Ferrocene-bridged Pd-NCN pincer complexes

Article abstract of DOI:10.1016/S0022-328X(03)00753-8

The meta-diaminoaryl ferrocene Fe[η⁵-C₅ H₄(NCNH)]₂ [NCNH=1-C₆H₃ (CH₂NMe₂)₂-3,5] (3) can be synthesised by the reaction of Fe[η⁵-C₅H₄(ZnCl)] ₂ (1) with I-C₆H₃(CH₂ NMe₂)₂-3,5 (2) in a 1:2 molar ratio in the presence of catalytic amounts of [Pd(PPh₃)₂]. The two meta-dimaminoaryl NCNH pincer units in 3 can be used to assemble multimetallic complexes. Thus, 3 produces on reaction with ^t BuLi and (Me₂S)₂PdCl₂ trimetallic Fe[η⁵-C₅H₄(NCN-4-PdCl)]₂ {NCN=1-C₆H₂(CH₂NMe₂) ₂-3,5} (6) along with heterobimetallic Fe[η⁵ -C₅H₄(NCNH)][η⁵-C₅ H₄(NCN-4-PdCl)] (5). Complex 6 contains two bis-ortho-chelated pincer NCN-PdCl units, whereas 5 possesses one bis- ortho -chelated NCN pincer entity and one non-metallated NCNH moiety. Complex 6 is the first example in organometallic chemistry in which two bis-ortho-chelated diaminoaryl palladium units are bridged via the respective para C-atoms spanned by a redox-active ferrocenyl building block.

Full text of DOI:10.1016/S0022-328X(03)00753-8

Journal of Organometallic Chemistry 684 (2003) 230ꢀ234
/
www.elsevier.com/locate/jorganchem
Ferrocene-bridged Pdꢀ
/
NCN pincer complexes
Stefan Kocher a, Gerard P.M. van Klink b, Gerard van Koten b, Heinrich Lang a,*
¨
a Technische Universitat Chemnitz, Fakultat fur Naturwissenschaften, Institut fur Chemie, Lehrstuhl Anorganische Chemie, Straße der Nationen 62, D-
¨
¨
¨
¨
09111 Chemnitz, Germany
b Department of Metal-Mediated Synthesis, Utrecht University, Debye Institute, Padualaan 8, 3584 CH Utrecht, The Netherlands
Received 10 March 2003; received in revised form 30 June 2003; accepted 30 June 2003
Dedicated to Prof. E.O. Fischer on the occasion of his 85th birthday
Abstract
The meta-diaminoaryl ferrocene Fe[h5-C5H4(NCNH)]2 [NCNHꢁ
of Fe[h5-C5H4(ZnCl)]2 (1) with Iꢀ
C6H3(CH2NMe2)2-3,5 (2) in a 1:2 molar ratio in the presence of catalytic amounts of [Pd(PPh3)2].
