Polynuclear cyclometallated palladium (II) complexes derived from potentially hexadentate Schiff base ligands. Crystal structures of [(Cl)Pd{Me2NCH2CH2N=(H)C}C6H 2{C(H)=NCH2CH2NMe2}-Pd(Cl)] and [{(Ph2PCH2CH2)2PPh-P,P,P}Pd{Me 2NCH2-CH2

Article abstract of DOI:10.1016/S0022-328X(00)00417-4

The oxidative addition reaction of 1,4-(C=N(H)CH₂CH₂Me₂)₂-2,5-Cl ₂C₆H₂ with tris(dibenzylideneacetone)dipalladium(0) in benzene gave the doubly cyclometallated compound [(Cl)Pd{Me₂NCH₂CH₂N=(H)C}C₆H ₂{C(H)=NCH₂CH₂NMe₂}Pd(Cl)] (1) with each palladium atom C,N,N′bonded to the ligand. Treatment of 1 with thallium acetylacetonate gave the dinuclear cyclometallated complex 2 with two chelating acetylacetonate ligands. Reaction of 1 with tertiary monophosphines in a 1-phosphine 1:2 molar ratio gave dinuclear cyclometallated complexes 3-7, in which the palladium-NMe₂ bond has been broken, whereas treatment of 1 with silver perchlorate, followed by reaction with PPh₃ in a 1-phosphine 1:2 molar ratio gave cyclometallated complex 4 where the ligand remains C,N,N′ bonded and the chloride ligand has been substituted by triphenylphosphine. Treatment of 1 with tertiary diphosphines leads to dinuclear compounds 8, 10 and 11, whilst previous treatment of 1 with silver perchlorate followed by the diphosphine 1,4-bis(diphenylphosphino)butane (dppb) in a 1-diphosphine 1:1 molar ratio yielded the tetranuclear complex 9. Reaction of 1 with the tertiary triphosphine bis(2-diphenylphosphinoethyl)phenylphosphine in 1:2 molar ratio gave the complex [{(Ph₂PCH₂CH₂)₂PPh-P,P,P}Pd(Me ₂NCH₂CH₂N=(H)C}-C₆H ₂{C(H)=NCH₂CH₂NMe₂}Pd{(Ph ₂PCH₂CH₂)₂PPh-P,P,P}][Cl] ₂ (12) in which both palladium atoms are pentacoordinated. The crystal structures of 1 and 12 are described.

Full text of DOI:10.1016/S0022-328X(00)00417-4

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 612 (2000) 85–95
Polynuclear cyclometallated palladium (II) complexes derived from
potentially hexadentate Schiff base ligands. Crystal structures of
[(Cl)Pd{Me2NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}-
Pd(Cl)] and [{(Ph2PCH2CH2)2PPh-P,P,P}Pd{Me2NCH2-
CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}-
Pd{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]2
Alberto Ferna´ndez a, Jesu´s J. Ferna´ndez a, Margarita Lo´pez-Torres a, Antonio Sua´rez a,
Juan M. Ortigueira b, Jose´ M. Vila b,*, Harry Adams c
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
c Department of Chemistry, Uni6ersity of Sheffield, Sheffield S3 7HF, UK
Received 27 April 2000; received in revised form 5 July 2000
Abstract
The oxidative addition reaction of 1,4-(CꢀN(H)CH2CH2Me2)2-2,5-Cl2C6H2 with tris(dibenzylideneacetone)dipalladium(0) in
benzene gave the doubly cyclometallated compound [(Cl)Pd{Me2NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd(Cl)] (1)
with each palladium atom C,N,N% bonded to the ligand. Treatment of 1 with thallium acetylacetonate gave the dinuclear
cyclometallated complex 2 with two chelating acetylacetonate ligands. Reaction of 1 with tertiary monophosphines in a
1–phosphine 1:2 molar ratio gave dinuclear cyclometallated complexes 3–7, in which the palladiumꢁNMe2 bond has been broken,
whereas treatment of 1 with silver perchlorate, followed by reaction with PPh3 in a 1–phosphine 1:2 molar ratio gave
cyclometallated complex 4 where the ligand remains C,N,N% bonded and the chloride ligand has been substituted by
triphenylphosphine. Treatment of 1 with tertiary diphosphines leads to dinuclear compounds 8, 10 and 11, whilst previous
treatment of 1 with silver perchlorate followed by the diphosphine 1,4-bis(diphenylphosphino)butane (dppb) in a 1–diphosphine
1:1 molar ratio yielded the tetranuclear complex 9. Reaction of 1 with the tertiary triphosphine bis(2-diphenylphosphi-
noethyl)phenylphosphine in 1:2 molar ratio gave the complex [{(Ph2PCH2CH2)2PPh-P,P,P}Pd{Me2NCH2CH2Nꢀ(H)C}-
C6H2{C(H)ꢀNCH2CH2NMe2}Pd{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]2 (12) in which both palladium atoms are pentacoordinated.
The crystal structures of 1 and 12 are described. © 2000 Elsevier Science B.V. All rights reserved.
Keywords: Palladium; Cyclometallation; Schiff base; Dinuclear complexes; Oxidative addition; Phosphine complexes
1. Introduction
mesogenic compounds [8], biologically active com-
pounds [9] and in catalytic materials [10]. By far, the
most widely studied examples are five-membered pal-
ladacycles with nitrogen donors. Generally, such com-
pounds are prepared by reaction of an organic ligand
with either palladium acetate or a tetrachloropalladate
salt. Where the synthesis using palladium(II) salts as
starting materials does not yield the expected cy-
clometallated complexes, synthesis via oxidative addi-
tion to halogenated ligands has shown to be an
adequate method to achieve metallation [11,12].
Cyclometallated compounds have been much studied
over the last three decades [1–5], showing numerous
applications in organic and organometallic synthesis [6],
in insertion reactions [7], in the synthesis of new metal
* Corresponding author. Fax: +34-981-595012.
