Copper(II) complexes of aliphatic tridentate amine/dithioether ligands - Synthesis and molecular structures

Article abstract of DOI:10.1016/j.ica.2012.04.023

Three new tridentate ligands (1-3) featuring a central secondary amine linked by ethylene bridges to two thioether donor functions with S-methyl or S-benzyl substituents have been synthesized and reacted with copper(II) chloride or copper(II) nitrate. The resulting complexes of type [CuX₂(L)] (L = amine-dithioether ligand) 6, 7, and 9 exhibit a square-pyramidal coordination geometry with the nitrogen and sulfur donor groups of the tridentate ligand occupying three of the basal binding sites at the metal ion. Two chloro (6 and 7) or a nitrato ligand (9) originating from the metal precursor salt complete the coordination sphere of the copper(II) ion. The apical donors are bonded with significantly longer bond distances compared to identical donors in the basal plane. The weakly bound apical chloro ligand of 6 can be abstracted with silver(I) nitrate effecting the formation of the dinuclear complex 10 featuring a nitrato ligand coordinated to two copper(II) centers in a bridging fashion. For all copper(II) complexes the observed Cu-S bond distances are very similar and not significantly influenced by alteration of the alkyl group at the thioether donor function.

Full text of DOI:10.1016/j.ica.2012.04.023

Inorganica Chimica Acta 390 (2012) 143–147
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Note
Copper(II) complexes of aliphatic tridentate amine/dithioether ligands – Synthesis
and molecular structures
⇑
Marc Blomenkemper, Henning Schröder, Tania Pape, F. Ekkehardt Hahn
Institut für Anorganische und Analytische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 30, 48149 Münster, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Three new tridentate ligands (1–3) featuring a central secondary amine linked by ethylene bridges to two
thioether donor functions with S-methyl or S-benzyl substituents have been synthesized and reacted
with copper(II) chloride or copper(II) nitrate. The resulting complexes of type [CuX2(L)] (L = amine-dith-
ioether ligand) 6, 7, and 9 exhibit a square-pyramidal coordination geometry with the nitrogen and sulfur
donor groups of the tridentate ligand occupying three of the basal binding sites at the metal ion. Two
chloro (6 and 7) or a nitrato ligand (9) originating from the metal precursor salt complete the coordina-
tion sphere of the copper(II) ion. The apical donors are bonded with significantly longer bond distances
compared to identical donors in the basal plane. The weakly bound apical chloro ligand of 6 can be
abstracted with silver(I) nitrate effecting the formation of the dinuclear complex 10 featuring a nitrato
ligand coordinated to two copper(II) centers in a bridging fashion. For all copper(II) complexes the
observed Cu–S bond distances are very similar and not significantly influenced by alteration of the alkyl
group at the thioether donor function.
Received 13 February 2012
Accepted 16 April 2012
Available online 25 April 2012
Keywords:
Mixed donor ligands
Sulfur donor function
Tridentate ligands
Copper
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
triamines exhibit a variation of the geometric parameters depend-
ing on the lengths of the ligand arms [7]. Recently we reported on a
As essential part of many biological systems copper exhibits a
divers and fascinating coordination chemistry. In particular the in-
tensely blue colored CuII-sites of cupredoxins like azurin or plasto-
cyanin have interested chemists for many years due to their
exceptional spectroscopic and structural properties [1]. In the ac-
tive centers of these enzymes the copper(II) ion is coordinated by
two histidine nitrogen atoms and a cystein thiolato donor. The cop-
per coordination sphere is usually completed by one or two weakly
bound ligands resulting in a distorted tetrahedral or trigonal–bipy-
ramidal complex geometry [2]. In many cupredoxins these addi-
tional ligands are thioether donors, e.g. methionine residues. An
often observed problem during the synthesis of model compounds
for copper(II) enzymes is the facile oxidation of thiolato ligands to
the corresponding disulfides by the metal center [3]. One approach
to prevent this undesired reaction is the substitution of the thiolato
donor function by a more stable thioether group [4].
