Facile preparation and characterization of some novel Schiff base complexes of uranyl(II), nickel(II), and zinc(II) ions

Article abstract of DOI:10.1080/24701556.2017.1357587

In this research, synthesis and characterization of some new Schiff base ligands derived from the reaction of 2,5-dihydroxybenzaldehyde with various aliphatic and aromatic diamines and their complexes using UO₂(II), Ni(II), and Zn(II) metal ion

Full text of DOI:10.1080/24701556.2017.1357587

Inorganic and Nano-Metal Chemistry
ISSN: 2470-1556 (Print) 2470-1564 (Online) Journal homepage: http://www.tandfonline.com/loi/lsrt21
Facile preparation and characterization of some
novel Schiff base complexes of uranyl(II), nickel(II)
and zinc(II) ions
Hossein Naeimi & Azam Karshenas
To cite this article: Hossein Naeimi & Azam Karshenas (2017): Facile preparation and
characterization of some novel Schiff base complexes of uranyl(II), nickel(II) and zinc(II) ions,
Inorganic and Nano-Metal Chemistry, DOI: 10.1080/24701556.2017.1357587
To link to this article: http://dx.doi.org/10.1080/24701556.2017.1357587
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Date: 01 August 2017, At: 02:49

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Facile preparation and characterization of some novel Schiff base complexes of uranyl(II),
nickel(II) and zinc(II) ions
Hossein Naeimi*, Azam Karshenas
Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, 87317,
I.R. Iran;
*Fax No.: +983615912397; Email: naeimi@kashanu.ac.ir
Abstract
In this research, synthesis and characterization of some new Schiff base ligands derived from
the reaction of 2,5-dihydroxybenzaldehyde with various aliphatic and aromatic diamines and
their complexes using UO2 (II), Ni(II) and Zn(II) metal ions are reported. The ligands are
found to be bound to the metal atom through the oxygen atoms of the hydroxyl groups and
nitrogen atoms of imine groups. Fourier transform infrared, UV-Vis, magnetic
susceptibilities, 1H NMR, 13C NMR and mass spectra were used to investigate the structures
of prepared materials. In these efficient protocols, Schiff base complexes were obtained in
high yields and appropriate reaction times.
Keywords
Schiff base, 2,5-Dihydroxybenzaldehyde, Complex, Transition metal, Diamines
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INTRODUCTION
Schiff bases are important class of compounds in medicinal and pharmaceutical field. They show
biological applications including antibacterial [1-6], antifungal [3-6] and antitumor activity [7,8].
Diamino tetradentate Schiff bases and their complexes have been used as biological models to
understand the structures of biomolecules and biological processes [9,10]. According to early
literature, T. Mangamamba in 2014 investigated physiological activity of synthesized complexes
with metal ions Cu(II), Ni(II), Co(II), Fe(III), Mn(II), Cr(III), and VO(II) with six ligands formed
by condensation products using azides and aldehydes or ketones are investigated [11].
Transition metal compounds containing Schiff base ligands have also been of great
interest for many years [12]. These compounds play an important role in the coordination
chemistry related to catalysis and enzymatic reactions, magnetism and molecular architectures
[13]. Effects of transition metal ions acting as Lewis acid catalysts on organic reactions have
been extensively investigated [14]. Although imines are labile and readily hydrolyzed, metal ions
stabilize imine bonds present on macrocyclic rings. Organometallic complexes containing Schiff
bases [15] have been used as catalysts for asymmetric cyclopropanation [16-19] and
enantioselective aziridination [20].
Salicylaldimine-type Schiff base ligands such as salen and their complexes derived from
the reaction of salicylaldehyde derivatives with diamines have been extensively studied in great
details for their various crystallographic, structural, and magnetic features [21-24].
Salen-type ligands having two hydroxy groups at the 5 and 5’ positions may have two
tautomeric forms, namely phenol-imine and keto-enamine forms, that keto-enamine form can be
used in analytical works [25-29].
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The hydroxy group is an electron-donating group and, due to its steric effects, has played
an important role in affecting the reactivity and enantioselectivities in synthesis as catalysts.
However, changes in the electronic, steric, and geometric properties of the ligand alter the orbital
at the metal center and thus affect its properties.
In continuation of ongoing to our research on the preparation of Schiff base ligands [30]
and their complexes [31-37], we decided to prepare some new Schiff bases and their complexes
of metal (II) including electron donor substituent under mild conditions in methanol solution.
The longer diamine bridge gave the higher electron density on the nitrogen atom, resulting in an
increase of molar absorptivity of the nπ* transition band due to the substituent effect on the
azomethine nitrogen [38], and increases the yield of Schiff base formation.
RESULTS AND DISCUSSION
Some Schiff bases named, 2,2'-[1,n--alkanediyl bis (nitrilomethylidene)]-bis(4-hydroxy-
phenol), have been prepared from 2,5-dihydroxybenzaldehyde and various aliphatic and aromatic
diamines under mild reaction conditions in methanol media (Scheme 1). When 2 mols of 2,5-
dihydroxybenzaldehyde and 1 mol aliphatic and aromatic diamine were reacted together, Schiff
bases 3a--h were obtained under mild conditions. The identity of these products was
demonstrated by spectroscopic and physical data. The results of these reactions are shown in
Table 1. As can be seen in this Table, with increasing the chain length of diamine, the time of the
reaction was increased and the product yield reduced. This can be due to increase the flexibility
of diamine that led to reduce closing the reactants in the reaction and also obtaining the product
with lower stability.
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In this research, we have synthesized Schiff base complexes by treatment of the Schiff
bases with Ni(II), and UO2(II) at room temperature as represented in Schemes 2 and 3. The
ligand (1 mol) was reacted with 1 mol respective metal (II) acetate, giving products summarized
in Tables 2 and 3. Schiff base complexes of metal (II) were afforded in excellent yields and
convenient reaction times.
We also synthesized Schiff base complexes by treatment of the Schiff base with Zn(II) at
40°C as represented in Scheme 4. The ligand (1 mol) was reacted with 1 mol zinc(II) acetate,
giving products summarized in Table 4. Schiff base complexes of zinc(II) were afforded in high
yields and convenient reaction time. Most of the complexes are colored, stable in air, soluble in
DMSO, DMF, MeOH and EtOH, but poorly soluble in diethyl ether.
