Y. An et al. / Inorganica Chimica Acta 376 (2011) 230–237
231
a 25 mL flask. The reaction mixture was stirred at room tempera-
ture for 4 h and filtered to give a colorless solution in the beaker.
The resulted solution was kept in the dark and colorless crystals
suitable for X-ray analysis formed at the bottom of the beaker after
5 days. Yield: 50.5%.
S
S
(
)
n
R
O
R
L1: n = 1, R = pyridyl; L2: n = 2, R = pyridyl;
L3: n = 1, R = benzothiazyl; L4: n = 2, R = benzothiazyl
Scheme 1. Structures of the ligands used in the study.
2.3.3. [AgL3(NO3)] (3)
1
A solution of AgNO3 (17.0 mg, 0.1 mmol) in MeOH (5 mL) was
added to a solution of L3 (40.4 mg, 0.1 mmol) in CHCl3 (5 mL) in
a 25 mL flask and white powder formed immediately. Yield:
63.5%. Single crystals suitable for X-ray analysis were obtained
by recrystallization the powder from MeOH/CHCl3/DMF.
tained as
a
colorless liquid. Yield: 76.6%. 1H NMR (CDCl3,
400 MHz): d 3.357–3.394 (m, 4H), 3.717–3.750 (m, 4H), 6.904–
6.944 (m, 2H), 7.131–7.159 (m, 2H), 7.390–7.437 (m, 2H), 8.361–
8.371 (m, 2H). 13C NMR (CDCl3, 400 MHz): d 29.13, 69.71, 119.24,
122.14, 135.71, 149.26, 158.29. ESI-MS: m/z 293.2 [L1H+]. IR (KBr,
m
, cmꢀ1): 3045m, 2929m, 2857m, 1578vs, 1553s, 1454s, 1414vs,
2.3.4. [AgL4(NO3)] (4)
1356m, 1285m, 1122vs, 1042w, 986w, 758s, 722m.
A solution of AgNO3 (17.0 mg, 0.1 mmol) in MeOH (5 mL) was
added to a solution of L4 (44.8 mg, 0.1 mmol) in CHCl3 (5 mL) in
a 25 mL flask. The reaction mixture was stirred at room tempera-
ture for 4 h and filtered to give a colorless solution in the beaker.
The resulted solution was kept in the dark and colorless crystals
suitable for X-ray analysis formed at the bottom of the beaker after
10 days. Yield: 58.5%.
2.2.2. 1,2-Bis(2-(pyridin-2-ylthio)ethoxy)ethane (L2)
L2 was obtained from the reaction of 1,2-bis(2-chloroeth-
oxy)ethane and pyridine-2-thiol with the similar procedure as
described above. Yield: 59.5%. 1H NMR (CDCl3, 400 MHz): d
3.380–3.414 (t, 4H), 3.658–3.660 (d, 4H), 3.731–3.764 (t, 4H),
6.931–6.962 (m, 2H), 7.156–7.178 (m, 2H), 7.422–7.464 (m, 2H),
8.390–8.402 (m, 2H). 13C NMR (CDCl3, 400 MHz): d 29.08, 70.12,
70.14, 119.24, 122.13, 135.72, 149.28, 158.35. ESI-MS: m/z 337.1
[L2H+]. IR (KBr,
m
, cmꢀ1): 3045w, 2927m, 2864s, 1578vs, 1558s,
2.4. X-ray crystallography
1454vs, 1415vs, 1353w, 1285m, 1122vs, 1043w, 986w, 760s, 722m.
Single-crystal X-ray diffraction measurements of complex 1 was
carried out on a Bruker Smart 1000 CCD diffractometer operating
2.2.3. Bis(2-(benzothiazol-2-ylthio)ethyl)ether (L3)
A solution of bis(2-chloroethyl)ether in ethanol was added
dropwise to a hot mixture solution of 2-mercaptobenzothiazole,
KOH in ethanol (100 mL), and the mixture was further stirred at
80 °C for 15 h. After cooling down, the precipitate was filtered,
washed with ethanol and water, and recrystallized from ethanol
to obtain white powder. Yield: 56%. 1H NMR (CDCl3, 400 MHz): d
3.56 (t, 4H), 3.89 (t, 4H), 7.25 (m, 2H), 7.39 (m, 2H), 7.70 (d, 2H),
7.82 (t, 2H). 13C NMR (CDCl3, 400 MHz): d 32.79, 69.30, 120.88,
121.38, 124.16, 125.92, 135.19, 153.02, 166.34. ESI-MS: m/z
at 50 kV and 30 mA using Mo K
a radiation (k = 0.71073 Å), and
data collection using the SMART and SAINT software. An empirical
absorption correction was applied using the SADABS program. While
the data of complexes 2, 3 and 4 were collected at 293 K using an
Oxford Xcalibur
S
diffractometer with Cu
K
a
radiation
(k = 1.54184 Å). Data collection, integration and scaling of the
reflections were performed by means of the CRYALIS suite of pro-
grams. All the structures of complexes 1–4 were solved by direct
methods with SHELXS97 [23] and refined by the full-matrix least-
squares method on all F2 data suing the SHELXL-97 [24] programs.
