Bis(triphenylphosphine)4-fluorobenzaldehyde thiosemicarbazone copper(I): Forcing chelation through oxoanions

Article abstract of DOI:10.1016/j.poly.2007.04.026

This paper reports the synthesis and characterization of six compounds of copper(I), stabilized in its reduced state by two triphenylphosphines, in which 4-fluorobenzaldehyde thiosemicarbazone and N-methylthiosemicarbazone act as chelating through their sulfur and imino nitrogen. The three oxoanions that have been chosen, NO₃^-, SO₄^2- and CH₃COO^-, play an important role: their oxygens are bad competitors with the imino nitrogen of the thiosemicarbazone moiety and moreover they form strong charge assisted hydrogen bondings that stabilize the neutral form of the ligand. The overall packing is determined by intermolecular phenyl-phenyl van der Waals interactions.

Full text of DOI:10.1016/j.poly.2007.04.026

Polyhedron 26 (2007) 3774–3782
www.elsevier.com/locate/poly
Bis(triphenylphosphine)4-fluorobenzaldehyde
thiosemicarbazone copper(I): Forcing chelation through oxoanions
*
Marisa Belicchi-Ferrari, Franco Bisceglie, Chiara Cavalieri, Giorgio Pelosi ,
Pieralberto Tarasconi
Dipartimento di Chimica Generale ed Inorganica, Chimica Analitica, Chimica Fisica, Viale G.P. Usberti 17/A,
`
Universita degli Studi di Parma, 43100 Parma, Italy
Received 14 March 2007; accepted 6 April 2007
Available online 1 May 2007
Abstract
This paper reports the synthesis and characterization of six compounds of copper(I), stabilized in its reduced state by two triphenyl-
phosphines, in which 4-fluorobenzaldehyde thiosemicarbazone and N-methylthiosemicarbazone act as chelating through their sulfur and
imino nitrogen. The three oxoanions that have been chosen, NO3ꢀ, SO42ꢀ and CH3COOꢀ, play an important role: their oxygens are bad
competitors with the imino nitrogen of the thiosemicarbazone moiety and moreover they form strong charge assisted hydrogen bondings
that stabilize the neutral form of the ligand. The overall packing is determined by intermolecular phenyl–phenyl van der Waals
interactions.
Ó 2007 Elsevier Ltd. All rights reserved.
Keywords: Copper(I) complexes; Thiosemicarbazones; X-ray analysis; Chelate
1. Introduction
sible configurations are conventionally called E and Z with
reference to the relative positions of the sulfur and the ter-
minal hydrazinic nitrogen in the thiolic form (Scheme 1).
It is reported that in their neutral form thiosemicarbaz-
ones bind to a metal in their E configuration, generally via
an S donor atom (Scheme 2, Ia), and after deprotonation
of the hydrazinic NH hydrogen the Z form is preferred
and they bind to the metal in an N,S-chelating mode
(Scheme 2, Ib) [3,5,10,17a,17b,17c].
Here we report our studies carried out to verify if the
presence of oxoanions can affect the bonding trends of this
class of compounds. Despite of the wide literature report-
ing data relative to Cu(II) thiosemicarbazone metal com-
plexes, few are the reports on structural considerations of
complexes of thiosemicarbazones with Cu(I) [2–6,10,17].
The reason for the lack of copper(I) thiosemicarbazone
studies can be related to their insolubility in many organic
solvents. It has been verified that tertiary phosphines play a
positive role in solubilizing Cu(I) complexes of thioamides
[3] and we have therefore taken advantage from this piece
of information to plan our experiments. With their d10
Thiosemicarbazones are a class of very interesting com-
pounds in many respects ranging from bonding and struc-
tural features presented by their metal complexes to their
pharmacological properties [1–10]. Copper(I) complexes
with various ligands with N, S, P potentially donor atoms
are of interest because of their wide variation in structural
motifs and rich photo-physical and chemical properties.
Many of these complexes have been reported to be lumi-
nescent and their emission behaviour varies with structures
and steric/electronic effects of the ligands [11–15]. The cur-
rent interest on thiosemicarbazone chemistry arises also
from the fact that the number of donor sites of the ligand
can be modulated in order to have mono or bidentate
ligands to tetradentate or polidentate macrocyclic ligands
[16]. Thiosemicarbazones present a thione–thiol equilib-
rium that confers them a planar geometry and the two pos-
*
Corresponding author. Tel.: +39 0521905420; fax: +39 0521905557.
E-mail address: giorgio.pelosi@unipr.it (G. Pelosi).
0277-5387/$ - see front matter Ó 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2007.04.026

M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
3775
S
powder formed in the reaction flask was filtered to separate
the product from Ph3PO and washed first with EtOH and
then with diethyl ether. Cu(NO3)2 Æ 3H2O, CuSO4 Æ 5H2O,
Cu(CH3CCO)2 Æ H2O were procured from Carlo Erba
while PPh3 was purchased from Aldrich. C, H, N, S anal-
yses were obtained with a Carbo-Erba 1108 instrument. IR
spectra were recorded using KBr pellets on a Nicolet 5PC
SH
NH2
SH
R
N
R
N
R
N
or
N
NH2
N
NH2
N
E
H
Z
Scheme 1. Thione/thiol equilibrium and conventional nomenclature for
the two thiolic forms.
1
FTIR spectrophotometer in the 4000–400 cmꢀ1 range. H
NMR spectra were recorded on a Bruker AC300 spectrom-
eter at 300 MHz in DMSO with TMS as the internal
reference.
Z
E
R2
N
R1
R
R1
R
- H+
NH
S
N
R3
N
M
N
N
R3
R2
S
2.2. Preparation of the ligands and of their complexes
M
Ia
Ib
4-Fluorobenzaldehyde thiosemicarbazone was prepared
by condensation of 4-fluorobenzaldehyde with thiosemicar-
bazide or N1-methylthiosemicarbazide in a 1:1 molar ratio
in ethanol using the procedure reported in the literature
[18].
