Preparation and characterization of rhenium(I) complexes with thiosemicarbazone ligands derived from resorcinol

Article abstract of DOI:10.1016/j.poly.2013.08.038

New neutral tricarbonylrhenium(I) complexes with bidentate thiosemicarbazone ligands derived from resorcinol have been prepared. Ligands were obtained by condensation reactions of 2,4-dihydroxybenzaldehyde (dhb) and 2,4-dihydroxyacetophenone (dha) with th

Full text of DOI:10.1016/j.poly.2013.08.038

Polyhedron 65 (2013) 221–228
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Preparation and characterization of rhenium(I) complexes
with thiosemicarbazone ligands derived from resorcinol
a
a
b
a,
⇑
Ara Núñez-Montenegro , Rosa Carballo , Ulrich Abram , Ezequiel M. Vázquez-López
a
Departamento de Química Inorgánica, Universidade de Vigo, E-36300 Vigo, Galicia, Spain
Institute of Chemistry and Biochemistry, Freie Universität Berlin, D-14195 Berlin, Germany
b
a r t i c l e i n f o
a b s t r a c t
Article history:
New neutral tricarbonylrhenium(I) complexes with bidentate thiosemicarbazone ligands derived from
resorcinol have been prepared. Ligands were obtained by condensation reactions of 2,4-dihydroxy-
benzaldehyde (dhb) and 2,4-dihydroxyacetophenone (dha) with thiosemicarbazide derivatives. The
metal complexes have been characterized by elemental analysis, mass spectrometry, spectroscopic
Received 20 May 2013
Accepted 9 August 2013
Available online 21 August 2013
1
methods (IR, H NMR) and the crystal structures for eight of these compounds have been elucidated.
Keywords:
Rhenium
Tricarbonyl complexes
Resorcinol derivatives
X-ray
The Re(I) metal centers are coordinated through the azomethine nitrogen and the sulfur atoms
6
establishing five-membered chelate rings (
labilization of the halogen produces the formation of the dimeric complex [Re
j
-S,N(3)). The deprotonation of the ligand HL and the
6
2
(L )
2 6
(CO) ] by
Re–S–Re bridges, where S is the thiolate sulfur atom from a
ligand.
j-S,N(3)-bidentate thiosemicarbazonate
Thiosemicarbazone ligands
Ó 2013 Elsevier Ltd. All rights reserved.
1
. Introduction
hydrogen bond with one of the nitrogen atoms of the TSC
chain, meanwhile the other hydroxyl group will be responsible
for a series of intermolecular interactions between neighbor
molecules.
In this work we intend to analyze the presence of competitive
hydrogen bonding and the effect of the coordination of these
ligands to rhenium(I) on their intramolecular interactions.
The chemistry of rhenium and technetium has been investi-
gated extensively due to the significance of these metals in the
development of radiopharmaceuticals for imaging and/or radio-
therapy [1,2]. Rhenium exhibits similar chemical properties to
technetium and is often used as a non-radioactive alternative for
large scale synthesis and structural characterization. The investiga-
tion of new chelating agents that bind rhenium/technetium is a
priority in the design of specific radiopharmaceuticals. In the
recent years, the development of a normal pressure preparation
for [M(H
high yields and purity from saline solutions of MO
2
. Experimental
+
2
O)
3
(CO)
3
] (M = Re, Tc), which yields the complexes in
À
2.1. Materials and methods
4
, has opened
the possibility of using these metallic cores in radiotherapy and
radioimaging [3].
In previous papers, we reported the synthesis and character-
ization of S,N-bidentate ligands derived from thiosemicarbazones
All solvents used for synthesis were dried over appropriate
drying agents, degassed using a vacuum line and distilled under
an Ar atmosphere [9]. Ligands HL were synthesized following
published procedures [4]. The adducts [ReX(CO)
synthesized following Farona and Kraus’ published methods
10] from the corresponding [ReX(CO) ] complexes [11]. Elemen-
tal analyses were carried out on a Fisons EA-1108. Melting points
mp) were determined on a Gallenkamp MFB-595 and they are
3 3 2
(CH CN) ] were
(
[
TSC) which form stable six-coordinated rhenium(I) complexes
4,5]. In our investigations about new TSC complexes of rhe-
[
5
nium(I) [8], we have found that thiosemicarbazones derived from
resorcinol are excellent candidates due to their supramolecular
chemistry [6,7]. Up to now, our work is centered on TSC ligands
derived from 2,4-dihydroxybenzaldehyde and 2,4-dihydroxyace-
tophenone as resorcinol derivatives where one ortho-hydroxyl
group has the suitable orientation to establish an intramolecular
(
uncorrected. Mass spectra were recorded on a VG Autospec
Micromass spectrometer operating under FAB conditions (nitro-
benzyl alcohol matrix) with adducts and on a Hewlett-Packard
5
989A spectrometer operating under ESI conditions for the
isolated dimer. Infrared spectra were recorded from KBr pellets
1
⇑
Corresponding author. Tel.: +34 986812319.
E-mail address: ezequiel@uvigo.es (E.M. Vázquez-López).
on a Bruker Vector 22FT. The H NMR spectra were obtained on
a Bruker ARX-400 spectrometer.
0
277-5387/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2013.08.038

2
22
A. Núñez-Montenegro et al. / Polyhedron 65 (2013) 221–228
+
+
+
2
2
.2. Synthesis
(%)]: 561 (24) [M , 482 (100) [MÀBr] , 453 (25) [MÀ(Br, CO)] ,
+
+
4
25 (8) [MÀ(Br, 2CO)] , 398 (23) [MÀ(Br, 3CO)] . IR data (KBr,
À1
.2.1. Synthesis of the ligands
cm ): 3542m, 3429m, 3318m
m
(NH, OH); 2023vs, 1896vs
To a mixture of an aqueous solution (15 mL) of thiosemicarba-
m
(COfac); 1616s
m
(C@N); 727w
m
(C@S).
(HL )] (2a): Yield: 134 mg (84.69%). M.p.: 227 °C. Anal.
11ClN SRe (530.97): C, 27.1; H, 2.1; N, 7.9; S, 6.0.
Found: C, 27.3; H, 1.9; N, 7.2; S, 5.5%. Mass spectrum [m/z (%)]: 531
2
zide (10 mmol) and a methanol solution (30 mL) of dhb or dha
10 mmol) are added three drops of H SO4(conc). The reaction mix-
tures are heated under reflux for 2 h and cooled to r.t. The resulting
solids are filtered off and vacuum dried over KOH/CaCl
[ReCl(CO)
3
(
2
Calc. for C12
H
3 5
O
+
+
+
2
.
(16) [M] , 496 (54) [MÀCl] , 467 (14) [MÀ(Cl, CO)] , 411(11) [MÀ(Cl,
1
1
2
+
À1
HL (R = R = H). Pale orange solid. Yield: 78.3%. M.p.: 204 °C.
