Synthesis, crystal structures and catalytic activity of oxidovanadium(V) complexes with tridentate ONO aroylhydrazone ligands

Article abstract of DOI:10.1080/24701556.2021.1897618

Two oxidovanadium(V) complexes, [VOL¹(OEt)] (1) and [V₂O₂(L²)₂(OEt)₂] (2), where L¹ and L² are the anions of 2-amino-N′-(2-hydroxybenzylidene)benzohydrazide (H₂L¹) and N′-(2-hydroxybenzylidene)-4-hydroxybenzohydrazide (H₂L²), respectively, have been synthesized and characterized by elemental analysis, infrared and electronic spectra, and ¹H NMR spectra. Structures of the complexes were further confirmed by single-crystal X-ray determination. The V atom in the mononuclear complex 1 is in square pyramidal coordination, and those in the dinuclear complex 2 are in octahedral coordination. Both aroylhydrazone ligands coordinate to the V atoms through the phenolate O, imino N, and enolate O atoms. The ethanol ligand in complex 1 is in terminal coordination mode, while that in complex 2 is in bridging coordination mode. The complexes function as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium hydrogen carbonate as a co-catalyst.

Full text of DOI:10.1080/24701556.2021.1897618

Inorganic and Nano-Metal Chemistry
ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/lsrt21
Synthesis, crystal structures and catalytic activity
of oxidovanadium(V) complexes with tridentate
ONO aroylhydrazone ligands
Min Liang, Dong-Hui Zou, Wei Chen, Wei Kan & Zhi-Ming Tian
To cite this article: Min Liang, Dong-Hui Zou, Wei Chen, Wei Kan & Zhi-Ming Tian
(2021): Synthesis, crystal structures and catalytic activity of oxidovanadium(V) complexes
with tridentate ONO aroylhydrazone ligands, Inorganic and Nano-Metal Chemistry, DOI:
10.1080/24701556.2021.1897618
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INORGANIC AND NANO-METAL CHEMISTRY
https://doi.org/10.1080/24701556.2021.1897618
Synthesis, crystal structures and catalytic activity of oxidovanadium(V)
complexes with tridentate ONO aroylhydrazone ligands
Min Lianga, Dong-Hui Zoub, Wei Chena, Wei Kana, and Zhi-Ming Tiana
b
aSchool of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar, P.R. China; College of Food and Bio-Engineering, Qiqihar
University, Qiqihar, P.R. China
ABSTRACT
ARTICLE HISTORY
Two oxidovanadium(V) complexes, [VOL1(OEt)] (1) and [V2O2(L2)2(OEt)2] (2), where L1 and L2 are
the anions of 2-amino-N0-(2-hydroxybenzylidene)benzohydrazide (H2L1) and N0-(2-hydroxybenzyli-
dene)-4-hydroxybenzohydrazide (H2L2), respectively, have been synthesized and characterized by
elemental analysis, infrared and electronic spectra, and 1H NMR spectra. Structures of the com-
plexes were further confirmed by single-crystal X-ray determination. The V atom in the mono-
nuclear complex 1 is in square pyramidal coordination, and those in the dinuclear complex 2 are
in octahedral coordination. Both aroylhydrazone ligands coordinate to the V atoms through the
phenolate O, imino N, and enolate O atoms. The ethanol ligand in complex 1 is in terminal coord-
ination mode, while that in complex 2 is in bridging coordination mode. The complexes function
as effective olefin epoxidation catalysts with hydrogen peroxide as terminal oxidant and sodium
hydrogen carbonate as a co-catalyst.