Scheme 2. R1, R2 and R3 can be either H or organic radicals.
F
S
NH
N
H
N
R
2.2.1. Synthesis of [Cu(PPh3)2(Hfbt)]NO3 (1)
To a stirred solution of [Cu(PPh3)2NO3] (1.650 g,
2.54 mmol) in methanol (30 mL) was added an equimolar
amount of the ligand (0.502 g, 2.54 mmol) dissolved in
methanol (30 mL). The contents were stirred for 2 h at
room temperature. The clear solution was allowed to evap-
orate at room temperature and a yellow colored crystalline
product was formed. The isolated powder was recrystal-
lized from EtOH 95% and crystals apt for X-ray diffraction
were obtained (yield: 1.400 g, 65%; m.p.: 184 °C). The com-
plex is soluble in DMSO, CHCl3 and CH2Cl2. Anal. Calc.
for C44H38CuFN4O3P2S: C, 62.37; H, 4.52; N, 6.61; S,
3.78. Found: C, 62.45; H, 4.17; N, 6.64; S, 3.81%. Main
IR peaks (KBr, cmꢀ1): mas(NH2) 3442 m; ms(NH2) 3118
Scheme 3. Chemical drawing of Hfbt ligand (R = H) and Me-Hfbt ligand
(R = CH3).
electronic configuration Cu(I) ions do not have an energet-
ically preferred geometry and their coordination is there-
fore mainly governed by steric repulsions. Aside from the
two donor species P and S the remaining space around
the copper ion is usually occupied by a fourth ligand, usu-
ally a halide. In our experiments we have decided to verify
if the absence of other soft species can influence the coor-
dination and in particular if in these conditions the imino
nitrogen becomes a suitable donor for coordination. In this
paper, the complexes of 4-fluorobenzaldehyde thiosemicar-
bazones (Hfbt and Me-Hfbt, Scheme 2) with Cu(I) nitrate,
sulphate and acetate in the presence of triphenylphosphine
(Ph3P) are reported. The choice of these oxoanions was
envisaged to stabilize the ligand in the Z conformation
thank to their capability to form concerted hydrogen bonds
while the N-methylated derivative was used for comparison
to verify if the terminal amino hydrogen, not involved in
the aforementioned hydrogen bonds, can influence the
crystal packing. All of these compounds have been charac-
m; m(N–H) 3284 w, m(C–Haromatic) 3054 w, m(C–Caromatic
1627 s, 1506 s and 1480 s; m(C@N) 1602 s; m(C–P) 1433
vs; m(NO3) 1384 vs and 1293 s; m(C–F) 1234 s; d(C–Haromatic
)
)
1156 m and 1093 m; m(C@S) 827 m; c(C–Haromatic) 745 vs
and 695 vs. 1H NMR data (d, ppm; DMSO-d6): 7.25
(t, b, 8H, overlapped ligand Hm and PPh3Hp); 7.37 (t,
12H, PPh3Hm); 7.87 (dd, 2H, ligand Ho); 7.99 (s, 1H,
CH@N); 8.29 and 8.39 (2 s, 1H each, NH2); 11.61 (s, 1H,
C(S)NH).
2.2.2. Synthesis of [Cu(PPh3)2(Hfbt)]2SO4 Æ CH3OH (2)
To a stirred solution of [Cu2(PPh3)4SO4] (0.662 g,
0.52 mmol) in methanol (20 mL) was added a twofold
molar amount of the ligand (0.205 g, 1.04 mmol) dissolved
in methanol (20 mL). The contents were stirred for 2 h at
room temperature. A yellow powder was formed and the
product was filtered (yield: 0.600 g, 68%; m.p.: 132 °C).
The complex is soluble in DMSO, CHCl3 and CH2Cl2.
Anal. Calc. for C89H80Cu2F2N6O5P4S3: C, 62.93; H, 4.75;
N, 4.95; S, 5.66. Found: C, 62.51; H, 4.49; N, 4.83; S,
5.50%. Main IR peaks (KBr, cmꢀ1): mas(NH2) 3377 s;
ms(NH2) 3143 m; m(N–H) 3289 m, m(C–Haromatic) 3052 m,
1
terized by elemental analysis, IR, H NMR spectroscopy
and compounds 1, 5 and 6 also by X-ray crystallography
Scheme 3.
2. Experimental
2.1. Materials and techniques
[Cu(PPh3)2NO3], [Cu2(PPh3)4SO4] and [Cu(PPh3)2(CH3-
COO)] were prepared by reduction of the corresponding
Cu(II) salt using a fourfold excess of PPh3 in CH3OH at
reflux temperature for 1, 2 and 3 h, respectively. The white
m(C–Caromatic) and overlapped m(C@N) 1602 vs, m(C–Caromatic
)

3776
M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
1507 vs and 1480 s; m(C–P) 1434 vs; m(C–F) 1234 s; d(C–
Haromatic) 1155 s and 1094 s; m(SO4) 1121 s; m(C@S) 833
m; c(C–Haromatic) 745 vs and 696 vs. H NMR data (d,
ppm; DMSO-d6): 7.24 (t, b, 8H, overlapped ligand Hm
and PPh3Hp); 7.36 (t, 12H, PPh3Hm); 7.45 (t, 12H,
PPh3Ho); 7.86 (bs, 2H, ligand Ho); 7.99 (s, 1H, CH@N);
8.29 and 8.39 (2s, 1H each, NH2); 11.58 (s, 1H, C(S)NH).
