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Turakulov Jakhongir Ulugbekovich, Institute of General and Inorganic Chemistry of Uzbek Academy of Science E-mail: [email protected]
COMPLEX COMPOUNDS OF CALCIUM ACETATE WITH NITROCARBAMIDE
Abstract: synthesized homogeneous coordination compounds of calcium acetate with nitrocar-bamide. The composition, individuality, methods of coordination of acetate groups and the molecule of nitrocarbamide are established.
Keywords: coordination compounds, synthesis, IR spectroscopy, X-ray phase analysis, calcium acetate, nitrocarbamide.
Introduction. Rapid development of the chemistry of coordination compounds is due to their application in various fields. The coordination compounds of metals, possessing a number of specific properties, have found wide practical use in many branches of the national economy. For example, in the chemical technology of using multi-ligand coordination compounds is associated with the optimization of the separation processes of the components of the mixture. In analytical chemistry with the help of different ligand coordination compounds, it is possible to lower the detection limit and hang the selectivity of determining a large number of elements and substances. In biochemical systems, the synthesis ofsome different ligand coordination compounds can serve as models of processes occurring in living organisms. Molecules of nitrocarbamide (NTC) and anion of acetate acid (CH3COO-) 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. In the literature there is no information on homogeneous complex compounds of calcium acetate with nitrocarbamide.
Objects and methods of research. Synthesis, IR spectroscopy, X-ray phase analysis of homogeneous complex compounds of calcium acetate with nitrocarbamide are given. In the course of the pres-
ent study, calcium acetate was used for the synthesis of complex compounds of Ca(CH3COO)2-H2O composition of the "AR" or "R" type. As the ligands used nitrocarbamide (H2NCONHNO2) brand "AR".
To carry out the synthesis of coordination compounds, we chose the most effective mechanochem-ical method, since it does not require scarce organic solvents. The synthesis procedure was carried out according to [4].
Analysis of synthesized compounds for calcium content was carried out according to [5]. Nitrogen was determined by the Dumas method [6], carbon and hydrogen by burning in an oxygen flow [Table 1]. To determine the individuality of the synthesized compounds, radiographs were taken on a DRON-2.0 unit with a Cu-anticathode [7]. IR absorption spectra were recorded in the 400-4000cm-1 region on the AVATAP-360 spectrometer of Nicolet (Fig. 1-4).
The thermal analysis was carried out on the de-rivatograph of the Paulik-Paulik-Erdey system [6] at a rate of 10 deg / min and a 0.1 g sample with the sensitivity of the T-900, TG-100, DTA-1/10, DTG-1/10 galvanometers. The recording was carried out under atmospheric conditions with a constant removal of the gaseous medium by means of a water jet pump. The holder was a platinum crucible with a diameter of 7 mm without a cover. Al2O3 was used as a standard.
For the synthesis of complex compounds, we chose the most effective mechanochemical method, since it does not require scarce organic solvents [7].
The mechanochemical process of interaction of the initial components is carried out by intensive rubbing at room temperature in a ball mill of components taken in molar ratios of calcium acetate and carbamide 1: 2 and 1: 4, respectively. Similarly, all of the following compounds are shown in (Table 1).
In the synthesis of the complex compound
mol) of Ca(CH3COO)2-H2O was triturated from 4.2041 g (0.04 mol) of nitrocarbamide in a ball mill at room temperature for 0.3 hours. The yield of the product is 94.0%.
The compound of the composition Ca(CH3COO)2 • 4O2NHNCONH2-H2O was synthesized by mixing 1.7619g(0.01mol) of Ca(CH3COO)2 • H2O with 4.2013 g (0.04mol) of nitrocarbamide in a ball mill at room temperature in continuation 3 hours. The yield of the product is 96.0%.
Ca(CH3COO)2 • 2H2NCONHNO2, 3.5238g(0.02
Table 1.- Results of elemental analysis of homogeneous coordination compounds of calcium acetate with nitrocarbamide
Compounds Elements in percent
Mg,% N,% C,% H,%
Found Calculated Found Calculated Found Calculated Found Calculated
Ca(CH3COO)2-•2H2NCONHNO2 11.03 10.94 23.03 22.95 19.82 19.68 2.81 2.75
Ca(CH3COO)2--4H2NC0NHN02-H20 7.01 6.91 29.06 28.96 16.72 16.56 3.54 3.47
144.0. 140.
