Synthesis and Investigation of Complex Compounds Of 3d-Metals With 3-Amino-1,2,4-Triazole

American Journal of Applied Science and Technology

82

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VOLUME

Vol.05 Issue 05 2025

PAGE NO.

82-88

DOI

10.37547/ajast/Volume05Issue05-18

Synthesis and Investigation of Complex Compounds Of
3d-Metals With 3-Amino-1,2,4-Triazole

S.G. Usmonova

Teacher at Department of Medical and Biological Chemistry of Andijan Branch of Kokand University, Uzbekistan

Z.M. Chalaboyeva

Teacher at Department of Medical and Biological Chemistry of Andijan Branch of Kokand University, Uzbekistan

M.M. Mirzayeva

Teacher at Department of Medical and Biological Chemistry of Andijan Branch of Kokand University, Uzbekistan

Sh. A. Kadirova

Professor of the Faculty of Inorganic Chemistry at National University of Uzbekistan, Uzbekistan

Received:

24 March 2025;

Accepted:

20 April 2025;

Published:

22 May 2025

Abstract:

The currently available scientific, technical, and patent literature contains a sufficient amount of general

information on coordination compounds of biometals with various derivatives of triazole. However, this
information is fragmented, and the complexation reactions have not been systematically studied. The present work
is a scientific study focused on the systematic investigation of the structure and properties of previously unknown
coordination compounds of Ni(II), Cu(II), and Zn(II) chlorides with 3-amino-1,2,4-triazole.

Keywords:

Amitrole, IR spectroscopy, complex, solubility, ligand, quantum chemical calculation, geometry

optimization, thermal analysis, scanning electron microscopy.

Introduction:

Research Objective

: To develop a synthesis method

for new complex compounds of Ni(II), Cu(II), and Zn(II)
chlorides with 3-amino-1,2,4-triazole (L).

METHODOLOGY

Elemental analysis, SEM-EDTA, thermal analysis, IR
spectroscopy, quantum chemical calculations.

Scientific Novelty: For the first time, complex
compounds of some 3d-metals based on 3-amino-
1,2,4-triazole

have

been

synthesized.

The

composition and structure of the synthesized
compounds were studied using elemental analysis,
thermal analysis, and IR spectroscopy. Quantum
chemical calculations were performed using the
Biovia Accelrys Materials Studio software with the
PM-6 method to determine the

ligand’s electronic

structure, geometrical parameters, and energetic

characteristics. The most probable coordination
centers were identified based on charge distribution
analysis.

Introduction

: One of the rapidly developing areas of

organic chemistry is the chemistry of heterocyclic
compounds. Based on these, it is possible to
synthesize new, low-toxic, and environmentally safe
analogs of natural substances that can be used in
medicine, agriculture, chemical technology, and
analytical chemistry. The synthesis of new
coordination compounds of transition metals based
on heterocyclic compounds contributes to the
expansion of the range of biologically active
substances used as pharmaceuticals and chemical
agents for protection against diseases, pests, and
weeds, as well as plant growth regulators that are
safe for humans and the environment. The study of

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American Journal of Applied Science and Technology (ISSN: 2771-2745)

coordination compounds based on heterocyclic
structures is important not only for expanding their
practical application but also for addressing
fundamental issues in coordination chemistry, such
as the nature of chemical bonding, molecular
structure, and properties.

In coordination chemistry of transition metals,
nitrogen-containing heterocycles represent one of
the most important classes of ligands, among which
derivatives of 1,2,3-triazole, 3-amino-1,2,4-triazole,
and others are widely studied [1

–

3].

It has been established that coordination compounds
of 3-amino-1,2,4-triazole derivatives with metals also
exhibit biologically active properties. Complexes of
certain d-metals with aminotriazole derivatives have
been synthesized and are widely used in medicine
(e.g., antibacterial agents, cardiac stimulants) [4

–

5],

in the production of inhibitors [6

–

8], herbicides [9

–

10], catalysts [11], and fungicides [12

–

13]. The study

of the application areas of coordination compounds
of 3-amino-1,2,4-triazole derivatives in medicine,
agriculture, and industry holds great theoretical and
practical significance. The aim of this research is the
synthesis,

structural

investigation,

and

characterization of new complexes containing 3-
amino-1,2,4-triazole derivatives as ligands.

