Novel structures of cyclometallated complexes of palladium(II) derived from terdentate ligands. Crystal and molecular structure of [Pd{C6H4C(H)=NCH2CH2CH 2NMe2}(X)] (X = Cl, Br, I)

Article abstract of DOI:10.1016/S0022-328X(00)00567-2

Treatment of N-(2-chlorobenzylidene)-N,N-dimethyl-1,3-propanediamine (1) and N-(2-bromo-3,4-(MeO)₂-benzylidene)-N,N-dimethyl-1,3-propanediamine (20) with tris(dibenzylideneacetone)dipalladium(0) in toluene gave the mononuclear cyclometallated complexes [Pd{C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂}(Cl)] (2) and [Pd{3,4-(MeO)₂C₆H₂C(H)=NCH₂CH ₂CH₂NMe₂}(Br)] (21), respectively, via oxidative addition reaction with the ligand as a C,N,N terdentate ligand. Reaction of 2 with sodium bromide or iodide in an acetone-water mixture gave the cyclometallated analogues of 2, [Pd{C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂}(Br)] (3) and [Pd{C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂}(I)] (4), by halogen exchange. The X-ray crystal structures of 2, 3 and 4 were determined and discussed. Treatment of 2, 3, 4 and 21 with tertiary monophosphines in acetone gave the mononuclear cyclometallated complexes [Pd{C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂}(L)(X)] (6: L = PPh₃, X = Cl; 7: L = PPh₃, X = Br; 8: L = PPh₃, X = I; 9: L = PMePh₂, X = Cl; 10: L = PMe₂Ph, X = Cl) and [Pd{3,4-(MeO)₂C₆H₂C(H)=NCH₂CH ₂CH₂NMe₂}(L)(Br)] (22: L = PPh₃; 23: L = PMePh₂; 24: L = PMe₂Ph). A fluxional behaviour due to an uncoordinated CH₂CH₂CH₂NMe₂ could be determined by variable temperature NMR spectroscopy. Treatment of 2, 3 and 4 with silver trifluoromethanesulfonate followed by reaction with triphenylphosphine gave the mononuclear complex [Pd{C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂}(PPh₃)][F₃CSO₃] (11) where the Pd-NMe₂ bond was retained. Reaction of 2, 3 and 4 with ditertiary diphosphines in a cyclometallated complex-diphosphine 2:1 molar ratio gave the binuclear complexes [{Pd[C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂](X)}₂(μ-L-L)][L-L = PPh₂(CH₂)₄PPh₂(dppb) (13, X = Cl; 14, X = Br; 15, X = I; L-L = PPh₂(CH₂)₅PPh₂(dpppe): 16, X = Cl; 17, X = Br; 18, X = I) with palladium-NMe₂ bond cleavage. Treatment of 2, 3 and 4 with ditertiary diphosphines, in a cyclometallated complex-diphosphine 2:1, molar ratio and AgSO₃CF₃ gave the binuclear cyclometallated complexes [{Pd[C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂]}₂(μ-L-L)][F₃CSO ₃]₂ (11: L-L = PPh₂(CH₂)₄PPh₂(dppb), X = Cl; 12: L-L = PPh₂(CH₂)₅PPh₂ (dpppe), X = Cl). Reaction of 2 with the ditertiary diphosphine cis-dppe in a cyclometallated complex-diphosphine 1:1 molar ratio followed by treatment with sodium perchlorate gave the mononuclear cyclometallated complex [Pd{C₆H₄C(H)=NCH₂CH₂CH ₂NMe₂}(cis-PPh₂CH=CHPPh ₂-P,P)][ClO₄] (19).

Full text of DOI:10.1016/S0022-328X(00)00567-2

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 620 (2001) 8–19
Novel structures of cyclometallated complexes of palladium(II)
derived from terdentate ligands. Crystal and molecular structure of
[Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(X)] (X=Cl, Br, I)
Alberto Ferna´ndez a,*1, Patricia Ur´ıa a, Jesu´s J. Ferna´ndez a, Margarita Lo´pez-Torres a,
Antonio Sua´rez a, Digna Va´zquez-Garc´ıa a, Ma Teresa Pereira b, Jose´ M. Vila b,*2
a Departamento de Qu´ımica Fundamental, 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
Received 20 June 2000; accepted 22 July 2000
Abstract
Treatment of N-(2-chlorobenzylidene)-N,N-dimethyl-1,3-propanediamine (1) and N-(2-bromo-3,4-(MeO)2-benzylidene)-N,N-
dimethyl-1,3-propanediamine (20) with tris(dibenzylideneacetone)dipalladium(0) in toluene gave the mononuclear cyclometallated
complexes [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(Cl)] (2) and [Pd{3,4-(MeO)2C6H2C(H)ꢀNCH2CH2CH2NMe2}(Br)] (21), respec-
tively, via oxidative addition reaction with the ligand as a C,N,N terdentate ligand. Reaction of 2 with sodium bromide or iodide
in an acetone–water mixture gave the cyclometallated analogues of 2, [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(Br)] (3) and
[Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(I)] (4), by halogen exchange. The X-ray crystal structures of 2, 3 and 4 were determined
and discussed. Treatment of 2, 3, 4 and 21 with tertiary monophosphines in acetone gave the mononuclear cyclometallated
complexes [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(L)(X)] (6: L=PPh3, X=Cl; 7: L=PPh3, X=Br; 8: L=PPh3, X=I; 9:
L=PMePh2, X=Cl; 10: L=PMe2Ph, X=Cl) and [Pd{3,4-(MeO)2C6H2C(H)ꢀNCH2CH2CH2NMe2}(L)(Br)] (22: L=PPh3; 23:
L=PMePh2; 24: L=PMe2Ph). A fluxional behaviour due to an uncoordinated CH2CH2CH2NMe2 could be determined by
variable temperature NMR spectroscopy. Treatment of 2, 3 and 4 with silver trifluoromethanesulfonate followed by reaction with
triphenylphosphine gave the mononuclear complex [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(PPh3)][F3CSO3] (11) where the Pd–
NMe2 bond was retained. Reaction of 2, 3 and 4 with ditertiary diphosphines in a cyclometallated complex–diphosphine 2:1
molar ratio gave the binuclear complexes [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2](X)}2(m-L–L)][L–L=PPh2(CH2)4PPh2(dppb)
(13, X=Cl; 14, X=Br; 15, X=I; L–L=PPh2(CH2)5PPh2(dpppe): 16, X=Cl; 17, X=Br; 18, X=I) with palladium–NMe2
bond cleavage. Treatment of 2, 3 and 4 with ditertiary diphosphines, in a cyclometallated complex–diphosphine 2:1, molar ratio
and AgSO3CF3 gave the binuclear cyclometallated complexes [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2]}2(m-L–L)][F3CSO3]2 (11:
L–L=PPh2(CH2)4PPh2(dppb), X=Cl; 12: L–L=PPh2(CH2)5PPh2 (dpppe), X=Cl). Reaction of 2 with the ditertiary diphos-
phine cis-dppe in a cyclometallated complex–diphosphine 1:1 molar ratio followed by treatment with sodium perchlorate gave the
mononuclear cyclometallated complex [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(cis-PPh2CHꢀCHPPh2–P,P)][ClO4] (19). © 2001 El-
sevier Science B.V. All rights reserved.
Keywords: Palladium(II); Terdentate ligands; Cyclometallated
organometallic synthesis [6], in insertion reactions [7],
in the synthesis of new metal mesogenic compounds [8],
1. Introduction
in biologically active compounds [9] and in catalytic
Cyclometallated compounds have been widely stud-
materials [10]. By far, the most widely studied examples
ied over the last three decades [1–5]; such compounds
are five-membered palladacycles with nitrogen donors.
having found numerous applications in organic and
Generally, such compounds are prepared by reaction of
an organic ligand with either palladium acetate or a
tetrachloropalladate salt. Nevertheless, when the use of
palladium(II) salts as precursors did not yield the ex-
1 *Corresponding author.
2 *Corresponding author. Fax: +34-81-595012; e-mail: qide-
port@usc.es
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00567-2

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
9
2. Results and discussion
pected cyclometallated complexes, the synthesis via oxi-
dative addition of the halogenated ligands has proved
to be an alternative method [11,12].
