Synthesis and characterisation of copper complexes with N-ferrocenoyl-N′-aryl(alkyl)thioureas

Article abstract of DOI:10.1016/S0020-1693(01)00661-2

The treatment of CuCl₂·2H₂O with ferrocenoyl-substituted thioureas of the type Fc-C(O)-NH-C(S)-N′HR (Fc = ferrocenyl; R = C₆H₅; C₆H₄-p-OMe; C₆H₄-p-C(O)Me; C₆

Full text of DOI:10.1016/S0020-1693(01)00661-2

www.elsevier.com/locate/ica
Inorganica Chimica Acta 324 (2001) 309–317
Synthesis and characterisation of copper complexes with
N-ferrocenoyl-N%-aryl(alkyl)thioureas
Yao Feng Yuan a, Ji Tao Wang a, M. Concepcio´n Gimeno b, Antonio Laguna b,*,
Peter G. Jones c
a Department of Chemistry, Nankai Uni6ersity, Tianjin 300071, China
b Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Uni6ersidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
c Institut fu¨r Anorganische und Analytische Chemie, Technische Uni6ersita¨t Braunschweig, Postfach 3329, D-38023 Braunschweig, Germany
Received 11 May 2001; accepted 28 August 2001
Abstract
The treatment of CuCl2·2H2O with ferrocenoyl-substituted thioureas of the type FcꢀC(O)ꢀNHꢀC(S)ꢀN%HR (Fc=ferrocenyl;
R=C6H5; C6H4-p-OMe; C6H4-p-C(O)Me; C6H4-o-Me; C6H4-o-Cl; C6H4-o-NO2; i-Pr) gives the corresponding copper(I) deriva-
tives with the metallic centre in an unusual coordination mode. The complexes were characterised by spectroscopic methods and
X-ray diffraction studies. The electrochemical behaviour of these compounds was also investigated. © 2001 Elsevier Science B.V.
All rights reserved.
Keywords: Copper complexes; Ferrocenyl derivatives; Thioureas; Crystal structures
the keto- or enol-thione form, depending of the ligands
themselves, and the metal ions and counter-anions used
[9–25] (see Table 1).
1. Introduction
It is well known that ferrocene has high electron
density, aromaticity, stability and redox reversibility.
The incorporation of redox-active ferrocene molecules
into transition metal fragments is now opening promis-
ing fields of research [1–4]. Recently our work on
ferrocenyl-substituted acylthiourea derivatives revealed
that, because of the redox reversibility of ferrocene, it
can be used as a probe to investigate the substituent
effects, electron transfer and the interaction between
metal centres by electrochemical methods [5–8].
With the simultaneous presence of S, N and O elec-
tron donors, the versatility and interesting behaviour of
acylthioureas as building blocks in polydentate ligands
for metal ions have become a topic of interest in the
last few years. It has been reported that substituted
acylthiourea ligands might act as monodentate sulfur
donors, bidentate oxygen and sulfur or oxygen and
nitrogen donors. They could also coordinate through
The structures of acylthiourea ligands have a signifi-
cant effect on their resultant coordination chemistry. As
a result of intramolecular hydrogen bonding, the
thiourea N%ꢀH moiety and the amidic O-donor atom
form a six-membered ring, with the consequence that
the ligands coordinate to metal centres in a monoden-
tate fashion through the sulfur donor atom. For exam-
ple, Cernak et al. [12] have prepared the complexes
[CuCl(ptu)2], [CuCl(etu)], [CuCl(btu)2] (ptu: R=
phenyl,
etu:
R=ethyl,
btu:
R=benzyl
in
CH3CHꢁCHC(O)ꢀNHꢀC(S)ꢀNHR), which display this
coordination mode, by the reaction of CuCl2 with the
corresponding derivatives of 2-propenoyl-thiourea.
Furthermore, the ligand, N-benzoyl-N%-n-butylthiourea
(H2L) easily forms mixtures of cis- and trans-
[PtCl2(H2L)2] complexes, in which the ligands bind in a
monodentate fashion to the Pt(II) ion [26].
In contrast, the N%,N%-disubstituted acylthiourea lig-
ands, which do not form an intramolecular hydrogen
bond, tend to coordinate predominantly in a bidentate
(S, O) fashion to the transition metal ions through the
* Corresponding author. Tel.: +34-976-761 185; fax: +34-976-
761 187.
E-mail address: alaguna@posta.unizar.es (A. Laguna).
0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0020-1693(01)00661-2

310
Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
FcꢀC(O)NHꢀC(S)NR1R2. The crystal structure of one
of the complexes in this work shows the N-ferrocenoyl-
N%-aryl(alkyl)thiourea ligand to display an unusual co-
ordination mode to Cu(I). The crystal structures of two
of the ligands are also described.
sulfur and acyl oxygen atoms, e.g. in neutral mononu-
clear complexes [ML%], where M=Ni(II), Cu(II),
2
Mn(II) and Co(III) and the ligands are N-ferrocenoyl-
N%,N%-diethylthiourea [9]. The only notable exceptions
to this mode of coordination of N%N%-disubstituted
acylthiourea ligands can be seen in the complexes of
Ag(I), Hg(II) and Au(I), in which the ligand binds the
metal ion through the S atom only [17].
2. Results and discussion
The coordination chemistry of substituted acylth-
ioureas has led to some interesting practical applica-
tions, including liquid–liquid extraction, pre-concen-
tration and highly efficient chromatographic separa-
tion, fluorimetric detection of the platinum group
metals, and the selective on-line pre-concentration of
ultra-traces of Pd, followed by its determination using
graphite furnace atom absorption spectrometry [24,26].
The preliminary results have shown that the acylth-
iourea ligand could play an important role in the
biological activity of mixed-ligand Pt(II) complexes and
these Pt(II) complexes can thus be used as potential
chemotherapeutic agents [27].
