Synthesis, Crystal Structures, and Catalytic Oxidation of Olefins of Novel Oxomolybdenum(VI) Clusters

Article abstract of DOI:10.1134/S1070328419060058

Abstract: Two Mo(VI) clusters, (H₂L)₃[Mo₇O₁₂(μ₂-O)₈(μ₃-O)₄] · 3H₂O (I) and (H₂L)₂[Mo₈O₁₄(μ₂-O)_6<

Full text of DOI:10.1134/S1070328419060058

ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2019, Vol. 45, No. 6, pp. 457–466. © Pleiades Publishing, Ltd., 2019.
Synthesis, Crystal Structures, and Catalytic Oxidation
of Olefins of Novel Oxomolybdenum(VI) Clusters
D. L. Penga, b,
*
aKey Laboratory of Surface and Interface Science of Henan Province, School of Material and Chemical Engineering,
Zhengzhou University of Light Industry, Zhengzhou, 450001 P.R. China
bHenan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration,
Zhengzhou University of Light Industry, Zhengzhou, 450001 P.R. China
*e-mail: pengdonglai2015@sina.com
Received May 30, 2018; revised December 20, 2018; accepted December 26, 2018
Abstract—Two Mo(VI) clusters, (H2L)3[Mo7O12(μ2-O)8(μ3-O)4] · 3H2O (I) and (H2L)2[Mo8O14(μ2-O)6(μ3-
O)4(μ5-O)2] · 4DMF (II), derived from MoO2(Acac)2 and N-methylethane-1,2-diamine (L) in water and
DMF, respectively, are reported. The complexes were characterized by single crystal structure analysis (CIF
files CCDC nos. 1846032 (I) and 1443681 (II)). Compound I contains a seven nuclear molybdenum(VI)
complex anion, three H2L cations and three water molecules. Compound II contains an eight nuclear molyb-
denum(VI) complex anion, two H2L cations and four DMF molecules. All Mo atoms are in octahedral coor-
dination. Complex I crystallized as monoclinic space group P21/n with unit cell dimensions a = 12.3005(12),
b = 17.3944(17), c = 15.9446(16) Å, β = 93.862(2)°, V = 3403.8(6) Å3, Z = 4, R1 = 0.0795, wR2 = 0.1677.
Complex II crystallized as monoclinic space group P21/n with unit cell dimensions a = 11.1465(13), b =
16.460(2), c = 12.7942(16), β = 97.368(2)°, V = 2328.0(5) Å3, Z = 2, R1 = 0.0362, wR2 = 0.0754. The com-
plexes were tested as catalyst for the oxidation of olefins and showed effective activity.
Keywods: oxomolybdenum(VI) cluster, N-methylethane-1,2-diamine, catalysis, oxidation, olefins
DOI: 10.1134/S1070328419060058
INTRODUCTION
(H2L)2[Mo8O14(μ2-O)6(μ3-O)4(μ5-O)2] · 4DMF (II),
derived from MoO2(Acac)2 and N-methylethane-1,2-
diamine (L), are reported.
Molybdenum is an essential metal that is capable of
forming metal complexes with various ligands [1–5].
Molybdenum is not only much less toxic than many
other metals of industrial importance but it is also an
essential constituent of certain enzymes that catalyze
reduction of molecular nitrogen and nitrate in plants
and oxidation (hydroxylation) of xanthine and other
purines and aldehydes in animals [6]. Epoxides are
very important chemicals for manufacturing a range of
important commercial products such as pharmaceuti-
cals and polymers. Many transition metal compounds
have been reported for oxidation of olefins [7–13].
Molybdenum compounds are known for considerable
use in organic chemistry, in particular for the various
oxidations of organic compounds [2, 4, 14]. Oxido-
peroxido molybdenum compounds have been inten-
sively investigated as oxidation catalysts for variety of
organic substrates, particularly for sulfoxidation and
epoxidation of olefins [15–18]. In order to further
study the catalytic potentiality of the molybdenum
compounds, in this paper, the synthesis, crystal struc-
tures and catalytic activity of Mo(VI) clusters,
EXPERIMENTAL
Materials and methods. All the reagents and sol-
vents used in the synthesis were procured commer-
cially and used without subsequent purification. The
starting material, bis(acetylacetonato) dioxomolybde-
num(VI), [MoO2(Acac)2] was prepared as described
in the literature [19]. Microanalyses (C, H, and N)
were performed using a Perkin-Elmer 2400 elemental
analyzer. Single crystal X-ray data were collected on a
Bruker SMART APEX II diffractometer.