Due to the electron donating of the hydroxy substitution at 5-position of phenyl ring, the
phenolic OH at 2-position becomes less acidic; and led to the increase of electron density on the
oxygen atom of hydroxyl group. Thus, the later affected on the synthetic conditions of the
complexes including the more strong coordination of ligand with metal ion. Basically, the
complex formation occurs in high yield and low reaction time at room temperature.
Electronic spectra
The structures of resulting Schiff bases and their complexes have been assigned by
physical and spectroscopic data. The electronic spectra of the ligands and their metal complexes
were recorded in methanol. The ligands show two bands at 320-370 nm and 250-260 nm, which
may be assigned to the nπ* and ππ* transition, respectively; the observed band at longer
wavelength can be assigned to keto tautomeric form of the Schiff base. The complexes show two
bands in the 200-260 and 290-360 nm ranges which are assigned to intra-ligand transition [39].
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In the complexes, the nπ* transitions due to the azomethine group are shifted to the lower
energy. From these results, the nitrogen atom of the imines group appears to be coordinated to
the metal ion. The ππ* band has been assigned to a transition involving mainly π molecular
orbitals of the aromatic ring of the salicylidenenimine moiety [40]. The spectra of the nickel (II)
Schiff base complexes exhibit a dd band in the visible region whose maximum of absorption
lies in the wavelength range 555--595 nm (4a, 4d and 4g).
IR spectra
The infrared spectra of the Schiff bases exhibit a band at 1618--1647 cm1 assignable to υ
C = N of azomethine. This band shifts lower by 10--15 cm1 on the chelation of ligand with
metal ion. The IR spectra of the complexes in comparison with the free ligands to determine the
changes that might have taken place during the complexation. The band at 1618-1647 cm1 is
characteristic of the azomethine nitrogen atom in the free ligand. The observed lowering in this
frequency to region 1602-1638 cm1 in all the complexes and indicates the involvement of the
azomethine nitrogen atom in coordination with metalation [41, 42]. Thus, the entire ligands act
as tetradentate chelating compound coordinated to metal ion through two oxygen and two
nitrogen atoms [43]. These data are well in accordance with those of reported complexes [44].
On the other hand, in all the synthesized complexes, the bands at 618--463 cm−1 and 463--420
cm−1 rang can be attributed to ν (M-N) and ν(M-O) bond, respectively.
1H NMR and 13C NMR spectra
In the 1H NMR spectra of the free ligands, the broad signal around δ = 12.13--12.80 ppm
is assigned to intramolecular hydrogen bonding on the ortho situation to the imine group, and the
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signal around δ = 8.91--9.10 ppm is assigned to hydroxyl groups on the meta situation to the
imine group, and a singlet band around δ = 8.4--8.9 ppm is attributed to azomethine hydrogen (-
CH = N), and signals around δ = 6.67--7.49 ppm are attributed to protons of aromatic rings (CH
1
= CH). In the H NMR spectra of the Schiff base complexes, all of these signals shift to lower
field and the broad signal around δ = 12.13--12.80 ppm disappears, proving complex formation
of ligand with metal ion. In 13C NMR spectra, the signal about δ = 167.08 ppm is assigned to the
carbon of imine (C = N), the aromatic carbons are between δ = 116--154 ppm and aliphatic
carbons are between δ = 25--59 ppm. The results are shown in Figs. 2 and 3 for 2,2'-[1,2--
phenilenediyl-bis(nitrilomethylidene)]-bis(4-
hydroxyphenol
and
2,2-(1,2-
Phenylenedilbisnitrilomethylidine)-bis(4-hydroxyphenolato) uranyl (II).
Intermolecular hydrogen bonding also accounts for the high frequency of the signals for
1
orthophenolic hydrogens in all the Schiff bases. By comparing the H NMR spectra of all the
Schiff bases with those of their corresponding metal(II) complexes, it is noted that there is a
downfield shift in the frequency of azomethine protons of the aromatic bridge and up to field
shift in the aliphatic bridge confirming coordination of the metal ion to both groups.
Mass spectra
In mass spectra of ligands, the signals related to the molecular ion confirmed the
structures of the products. In the spectra of the metal complexes, molecular ions corresponding to
the mononuclear structures were observed. Mass spectra are the only data that support monomers
for the complexes, and based on these data, a dimeric structure is unlikely.
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Magnetic properties
The magnetic susceptibility of a material, commonly symbolized by χm, is equal to the
ratio of the magnetization M within the material to the applied magnetic field strength H, or χm =
M/H. The magnitude of the paramagnetism is expressed as an effective magnetic moment, a
simple function of the number of unpaired electrons. Magnetism of transition metal complexes is
strongly influenced by coordination geometry and electron configuration [45]. In the presence of
large organic ligands, simple paramagnetism will be found only if there is sufficient magnetic
dilution. Results of magnetic susceptibility measurements of the some complexes are presented
in Table 5. The amounts of magnetic susceptibility for Ni(II) complexes typically range from 2.9
to 3.4 emu/gr.Oe for octahedral complexes and 3.2--4.1 emu/gr.Oe for tetrahedral complexes
[46] and for UO2(II) complexes typically range from 1.9 to 2.1 emu/gr.Oe [47]. The obtained
amounts for the Ni(II) complexes in this study range from 3.3 to 3.6 emu/gr.Oe and consistent
with the expected range for tetrahedral complexes.
CONCLUSION
In this research, we have reported a mild and convenient synthesis of Schiff base
complexes of Ni(II), Zn(II) and UO2(II). Prepared complexes can be used in various fields such
as; catalysts for epoxidation reaction, ring opening of epoxides, polymerization, for preparation
of ion selective electrode and etc. The Schiff bases for preparation of these complexes have been
obtained through simple and efficient reaction of 2,5-dihydroxybenzaldehyde with aliphatic and
aromatic diamines. The products are prepared in excellent yields and convenient reaction times.