2.1. Synthesis
We have studied the coordination behaviour of the
ferrocenoyl-substituted thioureas FcꢀC(O)ꢀNHꢀC(S)ꢀ
N%HR (R=C6H5 (1); C6H4-p-OMe, (2); C6H4-p-
C(O)Me (3); C6H4-o-Me (4); C6H4-o-Cl (5); C6H4-o-
NO2 (6); i-Pr (7)) with CuCl2·2H2O. These ligands have
been previously described by us and some preliminary
studies provided evidence for intramolecular hydrogen
bonds [28,30]. To confirm this, we have determined the
crystal structure of two of the ligands used here, be-
cause the ligand structure is an important factor in
determining in the coordination mode to the metal
complexes. In both cases intramolecular hydrogen
bonds between the NH and the carbonyl oxygen atom
were observed. The reaction of the ligands with
CuCl2·2H2O at room temperature with alcohol as
As part of our studies on ferrocene-containing substi-
tuted acylthioureas and their transition metal com-
plexes [8], we report here on the synthesis and
characterisation of the complexes formed by the reac-
tion of CuCl2 with ferrocenoyl-thiourea ligands,
Table 1
Some structural features for transition metal complexes of substituted acylthiourea ligands: R1ꢀC(O)ꢀNHꢀC(S)ꢀN%R2R3
No. R1
R2
R3
Central ion
Coordination
atom
Coordination geometry
Reference
1
2
3
4
5
Fc a
Fc
Fc
Et b
Py c
Me d
Ar e
Ph g
Et
H
Me
H
Ni(II)
Fe(II)
Cu(II)
Cu(I)
Cu(I)
O, S
cis-square planar
octahedral
dimer, distorted tetrahedral
planar triangle
dimer, distorted trigonal pyramidal
[9]
[10]
[11]
this work
[12]
O, N%, N¦
S bridge, Cl
S, Cl
S, Cl; Cl or S
bridge
Fc
PE f
H
6
7
8
Ph
Ph
Ph
Et
Et
butyl
Et
propyl
Et
Et
Cu(II)
Ni(II), Pd(II)
O, S
O, S
O, S
O, S
S, (Cl)
O, S
O, (HS)
tetrahedral
cis-square planar
cis-square planar
cis-square planar
cis-square planar
trans-square planar
tetrahedral
octahedral
[13]
[14,15]
[16]
[17]
[18]
[19]
[20]
[21,22]
[23]
[24]
butyl Pt(II)
Et
H
butyl Pt(II)
Et
Et
alkyl
H
9
o-ClꢀPh
Ph
Ni(II)
Pt(II)
10
11
12
13
14
15
NaꢀPh h butyl
Ph
Ph
Ph
Ph
Et
Et
alkyl
Ph
Ag(I)
Ru(III), Rh(III) O, S
Au(I)
Rh(I)
S
linear
O, S,
dinuclear Rh(I), square planar and square-based
N%-tridentate
O, S, Cl
pyramid
dimer
16
Ph
Py i
H
Cu(II)
[25]
a Fc, ferrocenoyl.
b Et, ethyl.
c Py, pyridyl.
d Me, methyl.
e Ar, Aryl.
f PE, propenyl, CH3ꢀCHꢁCHꢀ
g Ph, phenyl
h NaPh, naphthyl
i Py, various substituted pyridine.

Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
311
crystal structure determined for the copper complex 13
and suggests that the sulfur atom of the thiocarbonyl
group is involved in coordination bonding. The stretch-
ing frequencies of NꢀH vibrations either decrease or
form a weak and broad band along with that of N%ꢀH
at approximately 2900–3200 cm−1. The CꢀN stretch-
ing vibration in COꢀNH moiety shifts to higher
wavenumber at 1277 cm−1, as a moderately strong
band. The intensity and wavenumber of w(CꢁO) at 1663
cm−1 are essentially the same as in the free ligands. At
the same time there appear two new absorption bands
at 323 and 384 cm−1 in the far infrared region; the
former is ascribed to w(CuꢀCl) and the latter to
w(CuꢀS) vibration.
Fig. 1. Molecular structure of compound 2 in the crystal showing the
atom numbering scheme.
2.3. NMR spectra
NMR spectra are very useful in determining whether
the coordination reactions of ferrocenoyl-thioureas with
1
Cu(II) chloride have take place. The H and 13C NMR
spectra of the complexes are consistent with the struc-
tural results. The chemical shifts of NꢀH and N%ꢀH
increase by 1.30–2.00 and approximately 0.40 ppm,
respectively, indicating an intermolecular hydrogen
bonding between the NꢀH groups and the chloro atom
coordinated to copper. The resonances for the cy-
clopentadienyl hydrogen atoms of the ferrocenyl group
broaden appreciably; there is a downfield displacement
of about 0.70 ppm for the a protons, whereas the b and
the unsubstituted cyclopentadienyl ring protons are lit-
tle changed. The fact that the resonances for the a
protons of the cyclopentadienyl ring are shifted to
lower field relative to those in the free ligands may be
also be caused by the intramolecular hydrogen bonding
between these protons and the chloro atom coordinated
Fig. 2. The structure of one of the two independent molecules of
compound 6 in the crystal with the atom labelling scheme.
solvent gives the new complexes [CuCl(FcCONHC-
SNHR)2] (R=C6H5 (8); C6H4-p-OMe (9); C6H4-p-
C(O)Me (10); C6H4-o-Me (11); C6H4-o-Cl (12);
C6H4-o-NO2 (13); i-Pr (14)). Elemental analysis, IR
spectra, 1H and 13C NMR spectra and one crystal
structure showed that they form Cu(I) complexes with
an unusual coordination mode, very different from
those reported in other related studies. These results are
also different from those found by us in the reaction of
ferrocenoyl-thioureas without intramolecular hydrogen
bonds, of the type FcꢀC(O)ꢀNHꢀC(S)ꢀNR1R2, in
which N%R1R2ꢁNEt2, N(CH2)5, which with CuCl2 at
room temperature form mononuclear complexes very
quickly. In the resulting Cu(II) complexes the ferro-
cenyl-thioureas act as bidentate ligands to Cu(II) via
the acyl oxygen and sulfur atoms [8].
1
to copper (see X-ray comments below). From their H
NMR data, it can be inferred that the intramolecular
hydrogen bonding is preserved on coordination and is
present also in solution and not only in the solid state.
The 13C NMR spectra of these complexes do not show
significant changes compared with those of the corre-
sponding free ligands.
All the complexes are orange–red or red crystalline
solids. They are soluble in DMF, DMSO, CH2Cl2 and
CHCl3, slightly soluble in EtOH, Me2CO and Et2O, but
insoluble in non-polar solvents such as pentane and
2.4. Crystal structure determinations
1
benzene. Their elemental analysis, IR spectra and H
and 13C NMR spectra data are reported in Section 4.
The previous investigations of the ferrocenoyl-
thiourea ligands indicated intramolecular hydrogen
bonds between carbonyl and N%ꢀH groups in acyl-
thiourea side chains [28,29]. We have established by
X-ray diffraction studies the crystal structures of the
ligands 2 and 6; the molecules can be seen in Figs. 1
and 2, respectively. A selection of bond lengths and
angles is collected in Tables 2 and 3, respectively.