The two meta-dimaminoaryl NCNH pincer units in 3 can be used to assemble multimetallic complexes. Thus, 3 produces on
/1-C6H3(CH2NMe2)2-3,5] (3) can be synthesised by the reaction
/
t
reaction with BuLi and (Me2S)2PdCl2 trimetallic Fe[h5-C5H4(NCNꢀ
/
4-PdCl)]2 {NCNꢁ
/
1-C6H2(CH2NMe2)2-3,5} (6) along with
PdCl
heterobimetallic Fe[h5-C5H4(NCNH)][h5-C5H4(NCNꢀ
/
4-PdCl)] (5). Complex 6 contains two bis-ortho-chelated pincer NCNꢀ
/
units, whereas 5 possesses one bis-ortho-chelated NCN pincer entity and one non-metallated NCNH moiety. Complex 6 is the first
example in organometallic chemistry in which two bis-ortho-chelated diaminoaryl palladium units are bridged via the respective
para C-atoms spanned by a redox-active ferrocenyl building block.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Ferrocene; NCN pincer; Palladium; Multimetallic; Cyclic voltammetry
1. Introduction
In addition to monoanionic diphosphino- and di-
sulfido-aryl anions the organometallic chemistry of the
related
diaminoaryl
ligand
NCN
(NCNꢁ
/
[C6H3(CH2NMe2)2-2,6]ꢂ) has been investigated inten-
sively [1,2]. In pincer halide transition metal complexes
(structural type A molecule), for example, stable pal-
ladiumꢀ
/
carbon bonds are present, due to the chelating
effect of the monoanionic NCN ligand. [3] This opens
the possibility to synthesize para-functionalised Yꢀ
/
NCNꢀ
/
MX complexes, which can be used as building
Such complexes can be used, for example, for creating
materials with electronic conduction along p-conjugated
organometallic chains [5] or for the synthesis of liquid
crystalline materials. [6] The functionalities X or Y in
molecules of structural type A allow the introduction of
a second transition metal containing fragment (homo-
or heterobimetallic) in which the respective transition
metals are connected via conjugated organic units. The
synthesis of multimetallic assemblies is given by suitable
modification of both X and Y. While in the latter type of
molecules the transition metals are spanned by p-
blocks to prepare larger molecules. [4]
* Corresponding author. Tel.: ꢃ
/
49-371-531-1200; fax: ꢃ
/
49-371-
531-1833.
E-mail addresses: g.vankoten@chem.uu.nl (G. van Koten),
heinrich.lang@chemie.tu-chemnitz.de (H. Lang).
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00753-8

S. Kocher et al. / Journal of Organometallic Chemistry 684 (2003) 230ꢀ
/
234
231
¨
(1)
conjugated organic groups, to the best of our knowl-
edge, nothing is known about such systems in which X
or Y are redox-active organometallic bridging units.
We here report on the synthesis and subsequent
palladation of the 1,1?-bis-NCNH-pincer functionalised
25 8C (Eq. (1)). Complex 3 was isolated in 39% yield as a
brown oil.
As complex 3 contains two NCNH pincer units, it
should be possible to prepare heterobi- (FeM) or
trimetallic (FeM2) species (MꢁGroup-10 transition
/
ferrocene,
C6H3(CH2NMe2)2-3,5], to give novel trimetallic Fe[h5-
C5H4(NCNꢀ4-PdCl)]2.
Fe[h5-C5H4(NCNH)]2
[NCNHꢁ
/1-
metal atom). This could be achieved in a two-step
synthesis. Firstly, 3 was reacted with two equivalents of
tBuLi at low temperature to the corresponding ferroce-
/
nyl bis(aryllithium) compound Fe[h5-C5H4(NCNꢀ
/Li)]2
(Eq. (2)). Transmetallation of the latter dilithium
derivative with (Me2S)2PdCl2 gave the corresponding
2. Results and discussion
trimetallic compound Fe[h5-C5H4(NCNꢀ
/
PdCl)]2 (6)
Fe[h5-C5H4(NCNH)][h5-
PdCl)] (5) (Eq. (2)). The crude reaction
The synthesis of Fe[h5-C5H4(NCNH)]2 (3) was at-
tempted using different methods. Arylꢀaryl coupling
along
with
dimetallic
C5H4(NCNꢀ
/
/
product also contained traces of 3 and other yet
unidentified products. Nevertheless, separation of 5
and 6 from such impurities and side products appeared
of astonishing simplicity, because 3 could be removed by
extraction of the reaction product with hexane. Subse-
quently, 5 could be isolated by extraction with diethyl
ether and 6 with dichloromethane. After appropriate
work-up, 3 was isolated pure as a brown oil, while 5 and
6 were obtained as orange solids.