The ligands are found to be bound to the metal atom through the oxygen atoms of the hydroxyl
groups and nitrogen atoms of imine chromophore which is also supported by spectroscopic
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techniques. The synthesized complexes were characterized by spectroscopic methods and their
physicochemical properties such as absorption spectra and magnetic susceptibilities were
studied.
EXPERIMENTAL SACTION
Materials
All the materials were of commercial reagent grade. The 2,5-dihydroxybenzaldehyde and
aliphatic and aromatic diamine compounds were purified by standard procedures and the purity
was determined by thin layer chromatography (TLC).
Apparatus
Melting points were taken on a Gallenkamp melting point apparatus and are uncorrected.
Uv--Vis spectra were recorded on Beckman DU-64 spectrophotometers. IR spectra were
recorded as KBr pellets on a Perkin-Elmer 781 spectrophotometer and an Impact 400 Nicolet
1
Magna series FTIR spectrophotometer. H NMR spectra was obtained at 400 MHz using a
Bruker Avance 400 NMR in CDCl3 and DMSO-d6 as the solvents. 13C NMR (100 MHz) spectra
for compounds were obtained on a 400 MHz Avance Bruker spectrometer. Mass spectra were
recorded on a Finnigan MAT 44S by Electron Ionization (EI) mode with an ionization voltage of
70 eV. The elemental analyses (C, H, N) were obtained from a Carlo ERBA Model EA 1108
analyzer. The purity determination of the substrates and reaction monitoring were accomplished
by TLC on silica-gel polygram SILG/UV 254 plates (from Merck Company).
General procedure for synthesis of the Schiff base ligands
Mixture of 2,5-dihydroxybenzaldehyde (0.35 g, 2.5 mmol) in MeOH was added to
diamine (1.4 mmol) and stirring for 5 min. The progress of the reaction was monitored by TLC.
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After reaction completion, yellow solid product was filtered off and washed with cold MeOH
and pure Schiff base was obtained. The Schiff base products were identified by physical and
spectroscopic data.
2,2'-[1,2--ethanediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3a)
[26]; Yellow solid, m.p = 286--288°C; IR (KBr), υ/cm1: 3190--3385 (s, br, 2OH), 1640 (s, C =
N), 1596, 1507 (Ar), 1217 (s, C-O); Anal. Calcd. For C. H. N: 64.0 (C), 5.3 (H), 9.3 (N); Found:
64.3(C), 5.3 (H), 9.2 (N); MS: m/z = 300 (M‏+, 2), 165 (4), 150 (18), 136 (24), 123 (88), 109 (28),
80 (65), 56 (100), 67 (87); 1H NMR (400 MHz/DMSO-d6)/δ ppm: 12.5 (br, 2OH, Intramolecular
hydrogen bonding), 8.97 (br, 2OH), 8.47 (s, 2CH Imine), 6.67--6.78 (m, 6H, Ar), 3.87 (s, 4H,
2CH2); 13C NMR (100 MHz/DMSO-d6)/δ ppm: 167.08, 153.50, 149.75, 120.37, 118.96, 117.93,
116.98, 59.50; UV/λmax: 360 (s), 260 (w).
2,2'-[1,4--butanediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3b)
[27]; Orange solid, m.p = 284--286°C; IR (KBr), υ/cm1: 3248--3400 (s, br, 2OH), 1642 (s, C =
N), 1552, 1459 (Ar), 1232 (s, C-O); Anal. Calcd. For C. H. N: 65.8 (C), 6.1 (H), 8.5 (N); Found:
65.5(C), 6.1 (H), 8.21 (N); MS: m/z = 328 (M+‏, 4), 193 (5), 178 (20), 164 (26), 151 (90), 137
1
(30), 108 (67), 84 (100), 95 (89); H NMR (400 MHz/DMSO-d6)/δ ppm: 12.7 (br, 2OH,
Intramolecular hydrogen bonding), 8.97 (br, 2OH), 8.44 (s, 2CH Imine), 6.67--6.79 (m, 6H, Ar),
3.59 (t, 4H, 2CH2, J = 10.6 Hz), 3.1 (t, 4H, 2CH2, J = 9.4 Hz); 13C NMR(100 MHz/DMSO-d6)/δ
ppm: 165.97, 154.46, 149.73, 120.20, 119.01, 116.94, 116.58, 58.76, 28.61; UV/λmax: 350 (s),
250 (w).
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2,2'-[1,6--hexanediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3c)
Yellow solid, m.p = 240--242°C; IR (KBr), υ/cm1: 3260--3550 (s, br, 2OH), 1647 (s, C = N),
1462, 1395 (Ar), 1248 (s, C-O); Anal. Calcd. For C. H. N: 67.4(C), 6.7 (H), 7.9 (N); Found: 67.3
(C), 6.6 (H), 7.9 (N); m/z = 356 (M‏+, 3), 221 (6), 206 (22), 192 (27), 179 (90), 165 (69), 136
(67), 123 (89), 112 (100); 1H NMR (400 MHz/DMSO-d6)/δ ppm: 12.8 (br, 2OH, Intramolecular
hydrogen bonding), 8.91 (br, 2OH), 8.42 (s, 2CH Imine), 6.79 (d, 2H, Ar, J = 2.4 Hz), 6.76 (dd,
2H, Ar, J1 = 8.2 Hz, J2 = 2.3 Hz), 6.69 (d, 2H, Ar, J = 8.8 Hz), 3.54 (t, 4H, 2CH2, J = 13.2 Hz),
1.6 (m, 4H, 2CH2), 1.4 (t, 4H, 2CH2, J = 12 Hz); 13C NMR(100 MHz/DMSO-d6)/δ ppm: 164.97,
153.36, 148.73, 119.20, 118.02, 117.58, 116.54, 53.10, 26.57, 25.28; MS UV/λmax: 340 (s), 250
(w).
