[3.1] instruments and experimental …shodhganga.inflibnet.ac.in/bitstream/10603/37759/8/08...acetic...
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61
[3.1] INSTRUMENTS AND EXPERIMENTAL PARAMETERS:
INSTRUMENTS:
SPECTROPHOTOMETER:
The absorbance measurements were done on a "Milton Roy"
(Spectronic-20D+) Spectrophotometer and "Abotta make UV-1100, UV-Visible
Spectrophotometer". The IR spectra were recorded on "Perkin-Elmer" FTIR
Spectrophotometer (RX-1) in KBr pallet. The NMR spectra were recorded on
"Bruker Avance II 400 NMR Spectrometer.
pH METER:
The pH of the solutions were measured on Equip-Tronic pH meter (Model
No. EQ 614) and solutions of required pH were obtained using sodium acetate-
acetic acid, sodium acetate-HCl, NH3-NH4Cl or Borax-HCl buffer of suitable
concentrations.
TEMPERATURE:
All the experiments, including the preparation of the solutions, extraction of
the complex, recording the observation etc. were carried out at room
temperature.
MATERIALS:
All chemicals used throughout this work were of analytical grade.
EFFECT OF TIME ON THE ABSORBANCE OF THE CHELATE:
The colour development due to the formation of metal chelates was found
to attain constancy in absorbance values within five minutes and were found to
be constant for sufficient long period. Details for each chelate is given with the
study of respective chelate.
62
EFFECT OF ORDER OF ADDITION OF THE REAGENT:
The effect of order of addition of the reagent was observed in all
experiments. It is found that the order of addition of the reagent had no effect.
However in alkaline conditions, it was necessary to add reagent first and buffer
afterwards, to prevent precipitation of metal hydroxides.
NUMBER OF COMPLEX SPECIES FORMED:
In order to ascertain the number of complexes formed in each case, under
the experimental conditions, the method of W.C. Vosburgh and G.R. Cooper
[208] was employed. Several mixtures containing metal ion and the ligand in the
ratio 1:1, 1:2, 1:3 and 1:4 were prepared at selected pH. The absorbances of the
solutions were measured between a selected range of wavelength. In second
experiment, several mixtures containing stoichiometry amount of metal ion and
ligand were prepared at different pH values and the absorbance of the complexes
were measured. By the number of shifts in the region of maximum absorbance of
the mixtures from the max of the reagent itself, the number of complexes formed
was ascertained. During the studies, it was found that only one complex was
formed in all cases under the experimental conditions.
DETERMINATION OF CONDITIONAL STABILITY CONSTANT:
The conditional stability constant for the complexes were determined from
Yoe and Jone's mole ratio method and Job's method of continuous variation. The
Gibb's free energy change Go for the complex formation reactions were also
calculated.
ANALYTICAL APPLICATIONS OF THE METAL CHELATES:
BEER'S LAW:
The obeyance of the Beer law was studied for the metal chelates under
investigation by varying metal ion concentrations and adding the excess reagent
in constant amount and measuring the absorbance at wavelength of maximum
absorbance and at pH where maximum complex formation occurs. The range of
63
concentration for obeyance to the Beer law expressed in ppm for each system
has been determined from the graph.
MOLAR ABSORPTIVITY:
The values of molar absorptivities were calculated for all complexes. The
values of molar absorptivities are expressed in lit.mole-1.cm-1.
[3.2] PREPARATION OF SOLUTIONS AND SYNTHESIS OF
REAGENT:
Preparation of Metal Ion Solutions:
Four metal salts,
(i) FeCl3 (Anhydrous) : (M.Wt. = 162.21)
(ii) PdCl2 : (M.Wt. = 177.21)
(v) CuSO4.5H2O : (M.Wt. = 249.68)
(vi) NiSO4.6H2O : (M.Wt. = 262.71)
were used for the present work.
All the metal salts except PdCl2 are soluble in water. Stock solutions of all
the salts were prepared by dissolving the requisite amount of salts in doubly
distilled water. A little free acid was added to prevent hydrolysis. Solutions of
desired concentrations were obtained by suitable dilution of stock solutions. In
case of PdCl2, requisite quantity was first dissolved in few mL concentrated HCl
and then diluted with water.
* SYNTHESIS OF REAGENTS:
The detailed experimental procedure for the synthesis of the reagents are
given below:
[A] 2'-HYDROXY-4'-BUTOXYCHALCONE OXIME :
(i) RESACETOPHENONE FROM RESORCINOL:
It was prepared from resorcinol, glacial acetic acid and anhydrous zinc
chloride according to the method of R. Robinson and R.C. Shah [165].
