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182
R. Csonka et al. / Polyhedron 34 (2012) 181–187
of a new lipophilic ligand type, which we term glyoxylato-aro-
ylhydrazones (gly-AH), the structural description of new gly-AH
complexes and the testing of the activity of these ligands in APX
and AO mimicking reactions.
158.0, 198.2. IR (ATR) (cmꢀ1): 3166, 3031, 2963, 2927, 2872,
1685, 1665, 1605, 1534, 1459, 1439, 1364, 1273, 1225, 1099,
1012, 972, 857, 825, 750. ESI-MS (DCM/MeOH): m/z (%) = 487.20
[M+Na+]. Molecular formula: C29H40N2O3. Molecular weight:
464.64 g/mol.
2. Materials and methods
2.3.2.2. (L2) (E)-N0-(2-hydroxy-3-(pentan-3-yl)benzylidene)-2-mesi-
tyl-2-oxoacetohydrazide. Mp.: 149–151 °C. 1H NMR (300 MHz,
DMSO) d (ppm): 12.78 (s, 1 H), 11.64 (s, 1 H), 8.69 (s, 1 H), 7.27
(d, J 8.0, 1 H), 7.23 (d, J 8.0, 1 H), 6.96 (m, 3 H), 3.00–2.86 (m, 1
H), 2.83 (s, 3 H), 2.17 (s, 6 H), 1.74–1.43 (m, 4 H), 0.72 (t, J 7.0, 6
H); 13C NMR (150 MHz, DMSO) d (ppm): 12.4, 19.6, 21.2, 27.7,
40.7, 117.4, 119.7, 129.0, 129.6, 130.7, 132.8, 135.8, 140.5, 154.5,
156.7, 158.7, 196.3. IR (ATR) (cmꢀ1): 3186, 3051, 2964, 2933,
2873, 1695, 1675, 1604, 1549, 1453, 1379, 1268, 1232, 1209,
1157, 1091, 975, 833, 754, 702. ESI-MS (DCM/MeOH): m/z
(%) = 403.10 [M+Na+]. Molecular formula: C23H28N2O3. Molecular
weight: 380.48 g/mol.
2.1. Materials
The solvents and chemicals used for synthesis were purchased
from Sigma–Aldrich and Alpha Aesar. DFO (desferrioxamine) was
purchased from Novartis Pharma AG, Basel, Switzerland. They
were used without further purification. Spectrograde solvents
were used for the recording of UV–Vis spectra.
2.2. Analytical measurements
Infrared spectra were recorded on a Bruker Tensor 27 spectro-
photometer using an ATR (attenuated total reflectance) assembly.
UV–Vis spectra were recorded on a Cary 100 Conc spectrophotom-
eter using quartz cells. ESI-MS spectra were recorded by a Thermo
LCQ Fleet instrument. NMR spectra were recorded using Varian
300 and 600 MHz instruments.
2.3.2.3. (L3) (E)-2-(4-(dimethylamino)phenyl)-N0-(2-hydroxy-3-(pen-
tan-3-yl)benzylidene)-2-oxoacetohydrazide. Mp.: 231–232 °C. 1H
NMR (600 MHz, DMSO) d (ppm): 12.54 (s, 1 H), 11.78 (s, 1 H),
8.53 (s, 1 H), 7.96 (d, J 9.0, 2 H), 7.25 (d, J 7.0, 1 H), 7.22 (d, J 7.0,
1 H), 6.93 (t, J 7.0, 1 H), 6.80 (d, J 9.0, 2 H), 3.10 (s, 6 H), 3.00–
2.92 (m, 1 H), 1.74–1.51 (m, 4 H), 0.75 (t, J 7.0, 6 H); 13C NMR
(75 MHz, DMSO) d (ppm): 12.4, 27.8, 40.1, 111.4, 117.5, 119.6,
120.2, 129.5, 130.5, 132.7, 152.8, 154.8, 156.7, 161.7, 185.9. IR
(ATR) (cmꢀ1): 3277, 3240, 2962, 2931, 2870, 1693, 1664, 1574,
1505, 1440, 1382, 1305, 1167, 947, 836, 751, 621. ESI-MS (MeOH):
m/z (%) = 404.10 [M+Na+]. Molecular formula: C22H27N3O3. Molec-
ular weight: 381.47 g/mol.