room temperature. The clear solution was allowed to evap-
orate at room temperature and a yellow colored crystalline
product was formed. The isolated powder was dissolved in
warm EtOH 95% and crystals apt for X-ray diffraction
were obtained (yield: 1.050 g, 62%; m.p.: 143 °C). The com-
plex is soluble in DMSO, CHCl3 and CH2Cl2. Anal. Calc.
for C90H80Cu2F2N6O4P4S3: C, 63.78; H, 4.76; N, 4.96; S,
5.68. Found: C, 63.55; H, 4.68; N, 4.91; S, 5.51%. Main
IR peaks (KBr, cmꢀ1): m(NH) 3446 w, 3378 w, 3226 w;
m(C–Haromatic) 3051 m; m(C–Haliphatic) 2934 m; m(C–
1
2.2.3. Synthesis of [Cu(PPh3)2(Hfbt)]CH3COO (3)
To a stirred solution of [Cu(PPh3)2(CH3COO)] (0.672 g,
1.04 mmol) in methanol (25 mL) was added an equimolar
amount of the ligand (0.205 g, 1.04 mmol) dissolved in
methanol (25 mL). The contents were stirred for 2 h at
room temperature. The clear solution was allowed to evap-
orate and a yellow product was afforded (yield: 0.650 g,
76%; dec.: 178 °C). The complex is soluble in DMSO,
CHCl3 and CH2Cl2. Anal. Calc. for C46H41CuFN3O2P2S:
C, 65.43; H, 4.89; N, 4.98; S, 3.80. Found: C, 65.84; H,
4.78; N, 5.01; S, 3.69%. Main IR peaks (KBr, cmꢀ1):
m(NH2) 3481 m, 3382 m, 3141 w; m(NH) 3293 m, 3238 w;
m(C–Haromatic) 3052 m; mas(COO) 1580 s; m(C–Caromatic) 1596
C
aromatic) 1602 s, 1508 vs and 1480 s; m(C@N) 1567 m;
m(C–P) 1435 vs; m(C–N) 1329 m; m(C–F) 1233 s; d(C–Haromatic
1156 m and 1093 m; m(SO4) 1118 s; m(C@S) 831 m; c(C–
aromatic) 746 vs and 697 vs. 1H NMR data (d, ppm;
)
H
DMSO-d6): 2.08 (s, 3H, NCH3); 7.25 (t, b, 8H, overlapped
ligand Hm and PPh3 Hp); 7.37 (t, 12H, PPh3Hm); 7.44 (t,
12H PPh3Ho); 7.86 (dd, 2H, ligand Ho); 8.00 (s, 1H,
CH@N); 8.27 (s, 1H, NHCH3); 11.54 (s, 1H, C(S)NH).
2.2.6. Synthesis of {[Cu(PPh3)2(Me-Hfbt)]
CH3COO}2 Æ 2EtOH Æ H2O (6)
s and 1478 s; m(C–P) 1434 vs; m(C–F) 1229 s; d(C–Haromatic
)
To a stirred solution of [Cu(PPh3)2(CH3COO)] (0.619 g,
0.96 mmol) in ethanol 95% (25 mL) was added an equimolar
amount of the ligand (0.202 g, 0.96 mmol) dissolved in eth-
anol (15 mL). The contents were stirred for 2 h at reflux tem-
perature. The clear solution was allowed to evaporate at
room temperature and yellow-brown crystals suitable for
X-ray diffraction were afforded (yield: 1.280 g, 74%; m.p.:
144 °C). The complex is soluble in DMSO, CHCl3 and
CH2Cl2. Anal. Calc. for C98H100Cu2F2N6O7P4S2: C, 64.42;
H, 5.52; N, 4.60; S, 3.51. Found: C, 64.45; H, 5.55; N,
4.62; S, 3.53%. Main IR peaks (KBr, cmꢀ1): m(NH) 3378
w, 3238 w; m(C–Haromatic) 3053 m; m(C–Haliphatic) 2970 m;
mas(COO) 1619 vs; ms(COO) 1396 s; m(C–Caromatic) 1599 vs,
1507 vs and 1480 vs; m(C–P) 1434 vs; m(C–F) 1232 s; d(C–
1156 m and 1094 m; m(C@S) 834 m; c(C–Haromatic) 746 vs
1
and 696 vs. H NMR data (d, ppm; DMSO-d6): 2.10 (bs,
3H, CH3COO); 7.26 (t, b, 8H, overlapped ligand Hm and
PPh3Hp); 7.40 (t, 12H, PPh3Hm); 7.52 (t, 12H PPh3Ho);
7.95 (dd, 2 H, ligand Ho); 8.06 (s, 1H, CH@N); 8.30 and
8.41 (2s, 1H each, NH2); 11.54 (s, 1H, C(S)NH).
2.2.4. Synthesis of [Cu(PPh3)2(Me-Hfbt)]NO3 Æ CH3OH
(4)
To a stirred solution of [Cu(PPh3)2NO3] (1.134 g,
1.75 mmol) in methanol (25 mL) was added an equimolar
amount of the ligand (0.368 g, 1.74 mmol) dissolved in
methanol (20 mL). The contents were stirred for 2 h at
room temperature. The clear solution was allowed to evap-
orate at room temperature and a yellow colored powder
was obtained (yield: 1.078 g, 69%; m.p.: 100 °C). The com-
plex is soluble in DMSO, CHCl3 and CH2Cl2. Anal. Calc.
for C46H44CuFN4O4P2S: C, 61.84; H, 4.96; N, 6.27; S,
3.59. Found: C, 61.72; H, 4.65; N, 6.31; S, 3.53%. Main
H
aromatic) 1156 m and 1093 m; m(C@S) 832 m; c(C–Haromatic)
746 vs and 697 vs. 1H NMR data (d, ppm; DMSO-d6): 1.18
(t, 3H, CH3CH2OH), 2.10 (bs, 6H, NCH3 + CH3COO);
3.72 (q, 2H, CH3CH2OH), 7.28 (t, b, 8H, overlapped ligand
Hm and PPh3 Hp); 7.39 (t, 12H, PPh3Hm); 7.48 (t, 12H
PPh3Ho); 7.91 (dd, 2H, ligand Ho); 8.04 (s, 1H, CH@N);
8.34 (s, 1H, NHCH3); 11.58 (s, 1H, C(S)NH).
