Reactivity of cyclometallated semicarbazone complexes of Pd(II): Crystal and molecular structures of [Pd{C6H4C(Et)=NN(H)C(=O)NH2}(PPh 3)][ClO4] and [Pd{C6H4C(Et)=NN(H)C(=O)NH2}{(Ph 2PCH2CH2)2PPh-P,P,P}][Cl]

Article abstract of DOI:10.1016/S0022-328X(99)00629-4

Treatment of the cyclometallated complexes [Pd{4-MeC₆H₃C(Me)=NN(H)C(=O)NH₂}(Cl)] (a), [Pd{C₆H₄C(Et)=NN(H)C(=O)NH₂}(Cl)] (b) and [Pd{3,4-Me₂C₆H₂C(Me)=NN(H)C(=O)NH ₂}(Cl)] (c) with tertiary monophosphine ligands in a complex-phosphine 1:1 molar ratio yielded [C, N] bonded cyclometallated complexes [Pd{4-MeC₆H₃C(Me)=NN(H)C(=O)NH₂}(Cl)(L)] (1a-4a), [Pd{C₆H₄C(Et)=NN(H)C(=O)NH₂}(Cl)(L)] (1b-4b) and [Pd{3,4-Me₂C₆H₂C(Me)=NN(H)C(=O)NH ₂}(Cl)(L)] (1c-4c), [L=PPh₃, PMePh₂, PEtPh₂ and PEt₂Ph]. Reaction of a, b and c with silver perchlorate, prior to the treatment with the monophosphine gave the [C, N, O] bonded cyclometallated complexes [Pd{4-MeC₆H₃C(Me)=NN(H)C(=O)NH₂}(L)][ClO ₄] (5a-8a), [Pd{C₆H₄C(Et)=NN(H)C(=O)NH₂}(L)][ClO ₄] (5b-8b) and [Pd{3,4-Me₂C₆H₂C(Me)=NN(H)C(=O)NH ₂}(L)][ClO₄] (5c-8c). Reaction of a, b and c with tertiary monophosphines in a complex-phosphine 1:2 ratio gave the C only bonded non-cyclometallated complexes [Pd{4-MeC₆H₃C(Me)=NN(H)C(=O)NH₂}(PEt ₂Ph)₂(Cl)] (9a), [Pd{C₆H₄C(Et)=NN(H)C(=O)NH₂}(PPh ₃)₂(Cl)] (9b) and [Pd{3,4-Me₂C₆H₂C(Me)=NN(H)C(=O)NH ₂}(PEt₂Ph)₂(Cl)] (9c). Treatment of a, b and c with the triphosphine bis(2-diphenylphosphinoethyl)phenylphosphine (trifos) yielded the non-cyclometallated complexes [Pd{4-[MeC₆H₃C(Me)=NN(H)C(=O)NH₂}{L-P,P,P}][Cl] (10a), [Pd{C₆H₄C(Et)=NN(H)C(=O)NH₂}{L-P,P,P}][Cl] (10b) and [Pd{3,4-Me₂C₆H₂C(Me)=NN(H)C(=O)NH ₂}{L-P,P,P}][Cl] (10c) (L=(Ph₂PCH₂CH₂)₂PPh). The complexes were characterised by their elemental analysis (C, H, N) and by IR and ³¹P-{¹H} and ¹H-NMR spectroscopy. [Pd{C₆H₄C(Et)=NN(H)C(=O)NH₂}(PPh ₃)][ClO₄] (5b) and [Pd{C₆H₄C(Et)=NN(H)C(=O)NH₂}{(Ph ₂PCH₂CH₂)₂PPh-P,P,P}][Cl] (10b) were characterised crystallographically.

Full text of DOI:10.1016/S0022-328X(99)00629-4

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 598 (2000) 1–12
Reactivity of cyclometallated semicarbazone complexes of Pd(II):
crystal and molecular structures of [Pd{C6H4C(Et)ꢀ
NN(H)C(ꢀO)NH2}(PPh3)][ClO4] and [Pd{C6H4C(Et)ꢀ
NN(H)C(ꢀO)NH2}{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]
Alberto Ferna´ndez a, Margarita Lo´pez-Torres a, Antonio Sua´rez a, Juan M. Ortigueira b,
Teresa Pereira b, Jesu´s J. Ferna´ndez a, Jose´ M. Vila b,*, Harry Adams c
a Departamento de Qu´ımica Fundamental e Industrial, Uni6ersidad de La Corun˜a, E-15071 La Corun˜a, Spain
b Departamento de Qu´ımica Inorga´nica, Uni6ersidad de Santiago de Compostela, E-15706 Santiago de Compostela, Spain
c Department of Chemistry, The Uni6ersity, Sheffield S3 7HF, UK
Received 5 August 1999; received in revised form 14 October 1999
Abstract
Treatment of the cyclometallated complexes [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}(Cl)] (a), [Pd{C6H4C(Et)ꢀNN(H)-
C(ꢀO)NH2}(Cl)] (b) and [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}(Cl)] (c) with tertiary monophosphine ligands in a complex–
phosphine 1:1 molar ratio yielded [C, N] bonded cyclometallated complexes [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(L)] (1a–4a), [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(Cl)(L)] (1b–4b) and [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}(Cl)(L)]
(1c–4c), [L=PPh3, PMePh2, PEtPh2 and PEt2Ph]. Reaction of a, b and c with silver perchlorate, prior to the treatment with the
monophosphine gave the [C, N, O] bonded cyclometallated complexes [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(L)][ClO4] (5a–8a), [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(L)][ClO4] (5b–8b) and [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}(L)]-
[ClO4] (5c–8c). Reaction of a, b and c with tertiary monophosphines in a complex–phosphine 1:2 ratio gave the C only bonded
non-cyclometallated complexes [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}(PEt2Ph)2(Cl)] (9a), [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
(PPh3)2(Cl)] (9b) and [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}(PEt2Ph)2(Cl)] (9c). Treatment of a, b and c with the triphos-
phine bis(2-diphenylphosphinoethyl)phenylphosphine (trifos) yielded the non-cyclometallated complexes [Pd{4-[MeC6H3C-
(Me)ꢀNN(H)C(ꢀO)NH2}{L-P,P,P}][Cl] (10a), [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}{L-P,P,P}][Cl] (10b) and [Pd{3,4-Me2C6H2C-
(Me)ꢀNN(H)C(ꢀO)NH2}{L-P,P,P}][Cl] (10c) (L=(Ph2PCH2CH2)2PPh). The complexes were characterised by their elemental
analysis (C, H, N) and by IR and 31P-{1H} and 1H-NMR spectroscopy. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(PPh3)][ClO4] (5b) and
[Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}{(Ph2PCH2CH2)2PPh-P,P,P}][Cl] (10b) were characterised crystallographically. © 2000
Elsevier Science S.A. All rights reserved.
Keywords: Cyclometallated; Semicarbazone; Palladium
pounds show important applications, such as their use
in regiospecific organic and organometallic reactions
1. Introduction
[6], in insertion reactions [7] and in the synthesis of new
metal mesogenic compounds [8] and catalytic materials
[9]. Nitrogen donor ligands are known to undergo facile
cyclometallation. In previous work, we have shown that
potentially terdentate lignads such as Schiff bases
[10,11], semicarbazones [12] and thiosemicarbazones
Since the first cyclometallated complex was synthe-
sised, cyclometallation has become an important part of
organometallic chemistry and several reviews covering
the subject have appeared [1–5]. Cyclometallated com-
* Corresponding author.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00629-4

