Neutral dioxovanadium(V) complexes of biomimetic hydrazones ONO donor ligands of bioinorganic and medicinal relevance: Synthesis via air oxidation of bis(acetylaceto-nato)oxovanadium(IV), characterization, biological activity and 3D molecular modeling

Article abstract of DOI:10.1016/j.molstruc.2006.09.022

The interaction of bis(acetylacetonato)oxovanadium(IV), [VO(acac)₂] with biomimetic hydrazone ONO donor ligands HL in 1:1 mole ratio [where, HL = N-(4′-benzoylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (bmphp-inH, I), N-(4′-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (bumphp-inH, II), N-(4′-acetylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (amphp-inH, III), N-(3′-methyl-1′-phenyl-4′-propionylidene-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (mphpp-inH, IV) and N-(4′-iso-butyrylidene-3′-methyl-1′-phenyl-2′-pyrazolin-5′-one)-isonicotinic acid hydrazide (iso-bumphp-inH, V)] in a mixed solvent (ethanol-methanol, 1:10) via aerial oxidation for 2-3 days yield dioxovanadium(V) complexes of composition [VO₂(L)(H₂O)] · H₂O. The compounds so obtained were characterized on the basis of elemental analyses, thermogravimetry, vanadium determination, IR, Electronic, ⁵¹V NMR, ¹H NMR and mass spectral studies. The 3D molecular modeling and analysis for bond lengths and bond angles have also been carried out for one of the representative compounds, [VO₂(ampph-in)(H₂O)] (3).

Full text of DOI:10.1016/j.molstruc.2006.09.022

Journal of Molecular Structure 833 (2007) 133–144
www.elsevier.com/locate/molstruc
Neutral dioxovanadium(V) complexes of biomimetic hydrazones
ONO donor ligands of bioinorganic and medicinal relevance: Synthesis
via air oxidation of bis(acetylaceto-nato)oxovanadium(IV),
characterization, biological activity and 3D molecular modeling
*
R.C. Maurya , S. Rajput
Coordination Chemistry Laboratory, Department of P.G. Studies and Research in Chemistry, R.D. University, Jabalpur, MP 482 001, India
Received 13 July 2006; accepted 12 September 2006
Available online 13 November 2006
Abstract
The interaction of bis(acetylacetonato)oxovanadium(IV), [VO(acac)
mole ratio [where, HL = N-(4 -benzoylidene-3 -methyl-1 -phenyl-2 -pyrazolin-5 -one)-isonicotinic acid hydrazide (bmphp-inH, I),
2
] with biomimetic hydrazone ONO donor ligands HL in 1:1
0
0
0
0
0
0
0
0
0
0
0
0
N-(4 -butyrylidene-3 -methyl-1 -phenyl-2 -pyrazolin-5 -one)-isonicotinic acid hydrazide (bumphp-inH, II), N-(4 -acetylidene-3 -methyl-
0
0
0
0
0
0
0
0
1
-phenyl-2 -pyrazolin-5 -one)-isonicotinic acid hydrazide (amphp-inH, III), N-(3 -methyl-1 -phenyl-4 -propionylidene-2 -pyrazolin-5 -
one)-isonicotinic acid hydrazide (mphpp-inH, IV) and N-(4 -iso-butyrylidene-3 -methyl-1 -phenyl-2 -pyrazolin-5 -one)-isonicotinic acid
hydrazide (iso-bumphp-inH, V)] in a mixed solvent (ethanol–methanol, 1:10) via aerial oxidation for 2–3 days yield dioxovanadium(V)
0
0
0
0
0
2 2 2
complexes of composition [VO (L)(H O)] Æ H O. The compounds so obtained were characterized on the basis of elemental analyses, ther-
5
1
1
mogravimetry, vanadium determination, IR, Electronic, V NMR, H NMR and mass spectral studies. The 3D molecular modeling and
analysis for bond lengths and bond angles have also been carried out for one of the representative compounds, [VO (ampph-in)(H O)] (3).
2
2
Ó 2006 Elsevier B.V. All rights reserved.
Keywords: Neutral dioxovanadium(V) complexes; Biomimetic hydrazones; Bioinorganic; Medicinal relevance; 3D molecular modeling
1
. Introduction
redox interplay, whether V(V)/V(IV) or V(IV)/V(III),
increases the versatility of these element in the biological
milieu [2]. Vanadium may or may not play an essential role
in normal mammalian metabolism [3], however, at phar-
macological concentrations, as a potential therapeutic
agent, it is attracting increasing attention [4,5].
The coordination chemistry of vanadium with multiden-
tate ligands has achieved a special status in the last decade
because of its catalytic [6,7] and medicinal [8–11] input.
Structural and/or functional models for vanadate-depen-
dent haloperoxidases, for vanadium nitrogenases and other
biologically active vanadium compounds have further stim-
ulated vanadium coordination chemistry [12–15]. The
active site structures of the vanadate-dependent haloperox-
idases have been revealed by X-ray diffraction studies.
Vanadium is normally present at very low concentra-
ꢀ
8
tions (<10 M) in virtually all cells in plants and animals.
Vanadium in oxidation states III, IV and V readily forms
V–O bonds and comfortably binds N and S as well,
forming chemically robust, coordination compounds.
Vanadium(V) in particular, in stereochemically flexible-
coordination geometries ranging from tetrahedral and
octahedral to trigonal pyramidal and pentagonal bipyrami-
dal is thermodynamically plausible [1]. The potential for
*
Corresponding author.
E-mail addresses: rcmauryajb@dataone.in, rcmaurya@sancharnet.in
(R.C. Maurya).
0
022-2860/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.molstruc.2006.09.022