Received 4 November 2020
Accepted 1 February 2021
KEYWORDS
Aroylhydrazone; vanadium
complex; catalytic activity;
crystal structure
Introduction
carried out using a Perkin Elmer 2400 CHNS/O elemental
analyzer. FTIR spectra were recorded on a FTIR 8400-
In recent years, much attention has been focused on the devel-
opment of environmentally benign catalytic reactions with the
increasing environmental and economical concerns. The cata-
lytic epoxidation of olefins has been a subject of growing inter-
est in the production of chemicals and fine chemicals since
epoxides are key starting materials for a wide variety of prod-
ucts.[1–4] A variety of metal complexes with hydrazone ligands
have been reported to have interesting catalytic oxidation prop-
1
Shimadzu as KBr disks in the range of 400–4000 cmꢀ1. H
NMR spectra were recorded on
a Bruker AVANCE
500 MHz spectrometer. X-ray diffraction data were collected
using a Bruker Smart 1000 CCD area diffractometer.
Synthesis of 2-amino-N0-(2-
erties.[5–9] The use of vanadium complexes in oxidation and hydroxybenzylidene)benzohydrazide (H2L1)
oxotransfer catalysis has been noted.[10,11] Aroylhydrazones
An ethanolic solution (20 mL) containing 2-hydroxybenzal-
complexes are good candidates for catalytic oxidation studies
dehyde (1.0 mmol, 0.12 g) was added dropwise to an etha-
because of their stability to resist oxidation. To continue
nolic solution of 2-aminobenzohydrazide (1.0 mmol, 0.15 g)
with constant stirring. The mixture was refluxed for
30 min, then with the solvent removed by distillation. The
white precipitate was re-crystallized from ethanol and
obtained by filtration. Yield: 0.21 g, 82%. For C14H13N3O2:
anal. calcd., %: C, 65.87; H, 5.13; N, 16.46. Found, %: C,
65.73; H, 5.26; N, 16.29. FT-IR (KBr), cmꢀ1: ꢀ(OH) 3430,
ꢀ(NH) 3234, ꢀ(CH) 2830–3100, ꢀ(C¼O) 1647, ꢀ(C¼N)
1611, ꢀ(C–O) 1155. UV–Vis data in ethanol (k, nm (e,
exploring structural and catalytic property of vanadium com-
plexes with aroylhdrazones applied in oxidation catalysis and
as part of our research in the study of coordinating capabilities
of aroylhydrazones and their coordination compounds,[12–15]
we report herein the synthesis, characterization and catalytic
property of two new oxidovanadium(V) complexes
[VOL1(OEt)] (1) and [V2O2(L2)2(OEt)2] (2), where L1 and L2
are the anions of 2-amino-N0-(2-hydroxybenzylidene)benzohy-
drazide (H2L1; Scheme 1) and N0-(2-hydroxybenzylidene)-4-
hydroxybenzohydrazide (H2L2; Scheme 1), respectively.
M
ꢀ1 cmꢀ1)]: 225 (22,120), 290 (17,350), 300 (18,515), 356
(14,272). 1H NMR (500 MHz, DMSO-d6, ppm): d ¼ 11.71
(s, 1H; OH), 10.87 (s, 1H; NH), 10.56 (s, 2H; NH2), 8.63
(s, 1H; CH¼N), 7.68 (d, 1H; ArH), 7.62 (d, 1H; ArH),
7.47 (t, 1H, ArH), 7.10 (m, 2H; ArH), 7.01 (m, 2H, ArH),
Experimental
Materials and methods
All chemicals and solvents used were of analytical reagent
grade and used as received. Micro analyses for C, H, N were 6.85 (d, 1H, ArH).
CONTACT Min Liang
liangmin09@163.com
School of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar, P. R. China.
Supplemental data for this article can be accessed at publisher’s website
ß 2021 Taylor & Francis Group, LLC

2
M. LIANG ET AL.
Scheme 1. The aroylhydrazones.