reactions can successfully be achieved by the Suzuki
reaction [7]. However, it appeared that the application
of this type of reaction, using either Fe(h5-C5H4I)2 and
(HO)2B[C6H3(CH2NMe2)2-3,5]
C5H4[B(OH)2]}2 and IC6H3(CH2NMe2)2-3,5 (2) as re-
actants, produced complex 3 in very low yield (5ꢀ9%). A
or
Fe{h5-
/
more suitable route for the synthesis of 3 involved the
reaction of Fe[h5-C5H4(ZnCl)]2 (1) [8] with two equiva-
lents of IC6H3(CH2NMe2)2-3,5 (2) in the presence of
catalytic amounts of [Pd(PPh3)2] in tetrahydrofuran at
The solubilities of 3, 5 and 6 increase with increasing
(2)

232
S. Kocher et al. / Journal of Organometallic Chemistry 684 (2003) 230ꢀ234
/
¨
Fig. 1. Cyclic voltammograms of 3 (dotted line) and 6 (solid line) in acetonitrile solutions at 25 8C.
number of Pd centres. A similar behaviour is found in
other multimetallic transition metal NCN pincer com-
plexes. [2,3,9] Whereas 3, 5 and 6 are stable in an inert
gas atmosphere over a long period of time it appeared
that on exposure to air they slowly start to decompose.
Notably the compounds with free NCN pincer units, i.e.
non-coordinating CH2NMe2 substituents, are less stable
than 6 in which both pincer units are cyclopalladated.
C6H2(CH2NMe2)2-3,5 fragments of 3 and 5. Accord-
ingly, C(4) in the 13C{1H}-NMR spectra has shifted to
lower field (3, 5 and 6; ArC(4) 127.7, 152.4 and 154.4
ppm). Similar downfield shifts are also typical for the
CH2 and NMe2 carbon atoms going from 3 to 5 to 6
(Section 3). All other resonance signals appear as well-
resolved signals in the expected region.
Cyclic voltammetric studies were carried out for
complexes 3 and 6 in acetonitrile solutions at 25 8C.
The obtained cyclic voltammograms are depicted in Fig.
1.
1
Complexes 3, 5 and 6 were fully characterized by H
and 13C(1H) spectroscopy. ESIꢀ
TOF (electrospray
ionisation time-of-flight) studies and elemental analysis
/
confirmed the proposed compositions.
1
As expected, the H-NMR spectrum of 3, 5 and 6 in
It was found that the Fe(II)/Fe(III) oxidation (Eꢁ
/
ꢃ
/
0.03 V, DEꢁ
/
80 mV) in 3 is reversible (Fig. 1), and is, as
CDCl3 showed AA?BB? patterns for the cyclopentadie-
nyl ring protons with coupling constants of 1.8 Hz.
Moreover, in 3 and 6 two pseudo-triplets between 4.1
and 4.5 ppm are observed, while in 5 four cyclopenta-
dienyl proton resonance signals appeared, due to lower
symmetry, when compared with 3 and 6. The CH2 and
NMe2 protons of the NCN ligands appear as singlets.
