Synthesis and characterization of a novel quinoxaline-substituted vic-dioxime and its complexes containing bis(12-diazacrown-4) derivatives

Article abstract of DOI:10.1246/bcsj.80.1549

A new quinoxaline-substituted vicinal dioxime ligand containing bis( 12-diazacrown-4) units (H₂L) was synthesized by the reaction of cyanogen di-N-oxide with compound 4. Mononuclear Ni^II and Cu ^II complexes with a metal: ligand ratio of 1:2 for H₂L and a trinuclear Cu^II complex were also synthesized. The mononuclear Cu^II species coordinated to two Cu^II ions through the deprotonated oximate oxygens to yield a trinuclear structure cis-bridged by the ox-imate groups, with 1,10-phenanthroline as an end-cap ligand. The mononuclear Co^III complex of H₂L was isolated with pyridine and chlorine as axial ligands. In addition, a Co^III complex containing the BF₂⁺ bridge macrocycle was synthesized using a precursor hydrogen-bridged Co^III complex via a template effect. The extraction abilities of 1, 3, and 11 were also evaluated in 1,2-dichloroethane by using several alkali (Li⁺, Na⁺, K⁺, and Cs⁺) and transition-metal picrates, such as Ag⁺, Pb ²⁺, Cd²⁺, Cu²⁺, and Zn²⁺. Structures of the ligands and metal complexes were solved by elemental analyses, ¹H and ¹³CNMR, FT-IR, UV-vis, and mass spectra.

Full text of DOI:10.1246/bcsj.80.1549

Ó 2007 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 80, No. 8, 1549–1555 (2007) 1549
Synthesis and Characterization of
a Novel Quinoxaline-Substituted vic-Dioxime and
Its Complexes Containing Bis(12-Diazacrown-4) Derivatives
ꢀ1
2
3
¨
Ahmet Bilgin, Beytullah Ertem, and Yasꢀar Gok
1Department of Science Education, Kocaeli University, 41300 Kocaeli, Turkey
2Department of Chemistry, Karadeniz Technical University, 61080 Trabzon, Turkey
3Department of Chemistry, Pamukkale University, Kꢀnꢀklꢀ Campus 20070 Kꢀnꢀklꢀ/Denizli, Turkey
Received December 12, 2006; E-mail: abilgin@kou.edu.tr
A new quinoxaline-substituted vicinal dioxime ligand containing bis(12-diazacrown-4) units (H2L) was synthe-
sized by the reaction of cyanogen di-N-oxide with compound 4. Mononuclear NiII and CuII complexes with a metal:
ligand ratio of 1:2 for H2L and a trinuclear CuII complex were also synthesized. The mononuclear CuII species coordi-
nated to two CuII ions through the deprotonated oximate oxygens to yield a trinuclear structure cis-bridged by the ox-
imate groups, with 1,10-phenanthroline as an end-cap ligand. The mononuclear CoIII complex of H2L was isolated with
þ
pyridine and chlorine as axial ligands. In addition, a CoIII complex containing the BF2 bridge macrocycle was synthe-
sized using a precursor hydrogen-bridged CoIII complex via a template effect. The extraction abilities of 1, 3, and 11
were also evaluated in 1,2-dichloroethane by using several alkali (Liþ, Naþ, Kþ, and Csþ) and transition-metal picrates,
such as Agþ, Pb2þ, Cd2þ, Cu2þ, and Zn2þ. Structures of the ligands and metal complexes were solved by elemental
1
analyses, H and 13C NMR, FT-IR, UV–vis, and mass spectra.
vic-Dioximes and their complexes have been widely investi-
gated as analytical reagents,1 models for biological systems
such as vitamin B12,2–4 compounds having columnar stacking
which is thought to be the reason for their semiconducting
properties,5 and recently, reagents in macrocyclization reac-
tions.6–8 Due to the presence of mildly acidic hydroxy groups
and slightly basic nitrogen atoms, vic-dioximes are amphoteric
ligands, which form corrin-type square-planar, square-pyrami-
dal, and octahedral complexes with transition-metal cations,
such as NiII, CuII, CoII, and CoIII as central atoms.9,10 vic-Di-
oxime metal complexes, which began an area of coordination
chemistry, have been widely explored during the past century.9
Since that time, several quasi-macrocyclic and BF2þ-capped
oximes have been synthesized.11,12 Incorporation of a vic-di-
oxime moiety on the macrocyclic provides an efficient binding
site for transition-metal ions by formation of an MN4 core with
two additional hydrogen bridges.13 Investigations of the redox
properties of these types of complexes are also of great interest
in terms of their various technological applications.14–17 In pre-
vious papers, the synthesis of vic-dioxime ligands and their
transition-metal complexes containing macrobicyclic deriva-
tives,18 monoaza crown ethers,19 dithiadiazamacrocycles,20
and diazacrown groups21 have been reported.
tionalization. Azacrown ethers thus modified have found appli-
cations in areas such as phase-transfer catalysis,23 selective
ion transport,24 resolution of chiral molecules,25 and to some
extent, the study of electron transport.22c
In the present work, we report the synthesis and characteri-
zation of a (E,E)-dioxime containing bis(diazadioxa-12-crown-
4 ethoxy) units and NiII, CuII, and CoIII complexes of H2L. A
trinuclear CuII complex and a CoIII complex containing the
þ
BF2 bridge macrocycle were synthesized as well. In addition,
alkali and heavy metal extraction abilities of 1, 3, and 11 were
also examined.