Synthesis of I. N-Methylethane-1,2-diamine (0.074 g,
1.0 mmol) and MoO2(Acac)2 (0.328 g, 1.0 mmol) were
dissolved in 20 mL water. The mixture was stirred at
room temperature for 30 min, to give colorless solu-
tion. After leaving the solution for a few days at room
temperature, colorless prism crystals were formed.
(H2L)3[Mo7O12(μ2-O)8(μ3-O)4]
·
3H2O (I) and
457

458
PENG
Table 1. Crystallographic data and refinement parameters for compounds I, II
Value
Parameter
I
II
Formula weight
Crystal size, mm
Temperature, K
Crystal system
Space group
a, Å
b, Å
c, Å
β, deg
1338.07
0.13 × 0.12 × 0.12
298(2)
1628.20
0.20 × 0.20 × 0.19
298(2)
Monoclinic
P21/n
Monoclinic
P21/n
12.3005(12)
17.3944(17)
15.9446(16)
93.862(2)
11.1465(13)
16.460(2)
12.7942(16)
97.368(2)
V, Å3
3403.8(6)
2328.0(5)
Z
4
2
calcd, g cm–3
2.611
2.323
ρ
μ(MoKα), mm–1
2.600
2.180
F(000)
2592
19982
6339
1584
21579
5301
Number of measured reflections
Number observed reflections with I > 2σ(I)
Unique reflections
5134
4667
Refinement parameters
Number of restraints
R1, wR2 (I > 2σ(I))*
465
27
0.0795, 0.1677
0.0961, 0.1750
1.236
295
0
0.0362, 0.0754
0.0435, 0.0795
1.342
R1, wR2 (all data)*
Goodness of fit of F2
2
2
2
2 1/2
2
* R = ||F | – |F ||/|F |, wR = [w(
–
) /w( ) ]
Fo
.
Fo Fc
1
o
c
o
2
The product was filtered and washed with methanol.
The yield was 21%.
X-ray structure determination. X-ray data for the
compounds were collected on a Bruker SMART
APEXII diffractometer equipped with graphite-
monochromated MoKα radiation (λ = 0.71073 Å). A
preliminary orientation matrix and cell parameters
were determined from three sets of ω scans at different
starting angles. Data frames were obtained at scan
intervals of 0.5° with an exposure time of 10 s frame–1.
The reflection data were corrected for Lorentz and
polarization factors. Absorption corrections were car-
ried out using SADABS [20]. The structures were
solved by direct methods and refined by full-matrix
least-squares analysis using anisotropic thermal
parameters for non-H atoms with the SHELXTL pro-
gram [21]. The water H atoms were located from dif-
ference Fourier maps and refined isotropically, with
O–H and H···H distances restrained to 0.85(1) and
1.37(2) Å. The remaining H atoms were calculated at
idealized positions and refined with the riding models.
Crystallographic data for the compounds is summa-
For C9H42N6O27Mo7
Anal. calcd., %
Found, %
C, 8.08
C, 8.21
H, 3.16
H, 3.25
N, 6.28
N, 6.21
Synthesis of II. N-Methylethane-1,2-diamine
(0.074 g, 1.0 mmol) and MoO2(Acac)2 (0.328 g,
1.0 mmol) were dissolved in 20 mL DMF. The mix-
ture was stirred at room temperature for 30 min, to give
slight yellow solution. After leaving the solution for a
few days at room temperature, yellow block crystals
were formed. The product was filtered and washed
with methanol. The yield was 15%.
