Synthesis and research of new complex compounds of rare earth element nitrates with N-methylglycolurils Текст научной статьи по специальности «Химические науки»

Tomsk State University Journal of Chemistry, 2023, 32, 62-74

Original article UDK 547.785 / 546.65 doi: 10.17223/24135542/32/5

Synthesis and research of new complex compounds of rare earth element nitrates with N-methylglycolurils

Alexey Nikolaevich Guslyakov1, Yulia Dmitrievna Razgulyaeva2, Pana Dauletovna Turebaeva3, Abdigali Abdimanapovich Bakibaev4, Rakhmetulla Sharapidenovich Yerkasov5

12,4 Tomsk State University, Tomsk, Russia 3'5 L.N. Gumilyov Eurasian National University, Astana, Kazakhstan 1 guslyakov. aleksej@bk. ru 2 yuliya-razgulyaeva@rambler.ru

3 pana90@mail.ru

4 bakibaev@mail.ru 5 erkass@mail. ru

Abstract. A series of new complex compounds of nitrates of trivalent rare earth elements (lanthanum, cerium, praseodymium, neodymium, samarium, terbium, dysprosium, erbium, ytterbium) with bicyclic bisureas - N-methylglycolurils (N-monomethyl-glycoluryl, 2,4-N-dimethylglycoluryl, 2,6-N-dimethylglycoluryl, 2,4,6,8-N-tetra-methylglycoluryl) as ligands were obtained. IR spectroscopy showed that the rare earth elements (REE) ions are coordinated by two oxygen atoms of two N-methylglycoluryl molecules, three bidentate nitrate anions, and water molecules. N-methylglycolurils realize bidentate, chelating, and bridging functions and tend to form binuclear complexes with rare earth elements. Mass spectrometry with an inductively coupled plasma of synthesized complexes was carried out, and the metal:ligand ratio was ~1:1, respectively. Powder X-ray diffraction allowed us to establish the structures of complex compounds of 2,4,6,8-N-tetramethylglycoluryl with cerium, neodymium, terbium, and dysprosium nitrates. NMR spectroscopy of the obtained complexes was also performed in DMSO-d6 to detect a complex particle in the solution. The resulting complexes are stable in air, however, they are sensitive to trace amounts of water in the solution and are prone to degradation into their original substances.

Keywords: methylglycoluril, rare-earth elements, complex compound, bicyclic bisurea, X-ray diffraction, IR

Acknowledgments: The study was carried out with the support of the Tomsk State University Development Program (Priority-2030).

For citation: Guslyakov A.N., Razgulyaeva Yu.D., Turebaeva P.D., Bakibaev A.A., Yerkasov R.Sh. Synthesis and research of new complex compounds of rare earth element nitrates with N-methylglycolurils. Vestnik Tomskogo gosudarstvennogo universiteta. Chimia - Tomsk State University Journal of Chemistry, 2023, 32, 62-4. doi: 10.17223/24135542/32/5

© A.N. Guslyakov, Yu.D. Razgulyaeva, P.D. Turebaeva et al., 2023

Научная статья

10.17223/24135542/32/5

Синтез и исследование новых комплексных соединений нитратов редкоземельных элементов с К-метилгликолурилами

Алексей Николаевич Гусляков1, Юлия Дмитриевна Разгуляева2, Пана Даулетовна Туребаева3, Абдигали Абдиманапович Бакибаев4, Рахметулла Шарапиденович Еркасов5

1,2, з, 4 Томский государственный университет, Томск, Россия 5Евразийский национальный университет им. Л.Н. Гумилева, Астана, Казахстан