2
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
[13] undergo facile metallation with palladium(II), pal-
ladium(0) and platinum(II) to give compounds with
two five-membered fused rings at the metal centre (Fig.
1).
2.1.1. PdꢁO bond clea6age
Treatment of the cyclometallated compounds a, b
and c with tertiary monophosphines (see Scheme 1) in
1:1 molar ratio gave the complexes [Pd{4-MeC6H3C-
(Me)ꢀNN(H)C(ꢀO)NH2}(Cl)(L)] (1a–4a), [Pd{C6H4-
C(Et)ꢀNN(H)C(ꢀO)NH2}(Cl)(L)] (1b–4b) and [Pd{3,4-
When [C, N, O] and [C, N, N] derivatives are treated
with neutral ligands, such as tertiary phosphines cleav-
age of the oxygenꢁmetal or of the nitrogenꢁmetal bonds
occurs prior to the ring-opening of the five-membered
metallacycle upon continued reaction with the corre-
sponding phosphine. If the cyclometallated compound
is treated first with a silver(I) salt, the chloride ligand is
removed from as silver chloride and the vacant co-ordi-
nation site is occupied by the phosphine. Reactivity of
the [C, N, S] derivatives is clearly different to that
shown by [C, N, O] and [C, N, N] derivatives. This
stems from the distinct nature of the compounds. On
the one hand, the semicarbazone compounds are usu-
ally mononuclear species II and the thiosemicarbazone
ones are tetramers III, and on the other, the
PdꢁSchelating bond is sufficiently strong to hinder cleav-
age by nucleophiles; this always gives compounds with
two fused five-membered rings at the metal. Herein, we
report the reactivity of semicarbazone cyclometallated
compounds which can be directed to cleavage of: (a)
only the PdꢁO bond; (b) the PdꢁCl bond with substitu-
tion of the chloride ligand; (c) the PdꢁO and PdꢁN
bonds; and (d) the PdꢁO, PdꢁN and PdꢁCl bonds,
simultaneously. The first three cases (a, b) and (c), may
be modelled by reaction with tertiary monophosphines,
and the last one (d), proceeds via reaction with triphos-
phines such as bis(2-diphenylphosphinoethyl)phenyl-
phosphine (triphos). The crystal structures of two com-
pounds pertaining to cases (b) and (d) are described; an
interesting feature of the latter is the close contact, in
the solid state, between the palladium atom and the
imino nitrogen atom.
Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}(Cl)(L)]
(1c–4c)
[L=PPh3, PMePh2, PEtPh2 and PEt2Ph]. The com-
pounds were pure air-stable solids which were fully
characterised (see Section 3 and Table 1). The w(CꢀO)
stretching frequency was shifted from its position in the
IR spectra of the starting material, a–c, to higher
frequency, i.e. a value similar to the one in the free
ligand. Also, the NH resonance in the 1H-NMR spectra
was shifted to lower frequency and its value was close
to that in the spectra of the ligands. These findings are
in accordance with the presence of an unco-ordinated
CꢀO group formed upon PdꢁO bond cleavage and
opening of the PdNNCO ring [12,14].
The H5 proton resonance was shifted to a lower
frequency and also showed coupling to the 31P nucleus
with 4J(PH5) values in the range 5.2–6.4 Hz. The
1
C(4)ꢁMe signal in the H-NMR spectra of compounds
1a–4a and 1c–4c showed a strong upfield shift, ca. 0.6
ppm, due to shielding by a phenyl ring from the
phosphine [15]. This implies that the phosphine ligand
is in a cis position to the metallated ring, thus placing
the chloride ligand trans to the metallated carbon atom.
Therefore, the incoming phosphine imposes a rear-
rangement of the co-ordinated atoms on the palladium
metal. Further proof was given by the phosphorus
resonance in the 31P-{1H}-NMR spectra, which was in
accordance with a phosphorus-to-nitrogen trans geome-
try [16]; and also, by the w(PdꢁCl) stretching mode,
typical of a chloride ligand trans to a ligand of high
trans influence such as the phenyl carbon atom.
2.1.2. PdꢁCl bond clea6age through chlorine
abstraction
2. Results and discussion
Treatment of compounds a, b and c with silver
perchlorate followed by the appropriate tertiary
monophosphine in 1:1 molar ratio gave the mononu-
clear compounds [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)-
NH2}(L)][ClO4] (5a–8a), [Pd{C6H4C(Et)ꢀNN(H)C-
(ꢀO)NH2}(L)][ClO4] (5b–8b) and [Pd{3,4-Me2C6H2C-
(Me)ꢀNN(H)C(ꢀO)NH2}(L)][ClO4] (5c–8c) [L=PPh3,
PMePh2, PEtPh2 and PEt2Ph] as air-stable solids which
were fully characterised (see Section 3 and Table 1).
They were 1:1 electrolytes as was shown by molar
conductivity measurements in dry acetonitrile. Both the
w(CꢀO) stretching frequency in the IR spectra and the
2.1. Reacti6ity of the cyclometallated complexes
The compounds described in this paper were charac-
terised by elemental analysis and by IR spectroscopy
(data in Section 3) and by 1H- and 31P-{1H}-NMR
spectroscopy (Table 1).
1
resonance assigned to the NH proton in the H-NMR
spectra were in agreement with PdꢁO and PdꢁN co-or-
dination [12,14] (see Section 3 and Table 1). Thus, the
palladium atom is co-ordinated to the imine nitrogen
atom and to the oxygen atom of the semicarbazone
Fig. 1.

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
3
Table 1
31P- a and 1H-NMR b data c,d
Compound
31P
Aromatic
Others
e
Ligand
7.60[d, 2H, H2, H6, 8.2 f]
7.21[d, 2H, H3, H5, 8.2 f]
8.80[br, 1H, NH]
6.4[br, 2H, NH2]
2.38[s, 3H, Me]
2.28[s, 3H, Me]
10.2[br, 1H, NH]
2.21[s, 3H, Me]
a e
6.83–7.15[m, 3H, H2, H3, H5]
2.18[s, 3H, Me]
1a e
37.0 s
21.5 s
33.8 s
33.0 s
35.5 s
18.4 s
7.01[d, 1H, H2, 7.7 f]
6.74[d, 1H, H3, 7.7 f]
5.97[d, 1H, H5, 5.4 g]
9.3[br, 1H, NH]
6.7[br, 2H, NH2]
2.45[s, 3H, Me]
1.70[s, 3H, Me h]
9.0[br, 1H, NH]
6.9[br, 2H, NH2]
2.21[s, 3H, Me]
2a e,k
3a e
4a
7.22[d, 1H, H2, 7.5 f]
5.95[d, 1H, H5, 6.2 g]
7.21[d, 1H, H2, 7.7 f]
6.05[d, 1H, H5, 5.8 g]
1.66[s, 3H, Me h]
9.0[br, 1H, NH]
6.7[br, 2H, NH2]
2.21[s, 3H, Me]
1.64[s, 3H, Me h]
9.8[br, 1H, NH]
5.0[br, 2H, NH2]
2.42[s, 3H, Me]
7.17[d, 1H, H2, 7.7 f]
6.79[d, 1H, H3, 7.7 f]
6.18[d, 1H, H5, 6.0 g]
1.90[s, 3H, Me h]
10.61[s, 1H, NH]
5.1[br, 2H, NH2]
2.35[s, 3H, Me]
5a
6.94[d, 1H, H2, 7.7 f]
6.76[d, 1H, H3, 7.7 f]
5.88[d, 1H, H5, 5.0 g]
1.74[s, 3H, Me h]
10.62[d, 1H, NH, 4.6 m
5.2[br, 2H, NH2]
2.32[s, 3H, Me]
6a k
6.93[d, 1H, H2, 7.7 f]
6.78[d, 1H, H3, 7.7 f]
6.00[d, 1H, H5, 5.3 g]
]
1.87[s, 3H, Me h]
10.63[d, 1H, NH, 4.5 m
2.38[s, 3H, Me]
7a
8a
32.1 s
32.2 s
6.93[d, 1H, H2, 7.7 f]
6.77[d, 1H, H3, 7.7 f]
5.99[d, 1H, H5, 4.3 g]
6.90[d, 1H, H2, 7.7 f]
6.76[d, 1H, H3, 7.7 f]
5.99[d, 1H, H5, 5.0 g]
]
]
1.78[s, 3H, Me h]
10.62[d, 1H, NH, 4.4 m
5.8[br, 2H, NH2]
2.31[s, 3H, Me]
1.83[s, 3H, Me h]
8.9 n[br, 1H, NH]
4.8[br, 2H, NH2]
2.08[s, 3H, Me]
9a
8.1 s
6.88[d, 1H, H2, 7.7 f]
6.63[d, 1H, H3, 7.7 f]
6.76[s, 1H, H5]
1.65[s, 3H, Me h]
11.5[br, 1H, NH]
5.5[br, 2H, NH2]
2.36[s, 3H, Me]
10a
85.8 t
41.3 d
6.59[d, 1H, H3, 7.7 f]
5.67[d, 1H, H5, 6.9 g]
1.57[s, 3H, Me h]
9.64[br, 1H, NH]
6.57[s, 2H, NH2]
2.72[q, 2H, Et, 7.5 f]
1.19[t, 3H, Et, 7.5 f]
10.6 [br, 1H, NH]
2.63[q, 2H, Et, 7.5 f]
1.11[t, 3H, Et, 7.5 f]
9.5 n[br, 1H, NH]
6.82n[s, 2H, NH2]
2.91[q, 2H, Et, 7.6 f]
1.38[t, 3H, Et, 7.6 f]
9.0 n[br, 1H, NH]
6.7 n[br, 2H, NH2]
2.87[q, 2H, Et, 7.5 f]
1.33[t, 3H, Et, 7.5 f]
Ligand e
7.82[dd, 1H, H2, 7.8 f, 1.4 i]
7.36[m, H3, H4, H5, H6,]
b e
1b
7.3–6.9[m, 4H]
35.7 s
20.3 s
7.09[d, 1H, H2, 7.4 f]
6.96[t, 1H, H3, 7.4f]
6.55[dt, 1H, H4, 7.4 f, 1.3 i]
6.20[dd, 1H, H5, 7.4 f, 6.2 g]
7.21[d, 1H, H2, 7.4 f]
2b k
6.96[t, 1H, H3, 7.4 f]
6.63[t, 1H, H4, 7.4 f]
6.38[dd, 1H, H5, 7.4 f, 5.8 g]