For the convenience of the reader the compounds
and reactions are shown in Schemes 1 and 2. The
compounds described in this paper were characterised
by elemental analysis and by IR spectroscopy (data in
In previous work we have shown that potentially
terdentate lignads such as Schiff bases I [11,13], semi-
carbazones II [14,15] and thiosemicarbazones III [16,17]
undergo facile metallation with palladium(II), palla-
dium(0) and platinum(II) to give compounds with two
five-membered fused rings at the metal centre (Fig. 1).
When [C, N, O] and [C, N, N] derivatives were
treated with neutral ligands such as tertiary phosphines
cleavage of the nitrogen–metal or of the oxygen-metal
bonds occurred prior to ring-opening of the five-mem-
bered metallacycle upon continued reaction with the
corresponding phosphine. If the cyclometallated com-
pound was treated first with a silver(I) salt the chloride
ligand was removed as silver chloride and the vacant
coordination site was occupied by the phosphine.
In the present paper we report the intramolecular
oxidative addition of N-(2-chlorobenzylidene)-N,N-
dimethyl-1,3-propanediamine and of N-{2-bromo-3,4-
(MeO)2 - benzylidene} - N,N - dimethyl - 1,3 - propane-
diamine with tris(dibenzylideneacetone)dipalladium(0)
to give new cyclometallated complexes with two fused
rings at palladium, 2 and 21, respectively. The crystal
structures of 2 and of its bromine and iodine derivatives
are described. The reactivity of these complexes with
mono, and diphosphines in different reaction condi-
tions is also reported. One interesting feature is the
spectroscopic evidence of five-coordinated species in
solution by intramolecular nucleophilic attack of the
NMe2 nitrogen to the palladium atom.
1
Section 3) and by H- and 31P-{1H}- (see Table 1) and,
in part, 13C-{1H}-NMR spectroscopy (Section 3) and
FAB mass spectrometry.
The oxidative addition reaction of N-(2-chloroben-
zylidene)-N,N-dimethyl-1,3-propanediamine,
2-ClC6-
H4C(H)ꢀNCH2CH2CH2NMe2 (1), with tris(dibenzyli-
deneacetone)dipalladium(0) in toluene gave the cy-
clometallated complex [Pd{C6H4C(H)ꢀNCH2CH2-
CH2NMe2}(Cl)] (2), which was fully characterised. The
1H-NMR spectrum showed a singlet resonance at l
7.93 ppm assigned to the HCꢀN proton, shifted to
lower frequency due to coordination of the imine group
to the palladium atom via the lone pair of the nitrogen
atom [18]. The resonances at l 3.64, 2.59 and 1.91 ppm
were assigned to the CꢀNCH2, CH2NMe2 and
CH2CH2NMe2 protons, respectively. A singlet at l 2.67
ppm was assigned to the NMe2 protons and was shifted
to higher frequency consequent upon coordination of
the amine nitrogen atom to palladium [11].
The 13C-{1H} spectrum showed resonances at l 175.0
(CꢀN), l 155.8 (C6) and l 145.4 (C1) downfield shifted
from those for the free ligand in accordance with
formation of the cyclometallated ring [11,19]. The sig-
nal assigned to the NMe2 group was also shifted to
higher frequency showing coordination of the amino
nitrogen atom. Formation of the coordinated ring was
confirmed by the separation of the two methylene reso-
nances CꢀNCH2···CH2NMe2 (ca. 5 ppm) as compared
to the uncoordinated ligand.
The IR spectrum showed the w(CꢀN) band at 1610
cm−1 shifted to lower wavenumbers in accordance with
coordination of the palladium atom to the CꢀN moiety
[20].
The FAB mass spectrum showed signals assigned to
[M]+ and [M–Cl]+, as well as signals due to recombi-
nation peaks [2M+Cl]+ and [2M–Cl]+; all had rea-
sonable isotopic patterns.
Fig. 1.
Thus, the palladium atom is bonded to a phenyl
carbon atom, the imine and amine nitrogen atoms and
a chlorine atom, giving a compound with two fused
rings at the metal center, a five-membered ring (the
metallacycle) and a six-memebered ring (the coordina-
tion cycle).
Reaction of 3,4-(MeO)2-2-Br-C6H2(H)ꢀNCH2CH2-
CH2NMe2
(20)
with
tris(dibenzylideneacetone)-
dipalladium(0) yielded the cyclometallated complex
[Pd{3,4 - (MeO)2C6H2C(H)ꢀNCH2CH2CH2NMe2}(Br)]
(21), via an oxidative addition reaction, which was fully
Scheme 1. (i) [Pd2(dba)3] (toluene); (ii) NaX (acetone–water).

10
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
Scheme 2. (i) cis-dppe, NaClO4 (acetone, 1:1 molar ratio); (ii) AgCF3SO3, PPh3 (acetone); (iii) AgCF3SO3, dppb or dpppe (acetone, 2:1 molar
ratio); (iv) dppb or dpppe (acetone, 2:1 molar ratio); (v) PR3 (acetone).
characterised (see Table 1 and Section 3). The NMR
and IR data are similar to those for compound 2
confirming metallation of the organic ligand and coor-
dination of both amino and imino nitrogen atoms to
palladium.
halide extraction as silver halide. The complex was fully
characterised (see Section 3 and Table 1). The 1H-NMR
spectrum showed a doublet of doublets at l 6.25 ppm
assigned to H5. The resonance at l 8.40 ppm was
assigned to the imine proton. Both signals showed
coupling to the 31P nucleus of the phosphine ligand
(JHP=5.8, 7.8 Hz for H5 and Hi, respectively), indi-
cating the relative cis disposition of the phosphine and
the metallated phenyl carbon atom [11,21–24]. The
NMe2 resonance appeared at l 2.17 ppm shifted to
lower frequency when compared with compound 2,
suggesting shielding of the methyl protons by the phos-
phine phenyl rings [12]. Coordination of the amine
nitrogen atom to palladium was confirmed by the low-
field shift of the NMe2 resonance in their 13C-NMR
spectrum, assigned at l 48.6 ppm (l 49.4 for 2) and by
the separation of the two methylene resonances
CꢀNCH2···CH2NMe2 (6.5 ppm) in the 13C-{1H}-NMR.
The 31P-{1H}-NMR spectrum showed a singlet reso-
nance at l 40.5 ppm in accordance with a phosphorus-
to-nitrogen trans geometry [12,23]. Thus, the palladium
atom is coordinated to both the imine and amine
nitrogen atoms and the phosphine ligand occupies the
When 2 was treated with aqueous sodium bromide or
sodium iodide solutions the complexes [Pd{C6H4C(H)ꢀ
NCH2CH2CH2NMe2}(Br)] (3) and [Pd{C6H4C(H)ꢀ
NCH2CH2CH2NMe2}(I)] (4) were obtained as pure air-
stable solids which were fully characterised (see Table 1
and Section 3). NMR spectra for the complexes were
similar to those for 2 with the most noticeable differ-
ence in the low-field shift of the H5 resonance (l 7.97
ppm, l 8.28 ppm and l 8.77 ppm for 2, 3 and 4,
respectively) suggesting some interaction between the
halogen and the hydrogen atoms. All these observa-
tions were confirmed by the X-ray determination of the
molecular structures for 2, 3 and 4.
