American Journal of Technology and Applied Sciences ISSN (E): 2832-1766| Volume 11, | April, 2023 P a g e | 18 www.americanjournal.org MIXED LIGAND COORDINATION COMPOUNDS OF CALCIUM ACETATE WITH SOME ORGANIC LIGANDS Nurillayev Bunyodjon Khikmatilla ugli, Ismailov Akmal Aslanbekovich, Fayziyeva Aziza Komil kizi, Akhrorova Durdona Tulkin kizi, Turakulov Jakhongir Ulugbekovich Jizzakh Polytechnic Institute A B S T R A C T K E Y W O R D S Mixed-ligand coordination compounds of calcium acetate have been synthesized. The composition, identity, methods of coordination of acetate groups, molecules of formamide, acetamide, carbamide, thiocarbamide have been established, and the thermal behavior of the obtained complexes has been studied. Mixed-ligand coordination compounds, organic ligands, formamide, acetamide, urea, thiourea. Introduction Molecules of formamide (FA), acetamide (AA), urea (U), thiourea (TU) and acetic acid anion contain donor atoms and promote the formation of coordination compounds with metal ions. In [1-3], coordination compounds of a number of metal carboxylates with amides were synthesized and studied. There are no data on mixed-ligand coordination compounds of calcium acetate in the scientific literature. To carry out the synthesis of coordination compounds, we have chosen the most efficient mechanochemical method, since it does not require scarce organic solvents. The synthesis procedure was carried out according to [4, 5]. Complex compounds Ca(CH3COO)2·2FA·H2O, Ca(CH3COO)2·FA·AA·2H2O, Ca(CH3COO)2·FA·U·0.5H2O, Ca(CH3COO)2·FA·TU·2/3H2O obtained by intensive stirring in an agate mortar for 3 hours 0.01 mol of calcium acetate with 0.02 mol of formamide, 0.01 mol of calcium acetate with 0.01 mol of formamide and 0.01 mol of acetamide, 0.01 mol of acetate calcium with 0.01 mole of formamide and 0.01 mole of urea, 0.01 mole of calcium acetate with 0.01 mole of formamide and 0.01 mole of thiourea. The synthesized compounds were analyzed for calcium content according to [1-3]. Nitrogen was determined by the Dumas method [1-2], carbon and hydrogen were determined by combustion in an oxygen flow [Table 1]. To establish the individuality of the synthesized compounds, X-ray diffraction patterns were taken on a DRON-2.0 setup with a Cu anticathode [5]. IR absorption spectra were recorded in the region of 400-4000 cm-1 on AVATAP-360 spectrometer manufactured by Nicolet [Fig. 1]. American Journal of Technology and Applied Sciences Volume 11, April, 2023 P a g e | 19 www.americanjournal.org Thermal analysis was carried out on F-Paulik-J.Paulik-L.Erdey derivatograph system [6] at a rate of 9 deg/min and a weight of ~0.2 g at a sensitivity of T-900, TG-200, DTA, DTG galvanometers - 1/10. Recording was carried out under atmospheric conditions. A corundum crucible 10 mm in diameter without a lid served as a holder. Al2O3 was used as a control. Comparison of interplanar distances and relative intensities of calcium acetate, acetamide, carbamide (urea), thiocarbamide (tiourea) and complexes based on them showed that the new coordination compounds differ from each other, as well as from the original components, therefore, the compounds have an individual crystal lattice. Table 1. Results of elemental analysis of mixed-ligand coordination compounds calcium acetate Compounds Са, % N, % S, % C, % H, % Find. calc. Find. calc. Find. calc. Find. calc. Find. calc. Ca(CH3COO)2· ·2FА·Н2О 14,96 15,04 10,39 10,52 - - 26,88 27,07 5,24 5,30 Са(СН3СОО)2· ·FА·АА·2Н2О 13,51 13,39 9,43 9,36 - - 27,89 28,10 5,97 6,06 Са(СН3СОО)2·FА· ·U·0,5Н2О 14,81 14,68 15,51 15,44 - - 26,41 26,47 5,24 5,18 