COMPLEX COMPOUND OF ZINC NITRATE BASED ON FORMAMIDE AND NICOTINIC ACID

ABSTRACT

A complex compound of zinc nitrate with formamide and nicotinic acid is synthesized. The advantages of the mechanochemical method, optimal synthesis conditions are presented. In the IR-spectroscopy method, the bond nature ligands and the complex compound formed on their basis, in the central atomic ring, polyedre, shifts the valence and deformation oscillations, mass spectrometric data, fragmentation of ions and their scheme and the masses of the formed ions are expressed.

АННОТАЦИЯ

Синтезированo комплексное соединение нитрата цинка с формамидом и никотиновой кислотой. Представлены преимущества механохимического метода, оптимальные условия синтеза. В методе ИК-спектроскопии лиганды и природа связей образовавшего на их основе комплексного соединения, в центральном атомном кольце полиэдра, сдвиги валентных и деформационных колебаний, масс-спектрометрические данные, фрагментация ионов и их схема, массы образующихся ионов выражены.

Keywords: synthesis, ligand, complex compound, IR spectrum, bond nature, polyhedron, mass spectrometry, fragmentation of ions.

Ключевые слова: синтез, лиганд, комплексное соединение, ИК-спектр, природа связи, полиэдр, масс-спектрометрия, фрагментация ионов.

Introduction

In the world, research is underway to carry out the synthesis of coordination compounds of metal salts with amides and develop optimal methods for the synthesis of biologically active substances and stimulants with a highly effective complex effect. In this regard, special attention is paid to reducing the vegetative period of plants, substantiating scientific solutions for creating stimulants that increase their yield, including the development of favorable conditions for the synthesis of a complex combination of zinc ion with formamide and nicotinic acid, determining their composition, structure and physico-chemical and biological properties [1].

Research methodology

The synthesis of coordination compounds of zinc nitrate with organic ligands was carried out by the mechanochemical method (solid phase) [2]. To determine the optimal conditions for conducting a reaction, we used the mechanochemical reaction in a ball mill 0.5; for 0.75 hours, the 1^st and 2^nd working part (a sphere with a diameter of 20 mm) was used. The mass of the working part is 67 grams. The number of revolutions per minute is 150 rev/min the duration of mixing once is 30 seconds. Three such mixing is one cycle, the time between cycles is 2-3 seconds. In the synthesis of a mixed ligand complex compound of zinc nitrate with ligands, zinc nitrate and ligands were mixed in equimolar proportions 1:1:1 (Zn(NO₃)₂∙6H₂O:HCONH₂:NC₅H₄COOH). For the synthesis of containing compounds [ZnHCONH₂∙NC₅H₄COOH∙(NO₃)₂]∙3H₂O were carried 0.001 moles of zinc nitrate, 0.001 moles of HCONH₂, 0.001 moles of NC₅H₄COOH out by intensive mixing in a ball mill for 30 minutes [3]. In the synthesis of a mixed ligand complex compound of zinc nitrate, initially with the onset of mixing, substances come to the same homogenous state (i.e. to a liquid state), that is, the crystallization water molecules are separated and instead of ligand molecules are coordinated. During mixing, it turns into an adhesive state by 7-9 cycles. When the mixing continued - it became dry powder in cycles 15-17 [4].

Zn(NO₃)₂∙6H₂O + HCONH₂ + NC₅H₄COOH → [ZnHCONH₂∙NC₅H₄COOH ∙(NO₃)₂]∙3H₂O + 3H₂O

The quantitative content of the metal in the synthesized complex compound was determined by atomic absorption spectrometry on the novAA 300 instrument from Analytic Jena AG (Germany) [5], and the amount of elements was determined on the EuroEA3000 CHNS-O Analyzer (Eurovector S.p.A., Milan, Italy) [6].

Analysis and results

An element analysis of the synthesized new complex compound was carried out (Table 1).  

Table 1.

Result the method element analysis of the complex compound [ZnHCONH₂∙NC₅H₄COOH∙(NO₃)₂]∙3H₂O

Based on the differences in the spectrum of the complex with the initial components, the data of the IR-spectroscopy method are used in the analysis of the structure of the obtained complexes due to the possibility of new interaction and conclusion about new bonds. IR spectra absorption areas were recorded on the IR Tracer–100 (500-4000 cm^-1) spectrometer from SHIMADZU [7].  In the free nicotinic acid molecule, the frequency of Valence oscillations of the pyridine ring increased from 1596 cm^-1, in the complex state up to 1632 cm^-1, while the CO bond valence oscillations of nicotinic acid [8] remained unchanged at 1709 cm^-1. ν_r(CСN) bond, on the other hand, can be seen decreasing to 1016 cm^-1. δ_(CCN) bond deformation vibration frequency in 755 cm^-1 decreased to 697 cm^-1 (Fig.1.)