Treatment of the cyclometallated complexes 2, 3 or 4
with silver trifluormethanesulfonate followed by reac-
tion with triphenylphosphine in acetone yielded the
cyclometallated complex [Pd{C6H4C(H)ꢀNCH2CH2-
CH2NMe2}(PPh3)][CF3SO3] (see Scheme 2) (5) after

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
11
Table 1
Table 1 (Continued)
31P a- and 1H b-NMR data c,d
Com- 31P Aromatic
pound
Others
Com- 31P Aromatic
pound
Others
m
12
32.1s
8.30[d, 1H, HCꢀN, 7.3 g]
3.86[br, 2H, CH2
i
1
2
3
4
5
6
7
7.91[d, 1H, H2, 7.3 f]
8.61[s, 1H, HCꢀN]
6.93[t, 1H, H3, 7.3 f]
]
i
k
7.20[m, 3H, H3, H4, H5]
3.58[m, 2H, CH2
2.26[m, 2H, CH2
1.77[m, 2H, CH2
2.14[s, 3H, Me]
]
]
6.65[dt, 1H, H4, 7.3 f, 1.5 h] 2.65[br, 2H, CH2
]
6.43[dd, 1H, H5, 5.8 g]
2.03[br, 2H, CH2
2.16[s, 3H, Me]
]
k
j
j
]
13
14
15
16
17
18
19
34.3s 7.22[dd, 1H, H2, 7.3 f, 1.5 h] 8.08[s, 1H, HCꢀN, 7.8 n]
i
7.97[dd, 1H, H5, 7.3 f, 1.5 h] 7.93[s, 1H, HCꢀN]
6.89[dt, 1H, H3, 7.3 f, 1.0 h] 3.96[m, 2H, CH2
]
7.04[m, 2H, H3, H4]
3.64[m, 2H, CH2
]
6.57[dt, 1H, H4, 7.3 f]
6.40[d, 1H, H5, 5.9 n]
2.36[m, 2H, CH2
2.05[m, 2H, CH2
2.23[s, 3H, Me]
]
i
k
7.19[dd, 1H, H2, 7.3 f, 1.9 h] 2.59[m, 2H, CH2
1.91[m, 2H, CH2
]
]
k
j
j
]
2.67[s, 3H, Me]
m
33.2s
8.12[s, 1H, HCꢀN]
i
8.28[dd, 1H, H5, 7.1 f, 1.9 h] 8.04[s, 1H, HCꢀN]
6.90[t, 1H, H3, 7.3 f]
6.57[t, 1H, H4, 7.3 f]
6.37[d, 1H, H5]
4.08[m, 2H, CH2
2.43[m, 2H, CH2
2.09[m, 2H, CH2
2.28[s, 3H, Me]
]
i
k
7.12[m, 3H, H2, H3, H4]
3.68[m, 2H, CH2
2.62[m, 2H, CH2
1.95[m, 2H, CH2
2.73[s, 3H, Me]
]
]
k
j
]
]
j
]
35.6s 7.22[dd, 1H, H2, 7.3 f, 1.5 h] 8.15[s, 1H, HCꢀN]
8.77[dd, 1H, H5, 7.0 f, 1.9 h] 8.11[s, 1H, HCꢀN]
6.89[t, 1H, H3, 7.3 f, 1.0 h] 4.26[m, 2H, CH2
]
i
6.97[m, 2H, H3, H4]
3.66[m, 2H, CH2
]
6.58[dt, 1H, H4, 7.3 f]
6.31[d, 1H, H5]
2.38[m, 2H, CH2
2.05[m, 2H, CH2
2.24[s, 3H, Me]
]
i
k
7.23[dd, 1H, H2, 7.0 f, 1.9 h] 2.55[m, 2H, CH2
1.97[m, 2H, CH2
]
]
k
j
j
]
2.80[s, 3H, Me]
34.4s 7.22[dd, 1H, H2, 7.3 f, 1.5 h] 8.08[s, 1H, HCꢀN]
40.5s 7.34[dd, 1H, H2, 7.3 f, 1.5 h] 8.40[d, 1H, HCꢀN, 7.8 g]
6.87[dt, 1H, H3, 7.3 f, 1.0 h] 3.94[m, 2H, CH2
]
i
6.87[t, 1H, H3, 7.3 f,]
6.40[dt, 1H, H4, 7.3 f]
6.25[dd, 1H, H5, 5.8 g]
3.92[br, 2H, CH2
2.75[br, 2H, CH2
2.16[m, 5H, Me, CH2
2.17[s, 3H, Me]
]
6.55[dt, 1H, H4, 7.3 f]
6.40[d, 1H, H5]
2.37[m, 2H, CH2
2.04[m, 2H, CH2
2.23[s, 3H, Me]
]
i
k
k
j
]
]
j
]
30.4s 7.22[dd, 1H, H2, 7.3 f, 1.5 h] 8.10[s, 1H, HCꢀN]
41.7s 7.26[dd, 1H, H2, 7.6 f, 1.5 h] 8.14[s, 1H, HCꢀN]
6.88[t, 1H, H3, 7.3 f]
6.56[dt, 1H, H4, 7.3 f]
6.37[d, 1H, H5]
4.06[m, 2H, CH2
2.36[m, 2H, CH2
2.04[m, 2H, CH2
2.22[s, 3H, Me]
]
i
6.89[t, 1H, H3, 7.6 f, 1.0 h] 3.96[m, 2H, CH2
]
]
i
k
6.51[dt, 1H, H4, 7.6 f]
6.39[d, 1H, H5]
2.34[m, 2H, CH2
2.04[m, 2H, CH2
2.21[s, 3H, Me]
]
]
k
j
j
]
35.1s 7.21[dd, 1H, H2, 7.3 f, 1.9 h] 8.15[s, 1H, HCꢀN]
6.89[t, 1H, H3, 7.3 f]
6.57[dt, 1H, H4, 7.3 f]
6.31[d, 1H, H5]
4.25[m, 2H, CH2
2.37[m, 2H, CH2
2.04[m, 2H, CH2
2.23[s, 3H, Me]
]
i
42.6s
8.17[s, 1H, HCꢀN]
4.11[m, 2H, CH2
6.91[t, 1H, H3, 7.3 f]
]
]
i
k
6.53[dt, 1H, H4, 7.3 f, 1.5 h] 2.37[m, 2H, CH2
]
]
k
j
6.38[d, 1H, H5]
2.07[m, 2H, CH2
2.23[s, 3H, Me]
]
j
m
62.6d
8.36[d, 1H, HCꢀN, 8.3 g]
40.6s 7.25[dd, 1H, H2, 7.3 f, 1.5 h] 8.20[s, 1H, HCꢀN]
51.2d 7.21[dt, 1H, H3, 7.8 f, 1.4 h] 3.61[br, 2H, CH2
]
i
8
6.90[t, 1H, H3, 7.6 f]
6.53[br, 1H, H4]
6.39[br, 1H, H5]
4.32[br, 2H, CH2
2.37[br, 2H, CH2
2.23[s, 3H, Me]
]
J(PP) 6.93[m, 2H, H4, H5]
1.95[m, 2H, CH2 ]
i
k
k
]
10.5
j
1.25[m, 2H, CH2
2.05[s, 3H, Me]
]
9 l
24.2s
11.2s
8.10[s, 1H, HCꢀN, 7.8 g]
m
6.90[dt, 1H, H3, 7.3 f, 1.0 h] 3.97[m, 2H, CH2
6.59[dt, 1H, H4, 7.3 f, 1.5 h] 2.37[m, 2H, CH2
]
20
21
7.50[s, 1H, H2]
6.97[s, 1H, H5]
8.50[s, 1H, HCꢀN]
3.90[s, 3H, OMe]
3.87[s, 3H, OMe]
3.63[m, 2H, CH2
2.46[m, 2H, CH2
1.90[m, 2H, CH2
2.31[s, 3H, Me]
i
k
]
6.40[d, 1H, H5, 6.3 n]
2.07[m, 2H, CH2
2.23[s, 3H, Me]
]
j
i
]
k
]
10 l
8.07[d, 1H, HCꢀN, 7.8 g]
m
j
]
6.95[dt, 1H, H3, 7.3 f, 1.0 h] 3.94[m, 2H, CH2
6.76[dt, 1H, H4, 7.3 f, 1.5 h] 2.35[m, 2H, CH2
]
i
k
]
6.51[dd, 1H, H5, 6.3 g]
2.08[m, 2H, CH2
2.23[s, 3H, Me]
]
7.90[s, 1H, H5]
6.79[s, 1H, H2]
7.92[s, 1H, HCꢀN]
3.95[s, 3H, OMe]
j
3.80[s, 3H, OMe]
11
32.0s 7.32[dd, 1H, H2, 7.3 f, 1.5 h] 8.30[d, 1H, HCꢀN, 7.8 g]
i
3.63[m, 2H, CH2
2.57[m, 2H, CH2
1.95[m, 2H, CH2
2.72[s, 3H, Me]
]
]
]
i
6.90[t, 1H, H3, 7.3 f,]
6.63[dt, 1H, H4, 7.3 f]
6.39[dd, 1H, H5, 5.7 g]
3.87[br, 2H, CH2
2.04[br, 2H, CH2
2.16[s, 3H, Me]
]
]
k
j
j

12
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
Table 1 (Continued)
Treatment of 2, 3, 4 and 21 with tertiary phosphines
gave the mononuclear cyclometallated complexes
[Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(L)(X)] (6: L=
PPh3, X=Cl; 7: L=PPh3, X=Br; 8: L=PPh3, X=I;
9: L=PMePh2, X=Cl; 10: L=PMe2Ph, X=Cl) and
[Pd{3,4 - (MeO)2C6H2C(H)ꢀNCH2CH2CH2NMe2}(L)-
(Br)]: (22: L=PPh3; 23: L=PMePh2; 24: L=PMe2Ph)
which were fully characterised (see Section 3 and Table
Com- 31P Aromatic
pound
Others
22
42.0s 6.84[s, 1H, H2]
8.06[s, 1H, HCꢀN]
5.93[s, 1H, H5]
3.77[s, 3H, OMe]
2.83[s, 3H, OMe o]
i
4.03[m, 2H, CH2
2.35[m, 2H, CH2
2.04[m, 2H, CH2
2.22[s, 3H, Me]
]
]
]
k
1
j
1). The NMe2 resonance in the H-NMR spectra ap-
peared at ca. l 2.2 ppm (l 2.14 and 2.31 for 1 and 20,
respectively) suggesting that the NMe2 group was not
coordinated. In the 13C-{1H}-NMR spectra of complex
6 the resonance corresponding to the NMe2 carbon
appeared at l 45.3 ppm (l 45.4 ppm for the non-coor-
dinated ligand) and the separation of the two methylene
resonances CꢀNCH2···CH2NMe2 (0.6 ppm) confirmed