1 guslyakov. aleksej@bk. ги 2 yuliya-гazgulyaeva@гambleг. ги

3 рапа90@таИ. ги

4 bakibaev@mail. ги 5 erkass@mail.ru

Аннотация. Получен ряд новых комплексных соединений нитратов трехвалентных редкоземельных элементов (лантана, церия, празеодима, неодима, самария, тербия, диспрозия, эрбия, иттербия) с бициклическими бимочевинами -Ы-метилгликолурилами в качестве лигандов (Ы-монометилгликолурил, 2,4-Ы-ди-метилгликолурил, 2,6-Ы-диметилгликолурил, 2,4,6,8-Ы-тетраметилгликолурил). ИК-спектроскопия показала, что ионы редкоземельных элементов (РЗЭ) координируются двумя атомами кислорода двух молекул Ы-метилгликолурила, трех би-дентатных нитрат-анионов и молекулами воды. Ы-метилгликолурилы реализуют бидентатную, хелатирующую и мостиковую функции и склонны к образованию биядерных комплексов с редкоземельными элементами. Проведена масс-спек-трометрия с индуктивно-связанной плазмой синтезированных комплексов, соотношение металл: лиганд составило ~ 1:1. Методом порошковой рентгеновской дифракции установлено строение комплексных соединений 2,4,6,8-Ы-тетраме-тилгликолурила с нитратами церия, неодима, тербия и диспрозия. ЯМР-спектро-скопию полученных комплексов проводили в ДМСО-(1б для обнаружения комплексной частицы в растворе. Образующиеся комплексы устойчивы на воздухе, однако чувствительны к следовым количествам воды в растворе и склонны к распаду до исходных веществ.

Ключевые слова: метилгликолурил, редкоземельные элементы, комплексное соединение, бициклическая бимочевина, рентгеноструктурный анализ, ИК

Благодарности: Исследование выполнено при поддержке Программы развития ТГУ («Приоритет-2030»).

Для цитирования: Гусляков А.Н., Разгуляева Ю.Д., Туребаева П.Д., Бакибаев А.А., Еркасов Р.Ш. Синтез и исследование новых комплексных соединений нитратов редкоземельных элементов с Ы-метилгликолурилами // Вестник Томского государственного университета. Химия. 2023. № 32. С. 62-74. (1о1: 10.17223/24135542/32/5

Introduction

Bicyclic bisureas, particularly glycolurils, due to the polyfunctionality of their structure, have found a wide range of applications in various spheres of human activity. Currently, there are several important substances and materials are manufactured based on glycoluryl and its derivatives on an industrial scale, including medicines [1], crosslinking agents for the production of special-purpose polymers [2, 3], activators of peroxide compounds for bleaching [4], disinfectants [5, 6], independent explosives or their components [7, 8], etc.

However, the coordination compounds of bicyclic bisureas have not been practically studied. This is explained by the fact that only those compounds in which bicyclic bisurea has a set of valuable biological properties are of interest [9]. Additionally, structural N-methyl homologues of glycoluryl lack specific biological activity, further limiting the research focus in this area.

Among the ligands containing the glycoluryl fragment, 2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione, also known as mebikar (Mb) (Fig. 1e) (C8H14N4O2), has been extensively studied. The particular interest in mebikar is primarily due to its valuable physiological properties [10-13].

Previously, A.Y. Tsivadze and his colleagues reported a number of complex compounds based on mebikar, including [CotMb^^O^B^^O, [Ni(Mb)2(H2O)2Br2], [NiMb(H2O)4](NO3)2, and [Cu2(Mb)3Br4>2H2O, CdCh- Mb-3ftO, CaCk^Mb-^O, Co(NO3)2-2Mb-4H2O, Ni(NO3)2-Mb-4H2O, CdX2-Mb (X = Br, I, N, C, S), Cd(NO3)2-1.5Mb-H2O, ZnCl2-Mb, Znl2-Mb, Ca(NO3)2-2Mb, Cu(NO3)2-0.5Mb, [Li2(Mb)2(H2O)4]Br2 [14, 15]. These compounds were characterized by elemental analysis, IR and RAMAN spectroscopy, and in some cases, X-ray diffraction. The studies showed that Mb is coordinated to the metals through oxygen atoms of urea fragments, which was confirmed by a decrease in the frequency of oscillation of amide-I and an increase in the frequency of deformation vibrations of methylamine groups. Later, E. E. Netreba obtained and characterized complexes with mebicar composition: [MnMb(NO3)2]2, [SmMb(H2O)2(NO3>]2, [GdMb(H2O)(NO3>]2-H2O, [Eu(Mb)2(NO3)3]2, [PrmB(H2O)2(NO3)3]2 using data from elemental analysis, IR spectroscopy, X-ray diffraction [16-20].