E-mail address: qideport@usc.es (J.M. Vila).
0022-328X/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00417-4

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A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
2. Results and discussion
In previous work we have shown that potentially
terdentate ligands 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 mononuclear com-
pounds with two five-membered fused rings at the
metal centre (Fig. 1).
For the convenience of the reader the compounds
and reactions are shown in Schemes 1 and 2. The
compounds described in this paper were characterized
by elemental analyses, IR spectroscopy (data in Section
1
3), H-, 31P-{1H}- (see Table 1) and, in part, by 13C-
{1H}-NMR (Section 3).
When [C, N, O] and [C, N, N] derivatives are treated
with neutral ligands such as tertiary phosphines cleav-
age of the oxygen–metal or of the nitrogen–metal
bonds occurs prior to ring-opening of the five-mem-
bered metallacycle upon continued reaction with the
corresponding phosphine. If the cyclometallated com-
pound has been treated previously with a silver(I) salt,
the chloride ligand is removed as silver chloride and the
vacant coordination site is occupied by the phosphine.
Doubly cyclometallated complexes, containing two
metallated phenyl rings are frequent [18] but relatively
few are known with two metallated sites on the same
phenyl ring [19], or where each metal atom coordinates
to the ligand through three donor atoms [20]. Less
common are those in which both metal atoms coordi-
nate to the same phenyl ring [13,21].
As part of our interest in the study of complexes
derived from potentially terdentate ligands, in the
present paper we report the synthesis via oxidative
addition reaction of a new doubly cyclometallated
palladium(II) complex derived from the hexadentate
ligand 1,4-(CꢀN(H)CH2CH2Me2)2-2,5-Cl2C6H2. The X-
ray crystal structure of this complex is reported, this
being one of the few examples in which a cyclometal-
lated complex derived from a doubly terdentate ligand
is described [22]. We also give an account of its reactiv-
ity with tertiary mono and diphosphines. Recently, we
have become interested in the reactivity of cyclometal-
lated complexes with terdentate phosphines in order to
obtain unusual coordination numbers and modification
of the geometry at the metal centre. The reaction of the
cyclometallated halide-bridged complexes with bis(2-
diphenylphosphinoethyl)phenylphosphine (triphos) has
proved to be a novel route in promoting pentacoordi-
nation in palladium(II) [23]. Following our studies in
this area we report the results of the reaction between 1
and the terdentate ligand. The crystal structure of this
complex is also presented.
The oxidative addition reaction of 1,4-(CꢀN(H)-
CH2CH2Me2)2-2,5-Cl2C6H2 with tris(dibenzylideneace-
tone)dipalladium(0) in benzene gave the dicyclo-
metallated
compound
[(Cl)Pd{Me2NCH2CH2Nꢀ
(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd(Cl)] (1), which
was fully characterized. The 1H-NMR spectrum
showed well-defined ‘virtual triplet’ patterns at l 3.89
and l 2.93 ppm for the CꢀNCH2 and CH2NMe2 pro-
tons, respectively, with Nꢀ11.8 Hz; a singlet at l 2.30
ppm was assigned to the NMe2 methyl protons, which
was shifted to higher frequency as compared to the free
ligand showing palladium coordination to the amine
nitrogen atom. The singlet resonance at l 7.94 ppm was
assigned to the HCꢀN protons shifted to lower fre-
quency confirming palladium–nitrogen coordination
[24]. The 13C-{1H} spectrum showed resonances at l
173.4 ppm (CꢀN) and l 151.4 (C2, C5) ppm downfield
shifted (related to the free ligand) as a consequence of
cyclometallated ring formation [25,11]. The signal as-
signed to the NMe2 carbon atoms was also shifted to
higher frequency upon coordination to the amino nitro-
gen atom. The palladium–nitrogen bond formation
was confirmed by the separation of the two methylene
resonances (ca. 10 ppm; cf. 0 ppm for the non-coordi-
nated ligand) [11].
The IR spectrum showed a band at 1600 cm−1
shifted to lower wavenumbers, consistent with palla-
dium coordination to the imino nitrogen atom [26,27],
and a band at 350 cm−1 assigned to the w(PdꢁCl)
vibration.
The structure has been confirmed by the X-ray crys-
tal structure determination of 1.
1,4-(CꢀN(H)CH2CH2Me2)2-2,5-Cl2C6H2 was treated
with Pd(OAc)2 and Li2[PdCl4], but no cyclometallated
compound was isolated. Reduction of the Pd(II) salts
to Pd(0) was observed. No reaction with the CꢁCl
bonds took place, as has been described before [28].
Treatment of 1 with thallium acetylacetonate gave
the dinuclear complex [(H3CCOCHCOCH3)Pd{Me2-
NCH2CH2N ꢀ (H)C}C6H2{C(H) ꢀ NCH2CH2NMe2}Pd-
(H3CCOCHCOCH3)] (2) as an air-stable solid which
was fully characterized. The 1H-NMR spectrum
showed the characteristic signals corresponding to the
metallated ligand as well as the resonances correspond-
ing to the coordinated acac ligand (l (CH) 5.35s ppm,
l (Me) 2.01s ppm). The singlet at 2.30 ppm was as-
signed to the NMe2 group (the same shift was observed
for the uncoordinated ligand) showing the cleavage of
Fig. 1.

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
87
the PdꢁNMe2 bond. In the 13C-{1H} spectrum the
separation of the two methylene resonances was ca. 3
ppm, confirming cleavage of the PdꢁNMe2 bond. The
13C-{1H} spectrum showed singlets at l 100.17 and l
27.48 ppm for the CH and CꢁMe carbons, respectively.