Pd–NMe2 bond cleavage. The IR spectra showed
w(CꢀN) bands in the range 1620–1630 cm−1, shifted to
lower wavenumbers as compared with the non-coordi-
nated ligands, consistent with palladium coordination
to the imine nitrogen atom. Reaction of these mononu-
clear complexes with silver trifluoromethanesulfonate
gave a silver halide precipitate showing the presence of
a halide ligand coordinated to the palladium. This has
been confirmed by the microanalytical data.
23 l
24.8s 6.88[s, 1H, H2]
6.04[s, 1H, H5]
8.13[s, 1H, HCꢀN]
3.77[s, 3H, OMe]
3.01[s, 3H, OMe o]
i
3.89[m, 2H, CH2
2.37[m, 2H, CH2
2.00[m, 2H, CH2
2.24[s, 3H, Me]
]
]
]
k
j
24 l
12.1s 6.77[s, 1H, H2]
7.93[d, 1H, HCꢀN, 7.8 g]
5.85[d, 1H, H5, 6.84 g]
3.77[s, 3H, OMe]
3.02[s, 3H, OMe o]
i
3.97[br, 2H, CH2
2.35[m, 2H, CH2
2.00[br, 2H, CH2
2.23[s, 3H, Me]
]
]
k
j
]
a In CDCl3 unless otherwise stated. Measured at 80.9 MHz (ca.
920°C); chemical shifts (l) in ppm (90.1) to high frequency of 85%
H3PO4.
When the cyclometallated complexes 2, 3 and 4 were
treated with the diphosphines dppb and dpppe in a
complex/phosphine 2:1 molar ratio the binuclear cy-
b In CDCl3 unless otherwise stated. Measured at 200 MHz (ca.
920°C); chemical shifts (l) in ppm (90.01) to high frequency of
SiMe4.
c Coupling constants in Hz.
clometallated
complexes
[{Pd[C6H4C(H)ꢀNCH2-
d s, singlet; d, doublet; dd, doublet of doublets; t, triplet; dt doublet
CH2CH2NMe2](X)}2(m-PPh2(CH2)nPPh2)] (13: n=4,
X=Cl; 14: n=4, X=Br; 15: n=4, X=I; 16: n=5,
X=Cl; 17: n=5, X=Br; 18: n=5, X=I) were ob-
of triplets; m, multiplet; br, broad.
f 3J(HH).
g 4J(PH).
1
tained (see Section 3 and Table 1). The H- and 13C-
h 4J(HH).
{1H}-NMR of the complexes again showed the
resonance corresponding to the NMe2 groups close to
their position in the free ligand, as well as a small
separation between the methylene signals in the 13C-
{1H}-NMR spectra indicating the cleavage of the palla-
dium–Namine bond. The IR spectra showed the shift
towards lower wavenumbers of the w(CꢀN) band as a
consequence of imine nitrogen coordination to the pal-
ladium atom. The 31P-{1H}-NMR spectra showed a
singlet resonance as a consequence of the centrosym-
metric nature of the binuclear complexes.
i HCꢀNCH2.
j HCꢀNCH2CH2.
k CH2NMe2.
l l(phosphine methyl protons), 2.20d (9),1.88d (10), 2.21d (23),
1.86d (24); 2J(CH3P)=10.2(9), 10.7 (10), 11.7(23), 10.2 (24).
m Occluded by methylene or aromatic (phosphine) resonances.
n 4J(PH), taken from a low temperature 1H-NMR spectrum (243
K).
o C(4)–MeO.
fourth co-ordination site which was left vacant after
removal of the chlorine atom.
In the 1H-NMR spectra of the mononuclear com-
plexes 22, 23 and 24 the C(4)–OMe resonance was
shifted towards lower frequency by ca. 0.8 ppm as
compared to the parent cyclometallated complex, due
to the shielding effects of the phosphine phenyl rings, in
accordance with a N–Pd–P trans geometry [13,14,25].
In related cyclometallated palladium(II) Schiff base
complexes with a tertiary phosphine ligand trans to the
CꢀN nitrogen atom the HCꢀN and H5 resonances
show coupling to the 31P nucleus, except in the cases
when the Pd–N was cleaved. This seems to be the case
for complexes 10 and 24 (with PMe2Ph). However, the
Reaction of the cyclometallated complexes 2, 3 and 4
with silver trifluoromethanesulfonate followed by treat-
ment with the ditertiary diphosphines dppb and dpppe
in a complex–diphosphine 2:1 molar ratio gave the
dinuclear cyclometallated complexes [{Pd[C6H4C(H)ꢀ
NCH2CH2CH2NMe2]}2 (m-PPh2(CH2)nPPh2)] [F3CSO3]2
1
(11, n=4; 12, n=5). The IR, H- and 13C-{1H}-NMR
data are in agreement with tri-coordination of the
organic ligand. The 31P-{1H}-NMR spectra showed a
singlet resonance at ca. l 32 ppm, in each case, suggest-
ing that the compounds are centrosymmetric as we
have shown before in related species [14,16].

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
13
1H-NMR spectra of complexes 6–9 and 22, 23 showed
no coupling of the HCꢀN and H5 resonances to the 31P
nucleus. This coupling is also absent in the spectra of
compounds 13–18; this would lead us to believe the
phosphine is trans to the metallated carbon atom. A
similar behaviour has been observed by us in related
cyclometallated complexes where in the starting mate-
rial there are two fused rings at the metal centre and the
coordination site of the phosphine ligand is dependent
on the nature of its substituents [11]; the less basic
phosphines (PPh3, PMePh2, –CH2PPh2) seem to prefer
a C–Pd–P trans geometry, whereas the more basic
phosphines (PMe2Ph) favor a N–Pd–P trans arrange-
ment. This reactivity is different to that observed in
dinuclear halide-bridged palladium(II) cyclometallated
complexes where it is known that bridge-splitting reac-
tions with tertiary phosphines invariably give mononu-
clear species with the incoming phosphine adopting a
N–Pd–P trans geometry [24]. Nevertheless, the shift of
the C(4)–OMe resonance mentioned above controverts
this and an improved argument is needed. Therefore, in
an attempt to throw some light on this subject we
carried out further experiments, and thus in an NMR
tube excess PMe2Ph was added to a chloroform solu-
tion of compound 21 (21–PMe2Ph 1:1.5 molar ratio).
showed two singlets at l 12.7 and l −8.7 ppm, which
were assigned to the coordinated phosphine and to the
free phosphine, respectively. The PMe2Ph resonance
1
appeared as a broad singlet in the H-NMR spectrum
at 298 K, which collapsed to a doublet at 253 K.