Figure 1. IR spectrum of the complex compound [ZnHCONH₂∙NC₅H₄COOH∙(NO₃)₂]∙3H₂O

The formamide molecule CO bond valence oscillation frequency decreased from 1698 cm^-1 to 1687 cm^-1, while the ν_r(CN) bond's increased from 1306 cm^-1 to 1344 cm^-1. 1039 cm^-1 at v_s(NO3) strip [9], 1296 cm^-1 at intensive strip ν_as(NO3) expressed. In area 822 cm^-1, δ_(NO3) strip was observed. The difference in symmetric and asymmetric valence frequencies of the nitrate group is Δ_(ν3-ν1) 257, from which we can know that nitric acid residue is bidentant coordinated in the composition of the complex compound [10]. The water molecules located in the outer sphere of the complex compound, while ν_(OH) (H₂O) are visible in area 3243 cm^-1.

In the analysis of the composition of the complex compound, the HPLC (high-performance liquid chromatography) mass spectrometry method was used. The division was carried out at HPLC (Agilent Technologies -1260, USA) in a column with a rotating Phase 2,1x150 mm (3.5 µ) Eclipse XDB (Agilent Technologies, USA). Mass spectrometry of substances in the ESI ‒ mass spectrometry method (electrospray) mass spectrometer was obtained at 6420 Triple Quad APCI (Agilent Technologies, USA) [11].

In the mass spectrum of the complex [ZnHCONH₂∙NC₅H₄COOH∙(NO₃)₂]∙3H₂O, an ion with a mass of 411.2 m/z was recorded, corresponding to the mass of the complex compound (Fig.2.). The mass of the ion [ZnHCONH₂∙NC₅H₄COOH∙(NO₃)₂∙3H₂O+H] ⁺ is equal to 411.2.

Figure 2. Mass spectrometric data of the complex compound [ZnHCONH₂∙NC₅H₄COOH∙(NO₃)₂]∙3H₂O

Scheme 1. Fragmentation of the complex compound [ZnHCONH₂∙NC₅H₄COOH∙(NO₃)₂]∙3H₂O

From this ion m/z 358,4; 313,2; 296,3; 250,1; 173,2; 124,3 ions equal to the formed. This ions corresponding to the complex compound. [HNC₅H₄COOH] ⁺ (m/z=124,3) peak intensity was determined in the spectrum [12]. The decomposition of the complex compound into fragments and the molecular formula and masses of fragments are presented in Scheme 1.

Conclusion. The result of IR-spectroscopy shows that the complex compound contains nicotinic acid in a monodentate state through a nitrogen atom in the pyridine ring, while the formamide molecule, the CO bond, is coordinated with a zinc atom through an oxygen atom. Nitric acid anions, on the other hand, are bound to a zinc atom in a bidentate state. Water molecules, on the other hand, are located in the outer sphere. The zinc atom has an octahedron structure with ligands. Based on the analysis of mass spectrometry, it was found that the formed complex is decomposed into fragmented ions.

References:

1. Sharipova L.A., Azizov T.A., Ibragimova M.R., Turakulav J.U. Complex compound zinc nitrate with thiocarbamide and nitrocarbamide. The symposium ‘Khimiya v narodnom khazyaystve’ (= Chemistry in the national economy). Moscow. February 12, 2020.- P.102.
2. Sharipova L.A., Azizov T.A., Ibragimova M.R. Асetamide and nicotinic acid of моnotype ligand coordination compounds of zinc nitrate // Universum: chemistry and biology, - Moscow, 2021. 5 (83). - РP. 45-49.
3. Sharipova L.A. Synthesis, structure and properties of coordination compounds of zinc nitrate with homogeneous and mixed ligand ligands: PhD thesis in chemistry. Bukhara, 2022. – P.120.
4. Sharipova L.A., Azizov T.A., Ibragimova M.R. Thermal study of the coordination compound of zinc nitrate with nicotinic acid and benzamide // XIII International Symposium on the Chemistry of Natural Compounds.- October 16-19, 2019.- Shanghai.- Р. 200.
5. Charlot G. Methods of analytical chemistry. Quantitative analysis of inorganic compounds. - Moscow: Publishing house ‘Chemistry’. 1965. – P. 975.
6. Bazhenova L.N. Quantitative elemental analysis of organic compounds. - Yekaterinburg: 2008. – P. 356.
7. Nakamoto K. IR and Raman spectra of inorganic and coordination compounds. - Moscow: Mir, 1991. – P. 536.
8. Tarasevich B.N. IR spectra of the main classes of organic compounds. Reference materials – Moscow: MSU, 2012 – P. 54.
9. Sharipova L.A., Azizov T.A., Ibragimova M.R. Analysis of IR spectra of different coordination compounds of zinc nitrate with amides. The modern state and prospects of the science of Functional Polymers. Tashkent-2020. - P.384.
10. Sharipova L.А., Аzizov T.А., Ibragimova M.R. Coordination compounds zinc nitrate with urea, nitrourea and nicotinic acid //. Universum: chemistry and biology, -Moscow, 2018. №12(54). - PP. 45-49. URL: http://7uneversum/ru/nature/archive/item/6596
11. Zaikin V.G. Bases mass-spectrometry on the organic compounds. - Moscow: MAIK ‘Nauka. Interperiadika’. - 2001. - P. 286.
12. Yusupov V.G., Tashev M.T., Parpiev N.A. Chemistry of coordination compounds. Textbook Tashkent 1996. - P.282.