Reaction of 1 with tertiary monophosphines afforded
the binuclear cyclometallated complexes [(L)(Cl)Pd-
{Me2NCH2CH2N ꢀ (H)C}C6H2{C(H) ꢀ NCH2CH2-
NMe2}Pd(Cl)(L)] (L=PPh3, 3; L=PMePh2, 5; L=
PEtPh2, 6; L=PEt2Ph, 7) as pure air-stable solids
which were fully characterized (see Table 1 and Section
2. This shift has not been observed in mononuclear
analogue complexes derived form terdentate Schiff
bases [11]. We attribute this finding to the shielding
effect of a phosphine phenyl ring that lies close to the
HCꢀN as a consequence of the binuclear structure of
the complex.
The IR spectra showed the w(PdꢁCl) band in the
range 281–301 cm−1 confirming the presence of the
chlorine atom in the coordination sphere of palladium.
Treatment of 1 with silver perchlorate followed by
reaction with triphenylphosphine in 1–diphosphine 1:2
molar ratio yielded the doubly cyclometallated complex
[(PPh3)Pd{Me2NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2-
CH2NMe2}Pd(PPh3)][ClO4]2 (4) which was fully charac-
terized (see Section 3 and Table 1). Electric conductiv-
ity measurements in dry acetonitrile solution showed
1
3). The H-NMR spectra of the complexes showed the
singlet resonance assigned to the NMe2 protons at ca. l
2.25 ppm as corresponds to a non-coordinated amine
nitrogen. The HCꢀN resonance appeared at ca. l 7.2
ppm, high field shifted as compared to complexes 1 and
Scheme 1. (i) [Pd2(dba)3]–benzene; (ii) Tl(acac)–chloroform; (iii) PR3–acetone; (iv) AgClO4 followed by PPh3–acetone.

88
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
Scheme 2. (v) dppp one equivalent–acetone; (vi) AgClO4 followed by dppb one equivalent–acetone; (vii) diphosphine two equivalents–acetone;
(viii) triphos–acetone.
the complex to be 1:2 electrolyte [29]. In the IR spec-
trum, the absence of the w(PdꢁCl) band showed chlo-
ride abstraction as AgCl. The coupling constant J(PH)
Treatment of 1 with the tertiary diphosphine 1,3-bis
(diphenylphosphino)propane (dppp) in a complex of
1–phosphine with a 1:1 molar ratio gave the cy-
clometallated complex [{m-Ph2P(CH2)3PPh2}(Cl)Pd-
{Me2NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}
(Cl)Pd{m-Ph2P(CH2)3PPh2}]2 (8). The lNMe2 reso-
nance appeared as a singlet at l 2.24 ppm showing
PdꢁNMe2 bond cleavage. The H3, H6 resonances
showed JPH coupling (JPH=3.8 Hz). The phosphorus
resonance appeared as a singlet at l 30.6 ppm in the
31P-{1H} NMR showing the high symmetry of the
complex. The mass (FAB) spectrum for 8 showed peaks
at 1005 [1/2M+Cl] and 933 [1/2M−Cl], but no peak
was found for the tetranuclear ion, nevertheless similar-
1
to H3, H6 (4.2 Hz) in the H spectrum, as well as the
phosphorus chemical shift (l 39.7 ppm) showed the
palladium trans to phosphorus and cis to carbon dispo-
sition. Therefore, the phosphine ligand occupies the
coordination site that was left vacant after removal of
the chlorine atom. The l NMe2 resonances were oc-
cluded by the NMR solvent (DMSO) resonances ca. l
2.2 ppm; a value close to that observed for compound
1 (l 2.70 ppm) would be expected. We suggest the
lower l value is due to shielding of the phosphine
phenyl rings [11].

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
89
ity with related complexes derived from doubly cy-
clometallated Schiff bases points towards a tetranuclear
structure [30]. The relatively large solubility of the
complex in the usual organic solvents sustains this
conjecture.
NMR spectrum, which appeared as a singlet at l 28.43
ppm [31]. Conductivity measurements carried out in dry
acetonitile showed higher values than expected for 2:1
electrolytes and smaller than for 4:1 electrolytes. We
were unable to obtain a clear mass spectrum of 9,
therefore we tentatively assign a tetranuclear structure
for the complex.
Treatment of 1 with silver perchlorate followed by
reaction with the tertiary diphosphine 1,4-bis
(diphenylphosphino)butane (dppb) in a 1–diphosphine
1:1 molar ratio yielded the tetranuclear complex [{m-
Ph2P(CH2)4PPh2)}-Pd{Me2NCH2CH2Nꢀ(H)C} C6H2-
{C(H) ꢀ NCH2CH2NMe2}Pd{m - Ph2P(CH2)4PPh2}]2-
Reaction of 1 with the tertiary diphosphines 1,2-bis
(diphenylphosphino)ethane (dppe) and cis-1,2-bis
(diphenylphosphino)ethene (cis-dppe), followed by
treatment with ammonium hexafluorophosphate in the
latter case, in a complex of 1–diphosphine 1:2 molar
ratio, yielded the binuclear cyclometallated complexes
[{Ph2P(CH2)2PPh2 - P,P}Pd{Me2NCH2CH2N ꢀ (H)C}
1
[ClO4]4 (9). The H-NMR spectrum of the complex is
similar to the one for 4 with the HCꢀN and H3, H6
resonances coupled to the 31P nuclei. This was confi-
rmed by the shift of the 31P resonance in the 31P-{1H}-
C6H2{C(H)
ꢀ NCH2CH2NMe2}Pd{Ph2P(CH2)2PPh2-
Table 1
31P- and 1H-NMR data a,b,c,d
l(HiCꢀN)
l(H3, H6)
8.05s
l(CH2) i
l(NMe2)
2.30s
l(P) j
L
8.65t
3.78(13.6)
2.65
3.89(11.8)
2.93
4J(HiCH2) 1.3
7.94s
1
7.55s
2.70s
2 k
3
7.96s
7.38s
3.72(13.4)
2.69
3.85
2.72
3.81
2.87
3.83(12.2)
2.65
3.85
2.68
2.30s
7.20s
6.07br
2.24s
38.5s
39.7s
20.9s
33.9s
31.9s
30.6s
28.4s
4 e,l
5
6.10d
f
g
4J(PH) 4.2
5.99s
7.13s
7.16s
7.29d
2.24s
2.26s
2.28s
2.24s
2.04s
1.86s
6
6.09s
7
6.12d
3.88
4J(PHi) 6.6
4J(PH) 4.3
5.97d
2.70
f
h
8
4J(PH) 3.8
6.45d
h
9
7.87d
4J(PHi) 9.9
7.36d
4J(PH) 5.0
6.54m
10 m
3.16
58.5d
40.9d
4J(PHi) 8.9
h
J(PP) 41.8
56.9br
48.9br
11
12
7.39d
6.94d
3.35(12.2)
1.80
1.93s
1.97s
4J(PHi) 7.8
4J(PH) 12.5
4J(PH) 7.5
6.94d
f
h
90.4t
44.5d
4J(PH) 5.7
J(PP) 26.4
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; t, triplet; m, multiplet; br, broad.
