Synthesis and crystal structures of the dioxovanadium complexes [VO 2L1] and [VO2L2]2

Article abstract of DOI:10.1134/S1070328412060073

Two new oxovanadium complexes, [VO₂L₁] (I) and [VO₂L₂]₂ (II), where L₁ and L ₂ are the deprotonated forms of 4-bromo-2-[(2-diethylaminoethylimino) methyl]phenol (HL₁) and 4-bromo-2-{[2-(2-hydroxyethylamino) ethylimino]methyl}phenol (HL₂), respectively, have been synthesized and characterized by IR spectra and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P2₁/n, a = 14.300(3), b = 7.010(2), c = 15.460(2) A, β = 107.401(2)°, V = 1478.7(5) A³, Z = 4. The crystal of II is monoclinic: space group P2 ₁/c, a = 7.270(2), b = 15.373(3), c = 11.893(3) A, β = 99.302(2)°, V = 1311.8(5) A³, Z = 2. Complex I is a mononuclear dioxovanadium(IV) complex. Complex II is a centrosymmetric dinuclear dioxovanadium(V) complex with a V·V distance of 3.117(2) A. The V atom in I is in a distorted square-pyramidal coordination, and that in II is in an octahedral coordination. The difference in the structures of the complexes is largely induced by the hydrogen bonds during the selfassembly process. Pleiades Publishing, Ltd., 2012.

Full text of DOI:10.1134/S1070328412060073

ISSN 1070ꢀ3284, Russian Journal of Coordination Chemistry, 2012, Vol. 38, No. 6, pp. 409–415. © Pleiades Publishing, Ltd., 2012.
Synthesis and Crystal Structures of the Dioxovanadium Complexes
1
[VO2L1] and [VO2L2]2
S. Y. Liua, * and Y. P. Mab
a College of Chemistry and Pharmacy, Taizhou University, Taizhou Zhejiang, 317000 P.R. China
b Department of Chemistry, Liaoning Normal University, Dalian, 116029 P.R. China
*eꢀmail: liushiyong2010@yahoo.cn
Received April 5, 2011
Abstract
—
Two new oxovanadium complexes, [VO2L1] (I) and [VO2L2]2 (II), where L1 and L2 are the deproꢀ
tonated forms of 4ꢀbromoꢀ2ꢀ[(2ꢀdiethylaminoethylimino)methyl]phenol (HL1) and 4ꢀbromoꢀ2ꢀ{[2ꢀ(2ꢀ
hydroxyethylamino)ethylimino]methyl}phenol (HL2), respectively, have been synthesized and characterized
by IR spectra and single crystal Xꢀray diffraction. The crystal of
14.300(3), = 7.010(2), = 15.460(2) = 107.401(2)
= 1478.7(5) Å3
oclinic: space group 21/ = 7.270(2), = 15.373(3), = 11.893(3) = 99.302(2)
= 2. Complex is a mononuclear dioxovanadium(IV) complex. Complex II is a centrosymmetric dinuclear
dioxovanadium(V) complex with a V⋅⋅⋅V distance of 3.117(2) . The V atom in is in a distorted squareꢀpyraꢀ
I
is monoclinic: space group
= 4. The crystal of II is monꢀ
= 1311.8(5) Å3
P21/n, a =
b
c
c
Å,
β
°
,
V
, Z
P
,
a
b
c
Å,
β
°
,
V
,
Z
I
Å
I
midal coordination, and that in II is in an octahedral coordination. The difference in the structures of the
complexes is largely induced by the hydrogen bonds during the selfꢀassembly process.