Anal. Calc. for C S (211.04): C, 45.5; H, 4.3; N, 19.9; S,
5.2. Found: C, 45.7; H, 4.4; N, 19.9; S, 15.6%. Mass spectrum
m/z (%)]: 212 (20) [M] . IR data (KBr, cm ): 3477m, 3336m,
171m (NH, OH); 1632s (C@N); 741w (C@S).
HL (R = H, R = Me). Orange crystalline solid. Yield: 72.3%.
M.p.: 202 °C. Anal. Calc. for C S (225.06): C, 47.9; H, 4.9;
N, 18.7; S, 14.2. Found: C, 47.4; H, 5.0; N, 18.7; S, 14.9%. Mass spec-
3CO)] . IR data (KBr, cm ): 3549m, 3383m, 3312m
2028vs, 1900vs (COfac); 1592s (C@N); 727w (C@S).
(HL )] (2b): Yield: 125 mg (82.52%). M.p.: 216 °C.
Anal. Calc. for C12 11BrN SRe (574.92): C, 25.1; H, 1.9; N, 7.3;
S, 5.6. Found: C, 25.3; H, 2.1; N, 7.1; S, 5.0%. Mass spectrum [m/z
m(NH, OH);
8
H
9
N
3
O
2
m
m
m
2
1
[
3
[ReBr(CO)
3
+
À1
H
3 5
O
m
m
m
2
1
2
+
+
(%)]: 572 (8.4) [M] , 496 (27.6) [MÀBr] , 467 (14.7) [MÀ(Br,
+
+
À1
9
H
11
N
3
O
2
CO)] , 411 (11.9) [MÀ(Br, 3CO)] . IR data (KBr, cm ): 3546m,
3383m, 3248m (NH, OH); 2024vs, 1893vs (COfac); 1571s
(C@N); 726w (C@S).
[ReCl(CO) (HL )] (3a): Yield: 120 mg (69.23%). M.p.: 224 °C. Anal.
Calc. for C17 13ClN SRe (592.98): C, 34.4; H, 2.2; N, 7.1; S, 5.4.
Found: C, 34.3; H, 2.2; N, 7.0; S, 5.2%. Mass spectrum [m/z (%)]: 593
m
m
+
À1
trum [m/z (%)]: 226 (100) [M] . IR data (KBr, cm ): 3456m,
m
m
3
3
379m, 3288m
m
(NH, OH); 1627s
m
(C@N); 742w
HL (R = H, R = Ph). Yellow-green solid. Yield: 72.4%. M.p.:
86 °C. Anal. Calc. for C14 S (287.07): C, 58.5; H, 4.6; N,
4.6; S, 11.1. Found: C, 57.9; H, 4.6; N, 14.7; S, 10.6%. Mass spectrum
m
(C@S).
3
3
1
2
H
3 5
O
1
1
[
13 3 2
H N O
+
+
+
(14) [M] , 558 (45) [MÀCl] , 529 (15) [MÀ(Cl, CO)] , 473 (10) [MÀ(Cl,
+
À1
+
À1
m/z (%)]: 288 (100) [M] . IR data (KBr, cm ): 3554m, 3420m
OH); 1629s (C@N); 744w (C@S).
HL (R = Me, R = H). White crystalline solid. Yield: 74.6%. M.p.:
26 °C. Anal. Calc. for C S (225.06): C, 48.0; H, 4.9; N, 18.7;
S, 14.2. Found: C, 48.1; H, 4.9; N, 18.5; S, 13.8%. Mass spectrum
m
(NH,
3CO)] . IR data (KBr, cm ): 3536m, 3384m, 3284m
2027vs, 1907vs (COfac); 1571s (C@N); 726w (C@S).
(HL )] (3b): Yield: 104 mg (62.40%). M.p.: 211 °C. Anal.
13BrN SRe (636.93): C, 32.0; H, 2.1; N, 6.6; S, 5.0.
Found: C, 32.3; H, 1.9; N, 6.4; S, 4.8%. Mass spectrum [m/z (%)]: 637
m(NH, OH);
m
m
m
3
m
m
4
1
2
[ReBr(CO)
Calc. for C17
3
2
H
9 11
N
3
O
2
H
3 5
O
+
À1
+
+
+
[
3
m/z (%)]: 226 (74) [M] . IR data (KBr, cm ): 3385m, 3298m,
165m (NH, OH); 1630s (C@N); 743w (C@S).
HL (R = Me, R = Me). Yellow crystalline solid. Yield: 85.0%.
M.p.: 212 °C. Anal. Calc. for C10 S (239.07): C, 50.2; H, 5.5;
N, 17.6; S, 13.4. Found: C, 50.0; H, 5.4; N, 17.5; S, 13.4%. Mass spec-
(16) [M] , 558 (43) [MÀBr] , 529 (15) [MÀ(Br, CO)] , 473 (10)
+
À1
m
m
m
[MÀ(Br, 3CO)] . IR data (KBr, cm ): 3541m, 3404m, 3283m
OH); 2026vs, 1923vs, 1892vs (COfac); 1570s (C@N); 729w (C@S).
(HL )] (4a): Yield: 125 mg (79.3%). M.p.: 211 °C. Anal.
11ClN SRe (530.97): C, 27.1; H, 2.1; N, 7.9; S, 6.0.
Found: C, 27.3; H, 1.9; N, 7.8; S, 5.9%. Mass spectrum [m/z (%)]:
m(NH,
5
1
2
m
m
m
4
H
13
N
3
O
2
[ReCl(CO)
Calc. for C12
3
H
3 5
O
+
À1
trum [m/z (%)]: 240 (99) [M] . IR data (KBr, cm ): 3344m, 3238m,
175m (NH, OH); 1628s (C@N); 745w (C@S).
HL (R = Me, R = Ph). Yellow solid. Yield: 73.3%. M.p.: 165 °C.
+
+
+
3
m
m
m
531 (18) [M] , 496 (100) [MÀCl] , 467 (15) [MÀ(Cl, CO)] , 439
6
1
2
+
+
(12) [MÀ(Cl, 2CO)] , 411 (20) [MÀ(Cl, 3CO)] . IR data (KBr,
À1
Anal. Calc. for C15
H
15
N
3
O
2
S (301.09): C, 59.8; H, 5.0; N, 13.9; S,
cm ): 3449m, 3275m, 3185m
m
(NH, OH); 2026vs, 1926vs,
1
0.6. Found: C, 59.2; H, 5.0; N, 13.8; S, 10.2%. Mass spectrum
1893vs
[ReBr(CO)
Calc. for C12
Found: C, 25.3; H, 1.9; N, 7.5; S, 5.9%. Mass spectrum [m/z (%)]:
m
(COfac); 1615s
m
(C@N); 727w
(HL )] (4b): Yield: 99 mg (64.9%). M.p.: 199 °C. Anal.
11BrN SRe (574.92): C, 25.1; H, 1.9; N, 7.3; S, 5.6.
m(C@S).
+
À1
4
[m/z (%)]: 302 (100) [M] . IR data (KBr, cm ): 3357m, 3267m
3
m(NH, OH); 1631s
m
(C@N); 747w
m
(C@S).
