Synthesis and crystal structures of schiff base oxovanadium(V) complexes [VO(BN)(OCH3)]2 and [VO2(BM)]

Article abstract of DOI:10.1080/15533174.2011.591877

[VO(acac)₂] reacts with the Schiff bases N'-(2-hydroxy-4- diethylaminobenzylidene)-2-nitrobenzohydrazide (H₂BN) and N'- (2-hydroxy-4-diethylaminobenzylidene)-2-methoxybenzohydrazi de (HBM), respectively, in absolute methanol to give the oxovanadium( V) complexes [VO(BN)(OCH₃)]₂ (1) and [VO₂(BM)] (2). Both complexes were characterized by elemental analysis, infrared (IR) spectra, and single-crystal x-ray determination. The complex (1) crystallizes in the monoclinic space group P2₁/c, with a = 10.828(2), b = 18.177(4), c = 10.778(2) A, β = 106.914(3)°, V = 2029.6(7) A³, Z = 4. The complex (2) crystallizes in the triclinic space group P-1, with a = 8.459(2), b = 10.068(3), c = 11.776(3) A, α = 88.727(2), β = 88.904(3), γ = 69.486(3)°, V = 939.0(4) A³, Z = 2. Complex (1) is a centrosymmetric methoxy-bridged dimeric oxovanadium(V) compound, and complex (2) is a monomeric dioxovanadium(V) compound. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/15533174.2011.591877

This article was downloaded by: [Nipissing University]
On: 16 October 2014, At: 13:50
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer
House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthesis and Reactivity in Inorganic, Metal-Organic,
and Nano-Metal Chemistry
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/lsrt20
Synthesis and Crystal Structures of Schiff Base
Oxovanadium(V) Complexes [VO(BN)(OCH3)]2 and
[VO2(BM)]
Yong-Ming Cui a , Ying-Jie Cai a & Wu Chen a
a Engineering Research Center for Clean Production of Textile Printing, Ministry of
Education , Wuhan Textile University , Wuhan, P. R. China
Published online: 02 Dec 2011.
To cite this article: Yong-Ming Cui , Ying-Jie Cai & Wu Chen (2011) Synthesis and Crystal Structures of Schiff Base
Oxovanadium(V) Complexes [VO(BN)(OCH3)]2 and [VO2(BM)], Synthesis and Reactivity in Inorganic, Metal-Organic, and
Nano-Metal Chemistry, 41:10, 1244-1248, DOI: 10.1080/15533174.2011.591877
To link to this article: http://dx.doi.org/10.1080/15533174.2011.591877
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of
the Content. Any opinions and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied
upon and should be independently verified with primary sources of information. Taylor and Francis shall
not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other
liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or
arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 41:1244–1248, 2011
Copyright ꢀ Taylor & Francis Group, LLC
C
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2011.591877
Synthesis and Crystal Structures of Schiff Base
Oxovanadium(V) Complexes [VO(BN)(OCH3)]2 and
[VO2(BM)]
Yong-Ming Cui, Ying-Jie Cai, and Wu Chen
Engineering Research Center for Clean Production of Textile Printing, Ministry of Education, Wuhan
Textile University, Wuhan, P. R. China
H
H
[VO(acac)2] reacts with the Schiff bases N’-(2-hydroxy-4-
diethylaminobenzylidene)-2-nitrobenzohydrazide (H2BN) and N’-
(2-hydroxy-4-diethylaminobenzylidene)-2-methoxybenzohydrazi
de (HBM), respectively, in absolute methanol to give the oxo-
vanadium(V) complexes [VO(BN)(OCH3)]2 (1) and [VO2(BM)]
(2). Both complexes were characterized by elemental analysis,
infrared (IR) spectra, and single-crystal x-ray determination. The
N
N
N
N
OMe
NO2
O
O
Et2N
OH
Et2N
OH
SCH. 1. H2BN and HBM.
complex (1) crystallizes in the monoclinic space group P21/c, with methoxybenzohydrazide (HBM; Scheme 1), respectively, have
a = 10.828(2), b = 18.177(4), c = 10.778(2) Å, β = 106.914(3)◦, V
been synthesized and characterized.