Synthesis of N0-(2-hydroxybenzylidene)-4-
hydroxybenzohydrazide (H2L2)
anal. calcd., %: C, 52.47; H, 4.13; N, 7.65. Found, %: C, 52.28;
H, 4.32; N, 7.53. FT-IR (KBr), cmꢀ1: ꢀ(OH) 3389, ꢀ(C¼N)
1612, ꢀ(C–O) 1162. UV–Vis data in ethanol (k, nm (e,
An ethanolic solution (20 mL) containing 2-hydroxybenzal-
dehyde (1.0 mmol, 0.12 g) was added dropwise to an etha-
nolic solution of 4-hydroxybenzohydrazide (1.0 mmol,
0.15 g) with constant stirring. The mixture was refluxed for
30 min, then with the solvent removed by distillation. The
white precipitate was recrystallized from ethanol and
obtained by filtration. Yield: 0.23 g, 90%. For C14H12N2O3:
anal. calcd., %: C, 65.62; H, 4.72; N, 10.93. Found, %: C,
65.45; H, 4.63; N, 11.10. FTIR (KBr), cmꢀ1: ꢀ(OH) 3542,
3434, ꢀ(NH) 3216, ꢀ(CH) 2830–3090, ꢀ(C¼O) 1650,
ꢀ(C¼N) 1610, ꢀ(C–O) 1160. UV–Vis data in ethanol (k, nm
(e, Mꢀ1 cmꢀ1)]: 213 (18,720), 255 (13,230), 302 (18,153), 328
M
ꢀ1 cmꢀ1)]: 240 (20,320), 334 (7,180), 515 (3,120).
X-ray structure determination
The crystals of the complexes were measured on a Bruker
SMART 1000 CCD area diffractometer using Mo Ka radi-
ation (k ¼ 0.71073 Å) and a graphite monochromator at
25 ꢁC. Unit cell and reflection data were obtained by the
standard method and are summarized in Table 1.[16] The
structures of both complexes were solved, refined, and pre-
pared for publication using the SHEXTL package (structure
solution refinements and molecular graphics).[17] The struc-
tures were solved using direct method and refined on F2
using full-matrix least-squares techniques with anisotropic
displacement factors for all nonhydrogen atoms. The amino
and ethanol H atoms were located from difference Fourier
maps and refined isotropically, with N–H, O–H, and HꢂꢂꢂH
distances restrained to 0.90(1), 0.85(1), and 1.43(2) Å,
respectively. Positions of the remaining hydrogen atoms
were calculated from the geometry of the molecular skeleton
and their thermal displacement parameters were refined iso-
tropically on a groupwise basis. Selected bond lengths and
angles are reported in Table 2.
1
(22,305). H NMR (500 MHz, DMSO-d6, ppm): d ¼ 12.20 (s,
1H; OH), 11.76 (s, 1H; OH), 10.95 (s, 1H; NH), 8.65 (s, 1H;
CH¼N), 7.82 (d, 2H; ArH), 7.63 (d, 1H; ArH), 7.47 (t, 1H,
ArH), 7.12 (t, 1H; ArH), 6.99 (d, 1H, ArH), 6.83 (d,
2H, ArH).
Synthesis of [VOL1(OEt)] (1)
H2L1 (0.10 mmol, 26 mg) was dissolved in ethanol (15 mL).
To the solution was added with stirring an ethanolic solu-
tion (10 mL) of VO(acac)2 (0.1 mmol, 26.5 mg). The mixture
was stirred at room temperature for 30 min to give deep
brown solution. After keeping the solution in air for a few
days, brown block-shaped single crystals, suitable for X-ray
crystal structure determination were obtained. The crystals
were isolated by filtration. Yield: 0.17 g, 47%. For
C16H16N3O4V: anal. calcd., %: C, 52.61; H, 4.41; N, 11.50.
Catalytic epoxidation of olefins
To a solution of olefins (0.28 mmol), NaHCO3 (0.11 mmol)
and catalyst (9.4 ꢃ 10ꢀ4 mmol) in MeCN (0.5 mL) was added
H2O2 (1.1 mmol, 30% H2O solution) as oxidant. After the
reaction was over, for the products analysis, the solution
was subjected to multiple ether extraction, and the extract
was also concentrated down to 0.5 mL by distillation in a
rotary evaporator at room temperature and then a sample
(2 lL) was taken from the solution and analyzed by GC.