2,2'-[1,7--heptanediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3d)
Yellow solid, m.p = 215--217°C; IR (KBr), υ/cm1: 3373--3500 (s, br, 2OH), 1646 (s, C = N),
1503, 1457 (Ar), 1239 (s, C-O); Anal. Calcd. For C. H. N: 68.1(C), 7.02 (H), 7.6 (N); Found:
68.1 (C), 6.9 (H), 7.4 (N); MS: m/z = 370 (M+‏, 4), 235 (6), 220 (22), 206 (28), 193 (90), 179
1
(32), 150 (68), 137 (92), 126(100); H NMR (400 MHz/DMSO-d6)/δ ppm: 12.7 (br, 2OH,
Intramolecular hydrogen bonding), 8.90 (br, 2OH), 8.42 (s, 2CH Imine), 6.78 (d, 2H, Ar, J = 4
Hz), 6.76 (dd, 2H, Ar, J1 = 8.2 Hz, J2 = 2.2 Hz), 6.69 (d, 2H, Ar, J = 8.4 Hz), 3.54 (t, 4H, 2CH2, J
= 12.8Hz), 1.58 (m, 8H, 4CH2), 1.33 (m, 2H, CH2); 13C NMR(100 MHz/DMSO-d6)/δ ppm:
165.77, 153.62, 149.70, 120.12, 119.01, 117.25, 116.90, 59.02, 30.83, 28.88, 27.03; UV/λmax
:
340 (s), 240 (w).
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2,2'-[1,8--octanediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3e)
Yellow solid, m.p = 220--222°C; IR (KBr), υ/cm1: 3249--3423 (s, br, 2OH), 1642 (s, C = N),
1551, 1459 (Ar), 1232 (s, C-O); Anal. Calcd. For C. H. N: 68.8(C), 7.3 (H), 7.3 (N); Found: 68.9
(C), 7.3 (H), 7.4 (N); MS: m/z = 384 (M‏+, 6), 249 (8), 234 (23), 220 (28), 207 (93), 193 (32), 164
(69), 151 (92), 140 (100); 1H NMR (400 MHz/DMSO-d6)/δ ppm: 12.59 (br, 2OH,
Intramolecular hydrogen bonding), 8.97 (br, 2OH), 8.39 (s, 2CH Imine), 6.79 (d, 2H, Ar, J = 2.4
Hz), 6.77 (dd, 2H, Ar, J1 = 8.2 Hz, J2 = 2.3 Hz), 6.70 (d, 2H, Ar, J = 8.4 Hz), 3.6 (t, 4H, 2CH2, J
= 8 Hz), 2.1 (m, 4H, 2CH2), 1.4 (m, 4H, 2CH2), 1.1 (m, 4H, 2CH2); 13C NMR(100 MHz/DMSO-
d6)/δ ppm: 165.79, 153.60, 149.69, 120.10, 119.02, 117.24, 116.89, 59.03, 30.86, 29.14, 27.05;
UV/λmax: 320 (s), 255 (w).
2,2'-[1,9--nonanediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3f)
Yellow solid, m.p = 186--189°C; IR (KBr), υ/cm1: 3325--3525 (s, br, 2OH), 1646 (s, C = N),
1545, 1460 (Ar), 1240 (s, C-O); Anal. Calcd. For C. H. N: 69.3(C), 7.5 (H), 7.03 (N); Found:
69.4 (C), 7.2 (H), 7.1 (N); MS: m/z = 398 (M+‏, 8), 263 (5), 248 (24), 234 (28), 221 (95), 207
1
(30), 178 (70), 165 (94), 154 (100); H NMR (400 MHz/DMSO-d6)/δ ppm: 12.73 (br, 2OH,
Intramolecular hydrogen bonding), 8.90 (br, 2OH), 8.42 (s, 2CH Imine), 6.79 (d, 2H, Ar, J = 9.2
Hz), 6.77 (dd, 2H, Ar, J1 = 8 Hz, J2 = 2.2 Hz), 6.69 (d, 2H, Ar, J = 8 Hz), 3.53 (t, 4H, 2CH2, J =
12.4 Hz), 1.56 (m, 4H, 2CH2), 1.28 (m, 10H, 5CH2); 13C NMR(100 MHz/DMSO-d6)/δ ppm:
165.78, 153.57, 149.72, 120.10, 119.01, 117.22, 116.88, 59.03, 30.86, 29.38, 29.12, 27.04;
UV/λmax: 340 (s), 245 (w).
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2,2'-[1,2--phenylenediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3g)
[28,29]; Red solid, m.p = 270--272°C; IR (KBr), υ/cm1: 3250--3500 (s, br, 2OH), 1619 (s, C =
N), 1572, 1488 (Ar), 1289 (s, C-O); Anal. Calcd. For C. H. N: 68.9(C), 4.6 (H), 8.04 (N); Found:
68.7 (C), 4.9 (H), 7.7 (N); MS: m/z = 348 (M‏+, 3), 212 (10), 129 (14), 92 (78), 93 (14), 80 (42),
1
77 (47), 65 (100); H NMR (400 MHz/DMSO-d6)/δ ppm: 12.13 (br, 2OH, Intramolecular
hydrogen bonding), 9.10 (br, 2OH), 8.79 (s, 2CH Imine), 7.40 (dd, 2H, Ar, J1 = 8.2 Hz, J2 = 2.3
Hz), 7.37 (dd, 2H, Ar, J1 = 8.3 Hz, J2 = 2.3 Hz), 7.02 (d, 2H, Ar, J = 2.8 Hz), 6.86 (dd, 2H, Ar, J1
= 8.1 Hz, J2 = 2.7 Hz), 6.78 (d, 2H, Ar, J = 8.8 Hz); 13C NMR(100 MHz/DMSO-d6)/δ ppm:
164.28, 153.73, 150.04, 142.98, 128.03, 121.77, 120.28, 119.88, 117.38, 117.27; UV/λmax: 360
(s), 260 (w). UV/λmax: 370 (s), 260 (w).