4
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
Table 1 (Continued)
Compound
31P
Aromatic
Others
3b
32.9 s
7.57[d, 1H, H2, 7.5 f]
9.2 n[br, 1H, NH]
6.7 n[br, 2H, NH2]
2.71[q, 2H, Et, 7.6 f]
1.16[t, 3H, Et, 7.6 f]
9.2 n[br, 1H, NH]
6.7 n[br, 2H, NH2]
2.82[q, 2H, Et, 7.8 f]
1.27[t, 3H, Et, 7.8 f]
10.72[d, 1H, NH, 4.7 m
4.9[br, 2H, NH2]
6.95[t, 1H, H3, 7.5 f]
6.59[t, 1H, H4, 7.5 f]
6.37[dd, 1H, H5, 7.5 f, 5.2 g]
7.13[dd, 1H, H2, 7.4 f, 1.3 i]
6.96[dt, 1H, H3, 7.4 f, 0.6 i]
6.63[dt, 1H, H4, 7.4 f, 1.3 i]
6.38[m, 1H, H5, 7.4 f, 0.6 i, 5.2 g]
7.08[dd, 1H, H2, 7.6 f, 1.5 i]
6.98[dt, 1H, H3, 7.6 f, 0.7 i]
6.58[dt, 1H, H4, 7.6 f, 1.5 i]
6.19[m, 1H, H5, 7.6 f, 0.7 i, 5.3 g]
7.08[d, 1H, H2, 7.5 f]
4b
32.3 s
35.4 s
18.7 s
32.2 s
32.6 s
9.0 s
5b
]
2.77[q, 2H, Et, 7.6 f]
1.35[t, 3H, Et, 7.6 f]
10.7[br, 1H, NH]
6b k
7b
6.99[t, 1H, H3, 7.5 f]
6.0[br, 2H, NH2]
6.70[t, 1H, H4, 7.5 f]
2.75[q, 2H, Et, 7.6 f]
1.32[t, 3H, Et, 7.6 f]
10.9[br, 1H, NH]
6.32[dd, 1H, H5, 7.5 f, 6.4 g]
7.06[dd, 1H, H2, 7.6 f, 1.6 i]
6.97[dt, 1H, H3, 7.6 f, 0.7 i]
6.66[dt, 1H, H4, 7.6 f, 1.6 i]
6.30[m, 1H, H5, 7.6 f, 0.7 i, 5.3 g]
7.06[dd, 1H, H2, 7.6 f, 1.8 i]
6.99[t, 1H, H3, 7.6 f]
6.0[br, 2H, NH2]
2.78[q, 2H, Et, 7.7 f]
1.34[t, 3H, Et, 7.7 f]
10.74[d, 1H, NH, 4.5 m
5.2[br, 2H, NH2]
8b
]
6.73[dt, 1H, H4, 7.6 f, 1.8 i]
6.28[dd, 1H, H5, 7.6 f, 5.0 g]
2.74[q, 2H, Et, 7.6 f]
1.33[t, 3H, Et, 7.6 f]
9.5 n[d, 1H, NH]
9b
6.92[t, 1H, H3, 7.6 f]
6.81 n[s, 2H, NH2]
2.72[q, 2H, Et, 7.5 f]
1.27[t, 3H, Et, 7.5 f]
10.8[br, 1H, NH]
6.52[dt, 1H, H4, 7.6 f, 1.1 i]
6.42[d, 1H, H5, 7.6 f]
10b
Ligand e
86.4 t
41.4 d
6.82[t, 1H, H3, 7.5 f]
6.39[t, 1H, H4, 7.5 f]
5.98[t, 1H, H5, 7.5 f, 7.5 g]
7.45[s, 1H, H2]
5.3[br, 2H, NH2]
1.09[t, 3H, Et, 7.6 f]
9.2[br, 1H, NH]
6.4[br, 2H, NH2]
2.30[s, 3H, Me]
2.29[s, 3H, Me]
2.19[s, 3H, Me h]
10.1[br, 1H, NH]
2.17[s, 3H]
7.40[d, 1H, H6, 7.7 f]
7.14[d, 1H, H5, 7.7 f]
c e
1c
7.1–6.8 m
2.13[br, 6H]
36.0 s
21.0 s
33.7 s
32.1 s
35.2 s
6.87[s, 1H, H2]
9.2 n[br, 1H, NH]
6.7 n[br, 2H, NH2]
2.18[s, 3H, Me]
2.08[s, 3H, Me]
1.61[s, 3H, Me h]
8.95[s, 1H, NH]
6.7[br, 2H, NH2]
2.20[s, 3H, Me]
2.02[s, 3H, Me]
1.56[s, 3H, Me h]
9.0[br, 1H, NH]
6.7[br, 2H, NH2]
2.22[s, 3H, Me]
2.02[s, 3H, Me]
1.56[s, 3H, Me h]
9.0[br, 1H, NH]
6.7[br, 2H, NH2]
2.18[s, 3H, Me]
2.03[s, 3H, Me]
1.72[s, 3H, Me h]
10.58[d, 1H, NH, 4.3 m
4.3[br, 2H, NH2]
5.89[d, 1H, H5, 5.4 g]
2c e,k
3c e
4c e
5c
7.11[s, 1H, H2]
5.90[d, 1H, H5, 6.4 g]
7.11[s, 1H, H2]
5.99[d, 1H, H5, 6.0 g]
7.08[s, 1H, H2]
6.06[d, 1H, H5, 6.0 g]
6.80[s, 1H, H2]
]
5.81[d, 1H, H5, 5.2 g]