Results and Discussion
Dinitro derivative
3 was synthesized in 91% yield
(Scheme 1). The high yield obtained in this synthesis was
attributed to the template effect of sodium cations. All spectral
and physical data are in good accord with product 3.
Amino derivative 4 was obtained from compound 3 as
described in experimental section in 87.5% yield. This method
is more advantageous than the others;20 therefore, it was pre-
ferred. Amine derivative 4 was used for the following reaction
without any further purification, because amino derivatives
often decompose easily by light and heat. As it can be seen
from experimental results, the synthesis were very satisfactory.
Novel quinoxaline substituted vic-dioxime ligand (H2L)
was synthesized from the reaction of compound 4 and cyano-
gen di-N-oxide 5 in yield 65%. In the 1H NMR spectrum
of H2L, a single chemical shift for OH protons indicates that
the oxime groups are in the anti form.21,26 In the proton-decou-
pled 13C NMR of H2L, the carbon resonance of azomethine
The incorporation of nitrogen atoms into the macrocycle of
crown ethers substantially extends the range of metallic and
organic cations, with a high degree of specificity for particular
cations dependent upon ring size and the nature of the hetero-
atoms that form complexes with such compounds.22 Another
useful property of nitrogen-containing crown ethers is that they
provide considerable possibilities for relatively easy N-func-
Published on the web August 10, 2007; doi:10.1246/bcsj.80.1549

1550 Bull. Chem. Soc. Jpn. Vol. 80, No. 8 (2007)
Quinoxaline-Fused vic-Dioxime and Its Complexes
O
O
O
S
O
H3C
N
N
N
N
H3C
S
N
N
N
n-Butanol
Ar(g)
Reflux
I
O
O
O
O
S
O
O
NO2
NO2
O
O
NO2
NO2
O
O
NH2
NH2
O
O
O
O
Na2CO3
CH3CN
Ar(g)
H C
3
N
N H
2
+
NH2 NH2
10% Pd/C
O
O
O
S
O
S
I
H3C
H3C
N
O
O
O
O
1
2
3
4
O
N
CH2Cl2
Ar(g)
-10 °C
N
O
5
O
O
S
H
H
H3C
N
N
N
N
H
N
O
N
O
O
O
O
O
N
H
N
O
O
S
H3C
O
O
H2L
NiCl2·6H2O
Ethanol
Reflux
Ar(g)
Or
·
CuCl2 2H2O
Et3N
O
O
O
S
O
S
H
M
H
H3C
N
N
N
N
N
N
N
CH3
H
N
O
N
O
N
H
N
O
O
O
O
O
O
O
O
O
N
H
N
O
N
O
N
H
O
O
S
O
S
H3C
N
CH3
O
O
M: Ni, Cu
O
O
7
8
THF Cu(NO3)2 3H2O
Reflux
O
O
N
N
O
S
O
Cu
M
H3C
N
N
N
N
S
CH3
H
O
O
H
N
O
O
O
N
N
N
O
O
O
O
O
(NO3)2
O
N
H
N
O
N
O
N
H
O
O
S
O
S
H3C
N
N
N
CH3
N
Cu
O
O
N
N
O
O
M:Cu
9
Scheme 1. Synthesis of H2L and its mono- and trinuclear complexes.
group was found at lower field (151.1 ppm), and this unique
signal for the oxime groups confirms the anti form of the vic-
dioxime.19 In the IR spectrum of H2L, N–H, O–H, C=N, and
N–O stretching vibrations were observed at 3385, 3245, 1638,
and 938 cmꢁ1, respectively. These values are in agreement
with the previously reported vic-dioxime derivatives.18–21,26
Mononuclear, [Ni(HL)2] (7) and [Cu(HL)2] (8) complexes
H2L coordinates to NiII and CuII cations in N,N0 fashion. Addi-
tionally, the disappearance of the signals for OH groups of H2L
at 1451 and 3245 cmꢁ1 and the appearance of peaks at 1710
and 1729 cmꢁ1 indicate that intramolecular hydrogen bonds
form in compounds 7 and 8. A singlet was observed at ꢀ 16.68
in the 1H NMR spectrum of square-planar complex 7, showing
the existence of intramolecular hydrogen bonds (O–H O)
ꢂꢂꢂ
were prepared from H2L and stoichiometric amount of NiCl2
6H2O and CuCl2 2H2O, respectively, in ethanol (Scheme 1).
which can be easily observed deuterium-exchange method.