Upon coordination of the nitrogen atoms to the Pd
centres a significant shift of the CH2 and NMe2
resonances to lower field occurs (3, 5 and 6; NMe2:
2.25, 2.28/2.95 and 2.98; CH2: 3.40, 3.45/3.96 and 4.01
ppm). The presence of the 4-PdCl units in 5 and 6 are
obvious from the absence of the 4-CH proton in the 1-
compared to the FcH/FcHꢃ redox-couple, shifted to a
more positive value. This displacement can be inter-
preted by means of a stronger electron withdrawing
group present in 3 than in FcH, taken as standard. [10]
The cyclic voltammogram of 6 also exhibits a
reversible Fe(II)/Fe(III) redox couple at Eꢁ
/
ꢂ0.03 V
/
(DEꢁ100 mV). This potential is shifted by approxi-
/
mately 0.06 V to a more negative value, when compared
with 3. This shifting confirms that the iron center in 6 is
more easy to oxidize which is attributed to the electron
donating properties of the PdCl units. [11]
ESIꢀ
/
TOF MS studies on 3, 5 and 6 show in all cases
H); 5, 707.0
the molecular ion Mꢃ [3, 567.2 m/z (Mꢃꢃ
/

S. Kocher et al. / Journal of Organometallic Chemistry 684 (2003) 230ꢀ
/
234
233
¨
m/z (Mꢃꢃ
fragments for 5 and 6 are Mꢃꢂ
MeCN. For 6 also Mꢃꢂ H and Mꢃꢂ
PdClꢃ
(NCNH)2Hꢃ and
/
H); 6, 848.9 m/z (Mꢃꢃ
/
H)]. Further typical
Cl and Mꢃꢂ
Clꢃ
PdCl2ꢃ
3.2.1. Synthesis of Fe[h5-C5H4(NCNH)]2 (3)
/
/
/
At 0 8C, 1.60 g (5.81 mmol) of Fe(h5-C5H4Li)2×
/2/
/
/
/
/
3TMEDA was dissolved in 100 ml of tetrahydrofuran
and 1.59 g (11.63 mmol) of ZnCl2 was added in one
portion. After 1 h of stirring at this temperature a
separately prepared solution of [Pd(PPh3)2] [prepared by
treatment of 204 mg (0.29 mmol) of (Ph3P)2PdCl2 with
0.58 ml (0.58 mmol) of diisobutylaluminiumhydride in
30 ml of tetrahydrofuran] in 30 ml of tetrahydrofuran
was added. After additional 5 min of stirring, 1.85 g
(5.81 mmol) of IC6H3(CH2NMe2)2-3,5 (2), dissolved in
20 ml of tetrahydrofuran, was added. The dark brown
solution was allowed to warm to 25 8C. After stirring for
2 days, the reaction mixture was quenched with 50 ml of
4 M NaOH. The aqueous phase was separated and
extracted with 50 ml of chloroform. The combined
organic phases were dried over MgSO4, filtered and
evaporated in oil-pump vacuo. Chromatography over
neutral alumina with diethyl ether gave 175 mg (0.94
mmol, 16% based on 2) of Fe(h5-C5H5)2. By changing
H
are observed, while for 3
(NCNH)C6H3CH2NMe2ꢃ are characteristic.
3. Experimental
3.1. General methods
All reactions were carried out under an atmosphere of
purified nitrogen using standard Schlenk techniques.
Tetrahydrofuran, diethyl ether and hexane were purified
by distillation from sodiumꢀbenzophenone ketyl. ZnCl2
/
1
was dried with SOCl2. H-NMR spectra were recorded
with a Varian Inova 300 spectrometer operating at
300.10 MHz in the Fourier transform mode; 13C{1H}-
NMR spectra were recorded at 75.47 MHz. Chemical
shifts are reported in d units (parts per million) down-
the solvent to diethyl etherꢀtetrahydrofuran (4:1 mix-
/
ture) (h5-C5H5)Fe[h5-C5H4(NCNH)] (778 mg, 36%
based on 2) [14] could be obtained as a red oil. With
methanol as eluent the title complex 3 (643 mg, 39%
based on 2) could be isolated as a brown oil.
field from tetramethylsilane with the solvent as the
1
reference signal (CDCl3: H-NMR, dꢁ
/
7.26; 13C{1H}-
NMR, dꢁ77.0). Cyclic voltammograms were recorded
/
in a dried cell purged with purified nitrogen at 25 8C.
