SYNTHESIS AND STRUCTURE OF COMPLEX COMPOUNDS OF Mn(II), Ni(II), Cu(II), Zn(II) IONS WITH BENZOYLHYDRAZONE PARA-[BIS-1,4-(4,4,4-TRIFLUROBUTNDIONE-1,3)]BENZENE

ABSTRACT

In this article, we studied the structure of complex compounds formed by Mn(II), Ni(II), Cu(II), Zn(II) ions with a tridentate ligand - para-[bis-1,4-(4,4,4-triflurobutndione-1,3)] benzene benzoylhydrazone, containing N,O,O-donor atoms. The liquefaction temperature of the synthesized substances was determined and the results of elemental analysis were obtained. Based on UV and IR spectroscopy data, the presence of the ligand in various tautomeric forms was analyzed.

АННОТАЦИЯ

В данной статье мы изучили строение комплексных соединений, образованных ионами Mn(II), Ni(II), Cu(II), Zn(II) с тридентатным лигандом - пара-[бис-1,4-(4, 4,4-трифторбутндион-1,3)]бензол бензоилгидразон, содержащий N,O,O- донорные атомы. Определена температура сжижения синтезированных веществ и получены результаты элементного анализа. На основании данных УФ- и ИК-спектроскопии проанализировано наличие лиганда в различных таутомерных формах.

Keywords: UV and IR spectroscopy, N,O,O-donor atoms, β- diketone, di-β-diketone, intramolecular hydrogen bond, polycarbonyl compound, acyl and thioacylhydrazones, complex compounds.

Ключевые слова: УФ- и ИК-спектроскопия, N,O,O-донорные атомы, β-дикетон, ди-β-дикетон, внутримолекулярная водородная связь, поликарбонильное соединение, ацил и тиоацилгидразоны, комплексные соединения.

Introduction

Research in the field of complex compounds of acyl and thioacylhydrazones of polycarbonyl compounds with intermediate metals is actively developing in modern coordination chemistry. The importance of such complex compounds lies in the fact that they are used in various fields of industry and technology, for example, metal complexes in catalytic processes, polymerization, hydrogenation, carbonization, production of molecular electronics and magnetoactive materials. Fluorinated β-diketones, di-β-ligands based on diketones and their complexes are also widely used [1-2]. They are used in agriculture as biological stimulants, fungicides and antibacterial agents, in medicine, in the treatment of cancer, in industry as catalysts, in the quantitative analysis of rare earth metals and in the process of quantitative gas chromatographic determination of their composition [1-3]. In addition, fluorinated N-N0-ethylene-bis-β-aminoenones are used as effective organic optical filters in opening coatings by precipitation of metal-organic chemical vapors [1,8,9]. V. I. Filyakova, Ye. Studies by F. Xmara, V. N. Charushins have suggested the use of fluorinated lithium di ketones to synthesize bis-enaminosetones containing several independent coordination centers [3, 5].

Ekaterina F. Zhilina, Dimitri L. Chizhov and others. synthesized by the interaction of the tetra nuclear complex compound. The authors synthesized the 2,6-di(5-trifluoromethylpyrazol-3-yl)pyridine: Cu(II) complex, studied the properties of the complexes and their transformation with selected azaligands. As a result of the reaction of the resulting complex compound with py, 2,2`-bpy, tpy, tppz, 4,4`-bpy, DABCO [Cu(L)py₂], [Cu(L)(2,20-bpy)], [Cu(L)₂(tppz)] THF, [Cu(L)tpy]C₆H₅CN, and coordination polymers {[Cu₂(L)₂(4,40-bpy)₂] (C₆H₅CH₃)-MeCN}_n; {[Cu(L)DABCO]₂MeCN}_n. Obtained compounds were characterized by IR spectroscopy, X-ray diffraction, EPR and SQUID magnetic measurements [4]. 

In [5] it was considered When heated in glacial acetic acid (or ethanol in the presence of manganese(II) acetate, 3-amino-4,4,4-trifluoro-1-phenylbut-2-en-1-one undergoes an unusual transformation into 2,6-diphenyl-4-trifluoromethylpyridine. Regio isomeric b-aminol ketone, i.e. 1-amino-4,4,4-trifluoro-1-phenylbut-1-en-3-he remains unchanged in a similar reaction terms.

In [6] it was considered in this work, we present two new mononuclear complex compounds obtained by the reaction of Bzpy with Cu(II) and Co(II) salts: The Cu(II) molecular complex and the ionic type Co(II) complex [Cu(Bzpy)₂(Cl)₂] and [Co(Bzpy)₂(H₂O)₂] (BF₄)₂. At the same time, a Cu(II) compound of the same composition [Cu(Bzpy)2(Cl)2], which is a polymorph of compound I, was found in.