H
3 5
O
n
+
+
+
2
.2.2. Synthesis of rhenium(I) adducts fac-[ReX(CO)
3
(HL )]
HL dissolved in acetone (5 mL) is added drop-wise to a stirred
solution of fac-[ReX(CO) (CH CN) ] (X = Cl, Br) in acetone (5 mL).
575 (23) [M] , 496 (85) [MÀBr] , 467 (17) [MÀ(Br, CO)] , 439 (9)
n
+
+
À1
[MÀ(Br, 2CO)] , 411 (18) [MÀ(Br, 3CO)] . IR data (KBr, cm ):
3446m, 3254m, 3161m (NH, OH); 2024vs, 1919vs, 1894vs
(COfac); 1612s (C@N); 735w (C@S).
(HL )] (5a): Yield: 146 mg (90.1%). M.p.: 209 °C. Anal.
13ClN SRe (544.98): C, 28.6; H, 2.4; N, 7.7; S, 5.9.
Found: C, 28.3; H, 2.1; N, 7.8; S, 5.3%. Mass spectrum [m/z (%)]:
3
3
2
m
The mixture is stirred at r.t. for 1.5 h, whereupon the color changes
from colorless to yellow. For the synthesis of the dhb derivatives,
the solvent is removed in vacuum and dichloromethane is added.
A yellow precipitate deposits within a few minutes. Yellow single-
m
m
m
5
[ReCl(CO)
3
Calc. for C13
H
3 5
O
1
3
+
+
+
crystals of [ReBr(CO)
3
(HL )]ÁH
2
O (1bÁH
2
O) and [ReBr(CO)
3
(HL )]
545 (9) [M] , 510 (38) [MÀCl] , 481 (8) [MÀ(Cl, CO)] , 425 (9)
+
À1
(3b) suitable for X-ray diffraction are obtained directly from the
[MÀ(Cl, 3CO)] . IR data (KBr, cm ): 3382m, 3265m
2023vs, 1924vs, 1898vs (COfac); 1594s (C@N); 726w
(HL )] (5b): Yield: 140 mg (90.6%). M.p.: 202 °C. Anal.
13BrN SRe (588.93): C, 26.5; H, 2.2; N, 7.1; S, 5.4.
Found: C, 26.3; H, 2.1; N, 7.3; S, 5.3%. Mass spectrum [m/z (%)]:
m
(NH, OH);
m(C@S).
mother liquor by slow evaporation. For the synthesis of the dha
derivatives, some drops of diethylether are added and the color of
the solution immediately turns brown-yellow. The solution is kept
in the fridge and a pale-yellow precipitate deposits within a few
days. Colorless single-crystals of [ReCl(CO)
m
m
5
[ReBr(CO)
Calc. for C13
3
H
3 5
O
4
+
+
+
3
(HL )]Á(CH
3
)
2
COÁ
589 (9) [M] , 510 (29) [MÀBr] , 481 (7) [MÀ(Br, CO)] , 425 (6)
5
+
À1
(
(
CH
CH
3
CH
CH
2
)
)
2
O
(4aÁ(CH
3
)
CH
2
COÁ(CH
3
CH
)
2 2
O) and [ReBr(CO)
O) suitable for X-ray diffraction are
3
(HL )]Á
[MÀ(Br, 3CO)] . IR data (KBr, cm ): 3393m, 3265m
2024vs, 1927vs, 1903vs (COfac); 1591s (C@N); 728w
(HL )] (6a): Yield: 119 mg (66.9%). M.p.: 205 °C. Anal.
15ClN SRe (607.00): C, 35.6; H, 2.5; N, 6.9; S, 5.3.
m
(NH, OH);
m(C@S).
3
2
2
O (5bÁ(CH
3
2
)
2
m
m
6
obtained directly from the mother liquor after several days in the
fridge.
ReCl(CO)
Calc. for C11
Found: C, 25.9; H, 1.9; N, 7.8; S, 6.0%. Mass spectrum [m/z (%)]: 517
[ReCl(CO)
3
Calc. for C18
H
3 5
O
1
[
3
(HL )] (1a): Yield: 131 mg (85.06%). M.p.: 198 °C. Anal.
Found: C, 35.1; H, 2.4; N, 6.9; S, 5.5%. Mass spectrum [m/z (%)]:
+
+
+
H
9
3
ClN O
5
SRe (516.95): C, 25.6; H, 1.8; N, 8.1; S, 6.2.
607 (14) [M] , 572 (60) [MÀCl] , 443 (15) [MÀ(Cl, CO)] , 515 (4)
+
+
À1
[MÀ(Cl, 2CO)] , 487 (15) [MÀ(Cl, 3CO)] . IR data (KBr, cm ):
3521m, 3422m, 3389m (NH, OH); 2028vs, 1930vs, 1899vs
(COfac); 1617s (C@N); 725w (C@S).
(HL )] (6b): Yield: 96 mg (56.5%). M.p.: 196 °C. Anal.
15BrN SRe (650.95): C, 33.2; H, 2.3; N, 6.5; S, 4.9.
Found: C, 33.6; H, 2.4; N, 6.2; S, 4.6%. Mass spectrum [m/z (%)]:
+
+
+
(
6) [M] , 482 (18) [MÀCl] , 453 (4) [MÀ(Cl, CO)] . IR data (KBr,
m
À1
cm ): 3540m, 3433m
m(NH, OH); 2026vs, 1896vs
m
(COfac); 1613s
m
m
m
6
m
(C@N); 730w
ReBr(CO) (HL )] (1b): Yield: 127 mg (85.23%). M.p.: 216 °C.
Anal. Calc. for C11 BrN SRe (560.90): C, 23.5; H, 1.6; N, 7.5; S,
.7. Found: C, 23.2; H, 1.9; N, 7.2; S, 5.5%. Mass spectrum [m/z
m
(C@S).
[ReBr(CO)
3
1
[
3
Calc. for C18
H
3 5
O
H
9
3 5
O
+
+
+
5
651 (7) [M] , 572 (100) [MÀBr] , 443 (28) [MÀ(Br, CO)] , 515 (6)

A. Núñez-Montenegro et al. / Polyhedron 65 (2013) 221–228
223
À1
+
+
[
MÀ(Br, 2CO)] , 487 (28) [MÀ(Br, 3CO)] . IR data (KBr, cm ):
3
551m, 3443m, 3252m
m
(NH, OH); 2028vs, 1918vs
m(COfac);
1
615 m
m
(C@N); 727w
m
(C@S).
6
2
.2.3. Synthesis of [Re
2
(L )
2
(CO)
6
]
6
[
Re
2 2 6
(L ) (CO) ] (6c) could only be prepared starting from the bro-
mine derivative. [ReBr(CO)
6
3
(HL )] (6b) (98 mg, 0.15 mmol) was
suspended in 10 mL of dry methanol and NaOMe (8 mg, 0.15 mmol)
was added. The yellow mixture was refluxed for 8 h. During this
time, a white solid precipitated from the solution. This product
was separated by filtration, the volume of the mother liquor was re-
duced in vacuum and after that some diethylether was added. A
brown-green solid precipitated, which was filtered off, vacuum
dried and then crystallized from DMSO to obtain large yellow crys-
tals. Another amount of yellow crystals could be obtained by slow
evaporation of the mother liquor after several days at r.t.
