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L.-J. Tang et al. / Journal of Inorganic Biochemistry 105 (2011) 1623–1629
citrate at pH 7.0. Then this solution was exhaustively stirred at 4 °C
for 3 days, and kept at 4 °C for no longer than a week. The ratio of
UV absorbance at 260 and 280 nm (A260/A280) given by the stock
solution of CT DNA was 1.89, indicating that the DNA was sufficiently
free of protein contamination. The DNA concentration was deter-
filtered and washed with methanol, followed by being washed with
distilled water to remove inorganic selenium. The selenium com-
pound b was then dried in vacuum freeze-drying.
The ethanol solution of ligand a (0.270 g, 0.001 mol in 30 mL eth-
anol) was adjusted to pH 8–9 by addition of triethylamine. The mix-
ture was stirred at 40 °C for 2 h under nitrogen protection, followed
by introducing hydrated metal (II) salt (acetate or chloride)
(0.001 mol) slowly via syringe which was dissolved in ethanol
(10 mL). The reaction mixture was stirred at 60 °C for 24 h, and
then stood at room temperature for 2 days. Powered solids were
yielded by filtration, rinsed with ethanol and dried under vacuum.
b. SeO(a-2H), Yield 0.51 g, 44.44%. m.p.N300 °C. Anal. Calcd. for b:
mined by the UV absorbance at 260 nm using ε=6,600 M−1 cm−1
.
The slit's width was 10 nm, and fluorescence pool thickness was 1 cm.
Melting points were recorded on a XP4 Electrothermal melting
point apparatus without being corrected. Infrared spectra were mea-
sured on a 670 FT-IR spectrophotometer equipped with an MCT de-
tector and a diffuse reflectance accessory [23].using the KBr pellet
technique (4000–400 cm−1). EI-MS were obtained from an Esquire
HCT instrument in the positive/negative mode. Compounds were dis-
solved in DMSO: methanol (1:1). 1H NMR spectra were recorded on a
Bruker Avance-600 using dimethyl sulfoxide-d6 (DMSO-d6) as sol-
vent. Elemental analyses were performed on a PE-2400-II Elemental
Analyzer. Molar conductivity (Λ) was measured on DDS-11A model
digital conductivity meter based on the measurements designed by
Geary [24]. A long-term UV–VIS study was carried out to verify the
stability of new complexes in DMSO/water solution. The result of
antitumor screening was measured at 570 nm on a microplate spec-
trophotometer (Bio-Tek Instruments, ELx808zu, USA).
C
15H8O6Se (%): C, 49.59; H, 2.20; Se, 21.75. Found (%): C, 49.56; H,
2.11; Se, 21.92. IR (KBr): 3118 (υO\H), 1606 (υC_O), 1538–1328
(υC_C), 1206 (υC\O\H), 1172 (υC\O\C), 696 (υSe\O) cm−1 1H-
.
NMR (600 MHz, DMSO-d6): 6.73 (2H, d, 3′,5′-H), 7.00 (1H, d, 6-H),
7.21 (2H, d, 2′,6′-H), 7.38 (1H, d, 5-H), 8.30 (1H, s, 2-H), 10.15 (1H,
s, 4′-OH) ppm. Λ=4.6 S·cm2·mol−1
.
c. Zn(a-H)2, Yield 0.16 g, 53.2%. m.p.N300 °C. Anal. Calcd. for c:
C30H18O10Zn (%): C, 59.66; H, 2.98; Zn, 10.84. Found (%): C, 59.46;
H, 2.76; Zn, 10.94. IR (KBr) υ: 3347 (υO\H), 1608 (υC_O), 1558–
1387 (υC_C), 1206 (υC\O\H), 1174 (υC\O\C) cm−1 1H-NMR
.
(600 MHz, DMSO-d6): 5.69 (4H, d, 3′, 5′, L3′, L5′-H), 6.76 (2H, d, 6,
L6-H), 7.02 (4H, d, 2′, 6′, L2′, L6′-H), 7.35 (2H, s, 5, L5-H), 8.39 (2H,
s, 2, L2-H), 9.83 (2H, s, 7, L7′-OH),10.25 (2H, s, 4, L4′-OH) ppm.
2.2. Synthesis of ligand 7,8,4′-trihydroxy-isoflavone, a
The reaction of pyrogallic acid (2.25 g, 0.02 mol) and p-
hydroxyphenylacetic acid (2.84 g, 0.02 mol) was carried out in
boron trifluoride etherate (BF3·Et2O solvent and catalyst) (20 mL)
with nitrogen protection. The reaction mixture was stirred at 80 °C for
3 h. Then TLC-point board was used to monitor the reaction progress
till the resulting deoxy benzoin intermediate point (Rf≈0.17, agent
for the ethyl acetate: petroleum ether=1:2) was not changed.
Sequentially the N, N-dimethylformamide (DMF) (30 mL) was
added dropwise to the mixture of deoxybenzoin which had been
cooled to room temperature. The obtained solution was then cooled
to 10 °C. In another flask, DMF (54 mL) was cooled to 10 °C and
methylsulfonyl chloride (MeSO2Cl) (14 mL) was added in small por-
tions. The mixture was then allowed to stand at 55 °C for 30 min
and added to the above reaction mixture slowly. During the addition,
the temperature of the reaction mixture was maintained below 27 °C.
The mixture was then stirred at room temperature for 4 h. The fol-
lowing work-up was sequentially carried out: pouring the reaction
mixture into methanolic HCl (0.1 mol) followed by heating at 70 °C
for 20 min (the reaction progress was monitored by TLC and the Rf
of ligand a showed 0.07, agent for the ethyl acetate: petroleum
ether=1:2), and extracting the product by acetoacetate after remov-
ing the methanol and most of DMF. The solvent was removed under
vacuum using a rotary evaporator and product was purified by
recrystallization.