In the structure of the ferrocenoyl-thiourea derivative
FcꢀC(O)ꢀNHꢀC(S)ꢀNHꢀC6H4-p-OꢀMe (2) the overall
bond lengths and angles in the ferrocene and the
2.2. Infrared spectra
The infrared spectra of the complexes show the fol-
lowing significant changes when compared with the
spectra of the corresponding ligands. The most striking
changes are observed for the CꢁS stretching frequency
at approximately 1343 cm−1 in the free ligands, which
disappears completely, or shifts to lower wavenumber
and decreases in intensity. This is in agreement with the

312
Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
thiourea moiety are normal, with a C(12)ꢀS bond dis-
,
tance of 1.6740(17) A and C(11)ꢀO(1) distance of
,
1.222(5) A, both typical of double bonds. The unit
ꢀN%HꢀC(S)ꢀNHꢀC(O)ꢀ forms an intramolecular hydro-
gen bond N(2)ꢀH(02)···O(1) (H···O 1.999(16) A) to give
,
a planar six-membered ring, which is almost parallel to
the cyclopentadienyl ring of the ferrocene moiety. The
same hydrogen atom acts as a weak intermolecular H
bond donor to the methoxy oxygen atom, with
,
H(02)···O(2) 2.507(18) A, thus forming a highly asym-
metric three-centre H bonding system. Finally, there is
a non-classical H bond from a proton of the cyclopen-
,
tadienyl ring, C(2)ꢀH(2)···O(1) with H···O 2.55 A.
The structure of FcꢀC(O)ꢀNHꢀC(S)ꢀNHꢀC6H4-o-
NO2 (6) can be seen in Fig. 2, it crystallises with two
independent molecules. In both molecules, the group
N(2)ꢀH(03) acts as donor for an intramolecular three-
centre H bond to O(1) and O(2), with H···O(1)
Fig. 3. The structure of complex 13 in the crystal showing the atom
numbering scheme.
Weak intermolecular
H bonds are formed from
,
1.972(18), 2.00(2) and H···O(2) 2.281(19), 2.31(2) A.
N(1)ꢀH(02) to the thiourea sulfur, with H···S 2.84(2),
,
2.78(2) A. There are also several intermolecular hydro-
Table 2
gen bonds of the type CꢀH···O, of which the shortest
,
Selected bond lengths (A) and angles (°) for compound 2
,
,
are H(16)···O(1%) 2.38 A and H(3)···O(2%) 2.45 A.
Bond lengths
The structure of complex 13 has been established by
X-ray diffraction and the molecule is shown in Fig. 3.
A selection of bond lengths and angles is collected in
Table 4. The Cu(I) atom is three-coordinated by the
sulfur atoms of two different ligands and by one chlo-
rine atom. This result is different from that found for
the disubstituted ferrocenoyl-thioureas, where a four-
coordinated copper derivative was found [9], and also
for the Cu(I) complex with phenylthiourea, in which
SꢀC(12)
1.6740(17)
1.225(2)
1.3706(19)
1.427(2)
N(1)ꢀC(12)
N(2)ꢀC(12)
N(2)ꢀC(13)
C(1)ꢀC(11)
1.392(2)
1.326(2)
1.430(2)
1.474(2)
O(1)ꢀC(11)
O(2)ꢀC(16)
O(2)ꢀC(19)
N(1)ꢀC(11)
1.383(2)
Bond angles
O(1)ꢀC(11)ꢀN(1) 122.53(15)
O(1)ꢀC(11)ꢀC(1) 122.42(15)
N(1)ꢀC(11)ꢀC(1) 115.04(15)
N(2)ꢀC(12)ꢀN(1) 116.71(15)
N(1)ꢀC(12)ꢀS
118.16(13)
C(18)ꢀC(13)ꢀN(2) 119.16(15)
C(14)ꢀC(13)ꢀN(2) 120.81(15)
O(2)ꢀC(16)ꢀC(17) 123.97(15)
O(2)ꢀC(16)ꢀC(15) 116.00(15)
N(2)ꢀC(12)ꢀS
125.10(13)
Table 4
,
Selected bond lengths (A) and angles (°) for complex 13
Table 3
Bond lengths
CuꢀCl(1)
CuꢀS
CuꢀS%
SꢀC(12)
O(1)ꢀC(11)
N(1)ꢀC(12)
N(1)ꢀC(11)
N(2)ꢀC(12)
N(2)ꢀC(13)
,
Selected bond lengths (A) and angles (°) for compound 6
2.1876(6) C(1)ꢀC(11)
2.2007(7) S%ꢀC(12%)
2.2057(6) O(1%)ꢀC(11%)
1.464(3)
1.702(2)
1.224(3)
1.372(3)
1.401(3)
1.326(3)
1.421(3)
1.465(3)
Bond lengths
SꢀC(12)
1.6661(15) S%ꢀC(12%)
1.6636(15)
1.2322(19)
1.3830(19)
1.3836(19)
1.339(2)
1.699(2)
1.219(3)
1.372(3)
1.408(3)
1.319(3)
1.428(3)
N(1%)ꢀC(12%)
N(1%)ꢀC(11%)
N(2%)ꢀC(12%)
N(2%)ꢀC(13%)
C(1%)ꢀC(11%)
O(1)ꢀC(11)
N(1)ꢀC(12)
N(1)ꢀC(11)
N(2)ꢀC(12)
N(2)ꢀC(13)
C(1)ꢀC(11)
1.2277(18) O(1%)ꢀC(11%)
1.3860(19) N(1%)ꢀC(11%)
1.3882(19) N(1%)ꢀC(12%)
1.341(2)
1.4126(19) N(2%)ꢀC(13%)
1.468(2) C(1%)ꢀC(11%)
N(2%)ꢀC(12%)
1.4140(19)
1.467(2)
Bond angles
Cl(1)ꢀCuꢀS
Cl(1)ꢀCuꢀS%
SꢀCuꢀS%
C(12)ꢀSꢀCu
C(12)ꢀN(1)ꢀC(11) 126.0(2)
C(5)ꢀC(1)ꢀC(11)
C(2)ꢀC(1)ꢀC(11)
O(1)ꢀC(11)ꢀN(1)
O(1)ꢀC(11)ꢀC(1)
N(1)ꢀC(11)ꢀC(1)
N(2)ꢀC(12)ꢀN(1)
N(2)ꢀC(12)ꢀS
Bond angles
128.63(3) N(1)ꢀC(12)ꢀS
122.98(3) C(18)ꢀC(13)ꢀN(2)
108.37(2) C(12%)ꢀS%ꢀCu
122.19(18)
119.6(2)
114.23(8)
C(12)ꢀN(1)ꢀC(11) 129.20(14) C(11%)ꢀN(1%)ꢀC(12%) 128.73(14)
C(12)ꢀN(2)ꢀC(13) 124.66(13) C(12%)ꢀN(2%)ꢀC(13%) 124.89(13)
C(5)ꢀC(1)ꢀC(11)
C(2)ꢀC(1)ꢀC(11)
O(1)ꢀC(11)ꢀN(1)
O(1)ꢀC(11)ꢀC(1)
N(1)ꢀC(11)ꢀC(1)
N(2)ꢀC(12)ꢀN(1)
N(2)ꢀC(12)ꢀS
124.52(14) C(2%)ꢀC(1%)ꢀC(11%)
127.30(14) C(5%)ꢀC(1%)ꢀC(11%)
122.77(14) O(1%)ꢀC(11%)ꢀN(1%)
123.46(13) O(1%)ꢀC(11%)ꢀC(1%)
113.77(13) N(1%)ꢀC(11%)ꢀC(1%)
114.74(13) N(2%)ꢀC(12%)ꢀN(1%)
126.50(12) N(2%)ꢀC(12%)ꢀS%
118.71(12) N(1%)ꢀC(12%)ꢀS%
128.37(13)
123.14(14)
122.51(14)
122.64(13)
114.82(13)
115.26(13)
126.10(12)
118.59(12)
113.52(8) C(12%)ꢀN(1%)ꢀC(11%) 125.8(2)
C(2%)ꢀC(1%)ꢀC(11%)
C(5%)ꢀC(1%)ꢀC(11%)
O(1%)ꢀC(11%)ꢀN(1%)
O(1%)ꢀC(11%)ꢀC(1%)
N(1%)ꢀC(11%)ꢀC(1%)
N(2%)ꢀC(12%)ꢀN(1%)
N(2%)ꢀC(12%)ꢀS%