We have also obtained other dimer crystals: 5c, by slow evapo-
ration of the mother liquor of 5a, and crystals of 5d, which were
grown as a byproduct from 5b, resulting from the substitution of
the 2,4-dihydroxyacetophenone phenyl ring by an acetone
molecule.
n
Attempts to obtain the corresponding [Re
2
(L )
2
6
(CO) ] (n = 1–5)
complex were not successful.
6
[
Re
for C36
C, 37.4; H, 2.5; N, 7.4; S, 5.4%. Mass spectrum [m/z (%)]: 1141 (62)
2
(L )
2
(CO)
6
] (6c): Yield: 42 mg (39.6%). M.p.: 188 °C. Anal. Calc.
H
28
N
6
O
10
S
2
Re (1142.04): C, 37.8; H, 2.5; N, 7.4; S, 5.6. Found:
2
+
À1
[
M] . IR data (KBr, cm ): 3541m, 3427m, 3327m
m(NH, OH);
2
017vs, 1928vs, 1878s
m(COfac); 1616s m(C@N); 740w m(C@S).
2.3. X-ray crystallography
Crystallographic data were collected on a Bruker SMART CCD-
000 diffractometer at 293 and 273 K using graphite monochro-
1
mated Mo K
a radiation (k = 0.71073 Å), and were corrected for
Lorentz, polarization and absorption effects [12]. The structures
were solved by direct methods using the program SHELXS97. All
2
non-hydrogen atoms were refined on F with anisotropic thermal
parameters using SHELXL97 [12]. Hydrogen atoms were inserted at
calculated positions and refined as riders. Graphics were produced
with PLATON [13] and MERCURY [14]. Crystallographic data collection
and refinement parameters are listed in Table 1.
3
. Results and discussion
3.1. Synthesis and spectroscopy studies
n
The thiosemicarbazone ligands (HL , Scheme 1) derived from
resorcinol were synthesized by Schiff base condensation using
the corresponding thiosemicarbazide derivatives and 2,4-dihy-
droxybenzaldehyde or 2,4-dihydroxyacetophenone following liter-
ature procedures [4].
Reactions of these ligands with fac-[ReX(CO)
Br) yielded twelve adducts with general formula [ReX(CO)
X = Cl, Br; n = 1–6) (Scheme 1). These compounds were isolated
3 3 2
(CH CN) ] (X = Cl,
n
3
(HL )]
(
as air stable solids, which are moderately soluble in alcohols and
other organic solvents.
Elemental analysis and mass spectrometry confirmed a compo-
n
sition of [ReX(CO)
3
(HL )]. All the mass spectra contain signals
corresponding to the molecular ion, although the peaks due to
+
the species [MÀX] are more intense.
In IR spectra, facial geometry around the rhenium atom is
strongly suggested by the three strong
the two high energy bands collapsed) in the 1878–2028 cm
m
(CO) bands (sometimes
À1
range. The C@N and C@S stretching modes are assigned, respec-
À1
tively, to the strong bands between 1627 and 1632 cm and the

2
24
A. Núñez-Montenegro et al. / Polyhedron 65 (2013) 221–228
X
R1
[ReX(CO)
acetone, r.t
3 3 2
(CH CN) ]
NHR2
H
N
OC
OC
S
N
HO
S
N
Re
NH
NHR2
OH
CO
R1
HO
OH
HLn
n
[ReX(CO) (HL )]
3
n in
HL
R1
H
R2
H
n
n in
HL
X
n in
HL
X
n
n
1
Cl 4a
Br 4b
Cl
1
a
1
4
2
3
4
5
6
H
H
Me
Ph
H
1b
2a
2b
3a
3b
1
2
2
3
3
4
5
5
6
6
Br
Cl
Br
Cl
Br
Cl
5a
Me
Br 5b
Cl 6a
Br 6b
Me Me
Me Ph
Scheme 1. Synthesis of the rhenium(I) adducts.
Table 2
1
6
H NMR spectra data (ppm) in acetone-d . (see number scheme in molecular structures).
N(1)–H
N(1)–R
N(2)–H
C(2)–H
O(1)–H
O(2)–H
C(5)–H
C(7)–H
C(8)–H
HL1
7.55s (2)
8.02s (2)
7.99s (2)
7.90s (1)
8.39s (1)
8.11s (1)
9.41s (1)
10.05s (1)
10.08s (1)
7.25s (2)
8.34s (2)
8.16s (2)
7.57s (1)
8.61s (1)
8.40s (1)
9.20s (1)
10.36s (1)
10.27s (1)
8.68s (1)
–
–
–
10.26s (1)
12.17s (1)
12.17s (1)
10.18s (1)
11.80s (1)
11.90s (1)
10.51s (1)
12.21s (1)
12.21s (1)
9.60s (1)
11.06s (1)
11.00s (1)
9.32s (1)
10.85s (1)
10.82s (1)
9.65s (1)
11.05s (1)
11.02s (1)
–
8.32s(1)
8.67s(1)
8.62s(1)
8.30s (1)
8.56s (1)
8.67s (1)
8.42s (1)
8.74s (1)
8.76s (1)
2.40s (3)
2.60s (3)
2.55s (3)
2.30s (3)
2.57s (3)
2.57s (3)
2.21s (3)
2.59s (3)
2.60s (3)
2.80d (3)
9.45s (1)
9.34s (1)
9.30s (1)
9.40s (1)
9.33s (1)
9.34s (1)
9.60s (1)
9.37s (1)
8.84s (1)
9.17s (1)
9.13s (1)
8.80s (1)
9.13s (1)
9.17s (1)
8.87s (1)
9.23s (1)
9.19s (1)
8.70s (1)
8.72s (1)
8.68s (1)
8.64s (1)
8.76s (1)
8.70s (1)
8.56s (1)
6.38d (1)
6.49s (1)
6.46s (1)
6.38d (1)
6.35s (1)
6.49s (1)
6.43d (1)
6.44d (1)
6.50d (1)
6.33d (1)
6.44s (1)
6.43s (1)
6.28d (1)
6.47s (1)
6.42s (1)
6.15d (1)
6.43s (1)
6.40s (1)
6.51s (1)
6.42dd (1)
6.55dd (1)
6.53dd (1)
6.43dd (1)
6.41dd (1)
6.56dd (1)
6.45dd (1)
6.51dd (1)
6.58dd (1)
6.38dd (1)
6.48d (1)
6.45s (1)
6.33dd (1)
6.49d (1)
6.48d (1)
6.19dd (1)
6.46d (1)
6.45d (1)
6.59dd (1)
7.32d (1)
8.22d (1)
8.08d (1)
7.43d (1)
8.08d (1)
8.09d (1)
7.48d (1)
8.15d (1)
8.11d (1)
7.47d (1)
7.20dd (1)
7.20dd (1)
7.27d (1)
7.20dd (1)
7.20dd (1)
7.25d (1)
7.12d (1)
7.18dd (1)
7.26d (1)
1
1
HL
2
2
HL
3
3
HL
4
4
HL
a
b
2
3
4
5
6
3.13d (3)
3.04d (3)
3.17d (3)
7.69d (2)7.36t (2)7.17t (1)
7.39m (5)
7.40m (5)
–
–
–
3.20s (3)
3.20d (3)
3.19d (3)
7.47d (2)7.12t (2)6.94t (1)
7.51d (2)7.43t (2)7.29t (1)
7.53d(2)7.47t (2)6.94t (1)
7.73d (2) 7.35t (2) 7.06t (1)
a
b
a
b
9.31s (1)
11.58s (1)
a
b
8.88s (0.5) 8.59s (0.5)
8.84s (0.5) 8.57s (0.5)
11.47s (1)
8.87s (0.5) 8.72s (0.5)
8.86s (0.5) 8.59s (0.5)
11.75s (1)
8.94s(0.5)8.65s(0.5)
8.74s(0.5)8.61s(0.5)
8.92s (0.5)
5
5
HL
a
b
6
6
6
a
b
c
8.81s(0.5)8.75s(0.5)
8.73s(0.5)8.72s(0.5)
8.49s(0.5)
À1
weak bands between 741 and 745 cm in the free ligands spectra
Except for N–H and O–H groups, the signals in the adduct
spectra are shifted to low field (around 0.1–1 ppm) with re-
spect to those in the spectra of the free ligands as previously
observed [4,5]. Thus, the N(2)–H hydrogen atom is strongly
deshielded (between 1.5 and 2 ppm) while the O–H signals
À1
are shifted around 20 cm by coordination.