= 2029.6(7) Å3, Z = 4. The complex (2) crystallizes in the triclinic
space group P-1, with a = 8.459(2), b = 10.068(3), c = 11.776(3) Å,
EXPERIMENTAL
α = 88.727(2), β = 88.904(3), γ = 69.486(3)◦, V = 939.0(4) Å3, Z
= 2. Complex (1) is a centrosymmetric methoxy-bridged dimeric
Materials and Methods
oxovanadium(V) compound, and complex (2) is a monomeric
4-Diethylaminosalicylaldehyde, 2-nitrobenzohydrazide, and
2-methoxybenzohydrazide were purchased from Alfa Aesar.
[VO(acac)2] was prepared according to the literature method.[9]
All chemicals and solvents were of analytical grade and used as
obtained. Microanalyses of the Schiff bases and the oxovana-
dium(V) complexes were performed with a Vario EL III CHNOS
elemental analyzer. The infrared spectra were recorded as KBr
pellets with an FTS-40 spectrophotometer.
dioxovanadium(V) compound.
Keywords crystal structure, coordination compound, oxovana-
dium(V) complex, Schiff base
INTRODUCTION
Oxovanadium complexes have received considerable atten-
tion in the context of the role in living organisms.[1–3] This inter-
est stems from the discovery of two kinds of vanadium enzymes,
vanadium nitrogenases and vanadate-dependent haloperox-
idases.[4,5] The insulin-like effect of vanadium complexes is
another intriguing and promising feature that has further stimu-
lated vanadium coordination chemistry.[6–8] For the present pa-
per, two new oxovanadium(V) complexes, [VO(BN)(OCH3)]2
(1) and [VO2(BM)] (2), derived from the Schiff bases N’-(2-
hydroxy-4-diethylaminobenzylidene)-2-nitrobenzohydrazide
(H2BN) and N’-(2-hydroxy-4-diethylaminobenzylidene)-2-
Crystal Structure Determination
Data were collected on a Bruker smart 1000 CCD area
diffractometer using a graphite monochromator Mo Kα radia-
tion (λ = 0.71073 Å) at 298(2) K. The data were corrected with
SADABS programs and refined on F2 with Siemens SHELXL
software.[10,11] The structures were solved by direct methods
and difference Fourier syntheses. All non-hydrogen atoms were
refined anisotropically. The hydrogen atoms were placed in cal-
culated positions and included in the last cycles of refinement.
Crystal data and details of the data collection and refinement are
listed in Table 1. Selected coordinate bond lengths and angles
are listed in Table 2.
Received 9 January 2011; accepted 16 February 2011.
This work was financed by the Education Office of Hubei Province Preparation
(Q20101610).
H2BN
Address correspondence to Wu Chen, Engineering Research Cen-
A mixture of 4-diethylaminosalicylaldehyde (1.93 g, 10
mmol) and 2-nitrobenzohydrazide (1.81 g, 10 mmol) in 100
mL methanol was refluxed for 2 h. After reducing the solvent to
ter for Clean Production of Textile Printing, Ministry of Educa-
tion, Wuhan Textile University, Wuhan 430073, P. R. China. E-mail:
cym@smail.hust.edu.cn
1244

SCHIFF BASE OXOVANADIUM COMPLEXES
1245
TABLE 1
TABLE 2
Crystallographic data for complexes (1) and (2)
Selected bond lengths (Å) and angles (◦) for the complexes (1)
and (2)
(1)
(2)
(1)
V1–O1
V1–O5
V1–O6A
O5–V1–O6
O6–V1–O1
O6–V1–O2
O5–V1–N1
O1–V1–N1
O5–V1–O6A
O1–V1–O6A
N1–V1–O6A
Formula
Formula weight
Crystal system
Space group
a (Å)
C19H21N4O6V
452.3
monoclinic
P21/c
10.828(2)
18.177(4)
10.778(2)
90
106.914(3)
90
2029.6(7)
4
298(2)
0.71073