Materials and Methods: Chlorides of Ni(II), Cu(II), and

Zn(II) of analytical grade (“chemically pure”) were

used in the work. The organic reagents and solvents
used were purified and dried by standard methods
[14].

The synthesis of complexes of 3-amino-1,2,4-triazole
with chlorides of Cu(II), Zn(II), and Ni(II) was carried
out by dissolving amitrole in 0.042 g of ethanol and
stirring it on a magnetic stirrer. An aqueous (hot)
solution of 0.034 g of copper(II) chloride, 0.035 g of
zinc chloride, or 0.065 g of nickel(II) chloride was
added dropwise while stirring. The mixture was
stirred for 3 hours at room temperature using a
magnetic stirrer. The solution was cooled to room
temperature and filtered again (until a clear solution
was obtained), then evaporated at room temperature
under reduced pressure.

As a result of slow solvent evaporation over several

days, green crystals with CuCl₂ and violet crystals with
NiCl₂ w

ere formed. The resulting crystals are stable in

air, non-hygroscopic, and well soluble in organic

solvents. The melting points are: NiCl₂ –

297°C, CuCl₂

–

295°C, and ZnCl₂ –

298°C.

The results of the synthesized compounds, their
melting points, and elemental analysis data are
presented in Table 1.

Table 1. Results of elemental analysis and selected properties of transition

metal complexes with ligand L

№

Compound

Color

%

Т

пл,

0

С

Found (%)

Calculated (%)

C

H

N

M

Formula Brutto

C

H

N

M

1

L

White

157-

159

28,6

4,76

33,3

C

2

N

4

H

4

29,1

4,26

32,9

2

Cu(C

2

N

4

H

4

)

5

Cl

2

Green

294-

295

21,6

3,60

50,5

11,5

C

10

N

20

H

20

Cl

2

Cu

20,9

3,45

49,8

10,9

3

Ni(C

2

N

4

H

4

)

5

Cl

2

(H

2

O)

2

Violet

296-

297

20,5

4,09

47,8

10,1

C

10

N

20

H

24

Cl

2

O

2

Ni

21,3

4,01

48,2

11,2

4

Zn(C

2

N

4

H

4

)

4

Cl

2

(H

2

O)

4

White

297-

298

17,6

4,41

41,2

11,9

C

8

N

16

H

24

Cl

2

O

4

Zn

18,6

4,49

41,9

11,1

The content of nitrogen, sulfur, and metal in the
obtained metal complex compounds was determined
using the SEM-EDTA method, on the basis of which,
along with energy-dispersive analysis, it can be
concluded that the complexation of metal ions with

the organic ligand leads to changes in the
microstructure of the latter. In particular, numerous
metal peaks were recorded, which is confirmed in
Table 2.

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American Journal of Applied Science and Technology (ISSN: 2771-2745)

Element

Mass %

Atom %

C

18.87

0.01

N

61.11

0.04

O

1.35

0.01

Cl

7.03

0.01

Cu

11.41

0.02

Table 2. Microstructure of the metal complex compound Cu(C

₂

N

₄

H

₄

)

₅

Cl

₂

As a result of studying the solubility of the metal
complex compounds in various solvents, it was

concluded that they are poorly or practically insoluble
in benzene and DMF, but dissolve well in water,
ethanol, and acetonitrile (Table 3).

Table 3. Solubility of the synthesized metal complex compounds based on

ligand L

№

Compound

Water

Ethanol

Benzene

DMF

Acetonitrile

1

L

Р.S.

S

I.S.

Р.S.

S

2

Cu(C

2

N

4

H

4

)

5

Cl

2

S

S

Р.S.

Р.S.

S

3

Ni(C

2

N

4

H

4

)

5

Cl

2

(

H

2

O)

2

S

S

Р.S.

Р.S.

S

4

Zn(C

2

N

4

H

4

)

4

Cl

2

(H

2

O)

4

S

S

Р.S.

Р.S.

S

Note: S – soluble, P.S. – poorly soluble, I.S. – insoluble

RESULTS AND DISCUSSION

The synthesized ligand is characterized by the
presence of various functional groups containing
multiple donor atoms. To enable the targeted
synthesis of metal complexes, a quantum chemical
calculation of the reactivity of the synthesized ligand
was performed using the PM3 and MNDO quantum

chemical methods in ChemOffice Ultra [15]. The
nitrogen atoms in the amino group possess a higher
negative effective charge compared to the nitrogen
atoms located in the ring. Despite their significant
negative effective charge, these donor atoms do not
participate in the formation of coordination
complexes.