However, there is no information in the literature about the existence of complex compounds of other N-methylglycolurils such as N-monomethylglycoluryl (C5H8N4O2, 2-methyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione, MeGl) (Fig. 1b), 2,4-N-dimethylglycoluryl (2,4-dimethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione, C6H10N4O2, 2,4-Me2Gl) (Fig. 1c), 2,6-N-dimethylglycoluryl (2,6-di-methyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione, C6H10N4O2, 2,6-Me2Gl) (Fig. 1d), as well as their coordinating ability with nitrates of rare earth elements.

Due to the non-planar spatial structure of N-methylglycoluriles in the form of a half-open book, they can act as bidentate ligands with a bridging function.

N-methylglycolurils display ambidentate ligand behavior, acting as a rigid Lewis base. This characteristic provides motivation to investigate their complexing properties, which allows us to get a complete understanding of the chemistry of the interaction of bicyclic bisureas with lanthanide ions, and to find out the dentacy of ligands.

Fig. 1. Structural formulas of glycoluryl (1a), momnomethylglycoluryl (1b), 2,4-dimethylglycoluryl (1 c), 2,6-dimethylglycoluryl (1d), mebicar (1e)

Rare earth metal salts and their complex compounds are used as effective catalysts for dienespolymerization and copolymerization. 2-Ethylhexyl neodymium phosphate is used for the polymerization of isoprene [21].

In connection with the above, this work aims to synthesize and determine the structure of previously unknown complex compounds of rare earth element nitrates with N-methylglycoluryl and water molecules.

Materials and methods

Crystallohydrates of REE nitrates were obtained by the method [22]. Suspension of oxides (PrO2, Nd2O3, SmO, Tb4O7, Dy2o3, Er2O3, Yb2O3) or lanthanum carbonate (La2(CO3)3) introduced into nitric acid, heated to dissolution, evaporated the solution to a syrupy state, and the crystals are formed by cooling. The crystals were filtered using a Buchner funnel and then dissolved in distilled water for recrystallization. Recrystallization was carried out twice, resulting in newly obtained crystals which were filtered and dried in air.

N-monomethylglycoluryl (MeGl) was obtained by condensation of 4,5-dihydro-xyimidazolidinone-2 with methyl urea pH=1-2 at 90°C with a yield of 36.3% [23]. The NMR 1H spectra (DMSO-d6, TMS) 5 showed the following signals, ppm: 2.60 3H (c, CH3), 5.14 1H (d, CH), 5.19 1H (d, CH), 7.20 1H (c, NH), 7.30 2H (c, NH). The NMR 13C spectra (DMSO-d6, TMS) 5 showed signals at ppm: CH3-, C-H, and C=O 27.56 ppm, 62.54 and 69.89 ppm, 159.75 and 161.79 ppm, respectively.

2,4-N-dimethylglycoluryl (2,4-Me2Gl) was obtained by condensation of 4,5-di-hydroxyimidazolidinone-2 with dimethyl urea pH=1-2 at 90°C with a yield of

46.8% [24]. The NMR 1H spectra (DMSO-d6, TMS) 5 showed signals at ppm: 2.64 6H (c, CH3), 5.12 2H (c, CH), 7.54 2H (c, NH). The NMR 13C spectra (DMSO-d6, TMS) 5 showed signals at ppm: CH3-, C-H, and C=O 28.22 ppm, 76.67 ppm, and 158.22 and 160.20 ppm, respectively.

2,6-N-dimethylglycoluryl (2,6-Me2Gl) was obtained by condensation of methyl urea with glyoxal pH=1-2 at 90°C with a yield of 44%. NMR 1H spectra (DMSO-d6, TMS) 5 showed signals at ppm: 2.78 6H (c, CH3), 5.17 1H (d, CH), 5.19 1H (d, CH), 7.40 2H (c, NH) (cis isomer); 2.61 6H (c, CH3), 5.10 2H (c, CH), 7.56 2H (c, NH) (trans-isomer), whereas NMR 13C spectra (DMSO-d6, TMS) 5, showed signals at ppm: CH3-, C-H and C=O cis isomers (26.69 ppm; 60.63 and 75.63 ppm; 160.19 ppm, respectively) and trans-isomers (27.44 ppm, 67.37 ppm, and 159.61 ppm) [24].