134
R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
Accordingly, the vanadate ion is distorted towards a trigo-
nal pyramid, thus providing a fifth coordination site which
is occupied by N of a histidine, covalently linking the van-
adate ion to the protein [16–18]. These enzymes lose their
activity upon reduction or removal of vanadate. Re-oxida-
tion, or reconstitution of the apo-enzymes with vanadate,
fully restores their activity [12], demonstrating that vanadi-
X
OH
N
N
H C
3
X= -C H5
(bmphp-inH)
(bumphp-inH)
(amphp-inH)
(mphpp-inH)
6
-
C H
3
7
O
N
-CH3
N
N
-C H
2
5
-
iso-C H7 (iso-bumphp-inH)
3
3
+
þ
um(V) (VO or VO ) is essential for the catalytic activity.
2
Fig. 2. Structures of aroylhydrazones.
Different kinds of oxovanadium(V) complexes have been
studied [19–55] in this context.
Dioxovanadium(V) complexes are commonly synthe-
sized (i) by the reaction of vanadates with ONO-functional
ligands in aqueous solution [20, 43–47] (ii) by the reaction
0
0
0
0
(amphp-inH), N-(3 -methyl-1 -phenyl-4 -propionylidene-2 -
0
pyrazolin-5 -one)-isonicotinic acid hydrazide (mphpp-inH)
and N-(4 -iso-butyrylidene-3 -methyl-1 -phenyl-2 -pyrazolin-
5 -one)-isonicotinic acid hydrazide (iso-bumphp-inH)
0
0
0
0
0
of [VO(OEt) ] with appropriate ligands [51] or (iii) by oxi-
(Fig. 2). Spectral and structural aspects, biological activity
of the compounds, 3D molecular modeling and analysis
of bond lengths and bond angles for a representative
compound are reported here.
3
dation of oxovanadium(IV) complexes with KNO in H O/
2
2
MeOH [52] and (iv) by the reaction of [VO(acac)2]
acacH = acetylacetone) or VOSO4 with the ligands in
(
non-aqueous or mixed solvent media followed by oxidation
with O [48–50,56].
2. Experimental
2
A wide range of vanadium complexes have been shown
to have insulin mimetic properties in animal model systems
and cell culture. Although most known insulin-like
complexes contain vanadium in oxidation state IV, two
classes of vanadium(V) compounds, (i) monoperoxovana-
2.1. Materials
3-Methyl-1-phenyl-2-pyrazolin-5-one and vanadyl sul-
phate pentahydrate (Lancaster, UK), benzoyl chloride,
acetyl chloride and propionyl chloride and acetylacetone
(Thomas Baker Chemicals Limited, Mumbai), butyryl
chloride (S.D. fine-Chem Limited, Mumbai), iso-butyryl
chloride (E. Merck, Germany) and isonicotinic acid hydra-
zide (Aldrich chemical Co, USA), were used as supplied.
All other chemicals used were of analytical reagent grade.
nꢀ
dates [VO(O )(H O) (L–L)] (n = 0,1) [3] and diperoxo-
2
2
2
nꢀ
vanadates [VO(O ) ((L– L)]
(n = 1,2,3) [3] and (ii)
2
2
dioxovanadium(V) complexes [57–61], have recently been
found to have insulin-like properties. The (pyridine-2,
6
2
-dicarboxylato)oxovanadate(V) and (4-hydroxypyridine-
,6-dicarboxylato)oxovanadate(V) are recently introduced
by Crans et al. [55]. Oral administration of these compound
is found to be effective in lowering both the hyperglycemia
and hyperlipidemia in rats with streptozotocin (STZ)-in-
duced diabetes (see Fig. 1).
[VO(acac) ] was prepared by the method of K.S. Patel [62].
2
2.2. Preparation of 4-acyl-3-methyl-1-phenyl-2-pyrazolin-5-
one
In view of importance of vanadium compounds, and also
extending the search for more efficacious compounds of
vanadium with neutral charge (one of the desirable qualities
of vanadium compounds to be useful as biomimetic drugs
4-Benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (bmphp)
was prepared by the interaction of 3-methyl-1-phenyl-2-
pyrozoline-5-one in dioxane with calcium hydroxide and
benzoyl chloride by the procedure reported by
Jensen [63]. Following the same procedure, 4-butyryl-3-
methyl-1-phenyl-2-pyrazolin-5-one (bumphp), 4-acetyl-3-
methyl-1-phenyl-2-pyrazolin-5-one (amphp), 3-methyl-1-
phenyl-4-propionyl-2-pyrazolin-5-one (mphpp), and 4-iso-
butyryl-3-methyl-1-phenyl-4-pyrazolin-5-one (iso-bumphp)
were prepared using butyryl chloride, acetyl chloride, pro-
pionyl chloride, and iso-butyryl chloride, respectively.
include neutral charge [4]), we present here the first synthesis
þ
and characterization of VO complexes of aroylhydrazones,
2
0
0
0
0
0
N-(4 -benzoylidene-3 -methyl-1 -phenyl-2 -pyrazolin-5 -one)-
0
isonicotinic acid hydrazide (bmphp-inH), N-(4 -butyrylidene-
0
0 0 0
3
-methyl-1 -phenyl-2 -pyrazolin-5 -one)-isonicotinic acid
0
0
0
hydrazide (bumphp-inH), N-(4 -acetylidene-3 -methyl-1 -
phenyl-2 -pyrazolin-5 -one)-isonicotinic acid hydrazide
0
0
-
O
O
2
.3. Synthesis of aroylhydrazones
O
V
N
O
The aroylhydrazones of isonicotinic acid hydrazide were
O
O
prepared as follows: An ethanolic solution (25 mL) of isoni-
cotinic acid hydrazide (0.685 g, 5 mmol) was added to the
solution (ꢁ25 mL) of bmphp (1.390 g, 5 mmol), bumphp
(1.220 g, 5 mmol), amphp (1.080 g, 5 mmol), mphpp
R
R = H(Pyridine-2,6-dicaboxylato)oxovanadate(V)
R = OH(4-hydroxypyridine-2,6-dicaboxylato)oxovanadate(V)
(1.150 g, 5 mmol) or iso-bumpph (1.220 g, 5 mmol) in etha-
nol. The resulting mixture was refluxed with stirring for 3 h.
A bright orange coloured precipitate was formed while
Fig. 1. Structures of (pyridine/4-hydroxypyridine-2,6-dicarboxylato)-
oxovanadate(V).