1
Most of the assignments of the H NMR spectra in acetone-d
6
(Ta-
ble 2) are based on results reported before for other rhenium(I) thio-
semicarbazone complexes (see [4,5] and references therein). The
N–H and O–H groups in the free ligand display signals in the
4
–6
are slightly shifted or approached themselves in HL
deriva-
7
–12 ppm range that disappear when D
2
O is added to the solution.
tives. This is due to two different factors; the deshielding
caused by the metal coordination and, consequently, the break-
ing of the intramolecular O(1)–HÁ Á ÁN(3) bond by the formation
of the S,N(3) chelating ring. Again, there are substantial differ-
ences in the behavior of both ligand adducts. In the complexes
The proper assignments of the signals for these groups have been pro-
ven by N HSQC experiments (Figure S1). In the ligands derived from
1
5
1
–3
dhb (HL ) the most deshielded signals (between 10.18 and
0.51 ppm) are due to N(2)–H groups. This is in contrast with the
1
4
–6
1–3
dha derivatives (HL ) where the signals of this groups sites between
.30 and 10.65 ppm. We assign the O(1)–H groups to the most
of the HL , both signals are centered around 9.2 ppm, while in
4
–6
9
HL , the deshielded O–H group is splitted in two signals with
equivalent integrals. The new intramolecular hydrogen bond,
deshielded ones of the remaining deutered signals because they are
involved inmoderate intramolecularhydrogenbondswith thehydra-
zinic nitrogen atoms (see below). These interactions, which are
responsible for the formation of six-membered rings, must produce
an important deshielding of the hydrogen atoms of O(1)–H groups.
Differently, the hydrogen corresponding to O(1)–H group is the most
1
–3
N(2)–HÁ Á ÁO(1), in the HL
adducts is likely the reason of the
well-defined two signals for the hydroxyl groups. Nevertheless,
the methyl group in the acetophenone derivatives, HL4 , hin-
ders the formation of this hydrogen bond. Finally, the resor-
cinol group occupies two possible orientations of the O(1)–H
group with respect to the non-symmetric rhenium center.
–6
4
–6
deshielded signal in HL and the signal appears around 11.5 ppm.

A. Núñez-Montenegro et al. / Polyhedron 65 (2013) 221–228
225
Table 3
Selected bonds lenghts (Å) and angles (°) in 1bÁH
2
O, 3b, 4aÁ(CH
3
)
2 3
CO.(CH CH
2
)
2 3 2 2
O and 5bÁ(CH CH ) O.
1
2
b.H O
3b
4a (CH
3 2
) CO.(CH
3
CH
2 2
) O
3 2 2
5b.(CH CH ) O
Re(1)–N(3)
Re(1)–S(1)
Re(1)–Br(1)/Cl(1)
S(1)–C(1)
N(1)–C(1)
C(1)–N(2)
N(2)–N(3)
C(2)–N(3)
C(2)–C(3)
2.196(5)
2.4652(17)
2.6518(9)
1.694(6)
1.324(8)
1.338(8)
1.392(7)
1.295(8)
1.447(8)
–
2.183(9)
2.449(3)
2.6703(15)
1.644(15)
1.363(14)
1.401(16)
1.384(12)
1.292(13)
1.476(15)
–
2.242(4)
2.239(6)
2.452(2)
2.4565(17)
2.5273(16)
1.682(6)
1.308(6)
1.350(6)
1.407(6)
1.307(6)
1.482(7)
–
2.6529(10)
1.698(8)
1.313(9)
1.347(9)
1.385(7)
1.292(8)
1.479(10)
1.447(9)
1.358(9)
1.368(9)
N(1)–C(9)
O(1)–C(4)
O(2)–C(6)
1.364(7)
1.364(7)
1.404(14)
1.690(14)
1.370(7)
1.354(7)
N(3)–Re(1)–S(1)
N(3)–Re(1)–Br(1)/Cl(1)
S(1)–Re(1)–Br(1)/Cl(1)
C(1)–S(1)–Re(1)
N(1)–C(1)–N(2)
N(1)–C(1)–S(1)
79.20(13)
87.46(14)
88.12(5)
98.9(2)
117.7(6)
119.7(5)
122.5(5)
121.0(5)
137.5(6)
117.8(5)
124.5(4)
117.5(4)
–
80.0(2)
83.09(2)
86.01(9)
99.6(5)
115.8(12)
121.0(12)
123.2(9)
119.3(9)
131.5(11)
114.9(9)
127.3(8)
117.8 (6)
–
79.46(13)
83.93(12)
85.69(6)
99.6(2)
116.3(5)
121.3(5)
122.4(5)
122.1(5)
118.1(5)
114.9(5)
130.6(4)
114.4(3)
–
78.44(16)
82.41(15)
86.75(5)
99.5(3)
117.2(7)
122.8(6)
120.0(6)
123.1(6)
118.0(7)
115.9(6)
129.7(5)
113.4(4)
123.2(7)
123.0(7)
119.0(6)
N(2)–C(1)–S(1)
C(1)–N(2)–N(3)
N(3)–C(2)–C(3)
C(2)–N(3)–N(2)
C(2)–N(3)–Re(1)
N(2)–N(3)–Re(1)
C(1)–N(1)–C(9)
N(3)–C(2)–C(12)
C(3)–C(2)–C(12)
–
–
–
–
123.9(5)
117.9(5)
These aspects are more soundly discussed in the X-ray section
3.2. X-ray studies
(
vide infra).