IR peaks (KBr, cmꢀ1): m(N–H) 3382 m, 3239 m, m(C–Haromatic
)
3052 w; m(C–Haliphatic) 2998 m; m(C–Caromatic) 1601 s, 1507 s
and 1480 s; m(C@N) 1566 s; m(C–P) 1434 vs; m(NO3) 1384 vs
and 1292 s; m(C–F) 1234 s; d(C–Haromatic) 1156 m and 1093
2.3. Crystallography
1
m; m(C@S) 834 w; c(C–Haromatic) 746 vs and 696 vs. H
Relevant data concerning data collection and details of
structure refinement are summarized in Table 1. Intensity
data were collected on a Philips PW1100 (compounds 1
and 6) and on a SMART 1000 Bruker AXS diffractometer
(compound 5) with Mo Ka radiation. Data from crystals of
compounds 1 and 6 collected on the Philips diffractometer
were non corrected for absorption while for compound 5
an absorption correction was carried out using the SADABS
[19] procedure. The WINGX [20] package was used all
through the refinement and completion of the structure.
The structures were solved using direct methods (SIR-97
[21]). Refinements were carried out by full matrix least-
NMR data (d, ppm; DMSO-d6): 2.99 (d, 3H, NCH3);
7.24 (t, b, 8H, overlapped ligand Hm and PPh3 Hp); 7.37
(t, 12H, PPh3Hm); 7.47 (t, 12H PPh3Ho); 7.86 (dd, 2H,
ligand Ho); 7.99 (s, 1H, CH@N); 8.56 (s, 1H, NHCH3);
11.44 (s, 1H, C(S)NH).
2.2.5. Synthesis of [Cu(PPh3)2(Me-Hfbt)]2SO4 (5)
To a stirred solution of [Cu2(PPh3)4SO4], (0.631 g,
0.50 mmol) in methanol (35 mL) was added a twofold
molar amount of the ligand (0.209 g, 1.00 mmol) dissolved
in methanol (15 mL). The contents were stirred for 2 h at

M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
3777
Table 1
Experimental data for crystallographic analyses
Compound
1
2
3
Chemical formula
Formula weight
Space group (no.)
C44H38CuFN4O3P2S
847.32
C90H80Cu2F2N6O4P4S3
1694.74
P21/c(14)
18.117(3)
18.336(3)
25.211(4)
90.0
91.830(3)
90.0
8371(2)
4
C98H100Cu2F2N6O7P4S2
1827.01
ꢀ
ꢀ
P1ð2Þ
P1ð2Þ
˚
a (A)
13.490(3)
14.064(3)
11.318(3)
94.36(2)
106.47(3)
96.37(2)
2033.4(9)
2
14.168(1)
17.550(1)
20.231(1)
108.638(1)
94.385(1)
90.019(1)
4751.0(5)
2
˚
b (A)
˚
c (A)
a (°)
b (°)
c (°)
3
˚
V (A )
Z
F(000)
T (K)
876
298.15
1.384
7.17
0.71069
0.056
3512
298.15
1.345
7.18
0.71069
0.0548
0.1184
1908
298.15
1.277
6.19
0.71069
0.0486
0.0992
Dcalc (Mg/m3)
l (cmꢀ1
)
˚
k (A)
R
Rw2
0.1021
P
P
R = iFoi ꢀ Fci/ jFoj.
P
Rw2 = {P[w(Fo ꢀ Fc2)2]/ [w(Fo2)2]}
.
2
1/2
squares cycles SHELXL97 [22] for all compounds. The hydro-
gen atoms were calculated with standard geometry and
refined in riding position. Atomic scattering factors were
taken from the International Tables for Crystallography
[23]. The program PARST [24] was employed for the geomet-
rical description and ORTEP [25] and MERCURY [26] for the
drawings.
For this reason it is not always observed in the IR spectra
of complexes a shift to lower frequencies with respect to the
free ligand. The absorption at ca. 1394 and 1293 cmꢀ1 are
assigned to the absorptions of the non coordinated inor-
ganic ligand. NMR data suggest that also in solution
ligands are in their neutral form as can be observed from
the presence at 11.61 ppm for (1) and 11.44 ppm for (4).
With respect of NMR data of the free ligands, a slight shift
to low field of N–H protons is observed (up to 0.20 ppm).
Similar considerations can be also drawn for complexes
3. Results and discussion
2ꢀ
3.1. Synthesis and spectroscopy
(2) and (5) obtained from SO4 and (3) and (6) from
CH3COOꢀ anions. In particular for (2) and (5) can be
observed the presence at 1120 cmꢀ1 strong absorption of
ionic SO42ꢀ. The IR spectra of complexes (3) and (6) result
more complicated because of the presence of CH3COOꢀ
asymmetric and symmetric stretchings.
Compounds (1), (5) and (6) afforded crystals suitable for
X-ray diffraction studies and structural data allow for a
correlation between structures andꢀspectroscopic data. As
for complexes obtained from NO3 is concerned, the IR
spectral behaviour of (1) and (4) is very similar in all the
observed range. This allows to suppose that the Me-Hfbt
ligand of complex (4) is in the same environment of com-
plex (1). It is useful to note that the same differences found
between complex (1) and its free ligand are also found
between (4) and its free ligand. The IR absorptions of the
C@S groups are shifted at lower frequencies with respect
to the free ligand (827 cmꢀ1 for (1) versus 836 cmꢀ1 and
834 cmꢀ1 for (4) versus 837) indicating the weakening of
the C@S bond after coordination. Changes in the spectral
ranges between 1500 and 1600 cmꢀ1 (mC@N) and between
1130 and 1340 cmꢀ1 (NC(@S)N absorptions) indicate the
C@N involvement in coordination. It can also be generally
observed a broadening of the m(NH) absorptions, showing
a different behaviour of the hydrogen bonding network in
the complexes with respect to the free ligands. This can
be due to the fact that also in the free ligands at the solid
state N–H bonds are involved in strong hydrogen bonds.