R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
135
refluxing. It was filtered and washed several times with eth-
anol and dried in a desiccator over anhydrous CaCl2.
um(V) complexes. Solid states IR spectra were recorded in
KBr pellets using Perkin–Elmer model 1620 FT-IR spectro-
photometer. Electronic spectra were recorded using ATI
Unicam UV-2-100 UV/visible spectrophotometer. Thermo-
gravimetric analysis of the complexes was performed on a
Perkin–Elmer (Pyris Diamond) Thermoanalyser. C, H
and N were determined using Heraeus Carlo Erba 1108 ele-
2
.4. Synthesis of dioxovanadium(V) complexes
A hot methanolic solution (25 mL) of [VO(acac)2]
(0.265 g, 1 mmol) was added to the methanolic solution
(ꢁ25 mL) of the respective Schiff base, bmphp-inH
(0.397 g, 1 mmol), bumphp-inH (0.363 g, 1 mmol), amp-
5
1
mental analyser. The V NMR spectra were recorded in
1
DMSO on a Bruker Mass Spectrometer. The H NMR in
hp-inH (0.335 g, 1 mmol), mphpp-inH (0.349, 1 mmol) or
iso-bumphp-inH (0.363, 1 mmol). The resulting solution
was refluxed for 4 h. It was cooled and filtered. The filtrate
was collected and the residue was dissolved in ethanol–
methanol (1:10) and again filtered. The filtrate thus
obtained is again added to the above filtrate which is then
kept for air oxidation at room temperature for 3–4 days,
with occasional shaking. The resulting compound is col-
lected and recrystallized from methanol.
CDCl was recorded on a Bruker DRX-300, 300 MHz FT
3
NMR, while mass spectrum was recorded over Jeol SX-
102 (FAB). The biological activity test was performed at
Yeast Biotechnology Laboratory in our University.
3. Results and discussion
The dioxovanadium(V) complexes in the present investi-
gation were prepared according to the following equations:
Methanol
2
.5. Analysis
½VOðacacÞ ꢃþLH
!
½VOðLÞðacacÞꢃþacacH
2
Reflux
Ethanol-Methanolð1:10Þ
½
VOðLÞðacacÞꢃ
!
½VOðLÞð H
2
OÞðacacÞꢃꢄH
2
Oþacacꢀ
Carbon, hydrogen and nitrogen were determined micro-
Aerial oxidation
analytically at RSIC, IIT, Bombay. The vanadium content
of the synthesized compounds was determined by the fol-
lowing method.
where LH = bmphp-inH, bumphp-inH, amphp-inH,
mphpp-inH
or
iso-bumphp-inH
and
acacH =
A 100 mg sample of the compound was placed in a silica
crucible, decomposed by gentle heating and then adding 1–
acetylacetone.
These complexes are found to be air stable. They are
thermally stable and their decomposition temperatures
are given in Table 4. These are insoluble in most of the
common organic solvents but are fairly soluble in DMF,
DMSO and acetonitrile. The formulations of these com-
plexes are based on their elemental analysis, infrared spec-
tra, magnetic measurements, ESR, thermogravimetric
analysis and electronic spectral studies.
2
mL of concentrated HNO , 2–3 times. An orange col-
3
oured mass (V O ) was obtained after decomposition and
complete drying. It was dissolved in the minimum amount
of dilute H SO , and the solution so obtained was diluted
with distilled water to 100 mL in a measuring flask. The
vanadium content of each of the complexes was determined
volumetrically [64] using 0.02 M KMnO solution as an oxi-
2
5
2
4
4
dizing agent in the presence of sulfurous acid. Based on the
following redox reactions, the amount of vanadium in the
sample solution was calculated using the standard [64] rela-
3.1. Infrared spectral studies
tionship: 1 mL of 0.02 M KMnO = 0.0051 g vanadium.
The important infrared spectral bands of the ligands as
well as complexes, and their tentative assignments are given
in Tables 1 and 3, respectively. The aroylhydrazones used
in the present investigation may exist in four keto/enol
forms (Fig. 3). The infrared spectra of all the aroylhydraz-
ones exhibit a weak broad band centered at 3400–
4
ꢀ
ꢂ
þ
2þ
2ꢀ
2
VO þ H
2
SO
2þ
4
þ 4H ! 2VO þ SO4 þ 3H
2
O
3
ꢀ
ꢀ
2þ
þ
ꢀ
MnO þ 5VO þ 6H
2
O ! 5 VO þ Mn þ 12H
4
3
*
In aqueous solution V O exists as vanadate ðVO Þ [64].
2
5
3
ꢀ1
ꢀ1
3550 cm for m(OH), a medium band at 1632–1640 cm
2
.6. Molecular modeling studies
for m(C@O) (pyrazolone skeleton) and a strong band due
ꢀ1
to m(C@N) (azomethine) at 1590–1614 cm . Moreover,
the absence of m(NH) and m(C@O) due to isonicotinic acid
hydrazide part of the ligand was observed in the IR spectra
of all the ligands. These two observations suggest that the
ligands under the present investigation exist in the enol
form (I) in the solid state (Fig. 3).
The 3 D molecular modeling of one synthesized com-
pound was carried out on CS Chem 3D Ultra Molecular
Modeling and Analysis Programme [65]. It is an interactive
graphics programme that allows rapid structure building,
geometry optimization and molecular display. It has the
ability to handle transition metal compounds.
These hydrazones possess seven potential donor sites: (i)
1
2
The ring nitrogen N , (ii) the ring nitrogen N , (iii) the
cyclic carbonyl oxygen (pyrazolone skeleton) (iv) the enolic
2
.7. Physical methods
(OH) oxygen (v) the azomethine nitrogen, (vi) the hydra-
The following physical methods were used to determine
the structure of the ligand and their resulting dioxovanadi-
zide nitrogen, and (vii) pyridine ring nitrogen. The coordi-
nation of the ring nitrogen N is unlikely due to possible
1