On the other hand, the X-ray study of materials obtained from
3.2.1. Crystal and molecular structure of adducts 1bÁH
CH CH
The molecular structures and the numbering schemes of these
compounds are included in Fig. 1. Selected bond lengths and angles
are listed in Table 3.
2
O, 3b,
the mother liquors of 5a, 5b and 6b, or from DMSO solutions of
c showed the spontaneous formation of binuclear thiosemicar-
bazonate complexes. In a process similar to that observed before
4], deprotonation of the TSC ligand and labilization of the halogen
4aÁ(CH
3
)
2
COÁ(CH
3
2 2
)
O and 5bÁ(CH
3
2 2
) O
6
[
with the resulting vacant position induces its occupation by the
sulfur atom of an adjacent TSC complex molecule. We have ob-
served in other TSC complexes that the process can be accelerated
by addition of strong bases such as NaOH or NaOMe. Nevertheless,
the isolation of these thiosemicarbazonate compounds in the res-
orcinol derivatives was more difficult because of the simultaneous
Single crystals of 1b, 3b, 4a and 5b adducts were grown from
the mother liquor, and most of them contain solvent molecules
trapped in the crystal lattice.
As we have observed for other rhenium(I) TSC compounds, the
ligand is coordinated to rhenium(I) through the sulfur S(1) and
azomethine nitrogen N(3). This coordination mode changes the
configuration of the bond C(1)–N(2) from E, observed in the
structure of the ligands [4,8] to Z to form a five membered chelate
ring. This ring is not planar, for example in 4a the rhenium atom
is 0.408(4) Å above the mean least-square plane formed by the
S(1)/C(1)/N(2)/N(3) atoms. Re–S(1)and Re–N(3) distances are
similar to the corresponding values observed previously in others
adducts of TSC [4]. The coordination sphere around the rhenium
atom is completed with the three carbonyl carbon atoms in
precipitation of the mononuclear halide complexes. In fact, we only
6
could obtain pure material of [Re
2
(L )
2
(CO)
6
] (6c) (Scheme 2)
although we have also observed the formation of such compounds
by diffractometric studies on single crystals obtained from solu-
1
tions of 5a. The H NMR spectra show all the proton signals shifted
to lower field with respect to the free ligands. They are also in
agreement with the deprotonation of the ligands by the absence
of the signals of the N(2)–H protons.
OH
OC
OC
CO
Re Br
S
NHPh
OC
OC
CO
S
N
N
OH
+
Na(OCH3)
NaBr
Re
S
HO
HO
N
HN
-
HO
HO
N
Re
CO
CO
NHPh
N
OC
PhNH
Scheme 2. Synthesis of the thiosemicarbazonate complex 6c.

2
26
A. Núñez-Montenegro et al. / Polyhedron 65 (2013) 221–228
Fig. 1. Molecular structures with numbering schemes of 1b (A), 3b (B), 4a (C), and 5b (D).
fac arrangement and the halogen atom. The coordination polyhe-
dron may be described as a distorted octahedron. The main dis-
tortion is the angle S(1)–Re–N(3) due to the formation of the
chelate ring.
The bond distances and angles are very similar in the four ad-
ducts and only statistical differences are detected in the Re–S
and Re–X bonds and in the ligand frameworks. Nevertheless, there
are differences in the Re–N(3) bond distances and N(3)–C(2)–C(3)
angles depending on the kind of ligand. The Re–N(3) distances
are shorter in the dhb derivatives 1b and 3b than in the dha deriv-
atives 4a and 5b. A contrary trend is observed in the values of the
N(3)–C(2)–C(3) angles, being around 130° in 1b and 3b, but are
noticeably larger in 4a and 5b. Actually, the configuration of the
Respect to the molecular association of 1bÁH
2
O, two interac-
tions between the O(2)–H and O(103) groups allow the formation
of chains (graph C(12)). These chains are associated by N(1)–
HÁ Á ÁO(2) hydrogen bonds (graph C(16)) forming slides (Figure S2).
The water molecule is included in these slides by acceptor interac-
tions with the O(1)–H group. These results show that O(1)–H,
N(1)–H and N(2)–H together with the O(2)–H group are active
hydrogen bond donor groups. They establish several interactions
with acceptor groups of adjacent complex and solvent molecules
(Table S1).
In 3b, the adduct molecules are linked together forming
dimers through hydrogen bonds between the N(1)–H group and
2
Br(1) atom (graph descriptor R
2
(12); Table S1), and these
C(2)@N(3) bonds is also different in both groups of compounds
dimers are also associated in parallel chains involving the atoms
O(1) and O(2) and, Br(1) (graph C(8)). Moreover, we observed a
series of weak interactions also in the molecular packing
(Figure S3).
It is interesting that the molecules of the adduct 4a are con-
nected with two solvent molecules, one of acetone and the other
of ether. The interactions are strong enough to be kept inside the
crystal network, even at room temperature. The structural param-
eters observed (Table S1) confirm the strength of these interac-
tions. On the other hand, the molecules of the adduct are
+
(
3
without regard to the fragment {Re(CO) } }): it is Z in 1a and 3b
but E in compounds 4a and 5b. The reason of the different behavior
is doubtlessly the methyl group at the C(2) atom in the acetophe-
none derivatives, which imposes steric hindrances when the ligand
is coordinated. Thus, in the dhb derivatives the resorcinol groups
are involved in hydrogen bonds (graph descriptor S(6), see Ref.
[
15]) with the O(1)–H groups as acceptors against the N(2)–H
groups (Fig. 1A and B). Although in the solid state structures of
the free ligands [6] the O(1)–H groups are the donor groups and
the N(3) the acceptor groups, the metric values of the hydrogen
bonds, remarkably the O(1)–N(3/2) distances, are very similar. This
interaction is impossible in the acetophenone derivatives because
in the E configuration of the C(2)@N(3) bond the methyl group
points to the N(2)–H. The resorcinol groups in the dha derivatives
must take non planar conformations because of the steric strain
due to the metal carbonyl fragments as is depicted in Fig. 1C and D.
The steric hindrance in the acetophenone derivatives is likely
responsible for the sensible lengthening of the Re(1)–N(3) bonds
and the wider angles C(2)–N(3)–Re(1) (see Table 3). The remaining
bond distances and angles are statistically equivalent in all adduct
structures.
associated in dimers by hydrogen bonds involving the N(2)–H
1
and N(1)–H groups, and chloride (R
2
(6)) and the oxygen atom
2
2
O(1) (R (36)) from a adjacent molecule. These centrosymmetric
dimers are associated in parallel chains (Figure S4) by interactions
between N(1)–H group and the oxygen atom O(103) of a carbonyl
group (graph C(7)).