For C18H52N8O30Mo8
Anal. calcd., %
Found, %
C, 13.28
C, 13.15
H, 3.22
H, 3.31
N, 6.88
N, 6.79
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SYNTHESIS, CRYSTAL STRUCTURES, AND CATALYTIC OXIDATION
Table 2. Selected bond lengths (Å) for compounds I, II*
Bond d, Å Bond d, Å
459
Bond
d, Å
Bond
d, Å
I
Mo(1)–O(22) 1.685(10) Mo(4)–O(13) 2.134(9)
Mo(1)–O(21)
1.734(11)
1.988(11)
2.252(9)
1.727(12)
Mo(4)–O(9)
Mo(5)–O(15)
Mo(5)–O(12)
Mo(5)–O(26)
2.253(11)
1.710(12)
1.930(12)
2.570(13)
1.720(10)
2.004(9)
2.274(9)
Mo(1)–O(20) 1.951(10) Mo(5)–O(14) 1.690(12) Mo(1)–O(3)
Mo(1)–O(4) 2.161(10) Mo(5)–O(16) 1.927(9)
Mo(2)–O(2) 1.719(11) Mo(5)–O(13) 2.147(9)
Mo(1)–O(19)
Mo(2)–O(1)
Mo(2)–O(3) 1.907(11) Mo(6)–O(17) 1.716(10) Mo(2)–O(5)
Mo(2)–O(4) 2.162(9) Mo(6)–O(20) 1.946(10) Mo(2)–O(27)
Mo(3)–O(6) 1.708(11) Mo(6)–O(13) 2.143(9) Mo(3)–O(7)
1.934(13) Mo(6)–O(18)
2.428(11) Mo(6)–O(16)
1.718(12)
1.973(11)
Mo(6)–O(19)
Mo(7)–O(26)
Mo(3)–O(8) 1.901(10) Mo(7)–O(27) 1.732(11) Mo(3)–O(5)
Mo(3)–O(4) 2.109(10) Mo(7)–O(19) 1.873(10) Mo(3)–O(9)
1.749(11)
1.903(10)
2.299(10)
2.268(10) Mo(7)–O(9)
Mo(4)–O(11) 1.710(12)
Mo(4)–O(8) 1.941(11)
Mo(7)–O(13) 2.282(10) Mo(4)–O(10)
1.716(12)
2.002(11)
Mo(7)–O(4)
Mo(4)–O(12)
II
Mo(1)–O(1) 1.696(3)
Mo(1)–O(4) 1.941(3)
Mo(1)–O(5) 2.158(3)
Mo(2)–O(6) 1.701(3)
Mo(2)–O(8) 1.911(3)
Mo(2)–O(3) 2.282(3)
Mo(3)–O(9)
Mo(3)–O(8)
Mo(3)–O(4)
1.697(3)
1.896(3)
2.324(3)
Mo(1)–O(3)
Mo(1)–O(2)
Mo(1)–O(5A)
Mo(2)–O(7)
1.747(3)
1.947(3)
2.351(3)
1.709(3)
Mo(3)–O(10)
Mo(3)–O(2A)
Mo(3)–O(5A)
Mo(4)–O(11)
Mo(4)–O(4)
Mo(4)–O(2A)
1.698(3)
2.003(3)
2.336(3)
1.698(3)
1.996(3)
2.333(3)
Mo(4)–O(12) 1.695(3)
Mo(4)–O(13) 1.894(3)
Mo(2)–O(13A) 1.920(3)
Mo(2)–O(5A) 2.460(3)
Mo(4)–O(5)
2.318(3)
rized in Table 1. Selected bond lengths and angles are comparison with authentic samples. All the reactions
listed in Tables 2 and 3, respectively.
were run two times.
Supplementary material for structures has been
deposited with the Cambridge Crystallographic Data
Centre (CCDC nos. 1846032 (I) and 1443681 (II);
deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.
ac.uk).
RESULTS AND DISCUSSION
Compounds I, II were prepared in a similar proce-
dure with different solvents. Crystals of the com-
pounds are stabilized in air at room temperature, and
soluble in water, methanol, ethanol, and DMF.
