Reaction of Silver(I) with Anthranilic Acid and Oxine

Article abstract of DOI:10.1023/A:1009501211223

It was found by elementary, crystal optics, X-ray diffraction analyses, and IR- and UV-spectroscopy methods that the reaction of Ag(I) with anthranilic acid (HAnt) and oxine (Ox) (at the 1 : 1 : 1 ratio of the components) yielded a mixed-ligand complex AgOxAnt · H₂O. It was shown that Ag(I) coordinated oxine in a neutral form and was bound with the nitrogen atom of Ox and with the oxygen atom of the deprotonated carboxylic group of Ant. An amino group of Ant^- was not coordinated by the silver atom. The complex isolated is highly soluble in 2N solutions of nitric acid and ammonia and in concentrated sulfuric acid.

Full text of DOI:10.1023/A:1009501211223

Russian Journal of Coordination Chemistry, Vol. 27, No. 1, 2001, pp. 70–72. Translated from Koordinatsionnaya Khimiya, Vol. 27, No. 1, 2001, pp. 77–79.
Original Russian Text Copyright © 2001 by Ivlieva, Gridasova, Zaitsev, Ezhov.
Reaction of Silver(I) with Anthranilic Acid and Oxine
V. I. Ivlieva, R. K. Gridasova, B. E. Zaitsev, and A. I. Ezhov
Peoples’Friendship University, Moscow, Russia
Received March 27, 2000
Abstract—It was found by elementary, crystal optics, X-ray diffraction analyses, and IR- and UV-spectroscopy
methods that the reaction of Ag(I) with anthranilic acid (HAnt) and oxine (Ox) (at the 1 : 1 : 1 ratio of the com-
ponents) yielded a mixed-ligand complex AgOxAnt · H2O. It was shown that Ag(I) coordinated oxine in a neu-
tral form and was bound with the nitrogen atom of Ox and with the oxygen atom of the deprotonated carboxylic
group of Ant. An amino group of Ant– was not coordinated by the silver atom. The complex isolated is highly
soluble in 2N solutions of nitric acid and ammonia and in concentrated sulfuric acid.
Study of the conditions for formation of mixed-
The compound isolated is insoluble in cold and hot
ligand complexes is of particular interest for the devel- water, n-heptane, diluted acetic acid and alkali, DMF,
opment of new sensitive and selective analytical tech- DMSO, amyl alcohol, toluene, acetone, carbon tetra-
niques. Mixed-ligand complexes play a key role in chloride, ether, and ethanol. It is readily soluble in
homogeneous catalytic reactions and biochemical pro- dilute (2N) sulfuric acid, concentrated hydrochloric
cesses [1, 2]. The selective binding of silver with nucle- acid, and dilute ammonia.
otide bases is well known. The study of silver and its
compounds as models is urgent for the investigation of
complicated biochemical processes.
Crystallooptical analysis showed that the compound
isolated contains only one phase and forms good
The silver complexes with anthranilic acid and
oxine were described in [3], but the interaction of silver
with anthranilic acid and oxine in combination has not
been studied. The present work is aimed at the investi-
gating the interaction, isolation, and characterization of
the compound formed.
Table 1. Interplanar distances and line intensity of diffrac-
tion patterns of binary compounds and mixed-ligand com-
plex [AgOxAnt] · H2O
[AgOxAnt] · H2O
AgAnt · H2O
Ag(Ox–H) · 2H2O
d, Å
I/I0, %
d, Å
I/I0, %
d, Å
I/I0, %
11.95
11.33
7.02
6.32
5.98
5.61
4.77
4.17
4.04
3.75
2.95
2.82
2.80
2.67
2.48
2.41
2.39
2.24
1.96
1.71
100
68
8
11.79
5.98
4.77
4.17
4.00
3.43
3.20
2.98
2.81
2.68
2.52
2.42
2.35
2.26
2.24
2.19
1.81
1.65
100
92
26
48
16
80
8
20
20
20
20
20
15
8
10.05
9.21
5.98
5.37
4.19
4.02
3.63
3.59
3.57
2.40
2.08
1.46
1.24
100
54
17
17
26
43
17
18
24
40
14
9
EXPERIMENTAL
The starting materials were silver nitrate and
reagent grade 8-oxyquinoline (oxine), and anthranilic
acid was recrystallized from an ethanol. The reaction
proceeds upon mixing of an aqueous solution of silver
nitrate, sodium anthranilate, and an alcoholic solution
of oxine (Ox) in a 1 : 1 : 1 ratio. Immediately after mix-
ing of the reagent solutions, a light grey precipitate
forms, the reaction mixture having a pH of 6. After one
day, the precipitate was filtered off, washed with dis-
tilled water to remove nitrate and silver ions, washed
with hot alcohol to remove excess oxine, and then dried
at an ambient temperature in a desiccator over KOH in
the absence of light.
15
20
30
30
48
43
30
14
9
8
11
4
8
8
9
The C,H,N elemental analysis was performed by the
Dumas microchemical method. The silver content was
determined by the gravimetric method using calcina-
tion at 800°ë.
20
28
8
For [AgOxAnt] · H2O
8
3
2
4
anal. calc (%): Ag, 26.60; C, 47.29; H, 3.97; N, 6.89.
Found (%): Ag, 25.57; C, 47.28; H, 6.11; N, 6.33.
1070-3284/01/2701-0070$25.00 © 2001 åÄIä “Nauka /Interperiodica”