We also synthesized a trinuclear CuII complex, [Cu(L)2-
(Cuphen)2](NO3)2 (9), (Scheme 1) with (LH)2Cu as the bridg-
ing ligand and 1,10-phenanthroline (phen) as an end-cap
ligand. The secondary ions corresponding to the loss of two
phenanthroline ligands together with two Cu and two nitrates
ꢂ
ꢂ
Both elemental analysis and FAB mass spectral data showed
that metal:ligand ratio was 1:2 for compounds 7 and 8. That
C=N stretching vibrations of compounds 7 and 8 were lower
than stretching vibration of H2L (1638 cmꢁ1) proving that

A. Bilgin et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 8 (2007) 1551
O
O
S
H
H3C
N
N
N
N
H
N
O
N
O
O
O
O
O
2
N
H
N
O
O
S
H3C
H
O
O
H2L
CoCl2·6H2O
Ethanol
Pyridine
O2(g)
60 °C
O
O
O
S
O
H
L'
H3C
N
N
N
N
N
N
N
N
S
CH3
H
O
N
O
N
H
N
O
O
O
O
N
O
O
O
O
O
O
Co
N
H
N
O
N
O
N
H
O
S
Cl
H
O
S
H3C
CH3
O
O
O
O
10 (L': Pyridine)
CH3CN
Ar(g)
Reflux
BF3O(CH2CH3)2
O
O
O
O
S
F
F
B
L'
H3C
S
N
N
N
N
CH3
H
N
O
N
O
N
H
O
O
O
N
O
O
O
O
O
Co
O
N
H
N
O
N
O
N
H
O
O
S
Cl
B
O
S
H3C
N
N
N
CH3
N
F
F
O
O
O
O
11 (L':Pyridine)
Scheme 2. Synthesis of complexes 10 and 11.
appeared at m=z ¼ 1924:6 ½M ꢁ (CuphenNO3)2ꢃþ. In the IR
Stretching vibrations of O–H functional group at 3245 cmꢁ1
of H2L disappeared, and a new peak was observed at 1718
cmꢁ1, which indicates of the existence of intramolecular
hydrogen bonds. Broad C=N stretching vibration of com-
pound 10 at 1624 cmꢁ1 was lower than stretching vibration
of H2L (1638 cmꢁ1) proving that H2L coordinates to CoIII.
BF2-bridged CoIII complex 11 was obtained in high yield
68% at moderate dilution (0.2 mmol) with hydrogen-bridged
CoIII complex 10 and boron trifluoride etherate (0.4 mmol)
linking reagents (Scheme 2). This reagent readily reacted with
spectrum of 9, no absorption attributable to a ꢁ(O–H O)
ꢂꢂꢂ
vibration in the region 1600–2000 cmꢁ1 indicates that the
enolic hydrogen atoms are lost upon chelation. The stretching
vibration, observed at 1645 cmꢁ1, was assigned to the C=N
bond. This ꢁ(C=N) vibration of the oxime for the trinuclear
complex containing divalent metal cations was at a frequency
significantly higher than that of the free ligand. This is in
accord with the concept that, on trinuclear complex formation,
the positively charged Cu(phen)2þ unit stabilizes the negative
charge on oxygen of the oximate function and thus increases
the double bond character of the C=N bond.27 In addition,
the O–H O bridge in the precursor molecule, yielding an
ꢂꢂꢂ
extremely stable compound containing two O–BF2–O bridges,
and the axial pyridine ligand was retained, according to
1H NMR and IR spectra and elemental analysis data of 11.
In the IR spectrum of the BF2þ-capped CoIII complex, the
C=N stretching region can be used to distinguish between
the dihydrogen-bridged compound and the diboron-bridged
compounds. This BF2-macrocycle exhibited upward shifts of
ca. 35 cmꢁ1 due to the strong electron-withdrawing influence
of the BF2 groups incorporated in the macrocycle. The weak
IR spectroscopy indicates the presence of uncoordinated
nitrate ions at 1375 cmꢁ1
28
.
Mononuclear CoIII complex, [Co(HL)2PyCl] (10), was pre-
pared from H2L, pyridine and an equivalent amount of
CoCl2 6H2O in the presence of ethanol (Scheme 2). Accord-
ꢂ
ing to elemental analysis data, the metal:ligand ratio was 1:2
for this complex and also pyridine and chlorine ligands were
in axial positions of octahedral complex 10. The singlet peak
at ꢀ 16.72 in 1H NMR spectrum of octahedral complex 10
indicates the existence of intramolecular hydrogen bonds
and broad band at 1718 cmꢁ1, corresponding the O–H O
ꢂꢂꢂ
in-plane deformation of the short hydrogen bond, disappeared
upon encapsulation of the H-bonded complex, and peaks
appeared around 1156–1030 and 871–840 cmꢁ1 for the B–O
(O–H O), which were verified using deuterium-exchange.