136
R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
Table 1
Analytical data, colours, melting points, and important IR spectral bands (cm ) and their assignments
ꢀ1
S. no.
Aroylhydrazone
Empirical
Formula)
M. W.)
Analysis, Found (Calc. %)
Colour
M. P. m(C@O) m(C@N)
(pyrazo. (azometh.)
skeleton)
m(–OH) m(N–N) m(C@N)
(amide) (pyrazol.)
skeleton)
(
C
H
N
(
1
2
3
4
5
bmphp-inH
69.30 (69.52) 4.71 (4.79) 17.55 (17.63) Tractor orange 210
66.60 (66.12) 5.66 (5.79) 19.16 (19.28) Tractor orange 240
64.60 (64.48) 5.05 (5.07) 20.46 (20.90) Tractor orange 258
64.97 (65.33) 5.36 (5.44) 20.12 (20.06) Tractor orange 200
66.35 (66.12) 5.70 (5.78) 19.23 (19.28) Bright orange 140
1638
1637
1637
1640
1632
1607
1614
1608
1606
1590
3450
3540
3412
3400
3432
1002
1006
1020
1046
1010
1580
1580
1583
1580
1585
(C
23 19
H N
5
O
2
)(397)
)(363)
)(335)
)(349)
bumphp-inH
(C
20 21
H N
5
O
2
2
2
amphp-inH
(C H N O
18 17 5
mphpp-inH
(C H N O
19 19 5
iso-bumphp-inH
)(363)
20 21 5 2
(C H N O
Table 2
Analytical data and some physical properties of the synthesized complexes
ꢀ
1
S. no.
Complex (Empirical Formula)(M.W.)
Found/calculated (%)
Colour
Decomposition
K
M
2
(ohm
Yield (%)
ꢀ1
temperature (°C) cm mol
in DMF)
)
C
H
N
V
(
1
2
3
4
5
[VO
(
2
(bmphp-in)(H
514.94)
2
O)] Æ H
2
O (C23
H
22
N
5
O
6
V)
V)
V)
V)
53.31 4.19 13.35
9.96 Middle
220
200
225
218
13
45
48
38
40
40
(53.60) (4.27) (13.59) (9.89) buff
49.78 4.86 14.24 10.76 Golden
(49.90) (4.99) (14.55) (10.59) brown
47.46 4.26 15.35 11.50 Tractor
(47.69) (4.42) (15.45) (11.25) orange
48.55 4.64 14.67 10.42 Middle
(48.83) (4.71) (14.99) (10.91) buff
[VO
2
(bumphp-in)(H
2
O)] Æ H
2
O (C20
H
24
N
5
O
6
12.5
17
(480.94)
[VO
2
(amphp-in)(H
2
O)] Æ H
O)] Æ H
(iso-bumphp-in)(H O)] Æ H
2
20 5 6
O (C18H N O
(452.94)
[VO
2
(mphpp-in)(H
2
2
O (C19H
22
N
5
O
6
18.8
20
(466.94)
[VO
2
2
2
O (C20
H
24
N
5
O
6
V) 49.59 4.85 14.37 10.88 Golden yellow 205
(49.90) (4.99) (14.55) (10.59)
(480.94)
Table 3
ꢀ
1
Some important IR spectral bands (cm ) of the synthesized complexes
S. no. Complex (VO as(VO m(C@O) (cyclic carbonyl) m(C@N) (azomethine) d(H O) m(N–N) m(–OH)
m
s
2
)
m
2
)
2
1
2
3
4
5
[VO
[VO
[VO
[VO
[VO
2
2
2
2
2
(bmphp-in)(H
(bumphp-in)(H
(amphp-in)(H O)] Æ H
(mphpp-in)(H O)] Æ H
(iso-bumphp-in)(H
2
O)] Æ H
2
O
944
948
939
972
911
883
892
895
826
829
1560
1570
1565
1576
1560
1586
1592
1579
1590
1576
1629
–
–
1630
1632
1026
1020
1023
1061
1023
3440, 3460
3400–3500
3383
3400
3300–3500
2
O)] Æ H
2
O
2
2
O
O
2
2
2
O)] Æ H
2
O
zwitterion [66] formation due to cyclic amide which reduces
the election density on N . Further, this process increases
The m(C@O) mode of the cyclic carbonyl group observed
1
ꢀ1
at 1632–1640 cm in the ligands is shifted to lower wave
ꢀ
1
the electron density of the cyclic carbonyl oxygen. Coordi-
numbers and appears at 1560–1576 cm in these complex-
es. This suggests the bonding of the cyclic carbonyl oxygen
[67] to vanadium in all these complexes. The aroylhydraz-
ones under discussion display a sharp and strong band
due to m(C@N) of the azomethine group at 1590–
1
nation of N is also unfavourable because of the greater
steric demand of the phenyl ring.
2
The ring nitrogen N in this ligand is found to be inert
towards coordination to vanadium as revealed by the
2
ꢀ1
appearance of the m(C@N ) (cyclic) mode at almost the
1614 cm . The observed low energy shift of this band in
ꢀ
1
same position [here merged with m(C@N) (azomethine)]
the complexes at 1576–1592 cm suggests the coordina-
tion of the azomethine nitrogen to vanadium. This is fur-
ther supported by shifting [68,69] of the m(N–N) from
2
ꢀ1
compared with the m(C@N ) (cyclic) at 1580–1585 cm
of the uncoordinated ligand, after complexation. The
ꢀ1
ꢀ1
band due to m(C@O) (hydrazide moiety) at approximately
1002–1046 cm
to 1020–1061 cm
in the complexes.
ꢀ
1
1
670 cm is absent in all the complexes indicating the
The coordination of azomethine nitrogen, cyclic ring car-
bonyl oxygen and enolic oxygen as concluded from the
above discussions is favourable in the light of one 5-mem-
bered and one 6-membered chelate rings with the central
enolization of the carbonyl group. Instead, a new band
ꢀ
1
appears at 1106–1163 cm due to coordination of m(C–
O enolic).

R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
137
X
4
1
N
H
N
3.2. Conductance measurements
OH
X
N
O
N
H C
N
3
H C
3
The
observed
molar
conductances
molar DMF solutions of
(12.5–
3
5
ꢀ1
2
ꢀ1
ꢀ3
2
O
20 ohm cm mol ) in 10
N
OH
N
N
N
N
these complexes are given in Table 2, and are consistent
with the non-electrolytic nature of the complexes. Such a
non-zero molar conductance value for each of the complex
in the present study is most probably due to the strong
donor capacity of DMF, which may lead to the displace-
ment of anionic ligand and change of electrolyte [70] type.
[I]
[II]
H
N
X
X
O
OH
N
N
N
H C
H C
3
3
5
.3. V NMR spectra
1
3
N
O
N
OH
N
N
N
N
5
1
The V NMR spectra of two representative compounds
VO (bumphp-in)(H O)] Æ H O and [VO (bmphp-in)(H O)]
[
2
2
2
2
2
(
Figs. 4 and 5) were recorded in DMSO-d . The complexes
[III]
[IV]
6
exhibit a strong resonance at ca. ꢀ508.81 and ꢀ508.96,
respectively, as expected for the dioxovanadium(V) com-
plexes having a mixed O/N donor set [12].
Fig. 3. Different keto-enol forms of the aroylhydrazones.
1
3.4. H NMR spectra
metal vanadium. In view of this, the coordination of hydra-
zide nitrogen and pyridine ring nitrogen is ruled out. The
overall IR spectral studies conclude that the aroylhydraz-
ones used in the present study behave as monobasic triden-
tate ONO-ligands.
The metal complexes also show two medium bands or
one broad band (see Table 2) due to m(OH) because of
the presence of lattice/coordinated water in them.
Proton NMR spectrum of one representative compound,
[VO (bumphp-in)(H O)] Æ H O was recorded in CDCl . The
2
2
2
3
absence of the enolic (–OH) proton signals at approximately
12 ppm and the hydrazone (–NH) proton signal at approx-
imately 11 ppm in the complex indicates the coordination of
enolic oxygen to the metal ion after deprotonation. The
51
2 2 2
Fig. 4. V NMR spectrum of compound [VO (bumphp-in)(H O)] Æ H O.