Catalytic epoxidation of olefins. In a typical cata-
lytic experiment, tert-butylhydroperoxide (TBHP)
(1 mmol) was added to a solution of olefin (1 mmol),
chlorobenzene (1 mmol) as an internal standard and
the complexes (2 × 10–4 mmol) in 1,2-dichloroethane
(0.5 mL). The mixture was stirred at 80°C under air
and the course of the reaction was monitored using gas
chromatography (Agilent Technologies Instruments
6890N, equipped with a capillary column (19019J-413
HP-5, 5% Phenyl Methyl Siloxane, Capillary
60.0 m × 250 μm × 1.00 μm) and a flame ionization
detector). Assignments of products were made by
Molecular structures of the compounds I and II are
shown in Fig. 1. Compound I contains a seven nuclear
molybdenum(VI) complex anion, three H2L cations,
and three water molecules. Compound II contains an
eight nuclear molybdenum(VI) complex anion, two
H2L cations, and four DMF molecules. In the anionic
moiety of compound I, there are eight μ2-O bridging
groups, four μ3-O bridging groups, and twelve termi-
nal oxido groups. In the anionic moiety of compound
II, there are six μ2-O bridging groups, four μ3-O bridg-
ing groups, two μ5-O bridging groups, and fourteen
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460
PENG
Table 3. Selected bond angles (deg) for compounds I, II*
Angle
ω, deg
Angle
ω, deg
Angle
ω, deg
I
O(22)Mo(1)O(21)
O(21)Mo(1)O(20)
O(21)Mo(1)O(3)
104.4(6)
100.7(5)
92.2(5)
O(14)Mo(5)O(26)
O(16)Mo(5)O(26)
O(13)Mo(5)O(26)
177.1(5)
80.2(4)
70.2(3)
O(8)Mo(3)O(5)
O(7)Mo(3)O(4)
O(5)Mo(3)O(4)
155.6(4)
156.3(5)
74.2(4)
O(22)Mo(1)O(4)
O(20)Mo(1)O(4)
O(22)Mo(1)O(19)
O(20)Mo(1)O(19)
O(4)Mo(1)O(19)
O(2)Mo(2)O(3)
O(2)Mo(2)O(5)
O(3)Mo(2)O(5)
O(1)Mo(2)O(4)
O(5)Mo(2)O(4)
O(1)Mo(2)O(27)
O(5)Mo(2)O(27)
O(6)Mo(3)O(7)
O(7)Mo(3)O(8)
O(7)Mo(3)O(5)
O(6)Mo(3)O(4)
O(8)Mo(3)O(4)
O(6)Mo(3)O(9)
O(8)Mo(3)O(9)
O(4)Mo(3)O(9)
O(11)Mo(4)O(8)
O(11)Mo(4)O(12)
O(8)Mo(4)O(12)
O(10)Mo(4)O(13)
O(12)Mo(4)O(13)
O(10)Mo(4)O(9)
96.0(5)
87.7(4)
166.2(5)
74.5(4)
72.5(4)
101.6(5)
102.7(6)
147.2(4)
105.9(5)
73.7(4)
176.3(5)
81.4(4)
103.4(6)
99.7(5)
91.4(5)
97.6(5)
87.7(4)
167.9(5)
73.8(4)
73.1(4)
98.2(5)
101.6(5)
154.0(4)
156.8(5)
72.5(4)
90.2(5)
O(17)Mo(6)O(20)
O(17)Mo(6)O(16)
O(20)Mo(6)O(16)
O(18)Mo(6)O(13)
O(16)Mo(6)O(13)
O(18)Mo(6)O(19)
O(16)Mo(6)O(19)
O(27)Mo(7)O(26)
O(26)Mo(7)O(19)
O(26)Mo(7)O(9)
O(27)Mo(7)O(13)
O(19)Mo(7)O(13)
O(27)Mo(7)O(4)
O(19)Mo(7)O(4)
O(13)Mo(7)O(4)
O(22)Mo(1)O(20)
O(22)Mo(1)O(3)
O(20)Mo(1)O(3)
O(21)Mo(1)O(4)
O(3)Mo(1)O(4)
O(21)Mo(1)O(19)
O(3)Mo(1)O(19)
O(2)Mo(2)O(1)
O(1)Mo(2)O(3)
O(1)Mo(2)O(5)
O(2)Mo(2)O(4)
100.0(5)
92.6(4)
155.9(4)
95.9(5)
73.2(4)
165.8(5)
85.9(4)
104.9(5)
101.6(5)
102.3(5)