DOI: 10.1134/S1070328412060073
INTRODUCTION
ent of the benzene ring can be used to modify the coꢀ
ordination geometry and/or a number of vanadium atꢀ
oms by preventing dimerization pathways [9]. To furꢀ
ther explore the role in the synthesis of such
complexes [10], in this paper two new oxovanadium
Much attention has been focused on the Schiff
bases and their complexes in the fields of coordination
chemistry and biological chemistry [1–3]. Vanadium
compounds present innumerous pharmacological apꢀ
plications as antitumorals, antimicrobials and insulinꢀ
mimics [4–6]. It has been demonstrated that the insuꢀ
lin effects of promoting glucose uptake and inhibiting
lipolysis can be duplicated by vanadium. It is known
that there is trigonal bipyramidal vanadium within the
phosphateꢀmetabolizing enzyme [7, 8]. Mokry and
complexes, [VO2L1] ( ) and [VO2L2]2 (II), where
I
L1 and L2 are the deprotonated forms of 4ꢀbromoꢀ2ꢀ
[(2ꢀdiethylaminoethylimino)methyl]phenol (HL1)
and 4ꢀbromoꢀ2ꢀ{[2ꢀ(2ꢀhydroxyethylamino)ethylimiꢀ
no]methyl}phenol (HL2), respectively, were syntheꢀ
coworkers reported that the steric bulk of the substituꢀ sized and characterized:
H
Br
N
Br
N
N
N
OH
OH
(HL1)
OH
(HL2)
EXPERIMENTAL
were measured with a Nicolet FTꢀIR 170ꢀSX specꢀ
trophotometer using KBr pellets in the 4000–
400 cm–1 region.
Materials and measurements. All chemicals used
were commercially available with AR grade. Eleꢀ
mental analyses (CHN) were performed using a
PerkinꢀElmer 240 elemental analyzer. IR spectra
Synthesis of the schiff bases HL1 and HL2. Two
Schiff bases were synthesized according to the general
method. A methanol solution (50 mL) of 5ꢀbromosalꢀ
1
The article is published in the original.
409

410
LIU, MA
icylaldehyde (1.0 mmol, 156.6 mg) was added dropꢀ The resulting solution was allowed to stand in air for a
wise to a stirred methanol solution (50 mL) of organic
amine (1.0 mmol, N,Nꢀdiethylethaneꢀ1,2ꢀdiamine
for HL1 and 2ꢀ(2ꢀaminoethylamino)ethanol for HL2).
few days. The brown blockꢀshaped crystals suitable for
Xꢀray singleꢀcrystal diffraction were formed at the botꢀ
tom of the vessel. The isolated product was washed
The mixture was stirred for 30 min, and the solvent was with cold methanol and dried in air. The yield
then evaporated to give and orange oil product in
quantitive yield.
was 73%.
For C22H28N4O8Br2V2
For C13H19N2OBr (HL1)
anal. calcd., %:
Found, %:
C, 35.8;
C, 35.7;
H, 3.8;
H, 3.9;
N, 7.6.
N, 7.5.
anal. calcd., %:
Found, %:
C, 52.2;
C, 52.0;
H, 6.4;
H, 6.5;
N, 9.4.
N, 9.3.
IR data (cm–1): 3227 sh. m, 1638 s, 1596 m, 1521 s,
1457 s, 1416 m, 1381 s, 1281 s, 1202 w, 1182 w, 1145 w,
1076 w, 1037 m, 932 s, 875 m, 862 s, 813 m, 723 m,
672 w, 567 w, 471 m, 437 w.
For C11H15N2O2 Br (HL2)
anal. calcd., %:
Found, %:
C, 46.0;
C, 46.1;
H, 5.3;
H, 5.3;
N, 9.8.
N, 9.7.
Xꢀray singleꢀcrystal diffraction. Diffraction intenꢀ
sities for the complexes were collected at 298(2) K
using a Bruker SMART 1000 CCD areaꢀdetector
IR spectrum (KBr;
ν
, cm–1): HL1 1635
(C=N).
ν
(C=N);
HL2 3232
ν
(N–H), 1633
ν
with Mo
K
radiation ( = 0.71073 Å). The collected
λ
α
Synthesis of [VO2L1] (I). A methanol solution
(5 mL) of VO(Acac)2 (0.1 mmol, 26.5 mg) was added
data were reduced using the SAINT program [11].