138
R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
51
2 2 2
Fig. 5. V NMR spectrum of compound [VO (bmphp-in)(H O)] Æ H O.
2 2 2
Fig. 6. Mass spectrum of [VO (bumphp-in)(H O)] Æ H O.
proton signals due to aromatic protons of the ligand in the
complex compound appeared at 7.2–7.9 ppm. The two pro-
ton signals at 1.5–1.6 ppm and 2.4 ppm may be due to
butyryl and methyl group, respectively, present in the ligand.
sistent with the molecular mass of the present compound
excluding two water molecules present therein, which are
supposed to be lost before ionization. This confirms the
formula weight, and hence the molecular composition of
the synthesized compound.
3
.5. Mass spectral studies
3.6. Electronic spectral studies
The mass spectrum (Fig. 6) of one representative com-
pound, [VO (bumphp-in)-(H O)] Æ H O was recorded. The
appearance of a molecular ion peak at 446.1634 m/z is con-
The electronic spectra of 4 compounds, namely, 1, 2, 3
and 4 were recorded in 10 M DMF solution and their
2
2
2
ꢀ
4

R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
139
Table 4
Electronic spectral data of the synthesized complexes
ꢀ1
ꢀ1
ꢀ1
)
Compound no.
Compound
kMax (nm)
m (cm
)
(e, L cm mol
Peak assignment
1
[VO
2
(bmphp-in)(H
2
O)] Æ H
2
O
293
34,129
32,258
28,011
27,397
24,096
34,700
34,370
36,460
36,290
28,980
Intra-ligand transitions
3
3
3
4
10
57
65
15
LMCT
2
3
4
[VO
[VO
[VO
2
2
2
(bumphp-in)(H
2
O)] Æ H
2
O
255
39,215
35,971
27,397
25,062
9900
33,090
35,870
27,760
Intra-ligand transitions
2
3
3
78
65
99
LMCT
(amphp-in)(H
2
O)] Æ H
2
O
254
39,370
36,496
27,174
25,641
9460
28,540
23,900
24,590
Intra-ligand transitions
2
3
3
74
68
90
LMCT
(mphpp-in)(H
2
O)] Æ H
2
O
256
39,062
34,965
28,248
27,397
24,096
9910
33,490
35,380
35,600
28,200
Intra-ligand transitions
2
3
3
4
86
54
65
15
LMCT
Ref. [68]
Ref. [71]
[VO
2
(acpy-bhz)(DMF)]
236
42,372
36,496
25,477
4703
18,999
22,041
Intra-ligand transitions
2
3
74
92.5
LMCT
K[VO
2
(Clsal-iNH)(H
2
O] (methanol)
235
42,553
35,842
31,595
24,360
20,730
10,085
9600
Intra-ligand transitions
2
3
4
79
16.5
10.5
6100
LMCT
.
[VO (bumphp-in)( H O)] H O
2 2 2
results are shown in the Table 4. All the complexes dis-
played three to four intra-ligand transitions in the UV
region, which were present in the ligands at some higher
66 ºC
[VO (bumphp-in)( H O)]
-H O (Lattice)
2
0
wavelengths. Dioxovanadium(V) complexes have a 3d
configuration, and d–d bands are therefore not expected.
The additional one spectral peak at 390–415 nm in all the
complexes is due to ligand to metal charge transfer (LMCT)
transitions. These results are comparable to the data reported
elsewhere [68,71], for dioxovanadium(V) compounds.
2
2
1
30 ºC
-H O (Coordinated)
2
[
VO (bumphp-in)]
2
5
80 ºC
3
.7. Thermogravimetric analysis
V O (Residue)
2
5
The TG curve of
a
representative compound
[
VO (bumphp-in)(H O)] Æ H O (2) shows a weight loss of
2
2
2
3
.41% at 66 °C corresponding to the loss of one lattice
was carried out in vitro at 0.2 mmol concentration against
fungi Aspergillus flavus and yeast Saccharomyces cerevisiae
in 250 mL conical flasks with 100 mL volumes of a sterile
water molecule (calcd. 3.74%) from the complex. The sec-
ond weight loss at 130 °C was observed to be 3.63% (calcd.
3
.89%) corresponding to the elimination of one coordinat-
ed water molecule. It shows a final weight loss between 395
and 469 °C leaving to a constant value corresponding to
the residual mass of V O at 580 °C (40.68%) which match-
Table 5(a)
Biological activity against yeast
2
5
es the theoretical value (40.87%). The following equations
represent the above decomposition steps:
S. no. Flask
OD on 5th
day (at 660 nm ) 5th day 7th day
at 660 nm )
I% on
OD on
I% on
7th day
a
a
(
3
.8. Biological activity
1
2
3
Control
Ligand
Complex 1.822
2.500
2.500
0
0
3.163
0.748
0.269
0
76.35
91.50
27.12
Determination of the biological activity of ligand,
a
bumphp-inH and compound, [VO (bumphp-in)(H O)] (2)
kmax for yeast.
2
2

140
R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
Table 5(b)
Biological activity against fungi
NDM [72] medium containing (w/v, %): (NH ) SO (0.25),
4 2 4
yeast extract (0.25), KH PO (0.5), MgSO Æ 7H O (0.05),
2
4
4
2
S. no. Flask
Culture weight I% on
on 5th day 5th day on 7th day
in g)
Culture weight I% on
CaCl Æ 2H O (0.013) and glucose (2). The biological activ-
2 2
ity was enhanced against yeast and reduced against fungi
after complexation. The amount of growth inhibition
7th day
(
(in g)
1
2
3
Control
Ligand
Complex 0.24
0.30
0.22
0
0.388
0.148
0.317
0
(Tables 5(a) and 5(b)) was determined by the following
26.66
20
61.85
18.29
expression:
I% ¼ ðC-TÞ=C ꢅ 100
where, I, inhibition; C, growth of control plates; T, growth
R
-
O
K+
O
of treated plates.
O
V
N
OH2
3.8.1. Yeast
O
R= H (a); R = Cl (b)
The greater toxicity of the metal complex compared to
the free ligand can be explained on the basis of chelation
theory. Chelation reduces the polarity of the metal ion
mainly because of partial sharing of its positive charge with
the donor groups and possible p-electron delocalization
over the whole chelate ring. This increases the lipophilic
N
N
Fig. 7. Structures of K[VO
O)].
2
(sal-iNH)(H
2 2
O)] and K[VO (Clsal-iNH)
(H
2
2 2 2
Fig. 8. 3D structure of compound [VO (amphp-in)(H O)] Æ H O (3).