170.8(4)
76.9(4)
82.0(4)
76.7(4)
88.8(3)
98.0(5)
99.5(5)
154.9(4)
156.4(5)
72.7(4)
88.5(4)
84.5(4)
104.3(6)
99.1(6)
95.8(6)
149.7(5)
O(7)Mo(3)O(9)
87.3(5)
85.2(4)
104.3(6)
101.1(6)
90.3(5)
94.5(5)
89.3(4)
164.5(5)
73.5(4)
72.8(4)
99.3(5)
99.0(6)
146.7(4)
147.5(5)
73.5(4)
77.3(5)
80.1(4)
104.7(5)
98.4(5)
98.2(5)
156.6(4)
87.8(4)
88.6(4)
74.1(4)
72.1(4)
101.5(5)
O(5)Mo(3)O(9)
O(11)Mo(4)O(10)
O(10)Mo(4)O(8)
O(10)Mo(4)O(12)
O(11)Mo(4)O(13)
O(8)Mo(4)O(13)
O(11)Mo(4)O(9)
O(8)Mo(4)O(9)
O(13)Mo(4)O(9)
O(14)Mo(5)O(16)
O(14)Mo(5)O(12)
O(16)Mo(5)O(12)
O(1)5Mo(5)O(13)
O(1)2Mo(5)O(13)
O(1)5Mo(5)O(26)
O(1)2Mo(5)O(26)
O(17)Mo(6)O(18)
O(18)Mo(6)O(20)
O(18)Mo(6)O(16)
O(17)Mo(6)O(13)
O(20)Mo(6)O(13)
O(17)Mo(6)O(19)
O(20)Mo(6)O(19)
O(13)Mo(6)O(19)
O(27)Mo(7)O(19)
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SYNTHESIS, CRYSTAL STRUCTURES, AND CATALYTIC OXIDATION
461
Table 3. (Contd.)
Angle
ω, deg
Angle
ω, deg
Angle
ω, deg
O(12)Mo(4)O(9)
O(14)Mo(5)O(15)
O(15)Mo(5)O(16)
O(15)Mo(5)O(12)
O(14)Mo(5)O(13)
O(16)Mo(5)O(13)
83.3(4)
105.6(7)
100.3(5)
101.3(5)
106.9(5)
74.6(4)
O(3)Mo(2)O(4)
O(2)Mo(2)O(27)
O(3)Mo(2)O(27)
O(4)Mo(2)O(27)
O(6)Mo(3)O(8)
O(6)Mo(3)O(5)
74.2(4)
78.6(5)
82.3(4)
71.1(4)
98.5(5)
99.9(5)
O(27)Mo(7)O(9)
O(19)Mo(7)O(9)
O(26)Mo(7)O(13)
O(9)Mo(7)O(13)
O(26)Mo(7)O(4)
O(9)Mo(7)O(4)
100.5(5)
141.9(4)
84.4(5)
76.5(4)
173.2(5)
76.1(4)
II
O(1)Mo(1)O(3)
O(3)Mo(1)O(4)
O(3)Mo(1)O(2)
O(1)Mo(1)O(5)
O(4)Mo(1)O(5)
O(1)Mo(1)O(5A)
O(4)Mo(1)O(5A)
O(5)Mo(1)O(5A)
O(6)Mo(2)O(8)
O(6)Mo(2)O(13A)
O(8)Mo(2)O(13A)
O(7)Mo(2)O(3)
O(13)Mo(2)O(3A)
O(7)Mo(2)O(5A)
O(3)Mo(2)O(5A)
O(9)Mo(3)O(8)
O(9)Mo(3)O(2A)
O(8)Mo(3)O(2A)
O(10)Mo(3)O(4)
O(2)Mo(3)O(4A)
104.31(15)
97.89(14)
96.33(14)
98.59(13)
78.10(11)
174.25(13)
77.56(11)
75.70(12)
103.17(16)
102.36(16)
144.58(13)
164.34(13)
77.20(12)
94.76(13)
69.61(10)
101.27(15)
96.48(14)
146.37(12)
90.09(14)
71.52(11)
O(10)Mo(3)O(5A)
O(4)Mo(3)O(5A)
O(12)Mo(4)O(13)
O(12)Mo(4)O(4)
O(13)Mo(4)O(4)
O(11)Mo(4)O(5)
O(4)Mo(4)O(5)
O(11)Mo(4)O(2A)
O(4)Mo(4)O(2A)
O(1)Mo(1)O(4)
O(1)Mo(1)O(2)
O(4)Mo(1)O(2)
O(3)Mo(1)O(5)
O(2)Mo(1)O(5)
O(3)Mo(1)O(5A)
O(2)Mo(1)O(5A)
O(6)Mo(2)O(7)
O(7)Mo(2)O(8)
O(7)Mo(2)O(13A)
161.11(14)
71.03(10)
101.18(15)
96.88(15)
146.63(12)
159.84(15)
73.30(11)
88.07(14)
71.42(11)
102.12(14)
100.24(14)
149.54(12)
157.07(13)
78.33(11)
81.38(12)
78.13(11)
105.29(16)
98.58(15)
97.90(15)
O(6)Mo(2)O(3)
O(8)Mo(2)O(3)
O(6)Mo(2)O(5A)
O(8)Mo(2)O(5A)
O(9)Mo(3)O(10)
O(10)Mo(3)O(8)
O(10)Mo(3)O(2A)
O(9)Mo(3)O(4)
O(8)Mo(3)O(4)
O(9)Mo(3)O(5A)
O(8)Mo(3)O(5A)
O(12)Mo(4)O(11)
O(11)Mo(4)O(13)
O(11)Mo(4)O(4)
O(12)Mo(4)O(5)
O(13)Mo(4)O(5)
O(12)Mo(4)O(2A)
O(13)Mo(4)O(2A)
O(5)Mo(4)O(2A)
90.32(14)