series of copper(I) complexes with tris(x-benzylmercaptoalkyl)
amine ligands [8]. The geometry at the metal center turned out
to be highly dependent on the ligand arm lengths and can be grad-
ually adjusted from trigonal–pyramidal (exclusively ethylene spac-
ers) to tetrahedral (exclusively propylene spacers). For related
complexes with tripodal ligands featuring thioether donor func-
tions a significant dependence of the structural and spectroscopic
properties on the alkyl or aryl substituents of the thioether was ob-
served [9,10]. Berreau et al. synthesized copper(II) complexes with
N-centered tripodal ligands with two pyridyl and one thioether do-
nor group [9]. While the complex with an ethyl thioether substitu-
ent exhibits the trigonal–bipyramidal geometry, the analogous
compound with an aromatic phenyl thioether is square-pyramidal.
The Cu–S bond distances differ significantly with values of
2.418(1) Å for the ethyl and 2.701(1) Å for the phenyl derivative.
Herein, we report on the coordination chemistry towards cop-
per(II) of three novel ligands with thioether donors. The syntheses
of the tridentate ligands featuring a secondary amine and two thi-
oether donor functions with different substituents as well as the
preparation and molecular structures of their copper(II) com-
plexes are presented and discussed. Some complexes of related li-
gands with two thiolato donor functions have been described
previously [11].
N-centered tripodal ligands are frequently used to model the
active sites of metallo proteins [5] and various symmetric and
asymmetric tripodal ligands containing different donor functions
[6] including a number of ligands of type N[(CH2)x–SH]3 have been
described [6e–i]. Complexes bearing N-centered tripodal aliphatic
⇑
Corresponding author. Fax: +49 251 8333108.
E-mail address: fehahn@uni-muenster.de (F.E. Hahn).
0020-1693/$ - see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.ica.2012.04.023

144
M. Blomenkemper et al. / Inorganica Chimica Acta 390 (2012) 143–147
2. Results and discussion
X
H
SR
N
CuX2
R
S
X
HN
The symmetric tridentate ligands 1 and 2 were synthesized by a
nucleophilic substitution of the halides of bis(2-chloroethyl)amine
hydrochloride with methylthiolate or benzylthiolate [12], respec-
tively (Scheme 1). For the preparation of the asymmetric ligand 3
bearing both methyl and benzyl thioether donor functions 2-(mer-
captomethyl)ethylamine 4 was prepared from 2-bromoethylamine
hydrobromide and subsequently N-alkylated with 2-(mercaptob-
enzyl)ethylbromide 5 [13]. Compounds 2 and 5 have been used
previously as precursors for tripodal ligands [8].
The mononuclear copper(II) complexes [CuCl2(1)] 6, [CuCl2(2)]
7, [CuCl2(3)] 8, and [Cu(NO3)2(3)] (9) were prepared by the reaction
of the appropriate ligands with copper(II) chloride or copper(II) ni-
trate dihydrate in acetonitrile (Scheme 2). Treatment of compound
6 with one equivalent of silver(I) nitrate in acetonitrile leads to the
abstraction of one of the chloro ligands and formation of the dinu-
Cu
SR´
MeCN
S
R´
6
7
8
9
: R = R´ = Me, X = Cl
: R = R´ = Bn, X = Cl
: R = Bn, R´ = Me, X = Cl
: R = Bn, R´ = Me, X = NO3
1
2
3
: R = R´ = Me
: R = R´ = Bn
: R = Bn, R´ = Me
H
H
NO3
Cl
N
N
AgNO3
−AgCl
S
S
N
S
Cu
Cl
Cu
Cu
S
O
O
S
S
Cl
N
O
10
Cl
6
clear complex [{CuCl(1)}2(l-NO3)]NO3 10 featuring a bridging nit-
rato ligand. Dark green single crystals of 6, 7, 9, and 10 which were
suitable for X-ray diffraction analyses have been obtained by slow
diffusion of diethyl ether into saturated solutions of the complexes
in acetonitrile.
Scheme 2. Synthesis of the copper(II) complexes 6–10.