In this way for all complexes a tetrahedral coordination
by means of S,N, P, P can be assumed.
3.2. Crystal structures of the complexes
The syntheses allowed to isolate in crystalline form com-
plexes (1), (5) and (6) and in order to establish their struc-
tural features, single crystal X-ray crystallography
experiments were carried out (Table 2).
In Fig. 1 is reported the ORTEP view of complex
Cu(PPh3)2(Hfbt)]NO3 (1). The structure can be described
as formed by a cationic complex molecule with a nitrate
as a counterion and the copper(I) ion coordinates two
triphenylphosphines and a parafluorobenzaldehyde thio-
semicarbazone molecule in its neutral form. The thiosemi-
carbazone binds to the metal through the sulfur and the
iminic nitrogen and forms a five-term chelation ring with
an angle N–Cu–S of 85.13(5)°. The P–Cu–P angle is rather

3778
M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
Table 2
˚
Selected bond distances (A) and angles (°) for compounds 1, 5 and 6
1
5
6
Cu(1)–P(1)
Cu(1)–P(2)
Cu(1)–S(1)
Cu(1)–N(3)
N(2)–N(3)
C(1)–N(1)
C(1)–N(2)
C(1)–S(1)
C(2)–N(3)
C(2)–C(3)
C(3)–C(8)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(6)–F(1)
C(6)–C(7)
C(7)–C(8)
C(9)–N(1)
2.3056(7)
2.2521(7)
2.3482(8)
2.136(2)
1.380(2)
1.327(3)
1.337(3)
1.693(2)
1.286(2)
1.454(3)
1.381(3)
1.380(3)
1.374(3)
1.356(3)
1.352(3)
1.357(4)
1.375(4)
2.273(2)
2.295(2)
2.354(2)
2.164(6)
1.387(8)
1.338(9)
1.341(9)
1.685(8)
1.290(9)
1.457(11)
1.374(11)
1.352(11)
1.374(12)
1.318(13)
1.382(10)
1.336(13)
1.385(12)
1.440(10)
2.261(2)
2.286(2)
2.337(3)
2.117(8)
1.350(9)
1.331(10)
1.331(12)
1.709(9)
1.323(10)
1.425(12)
1.363(13)
1.425(13)
1.419(14)
1.355(15)
1.370(13)
1.324(17)
1.380(16)
1.444(11)
2.294(1)
2.293(1)
2.337(1)
2.162(4)
1.386(5)
1.330(6)
1.349(6)
1.688(5)
1.282(5)
1.462(6)
1.385(6)
1.388(6)
1.376(7)
1.362(7)
1.362(6)
1.363(7)
1.380(6)
1.441(6)
2.284(1)
2.260(1)
2.338(1)
2.171(4)
1.376(5)
1.329(5)
1.345(5)
1.689(4)
1.293(5)
1.453(7)
1.372(7)
1.395(7)
1.374(9)
1.345(10)
1.359(7)
1.363(9)
1.374(7)
1.444(6)
N(3)–Cu(1)–P(2)
N(3)–Cu(1)–P(1)
P(2)–Cu(1)–P(1)
N(3)–Cu(1)–S(1)
P(2)–Cu(1)–S(1)
P(1)–Cu(1)–S(1)
C(1)–N(1)–C(9)
C(1)–N(2)–N(3)
C(2)–N(3)–N(2)
C(2)–N(3)–Cu(1)
N(2)–N(3)–Cu(1)
N(1)–C(1)–N(2)
N(1)–C(1)–S(1)
N(2)–C(1)–S(1)
N(3)–C(2)–C(3)
C(8)–C(3)–C(4)
C(8)–C(3)–C(2)
C(4)–C(3)–C(2)
C(5)–C(4)–C(3)
C(6)–C(5)–C(4)
F(1)–C(6)–C(5)
F(1)–C(6)–C(7)
C(5)–C(6)–C(7)
C(6)–C(7)–C(8)
C(7)–C(8)–C(3)
125.07(5)
99.64(5)
126.83(3)
85.13(5)
110.68(3)
99.21(3)
102.6(2)
114.9(2)
135.39(8)
83.9(2)
114.8(2)
108.1(2)
128.52(9)
85.8(2)
113.9(1)
116.3(1)
121.20(5)
84.8(1)
122.8(1)
104.1(1)
123.15(5)
83.8(1)
104.65(8)
102.69(8)
122.3(7)
121.1(6)
113.7(6)
132.8(5)
112.9(5)
113.1(7)
123.1(7)
123.7(6)
122.4(8)
117.5(8)
119.9(8)
122.6(8)
122.3(9)
118.1(10)
119.0(11)
117.7(10)
123.2(9)
118.5(9)
120.3(9)
107.46(9)
102.65(9)
123.5(9)
123.1(8)
113.0(8)
134.3(6)
112.6(6)
116.0(9)
120.8(8)
123.2(7)
124.5(9)
116.9(10)
116.2(11)
126.6(10)
121.8(10)
116.8(12)
115.7(13)
119.6(13)
124.6(13)
118.7(13)
121.0(12)
108.15(5)
104.93(5)
124.7(5)
122.7(4)
113.8(4)
134.4(3)
111.8(3)
114.4(4)
122.4(4)
123.1(4)
126.1(4)
118.0(5)
123.9(4)
118.1(4)
121.1(5)
118.8(5)
119.4(5)
118.2(5)
122.4(5)
118.4(5)
121.4(5)
106.55(5)
108.88(5)
124.3(4)
123.0(4)
114.1(4)
131.4(3)
111.4(3)
115.0(4)
122.7(4)
122.3(4)
124.8(5)
118.4(5)
123.8(5)
117.8(5)
119.9(6)
119.5(6)
119.1(7)
118.3(8)
122.6(6)
118.0(6)
121.6(5)
122.8(2)
112.9(2)
133.5(1)
111.6(1)
115.1(2)
121.1(2)
123.7(2)
125.4(2)
117.7(2)
117.7(2)
124.6(2)
121.8(2)
118.3(2)
119.1(2)
118.6(2)
122.2(2)
118.9(3)
121.0(3)
wide (125.07(5)°) and the copper tetrahedral coordination
The main feature that characterizes the packing of these
molecules is a so-called sixfold phenyl embrace (6PE)