78.51(13)
159.93(14)
74.04(11)
104.83(17)
101.38(16)
101.34(15)
162.67(13)
83.99(12)
93.82(14)
77.40(12)
105.57(17)
100.37(16)
101.48(15)
94.46(14)
77.50(12)
163.82(14)
84.47(12)
71.78(10)
* Symmetry code for A: 1 – x, 1 – y, 1 – z.
terminal oxido groups. Each Mo center is coordinated the highest yields and the catalytic activity is the best
by six O atoms, forming an octahedral geometry. The
Mo–O bonds in both compounds are similar to each
other and comparable to those observed in similar
oxomolybdenum clusters [22, 23].
when 1,2-dichloroethane was used as the solvent. At
80°C with 1,2-dichloroethane, a turnover number
(TON) of 5530 with the compound can be achieved.
So, 1,2-dichloroethane can be used as solvent in the
catalyst experiment.
In the crystal structure of both compounds, the
molybdenum clusters are linked by H2L cations and
water or DMF molecules through hydrogen bonds
(Table 4), to form three-dimensional network (Fig. 2).
The catalytic epoxidation of some olefins using the
compounds as catalysts is summarized in Table 6. In
general, both compounds show similar catalytic prop-
erties. It is clear that the epoxide yields and selectivity
are good for cyclohexene (entries 1 and 2). However,
the catalytic property decreased for styrene, p-fluoro-
styrene, p-chlorostyrene, and p-bromostyrene. The
electronic effects may play key roles in the catalytic
processes. The catalytic property of p-fluorostyrene,
p-chlorostyrene and p-bromostyrene is better than
Considering the structures of two compounds are
similar, the present work used compound I as catalyst
to explore suitable experimental conditions. The cata-
lytic property of compound I was first studied in the
homogeneous epoxidation of cyclohexene, used as a
model substrate, and TBHP as the oxygen donor. The
influence of several solvents was evaluated (Table 5). It
is clear that toluene and 1,2-dichloroethane produce styrene (entries 3–10). The complexes were highly
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 6 2019

462
PENG
(a)
O(15)
O(14)
Mo(5)
O(12)
O(16)
O(26)
O(18)
Mo(6)
O(11)
O(13)
O(9)
O(10)
O(17)
Mo(4)
O(8)
O(19)
Mo(7)
O(27)
O(4)
Mo(1)
O(20)
O(2)
O(7)
O(21)
O(3)
Mo(3)
N(4)
C(9)
O(5)
Mo(2)
O(1)
C(8)
N(6)
O(22)
O(23)
O(6)
N(3)
C(6)
N(5)
C(7)
O(24)
O(25)
C(5)
C(4)
N(2)
C(1)
C(2)
N(1)
C(3)
(b)
O(11)
O(10)
O(12)
C(20)
O(13)
Mo(4)
C(24)
Mo(3)
O(4)
N(3)
C(21)
O(14)
O(9)
O(5)
O(8)
O(1)
O(3)
Mo(2)
O(6)
Mo(1)
C(23)
N(4)
O(7)
O(2)
N(1)
C(17)
C(15)
C(18)
C(19)
C(22)
O(15)
N(2)
Fig. 1. Molecular structure of I (a) and II (b) with atom labeling scheme and 30% probability thermal ellipsoids for all non-hydro-
gen atoms.