2,2'-[1,4--phenylenediyl-bis(nitrilomethylidene)]-bis(4-hydroxyphenol) (3h)
[48]; Orange solid, m.p = 253--256°C; IR (KBr), υ/cm1: 3150--3400 (s, br, 2OH), 1618 (s, C =
N), 1579, 1463 (Ar), 1203 (s, C-O); Anal. Calcd. For C. H. N: 68.9(C), 4.6 (H), 8.04 (N); Found:
68.6 (C), 4.9 (H), 7.7 (N); MS: m/z = 348 (M‏+, 6), 212 (10), 129 (14), 92 (78), 93 (18), 80 (46),
1
77 (47), 65 (100); H NMR (400 MHz/DMSO-d6)/δ ppm: 12.25 (br, 2OH, Intramolecular
hydrogen bonding), 9.10 (br, 2OH), 8.90 (s, 2CH Imine), 7.49 (s, 4H, Ar), 7.05 (d, 2H, Ar, J =
2.4 Hz), 6.87 (dd, 2H, Ar, J1 = 8.2 Hz, J2 = 2.4 Hz), 6.81 (d, 2H, Ar, J = 8.8 Hz); 13C NMR(100
MHz/DMSO-d6)/δ ppm: 163.15, 153.64, 149.91, 147.37, 122.92, 121.67, 119.82, 117.66,
117.42; UV/λmax: 340 (s), 258 (w).
General procedure for synthesis of the Schiff base complexes of metal(II)
To a solution of desired ligand (1 mmol) in MeOH (10 mL) was added M(O2CCH3)2 (1
mmol) dropwise at room temperature. The reaction mixture was stirred 70 minutes and the
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progress of the reaction was monitored by TLC. After completion, a colorful product was filtered
off and washed with MeOH, and the pure Schiff base complex was obtained.
2,2-(1,2-Ethanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) nickel(II) (4a)
[49]; Brown solid, m.p = 312-314°C; IR (KBr), υ/cm1: 3350-3408 (br, OH), 1618 (s, C = N),
1554, 1451 (s, Ar C = C), 1299 (s, C-O); Anal. Calcd. For C. H. N: 53.9(C), 3.9 (H), 7.9 (N);
Found: 54.1 (C), 3.8 (H), 8.02 (N); MS: m/z = 356 (M‏+, 6), 131 (4), 107 (10), 91 (100), 77 (70),
51 (95); 1H NMR (400 MHz/DMSO-d6)/δppm: 8.55 (br, 2H, 2 OH), 8.60 (s, 2CH Imine), 6.52-
13
6.73 (m, 6H, Ar), 3.15 (s, 4H, 2 CH2); C NMR (100 MHz/DMSO-d6)/δppm: 162.41, 158.66,
146.20, 124.45, 120.45, 119.60, 115.61, 64.10; UV-vis/λmax: 555 (w), 290 (s), 220 (w).
2,2-(1,7-Heptanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato)nickel(II) (4d)
Light green solid, m.p = 310-312°C; IR (KBr), υ/cm1: 3400-3430 (br, OH), 1632 (s, C = N),
1552, 1470 (s, Ar C = C), 1292 (s, C-O); Anal. Calcd. For C. H. N: 59.2(C), 5.6 (H), 6.6 (N);
Found: 59.1 (C), 5.6 (H), 6.4 (N); MS: m/z = 426 (M‏+, 4), 201 (6), 174 (14), 91 (100), 77 (72);
1H NMR (400 MHz/DMSO-d6)/δppm: 8.9 (br, 2H, 2 OH), 8.42 (s, 2CH Imine), 6.78 (d, 2H, Ar),
6.76 (dd, 2H, Ar), 6.69 (d, 2H, Ar), 3.54 (t, 4H, 2 CH2), 1.58 (m, 8H, 4 CH2), 1.33 (m, 2H, CH2);
13C NMR (100 MHz/DMSO-d6)/δppm: 165.77, 153.62, 149.70, 120.12, 119.01, 117.25, 116.90,
59.02, 30.83, 28.88, 27.03; UV-vis/λmax: 584 (w), 320 (s), 210 (w).
2,2-(1,2-Phenylenediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) nickel(II) (4g)
Dark red solid, m.p = 330-332°C; IR (KBr), υ/cm1: 3360-3418 (br, OH), 1604 (s, C = N), 1535,
1468 (s, Ar C = C), 1211 (s, C-O); Anal. Calcd. For C. H. N: 59.3(C), 3.5 (H), 6.9 (N); Found:
59.2 (C), 7.3 (H), 6.7 (N); MS: m/z = 404 (M‏+, 2), 343 (5), 289 (2), 135 (22), 109 (11), 91 (100),
1
77 (62), 65 (74); H NMR (400 MHz/DMSO-d6)/δppm: 8.83 (br, 2H, 2 OH), 8.60 (s, 2CH
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13
Imine), 7.28-8.13 (m, 4H, Ar), 6.76-6.89 (m, 6H, Ar); C NMR (100 MHz/DMSO-d6)/δppm:
160.77, 155.72, 146.80, 142.82, 127.59, 127.25, 121.07, 119.55, 116.46, 115.20; UV-vis/λmax
:
595 (w), 300 (s), 240 (w).
2,2-(1,2-Ethanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) uranyl(II) (5a)
Dark red solid, m.p = 340-342°C; IR (KBr), υ/cm1: 3350-3418 (br, OH), 1627 (s, C = N), 1560,
1442 (s, Ar C = C), 1275 (s, C-O); Anal. Calcd. For C. H. N: 59.2(C), 5.6 (H), 6.6 (N); Found:
59.1 (C), 5.6 (H), 6.4 (N); MS: m/z = 568 (M‏+, 4), 343 (4), 316 (6), 107 (12), 91 (100), 77 (68),
1
51 (96); H NMR (400 MHz/DMSO-d6)/δppm: 9.30 (br, 2H, 2 OH), 8.66 (s, 2CH Imine), 7.05
(d, 2H, Ar, J = 7.6 Hz), 6.95 (dd, 2H, Ar, J1 = 8.2 Hz, J2 = 2.3 Hz), 6.75 (d, 2H, Ar, J = 8 Hz),
4.41 (s, 4H, 2CH2); 13C NMR (100 MHz/DMSO-d6)/δppm: 168.68, 163.10, 147.98, 123.69,
123.28, 121.08, 118.53, 79.63; UV/λmax: 360 (s), 260 (w).