The retention times of the peaks were compared with those
of commercial standards, and chlorobenzene was used as an
internal standard for GC yield calculation.
Found, %: C, 52.75; H, 4.53; N, 11.38. FT-IR (KBr), cmꢀ1
ꢀ(OH) 3372, ꢀ(NH) 3226, ꢀ(C¼N) 1610, ꢀ(C–O) 1155.
UV–Vis data in ethanol (k, nm (e, Mꢀ1 cmꢀ1)]: 235
(19,610), 330 (5,630), 518 (2,325).
:
Synthesis of [V2O2(L2)2(OEt)2] (2)
H2L1 (0.10mmol, 26mg) was dissolved in ethanol (15mL).
To the solution was added with stirring an ethanolic solution
(10mL) of VO(acac)2 (0.1 mmol, 26.5 mg). The mixture was
stirred at room temperature for 30min to give deep brown
solution. After keeping the solution in air for a few days,
brown block-shaped single crystals, suitable for X-ray crystal
Results and discussion
Synthesis and characterization
structure determination were obtained. The crystals were iso- The reaction of VO(acac)2 with the tridentate aroylhydra-
lated by filtration. Yield: 0.19 g, 53%. For C32H30N4O10V2: zone ligands in ethanol led to the formation of the

INORGANIC AND NANO-METAL CHEMISTRY
3
Table 1. Crystallographic data and refinement parameters for complexes 1
and 2.
vanadium complexes. The aroylhydrazone ligands contribute
to their enolic form in the complexes. The complexes are
stable at room temperature and soluble in DMSO, DMF,
ethanol, acetonitrile and less soluble in other common sol-
vents like dichloromethane, chloroform, and insoluble in
benzene, n-hexane, and CCl4.
Parameters
1
2
Mr
365.26
Brown, block
742.48
Brown, block
Crystal color, habit
Crystal size (mm3)
Crystal system
Space group
a, Å
b, Å
c, Å
0.17 ꢃ 0.13 ꢃ 0.13 0.22 ꢃ 0.20 ꢃ 0.20
Monoclinic
Pc
Orthorhombic
Pbca
11.5539(12)
14.6847(13)
19.113(2)
90
3242.8(6)
4
1.500
0.640
6.0731(13)
18.353(2)
14.658(2)
91.353(2)
1633.3(5)
4
Structure description of complex 1
ꢁ
b,
V, Å3
The molecular structure of the mononuclear vanadium com-
plex 1 is shown in Figure 1. The asymmetric unit of the
complex contains two mononuclear vanadium compounds.
The V atom in the complex is in square pyramidal coordin-
ation, with the phenolate O, imino N, and enalate O atoms
of the hydrazone ligand, and the ethanolate O atom defining
the basal plane, and with the oxo O atom locating at the
apical position. The V atoms deviate from the least-squares
plane defined by the corresponding equatorial atoms by
0.340(1) Å for V(1) and 0.324(1) Å for V(2). The coordinate
bond lengths in the complex are similar to those observed
in vanadium complexes with hydrazone ligands.[18,19] The
distortion of the square pyramidal coordination can be
observed from the coordinate bond angles, ranging from
74.7(3)ꢁ to 103.5(4)ꢁ for the perpendicular angles, and from
150.1(3)ꢁ to 160.7(3)ꢁ for the diagonal angles. The dihedral
angles between the two benzene rings of the hydrazone
ligands are 9.7(5)ꢁ for V(1) molecule and 2.1(5)ꢁ for V(2)
molecule. In the crystal structure of the complex, molecules
are linked through C(4)–H(4)ꢂꢂꢂO(7) hydrogen bonds
[C(4)–H(4) ¼ 0.93 Å, H(4)ꢂꢂꢂO(7)i ¼ 2.36 Å, C(4)ꢂꢂꢂO(7)i ¼
3.1963(7) Å, C(4)–H(4)ꢂꢂꢂO(7)i ¼ 150(5)ꢁ, symmetry code
for i: x, 1 – y, ꢀ1/2 þ z], to form dimers (Figure 2).