The molecular structures of complexes 6, 7 and 9 (Figs. 1–3)
confirm the proposed composition of he complexes and the coordi-
nation of the copper(II) center by the amine and the two thioether
donor functions of the tridentate ligands. The remaining coordina-
tion sites at CuII are occupied by two counterions of the metal pre-
cursor salt, i.e. chloro (for 6 and 7) or nitrato ligands (for 9),
N1
Cu
S2
S1
respectively. The s-values [14] for 6, 7, and 9 are ranging from
0.01 to 0.15 confirming a square-pyramidal coordination geometry
at the metal centers with the nitrogen and sulfur donor functions
coordinated in basal positions.
Cl1
For complex 6 (Fig. 1) a Cu–N1 bond length of 2.045(2) Å was
found. The Cu–S separations of 2.3168(6) Å (S1) and 2.3332(7) Å
(S2) involving the two methylthioether groups are nearly of iden-
tical lengths and the measured values fall in the range observed for
the copper(II) complex of a tripodal ligand containing an ethyl-
thioether donor [9]. As expected for a square-pyramidal complex,
the basal chloro ligand Cl2 features a significantly shorter Cu–Cl
bond length (2.2763(7) Å) than the apical ligand chloro ligand
Cl1 (2.4864(7) Å).
Cl2
Fig. 1. Molecular structure of complex 6 (hydrogen atoms have been omitted for
clarity). Selected bond lengths (Å) and angles (°): Cu–S1 2.3168(6), Cu–S2
2.3332(7), Cu–Cl1 2.4864(7), Cu–Cl2 2.2763(7), Cu–N1 2.045(2); S1–Cu–S2
163.76(2), S1–Cu–Cl1 92.04(2), S1–Cu–Cl2 90.08(2), S1–Cu–N1 86.95(5), S2–Cu–
Cl1 102.66(2), S2–Cu–Cl2 93.19(2), S2–Cu–N1 85.36(5), Cl1–Cu–Cl2 103.20(2), Cl1–
Cu–N1 93.32(5), Cl2–Cu–N1 163.31(5).
Complex 7 crystallizes with two molecules in the asymmetric
unit and only one of these is depicted in Fig. 2. These two crystal-
lographically independent molecules feature essentially identical
metric parameters. Apparently due to the greater steric demand
N1
S1
Cu1
S2
NaSMe
SMe
NEt3
DMF
HN
Cl2
SMe
Cl
1
Cl1
ClH⋅HN
Cl
HSBn
Fig. 2. Molecular structure of one of the two independent molecules of 7 in the
asymmetric unit (hydrogen atoms have been omitted for clarity). Selected bond
lengths (Å) and angles (°) for molecule 1 (molecule 2): Cu–S1 2.3625(9) [2.4126(9)],
Cu1–S2 2.3770(9) [2.4308(9)], Cu1–Cl1 2.2629(9) [2.2535(9)], Cu–Cl2 2.4509(8)
[2.4395(8)], Cu–N1 2.005(3) [1.999(3)]; S1–Cu–S2 156.32(3) [158.51(3)], S1–Cu–
Cl1 92.21(3) [93.17(3)], S1–Cu–Cl2 102.45(3) [98.97(3)], S1–Cu–N1 85.77(8)
[83.79(8)], S2–Cu–Cl1 92.63(3) [92.44(3)], S2–Cu–Cl2 99.51(3) [100.25(3)], S2–
Cu–N1 83.63(8) [84.96(8)], Cl1–Cu–Cl2 99.97(3) [101,23(3)], Cl1–Cu–N1 165.13(8)
[163.52(8)], Cl2–Cu–N1 94.85(8) [95.24(8)] .
SBn
SBn
HN
NaOEt
EtOH
2
NaSMe
NEt3
DMF
Br
SMe
SBn
BrH⋅H2N
H2N
SMe
SBn
HN
K2CO3
MeCN
4
5
S
HSBn
3
of the Bz–S groups, the Cu–S distances in 7 (range 2.3625(9)–
Br
2.4308(9) Å) are slightly longer than in
6
(2.3168(6)–
2.3332(7) Å), while the Cu–N distances in 7 (1.999(3)–2.005(3) Å)
are slightly shorter than in 6 (2.045(2) Å).
Scheme 1. Synthesis of the tridentate ligands 1–3.