122.8(2)
129.4(2)
121.1(2)
121.7(2)
117.2(2)
117.9(2)
119.06(17)
123.06(17)
130.5(2)
121.5(2)
121.1(2)
122.6(2)
116.3(2)
117.8(2)
N(1)ꢀC(12)ꢀS
C(14)ꢀC(13)ꢀN(2) 122.36(15) C(14%)ꢀC(13%)ꢀN(2%) 122.82(15)
C(18)ꢀC(13)ꢀN(2) 119.53(16) C(18%)ꢀC(13%)ꢀN(2%) 119.45(15)
119.98(17) N(1%)ꢀC(12%)ꢀS%

Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
313
there are two centrosymmetric dimeric molecules with
experimentally determined anodic and cathodic peak
current are given in Table 5. For comparison, the result
of parent compound ferrocene is listed in the same
table.
tetracoordinated Cu(I) atoms [12]. The CuꢀS bond
,
distances are 2.2007(7) and 2.2057(6) A, and as expected
are shorter than those found in the above-mentioned
tetra-coordinate complexes. The CꢀS distances, 1.699(2)
It can be seen from Table 5 that all the compounds
exhibit one pair of redox peaks, corresponding to the
Fe(II)/Fe(III) system. The electrochemical parameters
indicate the chemical reversibility of the redox process,
e.g. the ipc/ipa ratio is close to unity and the peak
potential separation DEp is in the range 50–90 mV.
The Eo% values of the redox peaks in the ligands and
their complexes are anodically shifted with respect to
that of ferrocene (0.43 V), indicating that the acyl-
thiourea groups exert predominately electron-withdraw-
ing inducing effects, rendering oxidation more difficult.
All the complexes exhibit one reversible wave, which
demonstrates that the two ferrocenyl fragments within
ferrocenoyl-thiourea–copper complexes are electro-
chemically equivalent, simultaneously oxidised with no
mutual interaction. However, no peaks corresponding
to the oxidation process of the Cu(I)/Cu(II) couple are
observed for the complexes in the scan potential range
,
and 1.702(2) A, are longer than in the free ligand. The
CuꢀCl bond length is 2.1876(6), again shorter than in
the other copper-thiourea derivatives. The angles
around the copper atom are slightly distorted from an
ideal trigonal planar geometry, noticeably the narrow
SꢀCuꢀS angle of 108.37(2)°. This may be associated
with the presence of intramolecular hydrogen bonds
between the N(1)ꢀH(01) and N(1%)ꢀH(01%) groups and
,
the chlorine atom of 2.92(2) and 2.67(2) A, respectively
,
,
(normalised to NꢀH 1.009 A: 2.63 and 2.48 A [31]) with
angles of acceptable linearity 167(2) and 169(2)°. The
cyclopentadiene hydrogens H5 and H5% also make short
,
contacts of 2.70 and 2.86 A to the chlorine atom, which
could be regarded as non-classical H bonds. There are
further intramolecular hydrogen bonding systems in-
volving the ꢀN%HꢀC(S)ꢀNHꢀC(O)ꢀ unit, forming two
six-membered rings with distances for N(2)ꢀH(02)···
O(1) and N(2%)ꢀH(02%)···O(1%) of 1.95(3) and 1.94(3) A,
from 0 to 1.0 V and with scan rate 100 mV s−1
.
,
respectively.
It seems that the nature of the substituent groups R
in the FcꢀC(O)ꢀNHꢀC(S)ꢀN%HR has a weak influence
on the electrochemical properties of these ligands, i.e.
0.79 V (R=o-ClC6H4, C6H5), 0.78 V (o-CH3C6H4,
p-OCH3C6H4) and 0.77 V (o-NO2C6H4, i-Pr). How-
ever, we note that the substituent groups R have more
influence on the redox behaviour of the ferrocenyl
groups in these complexes, 0.75 V (R=o-NO2C6H4),
\0.74 V (o-ClC6H4), \0.72 V (C6H5, p-OCH3C6H4,
o-CH3C6H4), \0.69 V (i-Pr), which seems to show
that the electronic effects of the substituents R on N%
can be delivered to the redox centre through the system
2.5. Cyclic 6oltammetric data
The cyclic voltammetric behaviour of the ligands and
their copper complexes has been studied using CH2Cl2
as solvent. Attention was essentially centred on the
ferrocene/ferrocenium redox couple in the ligands and
their complexes. The anodic (Epa) and cathodic (Epc)
peak potentials, the formal reduction potential Eo%=
0.5(Epa+Epc), the separation (DEp) between the anodic
and cathodic peak potentials and the ratio ipc/ipa of the
Table 5
Electrochemical data for the ligands and their copper complexes (V vs. SCE)
a
b
Compound
mV s−1
Epa (V)
Epc (V)
Eo%(V)
DEp (mV)
ipc/ipa
Ferrocene
1 FcCONHCSNHC6H5
100
100
100
100
100
100
100
100
100
100
100
100
100
0.47
0.82
0.81
0.82
0.83
0.81
0.81
0.75
0.76
0.75
0.78
0.77
0.72
0.39
0.75
0.74
0.74
0.74
0.73
0.73
0.69
0.68
0.69
0.70
0.72
0.66
0.43
0.79
0.78
0.78
0.79
0.77
0.77
0.72
0.72
0.72
0.74
0.75
0.69
80
70
70
80
90
80
80
60
80
60
80
50
60
1.06
1.03
1.04
1.02
1.04
1.07
1.10
1.05
0.97
1.01
1.04
1.07
0.90
2 FcCONHCSNHC6H4-p-OMe
4 FcCONHCSNHC6H4-o-Me
5 FcCONHCSNHC6H4-o-Cl
6 FcCONHCSNHC6H4-o-NO2
7 FcCONHCSNH-i-Pr
8 [CuCl(FcCONHCSNHC6H5)2]
9 [CuCl(FcCONHCSNHC6H4-p-OMe)2]
11 [CuCl(FcCONHCSNHC6H4-o-Me)2]
12 [CuCl(FcCONHCSNHC6H4-o-Cl)2]
13 [CuCl(FcCONHCSNHC6H4-o-NO2)2]
14 [CuCl(FcCONHCSNH-i-Pr)2]
a The redox potential values Eo%is formal reduction potential for a reversible couple and is defined by Eo%=0.5(Epa+Epc).