Resorcinol Acetic acid Resacetophenone
HO OH OHHO
C=O
CH3
+ CH3COOHAnhy.
ZnCl2
64
(ii) 2-HYDROXY-4-BUTOXYACETOPHENONE:
Resacetophenone (15.2 g, 0.1 mole), n-butyl bromide (13.7 g, 0.1 mole),
and anhydrous potassium carbonate (13.81 g, 0.1 mole) in acetone was refluxed
on a water bath at 65-700C for six hours. The mixture was then poured over
crushed ice and acidified with diluted HCl. The solid separated was filtered out,
washed with water, dried and crystallized from ethanol. Light yellow crystals
obtained, m.p. 65oC.
OHOH
C = O
CH3
OHC4H
9O
C = O
CH3
n-butyl bromide
Resacetophenone 2-Hydroxy-4-butoxy-
acetophenone
(iii) 2'-HYDROXY-4'-BUTOXYCHALCONE:
To a solution of 2-hydroxy-4-butoxyacetophenone (10.4 g, 0.05 mole) and
benzaldehyde (5.3 g, 0.05 mole) in ethanol (20 ml), aqueous solution of KOH (20
ml, 40%) was added dropwise with vigorous stirring and the flask was cooled
under the cold water tap so as to keep the reaction temperature 20-25oC. The
colour of the reaction mixture changed. The flask was tightly corked and was kept
at room temperature for 18 hours. The content was then poured over crushed ice
and acidified with dilute HCl. The solid separated was filtered out, washed with
water, dried and crystallised from benzene. Light orange crystals obtained,
m.p.135oC. Yield is 70 %.
OH
C = O
C4H
9O OH
C = O
C4H
9O
CHO
CH3
CH = CH
+Alcoholic
KOH
2-Hydroxy-4- Benzaldehyde 2'-Hydroxy-4'-butoxy
butoxyacetophenone chalcone
65
(iv) 2'-HYDROXY-4'-BUTOXYCHALCONE OXIME (HBCO):
The oxime was prepared by sodium acetate method. 2'-Hydroxy-4'-
butoxychalcone (2.0 gm) was dissolved in minimum quantity of ethanol. Aqueous
solutions of hydroxylamine hydrochloride (4.0 gm) and sodium acetate (6.0 gm)
were added to it. A little more alcohol was added to get clear solution. The
solution was refluxed on a water-bath at 75-80oC for four hours. The mixture was
poured on crushed ice with stirring, when light yellow oxime separated. It was
crystallised from ethanol (yield 1.5 gm), light yellow coloured crystals were
obtained, m.p. 178oC.
OH
C = O
C4H
9O
CH = CH
OH
C - CH = CH
C4H
9O
NH2OH.HCl
[CH3COONa]
N - OH
2'-Hydroxy-4'-butoxychalcone 2'-Hydroxy-4'-butoxychalcone
oxime (HBCO)
[B] 2'-HYDROXY-4'-METHOXYCHALCONE OXIME:
(i) RESACETOPHENONE FROM RESORCINOL :
It was prepared as described earlier.
(ii) 2-HYDROXY-4-METHOXYACETOPHENONE:
Resacetophenone (15.2 g, 0.1 mole), methyl iodide (14.19 g, 0.1 mole),
and anhydrous potassium carbonate (13.81 g, 0.1 mole) in acetone was refluxed
on a water bath at 65-700C for six hours. The mixture was then poured over
crushed ice and acidified with diluted HCl. The solid separated was filtered out,
washed with water, dried and crystallized from ethanol. Light yellow crystals
obtained, m.p. 45oC.
OHOH
C = O
CH3
OHCH3O
C = O
CH3
methyl iodide
Resacetophenone 2-Hydroxy-4-methoxy acetophenone
66
(iii) 2'-HYDROXY-4'-METHOXYCHALCONE:
To a solution of 2-hydroxy-4-methoxyacetophenone (8.3 g, 0.05 mole) and
benzaldehyde (5.3 g, 0.05 mole) in ethanol (20 ml), aqueous solution of KOH (20
ml, 40%) was added dropwise with vigorous stirring and the flask was cooled
under the cold water tap so as to keep the reaction temperature 20-25oC. The
colour of the reaction mixture changed. The flask was tightly corked and was kept
at room temperature for 18 hours. The content was then poured over crushed ice
and acidified with dilute HCl. The solid separated was filtered out, washed with
water, dried and crystallised from benzene. Light orange crystals obtained,
m.p.85oC. Yield is 70 %.