1.480
C19H22N3O5V
423.3
triclinic
P-1
8.459(2)
10.068(3)
11.776(3)
88.727(2)
88.904(3)
69.486(3)
939.0(4)
2
298(2)
0.71073
1.497
0.565
7849
1.8121 (17)
1.5810 (19)
2.4474 (17)
103.72 (9)
104.31 (7)
88.83 (7)
96.47 (9)
83.72 (7)
178.56 (8)
77.95 (7)
V1–O2
V1–O6
V1–N1
O5–V1–O1
O5–V1–O2
O1–V1–O2
O6–V1–N1
O2–V1–N1
O6–V1–O6A
O2–V1–O6A
1.9329 (16)
1.8103 (15)
2.0840 (19)
102.54 (10)
99.71 (9)
150.47 (8)
155.86 (8)
74.67 (7)
b (Å)
c (Å)
α (◦)
β (◦)
74.84 (7)
80.29 (6)
γ (◦)
V (Å3)
Z
84.93 (7)
(2)
V1–O1
V1–O4
V1–N1
O5–V1–O4
O4–V1–O1
O4–V1–O2
O5–V1–N1
O1–V1–N1
T (K)
λ (Å)
1.9034 (17)
1.6220 (17)
2.1439 (19)
110.13 (10)
98.05 (8)
91.71 (8)
107.54 (9)
82.12 (7)
V1–O2
V1–O5
2.0293 (17)
1.621 (2)
ρcalcd. (g cm−3
)
µ (mm−1
)
0.533
13890
4291
3242
O5–V1–O1
O5–V1–O2
O1–V1–O2
O4–V1–N1
O2–V1–N1
104.26 (9)
97.95 (9)
150.81 (8)
140.97 (9)
73.19 (7)
Measured reflections
Independent reflections
Observed reflections (I
> 2σ(I))
3908
3481
Rint
0.0369
0.0459
0.1088
1.044
0.0182
0.0475
0.1333
1.038
a
R1
b
wR2
GOF on F2
mmol), and the resulting reaction mixture was refluxed on a
water bath for 1 h, and then cooled to room temperature, yielding
a deep brown solution. The solution was allowed to stand still at
ambient temperature to slow evaporation of the solvent, yielding
brown crystals of (1). Yield 0.378 g (84%). Anal.: Calcd. for
C19H21N4O6V (%): C, 50.5; H, 4.7; N, 12.4. Found (%): C,
50.3; H, 4.9; N, 12.6. IR (KBr, νmax/cm−1): 1608 (C N), 1504
(NO2, asym), 1352 (NO2, sym), 1338 (C–O, enolic), 1218 (C–O,
phenolate), 1023 (N–N), 973 (V O), 495, 446 (V–O, V–N).
ꢀ
ꢀ
aR1 = (ꢁFo| − |Fcꢁ)/ |Fo|.
ꢀ
ꢀ
2
2 2
2 2
2
bwR2 = { [w(Fo – Fc ) ]/ [w(Fo ) ]}1/2, w(1) = 1/[σ2(Fo ) +
2
(0.058P)2 + 0.3908P], w(2) = 1/[σ2(Fo ) + (0.0836P)2 + 0.4924P],
2
2
where P = (Fo + 2Fc )/3.
20 mL and cooling to room temperature, the precipitated yellow
solid was filtered off, washed with methanol, and dried. Recrys-
tallization from methanol yielded pure product of H2BN as a
yellow solid. Yield 2.62 g (88%). Anal.: Calcd. for C15H13N3O4
(%): C, 60.2; H, 4.4; N, 14.0. Found (%): C, 59.9; H, 4.4; N,
14.1. Infrared (IR) (KBr, νmax/cm−1): 3356 (OH), 3227 (NH),
1655 (C O), 1643 (C N).
[VO2(BM)] (2)
This complex was prepared by following the same procedure
outlined for (1), yielding light green single crystals. Yield 0.272
g (64%). Anal.: Calcd. for C19H22N3O5V (%): C, 53.9; H, 5.2;
N, 9.9. Found (%): C, 54.3; H, 5.4; N, 9.8. IR (KBr, νmax/cm−1):
3184 (NH), 1606 (C N), 1422 (C O), 924 (V O), 456, 404
(V–O, V–N).
HBM
This ligand was prepared by following the same procedure
outlined for H2BN, with 2-nitrobenzohydrazide replaced with 2-
methoxybenzohydrazide (1.66 g, 10 mmol), yielding a colorless
solid product. Yield 2.71 g (95%). Anal.: Calcd. for C16H16N2O3 RESULTS AND DISCUSSION
(%): C, 67.6; H, 5.7; N, 9.8. Found (%): C, 67.4; H, 5.8; N, 10.0.
IR (KBr, νmax/cm−1): 3355 (OH), 3223 (NH), 1651 (C O),
1645 (C N).
The overview of the two complexes is shown in Scheme
2. Reaction between equimolar quantities of [VO(acac)2] with
H2BM and HBN, respectively, in absolute methanol, afforded
[VO(BN)(OCH3)]2 and [VO2(BM)]. The ligands BN and BM
adopt enolic tautomeric form on complexation. On aerial oxida-
tion in methanol, the VIV atom in VO(acac)2 is changed to VV
in the complexes.