In 5bÁ(CH
3 2 2
CH ) O, molecules are associated in dimers by
hydrogen bonds which involve the N(1)–H, N(2)–H groups and
1
2
the Br(1) atom (R (6)). These dimers are also associated in par-
allel chains (graph C(11)) by interactions between O(2) and S(1)
atoms (Figure S5, Table S1). The presence of an ether molecule,
which is involved in a hydrogen bond with the donor atom

A. Núñez-Montenegro et al. / Polyhedron 65 (2013) 221–228
227
molecules (vide infra). Crystals of 5d were obtained from acetone
solutions of 5b, as a result of the substitution of the 2,4-dihydroxy-
acetophenone group by an acetone molecule. We have included
this structure for comparative purposes.
As observed in other rhenium(I) thiosemicarbazonates, the
deprotonation of the organic ligand and the labilization of the hal-
ogen in adducts produces that the rhenium complexes dimerize by
linking of the sulfur atom of a neighboring molecule at the position
previously occupied by the halogen atom. This produces centro-
symmetric dimers in the complexes included in this work, but dis-
symmetric structures have also been observed before [4]. The Re–S
bond to the sulfur atom belonging to the chelating system of the
neighboring rhenium atom is about 0.1 Å larger than that of that
of its own chelate. In fact, the Re–S–Re bridge is relatively asym-
metric, as in other dimeric structures based on this type of interac-
2 2
tions. In the diamond Re S , the bond angles are close to 90° and
the distance Re–Re in these compounds is too long (>3.75 Å) for
any significant bonding interactions.
The molecular structures of the dimers included in this paper
display only slight differences in the bond distances and angles
and, more noticeably, with the corresponding adducts. Unfortu-
nately, we were unable to obtain single crystals of derivatives of
dhb and the effect of the methyl group on the C(2) atom cannot
be surely evaluated. Nevertheless, the bond distances and angles
involving the metal-ligand coordination are similar to those found
in other thiosemicarbazonate derivatives of aldehydes [4]. Any-
way, these findings, which have been observed previously, reflect
the structural flexibility of the thiosemicarbazone ligand in the for-
mation of the complexes.
The structure of the dimer 5c exhibits several hydrogen bonds.
Differently to the other resorcinol thiosemicarbazonates, an
intramolecular hydrogen bond (S(6)) is maintained, in this case
involving the hydroxyl group O(1)–H and the nitrogen atom
N(2) (Fig. 2A). This interaction is likely weaker than in the ad-
ducts as is reflected in the longer O(1)–N(2) distance. In addition,
each dimer is associated in chains by O(2)–HÁ Á ÁO(1) (graph C(7))
and N(1)–HÁ Á ÁO(2) (graph C(12)) interactions (Figure S6,
Table S2).
The substitution of the resorcinol group by acetone in 5d
(Fig. 2B) affords slight differences with the dimers in the diamond
Re , since the Re–S–Re bridge is almost symmetric (Table 4).
2 2
S
However, the parameters related with the metal–ligand interac-
tions are hardly affected. The supramolecular structure is based
2
on interactions (graph R
2
(14)) involving the N(1)–H group and
the O(102) atom from a carbonyl group (Figure S7, Table S2)
describing chains running parallel to ac crystallographic plane.
Other carbonyl groups (O(101) and O(102)) organize the final
structure in sheets.
Fig. 2. Molecular structures showing the numbering schemes in 5c (A), 5d (B), and
c (C) (solvents were removed for clarity).
6
The different nature of the solvents (diethylether and DMSO) in
the two crystal structures does not impose relevant differences in
the molecular structure of the complex 6c. In fact, there are no sub-
O(1), introduces only slightly modifications in the supramolecu-
lar packing.
stantial differences with the other dimers. In the 6cÁ2(CH
3 2 2
CH ) O,
the non-coordinated ether molecules are connected with the dimer
through intermolecular hydrogen bonds O(1)–HÁ Á ÁO(1E) and O(2)–
HÁ Á Á(O2E), and dimers are associated with each other by a hydro-
3
6
.2.2. Crystal and molecular structure of 5c, 5d, 6cÁ2(CH
3 2 2
CH ) O and
cÁ3DMSO
gen bond involving a thioamide group N(1)–H and the oxygen
2
The molecular structures including the numbering schemes
O(2) of a hydroxyl group (graph R
2
(24)) from a neighboring dimer
6
used are depicted in Fig. 2. Table 4 lists a selection of the bond dis-
tances and angles.
2 2 6
(Table S2). This interaction associates the [Re (L ) (CO) ] units in
chains running parallel to b crystallographic axis (Figure S8).
In 6cÁ3DMSO, the presence of three molecules of DMSO affects
the association of the centrosymmetric dimers. Each dimeric unit
establishes hydrogen bonds with three molecules of DMSO by
O(1)–HÁ Á ÁO(1)W and O(1)–HÁ Á ÁS(1)W, O(2)–HÁ Á ÁO(1)W and N(1)–
HÁ Á ÁO(2)W. The latter interaction is responsible for the dimers
association. These interactions form chains running along to a
and c crystallographic directions (Figure S9).
We have obtained single crystals of 5c and 6cÁ2(CH
3 2 2
CH ) O by
slow evaporation of the mother liquor of the adducts 5a and 6b.
The dimethylsulfoxide solvate of 6c, was also obtained by crystal-
lization from DMSO solutions. Both 6c structures are virtually
equivalents: the main differences are due to the different solvent
included in the crystal lattice, but are only statistical differences
in the bond lengths and angles are detected inside the complex

2
28
A. Núñez-Montenegro et al. / Polyhedron 65 (2013) 221–228
Table 4
Relevant interatomic distances (Å) and angles (°) for 5c, 5d, 6cÁ2(CH
3
CH
2
)
2
O and 6cÁ3DMSO.
c#1
5d#2
6cÁ2(CH
2.226(3)
3 2 2
CH )
O#3
6cÁ3DMSO
2.210(4)
#4
5
Re(1)–N(3)#3
Re(1)–S(1)
2.231(9)
2.487(3)
2.544(3)
2.228(4)
2.4756(11)
2.5341(12)
1.777(5)
1.463(7)
1.294(5)
1.414(5)
–
2.4588(12)
2.5451(13)
1.779(4)
1.363(5)
1.289(5)
1.419(5)
1.282(5)
1.500(6)
1.356(6)
1.379(5)
2.4737(13)
2.5317(13)
1.793(5)
1.364(6)
1.288(6)
1.425(5)
1.299(6)
1.492(7)
1.357(6)
1.360(7)
Re(1)–S(1)#
S(1)–C(1)
N(1)–C(1)
C(1)–N(2)
N(2)–N(3)
C(2)–N(3)
C(2)–C(21)
O(1)vC(4)
O(2)–C(6)
1,2,3,4
1.780(10)
1.323(13)
1.314(12)
1.424(12)
1.306(13)
1.506(14)
1.361(13)
1.367(13)
–
–
–
N(3)–Re(1)–S(1)#3
77.6(2)
83.6(2)
81.62(11)
98.38(11)
–
95.7(4)
131.3 (7)
115.8(6)
116.3(8)
112.8(9)
76.80(9)
83.02(10)
82.02(4)
97.98(4)
–
78.59(9)
88.05(10)
80.96(4)
99.04(4)
69.92(15)
100.36(15)
129.3(3)
119.0(2)
116.8(3)
110.9(3)
77.38(11)
83.57(11)
81.99(4)
98.01(4)
105.04(16)
95.05(17)
131.4(3)
117.1(3)
115.3(4)
111.5(4)
#1,2,3,4
N(3)–Re(1)–S(1)
S(1)–Re(1)–S(1)#
Re(1)–S(1)–Re(1)
C(1)–S(1)–Re(1)#
C(1)–S(1)–Re(1)
C(2)–N(3)–Re(1)
1,2,3,4
#1,2,3,4
3,4
–
#3
130.3(3)
116.8(2)
115.6(4)
112.9(4)
N(2)–N(3)–Re(1)#3
C(1)–N(2)–N(3)
C(2)–N(3)–N(2)
a
Symmetry transformations used to generate equivalent atoms: #1 = Àx + 1,Ày,Àz + 1; #2 = Àx,Ày,Àz + 2; #3 = Àx + 2,Ày + 1,Àz + 1; #4 = Àx + 1,Ày,Àz + 2.