OH
C = O
CH3O OH
C = O
CH3O
CHO
CH3
CH = CH
+Alcoholic
KOH
2-Hydroxy-4- Benzaldehyde 2'-Hydroxy-4'-methoxy methoxyacetophenone chalcone (iv) 2'-HYDROXY-4'-METHOXYCHALCONE OXIME (HMCO):
The oxime was prepared by sodium acetate method. 2'-Hydroxy-4'-
methoxychalcone (2.0 gm) was dissolved in minimum quantity of ethanol.
Aqueous solutions of hydroxylamine hydrochloride (4.0 gm) and sodium acetate
(6.0 gm) were added to it. A little more alcohol was added to get clear solution.
The solution was refluxed on a water-bath at 75-80oC for four hours. The mixture
was poured on crushed ice with stirring, when light yellow oxime separated. It
was crystallised from ethanol (yield 1.5 gm), light yellow coloured crystals were
obtained, m.p. 142oC.
OH
C = O
CH3O
CH = CH
OH
C - CH = CH
CH3O
NH2OH.HCl
[CH3COONa]
N - OH
2'-Hydroxy-4'-methoxychalcone 2'-Hydroxy-4'-methoxychalcone
oxime (HMCO)
67
[C] 2-HYDROXY-4-METHOXYACETOPHENONE THIOSEMICARBAZONE:
(i) RESACETOPHENONE FROM RESORCINOL :
It was prepared as described earlier.
(ii) 2-HYDROXY-4-METHOXYACETOPHENONE:
It was prepared as described earlier.
(iii) 2-HYDROXY-4-METHOXYACETOPHENONE THIOSEMICARBAZONE:
A mixture of 2-hydroxy-4-methoxyacetophenone (2.0g), thiosemicarbazide
(2.0 g) in ethanol (30.0 ml) and glacial acetic acid (6.0ml) was refluxed on a
waterbath for four hours. The mixture was then poured in ice-cold water when
pale yellow coloured 2-hydroxy-4-methoxyacetophenone thiosemicarbazone was
separated. It was filtered, washed and crystallized from alcohol,pale yellow
crystals, insoluble in water, soluble in ethanol, m.p. 1660C.
OHCH3O
C = O
CH3
OHCH3O
C = N - N - C - NH2
CH3
H SS
NH2NH-C-NH
2
CH3COOH
2-Hydroxy-4-methoxy 2-Hydroxy-4-methoxyacetophenone thio-
acetophenone semicarbazone (HMAT)
PREPARATION OF REAGENT SOLUTION:
The reagents HBCO, HMCO & HMAT are soluble in 70% aqueous ethanol.
Reagent solutions were prepared by dissolving requisite amount in ethanol and
diluted to final volume so as to keep final concentration of ethanol 70%. The
reagent solutions were found to be stable for long time and could be kept for
months after preparation.
REACTIVITY OF LIGAND:
A 0.02 M solution of reagents were employed for checking its reactivity with
aqueous solution of metal ions at different pH values.
68
ANALYSIS OF REAGENT:
These reagents were analysed for its carbon, hydrogen and nitrogen
content. The percentage of these elements found are in agreement with their
molecular formula. The results are given in the following table:
Reagent Molecular formula
% Found (Calculated)
Carbon Hydrogen Nitrogen Sulphur
2'-Hydroxy-4'-butoxychalcone oxime (HBCO)
C19H21O3N 73.51 (73.31)
6.63 (6.75)
4.68 (4.50)
-
2'-Hydroxy-4'-methoxychalcone oxime (HMCO)
C16H16O3N 69.35 (71.11)
5.44 (5.92)
5.17 (5.19)
-
2-Hydroxy-4-methoxyacetophenone thio-
semicarbazone (HMAT)
C10H13O2N3S 44.86 (50.20)
4.83 (5.43)
14.35 (17.57)
23.40 (13.38)
UV-VISIBLE SPECTRA OF REAGENTS:
The UV-Visible spectra of reagents HBCO, HMCO and HMAT in ethanol
were recorded on "Systronics make, UV-Visible Spectrophotometer". The graph
is shown in figure-3.1(I), 3.1(II) and 3.1(III) respectively.
Reagent Molecular formula
max
2'-Hydroxy-4'-butoxychalcone oxime (HBCO)
C19H21O3N 250 nm
2'-Hydroxy-4'-methoxychalcone oxime (HMCO)
C16H15O3N 330 nm
2-Hydroxy-4-methoxyacetophenone thio semicarbazone (HMAT)
C10H13O2N3S 350 nm
69
ABSORPTION SPECTRA OF LIGAND HBCO
Fig. 3.1 (I)
ABSORPTION SPECTRA OF LIGAND HMCO
Fig. 3.1 (II)
70
ABSORPTION SPECTRA OF LIGAND HMAT
Fig. 3.1 (III)
71
IR SPECTRA OF LIGAND HBCO :
The important absorption bands are assigned. The spectra are given along
with the IR spectra of complexes.