Empirical absorption corrections were applied using
the SADABS program [12]. The structures were
to a methanol solution (10 mL) of HL1 (0.1 mmol,
30.0 mg) under stirring. The mixture was stirred at
room temperature for 30 min to give a brown solution.
The resulting solution was allowed to stand in air for a
few days. The brown blockꢀshaped crystals suitable for
Xꢀray singleꢀcrystal diffraction were formed on the
bottom of the vessel. The isolated product was washed
with cold methanol and dried in air. The yield
was 67%.
solved by direct methods and refined against F
2 by fullꢀ
matrix leastꢀsquares methods using the SHELXTL
package [13]. All of the nonꢀhydrogen atoms were reꢀ
fined anisotropically. The H(2) atom attached to
N(2) in II was located from a difference Fourier map
and refined isotropically with an N–H distance reꢀ
strained to 0.90(1)
Å and with U .
iso(H) set to 0.08 Å2
Other H atoms in the complexes were placed in calꢀ
culated positions and constrained to ride on their
parent atoms. The crystallographic data for the comꢀ
plexes are summarized in Table 1. Selected bond
lengths and angles are listed in Table 2. Supplemenꢀ
tary material for structures I and II has been depositꢀ
ed with the Cambridge Crystallographic Data Centre
(nos. 820387 for (I) and 820388 for (II); deposꢀ
it@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk).
For C13H18N2O3BrV
anal. calcd., %: C, 41.0;
Found, %: C, 40.8;
H, 4.8;
H, 4.8;
N, 7.3.
N, 7.4.
IR spectrum (
, cm–1): 1636 s, 1597 m, 1519 s,
ν
1454 s, 1417 m, 1380 s, 1322 w, 1309 w, 1271 m,
1208 m, 1157 s, 1101 w, 1071 w, 1023 m, 957 s, 895 w,
871 m, 776 m, 745 m, 683 w, 663 w, 617 w, 575 m,
543 w, 471 m, 440 m.
RESULTS AND DISCUSSION
The Schiff bases HL1 and HL2 were prepared via
the reaction of equimolar quantities of 5ꢀbromosalicylꢀ
Synthesis of [VO2L2]2 (II). A methanol solution
(5 mL) of VO(Acac)2 (0.1 mmol, 26.5 mg) was added
aldehyde
and
N,Nꢀdiethylethaneꢀ1,2ꢀdiamine
to a methanol solution (10 mL) of HL2 (0.1 mmol,
28.7 mg) under stirring. The mixture was stirred at
and 2ꢀ(2ꢀaminoethylamino)ethanol, respectively, in
methanol. The two complexes were readily syntheꢀ
room temperature for 30 min to give a brown solution. sized according to the standard procedure:
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38
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SYNTHESIS AND CRYSTAL STRUCTURES OF THE DIOXOVANADIUM COMPLEXES
411
Table 1. Crystallographic data and experiment details for complexes I and II
Value
Parameter
I
II
Formula
C13H18N2O3BrV
C22H28N4O8Br2V2
738.2
FW
381.1
Crystal shape/color