[27a,27b,27c,27d] (P1. . .P1I I = (1 ꢀ x, ꢀy, ꢀz) distance
is therefore strongly distorted. The coordination bonds
˚
have distances that range from 2.136(2) A for the Cu1–
˚
˚
N3 bond to 2.3482(8) A for the Cu1–S1 bond. The nitrate
6.979 A) (see Fig. 2) between two centrosymmetrically
ion forms a strong charge assisted H-bonding with the thi-
osemicarbazone NH groups through two of its oxygens
(see Table 3). The thiosemicarbazone moiety, that should
be expected to be planar because of the extended conju-
gated system of double bonds, is significantly distorted:
the angle between the average plane of the 4-fluorobenzal-
dehyde ring and that of the thiosemicarbazide moiety is
23.63(7)°. This distortion can be interpreted as a double
interaction of the fluorophenyl moiety with two phenyls
belonging to two different triphenylphosphines.
related molecules. The phenyls of the triphenylphosphines
involved in this interaction present what the aforemen-
tioned paper calls a ‘‘good rotor’’ conformation with tor-
sion angles (defined by the copper, the phosphorus, the
ipso carbon and the next carbon atom of the phenyl group
which gives the torsion angle in the range 90°, ꢀ90°) of
43.53°, 45.69° and 49.21° while the other triphenylphos-
phine has a more irregular conformation (torsion angles
of 23.90°, 37.31°, 78.23°) due to an edge-to-face interaction
between the fluorobenzene group with a tpp phenyl group.

M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
3779
F1
C2
O2
O3
P2
N4
N2
Cu1
N3
O1
N1
S1
P1
Fig. 2. MERCURY drawing of the packing of compound (1) showing the two
molecules (capped sticks) involved in the six phenyl embrace and the
looser pheny–phenyl interactions between adjacent molecules (in
wireframe).
Fig. 1. ORTEP drawing of complex Cu(PPh3)2(Hfbt)]NO3 (1) showing
thermal ellipsoids at the 50% probability level.
charge assisted H-bonds connecting the two complex mol-
ecules A and B (see Table 3).
Also this packing is determined by a very tight six-atom
phenyl embrace characterized by a P4. . .P4I (I = ꢀ x,
˚
Table 3
1 ꢀ x, ꢀz) interaction with a distance of 6.645 A (see
˚
Relevant hydrogen bonds (A, °) found in molecule 1, 5 and 6
Fig. 4), much shorter than that observed in the previous
one. A looser sixfold phenyl embrace is observed between
Compound 1 N1. . .O1(nitrate)
N2. . .O2(nitrate)
2.906(3)
2.717(2)
N1–H. . .O1
N2–H. . .O2
178(3)
166(3)
I
˚
P2 and P3 (I = ꢀ x, ꢀ1/2 + y, 1/2 ꢀ z) (distance 7.66 A)
Compound 5 N1. . .O4(sulfate)
N2. . .O3(sulfate)
2.751(9)
2.740(9)
2.757(10) N4–H. . .O2
2.902(10) N5–H. . .O1
N1–H. . .O4
N2–H. . .O3
135.5(5)
156.4(5)
153.4(5)
170.2(5)
and this interaction together with the previously described
contact form a bidimensional layer of molecules that lie on
the yz plane. These layers are connected by a third interac-
tion between two tpp that is characterized by a longer
N4. . .O2(sulfate)
N5. . .O1(sulfate)
I
Compound 6 N1. . .O2(acetate 1) 2.701(7)
N2. . .O1(acetate 1) 2.746(6)
N1–H. . .O2
N2–H. . .O1
N4–H. . .O4
N5–H. . .O3
O5–H. . .O1
168.6(3)
160.1(3)
165.4(3)
168.6(3)
145.4(4)
˚
P. . .P distance of 7.785 A [P1. . .P3 I = 1 + x, y, z].
The crystal structure of compound 6 {[Cu(PPh3)2(Me-
Hfbt)]CH3COO}2 Æ 2EtOH Æ H2O is reported in Fig. 5. In
the asymmetric unit are present two independent complex
cations, two acetate ions, two ethanol molecules and a
water. The carboxyl group of the acetate forms two hydro-
gen bonds (see Table 3) with the NH groups of the thio-
N4. . .O4(acetate 2) 2.805(6)
N5. . .O3(acetate 2) 2.720(6)
O5(ethanol). . .O1
(acetate)
O6(ethanol). . .O4
(acetate)
2.645(6)
2.792(9)
O6–H. . .O4
154.6(6)
semicarbazide moiety in
a way analogous to that
observed in the nitrate derivative previously discussed (1).