2,4,6,8-N-tetramethylglycoluryl (Mb) was obtained by condensation of dimethyl urea with glyoxal pH=1-2 at 90°C with a yield of 57.3%. The product was identified by the melting temperature (Tpl = 226-228°C). The NMR 1H spectra (DMSO-d6, TMS) 5 showed peaks at ppm: 2.82 12H (s, CH3), 5.06 2H (s, CH). And the NMR 13C spectra (DMSO-d6, TMS) 5 showed signals at ppm: CH3-, C-H, and C=O 30.44 ppm, 71.92 ppm, and 159.05 ppm, respectively. The data obtained are consistent with the literature [25].

The IR spectra of the initial substances and the obtained complexes were recorded using a Nicolet 6700 IR Fourier spectrometer with the prefix NPVO on a diamond crystal with a resolution of 4 cm-1, 64 scans, a range of 350-4500 cm-1.

Powder X-ray diffraction (XRD) analysis was performed on an XRD-7000 X-ray diffractometer (Shimatdzu, Japan) with CuKa radiation, X = 1.54073 A, range 3-50 v 20, measurement speed 3°/min.

Inductively coupled plasma mass spectrometry (ICP-MS) was performed on a Nexion 300 Series ICP Ms device.

NMR analysis was performed using a Bruker AVANCE 400 III HD NMR spectrometer (Bruker, Billerica, MA, USA). One-dimensional spectra were taken on the nuclei of atoms 1H (frequency 400.17 MHz) and 13C (frequency 100.63 MHz) to confirm the structure. DMSO-d6 was used as a solvent.

Results and discussion

The general method of synthesis of complex compounds I-XXXIV

A sample of nitrate hexahydrate of the corresponding rare earth element (0.8 mmol) was dissolved in a glass containing 5 mL of acetone. Then, a portion of the corresponding N-methylgltcoluryl (0.001 mol) was added and mixture was stirred on a magnetic stirrer for 10 minutes. The resulting solution was filtered, the glass was covered, and left for a day for the precipitate to settle. The resulting precipitates were filtered out, washed three times with 5 ml portions of acetone, and dried in air. The yields (based on ligand) are presented in Tables 1-4. The I-XXXIX complexes are stable in air, limitedly soluble in most organic solvents, and decompose into original substances in water, DMSO, and alcohol. In solution, the synthesized complexes are sensitive to the presence of trace amounts of water.

Table 1

Characteristic data for complexes I - IX with monomethylglycoluryl

№ Metal CC Output % MeGl ICP-MS REE/MeGl

0=C<, cm-1

Urea, 1 743 cm-1 A, cm-1 MeUrea, 1 685 cm-1 A, cm-1

I La 29 1 701 42 1 671 14 0.97 1

II Ce 30 1 698 45 1 668 17 0.89 1

III Pr 25 1 688 55 1 652 33 0.94 1

IV Nd 27 1 687 56 1 651 34 0.93 1

V Sm 26 1 689 54 1 646 39 0.95 1

VI Tb 23 1 700 43 1 650 35 0.99 1

VII Dy 16 1 685 58 1 656 29 0.92 1

VIII Er 24 1 670 73 1 646 39 0.91 1

IX Yb 20 1 618 25 1 673 12 0.90 1

In the IR spectra of synthesized complexes I-IX, in comparison with MeGl, there is a shift of the absorption bands corresponding to the valence vibrations of both carbonyl groups (O=C<) to the long-wavelength region, which indicates the coordination of MeGl molecules through the oxygen atoms of urea fragments. Additionally, wide absorption bands vs+as (HOH) 3550-3300 cm-1 and groups of absorption bands of MeGl rings are observed in the spectrum.