b The reversibility of the oxidation wave implies DEp=Epa−Epc:60 mV at 25 °C and ipc/ipa:1, slow electron transfer at the electrode
surface, ‘irreversibility’, cause the peak separation (DEp) to increase.

314
Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
of the |-bonds and the intramolecular hydrogen bond-
ing plane. These potential values are significantly lower
than that of the free ligands, thus suggesting that the
two ferrocene fragments in the complexes are easier to
oxidise.
at r.t. (2993 °C). The voltammograms were scanned
over the potential range 0–1.0 V (positive potential
direction in forward mode), and the scan rates em-
ployed were 100 mV s−1
.
4.2. Synthesis of the ligands
3. Conclusion
The N-ferrocenoyl-N%-aryl(alkyl) thioureas were pre-
pared according to literature methods [6,30].
N-Ferrocenoyl-N%-aryl(alkyl)thiourea ligands act as
unidentate ligands through the sulfur atom, forming
strong complexes with the metal centre Cu(I). The
coordination chemistry of N-ferrocenoyl-N%-aryl-
(alkyl)thiourea ligands (H2L) is dominated by a strong
intramolecular hydrogen bond which locks the thiourea
N%ꢀH moiety and amidic O-donor atom into a six-
membered ring, with the consequence that the ligand
coordinates to the Cu(I) ion through the S atom only,
yielding [Cu(H2L)2Cl] complexes. The Cu(II) was re-
duced to Cu(I) during the coordination process with
oxidation of the ligand. A plausible explanation is that
the higher affinity of the sulfur atom to Cu(I) evidently
plays a certain role. At the same time, intramolecular
hydrogen bonds of the type NH···Cl type may be
assumed to contribute to the stabilisation of the Cu(I)
complexes.
4.3. Synthesis of the complexes
4.3.1. [CuCl(FcCONHCSNHC6H5)2] (8)
To a solution of 1 (0.364 g, 1 mmol) in C2H5OH (50
ml) was added dropwise CuCl2·2H2O (0.0852 g, 0.5
mmol) in C2H5OH (20 ml). The reaction mixture was
stirred for 8 h at r.t. The resulting orange–red precipi-
tate was washed successively with C2H5OH, diethyl
ether and petroleum ether (30–60 °C) prior to drying
in vacuo. Compound 8 was obtained as orange–red
crystals. Yield: 82%. m.p.: 164–167 °C dec. Elemental
analysis, Found: C, 51.78; H, 3.89; N, 6.59. Calc. for
C36H32ClCuFe2N4O2S2: C, 52.25; H, 3.91; N, 6.77%.
1
NMR data; H NMR (CDCl3): 4.35 (s, 5H, C5H5), 4.57
(s, 2H, H3, H4ꢀC5H4), 5.44 (s, 2H, H2, H5ꢀC5H4), 7.30,
7.37, 7.45 (m, 5H, ꢀC6H4), 10.51 (s, 1H, ꢀNH), 13.04 (s,
1H, ꢀN%H). 13C NMR: 178.02 [ꢀC(S)ꢀ], 175.0 [ꢀC(O)ꢀ],
136.70, 129.15, 127.83, 125.65 (ꢀC6H5), 71.49 (C1 of
C5H4), 70.64 (C5H5), 70.57 (C3,4 of C5H4), 72.99 (C2,5 of
C5H4). IR (KBr pellets, cm−1): w(NꢀH) and w(N%ꢀH)
2900–3230 (w, br), ferrocenyl group: 3090 (w), 1376
(w), 1105 (m), 1000 (m), 908 (w), 826 (m), 498 (m),
w(CꢁO) 1663 (s), l(CNH) 1507 (vs), w(CꢀN)
[ꢀNꢀC(S)ꢀN] 1154 (m), w(CꢀN) [ꢀC(O)ꢀNH] 1278 (m),
w(CꢁS) 1343 (w).
4. Experimental
4.1. General
Infrared spectra were recorded in the range 4000–400
cm−1 on a Nicolet FT-IR 170 SX spectrometer with
KBr pellets. Far-IR measurements were made with a
Nicolet FT-IR 170 SX spectrophotometer by using
Nujol mulls in the 100–500 cm−1 region.
The synthesis of complexes 9–14 proceeds in a simi-
lar manner to compound 8; thus only the spectroscopic
data will be given.
1
All H and 13C NMR spectra were recorded on a
Varian Unity 300 spectrometer, using CDCl3 as solvent
and TMS as internal standard. Mass spectra were
recorded on a VG Autospec, with the FAB technique,
using nitrobenzyl alcohol as matrix. Elemental analyses
were carried out on a Perkin–Elmer 240C analyser.
Melting points were determined on a PHMK (from
Germany) melting point apparatus and were uncor-
rected. Cyclic voltammetric experiments were per-
4.3.2. [CuCl(FcCONHCSNHC6H4ꢀOMe)2] (9)
Color: orange–red. Yield: 76%, 0.336 g. m.p.: 167–
172 °C dec. Recystallisation from a CHCl3–petroleum
ether (90–120 °C) solution gave X-ray quality crystals.
Elemental analysis, Found: C, 51.34; H, 4.15; N, 6.41.