e In DMSO-d6.
f Occluded by phenyl (phosphine) resonances.
g Occluded by solvent resonances.
h Occluded by methylene (phosphine) resonances.
i The higher value was assigned to the CꢀNCH2 protons and the lower one to the CH2NMe2 protons; N values in parentheses.
j For 10 and 11 l(P-trans-C)Bl(P-trans-N) and for 12 l(P-trans-C)\l(P-trans-P).
k acac: l(CH) 5.35s ppm, l(Me) 2.01s ppm.
l Phosphine: l(MeP)=2.22d. 2J(PMe)=10.4 Hz.
m l(PF6)=146.1m ppm.

90
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
P,P}]/[PF6]2 (10) and [(cis-Ph2PCHꢀCHPPh2P,P)Pd-
{Me2NCH2CH2N ꢀ (H)C}C6H2{C(H) ꢀ N/CH2CH2N-
Me2}Pd(cis-Ph2PCHꢀCHPPh2-P,P)][Cl]2 (11) as air-
stable solids which were fully characterized (see Section
3 and Table 1). Electric conductivity measurements
showed the complexes to be 1:2 electrolytes. The 31P-
{1H}-NMR spectra showed two doublets for 10
(JPP=41.8 Hz) and two broad signals for 11, the
resonance at lower frequency was assigned to the phos-
phorus nucleus trans to the phenyl carbon atom in
accordance with the higher trans influence of the latter
with respect to the CꢀN nitrogen atom [32]. In the
1H-NMR, the HCꢀN resonance was coupled only to
the 31P nucleus trans to nitrogen, and the H3, H6
resonances were coupled to both phosphorus nuclei.
The l NMe2 resonance was shifted to a lower frequency
as a consequence of the PdꢁNMe2 bond cleavage.
Treatment of 1 with the tertiary triphosphine bis(2-
diphenylphosphinoethyl)-phenylphosphine in 1:2 molar
ratio gave the complex [{(Ph2PCH2CH2)2PPh-P,P,P}-
Pd{Me2NCH2CH2N ꢀ (H)C}C6H2{C(H) ꢀ NCH2CH2-
NMe2}Pd/{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]2 (12). The
compound was a 1:2 electrolyte as shown by the con-
ductivity measurement in dry acetonitrile. The phos-
phorus resonances in the 31P-{1H}-NMR spectra were
downfield shifted from their values in the free phos-
phine suggesting coordination of all the phosphorus
atoms to the metal center. 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 lower frequency in accordance with the
high trans influence of the phosphine ligand [32]. The
H3 and H6 proton resonances were only coupled to the
central phosphorus nucleus with J(PH5) 5.7 Hz; no
coupling was observed between H3, H6 and the termi-
nal phosphorus nuclei in accordance with the ca. 90°
angle between the metallated phenyl ring and the plane
defined by the metallated carbon, the terminal phos-
phorus and the palladium atom. These observations are
in agreement with coordination of the palladium atom
to the carbon atom and to three phosphorus atoms,
with subsequent PdꢁNMe2 and PdꢁCl bond cleavage,
as shown by the high-field shift of the resonance corre-
sponding to the NMe2 protons related to 1, as well as
the absence of a w(PdꢁCl) band in the IR spectrum. The
HCꢀN resonances were occluded by the signals of the
phosphine protons. These findings were confirmed by
the resolution of the X-ray crystal structure of com-
pound 12.
Fig. 2. Molecular structure of complex [(Cl)Pd{Me2NCH2CH2Nꢀ
(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd(Cl)], 1, with labelling
scheme. Hydrogen atoms have been omitted for clarity.
Table 2
Crystal and structure refinement data
1
12
Formula
C16H24Cl2N4Pd2·
0.5CH2Cl2
598.55
[C84H92N4P4Pd2]
2Cl·CHCl3·H2O
1762.50
Mr
Temperature
(K)
293(2)
293(2)
,
Wavelength (A) 0.71073
0.71073
Monoclinic
P21/n
Crystal system
Space group
Monoclinic
P21/c
Cell dimensions
,
a (A)
11.989(1)
12.914(1)
17.014(1)
110.146(1)
2473.1(2)
4
17.409(5)
23.699(11)
21.977(6)
90.68(1)
9067(6)
,
b (A)
,
c (A)
i (°)
V (A )
3
,
Z
4
v (mm−1
)
1.608
0.693
Crystal size
(mm)
0.05×0.20×0.50
0.73×0.24×0.24
2qmax (°)
Reflections
collected
Reflections
unique
56.6
16 744
45.2
13 958
6128 (Rint=0.05)
11 846 (Rint=0.08)
Transmissions
Number of
parameters
Number of
restraints
S
0.92, 0.47
257
no abs. corr.