Moreover one of the two carboxylic oxygens (different in
molecule A and in molecule B, see Fig. 6) in both acetates
is also involved in a bifurcated but strong hydrogen bond
with the ethanols (see Table 3). As in the previous case in
the two complex molecules the thiosemicarbazone ligands
have different planarities and precisely a dihedral angle
between the thiourea moiety and the aromatic ring of
8.5(2)° in molecule A and 37.0(2)° in molecule B. Notewor-
thy the P–Cu–P angles [121.20(5)° and 123.15(5)°] that are
by far smaller than those found in the other two complexes
[126.83(3)° in compound 1 and 135.39(8)° and 128.52(9)° in
compound 5].
To complete the description of the packing it is noteworthy
to observe the presence of two longer P. . .P distances due
to the presence of two pairs of phenyls belonging to two
centrosymmetrically related molecules that interact edge-
to-face (see Fig. 2). The other N terminal hydrogen atom
seem to play no role in the packing.
The structure of compound 5, [Cu(PPh3)2(Me-
Hfbt)]2SO4, is reported in Fig. 3. The asymmetric unit is
formed by two complex [Cu(PPh3)2(Me-Hfbt)]+ cations
bridged by a sulfate anion. The two cationic moieties differ
significantly in their geometrical features. One of the thio-
semicarbazone ligand (molecule A) presents a marked dihe-
dral angle (43.6(3)°) between the average plane of the
thiosemicarbazide moiety and that of the fluorobenzyl ring,
while in the other (molecule B) is almost planar (the same
dihedral angle is 2.91(3)°). The sulfate ion forms two
A series of considerations must be done on the hydrogen
bonding system found in these compounds. A common fea-
ture is the strong charge assisted hydrogen bondings that
stabilize the ligand in its neutral form. In particular some

3780
M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
S2
Cu1
S1
N1
O4
Cu2
N2
N4
O2
N5
A
S3
O1
O3
B
Fig. 3. ORTEP drawing of complex [Cu(PPh3)2(Me-Hfbt)]2SO4 (5) showing thermal ellipsoids at the 50% probability level.
of these hydrogen bonds formed with the acidic hydrazinic
nitrogen are among the shortest observed in the literature.
Using a thiourea moiety as a reference we have found in
the CSD [28a,28b] that the average N–H. . .O distance is
˚
˚
2.918(8) A for the nitrate ion, 2.872(12) A for the sulfate
˚
ion and 2.882(9) A for the acetate that are comparable with
the distances observed for the aminic NH in compound 1
˚
(2.906(3) A) while those found in complex 5 (2.751(33)
˚
and 2.757(10) A) and in compound 6 (2.701(7) and
˚
2.805(6) A) are remarkably shorter. The hydrogen bonds
that involve the hydrazinic nitrogen are very strong with
˚
˚
distances of 2.717(2) A for 1, 2.740(9) A in 5 and
˚
˚
2.746(6) A and 2.720(6) A in 6. The only exception is the
hydrazinic N of molecule B of compound 5 (2.902(9) A)
˚
Fig. 4. MERCURY drawing of the packing of compound (5) showing two
sulphate bridged dimeric molecules involved in the P4. . .P4 six phenyl
embrace.
in which the distance is larger than the average and this dis-
tortion is probably due to the packing.
B
O3
O4
P1
N5
N4
Cu1
P2
P3
Cu2
S1
S2
N3
P4
N1
N2
O1
O2
A
Fig. 5. ORTEP drawing of the moiety {[Cu(PPh3)2(Me-Hfbt)]CH3COO}2 of complex (6) showing thermal ellipsoids at the 50% probability level.

M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
3781
Fig. 6. MERCURY drawings of the hydrogen bond patterns around the acetate ion in the two independent molecules in compound 6.
[6] A.R. Cowley, J.R. Dilworth, P.S. Donnelly, E. Labisbal, A. Sousa, J.
Am. Chem. Soc. 124 (2002) 5270.
4. Conclusions
[7] D.B. Lovejoy, D.R. Richardson, Blood 100 (2002) 666.
[8] L.-J. Ming, Med. Res. Rev. 23 (2003) 697.
[9] M. Belicchi-Ferrari, G. Gasparri-Fava, C. Pelizzi, P. Tarasconi,
Inorg. Chim. Acta 97 (1985) 99.
[10] M. Belicchi-Ferrari, G. Gasparri-Fava, M. Lanfranchi, C. Pelizzi, P.
Tarasconi, Inorg. Chim. Acta 181 (1991) 253.
[11] X.-H. Zhou, T. Wu, D. Li, Inorg. Chim. Acta 359 (2006) 1442.
[12] V.W.W. Yam, W.K. Lee, K.K. Cheun, J. Chem. Soc., Dalton Trans.
(1996) 2335.
[13] V.W.W. Yam, K.K.W. Lo, Chem. Soc. Rev. 28 (1999) 323.
[14] D. Li, W.J. Shi, L. Hou, Inorg. Chem. 44 (2005) 3907.
[15] J.A. Simon, W.E. Palke, P.C. Ford, Inorg. Chem. 35 (1996) 6413.
[16] (a) P. Souza, A.I. Matesanz, C. Pastor, Inorg. Chem. Commun. 5
(2002) 344;
As hypothesized in the introduction the main features
presented by these copper(I) complex molecules are deter-
mined by three factors: (a) the absence of soft donor atoms,
besides P and S, that force the imino nitrogen to coordinate
to the metal center; (b) the overall flatness of the thiosemi-
cabazone moiety that allows its insertion in the cleft
formed by the bulky blob of the two triphenylphosphines
and, (c) the presence of the charged assisted hydrogen
bonds formed by the anions that contribute to the Z con-
figuration of the ligand. A contribution that is not predict-
able in the detail but that is decisive in understanding the
overall packing and some distortions in the planarity of
the thiosemicarbazone ligand in the crystal is the extended
system of weak interactions among the aromatic rings.