Calc. for C38H36Fe2ClCuN4O4S2: C, 51.42; H, 4.10; N,
6.31%. NMR data; 1H NMR (CDCl3): 4.36 (s, 5H,
C5H5), 4.58 (s, 2H, H3, H4ꢀC5H4), 5.44 (s, 2H, H2,
H5ꢀC5H4), 3.80 (s, 3H, ꢀOMe), 6.88, 6.91 (d, 2H,
ꢀC6H4), 7.34, 7.37 (d, 2H, ꢀC6H4), 10.52 (s, 1H, ꢀNH),
12.84 (s, 1H, ꢀN%H). 13C NMR: 178.80 [ꢀC(S)ꢀ], 174.83
[ꢀC(O)ꢀ], 158.94, 129.64, 127.01, 114.28 (ꢀC6H4), 71.70
(C1 of C5H4), 70.59 (C5H5), 70.53 (C3,4 of C5H4ꢀ), 72.89
(C2,5 of C5H4), 55.41 (ꢀOMe). IR (KBr pellets, cm−1):
w(NꢀH) 3213.7 (w), w(NꢀH) 2960–3082 (w, br), ferro-
cenyl group: 3082 (w), 1376 (w), 1105 (m), 1031 (m),
900 (w), 834 (m), 482 (m), w(CꢁO) 1663 (s), l(CNH)
formed on
a BAS-100B electrochemical analyser
(Purdue Research Park, West Lafayette, Indiana, USA)
equipped with a three electrode assembly with 0.1
mol−1 n-Bu4NPF6 as supporting electrolyte and
CH2Cl2 as solvent. The working electrode was a plat-
inum disk of 1.5 mm in diameter embedded in a cobalt
glass seal and was polished consecutively with polishing
alumina and diamond suspensions between runs. The
reference electrode was a KCl saturated and blanketed
with N2 before the first scan. Measurements were made

Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
315
1507 (vs), l(CNH) 1507 (vs), w(CꢀN) [ꢀNꢀC(S)ꢀN]
1146 (vs), w(CꢀN) [ꢀC(O)ꢀNH] 1277 (m), w(CꢁS) 1304
(w). MS(FAB+), m/z (%)=852 (12) [M−Cl]+.
w(CꢀN) [ꢀNꢀC(S)ꢀN] 1162 (m), w(CꢀN) [ꢀC(O)ꢀNH]
1269 (m), w(CꢁS) 1318 (w).
4.3.6. [CuCl(FcCONHCSNHC6H4-o-NO2)2] (13)
Color: orange–red. Yield: 81%. m.p.: 142–144 °C
dec. Crystals suitable for X-ray diffraction studies were
obtained from CHCl3–petroleum ether solution (90–
120 °C). Elemental analysis, Found: C, 46.89; H, 3.32;
N, 9.23. Calc. for C36H30ClCuFe2N6O6S2: C, 47.12; H,
4.3.3. [CuCl(FcCONHCSNHC6H4-p-C(O)CH3)2] (10)
Color: orange–red. Yield: 79%. m.p.: 171–172 °C
dec. Elemental analysis, Found: C, 52.93; H, 4.05; N,
5.94. Calc. for C40H36ClCuFe2N4O4S2: C, 52.70; H,
1
4.00; N, 6.15%. NMR data; H NMR (CDCl3): 4.36 (s,
1
5H, C5H5), 4.60 (m, 2H, H3, H4ꢀC5H4), 5.43 (m, 2H,
H2, H5ꢀC5H4), 2.57 [s, 3H, ꢀC(O)ꢀMe], 7.66, 7.69 (d,
2H, ꢀC6H4), 7.95, 7.98 (d, 2H, ꢀC6H4), 10.54 (s, 1H,
ꢀNH), 13.30 (s, 1H, ꢀN%H). 13C NMR: 197.05 [ꢀC(S)ꢀ],
178.39, 174.93 [ꢀC(O)ꢀ], 140.92, 135.59, 129.34, 124.85
(ꢀC6H4), 71.35 (C1 of C5H4), 70.66 (C5H5), 70.44 (C3,4
of C5H4), 73.15 (C2,5 of C5H4), 26.52 (Me). IR (KBr
pellets, cm−1): w(NꢀH) and w(N%ꢀH) 2900–3255 (w,
br), ferrocenyl group: 3091 (w), 1376 (w), 1105 (m),
1009 (m), 909 (w), 843 (m), 498 (m), w(CꢁO) 1680 (s),
l(CNH) 1507 (vs), w(CꢀN) [ꢀNꢀC(S)ꢀN] 1155 (m),
w(CꢀN) [ꢀC(O)ꢀNH] 1269 (vs), w(CꢁS) 1335 (w).
3.30; N, 9.16%. NMR data; H NMR (CDCl3): 4.34 (s,
5H, C5H5), 4.58 (m, 2H, H3, H4ꢀC5H4), 5.22 (m, 2H,
H2, H5ꢀC5H4), 7.3–8.2 (m, 4H, ꢀC6H4), 9.94 (s, 1H,
ꢀNH), 13.49 (s, 1H, ꢀN%H). 13C NMR: 179.57 [ꢀC(S)ꢀ],
172.93 [ꢀC(O)ꢀ], 142.97, 133.62, 132.01, 129.20, 127.49,
125.35 (ꢀC6H5), 71.52 (C1 of C5H4), 70.63 (C5H5), 69.82
(C3,4 of C5H4), 73.03 (C2,5 of C5H4). IR (KBr pellets,
cm−1): w(NꢀH) and w(N%ꢀH) 2640–3189 (w, br), ferro-
cenyl group: 3082 (w), 1376 (w), 1105 (m), 1031 (m),
916 (w), 818 (m), 490 (m), w(CꢁO) 1655 (s), l(CNH)
1507 (vs), w(CꢀN) [ꢀNꢀC(S)ꢀN] 1163 (m), w(CꢀN)
[ꢀC(O)ꢀNH] 1277 (m), w(CꢁS) 1343 (w).
4.3.7. [CuCl(FcCONHCSNH-i-C3H7)2] (14)
4.3.4. [CuCl(FcCONHCSNHC6H4-o-Me)2] (11)
Color: orange–red. Yield: 64%. m.p.: 178–179 °C
dec. Elemental analysis, Found: C, 47.34; H, 4.50; N,
7.07. Calc. for C30H36ClCuFe2N4O2S2: C, 47.44; H,
Color: orange–red. Yield: 76%. m.p.: 167–172 °C
dec. Elemental analysis, Found: C, 53.11; H, 4.28; N,
6.95. Calc. for C38H36ClCuFe2N4O2S2: C, 53.34; H,
1
4.79; N, 7.38%. NMR data; H NMR (CDCl3): 4.30 (s,
1
4.25; N, 6.55%. NMR data; H NMR (CDCl3): 4.41 (s,
5H, C5H5), 4.48 (m, 2H, H3, H4ꢀC5H4), 5.27 (m, 2H,
H2, H5ꢀC5H4), 1.28 (s, 7H, i-C3H7), 10.02 (s, 1H, ꢀNH),
11.04 (s, 1H, ꢀN%H). 13C NMR: 177.38 [ꢀC(S)ꢀ], 173.96
[ꢀC(O)ꢀ], 72.14 (C1 of C5H4), 70.41 (C5H5), 69.97 (C3,4
of C5H4), 72.50 (C2,5 of C5H4), 47.55 (ꢀCHꢀ), 21.67
(ꢀCH3). IR (KBr pellets, cm−1): w(NꢀH) and w(N%ꢀH)
3262–3156 (w, br), ferrocenyl group: 3082 (w), 1376
(w), 1100 (m), 999 (m), 917 (w), 826 (m), 490 (m),
w(CꢁO) 1663 (s), l(CNH) 1515 (vs), w(CꢀN)
[ꢀNꢀC(S)ꢀN] 1146 (m), w(CꢀN) [ꢀC(O)ꢀNH] 1277 (m),
w(CꢁS) 1352 (w).