959
88
15
1.025
1.002
R [F, I\2|(I)] 0.0662
0.0968
0.2916
2.1. Crystal structure of [(Cl)Pd{Me2NCH2CH2Nꢀ
(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd(Cl)] (1)
wR [F2, all
data]
0.1951
Max D/|
0.000
1.581
0.001
1.148
3
Suitable crystals of the title compound were grown
by slowly evaporating a dichloromethane solution. The
,
Max z (e A )

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
91
Table 3
Selected bond Lengths (A) and angles (°) for 1
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 structure of 1 comprises a centrosymmetric
molecule of [(Cl)Pd{Me2NCH2CH2Nꢀ(H)C}C6H2-
{C(H)ꢀNCH2CH2NMe2}Pd(Cl)] (two similar half
molecules per asymmetric unit) and one 50% occupancy
dichloromethane solvent molecule.
Each palladium is bonded in a slightly distorted
square-planar geometry to a carbon atom of the phenyl
ring, the imine and amine nitrogen atoms and to the
chlorine atom. The mean deviations from the coordina-
,
Pd(1)ꢁN(1)
Pd(1)ꢁC(1)
Pd(1)ꢁN(2)
Pd(1)ꢁCl(1)
C(1)ꢁC3(1)
C(3)ꢁC(4)
C(4)ꢁN(1)
1.969(6)
2.001(6)
2.169(6)
2.304(2)
1.401(10)
1.435(9)
1.278(9)
Pd(2)ꢁN(3)
Pd(2)ꢁC(11)
Pd(2)ꢁN(4)
Pd(2)ꢁCl(2)
C(11)ꢁC(13)
C(13)ꢁC(14)
C(14)ꢁN(3)
1.973(6)
1.969(7)
2.187(7)
2.303(2)
1.418(9)
1.497(10)
1.242(9)
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)
80.7(3)
163.3(3)
82.7(2)
98.3(2)
98.4(1)
C(11)ꢁPd(2)ꢁN(3)
C(11)ꢁPd(2)ꢁN(4)
N(4)ꢁPd(2)ꢁN(3)
C(11)ꢁPd(2)ꢁCl(2)
N(4)ꢁPd(2)ꢁCl(2)
81.9(3)
163.6(3)
82.0(3)
96.7(2)
99.4(2)
,
tion planes are 0.0218 and 0.0203 A. The angles be-
tween adjacent atoms in the coordination sphere of
palladium are in the range 80.7(3)–99.4(2)°. The angles
CꢁPdꢁNimine and NimineꢁPdꢁNamine are less than 90° (in
the range 80.7(3)–82.7°(2) for C(1)ꢁPd(1)ꢁN(1) and
N(1)ꢁPd(1)ꢁN(2) angles, respectively) and the angles
CꢁPdꢁCl and NamineꢁPdꢁCl are thus \90° (in the
range 96.7(2)–99.4(2)° for the angles C(11)ꢁPd(2)ꢁCl(2)
and N(4)ꢁPd(2)ꢁCl(2), respectively).
,
The PdꢁNimine (1.969(6) and 1.973(6) A) and
,
PdꢁNamine (2.169(6) and 2.187(7) A) bond distances are
similar to others reported for related compounds,
[14,16,33]. The PdꢁN(2) bond length, longer than the
PdꢁN(1) distance, shows the strong trans influence of
the donor ligand.
The Pd(1)ꢁC(1) and Pd(2)ꢁC(11) bond distances of
,
2.001(6) and 1969(7) A, respectively, are somewhat
shorter than the values predicted from their covalent
radii [34], but similar to values found earlier [14,16].
,
The PdꢁCl bond distances (2.304(2), 2.303(2) A) are in
accordance with the values found early in similar cy-
clometallated compounds [35–37].
Fig. 3. Molecular structure of complex [{(Ph2PCH2CH2)2PPh-
P,P,P}Pd{Me2NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd-
{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]2, 12, with labelling scheme. Hydro-
gen atoms have been omitted for clarity.
2.2. Crystal structure of [{(Ph2PCH2CH2)2PPh-
P,P,P}Pd{Me2NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2-
CH2NMe2}Pd{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]2 (12)
Table 4
Suitable crystals of the title compound were grown
by slowly evaporating a chloroform solution. The
molecular structure is illustrated in Fig. 3. Crystal data
are given in the Table 2 and selected bond distances
and angles with estimated standard deviations are
shown in Table 4.
,
Selected bond Lengths (A) and angles (°) for 12
Pd(1)ꢁC(2)
Pd(1)ꢁP(1)
Pd(1)ꢁP(3)
Pd(1)ꢁP(2)
Pd(1)ꢁN(1)
2.086(14)
2.323(4)
2.327(4)
2.329(4)
2.429(13)
Pd(2)ꢁC(5)
Pd(2)ꢁP(6)
Pd(2)ꢁP(5)
Pd(2)ꢁP(4)
Pd(2)ꢁN(2)
2.067(14)
2.303(4)
2.306(4)
2.318(5)
2.415(13)
The structure of 10 comprises the [{(Ph2-
PCH2CH2)2PPhP,P,P}Pd{Me2NCH2CH2Nꢀ(H)C}C6-
H2{C(H)ꢀNCH2CH2NMe2}Pd{(Ph2PCH2CH2)2PPh-
P,P,P}]2+ cation, two chloride anions, two half-occu-
pancy chloroform and two half-occupancy water sol-
vent molecules. Each palladium is bonded to three
phosphorus atoms from the terdentate bis(2-di-
phenylphosphinoethyl)phenylphosphine and to an ortho
carbon atom of the Schiff base phenyl ring. An addi-
tional fifth bond constituted by a weak interaction
P(1)ꢁPd(1)ꢁP(3) 133.80(16)
P(1)ꢁPd(1)ꢁN(1) 112.3(4)
P(3)ꢁPd(1)ꢁN(1) 113.5(3)
P(6)ꢁPd(2)ꢁP(4) 143.48(17)
P(6)ꢁPd(2)ꢁN(2) 112.4(3)
P(4)ꢁPd(2)ꢁN(2) 103.9(3)
C(2)ꢁPd(1)ꢁN(1)
C(2)ꢁPd(1)ꢁP(1)
C(2)ꢁPd(1)ꢁP(3)
P(1)ꢁPd(1)ꢁP(2)
P(3)ꢁPd(1)ꢁP(2)
76.6(5)
C(5)ꢁPd(2)ꢁN(2)
C(5)ꢁPd(2)ꢁP(4)
C(5)ꢁPd(2)ꢁP(6)
P(5)ꢁPd(2)ꢁP(4)
P(6)ꢁPd(2)ꢁP(5)
75.8(5)
92.3(4)
92.4(4)
84.50(15)
85.71(15)
93.0(4)
91.8(4)
85.80(17)
84.93(16)
P(2)ꢁPd(1)ꢁN(1) 110.0(3)
C(2)ꢁPd(1)ꢁP(2) 173.4(5)
P(5)ꢁPd(2)ꢁN(2) 111.6(3)
C(5)ꢁPd(2)ꢁP(5) 172.6(5)

92
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
between the imino nitrogen atoms and their respective
trophotometer. NMR spectra were obtained as CDCl3
or (CD3)2SO solutions and referenced to SiMe4 (1H and
13C) or 85% H3PO4 (31P-{1H}) and were recorded on
Bruker WM-250 and AMX-300 spectrometers. All
chemical shifts were reported downfield from standards.