R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
141
Table 6
Various bond lengths of compound [VO
Table 7
2
(amphp-in)(H
2
2
O)] Æ H O (3)
2 2 2
Various bond angles of compound [VO (amphp-in)(H O)] Æ H O (3)
S. no. Atoms Actual bond length Optimal bond length
S. no.
Atoms
Actual bond
angles
Optimal bond
angles
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
V(1)–O(2)
V(1)–O(3)
V(1)–O(5)
V(1)–N(7)
V(1)–O(13)
V(1)–O(27)
C(4)–O(5)
C(4)–N(6)
C(4)–C(37)
N(6)–N(7)
2.013
1.655
2.009
1.906
1.882
2.006
1.505
2.543
1.854
1.496
2.81
2.013
1.655
2.009
1.906
1.882
2.006
1.505
2.543
1.854
1.496
2.81
1.426
1.47
1.462
1.26
1.409
1.497
1.174
1.866
1.47
1.402
1.113
1.113
1.113
1.751
1.113
1.113
1.113
1.42
1.42
1.1
1.42
1.1
1.42
1.1
1.42
1.42
1.1
1.1
–
–
1.42
1.42
1.1
1.358
1.1
1.358
1.42
1.1
1.42
1.1
1
2
3
4
5
6
7
8
9
O(2)–V(1)–O(3)
O(2)–V(1)–O(5)
O(2)–V(1)–N(7)
O(2)–V(1)–O(13)
O(2)–V(1)–O(27)
O(3)–V(1)–O(5)
97.842
98.965
105.165
89.782
157.728
87.991
153.078
77.121
72.172
124.396
101.719
113.233
124.84
89.322
109.002
109.003
108.818
119.998
119.998
120
O(3)–V(1)–N(7)
O(3)–V(1)–O(13)
O(3)–V(1)–O(27)
O(5)–V(1)–N(7)
O(5)–V(1)–O(13)
O(5)–V(1)–O(27)
N(7)–V(1)–O(13)
N(7)–V(1)–O(27)
O(13)–V(1)–O(27)
O(5)–C(4)–N(6)
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
5
5
68.067
N(7)–C(15)
N(8)–N(9)
10
11
12
13
13
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
101.803
163.676
64.571
89.026
93.359
103.009
106.772
99.995
153.213
108.849
89.679
1.426
1.47
1.462
1.26
N(8)–C(12)
N(8)–C(24)
N(9)–C(10)
C(10)–C(11)
C(10)–C(14)
C(11)–C(12)
C(11)–C(15)
C(11)–H(63)
C(12)–O(13)
C(14)–H(54)
C(14)–H(55)
C(14)–H(56)
C(15)–C(16)
C(16)–H(17)
C(16)–H(18)
C(16)–H(19)
C(21)–C(22)
C(21)–C(26)
C(21)–H(62)
C(22)–C(23)
C(22)–H(61)
C(23)–C(24)
C(23)–H(66)
C(24)–C(25)
C(25)–C(26)
C(25)–H(65)
C(26)–H(64)
120.005
119.996
119.998
120.001
120.003
119.995
120.001
120.003
119.995
120.007
119.996
119.996
119.998
120.005
119.995
112.745
116.651
109.524
106.536
100.145
152.281
116.994
117.772
123.845
122.628
120.606
117.942
121.446
122.329
111.609
123.95
67.357
158.646
129.027
108.8
108.8
109.51
110
110
110
109
109
109
120
120
120
120
120
120
120
1.409
1.497
1.174
1.866
1.47
1.402
1.113
1.113
1.113
1.751
1.113
1.113
1.113
1.42
1.42
1.1
1.42
1.1
1.42
1.1
1.42
1.42
O(5)–C(4)–C(37)
N(6)–C(4)–C(37)
V(1)–O(5)–C(4)
C(4)–N(6)–N(7)
V(1)–N(7)–N(6)
V(1)–N(7)–C(15)
N(6)–N(7)–C(15)
N(9)–N(8)–C(12)
N(9)–N(8)–C(24)
C(12)–N(8)–C(24)
N(8)–N(9)–C(10)
N(9)–C(10)–C(11)
N(9)–C(10)–C(14)
C(11)–C(10)–(14)
C(10)–C(11)–(12)
C(10)–C(11)–(15)
C(10)–C(11)–(63)
C(12)–C(11)–(15)
C(12)–C(11)–(63)
C(15)–C(11)–(63)
N(8)–C(12)–C(11)
N(8)–C(12)–O(13)
C(11)–C(12)–(13)
V(1)–O(13)–C(12)
C(10)–C(14)–(54)
C(10)–C(14)–(55)
C(10)–C(14)–(56)
H(54)–C(14)–(55)
H(54)–C(14)–(56)
H(55)–C(14)–(56)
N(7)–C(15)–C(11)
N(7)–C(15)–C(16)
C(11)–C(15)–C(16)
C(15)–C(16)–H(17)
C(15)–C(16)–H(18)
C(15)–C(16)–H(19)
H(17)–C(16)–H(18)
H(17)–C(16)–H(19)
H(18)–C(16)–H(19)
C(22)–C(21)–C(26)
C(22)–C(21)–H(62)
C(26)–C(21)–H(62)
C(21)–C(22)–C(23)
C(21)–C(22)–H(61)
C(23)–C(22)–H(61)
C(22)–C(23)–C(24)
119.209
80.806
149.907
110.997
124.504
124.497
104.501
105.001
122.603
132.381
123.032
119.662
123.476
110.446
89.089
79.922
96.458
1.1
1.1
110.502
115.218
110.54
109.998
109.989
109.995
109.005
109.002
108.823
72.172
O(27)–H(28) 1.078
O(27)–H(29) 0.952
C(32)–C(33)
C(32)–C(37)
C(32)–H(51)
C(33)–N(34)
C(33)–H(50)
N(34)–C(35)
C(35)–C(36)
C(35)–H(49)
C(36)–C(37)
C(36)–H(48)
1.316
1.443
1.2
1.531
1.197
1.382
0.943
1.301
1.437
0.921
124.396
101.719
113.233
124.84
5
5
5
5
5
5
5
5
5
1
2
3
4
5
6
7
8
9
89.322
109.002
109.003
108.818
119.998
119.998
120
120.005
119.996
119.998
120.001
character of the metal complex, which subsequently
favours its permeation through the lipoid layers of organ-
ism cell membrane. Furthermore, the mode of action of
compounds may involve the formation of a hydrogen bond
through the >C@N (azomethine group) with the active
centres of the cell constituents resulting in an interference
with the normal cell process.
60
61
6
2
(
continued on next page)

