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J Chem Crystallogr (2008) 38:781–786
Synthesis of the Ligands
799(w). Anal. Calcd for C18H20Cl2CuN10O7: C, 34.71; H,
3.24; N, 22.49 %. Found: C, 34.67; H, 3.29; N, 22.46%.
The ligand (L) was synthesized referenced the literature
method [12]: Metal Na pieces (0.598 g, 0.026 mol) were
added carefully to the solution of 3,5-bimethyl-pyrazole
(2.5 g, 0.026 mol) in dry THF (75 mL) under N2 protect-
ing. The reaction mixture was stirring for 30 min, 3,6-
bichloropyridazine (3.87 g, 0.026 mol) was added to the
reaction mixture mentioned above. The reaction mixture
was refluxing for 4 h, it was filtered. The filtrate was re-
crystallized in methanol to isolate the L, yield: 68.6%.
Anal. Calcd for C9H9N4Cl (mol. Wt. 208.5): C, 51.81; H,
4.35; N, 26.85. Found: C, 51.76; H, 4.39; N, 26.80. IR.
(KBr pellets, cm-1): 3201 m, 3143(s), 3093(m), 3052(m),
2982(m), 2929(m), 1574(m), 1539(m), 1427(s), 1361(m),
1137(m), 1084(s), 972(m), 855(m), 790(m), 742(w),
507(w).
X-ray Crystallography
The crystals of two copper(II) complexes were mounted on
a glass fiber, respectively. Determination of the unit cell
and data collection were performed using MoKa radiation
´
(k = 0.71073 A) on a Bruker SMART 1000 diffractometer
equipped with a CCD camera. The x - 2h scan technique
was employed. The structures were solved primarily by
direct methods and secondly by Fourier difference tech-
niques and refined using the full-matrix least-squares
method. The computations were performed with the
SHELXS-97 and the SHELXL-97 programs [13]. All non-
hydrogen atoms were refined anisotropically. All the
hydrogen atoms were located on the calculated positions
and refined as riding atoms with a common fixed isotropic
thermal parameter. Crystal parameters and structure
refinements for the compounds are summarized in Table 1.
The molecular structure of the ligand L is shown as
Chart 1.
Synthesis of [Cu(L)2(CH3OH)] ꢀ (ClO4)2 (1)
Results and Discussion
A solution of Cu(ClO4)2 ꢀ 6H2O (0.37 g, 0.1 mmol) in
methanol (5 mL) was added dropwise to the methanol
solution (5 mL) of L (0.1 mmol), which was continuously
stirring for 30 min. The reaction mixture was filtered, and
the filtrate was kept to stand for over 3 weeks. The green
single crystals of 1 suitable for X-ray analysis were
obtained, yield: 60%. IR (KBr pellets, cm-1): 3453(br),
3118(w), 1584(m), 1482(m), 1425(s), 1276(w), 1075(s),
835(m), 799(m), 627(m), 523(w). Anal. Calcd for
C19H22Cl4CuN8O9: C, 32.06; H, 3.12; N, 15.74%. Found:
C, 32.01; H, 3.16; N, 15.70%.
Description of the Structures
[Cu(L)2(CH3OH)] ꢀ (ClO4)2 (1). The perspective view of 1
is given in Fig. 1. The selected bond lengths and angles are
summarized in Table 2.
From the Fig. 1, it can be seen that the coordination
configuration of the Cu(II) atom is best described a trigonal
bipyramidal configuration with the bond angles being N(1)–
Cu(1)–O(1) = 87.45°, N(1A)–Cu(1)–O(1) = 93.18°, N(3)–
Cu(1)–O(1) = 100.63° and N(3A)–Cu(1)–O(1) = 130.86°,
which has be tested by Addision s rule [14] (s = 0.9387
indicates the configuration is closed the idea trigonal bi-
pyramid). The mean plane is defined by O(1), N(3) and
N(3A), N(1) and N(1A) occupy the apical sites with the bond
angle N(1)–Cu(1)–N(1A) = 176.9°. The total bond angles
of N(3)–Cu(1)–N(3A) = 128.51°, N(3)–Cu(1)–O(1) =
100.63° and N(3A)–Cu(1)–O(1) = 130.86° is 360°, which is
shown that Cu(1) atom is in the mean plane. Two molecules
of 1 are linked by the weaker intermolecular action through
perchlorate ion in l-O,O model to present a binuclear
structure (Fig. 2). The data of the inter-molecular action is
summarized in Table 3.
Synthesis of [Cu(L)2(H2O)] ꢀ (NO3)2 (2)
Running the same procedure as that of 1, except
Cu(NO3)2 ꢀ 3H2O instead of Cu(ClO4)2 ꢀ 6H2O. The blue
green single crystals of 2 suitable for X-ray analysis were
isolated, yield: 42%. IR. (KBr pellets, cm-1): 3460(br),
3096(w), 1626(w), 1583(m), 1478(m), 1425(s), 1382(s),
1209(w), 1161(m), 1122(m), 1074(w), 997(m), 840(m),
[Cu(L)2(H2O)] ꢀ (NO3)2 (2). The molecular configura-
tion of 2 is quite similar to that of 1 except a H2O
coordinated instead of CH3OH coordinated (Fig. 3), and
the selected bond distances and angles are summarized in
Table 4. There is weaker interaction between 2 and NO3-
ion in the unit cell of 2 (Fig. 4). The Cu(L)2(H2O)2+ ions
are linked by the intermolecular hydrogen bond to form a
N
Cl
N
N
N
Chart 1 The molecular structure of L
123