ICP-MS of the synthesized complexes revealed the content of the rare earth element in the samples, tables 1 -4 present the molar ratios of the rare earth metal to the ligand. The data obtained are consistent with the literature reports indicating that the ratio of mebikar to rare earth metal is 1:1 [17-21].

Table 2

Characteristic data for X - XVIII complexes with 2,4-dimethylglycoluryl

№ Metal CC Output % 2,4-Me2Gl ICP-MS REE/2,4-Me2Gl

0=C<, cm-1

Urea 1 735 A, cm 1 Me2Urea 1 710 A, cm 1

X La 55 1 672 63 1 640 70 0.92 1

XI Ce 53 1 678 57 1 648 62 0.96 1

XII Pr 50 1 673 62 1 649 61 0.98 1

XIII Nd 60 1 679 56 1 648 62 0.91 1

XIV Sm 58 1 679 56 1 650 60 0.97 1

XV Tb 49 1 671 64 1 641 69 0.96 1

XVI Dy 51 1 679 56 1 649 61 0.97 1

XVII Er 56 1 680 55 1 650 60 0.94 1

XVIII Yb 48 1 669 66 1 650 60 0.95 1

According to the results of IR spectroscopy, the absorption bands corresponding to the valence vibrations of the carbonyl groups of both urea fragments (C=O<) are shifted to the long-wavelength region, which indicates the coordination of 2,4-Me2Gl molecules through oxygen atoms. There are also absorption bands vs+as (HOH) 3550-3300 cm-1, and a set of absorption bands of 2,4-N-dimethylgly-coluryl rings.

Table 3

Characteristic data for complexes XIX - XXVII with 2,6-dimethylglycoluryl

№ Metal CC Output % 2,6-Me2Gl ICP-MS REE/2,6-Me2Gl

0=C<, cm-1

MeUrea 1 694 A, cm-1

XIX La 45 1 679 15 0.96 1

XX Ce 43 1 682 12 0.97 1

XXI Pr 40 1 672 22 0.98 1

XXII Nd 50 1 682 12 0.96 1

XXIII Sm 44 1 668 26 0.91 1

XXIV Tb 42 1 667 27 0.90 1

XXV Dy 37 1 666 28 0.89 1

XXVI Er 50 1 662 32 0.92 1

XXVII Yb 41 1 681 13 0.94 1

In the IR spectra of the synthesized complex compounds, a shift of the absorption bands corresponding to the valence vibrations of carbonyl groups (O=C<) to the long-wavelength region was observed. The observed experimental effect indicates the coordination of rare-earth element atoms through oxygen atoms of carbonyl groups of 2,6-Me2Gl methyl-urea fragments. Broad absorption bands of vs+as (HOH) in the region of 3550-3300 cm-1 and groups of absorption bands of 2,6-Me2Gl rings were also detected in the spectra.

Table 4

Characteristic data for complexes XXVIII-XXXVI with mebikar

№ Metal CC Output % Mb ICP-MS REE/Mb

0=C<, cm-1

Me2Urea 1 703 A, cm-1

XXVIII La 40 1 673 30 0.93 1

XXIX Ce 52 1 662 41 0.97 1

XXX Pr 50 1 663 40 0.98 1

XXXI Nd 51 1 663 40 0.95 1

XXXII Sm 70 1 658 45 0.97 1

XXXIII Tb 55 1 653 50 0.96 1

XXXIV Dy 46 1 654 49 0.95 1

XXXV Er 71 1 654 49 0.97 1

XXXVI Yb 55 1 655 48 0.93 1

In the IR spectra of the synthesized XXVIII-XXXVI complexes, there is a shift of 30-50 cm-1 into the long-wavelength region of the absorption band, relative to the mebikar, corresponding to valence vibrations (C=O<). This shift indicates the coordination of mebikar molecules with rare-earth metal ions through oxygen atoms. In addition, absorption bands vs+as (HOH) of water and a set of absorption bands of Mb rings were observed.