Furthermore, chemical shifts for pyridine at ꢀ 7.92, 7.52, and
6.98 indicate the existence of an octahedral complex 10.
ꢂꢂꢂ
1
and B–F groups, respectively.29 In the H NMR spectrum of

1552 Bull. Chem. Soc. Jpn. Vol. 80, No. 8 (2007)
Quinoxaline-Fused vic-Dioxime and Its Complexes
Table 1. Alkaline and Heavy Metal Picrate Extractions from Aqueous Solutions into 1,2-Dichloroethane by Using 1, 3, and 11a)
Percent of metal picrate extracted/%b)
Host
Liþ
Naþ
Kþ
Csþ
Agþ
Zn2þ
Cd2þ
Cu2þ
Pb2þ
molecule
1
3
11
9:3 ꢄ 0:1 42:3 ꢄ 0:1 22:6 ꢄ 0:1 0:4 ꢄ 0:1 39:1 ꢄ 0:1 27:5 ꢄ 0:1 18:6 ꢄ 0:1 36:7 ꢄ 0:1 11:8 ꢄ 0:1
12:9 ꢄ 0:1 71:1 ꢄ 0:1 42:3 ꢄ 0:1 0:9 ꢄ 0:1 63:8 ꢄ 0:1 39:1 ꢄ 0:1 27:4 ꢄ 0:1 50:6 ꢄ 0:1 24:2 ꢄ 0:1
16:8 ꢄ 0:1 77:6 ꢄ 0:1 56:3 ꢄ 0:1 4:1 ꢄ 0:1 73:9 ꢄ 0:1 43:7 ꢄ 0:1 36:5 ꢄ 0:1 60:3 ꢄ 0:1 37:4 ꢄ 0:1
a) Temperature 25 ꢄ 1 ꢅC; aqueous phase (10 mL), [picrate] ¼ 3:0 ꢆ 10ꢁ3 M; organic phase (1,2-dichloroethane, 10 mL), [host
molecule] = 3:0 ꢆ 10ꢁ3 M. b) Average and standard deviation for three independent measurements.
the BF2þ-capped macrocycle, the deuterium exchangeable
hydrogen-bridged protons belonging to the H-bonded pseudo-
macrocyclic precursor CoIII complex were no longer present
after the formation of the BF2 bridge.19
To the best of our knowledge, no extraction studies involv-
ing heavy metal cations compounds containing bis(diaza-12-
crown-4) moieties except our earlier work21 have been report-
ed. One of our objectives was to investigate and perform such
a sort of study. However, there are some reports about the
extraction studies involving macrotricyclic molecules. Accord-
ing to these studies, molecules having diaza-12-crown-4 sub-
units form dinuclear complexes with AgI, ZnII, and CuII. They
can also form mononuclear complexes with other cations, such
as HgII, PbII, and CdII.30
Aza-crown ethers form stable complexes with Agþ cation
by replacement of O atoms with N atoms in crown ether moie-
ties.31c As it can be seen from the Table 1, Agþ could be ex-
tracted the best because of the formation of M2L-type com-
plexes, i.e., more diaza-12-crown-4 units are available to bind
to more cations that have small cation diameter. Also, the com-
pounds having diaza-12-crown-4 units form ML-type com-
plexes with the cations having bigger cation diameter. It means
there are less diaza-12-crown-4 units per cation. Thus, the ex-
traction capabilities of aza-crown ethers are lower for larger
cations. In addition, from the data in Table 1, the aza-crown
ether’s ability to extract sodium and silver picrate are closely
parallel. This can be attributed to the similarity in the diam-
eters of Naþ and Agþ cations.
Solvent Extraction of Alkali and Heavy Metal Cations.
In this work, besides the synthesis and characterization of a se-
ries of the new quinoxaline-substituted vicinal dioxime ligand
H2L and related complexes, we also investigated the alkali and
heavy metal ion binding properties of the compounds having
diaza-12-crown-4 units by solvent extraction of alkali and
heavy metal picrates from the aqueous to an organic phase
(Table 1). For comparison, the values obtained under the same
conditions for N-tosyldiazadioxa-12-crown-4 (1) are included
in Table 1. In addition to compound 3, since the introduction
of BF2 groups to complex 10 leads to an increase in the solu-
bility, in addition to the bulky diazacrown units, the BF2-
bridged CoIII complex 11 was used as a host. In the case of
these host compounds, it might be expected that the capability
of extracting lithium ion would be the highest among the alkali
metal cations on comparing its size to the cavity size, because
the diameter of the lithium ion is much more compatible with
12-membered macrocyclic units. However, the extraction was
highest for the sodium ion due to the bis-crown effect. In other
words, the sodium cation forms a sandwich-type complex by
being bound between two diazacrown units with a metal:ligand
ratio of 1:2. The capability of extraction for alkali metal
cations increased with compounds 1, 3, and 11. However, this
increase was not so noteworthy as compared to the increase
in the 12-membered macrocyclic units. This might be due to
steric hindrance of the bulky diaza-12-crown-4 units.