Crystal system
Space group
Block/brown
Monoclinic
Block/brown
Monoclinic
P
21/n
P21/c
a
, Å
, Å
14.300(3)
7.010(2)
15.460(2)
107.401(2)
1478.7(5)
4
7.270(2)
15.373(3)
11.893(3)
99.302(2)
1311.8(5)
2
b
c
, Å
β
V
Z
, deg
, Å3
T
, K
ρcalcd, g cm–3
(000)
(Mo
298(2)
1.712
298(2)
1.869
F
768
736
μ
K
), mm–1
3.381
3.813
α
Crystal size, mm
Range, deg
0.27
×
0.23
×
0.22
0.27
×
0.23 × 0.23
θ
2.32–27.00
2.65–27.00
–9, 8; –19, 17; –15, 8
Multiꢀscan
Index range (
Type of scan
h
,
k
,
l
)
–18, 18; –8, 8; –19, 19
Multiꢀscan
Tmin
,
Tmax
0.462, 0.523
0.426, 0.474
6659
Reflections collected
11439
Independent reflections (Rint
)
3228 (0.0417)
2777 (0.0383)
1967
Reflections with
Parameters
I
≥
2σ(I
)
2305
183
176
Restraints
0
1
Goodnessꢀofꢀfit on F2
Final indeces (
indeces (all data)
Largest diff. peak and hole,
0.995
1.005
R
I
≥
2σ
(I
))
*
R
1 = 0.0331, wR2 = 0.0680
1 = 0.0590, wR2 = 0.0763
0.292, –0.317
1 2
R
R
1 = 0.0372, wR2 = 0.0790
1 = 0.0639, wR2 = 0.0874
0.388, –0.528
R
*
R
e
/Å3
= [σ Fo2 + (0.0379(Fo2 + 2Fc2)/3) ] , = [σ Fo2 + (0.0402(Fo2
w +
2
2
⎤
⎦
w(F 2 − Fc2
)
w(F 2
)
,
w
1
2
2 –1
2
⎡
*
R
=
/
wR
F ,
o
=
Fo − Fc
∑
∑
o
o
∑
∑
1
2
2
⎣
2
Fc2)/3) ]
.
2 –1
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LIU, MA
Table 2. Selected bond lengths (Å) and bond angles (deg) for the complexes
I
and II*
Bond
d
, Å
Bond
d, Å
I
V(1)–O(1)
V(1)–O(3)
V(1)–N(2)
1.9206(18)
1.6227(18)
2.209(2)
V(1)–O(2)
V(1)–N(1)
1.618(2)
2.154(2)
II
V(1)–O(1)
V(1)–O(4)
V(1)–N(1)
V(1)⋅⋅⋅V(1)i
1.917(2)
1.666(2)
2.158(3)
3.1169(12)
V(1)–O(3)
V(1)–O(4)i
V(1)–N(2)i
1.613(2)
2.319(2)
2.174(3)
Angle
ω
, deg
Angle
ω
, deg
I
O(2)V(1)O(3)
O(3)V(1)O(1)
O(3)V(1)N(1)
O(2)V(1)N(2)
O(1)V(1)N(2)
110.62(11)
97.41(9)
O(2)V(1)O(1)
O(2)V(1)N(1)
O(1)V(1)N(1)
O(3)V(1)N(2)
N(1)V(1)N(2)
102.55(9)
113.76(9)
82.41(8)
90.88(8)
76.93(8)
134.53(9)
93.92(9)
157.50(8)
II
O(3)V(1)O(4)
O(4)V(1)O(1)
O(4)V(1)N(1)
O(3)V(1)N(2)
O(1)V(1)N(2)
O(3)V(1)O(4)i
O(1)V(1)O(4)i
106.59(12)
99.59(10)
155.74(10)
94.55(11)
156.76(10)
173.22(10)
82.53(9)
O(3)V(1)O(1)
O(3)V(1)N(1)
O(1)V(1)N(1)
O(4)V(1)N(2)
N(1)V(1)N(2)
O(4)V(1)O(4)i
N(1)V(1)O(4)i
100.95(11)
95.73(11)
85.04(10)
92.35(10)
76.21(10)
78.35(10)
78.68(9)
N(2)V(1)O(4)i
80.45(9)
i
* Symmetry code: 1 –
x, 1 –
y, 1 –
z.
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SYNTHESIS AND CRYSTAL STRUCTURES OF THE DIOXOVANADIUM COMPLEXES
N
413
N
N
V
O
Br
N
MeOH
O
O
+ VO(Acac)2
Br
OH
(I)
OH
NH
Br
N
H
N
V
O
O
OH
O
Br
MeOH
N
O
+ VO(Acac)2
O
O
V
N
Br
OH
HN
HO
(II)
Prepared brown crystals of
at room temperature and soluble in DMSO, DMF,
MeCN, MeOH, and EtOH and are insoluble in water.