5H, C5H5), 4.62 (m, 2H, H3, H4ꢀC5H4), 5.43 (m, 2H,
H2, H5ꢀC5H4), 2.31 [s, 3H, ꢀMe], 7.54 (s, 1H, ꢀC6H4),
7.27 (s, 3H, ꢀC6H4), 10.44 (s, 1H, ꢀNH), 12.61 (s, 1H,
ꢀN%H). 13C NMR: 179.40 [ꢀC(S)ꢀ], 174.2 [ꢀC(O)ꢀ],
135.93, 133.90, 130.87, 128.07, 126.92, 126.55 (ꢀC6H5),
71.83 (C1 of C5H4), 70.57 (C5H5), 70.22 (C3,4 of C5H4),
72.81 (C2,5 of C5H4), 17.84 (ꢀCH3). IR (KBr pellets,
cm−1): w(NꢀH) and w(N%ꢀH) 3189–3074 (w, br), ferro-
cenyl group: 3073 (w), 1376 (w), 1105 (m), 1023 (m),
909 (w), 818 (m), 490 (m), w(CꢁO) 1655 (s), l(CNH)
1523 (vs), w(CꢀN) [ꢀNꢀC(S)ꢀN] 1163 (m), w(CꢀN)
[ꢀC(O)ꢀNH] 1269 (m), w(CꢁS) 1343 (w). MS(FAB+),
m/z (%)=820 (22) [M−Cl]+.
4.4. Crystallography
The crystals were mounted in inert oil on a glass fibre
and transferred to the cold gas stream of the diffrac-
tometer (2: Siemens P4, −100 °C; 6, 13: Bruker
SMART 1000 CCD, −130 °C). Data were collected
using monochromated Mo Ka diffractometer (u=
0.71073). An absorption correction was applied for 2
on the basis of c-scans, for 6 on the basis of multiple
scans with the program SADABS and for 13 by numeri-
cal methods following face-indexing. The structures
were solved by direct methods and refined on F2 using
the program SHELXL-97 [32]. All non-hydrogen atoms
were refined anisotropically. Hydrogen atoms of the
NH groups were refined freely, methyls as rigid groups
and other H atoms using a riding model. The absolute
structure of 2 was determined by the Flack parameter
4.3.5. [CuCl(FcCONHCSNHC6H4-o-Cl)2] (12)
Color: orange–red. Yield: 79%. m.p.: 180–181 °C
dec. Elemental analysis, Found: C, 48.54; H, 3.31; N,
6.34. Calc. for C36H30Fe2N4O2S2CuCl3: C, 48.23; H,
1
3.38; N, 6.25%. NMR data; H NMR (CDCl3): 4.35 (s,
5H, C5H5), 4.59 (m, 2H, H3, H4ꢀC5H4), 5.43 (m, 2H,
H2, H5ꢀC5H4), 7.41–7.35 (m, 4H, ꢀC6H4), 10.53 (s, 1H,
ꢀNH), 13.07 (s, 1H, ꢀN%H). 13C NMR: 178.64 [ꢀC(S)ꢀ],
175.01 [ꢀC(O)ꢀ], 135.20, 133.36, 129.31, 126.88
(ꢀC6H5), 71.35 (C1 of C5H4), 70.61 (C5H5), 70.55 (C3,4
of C5H4), 73.06 (C2,5 of C5H4). IR (KBr pellets, cm−1):
w(NꢀH) and w(N%ꢀH) 3189–3000 (w, br), ferrocenyl
group: 3074 (w), 1376 (w), 1113 (m), 1006 (m), 909 (w),
818 (m), 490 (m), w(CꢁO) 1655 (s), l(CNH) 1515 (vs),

316
Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
Table 6
Details of data collection and structure refinement for the compounds 2, 6 and 13
Compound
2
6
13·CHCl3
Chemical formula
Crystal habit
T (°C)
C19H18FeN2O2S
red prism
−100
C18H15FeN3O3S
red plate
−130
C37H31Cl4CuFeN6O6S2
red plate
−130
,
u (A)
0.71073
tetragonal
0.71073
monoclinic
P21/n
0.71073
triclinic
Crystal system
Space group
(
(
P421c
P1
Unit cell dimensions
,
a (A)
19.0602(12)
19.0602(12)
9.7138(14)
90
90
90
3528.9(6)
8
21.9441(16)
6.9820(9)
22.0803(18)
90
95.237(3)
90
3368.9(6)
8
1.614
11.0605(10)
11.8267(10)
15.7000(14)
85.131(3)
79.420(3)
85.310(3)
2006.9(3)
2
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
U (A )
Z
Dcalc (g cm−3
M
F(000)
)
1.484
394.26
1632
1.716
1036.84
1048
409.24
1680
Crystal size (mm)
2qmax. (°)
0.60×0.40×0.30
55
9.9
0.734–0.830
8448
4049
0.020
0.0225
0.0509
236
0.42×0.33×0.07
56.5
10.4
0.677–0.928
36 598
8379
0.20×0.15×0.03
56.5
16.6
0.730–0.953
27 956
9928
0.048
0.0348
0.0818
552
v(Mo Ka) (cm−1
Transmission
)
Reflections measured
Unique reflections
Rint
0.040
R
a(F\4|(F))
0.0293
0.0776
485
wR b(F2, all reflections)
Parameters
Restraints
S
Max. Dz (e A
2
1.00
0.17
0
1.01
0.41
348
0.95
0.84
c
−3
,
)
a R(F)=ꢀ ꢁꢁFoꢁ−ꢁFcꢂ/ꢀ ꢁFoꢁ.
b wR(F2)=[ꢀ {w(Fo2−Fc2)2}/ꢀ {w(Fo2)2}]0.5; w−1=|2(Fo2)+(aP)2+bP, where P=[Fo2+2Fc2]/3 and a and b are constants adjusted by the
program.
c S=[ꢀ {w(Fo2−Fc2)2}/(n−p)]0.5, where n is the number of data and p is the number of parameters.