In the course of this work, we compared extraction capabili-
ties of two similar products: one is derived from nitro21 and
other one is derived from dinitro compound. We were not
able to investigate extraction capability of H2L, because of its
moderate solubility under these conditions. Comparing 3 in
this work to similar product 3 from our earlier work,21 it is ob-
vious that extraction capability of nitro derivative21 is higher
than that of dinitro derivative. Dinitro derivative 3 has two
nitro functional groups, which have an electron-withdrawing
effect greater than that of nitro derivative and decrease the
donor character of the compound, causing a decrease in extrac-
tion capability as compared to the related nitro derivative.21
If we compare the BF2-bridged CoIII complexes 10 from our
earlier work21 and 11 in our present work, the results are simi-
lar. Extraction capability increased with the number of N-
tosyldiazadioxa-12-crown-4 units that can coordinate with
more cations. Complex 1021 has more N-tosyldiazadioxa-12-
crown-4 units than complex 11, and therefore, its extraction
capability is higher than that of 11.
Conclusion
In the course of this study, new precursor materials 3, 4, a
new vic-dioxime ligand H2L, containing bis(diaza-12-crown-
4) moieties, and its [NiII, CuII, trinuclear CuII, CoIII, and
BF2-briged CoIII] complexes were synthesized in good yields
and characterized. In addition, their cation-binding properties
were evaluated using a solvent extraction technique and com-
pared to our earlier work. The hosts from our earlier work
have higher cation-binding capacities than those in this work.
Picrate was used as counter anion all compounds.
The results obtained from the extraction experiments of
alkali and heavy metal picrates indicated that the extraction ca-
pability of 11, among bis(diaza-12-crown-4) moieties studied,
was the best. The cation-binding abilities of 1, 3, 11 for Naþ
among alkali metals and Agþ among heavy metals were found
to be the highest. The alkali and heavy metal ions extracting
capabilities of bis(diaza-12-crown-4) moieties synthesized in
this work follow the order 11 > 3 > 1.
Experimental
Melting points were obtained on an electrothermal melting
point apparatus and were uncorrected. The 1H, 13C NMR, and
IR spectra were recorded on a Varian XL-200 spectrometer and
on a Perkin-Elmer Spectrum One spectrometer with the samples

A. Bilgin et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 8 (2007) 1553
in KBr pellets, respectively. The UV–vis spectra were recorded
with a model Shimadzu 1601 UV–vis spectrometer using a 10
mm pathlength cell. Mass spectra were measured on a Varian
MAT 711 and on Micromass Quatro LC/ULTIMA LC-MS/MS
spectrometers using m-nitrobenzyl alcohol as the matrix. Elemen-
tal analysis of the compounds was determined on a CHNS-932
LECO instrument. The metal content of the complexes was deter-
mined with a Unicam 929 AA spectrophotometer.
Materials. 1,2-Bis(2-iodoethoxy)-4,5-dinitrobenzene,31 4-[(4-
methylphenyl)sulphonyl)]-1,7-dioxa-4,10-diazacyclododecane,32
and cyanogen di-N-oxide33 were prepared according to the litera-
ture procedures. Reagent grade chemicals were used as received.
Solvents were purified according to standard methods34 before
use. Silica gel (70–230 mesh) was used for chromatographic
separations.
(NH2, bending), 1595, 1542, 1471, 1362, 1277, 1162–1031, 913,
713, 698, 639. 1H NMR (CDCl3): ꢀ 7.75 (d, 4H, TsArH), 7.36
(d, 4H, TsArH), 6.36 (s, 2H, Ar–CH), 4.45 (br s, 4H, NH2), 3.98
(t, 4H, Ar–O–CH2), 3.80 (m, 16H, CH2CH2OCH2CH2), 3.36
(m, 16H, –CH2N), 2.75 (t, 4H, CH2N), 2.40 (s, 6H, Ar–CH3).
MS (FAB positive): m=z 849.2 [M]þ.