REACTION OF SILVER(I) WITH ANTHRANILIC ACID
71
Table 2. Some vibrational frequencies (cm–1) in the IR-spectra of ligands, binary compounds, and [AgOxAnt] · H2O
Ox
Ag(Ox–H) · 2H2O
3430–3320
HAnt
AgAnt · H2O
[AgOxAnt] · H2O
Assignment
ν(OH)*
νas(NH2)
νs(NH2)
3100–3050, 2320
3310–3220
3465
3121
3425
3320
3150–3050
3420
3360
3320
1670
ν(C=O)
1530 s
1393 s
706 m
753 vs
800 m
867 m
1520 s
1370 s
750 vs
785 m
805 m
820 m
νas(COO–)
νs(COO–)
705 m
735 vs
775 m
810 m
700 m
730 m
775 vs
820 m
707 w
735 s
795 w
867 w
Out-of-plane deforma-
tion vibrations of the
CH bonds of the aro-
matic rings
* Stretching vibrations of the OH and COOH groups and H O molecule.
2
needle-shaped grey crystals, having a refraction index most intensive is the band at 753 cm–1; the bands close
slightly higher than 1.60. The phase is optically aniso- to 707, 795 and 867 cm–1 have one-fifth the intensity of
tropic with low intensity interference colors. Triclinic the band at 753 cm–1. In the spectrum of the mixed
syngony is probable for the compound. A comparison ligand compound Ag(Ox)Ant · H2O, a very intense
of the crystallooptic characteristics of silver anthra- band around 750 cm–1, which is characteristic for
nilate and oxinate and those of the mixed-ligand com- HAnt, and a narrow band at 775 cm–1, which is charac-
pound showed the uniqueness of the latter.
teristic for Ox, were observed. This is evidence of the
occurrence of both ligands Ant– and Ox in the compo-
sition of the mixed-ligand compound. The other out-of-
plane deformation vibration bands of the CH bonds of
Ant and Ox aromatic rings overlap in the spectrum of
Ag(Ox)Ant · H2O.
X-ray phase analysis was carried out on a DRON-2
diffractometer, and monochromated CuKα radiation
was used. The absence of the intense lines of the binary
compounds Ag(Ox–H) · 2H2O and AgAnt · H2O from
the diffraction pattern of the compound synthesized is
evidence of the uniqueness of the complex.
The bands of the stretching vibrations of the C=O
group from the IR spectra of AgAnt · H2O and
Ag(Ox)Ant · H2O are absent, and the corresponding
band in the spectrum of HAnt is found at approximately
1670 cm–1. The bands νas(COO–) and νs(COO–) of the
deprotonated carboxylic group are found at 1530, 1393
and 1520, 1370 cm–1 in the spectra of AgAnt · H2O and
Ag(Ox)Ant · H2O, respectively. These facts point to the
participation of the COO– group in the coordination.
The bands of the stretching vibrations of the Ant–
amino group are clearly seen in the spectra of HAnt at
3465, 3360 cm–1 and in that of Ag(Ox)Ant · H2O at
3420, 3320 cm–1. The frequency difference between
νas(NH2) and νs(NH2) for HAnt and the mixed ligand
complex is approximately 100 cm–1. This implies that
the amino group is not coordinated by the metal atom
Infrared spectra (400–4000 cm–1) were recorded
either in KBr pellets or Nujol mulls on a UR-20 spec-
trophotometer.
Electron absorption spectra were recorded on a
Specord UV–Vis spectrophotometer in the range of
200–400 nm.
RESULTS AND DISCUSSION
The anthranilic acid ligand can occupy three coordi-
nation sites: the metal atom can be bound with a nitro-
gen atom of the amino group and with two oxygen
atoms of the carboxylic group. The mode of coordina-
tion of the ligands in the compound synthesized was
determined on the basis of the IR spectra of the ligands.
The data for the binary compounds Ag(Ox–H) · 2H2O
and AgAnt · H2O and the complex Ag(Ox)Ant · H2O
(Table 2), along with the data from [4], were used.
In the spectra of oxine, anthranilic acid, Ag(Ox–H) ·
2H2O, AgAnt · H2O, and Ag(Ox)Ant · H2O, four bands
in the range of 700–867 cm–1 were assigned to the out-
of-plane deformation vibrations of the CH bonds of the
aromatic rings. In the spectrum of oxine, these bands
have practically equal intensity with a frequency differ-
in the complex, since the coordination M
NH2
decreases the frequency difference by 1.5–2 times. The
frequencies of the stretching vibrations of group NH2
decrease to approximately 40 cm–1 on passing from
HAnt to Ag(Ox)Ant · H2O. This decrease in νas(NH2)
and νs(NH2) can be associated with the participation of
the amino group in the formation of hydrogen bonds in
the complex.
The data of the electron absorption spectra of the
ence of approximately 30–40 cm–1. In the spectrum of ligands, the binary compounds, and the mixed ligand
Ag(Ox–H) · 2H2O, these bands essentially do not alter complex are listed in Table 3. The spectra of anthranilic
their position. In the spectrum of HAnt in this range, the acid and oxine differ significantly. In the spectrum of
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 27 No. 1 2001