Platinum wires served as working electrode and as
counter electrode. A Ag/AgCl electrode served as
reference electrode. For ease of comparison, all elec-
trode potentials are converted using the redox potential
1H-NMR (CDCl3): [d] 2.25 (s, 24H, NMe2), 3.40 (s,
8H, CH2N), 4.14 (pt, JHH
JHH 1.8 Hz, 4H, C5H4), 7.06 (s, 2H, C6H3), 7.21 (s,
4H, C6H3). 13C{1H}-NMR (CDCl3): [d] 45.4 (NCH3),
64.4 (NCH2), 68.0 (CHꢀC5H4), 70.8 (CHꢀC5H4), 85.9
(iCꢀ
C5H4), 125.7 (CHꢀC6H3), 127.7 (CHꢀC6H3), 138.4
(iCꢀC6H3), 138.6 (iCꢀ
C6H3). ESIꢀTOF MS [m/z (rel.
int.)] 567.2 (100) [MꢃꢃH], 383.2 (20) [(NCNH)2Hꢃ],
ꢁ/1.8 Hz, 4H, C5H4), 4.50 (pt,
ꢁ
/
/
/
of the ferroceneꢀ
C5H5)2Fe] as the reference (Eꢁ
/
ferrocenium couple Fc/Fcꢃ [Fcꢁ
/
(h5-
/
/
/
/
0.00 V). Electrolyte
/
/
/
solutions were prepared from fresh distilled acetonitrile
and [NBu4]PF6 (dried in oil-pump vacuum at 120 8C).
The respective organometallic complexes were added at
/
249.2 (10) [(NCNH)C6H3CH2NMe2ꢃ]. Anal. Calc. for
C34H46FeN4 (566.59): C, 72.07; H, 8.18; N, 9.89. Found:
C, 71.96; H, 8.09; N, 9.64%.
cꢁ1 mM. CVs were recorded at a scan rate at 0.05 V
/
sꢂ1 using a Princeton Applied Research EG&G 263A
analyser.
3.2.2. Synthesis of Fe[h5-C5H4(NCNH)][h5-
Melting points were determined using sealed nitrogen
purged capillaries on a Gallenkamp melting point
apparatus. Microanalyses were performed by the Dornis
und Kolbe, Mikroanalytisches Laboratorium, Mulheim
¨
a.d. Ruhr and by the Department of Organic Chemistry
C5H4(NCNꢀ
/
PdCl)] (5) and Fe[h5-C5H4(NCNꢀ
/
PdCl)]2 (6)
tBuLi (0.27 ml, 0.41 mmol) (1.5 M in hexane) was
added to 103 mg (0.18 mmol) of Fe[h5-C5H4(NCNH)]2
(3), dissolved in 30 ml of hexane, at ꢂ80 8C. After
/
at Chemnitz Technical University. ESIꢀ
spectra were recorded with a Mariner ESIꢀ
/
TOF mass
stirring for 2 h and warming to 25 8C all volatiles were
removed in oil-pump vacuo. The light-brown residue
/TOF mass
spectrometer (Applied Biosystems) operating in the
positive-ion mode in a acetonitrile solution.
was dissolved in 30 ml of diethyl ether at ꢂ20 8C and
/
109 mg (0.36 mmol) of (Me2S)2PdCl2 were added in one
portion. The reaction mixture was stirred at 25 8C over
night and was evaporated. The dark brown residue was
3.2. General remarks
washed with hexane (2ꢄ
ether (2ꢄ30 ml) and then with dichloromethane (2ꢄ
ml).
/
5 ml), extracted with diethyl
/
/
30
Fe(h5-C5H4Li)2×
/2/3TMEDA
[12],
IC6H3(CH2-
NMe2)2-3,5 (2) [9] and (Me2S)2PdCl2 [13] were prepared
following published procedures. All other chemicals
were purchased from commercial sources and were
used without any further purification.
The combined diethyl ether extracts were evaporated
in vacuo to afford 20 mg (0.028 mmol, 16% based on 3)
of Fe[h5-C5H4(NCNH)][h5-C5H4(NCNꢀ
orange solid.