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
5
Table 1 (Continued)
Compound
31P
Aromatic
Others
2.35[s, 3H, Me]
2.10[s, 3H, Me]
1.64[s, 3H, Me h]
10.64[d, 1H, NH, 4.5 m
5.0[br, 2H, NH2]
2.33[s, 3H, Me]
6c k
18.8 s
33.3 s
32.3 s
8.36 s
6.80[s, 1H, H2]
]
]
]
5.92[d, 1H, H5, 5.3 h]
2.10[s, 3H, Me]
1.67[s, 3H, Me h]
10.65[d, 1H, NH, 4.5 m
5.1[br, 2H, NH2]
2.34[s, 3H, Me]
7c
6.79[s, 1H, H2]
5.92[d, 1H, H5, 5.1 g]
2.09[s, 3H, Me]
1.79[s, 3H, Me h]
10.62[d, 1H, NH, 4.5 m
5.0[br, 2H, NH2]
2.32[s, 3H, Me]
8c
6.79[s, 1H, H2]
5.94[d, 1H, H5, 5.0 g]
2.10[s, 3H, Me]
1.83[s, 3H, Me h]
8.8 n[br, 1H, NH]
4.5[br, 2H, NH2]
2.28[s, 3H, Me]
9c
6.65[s, 1H, H2]
6.77[s, 1H, H5]
2.19[s, 3H, Me]
1.99[s, 3H, Me h]
10.6[br, 1H, NH]
5.1[br, 2H, NH2]
2.29[s, 3H, Me]
10c
87.7 t
43.0 d
5.56[d, 1H, H5, 8.9 g]
2.03[s, 3H, Me]
1.75[s, 3H, Me h]
a In CDCl3 unless otherwise stated. Measured at 100.6 MHz (ca.920°C); chemical shifts (l) in ppm (90.1) to high frequency of 85% H3PO4.
b In CDCl3 unless otherwise stated. Measured at 250 or 300 MHz; chemical shifts (l) in ppm (90.01) to high frequency of SiMe4.
c Coupling constants in Hz.
d s, singlet; d, doublet; dd, doublet of doublets; t, triplet; dt doublet of triplets; q, quadruplet; m, multiplet; br, broad. The metallated phenyl
ring carbon atoms are numbered from 1 (semicarbazone functionality) to 6 (metallated carbon).
e In DMSO-d6.
f 3J(HH).
g 4J(PH).
h C(4)ꢁMe.
i 4J(HH).
2
k l(CH3PPh2)=2.19 d (2a), 2.11 d (6a), 2.14 d (2b), 2.10 d (6b), 2.18 d (2c), 2.10 d (6c); J(CH3P)=10.5 (2a), 9.4 (6a), 10.0 (2b), 9.7 (6b), 10.6
(2c), 10.4 (6c).
m 4J(PNH).
n Signal taken from a spectrum in DMSO-d6.
ligand, giving compounds with two fused five-mem-
bered rings at the metal. The phosphine ligand occupies
the fourth co-ordination site which was left vacant after
the removal of the chloride ligand. The absence of the
w(PdꢁCl) stretching mode in the IR spectra of the
complexes ascertains that chloride was removed quanti-
tatively. The H5 proton resonance shows coupling to
the 31P nucleus, ca. 6.4–4.3 Hz, and was shifted to a
lower frequency, in accordance with the above results.
An alternative route to the synthesis of these com-
plexes was the treatment of compounds 1a–4a, 1b–4b
or 1c–4c, as appropriate, with silver perchlorate; upon
removal of the chloride ligand, the oxygen atom occu-
pies the vacant co-ordination site trans to carbon. The
X-ray structure of complex 5a was solved confirming
the spectroscopic data.
2.1.3. PdꢁO and PdꢁN bond clea6age
Reaction of complexes a, b and c with tertiary
monophosphines in a 1:2 ratio gave the non-cyclo-
metallated complexes [Pd{4-MeC6H3C(Me)ꢀNN(H)C-
(ꢀO)NH2}(PEt2Ph)2(Cl)] (9a), [Pd{C6H4C(Et)ꢀNN-
(H)C(ꢀO)NH2}(PPh3)2(Cl)] (9b) and [Pd{3,4-Me2C6-
H2C(Me)ꢀNN(H)C(ꢀO)NH2}(PEt2Ph)2(Cl)] (9c). The
w(CꢀO) stretching frequency ca. 1690 cm−1 and the
NH resonance of ca. 9.0 ppm seem to indicate that the
PdꢁO bond is absent in the complexes. Furthermore, no
coupling of the H5 proton resonance to the 31P nucleus

6
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
point to complexes, where the PdꢁO and PdꢁN bonds
have been cleaved, so that the organic ligand is bonded
to the metal atom solely by the |PdꢁC bond. The
PdꢁCl bond remains, but the chloride ligand has
changed its co-ordination position from cis to carbon
to trans to carbon, a geometry imposed by the incom-
ing phosphine ligands.
was observed. This is attributable to cleavage of the
PdꢁN bond and consequent opening of the five-mem-
bered ring, so that, the metallated phenyl ring may
rotate freely about the PdꢁC bond bringing its plane at
90° to the palladium co-ordination plane [16]. A singlet
resonance was observed in the 31P-{1H}-NMR spectra
of the complexes indicating a PꢁPdꢁP trans geometry.
Its value was strongly shifted to a lower frequency as
compared to the compounds with the phosphine trans
to the nitrogen, which reflects the stronger trans influ-
ence of phosphorus as opposed to nitrogen. These data
2.1.4. PdꢁO, PdꢁN and PdꢁCl bond clea6age
Treatment of a, b and c with the phosphine bis(2-
diphenylphosphinoethyl)phenylphosphine in 1:1 molar
ratio yielded the complexes [Pd{4-MeC6H3C(Me)ꢀ
NN(H)C(ꢀO)NH2}{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]-
(10a), [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}{(Ph2PCH2-
CH2)2PPh-P,P,P}][Cl] (10b) and [Pd{3,4-Me2C6H2C-
(Me)ꢀNN(H)C(ꢀO)NH2}{(Ph2PCH2ꢁCH2)2PPh-P,P,
P}][Cl] (10c). The compounds were 1:1 electrolytes as
shown by the conductivity measurements in dry ace-
tonitrile. The phosphorus resonances in the 31P-{1H}-
NMR spectra were downfield shifted from their values
in the free phosphine suggesting co-ordination of the
phosphorus atoms to the metal centre. A triplet signal
was assigned to the central 31P nucleus, which was trans
to the phenyl carbon atom, and a doublet was assigned
to the two equivalent mutually trans phosphorus nuclei,
which appeared at a lower frequency in accordance
with the high trans influence of the phosphine ligand
[17]. The H5 proton resonance was coupled to the
4
central phosphorus nucleus only with J(PH5) in the
range 8.9–6.9 Hz; no coupling was observed between
H5 and the two terminal phosphorus nuclei in accor-
dance with the ca. 90° angle between the metallated
phenyl ring and the palladium co-ordination plane.
These observations agree with co-ordination of the
palladium atom to the carbon atom and to three phos-
phorus atoms with subsequent PdꢁO, PdꢁN and PdꢁCl
bond cleavage as shown by the value of the w(CꢀO)
stretching frequency and the absence of w(PdꢁCl). Sur-
Scheme 1. (i) PR3 (acetone, 1:1 ratio); (ii) AgClO4, PR3 (acetone); (iii)
AgClO4; (iv) PR3 (acetone, 1:2 ratio); (v) triphos (acetone).
1
prisingly, the NH resonance in the H-NMR spectra
showed a downfield shift from its value in the spectra of
the free ligands. These findings were confirmed by the
X-ray crystal structure resolution of one of the com-
pounds, 10b.
2.1.5. Crystal structure of [Pd{C6H4C(Et)ꢀ
NN(H)C(ꢀO)NH2}(PPh3)][ClO4] (5b)
Suitable crystals of the title compound were grown
by slowly evaporating a chloroform solution. The
molecular structure is illustrated in Fig. 2. Crystal data
are given in the Table 2 and selected bond distances
and angles with estimated standard deviations are
shown in Table 3.
The crystal structure comprises the cation 5b, a
perchlorate ion and a chloroform molecule. The palla-
Fig. 2. Molecular structure of [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
(PPh3)][ClO4] (5b).