[VO(BN)(OCH3)]2 (1)
A stirred solution of H2BN (0.299 g, 1 mmol) in absolute
methanol (20 mL) was mixed with [VO(acac)2] (0.265 g, 1

1246
Y.-M. CUI ET AL.
N
N
O
NO2
OMe
O
MeO
Et2N
O
V
H
N
MeO
NO2
N
O
V
Et2N
O
O
O
Et2N
O
N
V
N
O
O
SCH. 2. [VO(BN)(OCH3)]2 and [VO2(BM)].
Structure Description
[VO(BN)(OCH3)]2 (1)
The crystal structure of (1) with atom numbering scheme is
shown in Figure 1. The complex is a centrosymmetric dimeric
oxovanadium(V) compound, with V···V distance of 3.404(1)
Å. The ligand BN forms one five-membered ring and one six-
membered chelate ring with bite angles of 74.7(1) and 83.7(1)◦.
The V atom is in a distorted octahedral O5N coordination sphere.
The phenolate O, imine N, and enolic O atoms of BN and one
methoxy O atom constitute the equatorial plane, with mean de-
viation of 0.016 Å. The two axial positions are occupied by
one oxo O atom and another methoxy O atom. The displace-
ment of the V atom from the equatorial plane toward the ax-
FIG. 1. ORTEP plots (30% probability level) and numbering scheme for (1).
group in the complex indicates weak coordination of the O6A
atom at the axial position.
In the crystal structure of the complex (Figure 2), the
molecules are stacked together by weak π···π and C–H···π
interactions among the molecules (Tables 3 and 4).
[VO2(BM)] (2)
The crystal structure of (2) with atom numbering scheme is
ial oxo group is 0.360(2) Å. The cis bond angles are in the shown in Figure 3. The ligand BM forms one five-membered
range 74.8(1)–104.3(1)◦, and the trans bond angles are within ring and one six-membered chelate ring with bite angles of
150.5(1)–178.6(1)◦. The V–O and V–N bond lengths in the 73.2(1) and 82.1(1)◦. The V atom is five-coordinate in an O4N
complex are comparable with the bond lengths reported for ox- square pyramidal coordination, as evidenced by the value of
ovanadium(V) complexes with similar ligands.[12–14] As com- τ (0.16), which is defined as (β – α)/60,[15] where α and
monly observed in analogous species, the elongated V1–O6A β are the two largest angles subtended at the V atoms. For
(symmetry code for A: 2 – x, 2 – y, 1 – z) bond trans to the oxo an ideal square-pyramidal geometry τ is 0, and for an ideal
TABLE 3
π···π Interactions for (1) and (2)
Distance between ring
centroids (Å)
Perpendicular distance
of Cg(I) on Cg(J) (Å)
Perpendicular distance
of Cg(J) on Cg(I) (Å)
Cg(I)···Cg(J)a
Dihedral angle (◦)
(1)
Cg(1)···Cg(1)#1
Cg(1)···Cg(2)#2
Cg(2)···Cg(3)#3
Cg(2)···Cg(3)#2
Cg(3)···Cg(1)#4
5.370
4.833
4.766
5.995
5.821
0.03
18.06
50.58
50.58
32.96
2.925
2.675
1.705
4.442
0.030
2.925
3.762
4.498
3.378
3.102
(2)
Cg(4)···Cg(4)#5
Cg(4)···Cg(5)#6
Cg(4)···Cg(5)#5
Cg(5)···Cg(5)#6
Cg(5)···Cg(6)#5
4.110
3.902
4.957
4.770
3.766
0.00
2.01
2.01
0.03
10.49
3.274
3.500
3.580
3.277
3.556
3.274
3.558
3.647
3.277
3.705
aCg(1), Cg(2), and Cg(3) are the centroids of the V(1)-O(2)-C(8)-N(2)-N(1), C(1)-C(2)-C(3)-C(4)-C(5)-C(6), and C(9)-C(10)-C(11)-C(12)-
C(13)-C(14) of (1). Cg(4), Cg(5), and Cg(6) are the centroids of the V(1)-O(2)-C(8)-N(2)-N(1), C(1)-C(2)-C(3)-C(4)-C(5)-C(6), and C(9)-
C(10)-C(11)-C(12)-C(13)-C(14) of (2). Symmetry codes: #1, – x, – y, 1 – z; #2, 1 – x, – y, 1 – z; #3, x, y, –1 + z; #4, 1 – x, – y, 2 – z; #5, 1 – x, 1
– y, – z; #6, – x, 1 – y, – z.