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Figure 1 a Figure 1 b

Figure 1 (a, b) – Diagram of electron density distribution of the 3-amino-1,2,4-

triazole ligand calculated by the MNDO method

To determine the coordination center, IR spectra of
the ligand and its corresponding complex were
recorded (Fig. 2). An attempt was made to evaluate
the electron

–

conformational changes upon complex

formation using IR spectroscopy.

The ligand, amitrole, contains several functional
groups. Intense asymmetric stretching vibrations of
the C=N group are observed in the region of 1537

–

1560 cm⁻¹, while

symmetric vibrations are found in

the region of 729

–828 cm⁻¹. Symmetric and

asymmetric stretching and bending vibrations of the
amino group are observed at 3331, 3414, 1271, 1373,

and 1593 cm⁻¹, respectively. The stretching vibration

of the C

–

N bond appear

s around 968 and 1425 cm⁻¹.

It is evident that in the IR spectra of the complexes of
amitrole with zinc and copper chlorides, a shift in the

frequencies of the asymmetric and symmetric
stretching vibrations of the C=N group is observed by
6

–

11 and 26

–

32 cm

⁻¹, respectively, compared to the

ligand spectrum (Table 4).

This indicates that the complexes are formed through
the lone electron pairs of nitrogen in the heterocycle.
Symmetric and asymmetric stretching vibrations of
the amino group may also change, presumably due to
electron redistribution during the formation of
coordination compounds.

The absence of absorption line broadening in the
3000

–3400 cm⁻¹ region confirms the absence of

moisture in the complexes. The appearance of new
vibrational frequencies corresponding to M

–

N

stretching vibrations in the region of 473

–642 cm⁻¹

provides evidence of complex formation [16].

Table 4. IR spectroscopic analysis of the complexes

Type of

vibration

.

ν

a

C=



as

C=N

N



s

NH

2



NH

2



C-N



s

C=N



as

NH

2



M→N

L

1537,1560

1271,1373

1593

968,1425

729,878

3331,3414

-

CuL

1508

1261,1288

1632

1063,1477

725,870

3298

473

NiL

1508

1248

1629,1641

1058

988

2776,3630

642

ZnL

1527,1566

1307

1610,1639

1020,1425

743,881

3385

486

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American Journal of Applied Science and Technology (ISSN: 2771-2745)

А

B

Figure 2: (A, B) IR spectra of the ligand (A) and its complexes (B)

Thermogravimetric analysis of the complexes was
carried out in the temperature range of 20

–

1000°C.

On the TG curve of the complex compound

[Cu(L)₅]Cl₂, an exothermic effect is observed in the

region of 250

–

335°C, accompanied by a mass loss of

75.9% of the total weight. Based on this, it can be
assumed that the remaining mass corresponds to the

composition C₁₀N₂₀H₂₀Cl₂Cu, i.e., it matches the

formula Cu(C₂N₄H₄)₅Cl₂ (Figure 3).

On the TG curve of the complex compound

[Ni(L)₄]Cl₂(H₂O)₂, an exothermic effect is

observed in

the region of 420

–

780°C, along with a mass loss of

74.9% of the total weight. Based on this, it can be
assumed that the remaining mass corresponds to the

composition C₁₀N₂₀H₂₄Cl₂O₂Ni, which corresponds to
the formula Ni(C₂N₄H₄)₅Cl₂(H₂O)₂ [17,1

8].

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Figure 3. Thermogram of the complex compound [CuL

₅

]Cl

₂

CONCLUSION

A method for the synthesis of complexes of 3-amino-
1,2,4-triazole with copper(II) and nickel(II) chlorides
has been developed, and the corresponding complex
compounds have been synthesized. These complexes
are well soluble in fresh water. The composition and
structure of the synthesized complexes were studied
using physicochemical methods. It was established
that the metal complexes of 3-amino-1,2,4-triazole
with copper(II) and nickel(II) chlorides in a metal-to-
ligand ratio of 1:5 are thermally more stable than the
ligand itself and possess a unique crystal lattice.
Based on IR spectroscopic analysis, the geometry of
the synthesized complexes depends on the nature of
the metal and corresponds to monodentate
coordination.

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