2,2-(1,4-Butanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) uranyl(II) (5b)
Dark red solid, m.p = 343-345°C; IR (KBr), υ/cm1: 3320-3431 (br, OH), 1634 (s, C = N), 1539,
1461 (s, Ar C = C), 1262 (s, C-O); Anal. Calcd. For C. H. N: 36.8(C), 3.0 (H), 4.7(N); Found:
36.4 (C), 3.0 (H), 4.6 (N); MS: m/z = 596 (M‏+, 2), 371 (4), 344 (5), 135 (10), 91 (100), 77 (66),
51 (96); 1H NMR (400 MHz/DMSO-d6)/δppm: 9.10 (br, 2H, 2 OH), 8.50 (s, 2CH Imine), 6.56-
6.64 (m, 6H, Ar), 4.01 (t, 4H, 2CH2, J = 10.2 Hz), 3.75 (t, 4H, 2CH2, J = 9.2 Hz); 13C NMR (100
MHz/DMSO-d6)/δppm: 165.62, 162.10, 145.93, 121.60, 122.23, 120.08, 117.50, 80.61;
UV/λmax: 365 (s), 265 (w).
2,2-(1,6-Hexanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) uranyl(II) (5c)
Dark red solid, m.p = 344-346°C; IR (KBr), υ/cm1: 3310-3448 (br, OH), 1628 (s, C = N), 1534,
1480 (s, Ar C = C), 1265 (s, C-O); Anal. Calcd. For C. H. N: 38.7(C), 3.6 (H), 4.6 (N); Found:
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38.4 (C), 3.5 (H), 4.6 (N); MS: m/z = 624 (M‏+, 4), 399 (3), 372 (4), 163 (14), 91 (100), 77 (68),
1
51 (95); H NMR (400 MHz/DMSO-d6)/δppm: 9.20 (br, 2H, 2 OH), 8.42 (s, 2CH Imine), 6.75
(d, 2H, Ar, J = 4 Hz), 6.64 (dd, 2H, Ar, J1 = 8 Hz, J2 = 2.3 Hz), 6.60 (d, 2H, Ar, J = 4 Hz), 3.41
13
(t, 4H, 2CH2, J = 8.4 Hz), 1.9 (m, 4H, 2CH2), 1.2 (t, 4H, 2CH2, J = 7.2 Hz); C NMR (100
MHz/DMSO-d6)/δppm: 166.64, 162.11, 143.90, 121.61, 124.30, 121.06, 117.53, 74.60.
UV/λmax: 330 (s), 264 (w).
2,2-(1,7-Hexanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) uranyl(II) (5d)
Dark brown solid, m.p = 345-347°C; IR (KBr), υ/cm1: 3300-3422 (br, OH), 1632 (s, C = N),
1534, 1481 (s, Ar C = C), 1264 (s, C-O); Anal. Calcd. For C. H. N: 39.3(C), 3.8 (H), 4.9 (N);
Found: 39.4 (C), 3.7 (H), 4.7 (N); MS: m/z = 638 (M‏+, 2), 413 (4), 386 (6), 177 (10), 91 (100),
1
77 (65), 51 (98); H NMR (400 MHz/DMSO-d6)/δppm: 9.15 (br, 2H, 2 OH), 8.45 (s, 2CH
Imine), 6.72 (d, 2H, Ar, J = 7.6 Hz), 6.68 (dd, 2H, Ar, J1 = 7.4 Hz, J2 = 2.1 Hz), 6.64 (d, 2H, Ar,
J = 7.4 Hz), 3.48 (t, 4H, 2 CH2, J = 10.8 Hz), 1.54 (m, 8H, 4 CH2), 1.30 (m, 2H, CH2); 13C NMR
(100 MHz/DMSO-d6)/δppm: 168.60, 163.20, 145.88, 120.66, 125.28, 123.09, 116.55, 79.68;
UV/λmax: 335 (s), 258 (w).
2,2-(1,2-Phenylenediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) uranyl(II) (5g)
Dark red, m.p = 350-352°C; IR (KBr), υ/cm1: 3350-3434 (br, OH), 1602 (m, C = N), 1548,
1472 (s, Ar C = C), 1275 (s, C-O); Anal. Calcd. For C. H. N: 38.9(C), 2.3 (H), 4.5 (N); Found:
38.6 (C), 2.3 (H), 4.4 (N); MS: m/z = 616 (M‏+, 4), 555 (6), 501 (4), 347 (25), 109 (18), 91 (100),
1
77 (64), 65 (78); H NMR (400 MHz/DMSO-d6)/δppm: 9.45 (br, 2H, 2 OH), 8.61 (s, 2CH
13
Imine), 7.50-7.51 (m, 4H, Ar), 6.79-7.13 (m, 6H, Ar); C NMR (100 MHz/DMSO-d6)/δppm:
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166.50, 164.17, 148.38, 147.22, 129.09, 125.59, 123.83, 121.47, 120.66, 119.29; UV/λmax: 340
(s), 264 (w).
2,2-(1,2-Ethanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) zinc(II) (6a)
Light green solid, m.p = 289-290°C; IR (KBr), υ/cm1: 3246-3400 (br, OH), 1638 (m, C = N),
1569, 1445 (s, Ar C = C), 1270 (s, C-O); Anal. Calcd. For C. H. N: 52.9(C), 3.8 (H), 7.6 (N);
1
Found: 52.8 (C), 3.8 (H), 7.7 (N); H NMR (400 MHz/DMSO-d6)/δppm: 8.60 (br, 2H, 2 OH),
8.53 (s, 2CH Imine), 7.01 (d, 2H, Ar, J = 7.3 Hz), 6.85 (dd, 2H, Ar, J1 = 8.1 Hz, J2 = 2.5 Hz),
6.70 (d, 2H, Ar, J = 8.4 Hz), 3.87 (s, 4H, 2CH2); 13C NMR (100 MHz/DMSO-d6)/δppm: 174.50,
166.14, 144.80, 126.70, 123.06, 118.69, 60.18, 31.23, 28.81, 27.08, 25.43; UV/λmax: 300 (s), 200
(w).