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
7
Table 2
tively. Angles between planes are as follows: plane
1/plane 2=0.8°; plane 1/plane 3=2.3°; plane 2/plane
3=2.1°.
In the solid state the molecules of 5b are bridged by
the perchlorate counterion which forms hydrogen
bonds with the thiosemicarbazone N(2) and N(3) hy-
drogen atoms (see Fig. 3) (N(2)ꢁH(2A)···O(4), 2.827(9)
Crystal data and structure refinement
5b
10b
Formula
C29H28N3O5PCl4Pd
C46.63H47.63N3OP3-
Cl8.88Pd
1179.93
293(2)
0.71073
Orthorhombic
Pna21
Mr
777.71
293(2)
0.71073
Monoclinic
P21/n
Temperature (K)
Wavelength (A)
Crystal system
Space group
Cell dimensions
,
,
A, H(2A)···O(4), 1.97 A, 158.5°; N(3)ꢁH(3A)···O(3),
,
,
,
3.100(9) A, H(3A)···O(3), 2.22 A, 168.8°; N(3)ꢁH(3B)···
,
,
O(5), 3.177(12) A, H(3B)···O(5), 2.31 A, 161.0°;
,
N(3)ꢁH(3B)···O(2), 3.367(14), H(3B)···O(2), 2.57 A,
148.5°). The H-bonded molecules are stacked in
pseudo-parallel polymeric planes.
,
a (A)
11.2771(2)
13.2373(1)
22.2874(3)
96.6457(9)
3304.67(8)
4
0.975
0.60×0.50×0.40
56
38.364(8)
11.292(6)
25.122(5)
90
10883(7)
8
0.902
0.64×0.40×0.30
,
b (A)
,
c (A)
i (°)
2.1.6. Crystal structure of [Pd{C6H4C(Et)ꢀNN(H)C-
(ꢀO)NH2}{(Ph2PCH2CH2)2PPh-P,P,P}][Cl] (10b)
Suitable crystals of the title compound were grown
by slowly evaporating a chloroform solution. The
molecular structure is illustrated in Fig. 4. Crystal data
are given in the Table 2 and selected bond distances
and angles with estimated standard deviations are
shown in Table 3.
The structure of 10b comprises two, almost identical,
discrete [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}{(Ph2PCH2-
CH2)2PPh-P,P,P}]+ cations, two chloride anions and
five full-occupancy and one 25% occupancy chloroform
solvent molecules. The palladium(II) is bonded to four
atoms: three phosphorus from the terdentate bis(2-
diphenylphosphinoethyl)phenylphosphine and to the
ortho carbon atom of the semicarbazone. A short con-
tact between the N(1) imino carbon atom and the
palladium atom is observed (Pd(1)ꢁN(1) and Pd(2)ꢁ
N(1a) distances of 2.61(1) and 2.59(1)°, respectively) far
3
,
V (A )
Z
v (mm−1
)
Crystal size (mm)
2qmax (°)
Reflections:
collected
unique
Transmissions
45
22784
7942 (Rint=0.13)
1.00, 0.72
7804
6639 (Rint=0.04)
No absorption
correction
674
1.012
0.0721
0.1724
0.001
0.660
No. of parameters
S
388
1.009
0.0607
0.1605
0.001
1.102
R [F, I\2|(I)]
wR [F2, all data]
Max. D/|
Max. z (e A
−3
,
)
dium(II) atom is bonded to the aryl carbon C(1), the
imine nitrogen N(1) and the oxygen O(1) of the semi-
carbazone ligand and to a phosphorus atom of the
triphenylphosphine ligand P(1).
The PdꢁN(1) bond distance of 2.017(4) A is within
the expected value based on the sum of the covalent
,
from the PdꢁN bond length of 2.23(2) A in an authentic
five-co-ordinate Pd(II) complex [21]. Such weak interac-
,
,
tions in the range 2.576(4)–2.805(5) A have been de-
scribed before [22]. As consequence of this
2
a
,
radii [18] of palladium (1.31 A) and nitrogen (sp ) (0.7
interaction, the square planar geometry around the
palladium atom is severely distorted.
,
A) and similar to other distances reported [12,19]. The
,
PdꢁC(1), 2.002(5) and Pd(1)ꢁP(1), 2.275(1) A, bond
,
The palladium atom is 0.486 A out of the plane
distances are somewhat shorter than the values pre-
dicted from their covalent radii [18], but similar to
values found earlier [12,19]. The PdꢁO(1) bond distance
through P(1), P(2), P(3), C(5) (plane 1, r.m.s.=0.0086
,
A). C(5)ꢁPd(1)ꢁP(2) and P(3)ꢁPd(1)ꢁP(1) bond angles
of 171.2(6) and 154.9(2)° show the mentioned distor-
tion. The metallated phenyl ring is planar (C(5), C(6),
,
,
(2.168(4) A) is longer than the expected value of 1.97 A,
and shows the trans influence of the aryl carbon atom
and similar to others reported [12]. The C(8)ꢁO(1),
1.257(6) A and N(1)ꢁN(2), 1.374(6) A bond distances
are similar to the values found in non-co-ordinated
semicarbazone ligands [20]. The sum of angles about
the palladium atom is 359.99° with the only noteworthy
deviation being the somewhat reduced [N(1)ꢁ
Pd(1)ꢁC(1)] bond angle consequent upon chelation.
The geometry around the palladium atom is planar
,
C(7), C(8), C(9), C(10); plane 2, r.m.s.=0.0080 A) and
forms an angle with plane 1 of 105.0°. The Pd(1)ꢁC(5)
,
,
,
bond length, 2.093(18) A is longer than the Pd(1)ꢁC(1),
2.002(5) bond distance as a consequence of the trans
influence of the phosphorus atom. The PdꢁP bond
,
,
lengths (Pd(1)ꢁP(1), 2.323(6) A; Pd(1)ꢁP(2), 2.283(6) A;
,
Pd(1)ꢁP(3), 2.289(6) A) are similar to those found in
related Pd(II) complexes [23] and suggest that slightly
partial double bond between the palladium an phos-
phorus atoms may exist [24].
,
(r.m.s.=0.0118 A; plane 1). The metallated ring [Pd,
C(1), C(6), C(7), N(1)] and the co-ordination ring [Pd,
N(1), N(2), C(8), O(1)] are also planar (r.m.s.=0.0181
The molecular units are stacked in dimers held to-
gether by intermolecular hydrogen bonding (see Fig.
5) between one amido hydrogen and the oxygen
,
,
A; plane 2) and (r.m.s.=0.0145 A; plane 3), respec-