The synthesis of 1,4-(CꢀN(H)CH2CH2Me2)2-2,5-
Cl2C6H2 was performed by heating a chloroform solu-
tion of the appropriate quantities of 2,5-dichloro-
terephthaldehyde and N,N-dimethylethylenediamine in
a Dean–Stark apparatus under reflux. 13C-{1H}-NMR
(75.48 MHz, CDCl3): l 152.0 (CꢀN); l 133.4 (C1, C4);
l 128.4 (C2, C5); l 124.1 (C3, C6); l 54.6 (CH2); l 46.0
palladium atoms is observed (Pd(1)ꢁN(1) and
,
Pd(2)ꢁN(2) distances of 2.429(13) and 2.415(13) A,
respectively). The geometry around the palladium
atoms may be considered as being distorted bypirami-
dal trigonal. The equatorial plane is formed by the
palladium atom, the imino nitrogen atom and the ter-
minal phosphorus atoms (Pd(1), N(1), P(1), P(3) plane
1; Pd(2), N(2), P(4), P(6), plane 2). The metallated
carbon and the central phosphorus complete the coor-
dination sphere. The most noticeable distortions corre-
spond to the enlarged P(1)ꢁPd(1)ꢁP(3) and
P(6)ꢁPd(2)ꢁP(4) bond angles of 133.80(16) and
143.48(17)°, and the reduced P(4)ꢁPd(2)ꢁN(2) angle of
103.9(3)°. The bond angles C(2)ꢁPd(1)ꢁN(1) and
C(5)ꢁPd(2)ꢁN(2) of 76.6(5) and 75.8(5)° are also
smaller than the expected 90° consequent upon
chelation.
(NMe2). IR: w(CꢀN), 1627s cm−1
.
CAUTION: Perchlorate salts of metal complexes are
potentially explosive. Extreme caution should be exer-
cised when handling this material.
The PdꢁN bond lengths are longer than the PdꢁN
3.1. Preparation of [(Cl)Pd{Me2NCH2CH2Nꢀ
(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd(Cl)] (1)
,
bond length of 2.23(2) A in an authentic five-coordinate
Pd(II) complex [38]. Nevertheless, some five-coordi-
nated palladium(II) compounds with the PdꢁN bond
1,4-(CꢀN(H)CH2CH2Me2)2-2,5-Cl2C6H2 (112 mg,
0.33 mmol) and tris(dibenzylideneacetone)dipalla-
dium(0) (300 mg, 0.33 mmol) were added to 25 cm3 of
benzene to give a dark red solution which was heated
under reflux for 2 h. After cooling to r.t. the solvent
was removed under vacuum to give a dark yellow solid
which was chromatographed on a column packed with
silica gel. Elution with dichloromethane–ethanol (1%)
afforded the final product as a yellow solid after con-
centration. Yield 65%. Anal. Found: C, 34.7; H, 4.2; N,
9.8. C16H24Cl2N4Pd2 Calc.: C, 34.5; H, 4.3; N, 10.1%.
,
length in the range 2.359(4)–2.805(5) A have been
described by us [15,23] and others before [39]. The
Pd(1)ꢁC(2) and Pd(2)ꢁC(5) bond lengths of 2.086(14)
,
and 2.067(15) A are similar to those found in related
cyclometallated complexes [15,23], with C trans to
phosphorus but longer than PdꢁC distances found in
cyclometallated complexes with carbon trans to nitro-
gen or chlorine supporting a phosphine ligand in the
trans position. The PdꢁP bond lengths (Pd(1)ꢁP(1),
2.323(4); Pd(1)ꢁP(2), 2.329(4); Pd(1)ꢁP(3), 2.327(4);
Pd(2)ꢁP(4), 2.318(5); Pd(2)ꢁP(5), 2.306(4); Pd(1)ꢁP(3),
IR: w(CꢀN), 1600s cm−1; w(PdꢁCl), 350m cm−1 13C-
.
2.303(4) A) are similar to those found in related Pd(II)
{1H}-NMR (75.48 MHz, CDCl3): l 173.4 (CꢀN); l
151.4 (C2, C5); l 134.0 (C3, C6); l 62.9, 53.2 (CH2); l
47.4 (NMe2).
,
complexes [15,23,40] and suggest that a slightly partial
double bond between the palladium and phosphorus
atoms may exist [41].