H2L (6). A cold solution ꢁ10 ꢅC of cyanogen di-N-oxide (5),
which was prepared from anti-dichloroglyoxime (0.35 g, 2.24
mmol) in dichloromethane (35 mL) and an aqueous solution of
Na2CO3 (25 mL, 0.5 M), was added to a cold solution of com-
pound 4 (1.90 g, 2.24 mmol) in dichloromethane (200 mL). The
reaction was continued for 18 h at the same temperature and then
evaporated to dryness. The crude product was crystallized from a
dichloromethane/ethanol mixture (9:1) to yield pale brown crys-
tals. Yield: 1.36 g (65%); mp 182–184 ꢅC (dec). Anal. Found: C,
53.82; H, 6.64; N, 11.78%. Calcd for C42H60N8O12S2: C, 54.07;
H, 6.48; N, 12.02%. IR (KBr, cmꢁ1): 3385 (N–H), 3245 (O–H),
3082–3042, 2922–2857, 1638 (C=N), 1610, 1597, 1522, 1493,
1451, 1370, 1245, 1160–1015, 938 (N–O), 816, 714, 698, 549.
1H NMR (DMSO-d6): ꢀ 10.30 (s, 2H, OH), 8.90 (s, 2H, NH),
7.69 (d, 4H, TsArH), 7.42 (d, 4H, TsArH), 6.91 (s, 2H, ArH),
4.12 (t, 4H, Ar–O–CH2), 3.87 (m, 16H, CH2CH2OCH2CH2),
3.38 (m, 16H, –CH2N), 2.75 (t, 4H, CH2N), 2.36 (s, 6H, Ar–
CH3). 13C NMR (DMSO-d6): ꢀ 151.1 (C=N–O–H), 147.2, 144.6,
142.7, 136.4, 131.2, 128.2, 104.8, 70.2 (ArOC), 68.2–67.9
(OCH2), 53.5 (NCH2), 49.6 (NCH2CH2OAr), 21.6 (CH3–Ar).
MS (FAB positive): m=z 933.2 [M]þ.
1,2-Bis(2-{40-[40-(methylphenyl)sulphonyl]-10,70-dioxa-40,100-
diazacyclododecane}ethoxy)-4,5-dinitrobenzene (3). A three-
necked flask fitted with a condenser was charged with finely
ground anhydrous Na2CO3 (3.18 g, 30.00 mmol), compound 1
(1.968 g, 6.00 mmol), anhydrous NaI (0.45 g, 3.00 mmol), and
dry acetonitrile (90 mL), then evacuated, refilled three times with
argon, and connected to a vacuum line. Under argon, the mixture
was stirred at 45 ꢅC for 30 min. Compound 2 (1.524 g, 3.00 mmol)
was added to this mixture under argon, and the reaction mixture
was heated and stirred at 95 ꢅC for 6 days. The reaction mixture
was cooled to room temperature, and the precipitate was filtered
off and washed with dichloromethane (25 mL). The filtrate and
washes were combined, and the solvent was evaporated. The
orange residue was dissolved in chloroform (7 mL), and ethanol
was added until precipitation was first seen. The solution was then
kept inside the refrigerator for overnight. The orange crystals that
formed were collected by filtration and dried in vacuo. Yield:
2.48 g (91%); mp 290 ꢅC. Anal. Found: C, 52.65; H, 6.44; N,
9.03%. Calcd for C40H56N6O14S2: C, 52.86; H, 6.21; N, 9.25%.
IR (KBr, cmꢁ1): 3045, 2928–2860, 1599, 1580–1540, 1463, 1380,
[Ni(HL)2] (7). A solution of NiCl2 6H2O (12 mg, 0.05 mmol)
ꢂ
in ethanol (5 mL) was added to a solution of H2L (93 mg,
0.1 mmol) in ethanol (25 mL) at 60 ꢅC. A distinct change in color
and a decrease in the pH of the solution (pH 2.39) was observed.
While heating and stirring at the same temperature, ethanolic
triethylamine (0.1 M, 2.74 mL) was added in order to increase
pH 4.5–5.0. After heating the reaction mixture for 2 h in a water-
bath, the precipitate was filtered off, and washed several times
with water, ethanol, and diethyl ether, and then, orange-colored
product was dried in vacuo over P2O5. Yield: 80 mg (84%); mp >
300 ꢅC. Anal. Found: C, 52.18; H, 6.34; N, 11.79; Ni, 3.29%.
Calcd for C84H118N16O24S4Ni: C, 52.47; H, 6.19; N, 11.66; Ni,
3.06%. IR (KBr, cmꢁ1): 3385 (N–H), 3060–3018, 2970–2829,
1
1275–1229, 1123–1040, 770, 743, 651. H NMR (CDCl3): ꢀ 7.81
(d, 4H, Ar–H), 7.53 (d, 4H, Ar–H), 7.40 (s, 2H, Ar–H), 4.08 (t,
4H, Ar–O–CH2), 3.77 (m, 16H, OCH2), 3.29 (m, 16H, NCH2),
2.78 (t, 4H, NCH2CH2OAr), 2.48 (s, 6H, Ar–CH3). 13C NMR
(CDCl3): ꢀ 149.6 (ArCO), 145.8, 143.2, 134.7, 129.7, 127.1,
106.6, 69.3 (ArOC), 68.9–68.4 (OCH2), 54.4 (NCH2), 49.8
(NCH2CH2OAr), 21.0 (CH3–Ar). MS (FAB positive): m=z 931.4
½M þ Naꢃþ, 908.6 [M]þ.