2,2-(1,9-Nonanediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) zinc(II) (6f)
Light green solid;, m.p = 298-300°C; IR (KBr), υ/cm1: 3350-3415 (br, OH), 1624 (m, C = N),
1546, 1469 (s, Ar C = C), 1283 (s, C-O); Anal. Calcd. For C. H. N: 59.9(C), 6.07 (H), 6.07 (N);
Found: 59.8 (C), 5.9 (H), 6.07 (N); MS: m/z = 461 (M‏+, 4), 236 (8), 209 (14), 91 (100), 77 (74),
51 (94); 1H NMR (400 MHz/DMSO-d6)/δppm: 8.53 (br, 2H, 2 OH), 8.48 (s, 2CH Imine), 6.48-
6.77 (m, 6H, Ar), 3.5 (t, 4H, 2CH2, J = 7.6 Hz), 1.3-2.4 (m, 14H, 7CH2); 13C NMR (100
MHz/DMSO-d6)/δppm: 171.53, 164.13, 145.88, 124.71, 123.09, 117.71, 60.23, 30.24, 28.91,
27.04, 26.45; UV/λmax: 310 (s), 205 (w).
2,2-(1,2-Phenylenediylbisnitrilomethylidine)-bis(4-hydroxyphenolato) zinc(II) (6g)
Light yellow solid, m.p = 299-302°C; IR (KBr), υ/cm1: 3400-3442 (br, OH), 1617 (m, C = N),
1547, 1473 (s, Ar C = C), 1280 (s, C-O); Anal. Calcd. For C. H. N: 66.2(C), 3.8 (H), 7.7 (N);
1
Found: 66.1 (C), 3.9 (H), 7.7 (N); H NMR (400 MHz/DMSO-d6)/δppm: 8.72 (br, 2H, 2 OH),
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8.62 (s, 2CH Imine), 7.38-8.15 (m, 4H, Ar), 6.84-6.91 (m, 6H, Ar); 13C NMR (100 MHz/DMSO-
d6)/δppm: 173.50, 163.12, 144.86, 124.68, 123.02, 116.91, 59.23, 30.20, 28.95, 27.09, 26.41;
UV/λmax: 308 (s), 208 (w).
ACKNOWLEDGEMENT
The authors are grateful to University of Kashan for supporting this work by Grant No.
159148/5.
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References
1. R. H. Holm, P. Kennepohl, E.I. Solomon, Chem. Rev., 96, 2239 (1996).
2. M. S. Karthikeyan, D. J. Prasal, B. Poojary, K. S. Bhat, B. S. Holla, N. S. Kumari, Bioorg &
Med. Chem., 14, 7482 (2006).
3. K. Singh, M. S. Barwa, P. Tyagi, Eur. J. Med. Chem., 41, 147 (2006).
4. E.I. Solomon, M.J. Baldwin, M.D. Lowery, Chem. Rev., 92, 521 (1992).
5. S. K. Sridhar, M. Saravanan, A. Ramesh, Eur. J. Med. Chem., 36, 615 (2001).
6. S. N. Pandeya, D. Sriram, G. Nath, E. DeClercq, Eur. J. Pharm. Sci., 9, 25 (1999).
7. R. Mladenova, M. Ignatova, N. Manolova, T. Petrova, I. Rashkov, Eur. Pol. J., 38, 989
(2002).
8. N. Poonia, S. Siddiqui, M. Arshad, D. Kumar, Spectrochim. Acta A Mol. Biomol.
Spectroscopy, 155, 146 (2016).
9. H. Naeimi, Z. S. Nazifi, S.M. Amininezhad, M. Amouheidari, J. Antibiotics, 66, 687 (2013).
10. R. Atkins, G. Brewer, E. Kokot, G. M. Mockler, E. Sinn, Inorg. Chem., 24, 127 (1985).
11. T. Mangamamba, M. C. Ganorkar, G. Swarnabala, Int. J. Inorg. Chem., 2014, (2014).
12. W. H. Mahmoud, R. G. Deghadi, G. G. Mohamed, Appl. Organomet. Chem., 30, 221 (2016).
13. J. Rakhtshah, S. Salehzadeh, M. A. Zolfigol, S. Baghery, J. Coord. Chem.,70, 340 (2016).
14. A. M. Abu-Dief, I. M. A. Mohamed, Beni-Suef Univ. J. Basic and Sci., 4, 119 (2015).
15. A. D. Garnovskii, A. L. Nivorozhkin, V. I. Minkin, Coord. Chem. Rev., 126, 1 (1993).
16. Z. Li, G. Liu, Z. Zheng, H. Chen, Tetrahedron, 56, 7187 (2000).
17. L. Cai, H. Mahmoud, Y. Han, Tetrahedron: Asymmetry, 10, 411 (1991).
18
ACCEPTED MANUSCRIPT

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18. C. M. Che, H. L. Kwong, W. C. Chu, K. F. Cheng, W. S. Lee, H. S. Yu, C. T. Yeung, K. K.
Cheung, Eur. J. Inorg. Chem., 2002, 1456 (2002).
19. H. B. Zhu, Z. Y. Dai, W. Huang, K. Cui, S. H. Gou, C. J. Zhu, Polyhedron, 23, 1131 (2004).
20. K. M. Gillespie, C. J. Sanders, P. O. Shaughnessy, I. Westmoreland, C. P. Thickitt, P. Scott,
J. Org. Chem., 67, 3450 (2002).
21. H. H. Monfared, Z. Kalantari, M. A. Kamyabi and C. Janiak, Zeitschrift fur Anorganische
und Allgemeine Chemie, 633, 1945 (2007).
22. R. Ziessel, Coord. Chem. Rev., 216, 195 (2001).
23. D. M. Boghaei, and M. Behzad, Synth. React. Inorg. Metal-Org. Nano-Metal Chem., 35, 261
(2005).
24. S. S. Wazalwar, N. S. Bhave, A. G. Dikundwar, and P. Ali, Synth. React. Inorg. Metal-Org.
Nano-Metal Chem., 41, 459 (2011).
25. M. Mazloum-Ardakani, N. Rajabzadeh, A. Dehghani-Firouzabadi, M. A. Sheikh-Mohseni,
A. Benvidi, H. Naeimi, M. Akbari and A. Karshenas, Anal. Meth., 4, 2127 (2012).
26. M. Kondo, K. Nabari, T. Horiba, Y. Irie, Md. K. Kabir, R. P. Sarker, E. Shimizu, Y.
Shimizu, Y. Fuwa, Inorg. Chem. Commun., 6, 154 (2003).
