168
M. Bagherzadeh et al. / Polyhedron 69 (2014) 167–173
Table 1
2. Experimental
Crystal data and details of the structure determination for [Mn3(BDC)3(DMF)4]n.
2.1. Materials and instruments
Coordination polymer
[Mn3(BDC)3(DMF)4]n
Empirical formula
Formula weight
Color and habit
Crystal system
space group
Crystal dimensions (mm)
Unit cell parameters
a (Å)
C36H40Mn3N4O16
945.98
colorless, prism
Since all the reagents and solvents for the synthesis and analysis
were commercially available, they were used as received without
further purification. The CHN elemental analysis of the compound
was obtained from a Carlo ERBA Model EA 1108 analyzer. The
FT-IR spectrum was obtained by utilizing a Unicam Matson 1000
FT-IR spectrophotometer using KBr disks at room temperature.
Thermogravimetric analysis was performed on a Perkin Elmer
TGA7 analyzer in an N2 atmosphere with a heating rate of
5 °C minꢀ1. XRD patterns were recorded on a Rigaku D-max C III,
triclinic
ꢀ
P1
0.16 ꢁ 0.20 ꢁ 0.56
9.9420(3)
12.7869(4)
16.6357(5)
74.479(2)
88.985(2)
87.228(32)
2035.3(1)
2
b (Å)
c (Å)
a
(°)
b (°)
X-ray diffractometer using Ni-filtered Cu Ka radiation. Inductively
c
(°)
V (Å3)
coupled plasma (ICP) was performed by an ICP-MS HP 4500. The
products of the olefin oxidation reactions were determined and
analyzed by an HP Agilent 6890 gas chromatograph equipped with
Z
Dcalc (g cmꢀ3
)
1.549
0.992
l
(mmꢀ1
)
an HP-5 capillary column (phenylmethylsiloxane 30 m ꢁ 320
l
m ꢁ
h (°)
4.21–30.00
ꢀ13, 13; ꢀ17, 17; ꢀ23, 23
x
974
21491
11829
8450
551
0.0650, 0.0416
0.25 m) and a flame-ionization detector.
l
h, k, l range
Scan type
F(000)
No. reflections collected
No. independent reflections
No. observed reflections, I > 2
No. refined parameters
2.2. Synthesis of [Mn3(BDC)3(DMF)4]n
r
(I)
A solution of 1,4-benzenedicarboxylic acid (H2BDC) (166 mg,
1 mmol) in 5 mL DMF was added to a DMF solution (5 mL) of
MnCl2ꢂ6H2O (239 mg, 1 mmol) in a small sample tube. The solution
was heated for 48 h at 80 °C without any stirring or shaking, and
then the temperature was gradually decreased to 60 °C (2 °C/hour).
After 2 days, white crystals of [Mn3(BDC)3(DMF)4]n (89% yield
based on H2BDC) were collected and removed from the vial. The
crystals were washed with DMF (3 mL, 2 times) and dried in air
to yield the pure product. Anal. Calc. for C36H40Mn3N4O16: C,
45.54; H, 4.25; N, 5.90. Found: C, 45.67; H, 4.01; N, 5.87%. FT-IR
(KBr 4000–400 cmꢀ1): 3471 (br), 3422 (br), 2936 (w), 2372 (w),
1643 (s), 1615 (s), 1555 (m), 1381 (s), 1104 (m), 886 (w), 818
(m), 750 (s), 625 (m), 516 (m).
Ra, wRb[I > 2
r(I)]
R, wR (all data)
0.1175, 0.1118
0.0664, 0.000
1.023
0.566, –0.309
0.001
g1, g2 in wc
Goodness of fit on F2, Sd
Max., min. electron density (e Åꢀ3
)
Maximum
D/r
Range of transmission factors min, max
Extinction coefficient
0.633, 0.865
none
P
P
a
b
c
R ¼ jjFoj ꢀ jFcjj= jFoj.
P
P
2
2 1=2
wR ¼ ½ ðF2o ꢀ Fc2Þ = wðF2oÞ ꢃ
.
2
w ¼ 1=½r2ðFo2Þ þ ½ðg1PÞ þ g2Pꢃꢃ where P ¼ ðFo2 þ 2F2c Þ=3.
P
2
1=2
S ¼ ½wðF2o ꢀ F2c Þ =ðNobs ꢀ NparamÞꢃ
.
d
2 mL solvent, followed by the addition of 3 mg catalyst (0.01 mmol
Mn) and then, the mixture was heated to 75 °C. The reaction was
begun with the addition of tert-butyl hydroperoxide (equimolar
with respect to substrate). The products from the reaction mixture
were analyzed by gas chromatography in the presence of chloro-
benzene as an internal standard and were identified on comparison
with known standards.
2.3. Single crystal X-ray crystallography
Selected crystal data of [Mn3(BDC)3(DMF)4]n is given in Table 1.
A single crystal of the complex was mounted in a random orienta-
tion on a glass fiber. Data collection was carried out at 296 K on an
Oxford Diffraction X Calibur four-circle kappa geometry single-
crystal diffractometer with a Sapphire 3 CCD detector, using a
graphite monochromated Mo K
a (k = 0.71073 Å) radiation, and
applying the CrysAlis Software system. The crystal-detector dis-
tance was 50 mm. Data reduction, including absorption correction,
was done by the CrysAlice RED program [34]. The structure was
solved by direct methods implemented in the SHELXS-97 program.
The coordinates and the anisotropic displacement parameters for
all non-hydrogen atoms were refined by full-matrix least-squares
methods based on F2 values using the SHELXL-97 program. All hydro-
gen atoms were placed in geometrically idealized positions and
constrained to ride on their parent C atoms with C–H = 0.93 and
0.96 Å for CH and CH3, respectively, and with Uiso (H) = k ꢁ Ueq
(C), where k = 1.2 for CH H atoms and k = 1.5 for CH3 H atoms
[35]. Graphical work was performed via OLEX2 [36]. The thermal
ellipsoids were drawn at the 50% probability level.
2.4.2. General procedure for the recyclability of the
[Mn3(BDC)3(DMF)4]n catalyst in the oxidation reaction
The recyclability of the [Mn3(BDC)3(DMF)4]n catalyst was
investigated in the oxidation reaction of styrene in the presence
Mn/TBHP in 1,2-dichloroethane at 75 °C for 9 h. After the first cat-
alytic reaction, the solid catalyst was easily isolated by centrifuge
and recovered on being washed with solvent and dried at room
temperature. Afterwards, the catalyst was used for the next run
under the same reaction conditions.
3. Result and discussion
3.1. X-ray analysis of [Mn3(BDC)3(DMF)4]n
2.4. Catalytic methods
Single-crystal X-ray structure analysis revealed that [Mn3
(BDC)3(DMF)4]n crystallizes in the triclinic P1 space group (Table 1).
ꢀ
2.4.1. General procedure for olefin oxidation
Distinct from the aforementioned reported MOF structures based
on Mn(II)-terephthalate SBUs composed of infinite Mn–O SBUs,
the structure of [Mn3(1,4-BDC)3(DMF)4]n is a 2D-periodic frame-
work composed of discrete SBUs, each of which is constructed from
MnIIO6 corner shared octahedra (Fig. 1).
For the heterogeneous oxidation of olefins, the reactions were
carried out in a magnetically stirred two necked round-bottom
flask fitted with a condenser, and placed in a temperature con-
trolled oil bath. Typically, 1 mmol of the substrate was taken in