The main part

Due to the introduction of strong electronegative substituents, such as fluorine, into the molecule, a number of properties of the complexes are improved. Increases the stability of the molecule and reduces the tendency to polymerize. The acidity of both the initial ligands and the complexes increases upon fluorination. Often, specific intermolecular interactions occur with the participation of fluorine atoms [2]. As a result of ligand – para-[bis-1,4-(4,4,4-triflurobutndione-1,3)] benzene benzoylhydrazone interaction with Ni(II), Cu(II), Zn(II), Mn(II) ions in a ratio of 1: 2, homo binuclear complexes are formed. A NH₃ solution of metal acetates was used for the reaction, resulting in the synthesis of complex compounds Ni₂L·2NH₃, Cu₂L·2NH₃, Zn₂L·2NH₃, Mn₂L·2NH₃.

Synthesis of para-[bis-1,4-(4,4,4-trifluorobutanedione-1,3)]-benzene aryl hydrazone. In a 500 ml round bottom flask, pre-measured 0.01 moll (0.354 g) of para-[bis-1,4-(4,4,4-trifluorobutanedione-1,3)]-benzene, 100 ml of absolute isopropyl alcohol are added. An inverted cooler is placed in the flask, fixed on a support, and the mixture is heated on a water bath until a homogeneous solution is formed. Take a beaker with a capacity of 150 ml, measure out 0.02 moll (2.72 g) of benzoic hydrazide and stir with a glass rod until it is completely dissolved in 50 ml of isopropyl alcohol. The solution in the beaker is poured into the flask and a reflux condenser is installed. A magnetic stirrer is used to continuously stir the reaction mixture. Boil in a water bath for 3 hours and leave for 3 days. Then the resulting precipitate – benzoyl hydrazone para-[bis-1,4-(4,4,4-trifluorobutanedione-1,3)]-benzene is filtered on a Schott funnel and washed several times with isopropyl alcohol, and then with air-dry distilled water. Yield - 84%; 5 g.

In the same way, a solution of benzoyl hydrazone para-[bis-1,4-4,4,4-trifluorobutandion-1,3]-benzene and zinc acetate, nickel acetate and manganese acetate, copper acetate in ammonia was mixed in a 1:2 ratios, homobinuclear complex compounds containing Zn₂L^.2NH₃, Ni₂L^.2NH₃, Mn₂L^.2NH₃, Cu₂L^.2NH₃ were synthesized. The resulting metal complexes dissolve well in methanol at room temperature when slightly heated in ethanol and are poorly soluble in benzene and chloroform. The yield of the reaction and the results of the element analysis are given in Table 1.

Table 1.

Productivity of synthesized substances and results of element analysis

Regardless of the tautomeric structure of the ligand, when they interact with metal acetates, complex compounds M₂L·2NH₃ are formed, in which the ligand becomes a ring-chain tautomer and is deprotonated four times. During the formation of the complex, there happens the regeneration of the linear rehydration (IIA) in the ligand (oxyazine - yenhidrazine) which is in the form of the cyclic 5-hydroxy-2-pyrazoline (IIB).

IR spectra from samples of synthesized substances on the instrument of IRTracer-100 (SHIMADZU CORP., Japan, 2017) recorded signals in the area of 400-4000 cm^-1 using the MIRacle-10 diamond / ZnSe prism. The following oscillation frequencies were recorded in the IR spectrum of the benzoyl hydrazone para- [bis-1,4- (4,4,4-trifluorobutandion-1,3)]-benzene molecule: The valence oscillation frequency of the C-H bond is (C-H) 3124 cm^–1, The valence oscillations of the carbon-oxygen bond in the enol fragment n (CO) 2360 cm^–1, the oscillation frequencies in the area ν C=O) 1558 cm^–1 to the carbonyl group indicate the presence of a free C=O group adjacent to CF₃. Frequency signals of bending vibrations of O-H bonds in the enol fragment were observed in the region d_w(O-H)=1456 cm^-1. Of the bond adjacent to the aromatic ring in area ν_s =1240 cm^–1, C-C bond-specific valence oscillations in the aromatic ring 1199 cm^–1, 1105 cm^–1, 1074 cm^–1 fields, stretching vibrations associated with the C-F bond were registered in the regions ν (C-F) 1016 cm^-1, 814 cm^-1 and 798 cm^-1. Also, C-F dw (C-F) = 690 cm^–1, 582 cm^–1, 503 cm^–1 (Figure 1).