8
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
Table 3
,
Selected bond distances (A) and angles (°) for complexes 5b and 10b
5b
10b
Bond distances
Pd(1)ꢁC(1)
Pd(1)ꢁN(1)
Pd(1)ꢁO(1)
Pd(1)ꢁP(1)
O(1)ꢁC(8)
N(1)ꢁC(7)
N(1)ꢁN(2)
N(2)ꢁC(8)
N(3)ꢁC(8)
2.002(5)
2.017(4)
2.168(4)
2.275(1)
1.257(6)
1.284(6)
1.374(6)
1.366(7)
1.321(7)
Pd(1)ꢁC(5)
Pd(1)ꢁP(2)
Pd(1)ꢁP(3)
Pd(1)ꢁP(1)
Pd(1)ꢁN(1)
N(1)ꢁC(11)
N(1)ꢁN(2)
N(2)ꢁC(12)
N(3)ꢁC(12)
O(1)ꢁC(12)
2.09(1)
2.283(6)
2.289(6)
2.323(6)
2.61(1)
1.24(2)
1.38(2)
1.39(3)
1.35(3)
1.20(3)
Pd(2)ꢁC(5A)
Pd(2)ꢁP(2A)
Pd(2)ꢁP(1A)
Pd(2)ꢁP(3A)
Pd(2)ꢁN(1A)
N(1A)ꢁC(11A)
N(1A)ꢁN(2A)
N(2A)ꢁC(12A)
N(3A)ꢁC(12A)
O(1A)ꢁC(12A)
2.07(2)
2.298(7)
2.311(6)
2.332(6)
2.59(1)
1.26(2)
1.39(2)
1.40(2)
1.35(3)
1.21(2)
Bond angles
C(1)ꢁPd(1)ꢁN(1)
C(1)ꢁPd(1)ꢁO(1)
N(1)ꢁPd(1)ꢁO(1)
C(1)ꢁPd(1)ꢁP(1)
N(1)ꢁPd(1)ꢁP(1)
O(1)ꢁPd(1)ꢁP(1)
C(8)ꢁO(1)ꢁPd(1)
C(7)ꢁN(1)ꢁN(2)
C(7)ꢁN(1)ꢁPd(1)
N(2)ꢁN(1)ꢁPd(1)
C(8)ꢁN(2)ꢁN(1)
C(2)ꢁC(1)ꢁC(6)
81.0(2)
157.6(2)
76.6(2)
C(5)ꢁPd(1)ꢁP(2)
C(5)ꢁPd(1)ꢁP(3)
C(5)ꢁPd(1)ꢁP(1)
P(2)ꢁPd(1)ꢁP(3)
P(2)ꢁPd(1)ꢁP(1)
P(3)ꢁPd(1)ꢁP(1)
C(5)ꢁPd(1)ꢁN(1)
P(2)ꢁPd(1)ꢁN(1)
P(3)ꢁPd(1)ꢁN(1)
P(1)ꢁPd(1)ꢁN(1)
C(11)ꢁN(1)ꢁN(2)
N(2)ꢁN(1)ꢁPd(1)
C(12)ꢁN(2)ꢁN(1)
O(1)ꢁC(12)ꢁN(3)
O(1)ꢁC(12)ꢁN(2)
N(3)ꢁC(12)ꢁN(2)
171.2(6)
96.0(5)
91.4(6)
84.3(2)
84.9(2)
154.9(2)
70.7(6)
117.1(4)
117.0(4)
88.0(4)
119(2)
C(5A)ꢁPd(2)ꢁP(2A)
C(5A)ꢁPd(2)ꢁP(3A)
C(5A)ꢁPd(2)ꢁP(1A)
P(2A)ꢁPd(2)ꢁP(1A)
P(2A)ꢁPd(2)ꢁP(1A)
P(1A)ꢁPd(2)ꢁP(3A)
C(5A)ꢁPd(2)ꢁN(1A)
P(2A)ꢁPd(2)ꢁN(1A)
P(3A)ꢁPd(2)ꢁN(1A)
P(1A)ꢁPd(2)ꢁN(1A)
C(11A)ꢁN(1A)ꢁN(2A)
N(2A)ꢁN(1A)ꢁPd(2)
C(12A)ꢁN(2A)ꢁN(1A)
O(1A)ꢁC(12A)ꢁN(3A)
O(1A)ꢁC(12A)ꢁN(2A)
N(3A)ꢁC(12A)ꢁN(2A)
170.4(6)
93.4(6)
94.8(6)
84.2(2)
84.2(2)
154.3(2)
72.8(6)
116.1(4)
87.3(4)
118.4(4)
119(2)
101.0(2)
177.1(1)
101.3(1)
111.6(4)
124.2(4)
120.1(3)
115.7(3)
114.7(4)
116.7(5)
130(1)
121(2)
125(2)
122(2)
132(1)
118(2)
123(2)
123(2)
112(2)
114(2)
,
(N(3)ꢁH(3c)···O(1a), 2.98(2) A, 179.4°; N(3A)ꢁH(3a)···
,
O(1), 2.93(2) A, 178.5°).
3. Experimental
CAUTION: perchlorate salts of metal complexes
with organic ligands are potentially explosive. Only
small amounts of these materials should be prepared
and handled with great caution.
3.1. Materials and instrumentation
Solvents were purified by standard methods [25].
Chemicals were reagent grade. The phosphines PPh3,
PMePh2, PEtPh2, PEt2PPh and (Ph2PCH2CH2)2PPh
(triphos) were purchased from Aldrich–Chemie. Com-
pounds a, b and c were prepared according to proce-
dures described elsewhere [12]. Microanalyses were
carried out at the Servicio de Ana´lisis Elemental at the
University of Santiago using a Carlo Erba Elemental
Analyser, Model 1108. NMR spectra were obtained as
CDCl3 or DMSO-d6 solutions and referenced to SiMe4
(1H) or 85% H3PO4 (31P-{1H}) and were recorded on
Bruker WM250, and AMX-300 spectrometers. All
chemical shifts were reported downfield from standards.
Fig. 3. Hydrogen bonding in 5b.

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
9
3.2.2. [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PMePh2)] (2a)
Yield 62% (Found: C, 51.6; H, 4.5; N, 7.9.
C23H25N3OClPdP requires C, 51.9; H, 4.7; N, 7.9%); IR
(wmax/cm−1) 1709 s (CꢀO), 1604 m (CꢀN), 290 w
(PdꢁCl).
3.2.3. [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PEtPh2)] (3a)
Yield 82% (Found: C, 53.1; H, 4.7; N, 7.9.
C24H27N3OClPdP requires C, 53.8; H, 5.0; N, 7.7%); IR
(wmax/cm−1) 1716 s (CꢀO), 1616 m (CꢀN), 290 w
(PdꢁCl).
3.2.4. [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PEt2Ph)] (4a)
Yield 79% (Found: C, 48.0; H, 5.5; N, 8.4.
C20H27N3OClPdP requires C, 48.2; H, 5.4; N, 8.4%); IR
(wmax/cm−1) 1713 s (CꢀO), 1608 m (CꢀN), 295 w
(PdꢁCl).
Fig. 4. Molecular structure of [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
{(Ph2PꢁCH2CH2)2PPh-P,P,P}][Cl] (10b).
3.2.5. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PPh3)] (1b)
Yield 75% (Found: C, 56.6; H, 4.7; N, 7.0.
C28H27N3OClPdP requires C, 56.6; H, 4.6; N, 7.1%); IR
(wmax/cm−1) 1691 s (CꢀO), 1626 m (sh) (CꢀN), 285 w
(PdꢁCl).
3.2.6. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PMePh2)] (2b)
Yield 67% (Found: C, 52.0; H, 4.6; N, 7.6.
C23H25N3OClPdP requires C, 51.9; H, 4.7; N, 7.9%); IR
(wmax/cm−1) 1690 s (CꢀO), 1629 m (CꢀN), 305 w
(PdꢁCl).
3.2.7. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PEtPh2)] (3b)
Yield 81% (Found: C, 53.6; H, 4.8; N, 7.5.
C24H27N3OClPdP requires C, 53.8; H, 5.0; N, 7.7%); IR
(wmax/cm−1) 1713 s (CꢀO), 1627 m (CꢀN), 297w
(PdꢁCl).
Fig. 5. Hydrogen bonding in 10b (phenyl ring atoms have been
omitted for clarity).
3.2. Preparations
3.2.8. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PEt2Ph)] (4b)
Yield 79% (Found: C, 47.9; H, 5.1; N, 8.4.
C20H27N3OClPdP requires C, 48.2; H, 5.4; N, 8.4%); IR
(wmax/cm−1) 1712 s(CꢀO), 1629 m (CꢀN), 280 w
(PdꢁCl).
3.2.1. Preparation of [Pd{4-MeC6H3C(Me)ꢀ
NN(H)C(ꢀO)NH2}(Cl)(PPh3)] (1a)
PPh3 (39 mg, 0.15 mmol) was added to a suspension
of a (50 mg, 0.15 mmol) in acetone (15 cm3). The
mixture was stirred for 4 h, the resulting white solid
filtered off and dried in air. Yield 60% (Found: C, 56.3;
H, 4.6; N, 7.3. C28H27N3OClPdP requires C, 56.6; H,
4.6; N, 7.1%); IR (wmax/cm−1) 1710 s (CꢀO), 1620 m
(CꢀN), 290 w (PdꢁCl).
Compounds 2a–4a, 1b–4b and 1c–4c were obtained
following a similar procedure as white or pale yellow
solids (1a, 1c and 3c).
3.2.9. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PPh3)] (1c)
Yield 69% (Found: C, 57.5; H, 4.5; N, 6.6.
C29H29N3OClPdP requires C, 57.2; H, 4.8; N, 6.9%); IR
(wmax/cm−1) 1710 s (CꢀO), 1614 m (sh) (CꢀN), 285 w
(PdꢁCl).