M. Blomenkemper et al. / Inorganica Chimica Acta 390 (2012) 143–147
145
3. Conclusions
Square-pyramidal copper(II) complexes 6, 7, 9, and 10 with the
tridentate amine/dithioether ligands 1–3 have been prepared from
the ligands and CuCl2 or Cu(NO3)2, respectively. The copper center
in these complexes feature a square-pyramidal coordination geom-
etry with the donor atoms of the tridentate ligands and one coun-
ter ion in the basal positions. The interactions of the copper(II)
center and the apical ligands is weak and not significantly
influenced by the additional donors present. In case of complex
10 an unsymmetrically bridging nitrato ligand coordinating to
the apical positions of two copper(II) centers was observed, con-
firming the weak interaction of square-pyramidal copper(II) to its
apical donor.
N1
O2
O3
Cu S1
S2
N2
O5
N3
O1
O4
O6
Fig. 3. Molecular structure of 9 (hydrogen atoms have been omitted for clarity).
Selected bond lengths (Å) and angles (°): Cu–S1 2.3618(13), Cu–S2 2.3777(13), Cu–
O1 2.244(2), Cu–O4 1.983(2), Cu–N1 2.006(2); S1–Cu–S2 167.33(3), S1–Cu–O1
91.16(6), S1–Cu–O4 91.70(6), S1–Cu–N1 87.35(7), S2–Cu–O1 100.99(6), S2–Cu–O4
93.56(6), S2–Cu–N1 86.56(7), O1–Cu–O4 81.73(8), O1–Cu–N1 102.45(9), O4–Cu–
N1 175.72(9).
4. Experimental
4.1. Materials and methods
All manipulations were carried out under argon using Schlenk
or glovebox techniques. Solvents were dried by standard methods
and freshly distilled prior to use. Elemental analyses were
Complex 9 differs from the previously discussed complexes 6
and 7 by the presence of an unsymmetrically substituted ligand
and the exchange of the chloro ligands for ligands. The molecular
structure of 9 (Fig. 3) shows the coordination of the CuII center
performed with
a Vario EL III Elemental Analyzer at the
by two
g
1-nitrato ligands and the donors of the tridentate ligand
Institut für Anorganische und Analytische Chemie, University of
Münster. N,N-bis(2-benzylmercaptoethyl)amine (2) and 2-ben-
zylmercaptoethylbromide (5) were synthesized as published
previously [8].
3. Equivalent metric parameters of complexes 6, 7 and 9 are simi-
lar. The Cu–S bond lengths for the two different thioether groups
are nearly identical with values of 2.3618(13) Å (S1) and
2.3777(13) Å, respectively.
The dinuclear complex 10 (Fig. 4) consists of two copper(II)
4.2. Synthesis of N,N-bis(2-methylmercaptoethyl)amine (1)
complex fragments connected by an g1 g1
, -l-nitrato ligand which
coordinates in a bridging fashion to both metal ions. As observed
for the analogous mononuclear complex 6, the coordination geom-
etry of both metal centers square-pyramidal exhibiting s-values
A sample of bis(2-chloroethyl)amine hydrochloride (17.85 g,
100 mmol) was dissolved in 50 mL of DMF. To this solution were
added triethylamine (10.12 g, 100 mmol) and sodium methylthiol-
ate (14.02 g, 200 mmol). The reaction mixture was stirred at ambi-
ent temperature for 15 min and subsequently heated for 2 h to
50 °C. After removal of the solvent in vacuo the remaining solid
was extracted with chloroform (3 Â 50 mL). The combined organic
phases were dried over anhydrous sodium sulfate. The solvent was
the removed in vacuo and the oily residue was purified by
distillation (bp 120 °C at 0.03 mbar). Yield: 14.03 g (84.8 mmol,
85 %) of a colorless oil. 1H NMR (200.1 MHz, CDCl3): d 2.92 (t, 4H,
NCH2), 2.56 (t, 4H, SCH2), 2.02 (s, 1H, NH), 1.99 (s, 6H, CH3).