Band Assignment
3200 to 3700 with peak
at 3400 cm-1
phenolic -OH
oximino -OH obscured by phenolic -OH
3000 cm-1 aromatic C-H stretching
2925 cm-1 aliphatic C-H stretching
1596 cm-1 C=N stretching
1525 cm-1 CH=CH stretching
NMR SPECTRA OF LIGAND HBCO :
It was taken on "BRUKER" NMR Spectrometer. Different signals are
assigned as follows.
OH
C - CH = CH
C4H
9O
N - OH
2'-Hydroxy-4'-butoxychalcone oxime (HBCO)
Chemical shift Assignment
1.004
1.284
1.520
1.779
protons of n-butoxy group
4.00 proton of oximino -OH
6.56 & 6.61 -CH=CH- protons
6.84 to 7.66 aromatic protons
7.87 phenolic -OH proton
72
IR SPECTRA OF LIGAND HBCO
Fig. 3.1 (IV)
NMR SPECTRA OF LIGAND HBCO
Fig. 3.1 (V)
73
IR SPECTRA OF LIGAND HMCO :
The important absorption bands are assigned. The spectra are given along
with the IR spectra of complexes.
Band Assignment
3429 cm-1
3200 cm-1
oximino -OH obscured by phenolic -OH
phenolic -OH broad band
3066 cm-1 aromatic C-H stretching
2924 cm-1 aliphatic C-H stretching
1510 cm-1 C=N stretching
1621 cm-1
1282 cm-1
CH=CH stretching
C=O stretching in phenol
961 cm-1 N-OH stretching
1165 cm-1 C-O stretching in ether
1521 cm-1 C=C stretching
NMR SPECTRA OF LIGAND HMCO :
It was taken on "BRUKER" NMR Spectrometer. Different signals are
assigned as follows.
OH
C - CH = CH
CH3O
N - OH
2'-Hydroxy-4'-methoxychalcone oxime (HMCO)
Chemical shift Assignment
3.769
3.794
3.802
protons of n-methoxy group
10.88 proton of oximino -OH
7.7 & 7.9 -CH=CH- protons
6.00 to 7.5 aromatic protons
10.44 proton of phenolic -OH
74
IR SPECTRA OF LIGAND HMCO
Fig. 3.1 (VI)
12 11 10 9 8 7 6 5 4 3 2 1 0 ppm
0.0000
1.2460
2.1182
2.2428
2.5441
2.5482
2.5519
2.6032
2.6330
2.6459
2.6755
3.3549
3.3766
3.3849
3.4197
3.4276
3.7177
3.7349
3.7375
3.7606
3.7694
3.7811
3.7940
3.8029
5.1039
6.3574
6.3637
6.4822
6.4881
6.5154
6.5226
6.5283
6.5446
6.5501
6.6087
6.6146
7.1073
7.1995
7.2462
7.2646
7.2849
7.3184
7.3322
7.3429
7.3627
7.3836
7.3974
7.4029
7.4204
7.4618
7.4763
7.4949
7.5093
7.5166
7.7257
7.7345
7.7477
7.7563
7.8590
7.8621
7.8775
7.8817
8.0818
9.8900
10.4482
10.8848
0.25
1.61
2.00
0.48
1.22
0.60
1.00
2.68
2.36
0.85
1.18
0.55
0.25
Current Data Parameters
NAME May03-2013
EXPNO 530
PROCNO 1
F2 - Acquisition Parameters
Date_ 20130504
Time 10.57
INSTRUM spect
PROBHD 5 mm PABBO BB-
PULPROG zg30
TD 65536
SOLVENT DMSO
NS 8
DS 2
SWH 12019.230 Hz
FIDRES 0.183399 Hz
AQ 2.7263477 sec
RG 362
DW 41.600 usec
DE 6.00 usec
TE 292.8 K
D1 1.00000000 sec
TD0 1
======== CHANNEL f1 ========
NUC1 1H
P1 10.90 usec
PL1 -3.00 dB
SFO1 400.1324710 MHz
F2 - Processing parameters
SI 32768
SF 400.1299845 MHz
WDW EM
SSB 0
LB 0.30 Hz
GB 0
PC 1.00
ABRUKER
AVANCE II 400 NMR
Spectrometer
SAIFPanjab University
Chandigarh
avtar_saifpu@yahoo.co.in
NMR SPECTRA OF LIGAND HMCO
Fig. 3.1 (VII)
RC SAIF PU, Chandigarh
Spectrum Name: Limbachiya-1.sp Description: A
Date Created: thu may 16 13:03:15 2013 India Standard Time (GMT+5:30)
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 450.0
33.0
34
36
38
40
42
44
46
48
50
52
54
56
58
60
62.4
cm-1
%T
3429
3066
2964
2924
2841
1881
1621
1574
1521
1510
1470
1448
1422
1405
1333
1282
1260
1246
1209
1165
1124
1059
1045
1030
1003
961
918
863
844
830
796
765
736
698
684
631
576
536
459
75
IR SPECTRA OF LIGAND HMAT :
The important absorption bands are assigned. The spectra are given along
with the IR spectra of complexes.