Са(СН3СОО)2·FА· ·TU·2/3Н2О 13,69 13,75 14,36 14,43 10,93 11,01 24,68 24,74 5,04 4,96 Frequencies (cm-1) at 3390, 3317-ν (NH2), 3194-2δ (NH2), 2888-ν (CH), 1709-ν (CO), 1615-δ (NH2), 1391-δ (CH), 1316-ν (CN), 1052-r (NH2), 604-δ (OCN). IR spectrum of distribution of free acetamide molecules by mass bands at 3378-ν (NH2), 3199-2δ (NH2), 1664-ν (CO), 1614-δ(NH2), ν (СО), 1395-ν (CN), 1352-δ (CH3), 1148-ρ (NH2), 1047-ρ (CH3), 1005-ν (CC), 575-δ (NCO) and 462-δ (CCN). In the IR absorption spectrum of a free urea molecule, frequencies were found at 3443- νas (NH2), 3347- νs (NH2), 3255- 2δ (NH2), 1679- ν (CO), δ (NH2), 1624- δ (NH2), ν (CO), 1464- ν (CN), 1152- , 1057- ρ (NH2), 1002- ν (CN), 789- δ (NH2), 573- δ (NCO) and 559- δ (NCN). The IR absorption spectrum of an uncoordinated thiocarbamide molecule has frequencies at 3380- νas (NH2), 3276- νs (NH2), 3178-2δ (NH2), 1619- δ (NH2), δ (HNC), 1474- ν (CN), 1413- ν (CS), 1084- ν (CN), 783- ρ (NH2), 730- ν (CS), 631- δ (CS), δ (NCS), 487- δ (NCN) and 413- δ (NCS). In the IR absorption spectrum of a free nicotinamide molecule, frequencies were found at 3366- ν (NH2), 3159- 2δ (NH2) 2, 3059- ν (CH), 1681- ν (CO), 1619- δ (NH2), 1593- νk, 1486, 1423- νk, δ (СNN), 1395-, 1340- ν (СH), δ (CCN), 1202- δ (CCN), 1154, 1124- ν (NH2), δ (CCN), 1091 - δ (CCN), ν (CO), νk, 1029- νk, δ (CCN), 970- ν (CC), 829- ν (CC), δ (CCC), 778, 703- δ (CCN), δ(CO), 624, 603-δ(CO), δ(CNC), 510-δ(CO), δ(CCC). An analysis of the IR absorption spectra of non-coordinated molecules of formamide, acetamide, urea and their complex compounds with calcium acetates showed that with the transition to coordinated positions, the values of some frequencies of amide molecules change significantly. Due to the complexity of the IR absorption spectra of complex compounds of calcium acetate with amides, we were unable to attribute all the observed frequencies to the corresponding vibrations of the bond groups. In the formamide complex compound of calcium acetate, the frequencies of the predominant stretching vibration of the C=O bond appear at 1692 cm-1. In mixed compounds American Journal of Technology and Applied Sciences Volume 11, April, 2023 P a g e | 20 www.americanjournal.org Ca(CH3COO)2·FA·AA·2H2O and Ca(CH3COO)2·FA·K· ·0.5H2O, the frequency ν (C=O) appears as total bands at 1673 and 1678 cm-1. While the frequencies of stretching vibrations of the C-N bond for formamide, acetamide and carbamide compounds increase by 32-65, 2 and 36 cm-1, respectively. In the mixed complex Ca(CH3COO)2·FA·TK·2/3H2O, the frequencies of the C=O and CN bonds of formamide appear at 1693 and 1348 cm-1. In the IR absorption spectrum of an uncoordinated formamide molecule, frequencies (cm-1) were found at 3390, 3317- ν (NH2), 3194- 2δ (NH2), 2888- ν (CH), 1709- ν (CO), 1615-δ (NH2), 1391-δ (CH), 1316-ν (CN), 1052-r (NH2), 604-δ (OCN). The IR absorption spectrum of a free acetamide molecule is characterized by bands at 3378- ν (NH2), 3199- 2δ (NH2), 1664- ν (CO), 1614- δ (NH2), ν (CO), 1395- ν (CN), 1352-δ(CH3), 1148-ρ(NH2), 1047-ρ(CH3), 1005-ν(CC), 575-δ(NCO) and 462-δ(CCN). In the IR absorption spectrum of a free urea molecule, frequencies were found at 3443- νas (NH2), 3347- νs (NH2), 3255- 2δ (NH2), 1679- ν (CO), δ (NH2), 1624- δ (NH2), ν (CO), 1464- ν (CN), 1152- , 1057- ρ (NH2), 1002- ν (CN), 789- δ (NH2), 573- δ (NCO) and 559- δ (NCN). The IR absorption spectrum of an uncoordinated thiourea molecule has frequencies at 3380- νas (NH2), 3276- νs (NH2), 3178-2δ (NH2), 1619- δ (NH2), δ (HNC), 1474- ν (CN), 1413- ν (CS), 1084- ν (CN), 783- ρ (NH2), 730- ν (CS), 631- δ (CS), δ (NCS), 487- δ (NCN) and 413- δ (NCS). In the IR absorption spectrum of a free nicotinamide molecule, frequencies were found at 3366- ν (NH2), 3159- 2δ (NH2), 3059- ν (CH), 1681- ν (CO), 1619- δ (NH2), 1593- νk, 1486, 1423- νk, δ (СNN), 1395-, 1340- ν (СH), δ (CCN), 1202- δ (CCN), 1154, 1124- ν (NH2), δ (CCN), 1091 - δ (CCN), ν (CO), νk, 1029- νk, δ (CCN), 970- ν (CC), 829- ν (CC), δ (CCC), 778, 703- δ (CCN), δ(CO), 624, 603-δ(CO), δ(CNC), 510-δ(CO), δ(CCC). An analysis of the IR absorption spectra of non-coordinated molecules of formamide, acetamide, urea and their complex compounds with calcium acetates showed that with the transition to coordinated positions, the values of some frequencies of amide molecules change significantly. Due to the complexity of the IR absorption spectra of complex compounds of calcium acetate with amides, we were unable to attribute all the observed frequencies to the corresponding vibrations of the bond groups. In the formamide complex compound of calcium acetate, the frequencies of the predominant stretching vibration of the C=O bond appear at 1692 cm-1. In mixed compounds Ca(CH3COO)2·FA·AA·2H2O and Ca(CH3COO)2·FA·K·0.5H·O, the frequency ν (C=O) appears as total bands at 1673 and 1678 cm-1. While the frequencies of stretching vibrations of the C-N bond for formamide, acetamide and carbamide compounds increase by 32-65, 2 and 36 cm-1, respectively. In the mixed complex Ca(CH3COO)2·FA·TK·2/3H2O, the frequencies of the C=O and CN bonds of formamide appear at 1693 and 1348 cm-1. In the low-frequency region of the spectrum, the frequencies of thiocarbamide molecules at 730 and 631 cm-1 decrease by 30 and 10 cm-1 in the case of the complex. In the low-frequency region of the spectrum, the frequencies of thiocarbamide molecules at 730 and 631 cm-1 decrease by 30 and 10 cm-1 in the case of the complex. The found changes in the spectrum can be explained by the coordination of the thiocarbamide molecule with the calcium ion through the sulfur atom. American Journal of Technology and Applied Sciences Volume 11, April, 2023 P a g e | 21 www.americanjournal.org Fig. 1. IR absorption spectra: a - Ca(CH3COO)2·2FA·H2O, b - Ca(CH3COO)2·FA·AA·2H2O, c - Ca(CH3COO)2·FA·K·0.5H2O and d - Ca(CH3COO)2·FA·TK·2/3H2O. А b c d а American Journal of Technology and Applied Sciences Volume 11, April, 2023 P a g e | 22 www.americanjournal.org The value of the frequency difference νas (COO)- νs (COO) of all compounds is less than 150 cm-1, which corresponds to the bidentate-cyclic coordination of the acetate fragment. In complex compounds, the central ion has a six-coordination site. Water molecules are held together by hydrogen bonds. The thermal study of the synthesized complex compounds showed that the DTA curves of the derivatograms revealed endothermic effects corresponding to the removal and decomposition of bound and coordinated molecules of water, formamide, acetamide, urea, and thiourea, as well as exothermic effects due to the destruction of acetate fragments, combustion of thermal decomposition products, and oxide formation or calcium sulfide. REFERENCES 1. Ulugbekovich, T. J., Pulatovna, N. K., Aslanbekovich, I. A., & Mamajonovna, T. F. (2023). Coordination Compounds Of Calcium Acetate With Some Ligands. Texas Journal of Engineering and Technology, 18, 12-18. 2. Ulugbekovich, T. J., & Pulatovna, N. K. ELECTRONIC STRUCTURES AND REACTIVITY OF EIGHT MIXED-LIGAND COMPLEXES OF CALCIUM ACETATE BY A QUANTUM- CHEMICAL METHOD. HOMO, 10(9,655), 8-918. 3. Turakulov Jakhongir Ulugbekovich (2018). Complex compounds of calcium acetate with nitrocarbamide. 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