13C{1H} NMR (50.3 MHz, CDCl3): d 50.4 (NCH2), 37.1 (SCH2), 16.5
(CH3). Anal. Calc. for C6H15NS2 (165.32): C, 43.59; H, 9.15; N,
8.47. Found: C, 43.68; H, 8.98; N, 8.62%.
[14] of 0.08 (Cu1) and 0.06 (Cu2), respectively. The metric param-
eters within the two {CuCl(1)} moieties are in good agreement
with the equivalent values observed in complex 6. The apical posi-
tions of both copper(II) centers are occupied by oxygen atoms of
the bridging nitrato ligand. Interestingly, two significantly differ-
ent Cu–O distances (Cu1–O1 2.339(5) Å; Cu2–O3 2.500(7) Å) were
found. We take this observation as an indication for the weak inter-
action between the copper(II) centers and the apical ligands which
might be influenced by intermolecular by crystal packing forces.
4.3. Synthesis of 2-methylmercaptoethylamine (4)
N2
N1
O2
S4
A
sample of 2-bromoethylamine hydrobromide (20.49 g,
100 mmol) was dissolved in 50 mL of DMF. To this were added tri-
ethylamine (10.12 g, 100 mmol) and sodium methylthiolate
(7.01 g, 100 mmol). The reaction mixture was stirred at ambient
temperature for 15 min and subsequently heated for 2 h to 50 °C.
After removal of the solvent in vacuo the remaining solid was ex-
tracted with chloroform (3 Â 50 mL). The combined organic phases
were dried over anhydrous sodium sulfate. The solvent was re-
moved in vacuo and the oily residue was purified by distillation
(bp 80 °C at 0.03 mbar). Yield: 8.51 g (93.3 mmol, 93%) of a color-
less oil. 1H NMR (200.1 MHz, CDCl3): d 3.02 (t, 2H, NCH2), 2.43 (t,
2H, SCH2), 2.10 (s, 2H, NH2), 1.95 (s, 3H, CH3). 13C{1H} NMR
(50.3 MHz, CDCl3): d 44.4 (NCH2), 39.1 (SCH2), 16.6 (CH3). MAL-
DI-MS (TOF, positive ions, m/z): 92 [M+H]+. Anal. Calc. for C3H9NS
(91.18): C, 39.52; H, 9.95; N, 15.36. Found: C, 39.58; H, 9.98; N,
13.62%.
S2
Cu2
Cu1
Cl1
N3
S1
O1
O3
S3
Cl2
Fig. 4. Molecular structure of the complex cation in 10 (hydrogen atoms have been
omitted for clarity). Selected bond lengths (Å) and angles (°): Cu1–S1 2.336(2), Cu1–
S2 2.349(2), Cu1–Cl1 2.226(2), Cu1–O1 2.339(5), Cu1–N1 2.008(5), Cu2–S3
2.332(2), Cu2–S4 2.343(2), Cu2–Cl2 2.237(2), Cu2–O3 2.500(7), Cu2–N2 2.008(6);
S1–Cu1–S2 171.10(7), S1–Cu1–Cl1 91.97(7), S1–Cu1–O1 80.36(14), S1–Cu1–N1
86.4(2), S2–Cu1–Cl1 92.98(8), S2–Cu1–O1 106.18(14), S2–Cu1–N1 87.1(2), Cl1–
Cu1–O1 98.59(13), Cl1–Cu1–N1 166.2(2), O1–Cu1–N1 94.6(2), S3–Cu2–S4
174.52(8), S3–Cu2–Cl2 92.83(8), S3–Cu2–O3 73.41(14), S3–Cu2–N2 87.0(2), S4–
Cu2–Cl2 92.55(8), S4–Cu2–O3 106.46(15), S4–Cu2–N2 87.6(2), Cl2–Cu2–O3
101.8(2), Cl2–Cu2–N2 171.2(2), O3–Cu2–N2 86.6(2),

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M. Blomenkemper et al. / Inorganica Chimica Acta 390 (2012) 143–147
4.4. Synthesis of N,N-(2-benzylmercaptoethyl)(2-
4.6. Synthesis of [{CuCl(1)}2(g1 g1
, -l-NO3)]NO3 (10)
methylmercaptoethyl)amine (3)
A sample of [CuCl2(1)] 6 (78 mg, 0.26 mmol) was dissolved in
acetonitrile (15 mL). To this was added a solution of silver nitrate
(44 mg, 0.26 mmol) in 5 ml of degassed water. The reaction mix-
ture was stirred for 1 h at ambient temperature. The precipitated
AgCl and other insoluble material were removed by filtration.
