4
A. BARTꢀꢁꢂL AND H. GꢃUCHOꢄSꢅA
Preparation of 2,2′-[1,3-propanediyl)bis(nitriloeth-1-yl-1-ylidene)]diphenol (H L)
2
The Schiff base (scheme 1) was synthesized in a similar way to methods described previously [5, 6, 8].
Mixtures of 10 mmol (1.361 g) of 2′-hydroxyacetophenone and 5 mmol (0.372 g) of 1,3-propanediamine
in 35 ml of methanol were refluxed for 2 h. Then excess solvent (approx. 25 ml) was evaporated and
the mixture was cooled to 4 °C. The yellow precipitate was collected by filtration, washed with cold
methanol, and dried in air.
H L (where L = C H N O ): yellow powder; yield: (92.1%, 1.429 g); ꢂlem. Anal. for C H N O (Fꢄ
2
19 20
2
2
19 22
2
2
−1
−1
3
3
1
10.32 g mol ) (%): Calcd C 73.52, H 7.14, N 9.03; found C 73.68, H 7.07, N 8.99. FTIR bands (ν/cm ):
061 (vw), 3019 (vw), 2945 (vw), 2922 (w), 2846 (vw), 1612 (s), 1568 (s), 1495 (s), 1447 (s), 1426 (m),
375 (m), 1329 (m), 1307 (s), 1266 (s), 1232(s), 1160 (m), 1153 (m), 1130 (m), 1082 (m), 1058 (m), 1025
(
m), 981 (s), 940 (m), 933 (m), 912 (m), 878 (m), 859 (m), 830 (s), 755 (vs), 746 (vs), 636 (s). 1H NMR (δ,
DMSO-d ): 2.04–2.13 (quint, 2H,>CH ), 2.38 (s, 6H, 2xCH ), 3.69–3.73 (t, 4H, 2x>CH ), 6.73–6.80 (m, 4H,
6
2
3
2
ArH), 7.25–7.31 (ddd, 2H, ArH), 7.63–7.67 (dd, 2H, ArH), 16.51 (s, 2H, 2xOH).
Synthesis of 1 and 2
The synthesis of the complexes was performed in methanol solution with a ratio of metal acetate to
the Schiff base of 1:1. To a hot solution of H L (0.64 mmol, 0.200 g) in MeOH (25 ml), copper(II) acetate
2
(
0.64 mmol, 0.129 g) dissolved in methanol (15 ml) was added. The mixture was refluxed for 1 h and
then about 20 ml of methanol was evaporated. The dark brown solution was split into two parts and
allowed to evaporate; one was left at room temperature (20 °C) and the second portion was left in the
refrigerator at 4 °C. After a few days, black crystals started to form in both reaction mixtures. The crystals
of 1 and 2 after grinding were dark green.
CuL·MeOH (1), 2,2′-((propane-1,3-diyl)bis(nitriloeth-1-yl-1-ylidene))diphenolato-copper(II) methanol
−
1
solvate,: black block; yield: (69.3%, 0.090 g); ꢂlem. Anal. for C H CuN O (Fꢄ 403.95 g mol ) (%): Calcd
1
9
22
2
3
−1
C 50.46, H 5.09, N 6.93; found C 50.31, H 4.99, N 6.84. FTIR bands (ν/cm ): 3368 (w), 3066 (vw), 3015
(
(
(
vw), 2945 (vw), 2919 (w), 2893 (w), 2813 (w), 1595 (vs), 1579 (vs), 1537 (vs), 1467 (w), 1439 (vs), 1362
m), 1317 (vs), 1287 (w), 1257 (s), 1244 (s), 1191 (w), 1160 (m), 1137 (s), 1082 (w), 1060 (w), 1043 (s), 998
m), 940 (m), 930 (m), 860 (w), 849 (s), 835 (m), 746 (vs), 668 (w).
[
{CuL} {Cu L }]·2MeOH (2), bis(μ-2,2′-((propane-1,3-diyl)bis(nitriloeth-1-yl-1-ylidene)diphenola-
2 2 2
to)-di-copper(II) bis((2,2′-((propane-1,3-diyl)bis(nitriloeth-1-yl-1-ylidene))diphenolato)-copper(II)) meth-
anol solvate: black block; yield: (39.2%, 0.049 g); ꢂlem. Anal. for C H Cu N O (Fꢄ 1551.76 g mol )
%): Calcd C 60.37, H 5.72, N 7.22; found C 60.21, H 5.89, N 7.35. FTIR bands (ν/cm ): 3320 (w), 3081 (vw),
−1
7
8
88
4
8
10
−
1
(
3
1
1
016 (vw), 2929 (w), 2915 (w), 2894 (w), 2808 (vw), 1593 (vs), 1582 (vs), 1530 (s), 1465 (m), 1433 (vs),
374 (m), 1354 (m), 1332 (vs), 1312 (vs), 1267 (s), 1258 (s), 1236 (s), 1210 (s), 1195 (m), 1163 (s), 1138 (s),
090 (w), 1063 (w), 1042 (s), 1005 (m), 933 (m), 884 (vw), 867 (w), 848 (s), 772 (s), 758 (s), 742 (vs), 721
(
s), 665 (w), 627 (w).
Methods and physical measurements
A Perkin-ꢂlmer CHN 2400 analyzer was used to determine carbon, hydrogen, and nitrogen contents in
1
the complexes. The H NMR spectrum of H L was recorded in DMSO-d solution using a Bruker Avance
2
6
spectrometer (0–17.50 δ ppm). Infrared spectra were obtained on a Nicolet 6700 FTIR spectrometer
using the ATR accessory on a diamond crystal for the pressed powder samples. The data were collected
between 4000 cm− and 650 cm , with a resolution of 4 cm for 16 scans. The UV–Vis spectra of H L, 1
1
−1
−1
2
−5
−5
and 2 were recorded in different solvents for solutions of the compounds at 2.5·10 or 1.3·10 M. The
studies were performed in 10 × 10 mm quartz cells from 200 to 900 nm using a GꢂNꢂSꢀS 10S UV–Vis
spectrophotometer. The electronic absorption spectra in protic and aprotic solvents are summarized
in table 2. Thermal stability and the decomposition of the analyzed complexes were determined with a
Setaram Setsys 16/18 derivatograph, recordingTG, DTG, and DSC curves. The samples (6.40 and 8.24 mg)