1710 (O–H O), 1622 (C=N), 1610, 1598, 1506–1449, 1380,
1276–1230, 1160–1025, 939 (N–O), 822, 713, 643. 1H NMR
ꢂꢂꢂ
(DMSO-d ): ꢀ 16.68 (s, 2H, O–H O), 8.42 (br s, 4H, NH),
ꢂꢂꢂ
6
1,2-Bis(2-{40-[40-(methylphenyl)sulphonyl]-10,70-dioxa-40,100-
7.74 (d, 8H, TsArH), 7.35 (d, 8H, TsArH), 6.90 (s, 4H, ArH),
4.20–4.12 (m, 8H, Ar–O–CH2), 3.95–3.84 (m, 32H, CH2CH2O-
CH2CH2), 3.29–2.74 (m, 40H, –CH2N), 2.39 (s, 12H, Ar–CH3).
MS (FAB positive): m=z 1922.3 ½M þ 1ꢃþ.
diazacyclododecane}ethoxy)-4,5-diaminobenzene (4).
Com-
pound 3 (2.48 g, 2.73 mmol) was dissolved in n-butanol (125
mL) at 60 ꢅC under argon atmosphere and degassed on a vacuum
line. Pd/C (10%) (0.160 g) was added to reaction mixture, and
the mixture was heated at 150 ꢅC. Hydrazinium hydrate (100%)
(6.42 mL) was added to this mixture dropwise over 30 min while
refluxing. The reaction mixture was filtered through Celite after
10 h and washed several times with n-butanol. The filtrate and
washes were combined, and the solvent was evaporated to dryness
under reduced pressure. Diethyl ether was added to the residue
under argon, and the solution was kept in the dark, because the
amino derivative can decompose. Little amount of amino deriva-
tive 4 was kept for IR, 1H NMR, 13C NMR, elemental analysis,
and mass spectrums. Amine derivative 4 was used for the follow-
ing reaction without any further purification. Yield: 2.03 g
(87.5%); mp 244–246 ꢅC. Anal. Found: C, 56.24; H, 7.30; N,
9.63%. Calcd for C40H60N6O10S2: C, 56.58; H, 7.12; N, 9.90%. IR
(KBr, cmꢁ1): 3406–3290 (NH2), 3060–3032, 2980–2852, 1613
[Cu(HL)2] (8). A solution of CuCl2 2H2O (9 mg, 0.05 mmol)
ꢂ
in ethanol (5 mL) was added to a solution of H2L (93 mg, 1 mmol)
in ethanol (25 mL) at 60 ꢅC. A distinct change in color and a de-
crease in the pH of the solution (pH 2.41) was observed. While
heating and stirring at the same temperature, ethanolic triethyl-
amine (0.1 M, 3.12 mL) was added in order to increase the pH
to 5.0–6.0. After heating the reaction mixture for 2 h in a water-
bath, the precipitate was filtered off and washed several times with
water, ethanol, and diethyl ether, and then black-colored crystals
were dried in vacuo over P2O5. Yield: 136 mg (76%); mp >
300 ꢅC. Anal. Found: C, 52.92; H, 6.12; N, 11.62, Cu, 3.92%.
Calcd for C84H118N16O24S4Cu: C, 52.33; H, 6.18; N, 11.63, Cu,
3.30%. IR (KBr, cmꢁ1): 3390 (N–H), 3054–3021, 2940–2872,
1729 (O–H O), 1620 (C=N), 1598, 1508–1446, 1373, 1245,
1170–1010, 941. MS (FAB positive): m=z 1927.6 ½M þ 1ꢃþ.
ꢂꢂꢂ

1554 Bull. Chem. Soc. Jpn. Vol. 80, No. 8 (2007)
Quinoxaline-Fused vic-Dioxime and Its Complexes
[Cu(HL)2(CuL0)2](NO3)2 (9).