4000.0 3600 3200 2800 2400 2000
1600 1400 1200 1000
Figure 1. IR absorption spectrum of a homogeneous coordination compound of calcium acetate with nitrocarbamide - Ca(CH3COO)2 • 2H2NCONHNO2
130
120
110
100
%T
1554.33
20.0
400.0
Table 2.- Interplanar distances and relative intensities of calcium acetate lines, nitrocarbamide and their homogeneous complexes
Compounds d, Â I,% d, Â I,% d, Â I,% d, Â I,% d, Â I,%
16.94 6 4.42 22 3.15 20 2.25 12 1.779 10
15.19 8 4.35 22 3.09 24 2.22 6 1.747 8
12.96 6 4.21 37 3.07 22 2.20 16 1.721 6
10.12 6 4.11 8 3.00 16 2.15 29 1.687 12
8.89 27 4.06 18 2.92 45 2.09 10 1.651 8
7.73 100 4.02 24 2.85 12 2.06 18 1.637 10
Ca(CH3COO)2- 7.35 18 3.99 16 2.77 67 2.03 10 1.612 8
•2H2NCONHNO2 6.79 4 3.82 51 2.63 29 2.00 6 1.598 6
6.15 6 3.69 31 2.58 27 1.959 18 1.542 4
5.88 6 3.60 10 2.53 22 1.946 27 1.538 6
5.56 51 3.54 6 2.50 18 1.900 8 1.499 4
5.08 10 3.39 78 2.48 47 1.875 6
4.86 22 3.31 98 2.36 4 1.846 20
4.56 6 3.22 24 2.31 6 1.810 4
13.77 5 4.86 2 2.70 2 1.95 3 1.562 1
13.35 4 4.71 39 2.63 2 1.91 1 1.551 1
12.31 4 4.48 100 2.59 11 1.90 3 1.534 1
11.36 5 4.29 19 2.53 10 1.85 3 1.528 1
10.35 2 4.11 2 2.45 4 1.84 1 1.520 1
9.84 1 3.99 13 2.40 2 1.801 4 1.505 1
9.38 2 3.93 2 2.37 4 1.786 2 1.489 1
9.07 2 3.84 23 2.33 3 1.766 1 1.483 1
8.22 2 3.82 2 2.29 1 1.741 2 1.467 1
7.84 1 3.63 6 2.26 1 1.734 1 1.450 1
Ca(CH3COO)2--4h2nconhno2-h2o 7.50 2 3.55 3 2.22 1 1.717 1 1.440
7.23 2 3.51 3 2.20 6 1.701 1 1.426 1
6.93 2 3.48 3 2.18 8 1.687 1 1.419 1
6.64 3 3.40 3 2.15 4 1.664 2 1.415 1
6.36 2 3.34 1 2.12 1 1.653 2 1.406 1
6.13 2 3.28 17 2.10 2 1.647 2 1.401 1
5.96 1 3.18 33 2.09 1 1.633 1 1.387 1
5.85 1 3.08 25 2.07 2 1.627 1 1.383 2
5.67 2 3.04 5 2.06 2 1.612 1 1.371 1
5.52 2 2.94 8 2.03 1 1.600 1
5.32 1 2.87 2 2.02 1 1.595 1
5.20 2 2.82 4 2.00 2 1.585 3
4.97 1 2.75 3 1.96 10 1.570 1
Results and its discussion. Comparison of interplanar distances and relative intensities of calcium acetate monohydrate, nitrocarbamide and their complex compounds showed that the new homogeneous
coordination compounds differ from each other, as well as from the original components, hence the compounds have crystal lattices (Table 2).
In the infrared absorption spectrum of an uncoordinated molecule of nitrocarbamide, frequencies at 3437 - vas(NH2), 3352 - S(NH2), 3182 - v(NH2), 1704 - v(C==O), 1615 - S(NH2),V(CO), 1530 - vas (NO2), 1466 - v(CN), 1340 - vs (NO2), 1108 --p(NH2), 1027 - vs(CN), 785 - S(NH2), 543 --S(NCO). 8
The following frequencies were detected in the IR absorption spectrum of the complex compound Ca(CH3COO)2-2H2NCONHNO2: 3486, 3429,
3316, 3255, 3064, 2851, 2414, 1661, 1634, 1603, 1569, 1484, 1416, 1352, 1217, 1152, 1057, 1028, 946, 789, 726, 610, 534 and 434 cm-1 (Fig. 1).