Upon addition of 20 mL of diethyl ether to the filtrate complex
10 precipitated as a green solid which was collected by filtration
and dried in vacuo. Crystals of 10 suitable for an X-ray diffraction
study were obtained by slow diffusion of diethyl ether into an ace-
tonitrile solution of the complex. Yield: 108 mg (0.17 mmol, 65%)
of a green solid. MALDI-MS (TOF, positive ions, m/z): 653 [M+H]+.
2-Benzylmercaptoethylbromide
5 (17.80 g, 77 mmol) and
potassium carbonate (30 g, 217 mmol) were added successively
to a solution of 2-methylmercaptoethylamine 4 (7.02 g, 77 mmol)
in acetonitrile (150 mL). The resulting suspension was heated for
16 h under reflux. Subsequently, insoluble components were re-
moved by filtration. The clear solution was brought to dryness in
vacuo and compound 3 was purified by distillation (bp 175 °C at
0.05 mbar). Yield: 11.86 g (49.1 mmol, 64%) of a colorless oil. 1H
NMR (200.1 MHz, CDCl3): d 7.10 (m, 5H, CH2C6H5), 3.72 (s, 2H,
CH2C6H5), 2.85–2.40 (m, 8H, NCH2, CH3SCH2, C6H5CH2SCH2), 2.08
(s, 3H, CH3), 1.96 (s, 1H, NH). 13C{1H} NMR (50.3 MHz, CDCl3): d
138.2 (C5H5–Cipso), 128.0 (br, C6H5–C), 50.9 (NCH2), 38.5
(C6H5CH2SCH2), 37.0 (CH3SCH2), 36.2 (C6H5CH2SCH2), 16.6 (CH3).
MALDI-MS (TOF, positive ions, m/z): 242 [M+H]+. Anal. Calc. for
4.7. X-ray diffraction studies
X-ray diffraction data for 6, 7, 9, and 10 were collected at
T = 153(2) K with a Bruker AXS APEX CCD diffractometer equipped
C
12H19NS2 (241.42): C, 59.70; H, 7.93; N, 5.80. Found: C, 56.77;
H, 8.01; N, 5.72%.
with a rotation anode using monochromated Mo K
a radiation
(k = 0.71073 Å). Diffraction data were collected over the full sphere
and were corrected for absorption. Structure solutions were found
with the SHELXS-97 [15] package using direct methods and were re-
fined with SHELXL-97 [16] against all |F2| using first isotropic and la-
ter anisotropic thermal parameters for all non-hydrogen atoms.
Hydrogen atoms were added to the structure models on calculated
positions.
4.5. General procedure for the synthesis of the copper(II) complexes
(6–9)
The copper(II) precursor salt (0.50 mmol) was added as a solid
to a solution of the tridentate ligand (0.50 mmol) in acetonitrile
(6 mL). The reaction mixture was stirred for 16 h at ambient tem-
perature and subsequently filtered. Addition of 20 mL of diethyl
ether to the filtrate led to precipitation of 6–9 as green solids which
were collected by filtration and dried in vacuo. Crystals of 6, 7 and 9
suitable for X-ray diffraction analyses were obtained by slow diffu-
sion of diethyl ether into acetonitrile solutions of the complexes.
4.7.1. Crystal data for [CuCl2(1)] (6)
C6H15NCl2CuS2, M = 299.75 g molÀ1, green crystal, 0.15 Â 0.07
 0.05 mm3, orthorhombic, space group Pbcn, Z = 8, a = 14.228(3),
b = 13.062(3), c = 12.124(3) Å, V = 2253.1(8) Å3,
q
calc = 1.767
= 2.733 mmÀ1
- and
-scans, 24527 measured intensities (4.2° 6 2h 6 60.1°), semiem-
pirical absorption correction (0.685 6 T 6 0.875), 3281 indepen-
g cmÀ3, Mo K
a
radiation (k = 0.71073 Å),
l
, x
u
4.5.1. Synthesis of [CuCl2(1)] (6)
dent (Rint = 0.0497) and 2942 observed intensities (I P 2r(I)),
The complex was prepared from copper(II) chloride (67 mg,
refinement of 169 parameters against |F2| of all measured intensi-
ties with hydrogen atoms on calculated positions. R = 0.0328,
wR = 0.0683, Rall = 0.0396, wRall = 0.0704. The asymmetric unit con-
tains one formula unit of 6.