I
and II are stable in air posed of the phenolate O, imine N, and amine N atꢀ
oms of the deprotonated Schiff base ligand L1, and an
oxo ligand O(3). The apical position is occupied by the
It is very interesting that even if the Schiff bases are
very similar and the synthetic procedure is identical,
the final structures of the complexes are different. By
contrast with HL1, HL2 possesses the hydrogen atom
attached to the amino N(2) atom, which participates
second oxo ligand O(2). The V atom lies 0.489(2)
Å
from the mean plane of the basal atoms in the direcꢀ
tion of the apical oxo ligand. The coordinate bond
lengths in the complex are comparable with those obꢀ
served in other similar dioxovanadium complexes [14–
in the formation of the N–H⋅⋅⋅
the adjacent ligand. The two N–H⋅⋅⋅
bonds, as well as the oxo bridges in II, made the two
VO2L2] moieties more closely and formed a dimer.
For , there is no such hydrogen bond, which leads to
O
hydrogen bond with
16]. The τ value for the complex is 0.38, indicating a seꢀ
verely distorted square pyramidal coordination [17].
The molecular structure of the complex II is shown
in Fig. 2. The compound is a centrosymmetric dimeric
dioxovanadium(V) complex with the inversion center
O
hydrogen
[
I
the formation of a mononuclear dioxovanadium(V)
complex.
located at the midpoint of the two V atoms. The V⋅⋅⋅V
distance is 3.117(2) . Each V atom in the complex is
Å
sixꢀcoordinated through three bonds to oxo groups
and through bonds to the tridentate Schiff base ligand
The molecular structure of complex I is shown in
Fig. 1. The V atom is fiveꢀcoordinate in a distorted
square pyramidal geometry. The basal plane is comꢀ L2, forming an octahedral geometry. The distance beꢀ
C(8)
C(7)
C(6)
C(9)
C(5)
C(11)
C(10)
N(1)
Br(1)
C(1)
N(2)
C(12)
V(1)
C(2)
C(4)
C(3)
O(1)
O(2)
O(3)
C(13)
Fig. 1. Molecular structure of complex
I
at 30% probability displacement.
No. 6 2012
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 38

414
LIU, MA
C(10)
C(8)
C(11)
O(1
C(9)
C(7)
N(1)
O(2)
O(3)
V(1)
C(1)
N(2)
C(6)
C(4A)
C(3
A
)
C(2)
O(1)
A)
O(4)
Br(1)
C(5)
C(4)
C(3)
C(5A)
O(4
N(2
A)
C(2A)
V(1A)
Br(1A)
C(1A)
C(6A)
A)
C(7A)
O(2A)
O(3A)
N(1
A)
C(9
C(10
A)
C(8
A)
C(11
A)
A
)
Fig. 2. Molecular structure of complex II at 30% probability displacement. Atoms labeled with the suffix
position 1 – , 1 – , 1 –
A are at the symmetry
x
y
z.
x
0
z
y
Fig. 3. Molecular packing of complex II viewed along the x axis. Intermolecular hydrogen bonds are drawn as thin dashed lines.
tween atoms V(1) and O(3) is 1.613(2)
typical V=O bond. The O(4) atom is involved in the
bridge between V(1) and V(1 ) strongly coordinated
to O(4) (1.666(2) ) and weakly coordinated to O(4
(2.319(2) ). The coordinate bond lengths are compaꢀ
rable to those observed in and other similar oxovanaꢀ
dium complexes [18–20]. The distortion of the octaꢀ
hedral coordination can be observed by the coordinate
bond angles ranging from 76.2(1)° to 106.6(1)° for the
Å
, indicating a
ACKNOWLEDGMENTS
We acknowledge the Zhejiang Provincial Natural
Science Foundation of China (project no. Y4090281)
for funding this work.
A
Å
A)
Å
I
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