2002) 1898.
[12] M. Kuriyama, K. Nagai, K. Yamada, Y. Miwa, T. Taga, K. Tomioka, J. Am. Chem.
Soc. 124 (2002) 8932.
[13] F.Y. Kwong, W.H. Lam, C.H. Yeung, K.S. Chan, A.S.C. Chan, Chem. Commun.
(2004) 1922.
[14] W-M. Dai, Y. Zhang, Tetrahedron Lett. 46 (2005) 1377.
[15] W.-M. Dai, Y. Li, Y. Zhang, C. Yue, J. Wu, Chem. Eur. J. 14 (2008) 5538.
[16] Z. Weng, S. Teo, T.S.A. Hor, Acc. Chem. Res. 40 (2007).
[17] H.Y. Kwon, S.Y. Lee, B.Y. Lee, D.M. Shin, Y.K. Chung, J. Chem. Soc., Dalton Trans.
(2004) 921.
[18] G. Sánchez, J. García, J.J. Ayllón, J.L. Serrano, L. García, J. Pérez, G. López,
Polyhedron 26 (2007) 2911.
[19] G. Sánchez, J. García, D. Meseguer, J.L. Serrano, L. García, J. Pérez, G. López, J.
Chem. Soc., Dalton Trans. (2003) 4709.
[20] G. Sánchez, J. García, D. Meseguer, J.L. Serrano, L. García, J. Pérez, G. López,
Inorg. Chim. Acta 359 (2006) 1650.
[21] C.A. Ghilardi, S. Midollini, S. Moneti, A. Orlandini, G. Scapacci, J. Chem. Soc.,
Dalton Trans. (1992) 3371.
[22] J.R. Dilworth, S.D. Howe, A.J. Hutson, J.R. Miller, J. Silver, R.M. Thomson, M.
Harman, M.B. Hursthouse, J. Chem. Soc., Dalton Trans. 3553 (1994).
[23] L. Crociani, G. Bandoli, A. Dolmella, M. Basato, B. Corain, Eur. J. Inorg. Chem.
1811 (1998).
[24] K.R. Reddy, C.L. Chen, Y.H. Liu, S.M. Peng, J.T. Chen, S.T. Liu, Organometallics 18
(1999) 2574.
Fig. 8. A drawing of the ideal rotor.
Homoleptic-iminophosphine
Pd(0)
complexes
[Pd(o-
Ph2PC6H4CH@N-R)2] [R = iPr (11), Ph (12)] were obtained by reac-
tion of a fresh dichloromethane solution of these ligands with
Pd(dba)2 at room temperature. It is worth it to point out the low
decomposition temperatures of the new complexes, which are sta-
ble on air for weeks. In contrast with analogous Pd(II) complexes,
their IR spectra display several overlapped absorptions in the car-
bonyl region. The 31P NMR spectra of the new iminophosphine
complexes consist of singlets slightly shifted to high field if com-
pared with related organometallic Pd(II) compounds [42–45] and
the analogous cationic complexes described above.
The proposed formulae of the new complexes are also con-
firmed by FAB mass spectrometry, which displays a different frag-
mentation pattern compared to that of (9) and (10).
[25] S. Doherty, J.G. Knight, T.H. Scanlan, M.R.J. Elsegood, W. Clegg, J. Organometal.
Chem. 650 (2002) 231.
[26] T. Schultz, N. Schmees, A. Pfaltz, Appl. Organometal. Chem. 18 (2004) 595.
[27] K.R. Reddy, K. Surekha, G.H. Lee, S.M. Peng, S.T. Liu, Organometallics 19 (2000)
2637.
4. Conclusion
[28] B. Crociani, S. Antonaroli, A. Marini, U. Matteoli, A. Scrivanti, Dalton Trans.
(2006) 2698.
[29] A. Scrivanti, V. Beghetto, U. Matteoli, S. Antonaroli, A. Marini, F. Mando, R.
Paolesse, B. Crociani, Tetrahedron Lett. 45 (2004) 5861.