3.2. Preparation of [(H3CCOCHCOCH3)Pd{Me2-
NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}-
Pd(H3CCOCHCOCH3)] (2)
3. Experimental
All reactions were carried out in an atmosphere of
dry nitrogen. Solvents were purified by standard meth-
ods [42]. Chemicals were reagent grade. Tris(dibenzyli-
deneacetone)dipalladium(0), thallium acetylacetonate
and silver perchlorate were purchased from Aldrich-
Chemie. The diphosphines Ph2(CH2)2Ph2 (dppe),
Ph2(CH2)3Ph2 (dppp), Ph2(CH2)4Ph2 (dppb) and the
triphosphine (Ph2PCH2CH2)2PPh (triphos), were pur-
chased from Aldrich-Chemie; cis-PPh2CHꢀCHPPh2
(cis-1,2-dppe) was prepared according to procedures
described elsewhere [43]. Microanalyses were carried
out using a Carlo-Erba Elemental Analyzer, Model
1108. IR spectra were recorded as Nujol mulls or KBr
discs on a Perkin–Elmer 1330 and on a Mattson spec-
To a suspension of 1 (40 mg, 0.07 mmol) in chloro-
form (25 cm3), thallium acetylacetonate (44 mg, 0.14
mmol) was added and the mixture stirred at r.t. for 12
h. The solution was filtered to eliminate the TlCl pre-
cipitate and the solvent removed to give the desired
complex as a yellow solid which was recrystallized from
dichloromethane–hexane. Yield 78%. Anal. Found: C,
45.2; H, 6.6; N, 8.0. C26H44N4O4Pd2 Calc.: C, 45.3; H,
6.4; N, 8.1%. w(CꢀN), 1604s cm−1; 2,4-Pentanedionate:
w(CꢀC), 1512s cm−1; IR: w(CꢀO), 1577s, 1389s cm−1
.
13C-{1H}-NMR (75.48 MHz CDCl3): l 175.0 (CꢀN); l
151.5 (C2, C5); l 146.6 (C1, C4); l 128.5 (C3, C6); l
100.17 (CH, acac); l 58.7, 55.8 (CH2); l 45.7 (NMe2); l
27.48 (Me, acac).

A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
93
3.3. Preparation of [(PPh3)(Cl)Pd{Me2NCH2CH2Nꢀ
(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd(Cl)(PPh3)] (3)
yellow precipitate was filtered and dried in vacuo. Yield
87%. Anal. Found: C, 53.3; H, 5.1; N, 5.7.
C43H50Cl2N4P2Pd2 Calc.: C, 53.3; H, 5.2; N, 5.8%. IR:
PPh3 (38 mg, 14 mmol) was added to a suspension of
1 (40 mg, 0.72 mmol) in acetone (15 cm3). The mixture
was stirred for 4 h at r.t., the resulting yellow solid was
filtered off and recrystallized from dichloromethane–
hexane. Yield 85%. Anal. Found: C, 57.5; H, 5.0; N,
5.5. C52H54Cl2N4P2Pd2 Calc.: C, 57.8; H, 5.0; N, 5.2%.
w(CꢀN), 1611s cm−1; w(PdꢁCl), 272m cm−1
.
Compound 9 was synthesised following a similar
procedure to that for 4 but using a 1–diphosphine 1:1
molar ratio.
3.9. [{v-Ph2P(CH2)4PPh2}Pd{Me2NCH2CH2Nꢀ
(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd{v-
Ph2P(CH2)4PPh2}]2[ClO4]4 (9)
IR: w(CꢀN), 1618s cm−1; w(PdꢁCl), 286w cm−1
.
Compounds 5, 6 and 7 were obtained following a
similar procedure as white solids.
Yield 75%. Anal. Found: C, 47.7; H, 4.8; N, 5.0.
C44H52N4O8Cl2P2Pd2 requires: C, 47.6; H, 4.7; N, 5.0.
IR: w(CꢀN), 1637s cm−1. \M=320 ohm−1 cm2 mol−1
(in acetonitrile).
3.4. [(PMePh2)(Cl)Pd{Me2NCH2CH2Nꢀ(H)C}C6H2-
{C(H)ꢀNCH2CH2NMe2}Pd(Cl)(PMePh2)] (5)
Yield 77%. Anal. Found: C, 52.7; H, 5.2; N, 5.8.
C42H50Cl2N4P2Pd2 Calc.: C, 52.7; H, 5.3; N, 5.9%. IR:
3.10. Preparation of [{Ph2P(CH2)2PPh2-P,P}Pd{Me2-
NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀN-CH2CH2NMe2}-
Pd{Ph2P(CH2)2PPh2-P,P}][PF6]2 (10)
w(CꢀN), 1620s cm−1; w(PdꢁCl), 301w cm−1
.
3.5. [(PEtPh2)(Cl)Pd{Me2NCH2CH2Nꢀ(H)C}C6H2-
{C(H)ꢀNCH2CH2NMe2}Pd(Cl)(PEtPh2)] (6)
Ph2P(CH2)2PPh2 (57 mg, 0.14 mmol) was added to a
suspension of 1 (40 mg, 0.072 mmol) in acetone (15
cm3). The mixture was stirred for 4 h, after which
ammonium hexafluorophosphate was added. The com-
plex was the precipitated out by addition of water,
filtered off and dried in vacuo. Recrystallization from
chloroform–hexane gave the final compound as a yel-
low solid.
Yield 96%. Anal. Found: C, 54.0; H, 4.7; N, 3.9.
C68H72F12N4P4Pd2 Calc.: C, 54.1; H, 4.8; N, 3.7%. IR:
w(CꢀN), 1609m cm−1. \M=300 ohm−1 cm2 mol−1 (in
acetonitrile).
Yield 68%. Anal. Found: C, 54.0; H, 5.5; N, 5.4.
C44H54Cl2N4P2Pd2 Calc.: C, 53.7; H, 5.5; N, 5.7%. IR:
w(CꢀN), 1615s cm−1; w(PdꢁCl), 281m cm−1
.