/PdCl)] (5) as

234
S. Kocher et al. / Journal of Organometallic Chemistry 684 (2003) 230ꢀ234
/
¨
Compound 5: m.p. 84 8C. 1H-NMR (CDCl3): [d] 2.28
(s, 12H, NMe2), 2.95 (s, 12H, NMe2), 3.45 (s, 4H,
References
[1] (a) For example see: J.M. Longmire, X. Zhang, M. Shang,
Organometallics 17 (1998) 4374;
CH2N), 3.96 (s, 4H, CH2N), 4.11 (pt, JHH
C5H4), 4.16 (pt, JHH 1.8 Hz, 2H, C5H4), 4.33 (pt,
JHH 1.8 Hz, 2H, C5H4), 4.52 (pt, JHH 1.8 Hz, 2H,
ꢁ1.8 Hz, 2H,
/
ꢁ
/
(b) P. Dani, M. Albrecht, G.P.M. van Klink, G. van Koten,
Organometallics 19 (2000) 4468;
ꢁ
/
ꢁ
/
C5H4), 6.76 (s, 2H, C6H2), 7.08 (s, 1H, C6H3), 7.26 (s,
2H, C6H3). 13C{1H}-NMR (CDCl3): [d] 45.0 (NCH3),
(c) D.E. Bergbreiter, P.L. Osburn, Y. Liu, J. Am. Chem. Soc. 121
(1999) 9531;
(d) H.P. Dijkstra, P. Steenwinkel, D.M. Grove, M. Lutz, A.L.
Spek, G. van Koten, Angew. Chem. Int. Ed. 38 (1999) 2186.
[2] (a) For example see: P. Steenwinkel, R.A. Gossage, G. van Koten,
Chem. Eur. J. 4 (1998) 759;
53.1 (NCH3), 64.0 (NCH2), 67.6 (CHꢀ
(CHꢀC5H4), 70.6 (CHꢀC5H4), 70.9 (CHꢀ
(NCH2), 83.4 (iCꢀC5H4), 85.1 (iCꢀ
C5H4), 117.7 (CHꢀ
C6H2), 124.1 (CHꢀC6H3), 125.8 (CHꢀC6H3), 133.0
(iCꢀC6H2), 135.6 (iCꢀC6H3), 137.1 (iCꢀ
C6H3), 142.8
(iCꢀC6H2), 152.4 (iCꢀ
C6H2). ESIꢀTOF MS [m/z (rel.
int.)] 711.0 (45) [Mꢃꢂ MeCN], 707.0 (30) [Mꢃꢃ
Clꢃ
H], 671.0 (100) [Mꢃꢂ
Cl]. Anal. Calc. for
/
C5H4), 68.0
/
/
/
C5H4), 74.7
/
/
/
/
/
(b) R.A. Gossage, L.A. van de Kuil, G. van Koten, Acc. Chem.
Res. 31 (1998) 423;
/
/
/
(c) M. Albrecht, G. van Koten, Angew. Chem. Int. Ed. Engl. 40
(2001) 3750.
/
/
/
/
/
/
[3] G. Rodr´ıguez, M. Albrecht, J. Schoenmaker, A. Ford, M. Lutz,
A.L. Spek, G. van Koten, J. Am. Chem. Soc. 124 (2002) 5127.
[4] (a) S. Back, W. Frosch, I. del Rio, G. van Koten, H. Lang, Inorg.
Chem. Commun. 2 (1999) 584;
/
C34H45ClFeN4Pd (707.47): C, 57.72; H, 6.41; N, 7.92.
Found: C, 56.84; H, 6.02; N, 7.36%.
(b) S. Back, M. Albrecht, A.L. Spek, G. Rheinwald, H. Lang, G.
van Koten, Organometallics 20 (2001) 1024.
The combined dichloromethane extracts were evapo-
rated in oil-pump vacuo to give 85 mg (0.096 mmol, 53%
[5] (a) For examples see: F. Coat, C. Lapinte, Organometallics 15
(1996) 477;
based on 2) of Fe[h5-C5H4(NCNꢀ
orange powder.
/
PdCl)]2 (6) as an
(b) D. Astruc, Acc. Chem. Res. 30 (1997) 383;
(c) M. Brady, W. Weng, Y. Zhou, J.W. Seyler, A. Amoroso, A.M.