All non-hydrogen atoms were refined with anisotropic displace-
ment parameters. The hydrogen atoms were added theoretically
and riding on the concerned atoms. Crystallographic data and
experimental details for structure analyses are summarized in
Table 1.
405.0 [L3H+]. IR (KBr,
m
, cmꢀ1): 3049w, 2903m, 2861m, 1483w,
1458s, 1427vs, 1310w, 1239m, 1102vs, 1034m, 997vs, 752vs, 723m.
2.2.4. 1,2-Bis(2-(benzothiazol-2-ylthio)ethoxy)ethane (L4)
L4 was obtained from the reaction of 1,2-bis(2-chloroeth-
oxy)ethane and 2-mercaptobenzothiazole with the similar proce-
dure as described for L3. Yield: 46.3%. 1H NMR (CDCl3, 400 MHz):
d 3.538–3.570 (t, 4H), 3.668 (s, 4H), 3.841–3.873 (t, 4H), 7.237–
7.275 (t, 2H), 7.360–7.399 (t, 2H), 7.700–7.720 (d, 2H), 7.829–
7.849 (d, 2H). 13C NMR (CDCl3, 400 MHz): d 32.84, 69.56, 70.37,
120.87, 121.38, 124.11, 125.90, 135.21, 153.08, 166.43. ESI-MS:
2.5. Antimicrobial activities of the complexes
The bioactivities of the four complexes were assessed by their
ability to inhibit the growth of P. tricornutum in a medium (pH
8.3) containing filtered artificial sea water (30 g/L of commercial
salts), Na2HPO4 (4.4 mg/L), NaNO3 (74.8 mg/L), Na2SiO3 (16.7 mg/
L), CuSO4ꢁ5H2O (10 mg/L), CoCl2ꢁ6H2O (12 mg/L), MnCl2ꢁ4H2O
(178 mg/L), V2MoO4ꢁ2H2O (7.3 mg/L), Na2–EDTA (4.35 g/L), vita-
m/z 449.1 [L4H+]. IR (KBr,
m
, cmꢀ1): 3059w, 2929w, 2887m,
2865m, 2812w, 1487w, 1457s, 1425vs, 1321m, 1281m, 1236m,
1125vs, 994vs, 753s, 728m.
2.3. Preparation of complexes
min B1 (100 mg/L), vitamin B12 (0.5 mg/L) and vitamin
(0.5 mg/L). The water was of Milli-Q quality (Millipore).
H
2.3.1. [Ag2L1(NO3)2]2 (1)
A solution of AgNO3 (34.0 mg, 0.2 mmol) in MeOH (5 mL) was
added to a solution of L1 (29.2 mg, 0.1 mmol) in CHCl3 (5 mL) in
a 25 mL flask and white powder formed immediately. Yield:
56.2%. Single crystals suitable for X-ray analysis were obtained
by recrystallization the powder from MeOH/CHCl3/DMF.
Erlenmeyer flasks (250-mL) were inoculated with 100 ml
(2.50 ꢂ 106 cell/mL) of a mother diatom culture. The microalgae
were grown under a light–dark cycle (12 h/12 h, illumination: fluo-
rescent tubes, 4000–6000 lux) in a phytotron thermostated at
18 1 °C.
Different concentrations of the complex (0, 50, 100, 150, 200,
250 lg/L) were applied the 4th day after inoculation (exponential
2.3.2. [Ag2L2(NO3)2] (2)
A solution of AgNO3 (34.0 mg, 0.2 mmol) in MeOH (5 mL) was
phase). Measurements were performed 96 h after the complex
addition.
added to a solution of L2 (33.6 mg, 0.1 mmol) in CHCl3 (5 mL) in