3.6. [(PEt2Ph)(Cl)Pd{Me2NCH2CH2Nꢀ(H)C}C6H2-
{C(H)ꢀNCH2CH2NMe2}Pd(Cl)(PEt2Ph)] (7)
Yield 93%. Anal. Found: C, 48.0; H, 6.1; N, 6.3.
C36H54Cl2N4P2Pd2 Calc.: C, 48.7; H, 6.1; N, 6.3%. IR:
w(CꢀN), 1611s cm−1; w(PdꢁCl), 293m cm−1
.
Compound 11 was obtained as a white solid follow-
ing a similar procedure to that for 8 but using a
1–diphosphine 1:2 molar ratio.
3.7. Preparation of [(PPh3)Pd{Me2NCH2CH2Nꢀ(H)C}-
C6H2{C(H)ꢀNCH2CH2NMe2}Pd(PPh3)][ClO4]2 (4)
3.11. [(cis-Ph2PCHꢀCHPPh2-P,P)Pd{Me2-
NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}-
Pd(cis-Ph2PCHꢀCHPPh2-P,P)][Cl]2 (11)
A suspension of 1 (40 mg, 0.72 mmol) in acetone (15
cm3) was treated with silver perchlorate (30 mg) and
stirred for 4 h. PPh3 (38 mg, 0.14 mmol) was added and
the resulting mixture stirred for 12 h. The solution was
filtered trough Cellite to eliminate the AgCl precipitate.
The solvent was removed and the product recrystallized
from dichloromethane–hexane to give the desired com-
plex as a yellow solid. Yield 87%. Anal. Found: C, 52.0;
H, 4.8; N, 4.9. C52H54Cl2N4O8P2Pd2 Calc.: C, 51.7; H,
4.5; N, 4.6%. IR: w(CꢀN), 1618m cm−1. \M=250
ohm−1 cm2 mol−1 (in acetonitrile).
Yield 82%. Anal. Found: C, 60.2; H, 5.3; N, 4.1.
C68H68Cl2N4P4Pd2 Calc.: C, 60.5; H, 5.0; N, 4.1%. IR:
w(CꢀN), 1608m cm−1. \M=285 ohm−1 cm2 mol−1 (in
acetonitrile).
Compound 12 was obtained as a yellow solid follow-
ing a similar procedure to that for 8 using a 1–trifos 1:2
molar ratio.
3.12. [{(Ph2PCH2CH2)2PPh-P,P,P}Pd{Me2NCH2-
CH2Nꢀ(H)C}C6H2{C(H)ꢀNCH2CH2NMe2}Pd-
{(Ph2PCH2CH2)2PPh-P,P,P}][Cl]2 (12)
3.8. Preparation of [{v-Ph2P(CH2)3PPh2}(Cl)Pd{Me2-
NCH2CH2Nꢀ(H)C}C6H2{C(H)ꢀN-CH2CH2NMe2}(Cl)
Pd{v-Ph2P(CH2)3PPh2}]2 (8)
Yield 76%. Anal. Found: C, 60.2; H, 5.4; N, 2.9.
C84H90Cl2N4P6Pd2 Calc.: C, 62.1; H, 5.6; N, 3.4%. IR:
w(CꢀN), 1611s cm−1. \M=263 ohm−1 cm2 mol−1 (in
acetonitrile).
Ph2P(CH2)3PPh2 (30 mg, 0.073 mmol) was added to a
suspension of 1 (40 mg, 0.072 mmol) in acetone (15
cm3). The mixture was stirred for 4 h and the resulting

94
A. Ferna´ndez et al. / Journal of Organometallic Chemistry 612 (2000) 85–95
3.13. Single-crystal X-ray diffraction analysis
Centre, CCDC Nos. 142880 and 142881 for compounds
1 and 12, respectively. 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 www:
http://www.ccdc.cam.ac.uk).
For complex 1 three-dimensional X-ray data were
collected at r.t. in the range 3.62B2qB56.66° on a
Siemens Smart CCD diffractometer by the omega scan
method. Reflections were measured from a hemisphere
of collected data, of frames each covering 0.3° in
omega. Of the 16 744 reflections measured, all of which
were corrected for Lorentz and polarisation effects and
for absorption by semi-empirical methods based on
symmetry-equivalent and repeated reflections, 3440 in-
dependent 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
with allowance for thermal anisotropy of all non-hy-
drogen atoms (except the disordered dichloromethane
solvent molecule). Hydrogen atoms were included in
calculated positions and refined in riding mode. One of
the CH2NMe2 groups was disordered with the carbon
atoms occupying two positions (C16, C16a, C17, C17a
and C18, C18a). The occupancies of the two pairs of
positions were tied to give an overall value of 1.0 and
then refined giving values of 0.5 for each component.
Acknowledgements
We would like to thank the Xunta de Galicia
(XUGA20913B96) for financial support.
References
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two ill defined dichloromethane solvent molecules from
the data. Two solvent voids were found (potential
3
[8] P. Espinet, M.A. Esteruelas, L.A. Oro, J.L. Serrano, E. Sola,
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,
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and refinement were carried out using the program
package SHELX-97 [45].
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For complex 12 three-dimensional, r.t. X-ray data
were collected in the range 3.7B2qB45.2° on a
Siemens P4 diffractometer by the omega scan method.
Of the 13 958 reflections measured, all of which were
corrected for Lorentz and polarisation effects, 5906
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 calculated positions
and refined in riding mode. Refinement converged at a
final R=0.0968 (wR2=0.2916 for all 11 846 unique
data, 959 parameters, mean and maximum l/| 0.000,
0.001), with allowance for the thermal anisotropy of all
non-hydrogen atoms. Geometric constrains were used
in all chloroform solvent molecules. The minimum and
maximum final electron densities were −0.875 and
1.148 e A−3. Complex scattering factors were taken
,
from the program package SHELXL-97 [45].
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4. Supplementary material
Crystallographic data (excluding structure factors)
for the structures reported in this paper have been
deposited with the Cambridge Crystallographic Data

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