142
R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
Table 7 (continued)
Table 8
2 2 2
Various dihedral angles of compound [VO (amphp-in)(H O)] Æ H O (3)
S. no.
Atoms
Actual bond
angles
Optimal bond
angles
S. no.
Atoms
Actual bond
angles
Optimal bond
angles
6
6
6
6
6
6
6
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
9
9
9
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
C(22)–C(23)–H(66)
C(24)–C(23)–H(66)
N(8)–C(24)–C(23)
N(8)–C(24)–C(25)
C(23)–C(24)–C(25)
C(24)–C(25)–C(26)
C(24)–C(25)–H(65)
C(26)–C(25)–H(65)
C(21)–C(26)–C(25)
C(21)–C(26)–H(64)
C(25)–C(26)–H(64)
V(1)–O(27)–H(28)
V(1)–O(27)–H(29)
H(28)–O(27)–H(29)
C(33)–C(32)–C(37)
C(33)–C(32)–H(51)
C(37)–C(32)–H(51)
C(32)–C(33)–N(34)
C(32)–C(33)–H(50)
N(34)–C(33)–H(50)
C(33)–N(34)–C(35)
N(34)–C(35)–C(36)
N(34)–C(35)–H(49)
C(36)–C(35)–H(49)
C(35)–C(36)–C(37)
C(35)–C(36)–H(48)
C(37)–C(36)–H(48)
C(4)–C(37)–C(32)
C(4)–C(37)–C(36)
C(32)–C(37)–C(36)
120.003
119.995
120.001
120.003
119.995
120.007
119.996
119.996
119.998
120.005
119.995
112.745
116.651
109.524
106.536
100.145
152.281
116.994
117.772
123.845
122.628
120.606
117.942
121.446
122.329
111.609
123.95
120
120
120
120
120
120
120
120
120
120
120
–
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
O(2)–V(1)–O(5)–C(4)
O(3)–V(1)–O(5)–C(4)
N(7)–V(1)–O(5)–C(4)
O(13)–V(1)–O(5)–C(4)
O(27)–V(1)–O(5)–C(4)
O(2)–V(1)–N(7)–N(6)
O(2)–V(1)–N(7)–C(15)
O(3)–V(1)–N(7)–N(6)
O(3)–V(1)–N(7)–C(15)
O(5)–V(1)–N(7)–N(6)
O(5)–V(1)–N(7)–C(15)
O(13)–V(1)–N(7)–N(6)
O(13)–V(1)–N(7)–C(15)
O(27)–V(1)–N(7)–N(6)
O(27)–V(1)–N(7)–C(15)
O(2)–V(1)–O(13)–C(12)
O(3)–V(1)–O(13)–C(12)
O(5)–V(1)–O(13)–C(12)
N(7)–V(1)–O(13)–C(12)
O(27)–V(1)–O(13)–(12)
O(2)–V(1)–O(27)–H(28)
O(2)–V(1)–O(27)–H(29)
O(3)–V(1)–O(27)–H(28)
O(3)–V(1)–O(27)–H(29)
O(5)–V(1)–O(27)–H(28)
O(5)–V(1)–O(27)–H(29)
N(7)–V(1)–O(27)–H(28)
N(7)–V(1)–O(27)–H(29)
O(13)–V(1)–O(27)–(28)
O(13)–V(1)–O(27)–(29)
N(6)–C(4)–O(5)–V(1)
C(37)–C(4)–O(5)–V(1)
O(5)–C(4)–N(6)–N(7)
C(37)–C(4)–N(6)–N(7)
O(5)–C(4)–C(37)–C(32)
O(5)–C(4)–C(37)–C(36)
N(6)–C(4)–C(37)–C(32)
N(6)–C(4)–C(37)–C(36)
C(4)–N(6)–N(7)–V(1)
C(4)–N(6)–N(7)–C(15)
V(1)–N(7)–C(15)–C(11)
V(1)–N(7)–C(15)–C(16)
N(6)–N(7)–C(15)–C(11)
N(6)–N(7)–C(15)–C(16)
C(12)–N(8)–N(9)–C(10)
C(24)–N(8)–N(9)–C(10)
N(9)–N(8)–C(12)–C(11)
N(9)–N(8)–C(12)–O(13)
C(24)–N(8)–C(12)–C(11)
C(24)–N(8)–C(12)–O(13)
N(9)–N(8)–C(24)–C(23)
N(9)–N(8)–C(24)–C(25)
C(12)–N(8)–C(24)–C(23)
C(12)–N(8)–C(24)–C(25)
N(8)–N(9)–C(10)–C(11)
N(8)–N(9)–C(10)–C(14)
N(9)–C(10)–C(11)–C(12)
N(9)–C(10)–C(11)–C(15)
N(9)–C(10)–C(11)–H(63)
C(14)–C(10)–C(11)–(12)
C(14)–C(10)–C(11)–(15)
C(14)–C(10)–C(11)–(63)
N(9)–C(10)–C(14)–H(54)
ꢀ120.71
141.664
ꢀ13.041
117.634
75.066
143.044
ꢀ12.971
ꢀ69.172
134.813
40.244
ꢀ15.772
ꢀ27.447
76.538
ꢀ24.471
179.553
24.49
122.589
147.266
ꢀ80.681
ꢀ73.909
36.707
ꢀ91.308
ꢀ16.779
ꢀ44.796
81.824
ꢀ46.193
ꢀ76.694
55.285
ꢀ86.923
145.061
ꢀ4.555
176.517
25.623
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
120
120
120
123.5
120
116.5
115
123.5
116.5
120
120
120
120
121.4
121.4
120
67.357
158.646
129.027
30
31
32
33
34
35
3
.8.2. Fungi
The >C@N groups in the ligand are free and, therefore,
ꢀ56.738
ꢀ56.969
59.244
the ligand shows higher toxicity as it can easily combine
with the fungi cells to check growth. On the other hand,
in metal complex, this group is not free to inhibit cell
growth, as they are involved in bond formation with the
metal ions. Hence, the toxicity of metal complex decreases.
36
37
25.324
38
39
40
41
42
ꢀ18.465
ꢀ36.612
90.233
ꢀ83.254
ꢀ75.456
141.785
49.583
3
.9. 3D Molecular modeling and analysis
43
44
45
46
47
0.448
In view the monomeric hexa-coordination of all the
ꢀ79.105
complexes, and also the well established octahedral struc-
ture [11] of dioxovanadium(V) complexes, K[VO (sal-
iNH)(H O)] (a) and K[VO (Clsal-iNH)(H O)] (b) (Fig. 7)
involving
donor) ligand (similar to ONO donor aroylhydrazone
ligands in the present investigation), the 3D molecular
modeling of one of the representative compounds, viz.,
0.316
2
48
49
ꢀ119.715
179.684
59.775
ꢀ60.576
118.844
120.001
ꢀ60.576
ꢀ0.838
ꢀ179.684
1.266
2
2
2
50
51
52
53
N-isonicotinamido-salicylaldimines
(ONO
54
55
[
VO (amphp-in)(H O)] cdot H O (3), was carried out with
2 2 2
56
57
58
59
the CS Chem 3D Ultra Molecular Modeling and Analysis
Programme [65] based on its octahedral structure. The
details of bond lengths, bond angles and dihedral angles
as per the 3D structure (Fig. 8), are given in Tables 6–8,
respectively. For convenience of looking over the different
bond lengths and bond angles, the various atoms in the
compound in question are numbered in Arabic numerals.
ꢀ146.894
115.336
180
60
61
31.767
6
6
2
3
ꢀ66.003
ꢀ119.998