10
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
(wmax/cm−1) 1655 s (CꢀO), 1637 s (CꢀN); specific molar
conductivity, Lm=193 V−1 cm2 mol−1 (in acetonitrile).
3.2.10. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PMePh2)] (2c)
Yield 91% (Found: C, 52.4; H, 5.2; N, 7.6.
C24H27N3OClPdP requires C, 52.8; H, 5.0; N, 7.7%); IR
(wmax/cm−1) 1722 s (CꢀO), 1610 w (CꢀN), 292 w (PdꢁCl).
3.2.17. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(PPh3)]-
[ClO4] (5b)
Yield 81% (Found: C, 51.5; H, 4.1; N, 6.4.
C28H27N3O5ClPdP requires C, 51.1; H, 4.1; N, 6.4%); IR
(wmax/cm−1) 1649 m (CꢀO), 1626 m (sh) (CꢀN); specific
molar conductivity, Lm=169 V−1 cm2 mol−1 (in ace-
tonitrile).
3.2.11. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PEtPh2)] (3c)
Yield 79% (Found: C, 53.8; H, 4.9; N, 7.3. C25H29-
N3OClPdP requires C, 53.6; H, 5.2; N, 7.5%); IR (wmax
/
cm−1) 1713 s (CꢀO), 1612 m (sh) (CꢀN), 280 w (PdꢁCl).
3.2.18. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(PMePh2)-
][ClO4] (6b)
Yield 92% (Found: C, 46.4; H, 4.1; N, 6.8.
C23H25N3O5ClPdP requires C, 46.3; H, 4.2; N, 7.0%); IR
(wmax/cm−1) 1655 m (CꢀO), 1626 m (sh) (CꢀN); specific
molar conductivity, Lm=183 V−1 cm2 mol−1 (in ace-
tonitrile).
3.2.12. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(Cl)(PEt2Ph)] (4c)
Yield 80% (Found: C, 49.0; H, 5.4; N, 8.0.
C21H29N3OClPdP requires C, 49.2; H, 5.7; N, 8.2%); IR
(wmax/cm−1) 1720 s (CꢀO), 1618 m (CꢀN), 286 w (PdꢁCl).
3.2.13. Preparation of [Pd{4-MeC6H3C(Me)ꢀNN-
(H)C(ꢀO)NH2}(PPh3)][ClO4] (5a)
3.2.19. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(PEtPh2)]-
[ClO4] (7b)
Yield 72% (Found: C, 47.3; H, 4.5; N, 6.7.
C24H27N3O5ClPdP requires C, 47.2; H, 4.5; N, 6.9%); IR
(wmax/cm−1) 1655 s (CꢀO), 1626 m (sh) (CꢀN); specific
molar conductivity, Lm=170 V−1 cm2 mol−1 (in ace-
tonitrile).
A suspension of a (50 mg, 0.15 mmol) in acetone (15
cm3) was treated with silver perchlorate (32 mg) and
stirred for 2 h. The solution was filtered through Celite to
eliminate the AgCl precipitate. PPh3 (39 mg, 0.15 mmol)
was added to the filtrate and the solution stirred for 4 h,
the solvent removed and the product recrystallised from
dichloromethane–hexane to give the desired complex as a
white solid. Yield 81% (Found: C, 50.5; H, 4.2; N, 6.4.
C28H27N3O5ClPdP requires C, 51.1; H, 4.1; N, 6.4%); IR
(wmax/cm−1) 1655 s (CꢀO), 1640 s (sh) (CꢀN); specific
molar conductivity, Lm=193 V−1 cm2 mol−1 (in ace-
tonitrile).
3.2.20. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(PEt2Ph)]-
[ClO4] (8b)
Yield 65% (Found: C, 42.7; H, 4.7; N, 7.4.
C20H27N3O5ClPdP requires C, 42.7; H, 4.8; N, 7.5%); IR
(wmax/cm−1) 1651 s (CꢀO), 1637 s (CꢀN); specific molar
conductivity, Lmꢀ175 V−1 cm2 mol−1 (in acetonitrile).
Compounds 6a–8a, 5b–8b and 5c–8c were synthesised
following a similar procedure as white or yellow (7b, 5c
and 6c) solids.
3.2.21. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PPh3)][ClO4] (5c)
Yield 83% (Found: C, 51.6; H, 4.3; N, 6.1.
C29H29N3O5ClPdP requires C, 51.8; H, 4.3; N, 6.2%); IR
(wmax/cm−1) 1649 m (CꢀO), 1631 m (sh) (CꢀN); specific
molar conductivity, Lm=200 V−1 cm2 mol−1 (in ace-
tonitrile).
3.2.14. [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PMePh2)][ClO4] (6a)
Yield 92% (Found: C, 46.3; H, 4.2; N, 6.8. C23H25N3-
O5ClPdP requires C, 46.3; H, 4.2; N, 7.0%); IR (wmax
/
cm−1) 1656 m (CꢀO), 1634 s (sh) (CꢀN); specific molar
conductivity, Lm=213 V−1 cm2 mol−1 (in acetonitrile).
3.2.22. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PMePh2)][ClO4] (6c)
Yield 91% (Found: C, 46.9; H, 4.6; N, 6.7.
C24H27N3O5ClPdP requires C, 47.2; H, 4.5; N, 6.9%); IR
(wmax/cm−1) 1655 s (CꢀO), 1635 m (sh) (CꢀN); specific
molar conductivity, Lm=175 V−1 cm2 mol−1 (in ace-
tonitrile).
3.2.15. [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PEtPh2)][ClO4] (7a)
Yield 72% (Found: C, 47.4; H, 4.2; N, 6.6.
C24H27N3O5ClPdP requires C, 47.2; H, 4.5; N, 6.9%); IR
(wmax/cm−1) 1655 s (CꢀO), 1634 s (sh) (CꢀN); specific
molar conductivity, Lm=166 V−1 cm2 mol−1 (in ace-
tonitrile).
3.2.23. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PEtPh2)][ClO4] (7c)
3.2.16. [Pd{4-MeC6H3C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PEt2Ph)][ClO4] (8a)
Yield 65% (Found: C, 42.1; H, 4.9; N, 7.4.
Yield 68% (Found: C, 48.1; H, 4.7; N, 6.7.
C25H29N3O5ClPdP requires C, 47.2; H, 4.5; N, 6.9%); IR
(wmax/cm−1) 1651 s (CꢀO), 1632 m w(CꢀN); specific molar
conductivity, Lm=180 V−1 cm2 mol−1 (in acetonitrile).
C20H27N3O5ClPdP requires C, 42.7; H, 4.8; N, 7.5%); IR

