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Transition Met Chem (2012) 37:117–124
0.414 g (83%), respectively. M.p. [ 300 °C (H3L2), and
277–278 °C (H3L3). Anal. for C18H14N2O3 (%): Calcd. C
70.5, H 4.6, N 9.2; Found C 70.4, H 4.6, N 9.3 (H3L2) and C
70.5, H 4.6, N 9.2 (H3L3).
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Synthesis of Cu3L12ðpyÞ4Cl2 (1)
A solution of H2L1 (0.100 g, 0.50 mmol) in ethanol (10 mL)
was added to a solution of CuCl2ꢀ2H2O (0.090 g, 0.50 mmol)
in ethanol (10 mL). The mixture was refluxed for 3 h. The
green precipitate was filtered off. Then, a hot mixture of
pyridine/DMSO (V/V = 1:1) was used to dissolve the pre-
cipitate. The mixture was filtered, and the filtrate was covered
with anhydrous ether. Green block crystals suitable for X-ray
analysis were isolated from the filtrate after 2 weeks. Yield
0.13 g (28%). Anal. for C34H32Cl2Cu3N12O2S2 (%): Calcd. C
42.2, H 3.31, N 17.4; Found C 42.5, H 3.32, N 17.1. IR spectra
(KBr, cm-1): m = 3,395 bs, 1,637 s, 1,612 s, 1,593 m,
1,518 s, 1,384 m, 1,220 w, 751 m, 674 m, 568 m.
Scheme 1 Ligands used in this paper
Experimental
Synthesis of [Cu(HL2)py] (2)
All chemicals and solvents were commercially available
products and used without further purification. Elemental
analyses (C, H and N) were performed on a Perkin-Elmer
2400 II analyzer. FTIR spectra of the complexes were
measured on a Nicolet-460 FTIR spectrometer in the range
4,000–400 cm-1, as KBr pellets. Thermal properties were
analyzed with a Perkin–Elmer Instruction system (Pyris 1)
at a scan rate of 10 °C min-1 under nitrogen.
H3L3 (0.25 mmol, 0.076 g) and KOH (0.50 mmol, 0.028 g)
were dissolved in DMF (8 mL). After stirring for 10 min, a
solution of Cu(ClO4)2ꢀ4H2O (0.25 mmol, 0.084 g) in MeOH
(8 mL) was added. The mixture was filtered after stirring for
4 h, and pyridine (10 mL) was used to dissolve the precipi-
tate. Blue crystals were isolated from the solution after
standing in air for 1 week. Anal. for C46H34Cu2N6O6 (%):
Calcd. C 61.9, H 3.8, N 18.8; Found C 62.4, H 3.9, N 18.6.
FTIR spectra (KBr, cm-1):m = 3,423 bs, 1,638 vs, 1,612
vs, 1,576 m, 1,524 s, 1,452 m, 1,384 s, 1,361 w, 1,344 m,
1,312 m, 1,245 m, 1,221 m, 1,146 m, 1,068 m, 903 m,
873 m, 644 w, 617 w, 738 s, 694 m, 477 m.
Preparation of H2L1
H2L1 was prepared according to the literature method [15].
To a stirred solution of 2-picolinyl hydrazide (2.0 mmol,
0.274 g) in 30 mL absolute ethanol, potassium thiocyanate
(2.0 mmol, 0.194 g) and HCl (2.0 mmol) were added, the
mixture was refluxed for 12 h, then cooled to room tem-
perature. The precipitate was recrystallized from ethanol
to give H2L1 as white crystals. Yield 0.321 g (82%).
M.p. = 217–218 °C. Anal. for C7H8N4OS (%): Calcd. C
42.9, H 4.1, N 28.6; Found C 42.7, H 4.1, N 28.4.
Synthesis of [Cu(HL3)py] (3)
To a stirred solution of H3L4 (0.25 mmol, 0.077 g) and
NaOMe (0.50 mmol) in DMF (8 mL), a solution of
Cu(ClO4)2ꢀ4H2O (0.25 mmol, 0.092 g) in MeOH/pyridine
(8 mL) (V/V = 1:1) was added. The mixture was filtered
after 4 h. Dark green rectangular single crystals were iso-
lated from the filtrate after standing in air for 2 days. Anal.
for C23H17CuN3O3. Calcd. C 61.9, H 3.8, N 18.8; Found
C 61.8, H 3.8, N 18.4. FTIR spectra (KBr, cm-1):
m = 3,443 s, 3,047 w, 1,615 vs, 1,602 s, 1,527 s, 1,452 s,
1,484 s, 1,391 s, 1,334 s, 1,256 s, 1,302 m, 1,239 w,
1,138 m, 1,017 s, 971 m, 855 w, 757 vs, 747 vs, 696 s.
Preparation of H3L2 and H3L3
Both H3L2 and H3L3 were prepared by the literature method
[16]. To an ethanol (15 mL) solution of 3-hyroxy-2-naph-
thohydrazide (0.319 g, 1.58 mmol) or salicylic hydrazide
(0.267 g, 1.63 mmol), a solution of 2-hydroxybenzaldehyde
(0.192 g, 1.58 mmol) or 2-hyroxy-1-naphthaldehyde (0.280
g, 1.63 mmol) in ethanol (15 mL) was added, and the mix-
ture was refluxed for 3 h. The solution was then cooled to
room temperature and filtered. The yellow solid was washed
with cooled ethanol (5 mL). Yield 0.378 g (78%) and
X-ray crystallographic determination
Crystals of the three complexes with approximate dimen-
sions 0.38 9 0.31 9 0.23 mm (1), 0.42 9 0.21 9
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