1
Furthermore, the H-NMR spectrum of compound 9 at
298 K showed doublet and singlet signals for the H5
and HCꢀN protons, respectively, whereas at 273 K a
triplet and a doublet were observed, respectively; the
same was found in the 1H-NMR spectrum of com-
pound 13. No further changes were observed at lower
temperatures. The 31P-{1H}-NMR spectra showed only
one singlet in each case for the phosphorus resonance.
In view that nucleophilic substitutions reactions in
square-planar palladium(II) usually proceeds through a
five-coordinated intermediate [26], we believe that a
possible equilibrium at room temperature between four-
and five-coordinated species could be responsible for
the behaviour of these complexes, as is depicted in
Scheme 3.
Once interaction between the palladium atom and
the phosphine ligand has been established, the complex
goes through
a five-coordinate intermediate that
evolves either to a square-planar geometry with the
phosphine ligand trans to nitrogen (c), favoured by the
more basic phosphines, or trans to carbon (d), preferred
by the less basic ones. The (c)l(d) equilibrium,
through (b), holds at room temperature; the key step
being interaction of the amine nitrogen with the palla-
1
At 298 K the H-NMR spectrum showed two singlets
assigned to the HCꢀN and H5 resonances; the 31P-
{1H}-NMR spectrum showed a slightly broad singlet.
At 253 K the HCꢀN and H5 resonances appeared as
sharp doublets and the 31P-{1H}-NMR spectrum
Table 2
Crystal and structure refinement data
2
3
4
Formula
Mr
C12H17N2ClPd
331.13
C12H17N2BrPd
375.58
C12H17N2IPd
422.58
Temperature (K)
293(2)
293(2)
293(2)
,
Wavelength (A)
0.71073
Orthorhombic
P212121
0.71073
Orthorhombic
Pccn
0.71073
Monoclinic
P21/c
Crystal system
Space group
Unit cell dimensions
,
a (A)
10.093(1)
10.376(1)
12.666(1)
16.104(3)
18.718(1)
8.800(1)
8.994(1)
16.669(1)
9.583(1)
100.359(1)
1413.3(1)
4
,
b (A)
,
c (A)
i (°)
V (A )
3
,
1326.4(1)
4
1.576
2652.5(8)
8
4.388
Z
v (mm−1
)
3.475
Crystal size (mm)
2qmax (°)
0.60×0.50×0.40
66.3
0.50×0.40×0.35
56.6
0.35×0.20×0.15
59.9
Reflections collected
Reflections unique
Transmissions
12564
13805
7657
4950 (Rint=0.03)
0.57, 0.45
150
0.0295
0.0787
0.555
0.0273(12)
−0.02(4)
3295 (Rint=0.05)
0.31, 0.22
150
0.0397
0.0942
3442 (Rint=0.02)
0.62, 0.38
150
0.0288
0.0830
No. of parameters
R [F, I\2|(I)]
wR [F2, all data]
−3
,
Max z (e A
)
1.248
0.0068(3)
0.984
0.0068(4)
Extinction coefficient
Absolute structure parameter

14
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
Scheme 3.
dium atom, which is not possible in complexes with
monodentate Schiff base ligands. In complexes 9 and 13
cooling the sample yields form (c), as confirmed by the
NMR spectra, whereas in complex 24 excess phosphine
at room temperature gives the complex with two mutu-
ally trans phosphine ligands which seems to be in
equilibrium with form (c); in this case the more basic
phosphine, PMe2Ph, occupies the fifth coordination
position, displacing the NMe2 group in the reaction
intermediate.
Fig. 2. Molecular structure of complex [Pd{C6H4C(H)ꢀNCH2-
CH2CH2NMe2}(Cl)] (2). Hydrogen atoms have been omitted for
clarity.
Reaction of 2 with the ditertiary diphosphine cis-
dppe in a cyclometallated complex–diphosphine 1:1
molar ratio followed by treatment with sodium perchlo-
rate gave the mononuclear cyclometallated complex
[Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(cis - PPh2CHꢀ
CHPPh2–P,P)][ClO4] (19) which was fully characterised
(see Section 3 and Table 1). The 31P-{1H}-NMR spec-
trum showed two doublets for the two inequivalent
phosphorus nuclei. The resonance at lower frequency
was assigned to the phosphorus nucleus trans to the
phenyl carbon atom in accordance with the higher trans
influence of the latter with respect to the CꢀN nitrogen
atom [27]. The HCꢀN resonance was only coupled to
the 31P nucleus trans to nitrogen. This was confirmed
by selective decoupling experiments on the 31P atoms.
Fig. 3. Molecular structure of complex [Pd{C6H4C(H)ꢀNCH2CH2-
CH2NMe2}(Br)] (3). Hydrogen atoms have been omitted for
clarity.
1
In the H-NMR the l (Me2) resonance was shifted to
lower frequency as a consequence of the Pd–NMe2
bond cleavage.
2.1. Crystal structures of [Pd{C6H4C(H)ꢀ
NCH2CH2CH2NMe2}(X)]; XꢀCl (2), Br (3), I (4)
Suitable crystals of the title compounds were grown
by slowly evaporating a chloroform solution. The
molecular structures which are illustrated in the Figs.
2–4 consist of discrete molecules separated by van der
Waals distances.
In all cases the palladium is bonded in a slightly
distorted square-planar geometry to the C(1) carbon
atom of the phenyl ring, the iminic N(1) and amine
N(2) nitrogen atoms and to the corresponding halogen
atom. The angles between adjacent atoms in the coordi-
nation sphere of palladium are close to the expected
value of 90° with the most noticeable distortions corre-
sponding to the C(1)–Pd(1)–N(1) angles of 81.08(12)°
Fig. 4. Molecular structure of complex [Pd{C6H4C(H)ꢀNCH2CH2-
CH2NMe2}(I)] (4). Hydrogen atoms have been omitted for clarity.
and 80.92(16)° for 2 and 3, respectively, and the N(2)–
Pd(1)–I(1) angle of 99.88(10)° for 4 (Table 3). The sum
of the angles about palladium is approximately 360° in
all cases.