Based on IR spectral data, the presence of an intramolecular hydrogen bond in the benzoyl hydrazone para- [bis-1,4-(4,4,4-trifluorobutandion-1,3)]-benzene molecule was proved [4, 5,6,7,8].

The composition and structure of the organic ligand were determined by element analysis and UV and IR spectroscopy. The absorption frequency n (C=O) in the 1558 cm^–1 region of the IR spectrum of the synthesized ligand proves the presence of a free C=O group adjacent to CF₃. In the spectrum, the valence oscillations of the ν_(N-H bond appear in the 3440 cm^–1 region, and in the high frequency 3267 cm^–1 region, hydrazine fragment's the oscillation lines n_s, n_as  characteristic of the N-H. Deformation oscillations' signals of the C-F bond were recorded in the area of  (d_w) 738-603 sm^–1 (Figure 1) [10,11].

Figure 1. IR spectrum of benzoyl hydrazone para- [bis-1,4- (4,4,4-trifluorobutandion-1,3)] - benzene molecule

Valence oscillations which are specific to Zn-N and Zn-O in the 609-536 cm^–1 region in the IR spectrum of Zn(II) complex synthesized on the basis of benzoyl hydrazone para-[bis-1,4-(4,4,4-triftorbuandion-1,3)]-benzene confirm that the ligand is in coordination with the nitrogen and oxygen atoms. The specific absorption of the NH₃ molecule, coordinated in area 3404-3342 cm^–1, confirms the flat-square structure of the molecule (Figure 3) [11-12].

Figure 2. IR spectrum of benzoyl hydrazone para-[bis-1,4- (4,4,4-trifluorobutandion-1,3)] - benzene Zn (II) complex compound

Benzoyl hydrazone para-[bis-1,4-(4,4,4-trifluorobutandion-1,3)]-benzene molecule contains four potentially moving protons. The fact that the IR spectrum of the complex formed by the ligand with the ion Zn(II) does not contain signals specific to group ν_(C=O) proves our point. Moreover, the intense signals of NH₃ molecules coordinated in the 3404 and 3342 cm^–1 domain and the appearance of the Zn-O bonds' signals in the 609-536 cm^–1 regions prove once again that our idea is correct.

Figure 3. IR spectrum of benzoyl hydrazone para-[bis-1,4- (4,4,4-trifluorobutandion-1,3)] – benzene Cu (II) complex compound

Benzoyl hydrazone para-[bis-1,4- (4,4,4-trifluorobutandion-1,3)]-benzene gave signals in the ν_(C=N) 1456 cm^–1 region of the valence oscillations of the C=N bond in the IR spectrum. The shift of the Cu(II) complex compound of this ligand to a weak field in the IR spectrum N=C-C=N  (1432 sm^–1) 24 sm^–1 confirms that the amide and di ketone parts of the molecule are coordinated with two oxygen atoms, as well as the metal ion of the nitrogen atom azo methyl.

While being analyzed the IR spectrum of benzoyl hydrazone para-[bis-1,4- (4,4,4-trifluorobutandion-1,3)]-benzene gave signals in the complex compounds Ni(II) and Mn(II), Intensive valence oscillation frequencies of metal oxygen bonds and the coordinated ammonia molecule were recorded in the areas 582cm^-1 as well as 600 cm^-1 and 3350-3340 cm^-1 respectively. (Table2)

Table 2.

Basic oscillation frequencies in the IR spectra of the obtained substances (cm^-1)   

To study the optical properties of the synthesized substances, UV spectra were obtained from their solutions in obsolete ethanol. In the analysis of the obtained UV spectra, the absorption maxima of the starting material specific to the C=O carbony group were recorded at 254 nm and the signals corresponding to the aromatic ring at 338, 358, 382 nm. Batachronic displacement was caused by chromophore groups in the acltylthiosemicarbazone molekule formed by two renewed (enolated) oxygen atoms of the tetracarbonyl compound and a thiosemicarbazide molekule, which was confirmed by spectral analysis data [10-12].

Conclusion. Synthesis of aryl hydrazides of fluorinated polycarbonyl compounds allows to obtain new coordination compounds. Over the next decade, the synthesis of 3D metal complexes has been further developed, with the help of fluoridation of β-bis-diketones, their volatility and stability, the acidity of ligands and complexes increases. The tendency to polymerization is reduced. The obtained substances were studied by physical research methods using UV and IR spectroscopy and we proved the flat quadratic structure of the molecule by matching the complex compounds M₂L^.6NH_3, M₂L^.2NH₃ to the general formula and recording the valence oscillations specific to the ammonia molecules coordinated in the IR spectra.

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