Λ=5.2 S·cm2·mol−1
.
d. Cu(a-H)2, Yield 0.19 g, 63.3%. m.p.N300 °C. Anal. calcd. for d:
30H18O10Cu (%): C, 59.82; H, 2.99; Cu, 10.56. Found (%): C, 60.16;
C
H, 2.92; Cu, 10.56. IR (KBr) υ: 3371 (υO\H), 1608 (υC_O), 1567–
1387 (υC_C), 1236 (υC\O\H), 1174 (υC\O\C) cm−1 1H-NMR
.
(600 MHz, MSO-d6): 6.77 (4H, d, 3′, 5′, L3′, L5′-H), 7.34 (2H, d, 6,
L6-H), 7.99 (4H, d, 2′, 6′, L2′, L6′-H), 8.09 (2H, s, 5, L5-H), 8.27 (2H,
s, 2, L2-H), 9.43 (2H, s, 7, L7′-OH),10.36 (2H, s, 4, L4′-OH) ppm.
Λ=2.8 S·cm2·mol−1
.
e. Mn(a-H)2, Yield 0.16 g, 54.1%. m.p.N300 °C. Anal. calcd. for e:
30H18O10Mn (%): C, 60.71; H, 3.03; Mn, 9.26. Found (%): C, 61.02;
C
H, 2.96; Mn, 9.15. IR (KBr) υ : 3399 (υO\H), 1608 (υC_O), 1558–
1386 (υC_C), 1222 (υC\O\H), 1174 (υC\O\C) cm−1 1H-NMR
.
(600 MHz, DMSO-d6): 5.31 (4H, d, 3′, 5′, L3′,L5′-H), 5.68 (2H, d, 6,
L6-H), 6.97 (4H, d, 2′, 6′, L2′, L6′-H), 7.47 (2H, s, 5, L5-H), 8.34 (2H,
s, 2, L2-H), 9.54 (2H, s, 7, L7′-OH),10.32 (2H, s, 4, L4′-OH) ppm.
Λ=4.3 S·cm2·mol−1
.
f. Ni(a-H)2, Yield 0.16 g, 53.8%. m.p.N300 °C. Anal. calcd. for f:
30H18O10Ni (%): C, 60.33; H, 3.02; Ni, 9.84. Found (%): C, 60.66; H,
C
2.88; Ni, 9.79. IR (KBr) υ: 3347 (υO\H), 1608 (υC_O), 1558–1387
(υC_C), 1206 (υC\O\H), 1173 (υC\O\C) cm−1 1H-NMR
.
(600 MHz, DMSO-d6): 5.31 (4H, s, 3′, 5′, L3′, L5′-H), 5.88 (2H, s, 6,
L6-H), 6.49 (4H, d, 2′, 6′, L2′, L6′-H), 7.47 (2H, d, 5, L5-H), 8.34 (2H,
s, 2, L2-H), 9.49 (2H, s, 7, L7′-OH),10.11 (2H, s, 4, L4′-OH)
a: C15H10O5, Yield 2.4 g, 46.3%. m.p. 280–282 °C. Anal. Calcd. for a:
ppm.Λ=9.0 S·cm2·mol−1
.
C
15H10O5 (%): C, 66.67; H, 3.70; Found (%): C, 66.59; H, 3.69; IR (KBr):
3470 (υO\H), 1621 (υC_O), 1582–1441 (υC_C), 1280 (υC\O\H),
1175 (υC\O\C) cm−1 1H NMR (600 MHz, DMSO-d6, d=doublet,
g. Co(a-H)2, Yield 0.15 g, 53.8%. m.p.N300 °C. Anal. calcd. for g:
30H18O10Co (%): C, 60.31 H, 3.02; Co, 9.87. Found (%): C, 60.38; H,
C
.
3.01; Co, 10.03. IR (KBr) υ: 3346 (υO\H), 1608 (υC_O), 1558–1380
s=singlet): 6.81 (2H, d, 3′,5′-H), 6.95 (1H, d, 6-H), 7.38 (2H, d,
2′,6′-H), 7.47 (1H, d, 5-H), 8.34 (1H, s, 2-H), 9.42 (1H, s, 8-OH), 9.51
(1H, s, 7-OH), 10.29 (1H, s, 4′-OH) ppm.
(υC__C), 1206 (υC\O\H), 1173 (υC\O\C) cm−1 1H-NMR
.
(600 MHz, DMSO-d6): 5.81 (4H, d, 3′, 5′, L3′, L5′-H), 6.38 (2H, s, 6,
L6-H), 6.95 (4H, d, 2′, 6′, L2′, L6′-H), 7.46 (2H, s, 5, L5-H), 8.44 (2H,
s, 2, L2-H), 9.23 (2H, s, 7, L7′-OH),10.43 (2H, s, 4, L4′-OH)
2.3. Synthesis of complexes
ppm.Λ=8.9 S·cm2·mol−1
.
A
pyridine solution (5 mL) of selenium oxychloride (about
2.4. Biological studies
3.3 mmol) was added to the pyridine solution of 7, 8, 4′-trihydroxy-
isoflavone (ligand a, 3.3 mmol in 20 mL dry pyridine). The mixture
was stirred at 50 °C for 6 h under nitrogen protection till ligand a
point disappeared completely and only one point observed through
the TLC monitoring. Gradually, the light brown solid precipitated
when being cooled to room temperature. The solid products were
2.4.1. Antibacterial activity
The synthesized compounds were tested for their antibacterial
activities by means of standard double dilution method using
agar media [25]. The assayed collection included the following
microorganisms: ATCC25923, Staphylococcus aureus 701230, S.