,
The Pd–N(1) (2.029(3), 2.028(4) and 2.071(3) A for
2, 3 and 4, respectively) and Pd–N(2) (2.203(3),

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
15
Table 3
Selected bond distances (A) and angles (°) for complexes 2, 3 and 4
,
2
3
4
Pd(1)–C(1)
Pd(1)–N(1)
Pd(1)–N(2)
Pd(1)–Cl(1)
C(1)–C(6)
C(6)–C(7)
N(1)–C(7)
Cl(1)–H(2)
1.991(3)
2.029(3)
2.203(3)
2.3071(8)
1.398(4)
1.449(5)
1.290(4)
2.82(4)
Pd(1)–C(1)
Pd(1)–N(1)
Pd(1)–N(2)
Pd(1)–Br(1)
C(1)–C(6)
C(6)–C(7)
N(1)–C(7)
Br(1)–H(2)
1.985(4)
2.028(4)
2.208(4)
2.4219(7)
1.400(6)
1.441(6)
1.263(6)
2.72(5)
Pd(1)–C(1)
Pd(1)–N(1)
Pd(1)–N(2)
Pd(1)–I(1)
C(1)–C(6)
C(6)–C(7)
N(1)–C(7)
I(1)–H(2)
1.990(3)
2.071(3)
2.243(3)
2.6556(4)
1.387(5)
1.532(6)
1.228(5)
2.86(4)
C(1)–Pd(1)–N(1)
C(1)–Pd(1)–N(2)
N(1)–Pd(1)–N(2)
C(1)–Pd(1)–Cl(1)
N(2)–Pd(1)–Cl(1)
C(6)–C(1)–Pd(1)
C(1)–C(6)–C(7)
N(1)–C(7)–C(6)
C(7)–N(1)–Pd(1)
C(8)–N(1)–Pd(1)
81.08(12)
173.39(10)
94.94(11)
92.29(9)
91.86(8)
113.1(2)
114.0(3)
117.3(3)
114.3(2)
125.7(2)
C(1)–Pd(1)–N(1)
C(1)–Pd(1)–N(2)
N(1)–Pd(1)–N(2)
C(1)–Pd(1)–Br(1)
N(2)–Pd(1)–Br(1)
C(6)–C(1)–Pd(1)
C(1)–C(6)–C(7)
N(1)–C(7)–C(6)
C(7)–N(1)–Pd(1)
C(8)–N(1)–Pd(1)
80.92(16)
174.67(16)
94.79(17)
92.38(12)
91.69(13)
112.4(3)
113.9(4)
117.9(4)
114.1(3)
126.1(4)
C(1)–Pd(1)–N(1)
C(1)–Pd(1)–N(2)
N(1)–Pd(1)–N(2)
C(1)–Pd(1)–I(1)
N(2)–Pd(1)–I(1)
C(6)–C(1)–Pd(1)
C(1)–C(6)–C(7)
N(1)–C(7)–C(6)
C(7)–N(1)–Pd(1)
C(8)–N(1)–Pd(1)
87.71(13)
172.12(13)
86.29(13)
86.02(10)
99.88(10)
105.2(3)
118.9(3)
119.7(3)
108.1(3)
131.0(3)
,
2.208(4) and 2.243(3) A for 2, 3 and 4, respectively)
bond distances are similar to others reported for related
compounds [14,16,28]. The Pd–N(2) bond length,
longer than Pd–N(1) distance, shows the stronger trans
influence of the donor ligand.
between these atoms. This observation is in agreement
with the low-field shift observed for the resonance
corresponding to this proton in the 1H-NMR spectra of
the complexes.
The Pd–C(1) bond distances of 1.991(3), 1.985(4)
,
and 1.990(3) A (for 2, 3 and 4, respectively) are some-
3. Experimental
what shorter than the values predicted from their cova-
lent radii [29] but similar to values found earlier [14,16].
The Pd–Cl(1) and Pd–Br(1) bond distances (2.3071(8),
Safety note: CAUTION! Perchlorate salts of metal
complexes with organic ligands are potentially explo-
sive. Only small amounts of these materials should be
prepared and handled with great caution.
,
2.4219(7) A for 2 and 3, respectively) are in accordance
with the values found earlier in similar cyclometallated
compounds [30–34]. Nevertheless the Pd–I(1) bond
,
length of 2.6556 (4) A is somewhat longer than the
3.1. General procedures
values found in related complexes with I trans to N
[28]. We think this is due to the important steric
repulsion between the large iodine atom and the –
NMe2 methyl groups. This is confirmed by the enlarged
I(1)–Pd–N(2) bond angle of 99.88(10)° (as compared
to the Cl(1)–Pd–N(2) and Br(1)–Pd–N(2) angles of
91.86(8) and 91.69(13)° for 2 and 3, respectively.
The geometry around the palladium atom [Pd, C(1),
N(1), C(2), X(1)] is planar (r.m.s.=0.0567, 0.0208 and
Solvents were purified by standard methods [35].
Chemicals were reagent grade. The phosphines PPh3,
PMePh2, PMe2Ph, cis-Ph2P(H)CꢀC(H)PPh2, (cis-dppe)
Ph2P(CH2)4PPh2 (dppb) and Ph2P(CH2)5PPh2 (dpppe)
were purchased from Aldrich-Chemie. Microanalyses
were carried out using a Carlo Erba Elemental Analy-
ser, Model 1108. IR spectra were recorded as Nujol
mulls or polythene discs on a Perkin–Elmer 1330 spec-
trometer. NMR spectra were obtained as CDCl3 solu-
tions and referenced to SiMe4 (1H, 13C-{1H}) or 85%
H3PO4 (31P-{1H}) and were recorded on a Bruker AC-
2005 spectrometer. All chemical shifts were reported
downfield from standards. The FAB mass spectra were
recorded using a Fisons Quatro mass spectrometer with
a Cs ion gun; 3-nitrobenzyl alcohol was used as the
matrix.
,
0.0380 A for 2, 3 and 4, respectively; plane 1). The
metallated ring [Pd, C(1), C(6), C(7), N(1)] is also
,
planar (r.m.s.=0.0167, 0.0429 and 0.0320 A for 2, 3
and 4, respectively; plane 2). Angles between planes are
as follows: plane 1/plane 2=4.3°, 6.2° and 5.6° for 2, 3
and 4. As expected, the coordination ring (Pd, N(1),
C(8), C(9), C(10), N(2)) shows large deviations from
planarity with C(8) and C(10) lying above the least-
square plane and C(9) below.
The synthesis of 2-ClC6H4(H)ꢀNCH2CH2CH2NMe2
(1) and 3,4-(MeO)2-6-BrC6H2(H)ꢀNCH2CH2CH2NMe2
(20) were performed by heating a chloroform solution
The distance between the aromatic hydrogen H2 and
,
the halogen atom (Cl(1)–H(2), 2.82(4) A; Br(1)–H(2),
,
,
2.72(5) A; I(1)–H(2), 2.86(4) A) shows some interaction

16
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
of the appropriate quantities of N,N-dimethyl-1,3-
propanediamine and 2-chlorobenzaldehyde or 6-
bromoveratraldehyde, respectively, in a Dean–Stark
apparatus under reflux. IR (wmax (cm−1)), (CꢀN) 1640s
(1), 1650 s (20). 13C-{1H}-NMR for ligand 1 (50.28
MHz, CDCl3): l 157.9 (CꢀN); l 134.9 (C1); l 133.2
(C6); l 131.1, 129.7, 128.8, 126.9 (C2, C3, C4, C5); l
(CꢀNCH2CH2CH2NMe2); l 50.4 (NMe2). FAB (m/z):
[MH]+ 377; [M–Br]+ 295; [M–Br, M]+ 670.
Compound 4 was obtained following a similar proce-
dure but treating 2 with NaI, as a yellow solid.
3.2.4. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(I)] (4)
Yield: 73%. Found: C, 34.0; H, 4.2; N, 6.3.
C12H17N2IPd requires C, 34.1; H, 4.1; N, 6.6%. IR (wmax
(cm−1)), (CꢀN) 1620 w. 13C-{1H}-NMR (50.28 MHz,
CDCl3): l 175.5 (CꢀN); l 153.0 (C6); l146.2 (C1);
l153.0 (C5); l 131.0, 127.7, 123.9 (C2, C3, C4); l 64.1,
57.7 (CꢀNCH2CH2CH2NMe2); l 26.3 (CꢀNCH2CH2-
CH2NMe2); l 52.3 (NMe2). FAB (m/z): [M]+ 423.
59.6,
57.3
(CꢀNCH2CH2CH2NMe2):
l
28.7
(CꢀNCH2CH2CH2NMe2); l 45.4 (NMe2). FAB (m/z)
(1): [M]+ 225.
3.2. Syntheses
3.2.1. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(Cl)] (2)
A
pressure tube containing 2-ClC6H4C(H)ꢀ
3.2.5. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(PPh3)]-
[CF3SO3] (5)
NCH2CH2CH2NMe2 (1) (0.172 g, 0.770 mmol), tris-
(dibenzylideneacetone)dipalladium(0) (0.400 g, 0.350
mmol) and 20 cm3 of dry toluene was sealed under
argon. The dark-red solution was heated at 80°C for 1
h. After this time the dark solution turned to bright
yellow and a black palladium precipitate appeared.
