4
64
X.-Y. Liu et al. / Inorganica Chimica Acta 423 (2014) 462–468
2
.5. Synthesis of [Mn(L)(
l
1,3-N(CN)
2
)]
n
(1)
3. Results and discussion
A methanol solution (15 ml) containing NaN(CN)
.0 mmol) and H L (168.5 mg, 0.5 mmol) was added to a methanol
O (181 mg, 0.5 mmol) with
stirring for about 12 h at room temperature. Dark brown cubic
crystals were obtained. Yield: 38% based on Mn(III). Anal. Calc.
2
(89 mg,
3.1. Synthesis and general characterization
1
2
solution (10 ml) of Mn(ClO
)
4 2
ꢁ6H
2
It is a popular strategy to use the cyanide groups as bridging
ligands for synthesizing the molecule-based magnets due to the
high electric charge density on both donor atoms. In the context,
ꢀ
for C18
Found: C, 47.25; H, 2.59; N, 15.31%. IR (KBr)
s), 2156 (s), 1615 (vs), 1558 (m), 1475 (vs), 1448 (s), 1385 (vs),
H
12
5
Cl2MnN O
2
(M
r
= 456.17): C, 47.39; H, 2.65; N, 15.35.
we choose two kinds of cyanide groups including N(CN) and
2
3
ꢀ
m
s
: 2887 (m), 2286
Co(CN) as well as corresponding tetradentate Schiff base ligand
6
(
2
(H L) for the explore of the magnetic coupling rule. Compounds
1
359 (s), 1249 (s), 809 (s), 689 (s), 632 (m).
1 and 2 were synthesized by using the method of slow evaporation
of the resulting methanol or ethanol solution. In compound 1, the
ꢀ
N(CN)
2
group adopts l1,3 bridging modes. Additionally, Mn(II)
2 2
2.6. Synthesis of {[Mn (L) (H
2
O)
2 2 2 6 n
]K(H O) Co(CN) } (2)
ions were oxidized to Mn(III) ions in the synthetic processes of 1
and 2.
A solution of K Co(CN)
3
6
(332.32 mg, 1.0 mmol) and triethyl-
amine (50.5 mg, 0.5 mmol) in 20 ml of mixing solvent (methanol/
water 4:1) was added dropwise to a methanol solution (10 ml) of
3.2. FTIR spectra
[
1
Mn(L)(H
2 4
O)]ClO (255 mg, 0.5 mmol) with stirring for about
2 h at room temperature. The resulting solution was filtered,
For compounds 1 and 2, the IR spectra in the range 2242–
ꢀ
1
and the filtrate was kept a week in 50 ml beaker. The brown bulk
crystals were obtained, washed with water and dried in air. Yield:
3
(
2
2286 cm exhibits strong and sharp peaks assigned to the asym-
metric and symmetric stretching vibrations of the cyanide groups.
ꢀ
1
8% based on Mn(III). Anal. Calc. for C38
= 1106.45): C, 41.25; H, 2.91; N, 12.66. Found: C, 41.18; H,
.89; N, 12.59%. IR (KBr) : 3300 (w), 2869 (m), 2279 (s), 2125
H32Cl
4
CoKMn
2
N
10
O
8
The characteristic absorption bands in the range 1612–1628 cm
confirm the presence of C@N bands in the Schiff-base, and an
M
r
ꢀ
1
m
s
intense and broad peak at 2900–3100 cm corresponds to the
(
8
s), 1612 (vs), 1532 (m), 1436 (vs), 1448 (s), 1382 (vs), 1258 (s),
19 (s), 693 (s), 665 (m).
stretching vibrations of the @CAH band in compounds 1 and 2.
ꢀ1
Moreover, a broad peak at 3300 cm has been observed, which
represent the OAH stretching vibration of water molecule in com-
pound 2.
2
.7. X-ray data collection and crystallography
3.3. Crystal structure of compound 1
Diffraction data for 1 and 2 were collected on a Bruker
Smart Apex II CCD diffractometer equipped with graphite mono-
chromated Mo K radiation (k = 0.71073 Å) using and a scan
mode at 296(2) K. Absorption correction were applied using the
The structure of compound 1 crystallizes in orthorhombic space
a
x
group P2
N(CN) -bridging. There is only one crystallographically indepen-
dent Mn(III) ion coordinated by the N donor atoms from one
1 1 1 1,3
2 2 , which consists of several 1D chains with the l -
2
SADABS program. Their structures were solved by direct methods
2 2
O
and refined with full-matrix least-squares refinements based on
2
H L ligand in the equatorial plane and two N donor atoms from
2
F
using SHELXS-97 and SHELXL-97 [39,40]. All non-hydrogen
ꢀ
two N(CN)
2
anions in the axial positions, producing a distorted
atoms were refined with anisotropic displacement parameters.
Crystal data and structure refinement details for 1 and 2 are sum-
marized in Table 1, selected bond lengths and angles are shown in
Table S1.
octahedral geometry, as shown in Fig. 1. Normally, nearly coplanar
O(1), O(2), N(1) and N(2) atoms from H L connect to the Mn(III) ion
2
in the equatorial plane exhibiting nearly identical MnAO (1.874 Å)
and MnAN (1.981 Å) bond lengths. The axial bond length between
Mn(III) ion and N atoms from
2
l1,3-N(CN) groups is 2.386 Å. This
case probably attributes to the Jahn–Teller effect at the high-spin
4
Table 1
d
metal center, which is commonly observed in octahedral
Crystal data and structure refinement summary for compounds 1 and 2.
Mn(III)-containing compounds [41]. As shown in Fig. 2(a),
N(CN)
monomeric [Mn(L1)] units, generating an extended 1D helical
chain along the crystallographic b direction (Fig. 2(b)). The nearest
ꢀ
2
ligand adopts l1,3-bridging mode to connect to adjacent
Compound
1
2
+
Empirical formula
Formula weight
Crystal system
Space group
a (Å)
C
18
H
12
C
l2MnN
5
O
2
C
38 4 2 10 8
H32Cl CoKMn N O
456.17
orthorhombic
P2
10.7881 (18)
11.5713 (19)
16.461 (3)
90
1106.45
monoclinic
P2 /c
10.675 (2)
13.996 (3)
14.975 (3)
90
94.029 (4)
90
2231.9 (8)
1,3
distance between intrachain Mn(III) centers bridged by trans-l -
1
2
1
2
1
1
b (Å)
c (Å)
a
(°)
b (°)
(°)
90
90
c
3
V (Å )
2054.9 (6)
Crystal size (mm)
0.1 ꢂ 0.1 ꢂ 0.1
0.12 ꢂ 0.11 ꢂ 0.09
Z
D
4
2
calc (Mg m 3
ꢀ
)
1.474
920
1.646
1116
F(000)
R
int
0.0581
3881/0/253
1.007
0.0958
4437/6/298
1.095
Data/restraints/parameters
Goodness-of-fit (GOF) on F2
Final R indices [I > 2
r(I)]
R
1
= 0.0473,
wR = 0.1104
= 0.0733,
wR = 0.1365
R
1
= 0.1038,
wR = 0.2177
= 0.1563,
wR = 0.2533
2
2
R indices (all data)
R
1
R
1
2
2
Fig. 1. Crystal structure and coordination polyhedron geometry of Mn(III) in 1.