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SYNTHESIS, CRYSTAL STRUCTURES, AND CATALYTIC OXIDATION
Table 4. Geometric parameters of hydrogen bond for compounds I and II*
463
Distance, Å
H∙∙∙A
D–H∙∙∙A
Angle D–H∙∙∙A, deg
D–H
D∙∙∙A
I
N(1)–H(1A)∙∙∙O(2)#1
N(1)–H(1A)∙∙∙O(27)#1
N(1)–H(1B)∙∙∙O(20)#2
N(2)–H(2B)∙∙∙O(11)#2
N(2)–H(2A)∙∙∙O(6)#3
155(5)
133(5)
169(5)
156(5)
136(5)
141(5)
0.90
0.90
0.90
0.89
0.89
0.89
0.89
0.90
0.90
0.90
0.90
0.90
0.89
0.89
0.89
0.89
0.90
0.90
0.90
0.89
0.89
0.89
2.21
2.31
1.94
2.02
2.23
2.52
1.95
2.04
2.50
2.28
2.32
2.55
2.02
1.87
2.22
2.40
2.31
2.56
2.60
2.03
2.61
2.22
3.050(18)
2.992(16)
2.826(15)
2.857(18)
2.937(19)
3.26(2)
N(2)–H(2A)∙∙∙O(7)#3
N(2)–H(2C)∙∙∙O(25)
2.74(3)
146(6)
138(5)
N(3)–H(3D)∙∙∙O(12)#4
N(3)–H(3D)∙∙∙O(10)#4
N(3)–H(3E)∙∙∙O(21)#5
N(3)–H(3E)∙∙∙O(17)#5
N(3)–H(3E)∙∙∙O(19)#5
N(4)–H(4A)∙∙∙O(16)#5
N(4)–H(4B)∙∙∙O(24)#6
N(4)–H(4C)∙∙·O(1)#7
N(4)–H(4C)∙∙∙O(5)#7
N(5)–H(5C)∙∙∙O(5)#8
N(5)–H(5C)∙∙∙O(7)#8
N(5)–H(5D)∙∙∙O(9)#8
N(6)–H(6D)∙∙∙O(3)#3
N(6)–H(6D)∙∙∙O(21)#3
N(6)–H(6F)∙∙∙O(23)#5
2.771(18)
3.32(2)
151(5)
137(5)
117(6)
150(5)
167(5)
174(5)
146(5)
140(5)
115(6)
123(6)
151(6)
145(5)
138(5)
154(5)
155(5)
3.004(17)
2.852(18)
3.355(17)
2.898(18)
2.75(2)
3.00(2)
3.127(18)
2.81(4)
3.14(4)
3.42(4)
2.81(3)
3.32(3)
3.05(4)
N(6)–H(6E)∙∙∙O(7)#8
O(24)–H(24A)∙∙∙O(1)
O(23)–H(23A)∙∙∙O(22)
0.89
2.14
2.97(3)
3.22(2)
2.84(2)
0.85(1)
0.85(1)
2.60(13)
2.03(8)
130(14)
160(21)
II
N(1)–H(1A)∙∙∙O(15)#9
N(1)–H(1B)∙∙∙O(14)
N(1)–H(1B)∙∙∙O(3)
N(2)–H(2A)∙∙∙O(15)#9
N(2)–H(2B)∙∙∙O(1)#7
154(5)
0.90
0.90
0.90
0.89
1.95
1.84
2.51
2.07
2.788(6)
2.681(6)
3.015(5)
2.859(6)
154(5)
116(5)
147(5)
162(5)
168(5)
#6
0.89
0.89
2.04
2.07
2.893(5)
2.943(5)
N(2)–H(2C)∙∙∙O(7)#6
#1
#2
#3
#4
#5
* Symmetry codes: 3/2 – x, –1/2 + y, 3/2 – z; 1 + x, y, z; 1 – x, 1 – y, 1 – z; 3/2 + x, 3/2 – y, –1/2 + z; x, y, –1 + z; 1/2 – x,
#7
#8
#9
1/2 + y, 1/2 – z; –1/2 + x, 3/2 – y, –1/2 + z; 1/2 – x, –1/2 + y, 1/2-z; 1/2 – x, 1/2 + y, 3/2 – z.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 45 No. 6 2019

464
PENG
(a)
x
z
0
y
(b)
x
0
z
y
Fig. 2. Molacular packing diagrams of I viewed along the x axis (a) and II viewed along the x axis (b). Hydrogen bonds are shown
as dashed lines.