After cooling to room temperature (r.t.) the solution
was filtered through Celite. The solvent was removed
under vacuum to give a yellow oil which was treated
with ca. 10 cm3 of diethylether and stirred for 5 min;
the resulting yellow solid filtered off, washed with ether
and dried in vacuo. Yield: 67%. Elemental analysis
(EA): Found: C,43.5; H, 5.1; N, 8.5. C12H17N2ClPd
requires C, 43.5; H, 5.2; N, 8.5%. IR (wmax (cm−1)),
(CꢀN) 1610s. 13C-{1H}-NMR (50.28 MHz, CDCl3): l
175.0 (CꢀN); l 155.8 (C6); l145.4 (C1); l136.7 (C5); l
A suspension of 2 (0.030 g, 0.091mmol) in acetone
(15 cm3) was treated with silver trifluoromethane-
sulfonate (0.026 g, 0.100 mmol) and stirred for 2 h. The
resulting solution was filtered through Celite to
eliminate the AgCl precipitate. PPh3 (0.024, 0.091
mmol) was added to the filtrate, the solution stirred for
another 4 h and the solvent removed to give a yellow
solid which was recrystallized from dichloro-
methane–hexane. Yield: 80%. E.A.: Found: C, 52.6; H,
4.4; N, 3.9. C31H32F3N2O3PSPd requires C, 52.7; H,
4.6; N, 4.0%. IR (wmax (cm−1)), (CꢀN) 1639 m.
13C-{1H}-NMR (50.28 MHz, CDCl3): l 178.0 (CꢀN); l
153.4 (C6); l 146.8 (C1); l 138.8d J(PC) 12.0 (C5); l
129.9, 129.3, 125.2 (C2, C3, C4);
l 62.0, 55.5
(CꢀNCH2CH2CH2NMe2); 25.3 (CꢀNCH2CH2-
l
130.1, 127.0, 124.2 (C2, C3, C4);
l
63.2, 58.0
CH2NMe2); l 48.6 (NMe2). P-Phenyl: l 130.7d, J(PC)
39.7 (Ci); l 135.4d, J(PC) 12.1 (Co); l 129.1d, J(PC)
10.7 (Cm); l 132.0 (Cp).
(CꢀNCH2CH2CH2NMe2);
l
26.4 (CꢀNCH2CH2-
CH2NMe2); l 49.4 (NMe2). FAB (m/z): [M]+ 330;
[M–Cl]+ 295; [M–Cl, M]+ 627; [2M+Cl]+ 699.
Compound 21 was obtained similarly as an orange
solid.
Compound 5 was also obtained following a similar
procedure but using compounds 3 or 4 as starting
materials.
3.2.2. [Pd{3,4-(MeO)2C6H2C(H)ꢀNCH2CH2CH2-
NMe2}(Br)] (21)
3.2.6. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(PPh3)(Cl)]
(6)
Yield: 64%. EA: Found: C,38.4; H, 4.8; N, 6.3.
C14H21N2BrO2Pd requires C, 38.6; H, 4.9; N, 6.4%. IR
(wmax (cm−1)) (CꢀN) 1620s.
PPh3 (0.024 g, 0.091 mmol) was added to a
suspension of 2 (0.030 g, 0.091 mmol) in acetone (15
cm3). The mixture was stirred for 4 h, the solvent
removed and the resulting yellow oil recrystallized from
dichloromehane–hexane to give a pale yellow solid.
Yield: 60%. EA: Found: C, 60.7; H, 5.2; N, 4.4.
C30H32N2ClPdP requires C, 60.7; H, 5.4; N, 4.7%. IR
(wmax (cm−1)), (CꢀN) 1626 s. 13C-{1H}-NMR (50.28
MHz, CDCl3): l 175.6 (CꢀN); l 157.9 (C6); l 148.1
(C1); l 138.1 (C5); l 129.6, 128.6, 123.9 (C2, C3, C4);
3.2.3. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(Br)] (3)
An aqueous solution of NaBr (ca. 10−2 M) was
added dropwise to a solution of 2 (0.030 g, 0.091 mmol)
in 15 cm3 of acetone. The product separated
immediately as a yellow solid. After stirring for 1 h, the
solid was filtered off and recrystallized from dichloro-
methane–hexane. Yield: 77%. EA: Found: C, 38.2; H,
4.6; N, 7.3. C12H17N2BrPd requires C, 38.4; H, 4.6; N,
7.4%. IR (wmax (cm−1)), (CꢀN) 1610 s. 13C-{1H}-NMR
(50.28 MHz, CDCl3): l 175.2 (CꢀN); l 154.5 (C6); l
145.7 (C1); l 139.7 (C5); l 130.5, 127.3, 124.2 (C2, C3,
C4); l 63.6, 57.8 (CꢀNCH2CH2CH2NMe2); l 26.3
l
56.9, 56.4 (CꢀNCH2CH2CH2NMe2);
l
28.3
(CꢀNCH2CH2CH2NMe2); l 45.3 (NMe2). P-Phenyl: l
131.6d, J(PC) 42.6 (Ci); l 135.1d, J(PC) 12.8 (Co); l
128.0d, J(PC) 10.7 (Cm); l 130.4d (Cp) J(PC) 1.4.
Compounds 7 and 8 were synthesized following a
similar procedure as yellow solids.

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
17
3.2.7. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(PPh3)(Br)]
(7)
Yield: 73%. EA: Found: C, 55.3; H, 5.3; N, 4.0.
C30H32N2BrPdP requires C, 56.5; H, 5.1; N, 4.4%. IR
(wmax (cm−1)), (CꢀN) 1620 s.
fonate (0.026 g, 0.100 mmol) and stirred for 2 h. The
solution was filtered through Celite to eliminate the
AgCl precipitate. PPh2(CH2)4PPh2 (0.019, 0.045 mmol)
was added to the filtrate, the solution stirred for 4 h
and the solvent removed to give a yellow oil which was
recrystallized from chloroform–hexane to give a yellow
solid. Yield: 60%. EA: Found: C, 49.5; H, 4.6; N, 4.4.
C54H62F6N4O6P2S2Pd2 requires C, 49.3; H, 4.7; N,
4.2%. IR (wmax (cm−1)), (CꢀN) 1638 s. 13C-{1H}-NMR
(50.28 MHz, CDCl3): l 176.8 (CꢀN); l 153.1 (C6); l
147.2 (C1); l 136.8d J(PC) 10.7 (C5); l 130.5, 129.9,
125.4 (C2, C3, C4); l 69.6, 54.6 (CꢀNCH2CH2-
CH2NMe2); l 26.0 (CꢀNCH2CH2CH2NMe2); l 48.2
(NMe2). P-Phenyl: l 131.3d, J(PC) 49.7 (Ci); l 133.8d,
J(PC) 11.4 (Co); l 129.3d, J(PC) 10.8 (Cm); l 131.8
(Cp). CH2-Phosphine: 28.5, 27.5.
3.2.8. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}(PPh3)(I)]
(8)
Yield: 60%. EA: Found: C, 52.3; H, 4.6; N, 4.5.
C30H32N2IPdP requires C, 52.6; H, 4.7; N, 4.1%. IR
(wmax (cm−1)), (CꢀN) 1625 s.
3.2.9. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}-
(PMePh2)(Cl)] (9)
PMePh2 (0.018 g, 0.090 mmol) was added to a sus-
pension of 2 (0.030 g, 0.091 mmol) in acetone (15 cm3).
The mixture was stirred for 4 h and the solvent re-
moved to give a yellow oil which could not be recrystal-
lized. Yield: 90%. EA: Found: C, 55.0; H, 5.3; N, 5.0.
C25H30N2ClPdP requires C, 56.5; H, 5.7; N, 5.3%. IR
(wmax (cm−1)), (CꢀN) 1630 m.
Compound 11 was also obtained following a sim-
ilar procedure but using 3 or 4 as starting mater-
ials.
Compound 12 was obtained following a similar pro-
cedure as a yellow solid.
Compound 10 was obtained following a similar pro-
cedure as a yellow oil.
3.2.15. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2]}2-
(v-PPh2(CH2)5PPh2)][CF3SO3]2 (12)
3.2.10. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}-
(PMe2Ph)(Cl)] (10)
Yield: 60%. EA: Found: C, 49.5; H, 4.8; N, 4.6.