72
IVLIEVA et al.
Table 3. Electronic absorption spectra of the ligands, binary
shifted to approximately 330 nm, suggests that the NH2
group does not participate in the coordination in both
AgAnt · H2O and Ag(Ox)Ant · H2O.
compounds, and [AgOxAnt] · H2O
Compound (medium)
HAnt (C2H5OH)
λmax, nm
It is known thatAg(I) have a coordination number of
2 [5]. Since oxine is coordinated in a neutral form and
Ant– is coordinated in the anionic form with the amino
group not coordinated, one can propose the following
structure for the mixed-ligand complex Ag(Ox)Ant ·
H2O.
218
240
308
HAnt (NaOH)
Ox (C2H5OH)
Ox (NaOH)
218 vb 240 sh
308 vb
308
205
205
240 sh
243 sh, 256 312 b
Ox (HCl)
205, 218 252 sh
215 254
324 vb
333 vb
. ···
O
H
H
.
.
AgAnt · H2O (C2H5OH)
···
Ag O
N
N
C
[Ag(Ox–H] · 2H2O (C2H5OH) 206
242, 263 sh 312 vb
H2O
[AgOxAnt] · H2O (C2H5OH) 205, 218 240, 252 sh 333 vb
OH
The water molecule is bound with the complex by
hydrogen bonds.
the ethanol solution of oxine, the bands with λmax 205
and 240 nm have the intensity ratio A240/A205 = 3,
whereas in the spectrum of HAnt, bands at 218 and
240 nm with A240/A218 = 0.5 are observed. Moreover, in
the spectrum of HAnt in ethanol, a medium intensity
band at 304 nm (ε ≈ 1000) is observed. This band is
REFERENCES
1. Inorganic Biochemistry, Eichhorn, G., Ed., Amsterdam:
Elsevier, 1975.
assigned to electron transfer nl
π*—the unshared
2. Umland, F., Janssen, A., Thierig, D., and Wönsch, G.,
Theorie und praktische Anwendung von Komplexbild-
nern (Theory andApplications of Complexes), Frankfurt
am Main: Akademische Verlagsgesselschaft, 1971.
3. Gridasova, R.K. and Ivlieva, V.I., Abstracts of Papers,
XXXI Nauchnaya konferentsiya fakul’teta fiziko-mate-
maticheskikh i estestvennykh nauk RUDN (XXXI Scien-
tific Conf. of the Department of Physics, Mathematics,
and Natural Sciences of the Peoples’ Friendship Univer-
sity), Moscow, 1995, part III, p. 7.
4. Zheligovskaya, N.N. and Chernyaev, I.N., Khimiya
kompleksnykh soedinenii (Chemistry of Complex Com-
pounds), Moscow: Vysshaya Shkola, 1996, p. 388.
5. Stepin, B.D. and Tsvetkov, A.A., Neorganicheskaya
khimiya (Inorganic Chemistry), Moscow: Vysshaya
Shkola, 1994, p. 393.
electron pair of the nitrogen atom of the amino group
also contributes significantly.
In the electronic absorption spectrum of the mixed
ligand complex Ag(Ox)Ant · H2O in ethanol, absorp-
tion bands characteristic of both ligands are found. The
intensive band at 240 nm is assigned to a quinoline
transfer of the ligand Ox. The band at 218 nm is
assigned to an aromatic transfer inAnt–. The latter band
overlaps the less intense band of oxine at 205 nm. The
absence of the intense band with λmax = 256 nm (char-
acteristic for the anion form of oxine observed in alka-
line solution) from the spectrum of [AgOxAnt] ·H2O
indicates that Ox is coordinated in a neutral form. The
retention of the band of nl
π* transfer, which is
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 27 No. 1
2001