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
11
3.2.24. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PEt2Ph)][ClO4] (8c)
molar conductivity, Lm=115 V−1 cm2 mol−1 (in
acetonitrile).
Yield 72% (Found: C, 44.0; H, 5.2; N, 7.1.
C21H29N3O5ClPdP requires C, 43.8; H, 5.1; N, 7.3%); IR
(wmax/cm−1) 1655 s (CꢀO), 1633 s (CꢀN); specific molar
conductivity, Lm=193 V−1 cm2 mol−1 (in acetonitrile).
3.2.30. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
{(Ph2PCH2CH2)2PPh-P,P,P}][Cl] (10c)
Yield 77% (Found: C, 61.0; H, 5.5; N, 4.6.
C45H47N3OClPdP3 requires C, 61.4; H, 5.5; N 4.8%); IR
(wmax/cm−1) 1685 s (CꢀO), 1587 m (CꢀN); specific
molar conductivity, Lm=112 V−1 cm2 mol−1 (in
acetonitrile).
3.2.25. Preparation of [Pd{4-MeC6H3C(Me)ꢀNN(H)-
C(ꢀO)NH2}(PEt2Ph)2(Cl)] (9a)
PEt2Ph (50 mg, 0.30 mmol) was added to a suspension
of a (50 mg, 0.15 mmol) in dichloromethane (15 cm3). The
solution was stirred for 4 h. The solvent was removed and
the product recrystallised from dichloromethane–hexane
to give the desired complex as a pale yellow solid. Yield
87% (Found: C, 54.6; H, 6.2; N, 6.3. C30H42N3OClPdP2
requires C, 54.3; H, 6.4; N, 6.3%); IR (wmax/cm−1) 1680
s (CꢀO), 1581 m (sh) (CꢀN), 300 w w(PdꢁCl).
Compounds 9b and 9c were synthesised following a
similar procedure as white solids.
3.3. Single-crystal X-ray diffraction analysis
3.3.1. Crystal structure determination of complex 5a
Three-dimensional, room temperature X-ray data
were collected in the q range 2.88–28.00° on a Siemens
Smart CCD diffractometer by the omega scan method.
Reflections were measured from a hemisphere of data
collected from frames each covering 0.3° in omega. Of
the 22784 reflections measured, all of which were
corrected from Lorentz and polarisation effects and for
absorption by semi-empirical methods based on
symmetry-equivalent and repeated reflections (minimum
and maximum transmission coefficients 0.7240 and
1.0000), 4256 independent reflections exceeded the
significance level ꢀFꢀ/|ꢀFꢀ\4.0. The structure was solved
by direct methods and refined by full-matrix least-
squares on F2. Hydrogen atoms were included in the
calculated positions and refined in riding mode.
Refinement converged at a final R=0.0607 (wR2=
0.1605, for all 7942 data, 338 parameters, mean and
maximum l/|=0.000, 0.001) with allowance for
thermal anisotropy of all non-hydrogen atoms. Mini-
mum and maximum final electron density −1.255 and
3.2.26. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}(PPh3)2(Cl)]
(9b)
Yield 91% (Found: C, 64.5; H, 4.6; N, 4.8.
C46H42N3OClPdP2 requires C, 64.5; H, 4.9; N, 4.9%);
IR (wmax/cm−1) 1691 s (CꢀO), 1628 m (sh) (CꢀN), 295
w w(PdꢁCl).
3.2.27. [Pd{3,4-Me2C6H2C(Me)ꢀNN(H)C(ꢀO)NH2}-
(PEt2Ph)2(Cl)] (9c)
Yield 86% (Found: C, 54.8; H, 6.6; N, 6.6.
C31H44N3OClPdP2 requires C, 54.9; H, 6.5; N, 6.2%);
IR (wmax/cm−1) 1691 s (CꢀO), 1583 m (CꢀN), 273 w
(PdꢁCl).
1.102 e A−3. The structure solution and refinement were
,
3.2.28. Preparation of [Pd{4-MeC6H3C(Me)ꢀ
NN(H)C(ꢀO)NH2}{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]
(10a)
carried out using the program package SHELX-97 [26].
To a suspension of 1a (40 mg, 0.12 mmol) in
dichloromethane (25 cm3) (Ph2PCH2CH2)2PPh (64 mg,
0.12 mmol) was added and the mixture stirred at room
temperature for 4 h. The solvent was removed and
the product recrystallised from dichloromethane–
hexane to give the desired complex as a white solid.
Yield 88% (Found: C, 60.8; H, 5.1; N, 4.8.
C44H45N3OClPdP3 requires C, 61.0; H, 5.2; N 4.8%); IR
(wmax/cm−1) 1692 s (CꢀO), 1587 m (CꢀN); specific
molar conductivity, Lm=104 V−1 cm2 mol−1 (in ace-
tonitrile).
3.3.2. Crystal structure determination of complex 10b
Three-dimensional, room temperature X-ray data
were collected in the range 3.5B2qB45° on a Nicolet
R3 diffractometer by the omega scan method. Of the
7804 reflections measured, all of which were corrected for
Lorentz and polarisation effects (but not for absorption),
4694 independent reflections exceeded the significance
level ꢀFꢀ/|(ꢀFꢀ)\4.0. The structure was solved by direct
methods and refined by blocked cascade least-squares
methods on F2. Hydrogen atoms were included in the
calculated positions and refined in riding mode.
Refinement converged at a final R=0.0721 (wR2=
0.1724, for all 6639 unique data; 686 parameters, mean
and maximum l/|=0.000, 0.002), with allowance
for the thermal anisotropy of all palladium, phosphorus,
nitrogen and whole occupancy chlorine atoms only.
Geometric constrains were used in all chloroform sol-
vent molecules. Minimum and maximum final elec-
Compounds 10b and 10c were obtained following a
similar procedure as white solids.
3.2.29. [Pd{C6H4C(Et)ꢀNN(H)C(ꢀO)NH2}-
{(Ph2PCH2CH2)2PPh-P,P,P}][Cl] (10b)
Yield 77% (Found: C, 61.2; H, 5.1; N, 4.8.
C44H45N3OClPdP3 requires C, 61.0; H, 5.2; N 4.8%); IR
(wmax/cm−1) 1691 s (CꢀO), 1585 m w(CꢀN); specific
tron density −0.456 and 0.660 e A−3. Complex scat-
,

12
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 598 (2000) 1–12
[12] J.M. Vila, T. Pereira, J.M. Ortigueira, M. Lo´pez-Torres, A.
Castin˜eiras, D. Lata, J.J. Ferna´ndez, A. Ferna´ndez, J.
Organomet. Chem. 556 (1998) 21.
tering factors were taken from the program package
SHELX-97 [26].
[13] J.M. Vila, M.T. Pereira, J.M. Ortigueira, M. Lo´pez-Torres, D.
Lata, M. Gran˜a, A. Sua´rez, J.J. Ferna´ndez, A. Ferna´ndez,
Unpublished results.
4. Supplementary material
[14] M. Nonoyama, Inorg. Chim. Acta 145 (1988) 53.
[15] J.M. Vila, M. Gayoso, A. Ferna´ndez, N.A. Bailey, H. Adams,
J. Organomet. Chem. 448 (1993) 233.
[16] J.M. Vila, M. Gayoso, M.T. Pereira, M. Lo´pez-Torres, J.J.
Ferna´ndez, A. Ferna´ndez, J.M. Ortigueira, Z. Anorg. Allg.
Chem. 623 (1997) 844.
Crystallographic data for the structural analysis has
been deposited with the Cambridge Crystallographic
Data Centre CCDC no. 132746 and 132747 for com-
pounds 5b and 10b, respectively.
[17] P.S. Pregosin, R.W. Kuntz, in: P. Diehl, E. Fluck, R. Kosfeld
(Eds.), 31P- and 13C-NMR of Transition Metal Phosphine Com-
plexes in NMR, Springer, Berlin, 1979, p. 52.
[18] L. Pauling, The Nature of the Chemical Bond, 3rd ed., Cornell
University, New York, 1960.
Acknowledgements
We thank the Xunta de Galicia (Spain) (Proyecto
XUGA20913B96) for financial support.
[19] S. Tollari, G. Palmisano, F. Demartin, M. Grassi, S. Magnaghi,
S. Cenini, J. Organomet. Chem. 488 (1995) 79.
[20] K.A. Abboud, S.P. Summers, G.J. Palenik, Acta Crystallogr.,
Sect. C 51 (1995) 1709.
[21] F. Cecconi, C.A. Ghilardi, S. Midollini, S. Moneti, A.
Orlandini, G. Scapacci, J. Chem. Soc. Dalton Trans. (1989)
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