[30] A. Scrivanti, V. Beghetto, U. Matteoli, S. Antonaroli, A. Marini, B. Crociani,
Tetrahedron Lett. 61 (2005) 9752.
[31] E. Shirakawa, H. Yoshida, H. Takaya, Tetrahedron Lett. 38 (1997) 3759.
[32] M. Koprowski, R.-M. Sebastin, V. Maraval, M. Zablocka, V. Cadierno, B.
Donnadieu, A. Igau, A.-M. Caminade, J.-P. Majoral, Organometallics 21 (2002)
4680.
[33] E. Shirakawa, T. Hiyama, J. Organomet. Chem. 576 (1999) 169.
[34] A. Scrivanti, U. Matteoli, V. Beghetto, S. Antonaroli, B. Crociani, Tetrahedron 58
(2002) 6881. and references therein.
[35] M.F. Rettig, P.M. Maitlis, Inorg. Synth. 28 (1990) 111.
[36] G.M. Sheldrick, SHELX-97. Programs for Crystal Structure Analysis (Release 97-
2), University of Göttingen, Germany, 1998.
New homoleptic palladium(II) complexes with diphenylphos-
phine-benzamide ligands exhibiting different coordination modes
have been prepared by different synthetic routes and characterized
by spectroscopic techniques and single crystal X-ray diffraction
analysis. Reaction of o-Ph2PC6H4CO–NR with Pd(dba)2 did not yield
the expected Pd0 complexes, unstable under our conditions, and
instead this reaction produced complexes in which a j
2-P,N coor-
dination mode to Pd(II) is observed. Homoleptic iminophosphine
derivatives of both Pd(0) and Pd(II) were readily prepared by direct
reaction of the N^P ligands with whether Pd(dba)2 or labile
[PdCl2(PhCN)2] in presence of AgClO4.
[37] G.M. Sheldrick, SADABS Empirical Absorption Program, University of
Göttingen, Göttingen, Germany, 1996.
[38] B.M. Trost, Acc. Chem. Res 29 (1996) 355.
Acknowledgements
[39] B.M. Trost, B. Breit, M.G. Organ, Tetrahedron Lett. 35 (1994) 5817.
[40] C. Amatore, A. Jutand, L. Mensah, L. Ricard, J. Organomet. Chem. 692 (2007)
1457.
[41] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.
[42] G. Sánchez, J.L. Serrano, M.A. Moral, J. Pérez, E. Molins, G. López, Polyhedron 18
(1999) 3057.
Financial support of this work by Dirección General de Investi-
gación (Project-CTQ2005-09231-C02-01/02) and Fundación Séneca
de la Región de Murcia (Projects 00484/PI/04 and 03010/PI/05) is
gratefully acknowledged.
[43] G. Sánchez, F. Momblona, J. Pérez, G. López, J.L. Serrano, M. Liu, F. Sanz,
Transition Met. Chem. 26 (2001) 100.
[44] G. Sánchez, J.L. Serrano, F. Ruiz, G. López, J. Fluorine Chem. 91 (1998) 165.
[45] G. Sánchez, J.L. Serrano, F. Momblona, F. Ruiz, J. García, J. Pérez, G. López, P.A.
Chaloner, P. Hitchcock, Polyhedron 20 (2001) 571.
Appendix A. Supplementary data
[46] J. Pérez, L. García, E. Pérez, J.L. Serrano, J.F. Martínez, G. Sánchez, G. López, A.
Espinosa, M. Liu, F. Sanz, New J. Chem. 27 (2003) 1490.
[47] J. Pérez, K. Nolsøe, M. Kessler, L. García, E. Pérez, J.L. Serrano, Acta Crystallogr.,
Sect. B B61 (2005) 585.
CCDC 721716, 721717, 721718, 721719 and 721720 contains
the supplementary crystallographic data (3), (4), (5), (8) and (9).
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
[48] I. Dance, M. Scudder, Dalton Trans. (2000) 1579.