SCHIFF BASE OXOVANADIUM COMPLEXES
1247
TABLE 4
X–H···Cg interactions for (1)
X–H···Cg(J)a
H···Cg (Å) X–H···Cg (◦) X···Cg (Å)
C(13)–H(13)···Cg(2)#7
C(15)–H(15A)···Cg(2)#8
C(16)–H(16C)···Cg(3)#2
2.79
2.91
2.89
138
142
126
3.540
3.721
3.538
aCg(2) and Cg(3) are the centroids of the C(1)-C(2)-C(3)-C(4)-
C(5)-C(6) and C(9)-C(10)-C(11)-C(12)-C(13)-C(14) of (1). Symmetry
codes: #2, 1 – x, – y, 1 – z; #7, x, y, 1 + z; #8, x, 1/2 – y, –1/2 + z.
trigonal-bipyramidal geometry τ is 1. The V–O and V–N bond
lengths in the complex are comparable with the bond lengths
in (1), and also comparable to those reported for dioxovana-
dium(V) complexes with similar ligands.[16–18]
In the crystal structure of the complex (Figure 4), the
molecules are stacked together by weak π···π interactions
among the molecules (Tables 3 and 4).
FIG. 2. Molecular packing diagram for (1), viewed along the c axis.
It is notable that the distance between atoms C8 and N2 in
(1) is shorter than that in (2), and the distance between atoms C8
and O2 in (1) is longer than that in (2), indicating the enolization
of the N2–C8–O2 group in (1). The nitro group of (1) located
at the same site of the V coordination, while the methoxy group
of (2) located at the opposite site of the V coordination, which
is caused by the intramolecular N–H···O hydrogen bond in (2)
(Table 5), and no such linkage in (1).
IR Spectra
The weak and broad bands in the region 3340–3360 cm−1 of
the Schiff bases are assigned to the ν(O–H) vibrations. The ν(C
= O) vibration at 1655 cm−1 and the sharp ν(NH) vibration of
3227 cm−1 for H2BN are absent in the complex (1), indicating
the enolization of the amide functionality and subsequent proton
replacement by the vanadium atom, which is accord with the
results analyzed by the x-ray determination. The sharp band at
3184 cm−1 in the spectrum of complex (2) indicates that the H
atom is attached to the N atom of the amide group. The ν(C-
O) (enolic) mode of (1) appears at 1338 cm−1, and the ν(C
= O) mode of (2) appears at 1422 cm−1. The strong bands at
1608 cm−1 in (1) and 1606 cm−1 in (2) are assigned to the
azomethine groups. The bands observed in the range 924–973
cm−1 for both complexes are assigned to the V = O stretches.
FIG. 3. ORTEP plots (30% probability level) and numbering scheme for (2).
TABLE 5
Hydrogen bonding for (2)
d(D–H) d(H···A) d(D···A) Angle(D–H···A)
D–H···Aa
(Å)
(Å)
(Å)
(◦)
N2–H2···O5i 0.900(10) 2.25(2) 3.044(3)
148(3)
119(3)
N2–H2···O3 0.900(10) 2.06(3) 2.615(2)
aSymmetry code: (i) 1 – x, 1 – y, – z.
FIG. 4. Molecular packing diagram for (2), viewed along the c axis.

1248
Y.-M. CUI ET AL.
The bands indicative of the V–O and V–N bands are in the range
404–495 cm−1. The asymmetric and symmetric vibrations of the
6. Goldwaser, I.; Gefel, D.; Gershonov, E.; Fridkin, M.; Shechter, Y. Insulin-
like effects of vanadium: Basic and clinical implications. J. Inorg. Biochem.
2000, 80, 21–25.
7. Crans, D.C. Chemistry and insulin-like properties of vanadium(IV) and
vanadium(V) compounds. J. Inorg. Biochem. 2000, 80, 123–131.
8. Ballistreri, F.P.; Barbuzzi, E.G.M.; Tomaselli, G.A.; Toscano, R.M. Insulin
mimesis of vanadium derivatives. oxidation of cysteine by V(V) oxo diper-
oxo complexes. J. Inorg. Biochem. 2000, 80, 173–176.
9. Rowe, R.A.; Jones, M.M. Vanadium(IV) oxy(acetylacetonate): Bis(2,4-
pentanediono)oxovanadium(IV). Inorg. Synth. 1957, 5, 113–116.
10. Sheldrick, G.M. SADABS; Siemens Analytical X-ray Instrument Division:
Madison, WI, 1995.
