H.H. Monfared et al. / Inorganica Chimica Acta 363 (2010) 2574–2583
2575
1562 (vs), 1469 (s), 1362 (s), 1262 (vs), 1231 (s), 1100 (m), 977
(w), 892 (w), 731 (m), 623 (m), 515 (w), 477 (w). UV–Vis spectrum
HO
in CH3OH [kmax, (e
, Mꢁ1 cmꢁ1)]: 225 (59 850), 290sh (27 200),
X
N
313 nm (36 250). 1H NMR DMSO-d6 (ppm): 12.123 (1H, s) (N–H),
11.250 (1H, s) (aryl-OH), 10.866 (naphthyl-OH), 8.672 (1H, s) (azo-
methine), 8.473 (1H, s) (naphthyl-3-H), 6.837–7.915 (8H, m) (aro-
matic), 3.812 (3H, s) (OCH3).
N
O
O
V
O
OCH3
Y
2.1.2. (E)-3-hydroxy-N0-(2-hydroxybenzylidene)-2-naphthohydrazide
(1): X = H, Y = OCH3
(H2L2)
2
(
): X = H, Y = H
Yield 0.475 g (95%). Mp (dp) 317 °C. Anal. Calc. for C18H14N2O3
(MW = 306.32): C, 70.58; H, 4.61; N, 9.15. Found: C, 70.57; H,
(3): X = Br, Y = H
4.64; N, 9.18%. IR (KBr, cmꢁ1): 3469 (w, br) (
m
O–H), 3346 (w, br,
Fig. 1. Structural formulae of methoxylatooxovanadium(V) complexes with depro-
tonated 1:1 condensation products of 3-hydroxy-2-naphthohydrazide with salicyl-
aldehyde and its derivatives.
ꢀ
ꢀ
m
ꢀ
m
O–H), 3192 (vs) (
(m, br), 1653 (vs) (
1362 (s), 1277 (vs), 1223 (s), 1169 (m), 1077 (m), 762 (s), 646
N–H), 3031 (vs, vbr), 2669 (m), 2546 (m), 2392
ꢀ
m
ꢀ
m
C@O), 1631 (s) (
C@N), 1561 (vs), 1453 (s),
(m), 477 (s). UV–Vis spectrum in CH3OH [kmax, (
e
, Mꢁ1 cmꢁ1)]:
oxidation catalysis and as part of our research in the study of coor-
dinating capabilities of aroylhydrazones and their coordination
compounds [27–31] we report here the synthesis, characterization
and efficiency in mediated hydrocarbon oxidation of a series of
methoxylato oxovanadium(V) complexes comprising coordinated
single condensation products of 3-hydroxy-2-naphthohydrazide
with aromatic o-hydroxybenzaldehydes along with the X-ray
structure analysis carried out on two complexes. Structural formu-
lae of the synthesized catalysts are displayed in Fig. 1.
237 (62 000), 286 (17 900), 306sh (13600), 338 nm (12800). 1H
NMR DMSO-d6 (ppm): 12.140 (1H, s) (N-H), 11.211 (2H, s) (OH),
8.667 (1H, s) (azomethine), 8.445 (1H, s) (naphthyl-3-H), 6.894-
7.917 (9H, m) (aromatic).
2.1.3. (E)-N0-(5-bromo-2-hydroxybenzylidene)-3-hydroxy-2-
naphthohydrazide (H2L3)
Yield 0.60 g (96%). Mp (dp) 336 °C. Anal. Calc. for C18H13BrN2O3
(MW = 385.21): C, 56.12; H, 3.40; N, 7.27. Found: C, 56.10; H, 3.45;
N, 7.30%. IR (KBr, cmꢁ1): 3662 (w, br) (
m
O–H), 3189 (s, vbr) (
m
N–H),
ꢀ
ꢀ
2. Experimental
ꢀ
ꢀ
m
3062 (m, br), 1647 (vs) (
m
C@O), 1625 (m) (
C@N),1552 (s), 1520
(m),1472 (m), 1352 (s), 1268 (vs), 1115 (m), 940 (w), 868 (w),
Vanadium(IV) oxide acetylacetonate ([VO(acac)2]), olefins, sol-
vents and other materials were purchased in the highest possible
purity from Merck and Fluka and used as received. Melting points
were recorded on an Electrothermal 9100 apparatus (up to 300 °C).
IR spectra were recorded in KBr disks with a Matson 1000 FT-IR
spectrophotometer. UV–Vis spectra of solution were recorded on
a Shimadzu 160 spectrometer. 1H NMR spectra of ligands in
DMSO-d6 solution were recorded on a Bruker 250 MHz spectrom-
eter and chemical shifts are indicated in ppm relative to tetrameth-
ylsilane. The reaction products of oxidation were determined and
analyzed by HP Agilent 6890 gas chromatograph equipped with a
740 (s), 629 (s), 468 (m). UV–Vis spectrum in CH3OH [kmax, (e,
Mꢁ1 cmꢁ1)]: 231 (34 350), 287 (10 800), 296sh (10 200), 308 (10
100) 346 nm (7 750). 1H NMR DMSO-d6 (ppm): 11.953 (1H, s)
(N–H), 11.257 (2H, s) (OH), 8.611 (1H, s) (azomethine), 8.419
(1H, s) (naphthohydrazide 3-H), 6.678-7.907 (8H, m) (aromatic).