27. J. S. Matalobos, A. M. Garcia-Deibe, M. Fondo, D. Navarro, M. R. Bermejo, Inorg. Chem.
Commun. 7, 311 (2004).
28. P. M. Dominiak, A. Makal, P. R. Mallinson, K. Trzcinska, J. Eilmes, E. Grech, M. Chruszcz,
W. Minor and K. Woz´niak, Chem. Eur. J., 12, 1941 (2006).
19
ACCEPTED MANUSCRIPT

ACCEPTED MANUSCRIPT
29. E. H. Charles, L. M. L. Chia, J. Rothery, E. L. Watson, E. J. L. McInnes, R. D. Farley, A. J.
Bridgeman, F. E. Mabbs, Ch. C. Rowlands and M. A. Halcrow, J. Chem. Soc., Dalton
Trans.: Inorganic Chemistry, 12, 2087 (1999).
30. H. Naeimi, H. Sharghi, F. Salimi and K. Rabiei, Heteroatom Chem., 19, 43 (2008).
31. H. Naeimi and M. Moradian, Polyhedron, 27, 3639 (2008).
32. H. Naeimi, M. Moradian, J. Chem., 2013, 1 (2012).
33. H. Naeimi, F. Salimi, K. Rabiei, J. Coord. Chem., 61, 3659 (2008).
34. H. Naeimi, K. Rabiei, F. Salimi, J. Coord. Chem., 62, 1199 (2009).
35. H. Naeimi, M. Moradian, J. Coord. Chem., 63, 156 (2010).
36. H. Naeimi, Z. S. Nazifi, Chemija, 24, 197 (2013).
37. H. Naeimi, A. Karshenas, Polyhedron, 49, 234 (2013).
38. T. Kawasaki, T. Kamata, H. Ushijima, M. Kanakubo, Sh. Murata, F. Mizukami, Y. Fujii and
Y. Usui, J. Chem. Soc., Perkin Trans. 2: Phys. Org. Chem., 2, 193 (1999).
39. A. S. El-Tabl, F. A. El-Saied and A. N. Al-Hakimi, Trans. Met. Chem., 32, 689 (2007).
40. H. E. Smith, J. R. Nneergaard, E. P. Burrows and F. M. Chen, J. Am. Chem. Soc., 96, 2908
(1974).
41. J. A. Faniran, K. S. Patel and J. C. Bailar Jr, J. Inorg. and Nucl. Chem., 36, 1547 (1974).
42. H. H. Freedman, J. Am. Chem. Soc., 83, 2900 (1961).
43. A. Seminara, S. Giuffrida, A. Musumeci and I. Fragalá, Inorg. Chim. Acta, 95, 201 (1984).
44. F. Dianzhong and W. Bo, Trans. Met. Chem., 18, 101 (1993).
45. O. Kahn, “Molecular Magnetism”, VCH, New York, (1993).
46. J. A. R. Hartman, M. Y. Combariza and R. W. Vachet, Inorg. Chim. Acta, 357, 51-(2004).
20
ACCEPTED MANUSCRIPT

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47. P. V. Balkrishnan, S. K. Patil, H. D. Sharma and H. V. Venkatsetly, Can. J. Chem., 43, 2052
(1965).
48. M. Sahin, N. Kocak, G. Arslan, H. I. Ucan, J. Inorg. and Organomet. Poly. and Mat., 21, 69
(2011).
49. S. M. Kagwanja, C. J. Jones and J. A. McCleverty, Polyhedron, 16, 1439 (1997).
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Table 1. Results related to the synthesis of Schiff bases.
Entry
Substrate(Diamine)
H2N--(CH2)2--NH2
H2N--(CH2)4--NH2
H2N--(CH2)6--NH2
H2N--(CH2)7--NH2
H2N--(CH2)8--NH2
H2N--(CH2)9--NH2
o-C6H4 (NH2)2
Product
3a
Time (min)
m.p. (°C)
286-288
284-286
240-242
215-217
220-222
186-189
270-272
253-256
Yielda (%)
1
2
3
4
5
6
7
8
5
95
95
95
90
90
85
96
92
10
12
12
15
15
30
45
3b
3c
3d
3e
3f
3g
p-C6H4 (NH2)2
3h
aIsolated yields based on aldehyde.
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Table 2. The obtained results related to the synthesis of Schiff base complexes.
Entry
Substrate
Product
4a
Time (min)
m.p. (°C)
312-314
310-312
330-332
Yielda (%)
1
2
3
70
65
30
90
80
98
3a
3d
3g
4d
4g
aIsolated yields based on Schiff base.
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Table 3. The obtained results related to the synthesis of Schiff base complexes.
Entry
Substrate
Product
5a
Time (min)
m.p. (°C)
340-342
343-345
Yielda (%)
1
2
75
20
89
90
3a
3b
5b
3
25
344-346
95
3c
5c
4
5
30
40
345-347
350-352
89
90
3d
3g
5d
5g
aIsolated yields based on Schiff base.
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Table 4. The obtained results related to the synthesis of Schiff base complexes of zinc (II)
Entry
Substrate
Product
6a
Time (min)
m.p.(°C)
289-290
298-300
299-302
Yielda (%)
1
2
3
10
35
45
90
85
95
3a
3f
6f
3g
6g
aIsolated yield based on Schiff base.
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Table 5. Magnetic susceptibility measurements of the complexes
Entry
Sample
4a
χm(× 104):emu/gr.Oe
3.3586
1
2
3
4
5
6
7
8
3.4102
4d
3.6476
4g
2.0013
5a
2.1018
5b
1.9890
5c
2.1115
5d
2.0549
5g
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Fig 1. The representative biologically active Schiff base and complex.
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Fig. 2. 1H NMR spectrum of 2,2'-[1,2--phenilenediyl-bis(nitrilomethylidene)]-bis (4-
hydroxyphenol) (3g).
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Fig 3. 1H NMR spectrum of 2,2-(1,2-Phenylenediylbisnitrilomethylidine)-bis(4-
hydroxyphenolato) uranyl(II) (5g).
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