11. Sheldrick, G.M. SHELXS97 Program for Solution of Crystal Structures;
University of Go¨ttingen: Go¨ttingen, Germany, 1997.
nitro groups in complex (1) are at 1504 and 1352 cm−1
.
CONCLUSION
Using the similar tridentate Schiff bases prepared from 4-
diethylaminosalicylaldehyde with 2-nitrobenzohydrazide and
2-methoxybenzohydrazide, respectively, two new oxovana-
dium(V) complexes have been synthesized and characterized
for their structures. The dianionic BN ligand and the de-
protonated BM ligand coordinate to the V atom through
the phenolate-O, the imine-N, and the enolic or carbonylO
atoms.
12. Sarkar, A.; Pal, S. Complexes of oxomethoxovanadium(V) with triden-
tate thiobenzhydrazide based Schiff bases. Inorg. Chim. Acta 2008, 361,
2296–2304.
13. da S. Maia, P.I.; Deflon, V.M.; de Souza, E.J.; Garcia, E.; de Sousa,
G.F.; Batista, A.A.; de Figueiredo, A.T.; Niquet, E. Biomimetic oxovana-
dium(IV) and (V) complexes with a tridentate (N,N,O)-donor hydrazonic
ligand. Two x-ray crystal structure modifications of (2-acetylpyridine-
benzoylhydrazonato)dioxovanadium(V). Transition Metal Chem. 2005, 30,
404–410.
14. Sangeetha, N.R.; Kavita, V.; Wocadlo, S.; Powell, A.K.; Pal, S. Vana-
dium(V) complexes of O,N,O-donor tridentate ligands containing the
{VVO(OMe)}2+ unit: Syntheses, structures and properties. J. Coord. Chem.
2000, 51, 55–66.
SUPPLEMENTARY MATERIAL
CCDC 806701 and 806702 contain the supplementary crys-
tallographic data for this paper. These data can be obtained free
of charge from the Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data request/cif.
REFERENCES
1. Baran, E.J. Oxovanadium(IV) and oxovanadium(V) complexes relevant to
biological systems. J. Inorg. Biochem. 2000, 80, 1–10.
2. Sakurai, H.; Sano, H.; Takino, T.; Yasui, H. An orally active antidi-
abetic vanadyl complex, bis(1-oxy-2-pyridinethiolato)oxovanadium(IV),
with VO(S2O2) coordination mode; In vitro and in vivo evaluations in
rats. J. Inorg. Biochem. 2000, 80, 99–105.
3. de Rio, D.; Galindo, A.; Tejedo, J.; Bedoya, F.J.; Lenco, A.; Mealli,
C. Synthesis, antiapoptotic biological activity and structure of an oxo-
vanadium(IV) complex with an OOO ligand donor set. Inorg. Chem. Com-
mun. 2000, 3, 32–34.
4. Sigel, H.; Sigel, A. (Eds.), Metal Ions in Biological Systems: Vanadium and
Its Role in Life, vol. 31; Marcel Dekker: New York, 1995.
5. Rehder, D. The coordination chemistry of vanadium as related
to its biological functions. Coord. Chem. Rev. 1999, 182, 297–
322.
15. Addison, A.W.; Rao, T.N.; Reedijk, J.; van Rijn, J.; Verschoor, G.C. Synthe-
sis, structure, and spectroscopic properties of copper(II) compounds con-
taining nitrogen–sulphur donor ligands; The crystal and molecular structure
of aqua-1,7-bis(N-methylbenzimidazol-2-yl)-2,6-dithiaheptane.copper(II)
perchlorate. J. Chem. Soc. Dalton Trans. 1984, 1349–1356.
16. Maurya, M.R.; Khurana, S.; Zhang, W.; Rehder, D. Biomimetic oxo-, dioxo-
and oxo-peroxo-hydrazonato-vanadium(IV/V) complexes. J. Chem. Soc.
Dalton Trans. 2002, 3015–3023.
17. Mokry, L.M.; Carrano, C.J. Steric control of vanadium(V) coordination ge-
ometry: A mononuclear structural model for transition-state-analog Rnase
inhibitors. Inorg. Chem. 1993, 32, 6119–6121.
18. Root, C.A.; Hoeschele, J.D.; Cornman, C.R.; Kampf, J.W.; Pecoraro,
V.L. Structural and spectroscopic characterization of dioxovanadium(V)
complexes with asymmetric Schiff base ligands. Inorg. Chem. 1993, 32,
3855–3861.