´
(b) R. Pedrido, M.R. Bermejo, M.J. Romero, A.M. Gonzalez-Noya,
´
M. Maneiro, M.I. Fernandez, Inorg. Chem. Commun. 8 (2005) 1036.
[17] (a) J.S. Casas, M.S. Garcia-Tasende, J. Sordo, Coord. Chem. Rev.
209 (2000) 197;
(b) M.J.M. Campbell, Coord. Chem. Rev. 15 (1975) 279;
(c) S.B. Padhye, G. Kauffman, Coord. Chem. Rev. 63 (1985) 127;
(d) D.X. West, A.E. Liberta, S.B. Padhye, R.C. Chikate, P.B.
Sonawane, A.S. Kumbhar, R.G. Yerande, Coord. Chem. Rev. 123
(1993) 49;
(e) R.L. De Lima, L.R.D. Teixeira, T.M.G. Carneiro, H. Beraldo, J.
Braz. Chem. Soc. 10 (1999) 184;
(f) N.T. Akinchan, R. Akinchan, P.M. Drozdewski, Y.H. Yang, T.L.
Klein, D.X. West, Synth. React. Inorg. Met.-Org. Chem. 26 (1996)
1735;
Appendix A. Supplementary material
CCDC 640078, 640079 and 640080 contain the supple-
mentary crystallographic data for 1, 5 and 6. These data
can be obtained free of charge via http://www.ccdc.cam.ac.
uk/conts/retrieving.html, or from the Cambridge Crystal-
lographic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@
ccdc.cam.ac.uk. Supplementary data associated with this
article can be found, in the online version, at
doi:10.1016/j.poly.2007.04.026.
(g) H.G. Zheng, D.X. Zeng, X.Q. Xin, W.T. Wong, Polyhedron 16
(1997) 3499;
(h) S. Lhuachan, S. Siripaisarnpipat, N. Chaichit, Eur. J. Inorg.
Chem. (2003) 263;
(i) L.J. Ashfield, A.R. Cowley, J.R. Dilworth, P.S. Donnelly, Inorg.
Chem. 43 (2004) 4121;
(j) M. Belicchi-Ferrari, A. Bonardi, G. Gasparri-Fava, C. Pelizzi, P.
Tarasconi, Inorg. Chim. Acta 223 (1994) 77;
References
[1] T.S. Lobana, Rekha, A.P.S. Pannu, G. Hundal, R.J. Butcher, A.
Castineiras, Polyhedron (2007), doi:10.1016/j.poly.2006.12.044.
[2] T.S. Lobana, Rekha, R.J. Butcher, Trans. Met. Chem. 29 (2004) 291.
[3] T.S. Lobana, Rekha, R.J. Butcher, A. Castineiras, E. Bermejo, P.V.
Bharatam, Inorg. Chem. 45 (2006) 1535.
[4] D.X. West, S.B. Padhye, P.B. Sonawane, Struct. Bond. (Berlin) 76
(1991) 4.
[5] D.R. Smith, Coord. Chem. Rev. 164 (1997) 575.
(k) T.S. Lobana, Rekha, B.S. Sidhu, A. Castineiras, E. Bermejo, T.
Nishioka, J. Coord. Chem. 58 (2005) 803;
(l) T.S. Lobana, S. Khanna, R.J. Butcher, A.D. Hunter, M. Zeller,
Polyhedron 25 (2006) 2755.
[18] M. Belicchi-Ferrari, S. Capacchi, G. Reffo, G. Pelosi, P. Tarasconi, R.
Albertini, S. Pinelli, P. Lunghi, J. Inorg. Biochem. 81 (2000) 89.
[19] G.M. Sheldrick, SADABS. Program for Empirical Absorption correc-
tion of Area Detector Data, University of Gottingen, Germany, 1996.

3782
M. Belicchi-Ferrari et al. / Polyhedron 26 (2007) 3774–3782
[20] L.J. Farrugia, J. Appl. Cryst. 32 (1999) 837–838.
[21] A. Altomare, M.C. Burla, M. Camalli, G. Cascarano, C. Giacovazzo,
A. Guagliardi, A.G.G. Moliterni, G. Polidori, R. Spagna, SIR 97, J.
Appl. Cryst. 32 (1999) 115.
[26] C.F. Macrae, P.R. Edgington, P. McCabe, E. Pidcock, G.P. Shields,
R. Taylor, M. Towler, J. van de Streek, J. Appl. Cryst. 39 (3) (2006)
453.
[27] (a) I.G. Dance, M.L. Scudder, J. Chem. Soc., Chem. Commun. (1995)
[22] G. Sheldrick, SHELXL 97 A Program for Structure Refinement,
University of Gottingen, Germany, 1997.
1039;
(b) Chem. Eur. J. 2 (1996) 481;
[23] International Tables for X-ray Crystallography, vol. 4, Kynoch Press,
Birmingham, UK, 1974.
(c) I. Dance, M. Scudder, J. Chem. Soc., Dalton Trans. 10 (2000)
1579;
[24] M. Nardelli, PARST95. An update to PARST: a system of Fortran
routines for calculating molecular structure parameters from the
results of crystal structure analyses, J. Appl. Cryst. 28 (1995)
659.
[25] C.K. Johnson, M.N. Burnett, ORTEPIII. Report ORNL-6895, Oak
Ridge National Laboratory, TN, USA, 1996.
(d) I. Dance, M. Scudder, J. Chem. Soc., Dalton Trans. 10 (2000)
1587.
[28] (a) F.H. Allen, Acta Crystallogr., Sect. B 58 (2002) 380;
(b) I.J. Bruno, J.C. Cole, P.R. Edgington, M. Kessler, C.F. Macrae,
P. McCabe, J. Pearson, R. Taylor, Acta Crystallogr., Sect. B 58
(2002) 389.