The following frequencies were observed in the IR absorption spectrum of the complex compound Ca(CH3COO)24H2NCONHNO2^H2O: 3485, 3431, 3322, 3256, 2840, 1668, 1631, 1606, 1471, 1443, 1411, 1352, 1218, 1152, 1028, 981, 946, 789, 725, 610, 576 and 534 cm-1 (Fig. 2).
145.0 140.
2000 1800 1600 cm-1
Figure 2. IR absorption spectrum of a homogeneous coordination compound of calcium acetate with nitrocarbamide - Ca(CH3COO)2 • 4H2NCONHNO2 • H2O
Comparison of the IR absorption spectra of the free molecules of nitrocarbamide and their complex compounds with calcium acetate showed that with the transition to a coordinated position, the values of certain amide frequencies vary significantly. In the complex compounds of the compositions Ca(CH3COO)2 • 2H2NCONHNO2, Ca(CH3COO)2 4H2NCONHNO2 • H2O, the frequencies of the preferential stretching vibration of the C = O bond were 1726 cm-1, respectively. While the frequencies of stretching vibrations of the C-N
bond of the amide fragment were found at 1484 and 1471 cm1. These changes indicate the coordination of nitrocarbamide molecules through the oxygen atom of the carbonyl group. Water molecules are retained by the presence of hydrogen bonds.
On the heating curve of the compound Ca(CH3COO)2 • 2H2NCONHNO2, seven endo-thermic effects were found at 122, 195, 247, 317, 411, 527, 828 and two exothermic effects at 603 and 722 oC. The character of the subsequent thermal effects is accompanied by a stepwise decomposition
130.
120.
110.
100.
%T
30.0
4000.0
1400
1200
1000
400.0
of the anhydrous compound. In the temperature 2.35; 2.71; 3.53; 3.53; 7.06%. The total mass loss in
ranges 80-144, 144-240, 240-285, 285-356, 356- the temperature range 120-800 0C on the TG curve
474, 474-552, 552-660, 660-760, 760-860 oC, the is 66.23%, which corresponds to the formation of
weight loss is respectively 1.76; 15.29; 15.88; 14.12; calcium oxide.
AR rncj TG
t C
40
80
1Z0
160
200.
V 603 / A /
DTG \ ¡: V / 722
\ K / y 5 y/ w
- /4 /
DTA y 195 2 122 /
90C
S0C
700
eoc
síkü
-100
[HKl
ZOG 100
AP rnp TG
tuc.
25
50
75
100
10
BO
120
160
200
- OTG \ / '
_ \ -----: \ r^X......600 /
- ^ 473 ........... I // 740 774 / 363 /
"OTA as ' »V / 196 /
i i i
900
300
700
600
500
400
30C
200 100
25
SO
75
Time, inir
Time, min
10Û
a)
b)
Figure 3. Derivatograms: I-Ca(CH3COO)2-2H2NCONHNO2; II - Ca(CH3COO)24H2NCONHNO2-H2O
The heating curve of the complex compound Ca(CH3COO)2 • 4H2NCONHNO2 • H2O is characterized by seven endothermic effects at 85, 196, 239, 363, 473, 740, 774 0C and two exothermic effects at 535 and 600 0C. The appearance of the first endoeffect is due to the removal of the water molecule. The nature of other thermal effects is associated with a stepwise decomposition of the complex. The mass loss in the temperature range 60-126 °C is 3.04%; 3.02% is calculated. In the temperature ranges 126-204, 204-314, 314-405, 405-504, 504566, 566-660, 660-750, 750-790 0C the mass loss is 9.09; 27.27; 16.67; 8.59; 2.53; 1.21; 2.53; 2.40%, respectively. The total loss in the temperature range
of 60-790 °C on the TG curve is 73.23%, with the formation of calcium oxide.
The synthesis conditions have been developed, homogeneous calcium acetate compounds with nitrocarbamide are isolated in the solid state. The composition, individuality, ways of coordination of apical ligands and acetate fragments and thermal behavior are established. The structure of synthesized complex compounds of calcium acetate with nitrocarbamide is proposed. The new synthesized complexes can be used as stimulator in the cotton grows. The results obtained can be used as reference data for researchers working in the field of coordination chemistry.
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