Acknowledgements
x=0.011(11). The chloroform of solvation of com-
pound 13 is disordered over two positions. To improve
stability of refinement, weak U value restraints were
employed (SIMU). Further crystal data are given in
Table 6.
We thank the National Natural Science Foundation
of China (Grant No. 298702018), the Direccio´n Gen-
eral de Ensen˜anza Superior (No. PB97-1010-C02-01)
and the Fonds der Chemischen Industrie for financial
support.
5. Supplementary material
References
Crystallographic data (excluding structure factors)
for the structural analysis have been deposited with the
Cambridge Crystallographic Data Centre, CCDC No.
157407-9 for compounds 2, 6 and 13. Copies of this
information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (fax: +44-1223-336-033; e-mail: deposit@
ccdc.cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
[1] A. Togni, T. Hayashi (Eds.), Ferrocenes: Homogeneus Catalysis,
Organic Synthesis, Material Science, VCH, Weinheim, Germany,
1995 and references cited therein.
[2] N.J. Long, Metallocenes. An Introduction to Sandwich Com-
plexes, Blackwell Science, Oxford, 1998.
[3] A. Togni, R.L. Halterman (Eds.), Metallocenes. Synthesis, Reac-
tivity, Applications, Wiley-VCH, Weinheim, 1998.
[4] (a) M.C. Gimeno, A. Laguna, Gold Bull. 32 (1999) 90;

Y.F. Yuan et al. / Inorganica Chimica Acta 324 (2001) 309–317
317
(b) R.J. Less, J.L. Wicks, N.P. Chatterton, M.J. Dewey, N.L.
Cromhout, M.A. Halcrow, J.E. Davies, J. Chem. Soc., Dalton
Trans. (1996) 4055;
(c) M.D. Ward, Chem. Soc. Rev. 24 (1995) 121;
(d) A. Benito, J. Cano, R. Martinez-Manez, J. Soto, J. Paya, F.
Lloret, M. Julve, J. Faus, M.D. Marcos, Inorg. Chem. 32 (1993)
1197;
(e) M.J.L. Tendero, A. Benito, J. Cano, J.M. Lloris, R. Mar-
tinez-Manez, J. Soto, A.J. Edwards, P.R. Raithby, M.A. Rennie,
J. Chem. Soc., Chem. Commun. (1995) 1643;
[15] P. Knuuttilla, H. Knuuttilla, H. Hennig, L. Beyer, Acta Chem.
Scand. Ser. A 36 (1982) 541.
[16] A. Irving, K.R. Koch, M. Matoetoe, Inorg. Chim. Acta 206
(1993) 193.
[17] R.A. Bailey, K.L. Rothaupt, R.K. Kullnig, Inorg. Chim. Acta
147 (1988) 233.
[18] S. Bourne, K.R. Koch, J. Chem. Soc., Dalton Trans. (1993)
2071.
[19] K.R. Koch, J.D. Toit, M.R. Caira, J. Chem. Soc., Dalton Trans.
(1994) 785 and references therein.
(f) N. Chabert-Couchouron, C. Marzin, G. Tarrago, N. J.
Chem. 21 (1997) 355;
[20] U. Braun, R. Richter, J. Sieler, A.I. Yanovski, Y.T. Struchkov,
Z. Anorg. Allg. Chem. 529 (1985) 201.
(g) T. Kawamoto, Y. Kushi, J. Chem. Soc., Dalton Trans. (1992)
3137.
[21] J. Sieler, R. Richter, E. Hoyer, Z. Anorg. Allg. Chem. 580 (1990)
167.
[5] J.T. Wang, Y.M. Xu, Y.F. Yuan, B. Wang, Y.A. Yang, S.M.
Ye, Chem. J. Chin. Univ. 16 (1995) 1415.
[6] Y.F. Yuan, S.M. Ye, L.Y. Zhang, J.T. Wang, H.G. Wang,
Transition Met. Chem. 22 (1997) 561 and references therein.
[7] Y.F. Yuan, L.Y. Zhang, J.P. Cheng, J.T. Wang, Transition Met.
Chem. 22 (1997) 281.
[22] W. Bensch, M. Schuster, Z. Anorg. Allg. Chem. 615 (1992) 93.
[23] W. Bensch, M. Schuster, Z. Anorg. Allg. Chem. 611 (1992) 99.
[24] G. Kemp, A. Roodt, W. Purcell, K.R. Koch, J. Chem. Soc.,
Dalton Trans. (1997) 4481 and references therein.
[25] G.M.A. El-Reash, F.I. Taha, G. Badr, Transition Met. Chem.
15 (1990) 116.
[8] Y.F. Yuan, J.T. Wang, unpublished work.
[9] O. Seidelman, L. Bayer, R. Richter, Z. Naturforsch., Teil. B 50
(1995) 1679.
[10] D.J. Che, G. Li, X.L. Yao, Q.J. Wu, W.L. Wang, Y. Zhu, J.
Organomet. Chem. 584 (1999) 190 and references therein.
[11] D.J. Che, X.L. Yao, G. Li, Y.H. Li, J. Chem. Soc., Dalton
Trans. (1998) 1853 and references therein.
[12] J. Cernak, J. Chomic, P. Kutschy, D. Svrcinova, M. Dzurilla,
Inorg. Chim. Acta. 181 (1991) 85 and references therein.
[13] V.R. Richter, L. Beyer, J. Kaiser, Z. Anorg. Allg. Chem. 461
(1980) 67.
[14] G. Fitzl, L. Beyer, J. Sieler, R. Richter, J. Kaiser, E. Hoyer, Z.
Anorg. Allg. Chem. 433 (1977) 237.
[26] K.R. Koch, C. Sacht, T. Grimmbacher, S. Bourne, S. Afr. J.
Chem. 48 (1995) 71 and references therein.
[27] C. Sacht, M.S. Datt, Polyhedron 19 (2000) 1347 and references
therein.
[28] J.T. Wang, Y.F. Yuan, Y.M. Xu, Y.W. Zhang, R.J. Wang, H.G.
Wang, Acta Chim. Sinica 54 (1996) 32.
[29] J.T. Wang, Y.F. Yuan, Y.M. Xu, Y.W. Zhang, R.J. Wang, H.G.
Wang, J. Organomet. Chem. 481 (1994) 211.
[30] J.T. Wang, Y.W. Zhang, Y.M. Xu, Y.F. Yuan, S.H. Gao,
Chem. J. Chin. Univ. 14 (1993) 801.
[31] T. Steiner, Acta Crystallogr., Sect. B 54 (1998) 456.
[32] G.M. Sheldrick, SHELXL-97, A program for Crystal Structure
Refinement, University of Go¨ttingen, Germany, 1997.