Z
qcalcd, g cm–3
1.485
0.633
l, mmꢀ1
F(000)
752
4671
2987
435
0.0657, 0.1436
0.1124, 0.1847
1.024
1504
3008
2165
219
0.0383, 0.0983
0.0599, 0.1148
1.029
Number of unique data
Number of observed data (I > 2r(I))
Independent parameters
R1, wR2 (I > 2r(I))
R1, wR2 (all data)
Goodness of fit on F2
Largest difference peak and hole, e Å–3 0.406 and ꢀ0.367 0.307 and ꢀ0.395
Table 2. Selected bond distances (Å) and angles (ꢁ) for complexes 1 and 2.
1
V(1)-O(1)
V(1)-O(3)
V(1)-N(1)
V(2)-O(6)
1.846(7)
1.580(7)
2.113(8)
1.929(6)
1.762(7)
102.5(4)
101.1(3)
94.2(3)
96.6(4)
82.2(3)
103.0(4)
101.9(4)
94.8(3)
V(1)-O(2)
V(1)-O(4)
V(2)-O(5)
V(2)-O(7)
1.941(6)
1.763(7)
1.834(8)
1.593(8)
2.110(8)
V(2)-O(8)
V(2)-N(3)
O(3)-V(1)-O(4)
O(4)-V(1)-O(1)
O(4)-V(1)-O(2)
O(3)-V(1)-N(1)
O(1)-V(1)-N(1)
O(7)-V(2)-O(8)
O(8)-V(2)-O(5)
O(8)-V(2)-O(6)
O(7)-V(2)-N(3)
O(5)-V(2)-N(3)
2
O(3)-V(1)-O(1)
O(3)-V(1)-O(2)
O(1)-V(1)-O(2)
O(4)-V(1)-N(1)
O(2)-V(1)-N(1)
O(7)-V(2)-O(5)
O(7)-V(2)-O(6)
O(5)-V(2)-O(6)
O(8)-V(2)-N(3)
O(6)-V(2)-N(3)
100.1(4)
101.3(3)
150.2(3)
159.7(3)
75.0(3)
101.4(4)
98.8(3)
150.1(3)
160.7(3)
74.7(3)
94.7(4)
81.7(3)
V(1)-O(1)
V(1)-O(3)
V(1)-O(4A)
1.8299(19)
1.578(2)
2.3634(18)
103.07(10)
105.99(8)
89.21(8)
96.17(10)
83.52(8)
176.71(9)
82.15(7)
85.73(7)
V(1)-O(2)
V(1)-O(4)
V(1)-N(1)
O(3)-V(1)-O(1)
O(3)-V(1)-O(2)
O(1)-V(1)-O(2)
O(4)-V(1)-N(1)
O(2)-V(1)-N(1)
O(4)-V(1)-O(4A)
O(2)-V(1)-O(4A)
1.9330(19)
1.8176(17)
2.105(2)
100.72(10)
98.65(9)
151.81(8)
156.30(8)
74.18(8)
Structure description of complex 2
O(3)-V(1)-O(4)
O(4)-V(1)-O(1)
O(4)-V(1)-O(2)
O(3)-V(1)-N(1)
O(1)-V(1)-N(1)
O(3)-V(1)-O(4A)
O(1)-V(1)-O(4A)
N(1)-V(1)-O(4A)
The molecular structure of the dinuclear vanadium com-
plex 2 is shown in Figure 3. The molecule of the complex
possesses crystallographic inversion center symmetry. The
two V atoms are bridged by deprotonated ethanol ligands,
with distance of 3.345(2) Å. The V atom in the complex is
in octahedral coordination, with the phenolate O, imino N
and enalate O atoms of the hydrazone ligands, and the
74.46(7)
79.25(7)
Symmetry code for A: 2 – x, – y, 1 – z.