Complex 8 (0.482 g, 0.25
11 were investigated under liquid–liquid phase and neutral condi-
tions by using alkaline (Liþ, Naþ, Kþ, and Csþ) and heavy metal
picrates (Agþ, Pb2þ, Cd2þ, Cu2þ, and Zn2þ) as subsrates and mea-
suring UV–vis the amounts of metal picrate in the aqueous phase
before and after treatment with related compounds. Alkali metal
picrates (3 ꢆ 10ꢁ5 M) were prepared by mixing alkali metal hy-
droxides and picric acid in deionized water, whereas heavy metal
picrates were prepared by mixing metal nitrates and picric acid
in deionized water. We also prepared 3 ꢆ 10ꢁ3 M solutions of
related compounds (1, 3, and 11) in 1,2-dichloroethane. Then,
equal volumes of both metal picrate solutions and compound solu-
tions were added into plastic bottles, and the bottles were kept
closed, and shaken for 12 h by shaker at 25 ꢄ 1 ꢅC. Finally, we
took the aqueous phase and measured their absorbance at maxi-
mum wavelength (ꢇ350 nm). For each combination of host and
metal picrate, the picrate extraction was conducted on three differ-
ent samples, and the average value of percent picrate extracted,
with standard deviation, was calculated. The picrate extraction re-
sults are presented in Table 1. In the absence of host, blank ex-
periment, no metal ion picrate extraction was detected. The ex-
tractability was determined based on the absorbance of picrate ion
in the aqueous solutions. The extractability was calculated by
using below equation;
mmol) was suspended in THF (50 mL). A solution of 1,10-phen-
anthroline (0.099 g, 0.55 mmol) in THF (10 mL) and a solution of
Cu(NO3)2 3H2O (0.133 g, 0.55 mmol) in the same solvent (10
ꢂ
mL) were added to the above-mentioned suspension at reflux.
The mixture was stirred and heated at reflux for 6 h under argon
atmosphere. After that, the mixture was filtered, and the volume
of filtrate was reduced to 5–10 mL on a rotary evaporator, and
diethyl ether was slowly added with continuous stirring to the
precipitated complex. The dark green product was filtered off,
washed with water, ethanol, and diethyl ether, and dried in vacuo
at room temperature. Yield: 0.152 g (24%); mp > 300 ꢅC. Anal.
Found: C, 51.57; H, 5.12; N, 11.85, Cu, 7.92%. Calcd for
C
108H132N22O30S4Cu3: C, 51.13; H, 5.24; N, 12.15, Cu, 7.52%.
IR (KBr, cmꢁ1): 3395 (N–H), 3065, 3054–3020, 2980–2870, 1645
(C=N), 1598, 1506–1448, 1375 (NO3), 1245 (Ar–O), 1130–
1019 (C–O), 930 (N–O). MS (FAB positive): m=z 2535.3 [M]þ,
1924.6 ½M ꢁ (CuphenNO3)2ꢃþ.
[Co(HL)2L0Cl] (10).
A solution of CoCl2 6H2O (24 mg,
ꢂ
0.1 mmol) in ethanol (10 mL) was added to a solution of H2L
(186 mg, 0.2 mmol) in ethanol (75 mL) at 60 ꢅC by bubbling oxy-
gen through the solution of H2L. After 30 min, pyridine (0.01 mL,
0.1 mmol) in ethanol (5 mL) was added to mixture. Reaction mix-
ture was heated and stirred for 6 h, while oxygen passing through
it. Total volume of the residue was decreased to 1/4, and then pre-
cipitate was filtered off, washed several times with water, ethanol,
and diethyl ether. Brown-colored product was then dried in vacuo
over P2O5. Yield: 114 mg (56%); mp > 300 ꢅC. Anal. Found: C,
52.14; H, 6.28; N, 11.85; Co, 3.12%. Calcd for C89H123N17O24-
S4CoCl: C, 52.47; H, 6.08; N, 11.69; Co, 2.89%. IR (KBr,
Eð%Þ ¼ ½ðAbefore ꢁ AafterÞ=Abeforeꢃ ꢆ 100;
ð1Þ
where Abefore is the absorbance in the absence of ligand and
Aafter denotes the absorbance in the aqueous solution phase after
extraction.
This study was supported by The Scientific & Technical
Research Council of Turkey (TUBITAK), Project Number:
TBAG-2453(104T065) (Ankara, Turkey) and the Research
Fund of Karadeniz Technical University, Project Number:
2002.111.2.8 (Trabzon/Turkey).
cmꢁ1): 3340 (N–), 3060, 3045, 2930–2890, 1718 (O–H O),
ꢂꢂꢂ
1624 (C=N), 1601, 1597, 1549–1510, 1374, 1286–1226, 1159–
1
1020, 943. H NMR (DMSO-d ): ꢀ 16.72 (s, 2H, O–H O), 8.25
ꢂꢂꢂ
6
(br s, 4H, NH), 7.92 (d, 2H, py–H), 7.64 (m, 8H, TsArH), 7.52
(t, 2H, py–H), 7.32 (m, 8H, TsArH), 6.98 (t, 1H, py–H), 6.87
(s, 4H, ArH), 4.24–4.06 (m, 8H, Ar–O–CH2), 3.98–3.87 (m,
32H, CH2CH2OCH2CH2), 3.37–2.69 (m, 40H, –CH2N), 2.36 (s,
12H, Ar–CH3). MS (FAB positive): m=z 2037.8 ½M þ 1ꢃþ.
[Co(LBF2)2L0Cl] (11). A suspension of complex 10 (0.407 g,
0.2 mmol) in freshly distilled acetonitrile (100 mL) was brought to
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