0.50 mmol) and ligand
1 (83 mg, 0.50 mmol). Yield: 128 mg
(0.43 mmol, 86%) of a green solid. MALDI-MS (TOF, positive ions,
m/z): 301 [M+H]+. UV–Vis (acetonitrile, nm): k = 306, 362, 721.
Anal. Calc. for C6H15NCl2CuS2 (299.75): C, 24.04; H, 5.04; N, 4.67.
Found: C, 24.10; H, 5.22; N, 4.52%.
4.7.2. Crystal data for [CuCl2(2)] (7)
C
18H23NCl2CuS2, M = 451.93 g molÀ1, green crystal, 0.17 Â 0.12
4.5.2. Synthesis of [CuCl2(2)] (7)
 0.04 mm3, monoclinic, space group P21, Z = 4, a = 17.537(2),
The complex was prepared from copper(II) chloride (67 mg,
0.50 mmol) and ligand 2 (159 mg, 0.50 mmol). Yield: 179 mg
(0.40 mmol, 80%) of a green solid. MALDI-MS (TOF, positive ions,
m/z): 453 [M+H]+. UV–Vis (acetonitrile, nm): k = 297, 390, 706.
Anal. Calc. for C18H23NCl2CuS2 (451.93): C, 47.83; H, 5.13; N, 3.10.
Found: C, 45.72; H, 4.16; N, 3.38%.
b = 6.7240(8), c = 17.927(2) Å, b = 107.533(3)°, V = 2015.7(4) Å3,
q
calc = 1.489 g cmÀ3, Mo K
a
radiation (k = 0.71073 Å),
l = 1.556
mmÀ1
, x- and u-scans, 23551 measured intensities (2.4° 6 2h 6
60.1°), semiempirical absorption correction (0.778 6 T 6 0.940),
11373 independent (Rint = 0.0479) and 9558 observed intensities
(I P 2r
(I)), refinement of 441 parameters against |F2| of all mea-
sured intensities with hydrogen atoms on calculated positions.
R = 0.0433, wR = 0.0841, Rall = 0.0556, wRall = 0.0883. The asymmet-
ric unit contains two independent molecule of 7.
4.5.3. Synthesis of [CuCl2(3)] (8)
The complex was prepared from copper(II) chloride (67 mg,
0.50 mmol) and ligand 3 (121 mg, 0.50 mmol). Yield: 134 mg
(0.36 mmol, 72%) of a green solid. MALDI-MS (TOF, positive ions,
m/z): 377 [M+H]+. UV–Vis (acetonitrile, nm): k = 296, 383, 725.
Anal. Calc. for C12H19NCl2CuS2 (375.87): C, 38.35; H, 5.10; N, 3.73.
Found: C, 37.92; H, 4.66; N, 3.48%.
4.7.3. Crystal data for [Cu(NO3)(3)] (9)
C
12H19N3CuO6S2, M = 428.96 g molÀ1, green crystal, 0.32 Â 0.30
 0.03 mm3, monoclinic, space group P21/c, Z = 1, a = 8.118(4),
b = 11.563(6), c = 19.395(10) Å, b = 101.568(10), V = 1783.6(15) Å3,
q
calc = 1.597 g cmÀ3, Mo K
mmÀ1
and
a
radiation (k = 0.71073 Å),
l = 1.491
,
x
-
u-scans, 19842 measured intensities (4.1° 6
4.5.4. Synthesis of [Cu(NO3)2(3)] (9)
2h 6 60.3°), semiempirical absorption correction (0.647 6 T 6
The complex was prepared from copper(II) nitrate dihydrate
(112 mg, 0.50 mmol) and ligand 3 (121 mg, 0.50 mmol). Yield:
175 mg (0.41 mmol, 82%) of a green solid. MALDI-MS (TOF, positive
ions, m/z): 430 [M+H]+. Anal. Calc. for C12H19N3CuO6S2 (428.96): C,
33.60; H, 4.46; N, 9.80. Found: C, 33.72; H, 4.26; N, 9.48%.