Figure 1. Molecular structure of complex 1, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

4
M. LIANG ET AL.
Figure 2. Crystal packing of complex 1. Hydrogen bonds are shown as dashed lines.
atoms by 0.331(1) Å. The coordinate bond lengths in the
complex are similar to those observed in complex 1 and
other vanadium complexes with hydrazone ligands.[20,21]
The distortion of the octahedral coordination can be
observed from the coordinate bond angles, ranging from
74.18(8)ꢁ to 105.99(8)ꢁ for the perpendicular angles, and
from 151.81(8)ꢁ to 176.71(9)ꢁ for the diagonal angles. The
dihedral angle between the two benzene rings of the hydra-
zone ligand is 4.3(6)ꢁ. In the crystal structure of the com-
plex, molecules are stack along the c axis via pꢂꢂꢂp
interactions (Figure 4).
IR and UV–vis spectra of the complexes
The ꢀ(C¼N) absorptions are observed at 1610 cmꢀ1 for 1
and 1612 cmꢀ1 for 2.[22] The intense bands indicative of the
C¼O vibrations and the sharp bands indicative of the N–H
vibrations are absent in the complexes, indicating the enoli-
zation of the hydrazone ligands. The weak peaks in the low
wave numbers in the region 450–700 cmꢀ1 may be attrib-
uted to V–O and V–N bonds in the complexes. Complexes
1 and 2 exhibit typical bands at 957 and 955 cmꢀ1, respect-
ively, which are assigned to the V¼O vibrations.[23]
Figure 3. Molecular structure of complex 2, showing the atom-numbering
scheme. Displacement ellipsoids are drawn at the 30% probability level. The
symmetry code for A is 2 – x, – y, 1 – z.
ethanolate O atom defining the equatorial plane, and with
the oxo O atom and the other ethanolate O atom locating
at the axial positions. The V atoms deviate from the least-
squares plane defined by the corresponding equatorial

INORGANIC AND NANO-METAL CHEMISTRY
5
Figure 4. Crystal packing of complex 2.
Table 3. The catalytic oxidation results.a
Substrate
Product
Complex
Conversion (%)b (TON)c
1
2
100 (338)
100 (327)
1
2
100 (315)
100 (343)
1
2
98 (316)
95 (325)
1
2
95 (302)
93 (287)
aThe molar ratios for catalyst:substrate:NaHCO3:H2O2 are 1:298:117:1170. The reactions were performed in (70:30) mixture of
CH3OH/CH2Cl2 (1.2 mL) under air at room temperature. The pH of the medium is 8.4.
bThe GC conversion (%) are measured relative to the starting olefin after 75 min.
cTON ¼ (mmol of product)/mmol of catalyst.
The UV–vis spectra of the complexes were recorded in orbitals of the metal.[23] The intense bands observed at
10ꢀ5 mol Lꢀ1 in ethanol, in the range 200–500 nm. The 230–240 nm for the complexes are assigned to intraligand
ꢄ
weak bands centered at 330 nm for 1 and 334 nm for 2 are p–p transition. The bands centered at 518 nm for 1 and
attributed to intramolecular charge transfer transitions from 515 nm for 2 are attributed to the ligand-to-metal charge
the pp orbital on the nitrogen and oxygen to the empty d transfer transitions (LMCT).[24]

6
M. LIANG ET AL.
2. Gordon, C. P.; Engler, H.; Tragl, A. S.; Plodinec, M.;
Lunkenbein, T.; Berkessel, A.; Teles, J. H.; Parvulescu, A.-N.;
Coperet, C. Efficient Epoxidation over Dinuclear Sites in
Titanium Silicalite-1. Nature 2020, 586, 708–713. DOI: 10.1038/
s41586-020-2826-3.