Band Assignment
3380 cm-1 phenolic -OH
1593 cm-1, 1621 cm-1 aromatic ring skeleton
2841 cm-1 aliphatic C-H stretching
1509 cm-1 C=N stretching
1484 cm-1 C=S stretching
3148 - 3265 cm-1 Symm. and asymm. stretching of -NH2 & N-H
str. (doublet)
1252 cm-1 C-O stretching of phenol
1000 - 1100 cm-1 C-O-C stretching of ether
2998 cm-1 aromatic C-H str.
NMR SPECTRA OF LIGAND HMAT :
It was taken on "BRUKER" NMR Spectrometer. Different signals are
assigned as follows.
OHCH3O
C = N - N - C - NH2
CH3
H S
2-Hydroxy-4-methoxyacetophenone thiosemicarbazone (HMAT)
Chemical shift Assignment
3.779 protons of n-methoxy group
12.60 proton of phenolic -OH
3.4065 protons of NH2 & NH
6.5 to 8.00 aromatic protons
9.720 proton of phenolic -OH
11.5676 -NH group
1.96 - 2.55 protons of -CH3 group
76
IR SPECTRA OF LIGAND HMAT
Fig. 3.1 (VIII)
14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ppm
0.0000
1.2471
1.8924
1.9433
1.9632
2.1208
2.2213
2.3155
2.5149
2.5578
3.4065
3.7793
3.8279
3.8331
6.3995
6.4049
6.4158
6.4214
6.4377
6.4435
6.4592
6.4654
6.4821
6.4878
6.5475
6.5527
6.9970
7.0161
7.0373
7.1250
7.2537
7.3506
7.3977
7.4193
7.5203
7.7295
7.7516
7.9331
8.0291
8.0634
9.7201
9.7846
10.6347
11.5676
12.6709
12.9855
0.61
2.55
0.20
0.21
2.84
3.00
2.07
0.12
0.15
0.20
0.68
1.43
0.58
0.68
0.38
0.19
0.08
0.75
0.49
0.28
0.65
Current Data Parameters
NAME May03-2013
EXPNO 540
PROCNO 1
F2 - Acquisition Parameters
Date_ 20130504
Time 11.03
INSTRUM spect
PROBHD 5 mm PABBO BB-
PULPROG zg30
TD 65536
SOLVENT DMSO
NS 8
DS 2
SWH 12019.230 Hz
FIDRES 0.183399 Hz
AQ 2.7263477 sec
RG 512
DW 41.600 usec
DE 6.00 usec
TE 292.9 K
D1 1.00000000 sec
TD0 1
======== CHANNEL f1 ========
NUC1 1H
P1 10.90 usec
PL1 -3.00 dB
SFO1 400.1324710 MHz
F2 - Processing parameters
SI 32768
SF 400.1299796 MHz
WDW EM
SSB 0
LB 0.30 Hz
GB 0
PC 1.00
BBRUKER
AVANCE II 400 NMR
Spectrometer
SAIFPanjab University
Chandigarh
avtar_saifpu@yahoo.co.in
NMR SPECTRA OF LIGAND HMAT
Fig. 3.1 (IX)
RC SAIF PU, Chandigarh
Spectrum Name: Limbachiya-2.sp Description: B
Date Created: thu may 16 13:04:29 2013 India Standard Time (GMT+5:30)
4000.0 3600 3200 2800 2400 2000 1800 1600 1400 1200 1000 800 600 450.0
12.0
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48.5
cm-1
%T
3380
3265
3148
2998
2960
2841
2061
1874
1621
1593 1509
1484
1469
1440
1374
1342
1252
1234
1200
1170
1152
1135
1088
1043
1022
973
947
866
839
792
753
721
593
528
494
470
457
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