Arif, M. Bohme, G. Frenking, J.A. Gladysz, J. Am. Chem. Soc.
¨
1
Compound 6: m.p. 172 8C (dec). H-NMR (CDCl3):
[d] 2.98 (s, 24H, NMe2), 4.01 (s, 8H, CH2N), 4.10 (pt,
119 (1997) 775.
[6] (a) T. Kaharu, H. Matsubara, S. Takahashi, J. Mater. Chem. 1
(1991) 145;
JHH
C5H4), 6.80 (s, 4H, C6H2). 13C{1H}-NMR (CDCl3): [d]
53.1 (NCH3), 67.2 (CHꢀC5H4), 70.7 (CHꢀC5H4), 74.6
(NCH2), 86.8 (iCꢀ C6H2), 134.9 (iCꢀ
C5H4), 117.6 (CHꢀ
C6H2), 144.7 (iCꢀC6H2), 154.4 (iCꢀ
C6H2). ESIꢀTOF
MS [m/z (rel. int.)] 853.9 (30) [Mꢃꢂ
ClꢃMeCN], 848.9
(30) [MꢃꢃHꢃ], 810.9 (50) [Mꢃꢂ
Cl], 707.0 (25)
[Mꢃꢂ H], 671.0 (100) [Mꢃꢂ
PdClꢃ PdCl2ꢃH]. Anal.
ꢁ/1.8 Hz, 4H, C5H4), 4.39 (pt, JHH
ꢁ/1.8 Hz, 4H,
/
/
(b) A. Abe, N. Kimura, S. Tabata, Macromolecules 24 (1991)
6238.
/
/
/
[7] A. Suzuki, J. Organomet. Chem. 652 (2002) 83.
[8] (a) J.G.P. Delis, P.W.N.M. van Leeuwen, K. Vrieze, N. Veldman,
A.L. Spek, J. Fraanje, K. Goubitz, J. Organomet. Chem. 514
(1996) 125;
/
/
/
/
/
/
/
/
/
/
/
(b) I.R. Butler, L.J. Hobson, S.J. Coles, M.B. Hursthouse, K.M.
Abdul Malik, J. Organomet. Chem. 540 (1997) 27;
(c) M. Enders, G. Kohl, H. Pritzkow, J. Organomet. Chem. 622
(2001) 66.
Calc. for C34H44Cl2FeN4Pd2 (883.72): C, 48.14; H, 5.23;
N, 6.60. Found: C, 47.74; H, 5.53; N, 5.56%.
[9] H.P. Dijkstra, M.D. Meijer, J. Patel, R. Kreiter, G.P.M. van
Klink, M. Lutz, A.L. Spek, A.J. Canty, G. van Koten, Organo-
metallics 20 (2001) 3157.
Acknowledgements
[10] K.R. Thomas, J.T. Lin, Y.S. Wen, J. Organomet. Chem. 575
(1999) 301.
We are grateful to the Deutsche Forschungsge-
meinschaft, the Fonds der Chemischen Industrie and
Utrecht University for financial support (research stay
[11] N.J. Long, A.J. Martin, R. Vilar, A.J.P. White, D.J. Williams, M.
Younus, Organometallics 18 (1999) 4261.
[12] J.J. Bishop, A. Davison, M.L. Katcher, D.W. Lichtenberg, R.E.
Merrill, J.C. Smart, J. Organomet. Chem. 27 (1971) 241.
[13] P.K. Byers, A.J. Canty, H. Jin, D. Kruis, B.A. Markies, J.
Boersma, G. van Koten, Inorg. Synth. 32 (1998) 162.
of S.K. in Utrecht). Dr. Bettina Luhmann is acknowl-
¨
edged for the measurement of the ESIꢀ/TOF mass
spectra.
[14] S. Kocher, G.P.M. van Klink, G. van Koten, H. Lang, in press.
¨