2
H L Schiff bases were prepared according to the literature method [14, 15]. Elemental analyses were carried out using
3
a Perkin–Elmer 2400 II elemental analyzer. Infrared spectra were recorded on a Perkin–Elmer FT-IR spectrophotometer with
a KBr disc. GC analyses were carried out using a Shimadzu GC-2014C gas chromatograph. The X-ray diffraction was carried
out on a Bruker SMART 1000 CCD area diffractometer at 298(2) K.
1
Synthesis of 1. H L (3.36 g, 0.01 mol) and manganese perchlorate (3.62 g, 0.01 mol) were dissolved and stirred in
2
methanol (50 ml). The mixture was stirred at room temperature for 1 h and filtered. The filtrate was kept still at room
temperature for several days, to give deep brown block-like single crystals. Yield: 45%. Anal. Calcd. for C H Cl MnN O
8
17 18
3
2
–1
(%): C 37.8, H 3.4, N 5.2. Found (%): C 37.6, H 3.3, N 5.3. IR (KBr, cm ): 3423 (m, O–H), 3020-2826 (w, C–H of aliphatic
and aromatic), 1616 (s, C=N), 1560-1500 (s, C=C), 1215 (m, C–O), 1103 (s, Cl–O).
2
Synthesis of 2. H L (6.62 g, 0.01 mol) and manganese perchlorate (3.62 g, 0.01 mol) were dissolved and stirred in
3
methanol (50 ml). The mixture was stirred at room temperature for 1 h and filtered. The filtrate was kept still at room
temperature for several days, to give deep brown block-like single crystals. Yield: 33%. Anal. Calcd. for C H Cl MnN O
3
27 21
6
4
–1
(%): C 45.2, H 3.0, N 7.8. Found (%): C 45.4, H 2.8, N 7.8. IR (KBr, cm ): 3013-2830 (w, C–H of aliphatic and aromatic),
1613 (s, C=N), 1560-1500 (s, C=C), 1218 (m, C–O).
X-ray crystallography. Single crystals of the complexes were mounted on the top of a glass fiber. Graphite
monochromatized MoK radiation (λ = 0.71073 Å) and the ω scanning technique were used to collect the diffraction data.
α
Absorption correction was applied with SADABS [16]. The structures of the complexes were solved by a direct method and
refined by a full matrix least squares technique using SHELXTL [17]. Anisotropic thermal parameters were applied to all
non-hydrogen atoms. The hydrogen atoms of the water and methanol molecules were located from electron density maps,
with O–H and H⋯H distances restrained to 0.85(1) Å and 1.37(2) Å, respectively. The other hydrogen atoms were generated
geometrically. The perchlorate anions in complex 1 are disordered, with occupancies of 0.323(2) and 0.677(2) for the Cl1–
O9–O10–O11–O12 group, and 0.766(2) and 0.234(2) for the Cl2–O13–O14–O15–O16 group. The crystallographic data and
details of the data collection and refinement for the complex are listed in Table 1. Selected bond lengths and angles are given
in Table 2. Hydrogen bonding information is given in Table 3. Crystallographic data for the complexes have been deposited
with the Cambridge Crystallographic Data Centre (CCDC 1008303 and 1008304).
Catalytic epoxidation of olefins. To a solution of olefins (0.28 mmol), NaHCO (0.11 mmol) and catalyst
3
−4
(9.4×10 mmol) in MeCN (0.5 ml) H O (1.1 mmol, 30% H O solution) was added as an oxidant. After the reaction was
2
2
2
over, for the products analysis the solution was subjected to multiple ether extraction, and the extract was also concentrated
3
down to 0.5 cm by distillation in a rotary evaporator at room temperature; then a sample (2 μL) was taken from the solution
and analyzed by GC. The retention times of the peaks were compared with those of the commercial standards, and
chlorobenzene was used as the internal standard for the GC yield calculation.
RESULTS AND DISCUSSION
Synthesis. The two complexes were readily prepared by the reaction of equimolar quantities of the Schiff base
ligands with manganese perchlorate in methanol. It should be noted that even though no problem occurred, perchlorate salts
are potentially explosive. Only small quantities of such chemicals should be handled and with great care. Elemental analyses
of the complex are in good agreement with the expected values.
–1
Infrared spectra of the complexes. The medium and broad absorption centered at 3423 cm for 1 can be assigned
–1
to the O–H stretching vibrations of water and methanol ligands. Weak absorptions in the 3010-2820 cm region result from
–1 –1
C–H vibrations of the aliphatic and aromatic groups. Intense absorptions at 1616 cm for 1 and 1613 cm for 2 can be
–1
assigned to the vibration of C=N groups. The intense absorption indicative of the perchlorate anion is observed at 1103 cm .
Structure description of 1. The molecular structure of complex 1 is shown in Fig. 1. The asymmetric unit of the
complex contains two mononuclear manganese(III) complex cations and two perchlorate anions. The Mn atoms in the
complex cations are in the octahedral coordination, with two imino N and two phenolate O atoms defining the equatorial
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