Table 5. The solvent effects on the catalytic epoxidation of cyclohexene with TBHP using I as the catalyst*
Entry
Solvent
Conversion
Time, h
TON**
1
2
3
4
5
6
MeOH
EtOH
78
82
1
3125
3331
3553
3446
4572
5530
1
MeCN
90
1
Cyclohexane
Toluene
87
1
1
96
1,2-Dichloroethane
100
30 min
* The molar ratio for the compound : cyclohexene : TBHP is 1 : 5000 : 5000. The reactions were carried out at 80°C.
** TON = (mmol of product)/mmol of catalyst.
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SYNTHESIS, CRYSTAL STRUCTURES, AND CATALYTIC OXIDATION
Table 6. Catalytic oxidation results*
465
Entry
Substrate
Product
Compound Conversion, % Selectivity, %
TON
5700
5560
1239
1
2
3
I
II
I
100
100
64
100
100
59
O
O
4
II
68
52
1356
O
5
6
I
II
I
82
80
77
73
72
78
69
64
58
61
65
62
1780
1655
1381
1527
2120
1897
F
F
Cl
Br
O
7
Cl
Br
8
II
I
O
9
10
II
* The molar ratio for the catalyst : olefin : TBHP is 1 : 5000 : 5000. The reactions were carried out at 80°C for 1 h.
4. Chatterjee, I., Chowdhury, N.S., Ghosh, P., et al.,
selective for the epoxide for cyclohexene, but lower for
various styrenes with benzaldehyde and acetophenone
derivatives as side products.
Inorg. Chem., 2015, vol. 54, no. 11, p. 5257.
5. Sieh, D., Lacy, D.C., Peters, J.C., et al., Chem. Eur. J.,
2015, vol. 21, no. 23, p. 8497.
Thus two novel Mo(VI) clusters have been synthe-
sized and characterized by single crystal X-ray struc-
ture analysis. The Mo atoms are in octahedral coordi-
nation. The compounds were employed as catalyst for
the epoxidation of various olefins with tert-butylhy-
droperoxide in dichloroethane. The compounds can
catalyze cyclohexene to its epoxide with TBHP as the
oxidant, with high yield and selectivity.
6. Rayati, S., Rafiee, N., and Wojtczak, A., Inorg. Chim.
Acta, 2012, vol. 386, p. 27.
7. Alemohammad, T., Safari, N., Rayati, S., et al., Inorg.
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9. Bagherzadeh, M., Ghanbarpour, A., and Khavasi,
H.R., Catal. Commun., 2015, vol. 65, p. 72.
10. Pranckevicius, C., Fan, L., and Stephan, D.W., J. Am.
Chem. Soc., 2015, vol. 137, no. 16, p. 5582.
11. Safin, D.A., Pialat, A., Korobkov, I., et al., Chem. Eur.
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FUNDING
The author acknowledges the Zhengzhou Univer-
sity of Light Industry for supporting this work.
12. Bagh, B., McKinty, A.M., Lough, A.J., et al., Dalton
Trans., 2015, vol. 44, no. 6, p. 2712.
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