2.2. Synthesis of the complexes [VVO(OCH3)(L)] (1–3)
These complexes were synthesized by the same general meth-
od. General procedure: The appropriate ligand (H2L1, H2L2, or
H2L3) (1.2 mmol) was dissolved in methanol (10 ml). [VO(acac)2]
(0.24 g, 1.2 mmol) was added and the solution was gently refluxed
for 4 h. After cooling, the resulting solid was filtered off, washed
with cooled absolute ethanol, recrystallized from methanol/etha-
nol (50:50 v/v) and then dried at 100 °C.
HP-5 capillary column (phenyl methyl siloxane 30
l
m ꢀ 320
l
m ꢀ
0.25 m) and gas chromatograph–mass spectrometry (Hewlett-
l
Packard 5973 Series MS-HP gas chromatograph with a mass-selec-
tive detector). The elemental analyses (carbon, hydrogen, and
nitrogen) of compounds were obtained from Carlo ERBA Model
EA 1108 analyzer. Vanadium percentages of complexes were mea-
sured by a Varian spectrometer AAS-110.
2.2.1. [Vvo(och3)(l1)] (1)
Yield 0.44 g (85%). Anal. Calc. for C20H17N2O6V (MW = 432.30):
C, 55.57; H, 3.96; N, 6.48; V, 11.78. Found: C, 55.55; H, 3.96; N,
2.1. Synthesis of H2L1–3 ligands
6.46; V, 11.81%. IR (KBr, cmꢁ1): 3422 (w, br) (
m
O–H), 2967 (m, br),
ꢀ
2924 (m), 2858 (m), 1638 (s) 1598 (vs), 1573 (m), 1524 (vs),
1465 (m), 1438 (m), 1380 (m), 1340 (s), 1304 (s), 1272 (m), 1240
(m), 1215 (s), 1173 (m), 1035 (s), 997 (vs, V@O), 908 (s), 870
(m), 817 (w), 761 (s), 670 (w), 640 (s), 476 (m). UV–Vis spectrum
All the three hydrazone ligands (H2L1–3) were synthesized by
the same general method. To a methanol solution (10 ml) of 3-hy-
droxy-2-naphthohydrazide (1.63 mmol), methanol (10 ml) solu-
tion of 2-hydroxybenzaldehyde (1.63 mmol) or its substituted
derivatives were drop-wise added and the mixture was refluxed
for 3 h. The solution was then evaporated on a steam bath to
5 cm3 and cooled to room temperature. Yellow crystals of H2L1–3
were separated and filtered off, washed with 5 ml of cooled meth-
anol and then dried in air.
in CH3OH [kmax, (e
, Mꢁ1 cmꢁ1)]: 203 (45 600), 230 (39 900), 268sh
(24 150), 318 nm (20 200). 1H NMR DMSO-d6 (ppm): 11.253 (1H,
s) (O–H), 9.092 (1H, s) (naphthohydrazide, 3-H), 8.468 (1H, s) (azo-
methine), 6.852-7.982 (8H, m) (aromatic), 3.782 (3H, s) (aryl-
OCH3), 3.148 (3H, s) (V–OCH3)
2.2.2. [Vvo(och3)(l2)] (2)
2.1.1. (E)-3-hydroxy-N0-(2-hydroxy-3-methoxybenzylidene)-2-
naphthohydrazide (H2L1)
Yield 0.41 g (86%). Anal. Calc. for C19H15N2O5V (MW = 402.27):
C, 56.73; H, 3.76; N, 6.96; V, 12.66. Found: C, 56.74; H, 3.77; N,
6.92; V, 12.70%. IR (KBr, cmꢁ1): 3421 (w,vb), 3011 (m, b), 2954
(m, b), 2908 (m, b), 2808 (m, b), 1636 (s) 1595 (vs), 1548 (m),
1514 (vs), 1462 (s, b), 1382 (m), 1335 (m), 1297 (s), 1217 (s),
1146 (m), 997 (vs, V@O), 987 (s), 898 (m), 865 (w), 836 (w), 800
Yield 0.54 g (98%). Mp (dp) 297 °C. Anal. Calc. for C19H16N2O4
(MW = 336.34): C, 67.85; H, 4.79; N, 8.33. Found: C, 67.80; H,
ꢀ
4.8; N, 8.43%. IR (KBr, cmꢁ1): 3462 (w, br) (
m
O–H) 3169 (s,vb)
ꢀ
ꢀ
m
ꢀ
(
m
N–H), 3085 (s, br), 2946 (m), 1654 (vs) (
C@O), 1615 (m) (
m
C@N),