0.957), 5198 independent (Rint = 0.0842) and 3254 observed inten-
sities (I P 2r
(I)), refinement of 222 parameters against |F2| of all
measured intensities with hydrogen atoms on calculated positions.
R = 0.0475, wR = 0.0889, Rall = 0.0878, wRall = 0.0979. The asymmet-
ric unit contains one molecule of 9.

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147
4.7.4. Crystal data for [{CuCl(1)}2(g1 g1
, -l-NO3)]NO3 (10)
(b) L.M. Berreau, Eur. J. Inorg. Chem. (2006) 273.
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C
12H30N4Cl2Cu2O6S4, M = 652.62 g molÀ1, green crystal, 0.18 Â
0.07 Â 0.05 mm3, triclinic, space group P1, Z = 1, a = 6.829(2), b =
(c) F.E. Hahn, C. Ochs, T. Lügger, R. Fröhlich, Inorg. Chem. 43 (2004) 6101;
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1030;
(i) S.C. Davies, D.J. Evans, D.L. Hughes, M. Konkol, R.L. Richards, J.R. Sanders, P.
Sobota, J. Chem. Soc., Dalton Trans. (2002) 2473;
7.664(2), c = 12.185(4) Å,
102.986(7)°, V = 608.6(3) Å3,
a
q
= 98.886(7), b = 95.287(6),
c =
calc = 1.781 g cmÀ3, Mo K
- and -scans, 6625 measured
intensities (3.4° 6 2h 6 58.0°), 5825 independent (Rint = 0.0763)
a radiation
(k = 0.71073 Å),
l
= 2.345 mmÀ1
,
x
u
and 3941 observed intensities (I P 2r(I)), refinement of 275
parameters against |F2| of all measured intensities with hydrogen
atoms on calculated positions. R = 0.0540, wR = 0.0996,
Rall = 0.0803, wRall = 0.1055. The unit cell contains one molecule
of 10.
(j) F.E. Hahn, T.J. McMurry, A. Hugi, K.N. Raymond, J. Am. Chem. Soc. 122 (1990)
1854.
4.7.5. Crystal data for [(Cu(1)Cl)2(
l-NO3)]NO3 (10)
C12H30Cl2Cu2N4O6S4, M = 652.66, triclinic, P1, Z = 1, a = 6.829(2),
[7] (a) A.M. Dittler-Klingemann, F.E. Hahn, Inorg. Chem. 35 (1996) 1996;
(b) A.M. Dittler-Klingemann, C. Orvig, F.E. Hahn, F. Thaler, C.D. Hubbard, R. van
Eldik, S. Schindler, I. Fábián, Inorg. Chem. 35 (1996) 7798;
(c) F. Thaler, C.D. Hubbard, F.W. Heinemann, R. van Eldik, S. Schindler, I. Fábián,
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(d) C. Ochs, F.E. Hahn, T. Lügger, Eur. J. Inorg. Chem. (2001) 1279.
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(2011) 76.
b = 7.664(2), c = 12.185(4) Å,
a = 98.886(7), b = 95.287(6), c =
102.986(7)°, V = 608.6(3) Å3, 6625 measured reflections, 5825 un-
ique reflections (Rint = 0.0763), R = 0.0540, wR = 0.1055 for 3941
contributing reflections [I P 2r(I)].
Appendix A. Supplementary material
[9] K.J. Tubbs, A.L. Fuller, B. Bennett, A.M. Arif, L.M. Berreau, Inorg. Chem. 42
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[10] W. Rammal, H. Jamet, C. Philouze, J.-L. Pierre, E. Saint-Aman, C. Belle, Inorg.
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Inorg. Chem. 31 (1992) 3796;
CCDC 813341 (6), 813342 (7), 883343 (9) and 813344 (10) con-
tain the supplementary crystallographic data for this paper. These
data can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.ica.2012.04.023.
(b) S.G. Mastrostamatis, M.S. Papadopoulos, I.C. Pirmettis, E. Paschali, A.D.
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