4
. Conclusions
associated with this article can be found, in the online version, at
http://dx.doi.org/10.1016/j.poly.2013.08.038.
New rhenium(I) compounds with the general formula
n
[
ReX(CO)
3
(HL )] (X = Cl, Br; n = 1–6) have been isolated. Spectro-
References
scopic data and X-ray diffraction studies confirm the formation of
a five-membered chelate ring via coordination of the sulfur and
the azomethine nitrogen atoms (j-S,N(3)). A carefully study of
[
[
[
1] A. Mahmood, A.G. Jones, Handbook of Radiopharmaceuticals: Radiochemistry
and Applications, Wiley-VHC, 2002.
2] S.R. Banerjee, K.P. Maresca, L. Francesconi, J. Valliant, J.W. Babich, J. Zubieta,
Nucl. Med. Biol. 32 (2005) 1.
3] a) R. Alberto, R. Schibli, A. Egli, P.A. Schubiger, W.A. Hermann, G. Artus, U.
Abram, T.A. Kaden, J. Organomet. Chem. 493 (1995) 119;
b) R. Alberto, K. Ortner, N. Wheatley, R. Schibli, P.A. Schubiger, J. Am. Chem.
Soc. 123 (2001) 3135;
c) R. Waibel, H. Treichler, N.G. Schaefer, D.R. van Staveren, S. Mundwiler, S.
Kunze, M. Kuenzi, R. Alberto, J. Nuesch, A. Knuth, H. Moch, R. Schibli, P.A.
Schubiger, Cancer Res. 68 (2008) 2904.
the bond angles and distances shows only small variations of
the bonding parameters with respect to the nature of the halogen.
In the dha derivatives, the presence of a methyl group in C(2) po-
sition has effects on the intermolecular association and on the fi-
nal configuration of the ligand in the adduct. The presence of
solvents with hydrogen bonding acceptor is attributable to the
high activity of the OH and NH groups to establish this kind of
interactions.
[4] M. Khan, V. Enkelmann, G. Brunklaus, Cryst. Growth Des. 9 (2009) 2354.
[
[
[
5] T.L. Nguyen, A. Scott, B. Dinkelmeyer, F.W. Fowler, J.W. Lauher, New J. Chem.
22 (1998) 129.
6] a) M. Yıldız, H. Ünver, D. Erdener, A. Kiraz, N. Ocak, J. Mol. Struct. 919 (2009) 227;
b) K.W. Tan, C.H. Ng, M.J. Maah, S.W. Ng, Acta Crystallogr., Sect. E 64(2008) o2224.
7] a) A. Núñez-Montenegro, R. Carballo, E.M. Vázquez-López, Polyhedron 27
n
The deprotonation of HL (n = 6) and labilization of the halogen-
6
ido ligands induce the formation of the dimeric complex [Re
CO)
2
(L )
2
(
6
], where the coordination involves Re–S–Re bridges, where S
(
2008) 2867;
is the thiolate sulfur atom of a
onate ligand.
j-S,N(3)-bidentate thiosemicarbaz-
b) A. Núñez-Montenegro, R. Carballo, E.M. Vázquez-López, Polyhedron 28
(2009) 3915;
c) A. Núñez-Montenegro, R. Carballo, E.M. Vázquez-López, J.M. Hermida-
Ramón, Polyhedron 30 (2011) 2146;
d) R. Carballo, J.S. Casas, E. García-Martínez, G. Pereiras-Gabián, A. Sánchez, J.
Sordo, E.M. Vázquez-López, Inorg. Chem. 42 (2003) 6395.
8] a) I.G. Santos, U. Abram, R. Alberto, E.M. Vázquez-Lopez, Inorg. Chem. 43
Acknowledgements
[
[
(
2004) 1834;
This research was supported by the European Rural Develop-
ment Fund and Spanish Ministry of Education and Science through
project CTQ2010-19386/BQU.
b) R. Carballo, J.S. Casas, E. García-Martínez, G. Pereiras-Gabián, A. Sánchez, J.
Sordo, E.M. Vázquez-López, J.C. García-Monteagudo, U. Abram, J. Organomet.
Chem. 656 (2002) 1;
c) G. Pereiras-Gabián, E.M. Vázquez-López, H. Braband, U. Abram, Inorg. Chem.
44 (2005) 834.
9] D.D. Perrin, W.L.F. Armarego, Purification of Laboratory Chemicals, third ed.,
New York, Oxford, 1988.
Appendix A. Supplementary data
[
[
[
10] M.F. Farona, K.F. Kraus, Inorg. Chem. 9 (1970) 1700.
11] S.P. Schmidt, W.C. Trogler, F. Basolo, Inorg. Synth. 28 (1990) 160.
12] G.M. Sheldrick, Acta Crystallogr. Sect. A 64 (2008) 112.
A MULTIPURPOSE CRYSTALLOGRAPHIC TOOL, Utrecht University, The
Netherlands, 2010.
14] I.J. Bruno, J.C. Cole, P.R. Edgington, M.K. Kessler, C.F. Macrae, P. McCabe, J.
Pearson, R. Taylor, Acta Crystallogr., Sect. B 58 (2002) 389.
15] M.C. Etter, Acc. Chem. Res. 23 (1990) 120.
CCDC 940252–940259 contain the supplementary crystallo-
graphic data for 1bÁH
2
O, 3b, 4aÁ(CH
3
)
2
COÁ(CH
3
CH
2
)
2
O
5bÁ
[13] A.L. Spek, PLATON,
(
CH CH O, 5c, 5d, 6c. 2(CH
3
2
)
2
3
CH
2 2
)
O and 6cÁ3DMSO. These data
[
[
can be obtained free of charge via http://www.ccdc.cam.ac.uk/con-
ts/retrieving.html, or from the Cambridge Crystallographic Data
Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223
3
36 033; or e-mail: deposit@ccdc.cam.ac.uk. Supplementary data