3. Xu, D.; Sun, Q.; Lin, J.; Sun, W. Ligand Regulation for
Manganese-Catalyzed Enantioselective Epoxidation of Olefins
without Acid. Chem Commun (Camb). 2020, 56, 13101–13104.
DOI: 10.1039/d0cc04440g.
4. Topic, E.; Pisk, J.; Agustin, D.; Jendrlin, M.; Cvijanovic, D.;
Vrdoljak, V.; Rubcic, M. Discrete and Polymeric Ensembles
Based on Dinuclear Molybdenum(vi) Building Blocks with
Adaptive Carbohydrazide Ligands: From the Design to Catalytic
Epoxidation. New J. Chem. 2020, 44, 8085–8097. DOI: 10.1039/
D0NJ01045F.
5. Sadhukhan, D.; Ray, A.; Pilet, G.; Rizzoli, C.; Rosair, G. M.;
Gomez-Garcia, C. J.; Signorella, S.; Bellu, S.; Mitra, S. Weak
Interactions Modulating the Dimensionality in Supramolecular
Architectures in Three New Nickel(II)-Hydrazone Complexes,
Magnetostructural Correlation, and Catalytic Potential for
Epoxidation of Alkenes under Phase Transfer Conditions. Inorg.
Chem. 2011, 50, 8326–8339. DOI: 10.1021/ic200846j.
Catalytic property
The complexes show good catalytic property in the oxida-
tion of various olefins to their corresponding epoxides. The
details of catalytic properties with respect to epoxidation of
olefins with the complexes as catalysts are given in Table 3.
Good epoxide yields and selectivity were observed for all ali-
phatic and aromatic substrates. The results of catalytic stud-
ies using the catalysts reveal that the efficiency of catalyst
toward all the substrates is similar with maximum conver-
sion, TON, and selectivity. When H2O2 was used as a sole
oxidant the catalytic efficiency is not high, but when
NaHCO3 was added as a co-catalyst the efficiency of the sys-
tem increases many times. The key aspect of such a reaction
is that H2O2 and hydrogen carbonate react in an equilib-
rium process to produce peroxymonocarbonate, HCO4
which is a more reactive nucleophile than H2O2 and speeds
up the epoxidation reaction.
ꢀ
,
6. Bagherzadeh, M.; Zare, M.; Salemnoush, T.; Ozkar, S.; Akbayrak,
S. Immobilization of Dioxomolybdenum(VI) Complex Bearing
Conclusion
Salicylidene
2-Picoloyl
Hydrazone
on
Chloropropyl
A mononuclear and a dinuclear oxidovanadium(V) com-
plexes with similar aroylhydrazone ligands 2-amino-N0-(2-
hydroxybenzylidene)benzohydrazide and N0-(2-hydroxyben-
zylidene)-4-hydroxybenzohydrazide have been prepared and
structurally characterized using X-ray structure analysis. The
V atoms in the mononuclear and dinuclear complexes have
square pyramidal and octahedral geometry, respectively. The
slight difference of the aroylhydrazones leads to the forma-
tion of different complexes. Both complexes showed effective
catalytic property on the oxidation of various olefins to their
corresponding epoxides.
Functionalized SBA-15: A Highly Active, Selective and Reusable
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Supplementary material
CCDC reference numbers 1851433 (1) and 1851434 (2) con-
tain the supplementary crystallographic data for this article.
These data can be obtained free of charge at http://www.
ccdc.cam.ac.uk, or from Cambridge Crystallographic Data
Center, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: þ44
1223 336 033; Email: deposit@ccdc.cam.ac.uk.
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Disclosure statement
No potential conflict of interest was reported by the author(s).
Funding
This work was financially supported by the Fundamental Research
Funds in Heilongjiang Provincial Universities (Project No. 135409307).
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