C55H64F6N4O6P2S2Pd2 requires C, 49.6; H, 4.8; N,
4.2%. IR (wmax (cm−1)), (CꢀN) 1636 s. 13C-{1H}-NMR
(50.28 MHz, CDCl3): l 176.8 (CꢀN); l 155.7 (C6); l
147.3 (C1); l 137.0 (C5); l 130.7, 130.0, 125.3 (C2, C3,
C4); l 69.2, 54.6 (CꢀNCH2CH2CH2NMe2); l 28.2
(CꢀNCH2CH2CH2NMe2); l 49.4 (NMe2). P-Phenyl: l
133.8d, J(PC) 11.4 (Co); l 129.2d, J(PC) 9.9 (Cm); l
131.8 (Cp). CH2-Phosphine: 29.2, 27.8, 21.6.
Yield: 90%. EA: Found: C, 49.0; H, 5.8; N, 6.5.
C20H28N2ClPdP requires C, 51.2; H, 6.0; N, 6.0%. IR
(wmax (cm−1)), (CꢀN) 1625 s.
Compounds 22 and 24 were obtained following a
similar procedure to that for 6 as yellow solids.
3.2.11. [Pd{3,4-(MeO)2C6H2C(H)ꢀNCH2CH2CH2-
NMe2}(PPh3)(Br)] (22)
Yield: 90%. EA: Found: C, 55.0; H, 5.0; N, 4.4.
C32H36N2BrO2PdP requires C, 55.1; H, 5.2; N, 4.1%. IR
(wmax (cm−1)), (CꢀN) 1625 m.
3.2.16. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2](Cl)}2(v-
PPh2(CH2)4PPh2)] (13)
3.2.12. [Pd{3,4-(MeO)2C6H2C(H)ꢀNCH2CH2-
CH2NMe2}(PMe2Ph)(Br)] (24)
Yield: 63%. EA: Found: C, 45.3; H, 5.5; N, 4.8.
C22H32N2BrO2PdP requires C, 46.0; H, 5.6; N, 4.9%. IR
(wmax (cm−1)), (CꢀN) 1630 m.
PPh2(CH2)4PPh2 (0.019 g, 0.045 mmol) was added to
a suspension of 2 (0.030 g, 0.091 mmol) in acetone (15
cm3). The mixture was stirred for 4 h, the resulting
yellow precipitate was filtered off and dried in air.
Yield: 57%. EA: Found: C, 57.7; H, 5.8; N, 5.2.
C52H62Cl2N4P2Pd2 requires C, 57.4; H, 5.7; N, 5.1%. IR
(wmax (cm−1)), (CꢀN) 1625s. 13C-{1H}-NMR (50.28
MHz, CDCl3): l 175.0 (CꢀN); l 157.8 (C6); l 148.0
(C1); l 137.5 (C5); l 129.9, 128.6, 123.9 (C2, C3, C4);
l 56.4 (CꢀNCH2CH2CH2NMe2); l 28.2 (CꢀNCH2-
CH2CH2NMe2); l 45.3 (NMe2). P-Phenyl: l 128.1d,
J(PC) 41.2 (Ci); l 134.0d, J(PC) 11.4 (Co); l 128.4d,
J(PC) 9.9 (Cm); l 130.7 (Cp). CH2-Phosphine: 29.6,
26.4 J(PC) 33.4, 9.9.
Compound 23 was obtained following a similar pro-
cedure to that for 9 as a yellow oil.
3.2.13. [Pd{3,4-(MeO)2C6H2C(H)ꢀNCH2CH2-
CH2NMe2}(PMePh2)(Br)] (23)
Yield: 90%. EA: Found: C, 47.0; H, 5.0; N, 4.1.
C27H34N2BrO2PdP requires C, 51.0; H, 5.4; N, 4.4%. IR
(wmax (cm−1)), (CꢀN) 1620 w.
3.2.14. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2]}2-
(v-PPh2(CH2)4PPh2)][CF3SO3]2 (11)
Compounds 14, 15, 16, 17 and 18 were synthesized
following a similar procedure as yellow solids.
A suspension of 2 (0.030 g, 0.091 mmol) in acetone
(15 cm3) was treated with silver trifluoromethanesul-

18
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 620 (2001) 8–19
3.2.17. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2](Br)}2-
(v-PPh2(CH2)4PPh2)] (14)
Yield: 55%. EA: Found: C, 53.2; H, 5.2; N, 4.6
C52H62Br2N4P2Pd2 requires C, 53.0; H, 5.3; N, 4.7%. IR
(wmax (cm−1)), (CꢀN) 1630s.
sphere of data collected of frames each covering 0.3° in
omega. Of the reflections measured, all of which were
corrected from Lorentz and polarisation effects and for
absorption by semi-empirical methods based on sym-
metry-equivalent and repeated reflections, 4419 for 2,
2394 for 3 and 2917 for 4 independent reflections
exceeded the significance level ꢀFꢀ/|ꢀFꢀ\4.0 (Table 2).
The structure was solved by direct methods and refined
by full matrix least squares on F2 with allowance for
thermal anisotropy of all non-hydrogen atoms. Hydro-
gen atoms were included in calculated positions and
refined in riding mode (except H2 which was located in
a difference Fourier map and refined isotropically). The
structure solution and refinement were carried out using
the program package SHELX-97 [36].
3.2.18. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2](I)}2-
(v-PPh2(CH2)4PPh2)] (15)
Yield: 51%. EA: Found: C, 49.3; H, 4.9; N, 4.5.
C52H62I2N4P2Pd2 requires C, 49.1; H, 4.9; N, 4.4%. IR
(wmax (cm−1)), (CꢀN) 1620w.
3.2.19. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2](Cl)}2-
(v-PPh2(CH2)5PPh2)] (16)
Yield: 60%. EA: Found: C, 57.4; H, 5.6; N, 4.6.
C53H64Cl2N4P2Pd2 requires C, 57.7; H, 5.8; N, 5.1%. IR
(nmax (cm−1)), (CꢀN) 1625s. 13C-{1H}-NMR (50.28
MHz, CDCl3): l 175.0 (CꢀN); l 157.8 (C6); l 148.0
(C1); l 137.6 (C5); l 129.9, 128.7, 124.0 (C2, C3, C4);
4. Supplementary material
l
56.5, 56.4 (CꢀNCH2CH2CH2NMe2);
l
29.5
Crystallographic data for the structures reported in
this paper have been deposited with the Cambridge
Crystallographic Data Centre, CCDC no. 144952, for
compound 2, CCDC no. 144951 for compound 3, and
CCDC no. 144950 for compound 4. Copies of this
information may be obtained free of charge from the
Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK (fax: +44-1223-336033; e-mail: deposit@
ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
(CꢀNCH2CH2CH2NMe2); l 45.3 (NMe2). P-Phenyl: l
128.1d, J(PC) 51.8 (Ci); l 134.0d, J(PC) 11.7 (Co); l
128.4d, J(PC) 9.9 (Cm); l 130.7 (Cp). CH2-Phosphine:
31.9, 28.9, 24.0.
3.2.20. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2](Br)}2-
(v-PPh2(CH2)5PPh2)] (17)
Yield: 75%. EA: Found: C, 53.2; H, 5.3; N, 4.4.
C53H64Br2N4P2Pd2 requires C, 53.4; H, 5.4; N, 4.7%. IR
(wmax (cm−1)), (CꢀN) 1620s.
Acknowledgements
3.2.21. [{Pd[C6H4C(H)ꢀNCH2CH2CH2NMe2](I)}2-
(v-PPh2(CH2)5PPh2)] (18)
Yield: 45%. EA: Found: C, 49.3; H, 5.0; N, 4.3.
C53H64I2N4P2Pd2 requires C, 49.5; H, 5.0; N, 4.4%. IR
(wmax (cm−1)), (CꢀN) 1630s.
We would like to thank the Xunta de Galicia
(XUGA20913B96) and the University of La Corun˜a for
financial support.
3.2.22. [Pd{C6H4C(H)ꢀNCH2CH2CH2NMe2}-
(cis-PPh2CHꢀCHPPh2-P,P)][ClO4] (19)
References
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a suspension of 2 (0.030 g, 0.091 mmol) in acetone (20
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57.7; H, 5.0; N, 3.5%. IR (wmax (cm−1)), (CꢀN) 1618 m.
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