2.3. Synthesis of glyoxylato-aroylhydrazones
2.3.1. Two procedures were used for the preparation of hydrazides
Method A (via acid chloride): Substituted arylglyoxylic acid
(5 mmol) was dissolved in 10 ml SOCl2 and the solution was
heated at reflux temperature overnight. Excess SOCl2 was removed
by rotary evaporation and the crude product was dried under vac-
uum to yield substituted arylglyoxylic acid chlorides (95–98% light
yellow oils) without further purification. A solution of the acid
chloride (5 mmol) in CH2Cl2 (15 ml) was added dropwise over
40 min to a solution of hydrazine-hydrate (3 ml, 30 w/v% hydra-
zine-hydrate in 15 ml EtOH) cooled in an ice bath. Upon addition,
the mixture was stirred at room temperature for 1 h. The crude
precipitate was filtered and washed with saturated NaHCO3, hex-
ane and then finally dried under vacuum. Yield: 60–70% white
powder.
Method B (via ester): The methyl ester of the corresponding aryl-
gyloxylic acid can be prepared very rapidly using diazomethane
[9]. The ester (0.4 g (approx. 2 mmol)) is converted to the hydra-
zide using an excess of 30 w/v% hydrazine-hydrate (1 ml dissolved
in 15 ml EtOH or MeOH) with sonication for 20 min at 40 kHz in an
ultrasonic bath. The precipitate formed was filtered, washed with
EtOH and dried under vacuum. Yield: 75–95% white powder.
2.4. Synthesis of transition metal complexes of glyoxylato-
aroylhydrazones
Cu(OAc)2ꢁ2H2O or Zn(OAc)2ꢁ2H2O (2 mmol) was added to a
solution of gly-AH ligands (2 mmol) in a methanol–pyridine (1:1)
mixture (5 ml). After stirring for 5 min the solution was then left
Table 1
Summary of the crystallographic data and structure parameters for C1 and C2.
Compound
C1
C2
Chemical formula
Formula weight
Crystal system
Space group
Unit cell dimensions
a (Å)
C
33H36CuN4O3
C33H36N4O3Zn
602.03
600.20
triclinic
P1
triclinic
ꢀ
ꢀ
P1
8.5089(1)
14.1869(2)
14.4149(3)
110.281(1)
102.053(1)
104.001(1)
1499.60(4)
2
8.3443(1)
14.1889(2)
14.3665(3)
108.935(1)
100.465 (1)
104.421(1)
1492.89(4)
2
b (Å)
c (Å)
2.3.2. The preparation of glyoxylato-aroylhydrazones (L1–L3)
A solution of the corresponding hydrazide (1 mmol) and 3-(1-
ethylpropyl)-2-hydroxybenzenecarbaldehyde (1.05 mmol) [10] in
methanol was heated at reflux temperature overnight. The solvent
was then removed by rotary evaporation and the remaining pow-
der was washed with hexane, filtered and dried under vacuum to
yield the corresponding glyoxylato-aroylhydrazones as light yel-
low powders (45–87%).
a
(°)
b (°)
c
(°)
Volume (Å3)
Z
Calculated density
1.329
1.339
(g cmꢀ1
)
Temperature (K)
183(2)
1.342
160(2)
1.458
Absorption coefficient
(mmꢀ1
)
2.3.2.1. (L1) (E)-N0-(2-hydroxy-3-(pentan-3-yl)benzylidene)-2-oxo-2-
(2,4,6-triisopropylphenyl)-acetohydrazide. Mp.: 171 °C. 1H NMR
(300 MHz, DMSO) d (ppm): 12.81 (s, 1 H), 11.63 (s, 1 H), 8.73 (s,
1 H), 7.25 (m, 2 H), 7.12 (s, 2 H), 6.94 (t, J 7.0, 1 H), 3.00–2.85
(m, 2 H), 2.66–2.55 (m, 2 H), 1.71–1.49 (m, 4 H), 1.23 (d, J 7.0, 6
H), 1.16 (d, J 7.0, 12 H), 0.72 (t, J 7.0, 6 H); 13C NMR (75 MHz,
DMSO) d (ppm): 12.4, 24.2, 24.2, 27.7, 31.4, 34.2, 40.7, 117.4,
119.8, 121.2, 129.7, 130.7, 132.8, 145.8, 151.0, 154.7, 156.7,
F (000)
630
632
Observed reflections
Goodness-of-fit (GOF) on
F2
4548
1.028
4465
1.050
Final R indices [I > 2(I)]a
R1 = 0.0471,
R1 = 0.0312,
wR2 = 0.1253
wR2 = 0.0805
P
2
w ¼ 1=½r2ðF20Þ þ ð
a
PÞ þ bPꢂ and P ¼ ððmax F20; 0Þ þ 2Fc2Þ=3.R1
¼
ðjF0j ꢀ jFcjÞ=
a
P
P
P
2
2
1=2
ðjF0jÞ and wR2 ¼ f ½wðF20 ꢀ Fc2Þ ꢂ= ½wðF02Þ ꢂg
.