R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
143
Table 8 (continued)
Table 8 (continued)
S. no.
Atoms
Actual bond
angles
Optimal bond
angles
S. no.
Atoms
Actual bond
angles
Optimal bond
angles
6
6
6
6
6
6
7
7
7
7
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
9
9
9
9
9
9
9
9
9
9
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
0
1
2
3
4
5
6
7
8
9
N(9)–C(10)–C(14)–H(55)
N(9)–C(10)–C(14)–H(56)
C(11)–C(10)–C(14)–(54)
C(11)–C(10)–C(14)–(55)
C(11)–C(10)–C(14)–(56)
C(10)–C(11)–C(12)–N(8)
C(10)–C(11)–C(12)–(13)
C(15)–C(11)–C(12)–N(8)
C(15)–C(11)–C(12)–(13)
H(63)–C(11)–C(12)–N(8)
H(63)–C(11)–C(12)–(13)
C(10)–C(11)–C(15)–N(7)
C(10)–C(11)–C(15)–(16)
C(12)–C(11)–C(15)–N(7)
C(12)–C(11)–C(15)–(16)
H(63)–C(11)–C(15)–N(7)
H(63)–C(11)–C(15)–(16)
N(8)–C(12)–O(13)–V(1)
C(11)–C(12)–O(13)–V(1)
N(7)–C(15)–C(16)–H(17)
N(7)–C(15)–C(16)–H(18)
N(7)–C(15)–C(16)–H(19)
C(11)–C(15)–C(16)–(17)
C(11)–C(15)–C(16)–(18)
C(11)–C(15)–C(16)–(19)
C(26)–C(21)–C(22)–(23)
C(26)–C(21)–C(22)–(61)
H(62)–C(21)–C(22)–(23)
H(62)–C(21)–C(22)–(61)
C(22)–C(21)–C(26)–(25)
C(22)–C(21)–C(26)–(64)
H(62)–C(21)—C(26)–(25)
H(62)–C(21)–C(26)–(64)
C(21)–C(22)–C(23)–(24)
C(21)–C(22)–C(23)–(66)
H(61)–C(22)–C(23)–(24)
H(61)–C(22)–C(23)–(66)
C(22)–C(23)–C(24)–(8)
C(22)–C(23)–C(24)–(25)
H(66)–C(23)–C(24)–(8)
H(66)–C(23)–C(24)–(25)
N(8)–C(24)–C(25)–(26)
N(8)–C(24)–C(25)–(65)
C(23)–C(24)–C(25)–(26)
C(23)–C(24)–C(25)–(65)
C(24)–C(25)–C(26)–(21)
C(24)–C(25)–C(26)–(64)
H(65)–C(25)–C(26)–(21)
H(65)–C(25)–C(26)–(64)
C(37)–C(32)–C(33)–(34)
C(37)–C(32)–C(33)–(50)
H(51)–C(32)–C(33)–(34)
H(51)–C(32)–C(33)–(50)
C(33)–C(32)–C(37)–C(4)
C(33)–C(32)–C(37)–(36)
H(51)–C(32)–C(37)–C(4)
H(51)–C(32)–C(37)–(36)
C(32)–C(33)–N(34)–(35)
H(50)–C(33)–N(34)–(35)
C(33)–N(34)–C(35)–(36)
C(33)–N(34)–C(35)–(49)
N(34)–C(35)–C(36)–(37)
N(34)–C(35)–C(36)–(48)
H(49)–C(35)–C(36)–(37)
119.926
0
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
128
129
130
131
132
H(49)–C(35)–C(36)–(48)
C(35)–C(36)–C(37)–C(4)
C(35)–C(36)–C(37)–(32)
H(48)–C(36)–C(37)–C(4)
H(48)–C(36)–C(37)–(32)
ꢀ2.686
120.699
ꢀ14.728
ꢀ41.374
ꢀ176.787
–
–
–
–
61.536
ꢀ58.539
ꢀ178.387
ꢀ0.895
115.359
149.81
ꢀ93.898
ꢀ131.299
ꢀ15.009
ꢀ121.477
1.142
86.657
ꢀ150.707
1.45
124.081
ꢀ179
N
X =
-C H
6 5
N
O
O
N
O
-C H
3
7
-CH3
H C
V
3
-C H
2
5
OH2
O
-iso-C3H7
X
N
72.171
ꢀ135.92
87.155
ꢀ25.474
147.784
10.857
ꢀ101.771
0
N
Fig. 9. Proposed structures of the complexes.
In all, 275 measurements of the bond lengths, plus the bond
angles including dihedral angles are listed in the tables.
Except few cases, optimal values (most favourable) of both
the bond lengths and the bond angles are given in the tables
along with the actual ones. In most of the cases, the
observed bond lengths and bond angles are close to the
optimal values, and thus the proposed structure of com-
pound 3 as well as of the others, are acceptable.
ꢀ179.451
ꢀ179.451
1.142
0
179.451
179.451
ꢀ1.184
0
ꢀ79.451
179.451
0
179.451
0
ꢀ1.184
179.451
ꢀ79.368
1.184
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
4. Conclusion
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
The satisfactory analytical data coupled with the studies
presented above suggest that the dioxovanadium(V) com-
plexes synthesized in this investigation are of the general
composition. [VO (L)(H O)] Æ H O, where LH = N-(4 -ben-
zoylidene-3 -methyl-1 -phenyl-2 -pyrazolin-5 -one)-isonicot-
0
2
2
2
0 0 0 0
0
ꢀ79.368
0
0
0
inic acid hydrazide, N-(4 -butyrylidene-3 -methyl-1 -phenyl-
0
0
0
0
2
-pyrazolin-5 -one)-isonicotinic acid hydrazide, N-(4 -
ꢀ79.451
179.451
0
0
0
0
0
acetylidene-3 -methyl-1 -phenyl-2 -pyrazolin-5 -one)-isoni-
cotinic acid hydrazide, N-(3 -methyl-1 -phenyl-4 -prop-
ionylidene-2 -pyrazolin-5 -one)-isonicotinic acid hydrazide
0
0
0
0
0
ꢀ8.297
ꢀ175.391
179.292
12.217
ꢀ152.566
11.357
11.178
175.094
8.701
174.925
ꢀ10.764
168.516
12.526
176.575
ꢀ166.729
0
0
0
0
or N-(4 -iso-butyrylidene-3 -methyl-1 -phenyl-2 -pyrazolin-
0
5
-one)-isonicotinic acid hydrazide. Keeping in view the
monomeric hexa-coordination of all the complexes, and
the well established octahedral structure [11] of dioxovana-
dium(V) complexes, K[VO (sal-iNH)(H O)] and K[VO
2
2
2
(Clsal-iNH)(H O)] involving N-isonicotinamido-salicylaldi-
2
mines (aroylhydrazones) ligand (similar to LH in the present
investigation), octahedral structures (Fig. 9) with cis-dioxo
group have been proposed for these complexes. X-ray crys-
tallographic studies, which might confirm the proposed
structures, could not be carried out as suitable crystals were
not obtained.

1
44
R.C. Maurya, S. Rajput / Journal of Molecular Structure 833 (2007) 133–144
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