For all the obtained complex compounds in the IR spectra, a decrease in the symmetry of the nitrate anion was detected, so the free nitrate ion, as a planar ion

(point group D3h) in the IR spectra, manifests itself in the form of characteristic vibrational frequencies: asymmetric doubly degenerate valence vibrations Ve(NO), symmetric valence vibrations Vs(NO), and two frequencies of deformation vibrations SCNO3). For coordination compounds, a decrease in the symmetry of the nitrate anion coordinated by the bidentate-chelate type to Cs and C2V is observed [26]. The detection of a set of absorption bands in the IR spectra at 1530, 1252, 1051, 832 cm1 speaks in favor of the formation of complex compounds. This circumstance testifies to the coordination of atoms of rare earth elements with nitrate ions through oxygen atoms according to the bidentate-chelate type.

Powder X-ray diffraction analysis of the synthesized complex compounds of mebikar with lanthanum, cerium, neodymium, terbium, dysprosium, erbium, and ytterbium (samples XXVIII-XXIX, XXXI, XXXIII-XXXVI, respectively), allowed the determination of their crystal structure and parameters of the elementary cells. This was achieved by comparing the diffractograms of the studied samples with the diffractograms available in the CCDC database. Complex compounds were used as comparison samples: praseodymium with mebikar, PrMb, CCDC No. 1435137; samaria with mebikar, SmMb, CCDC No. 1451436; europia with mebikar, EuMb, CCDC No. 1451437; gadolinium with mebikar, GdMb CCDC No. 1450653.

For complex compounds of mebikar with cerium and neodymium (XXIX and XXXI, respectively), there was a complete correspondence of the diffraction patterns of the powder diffraction of the tested samples with the one calculated based on the structural model of the sample comparing the complex compound of praseodymium nitrate with the mebikar CCDC No. 1435137 (Fig. 2). Table 5 shows the structural data of the studied compounds and the sample comparisons. Figure 3 shows the structure of the complex compound of mebikar with neodymium nitrate.

Table 5

Parameters of crystal lattices, synthesized complexes XXIX and XXXI and the PrMb comparison sample

Compound Comparison sample PrMb Sample NdMb (XXXI) Sample CeMb (XXIX)

Unit Cell Parameters

a, A 9.8967 9.8923 9.9028

b, A 10.3689 10.3397 10.3995

c, A 11.0018 10.9857 11.0262

a, ° 74.650 74.520 74.780

ß, ° 68.064 67.984 68.151

Y, ° 67.257 67.335 67.117

Spatial group P P P

Syngony triclinic triclinic triclinic

Based on the XRD data, it is possible to judge the identity of their crystal structures. Furthermore, based on the literature data20, it can be concluded that the synthesized compounds XXIX and XXXI are centrosymmetric binuclear complexes of neodymium and cerium cations with two mebikar molecules (connected

by the center of symmetry), bidentate nitrate anions and two water molecules. The general formula of these complexes is [M(C8H14N4O2)(H2O)2(NO3)3]2, where M represents Ce, Pr, or Nd. The decrease in the parameters of the crystal lattice is associated with a natural decrease in the radii of cations in a number of rare earth metals due to lanthanide compression.

Gl_5-51_0

III III I II Hill IIIIII (II IIIIII llllllllll I IIIIIIIIIIII III llllllllllllllllllllllllllllllltllll llllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll

5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 50,0

26

Fig. 2. Diffractogram of the comparison sample PrMb (black); Complex XXXI NdMb (red)

For complex compounds of mebikar with terbium and dysprosium (XXXIII and XXXIV, respectively), a complete correspondence of the diffraction patterns of the powder diffraction of the tested samples was observed with that calculated based on the structural model of the sample comparing the complex compound of gadolinium nitrate with mebikar CCDC No. 1450653.

Table 6

Parameters of crystal lattices, synthesized complexes XXXIII and XXXIV, and the GdMb comparison sample

Compound Comparison sample GdMb Sample TbMb (XXXIII) Sample DyMb (XXXIV)

Unit Cell Parameters

a, A 10.3861 10.3523 10.3236

b, A 10.8047 10.7834 10.7495

c, A 21.2707 21.2502 21.2364

ß, ° 128.413 128.324 128.256

Spatial group P21/c P21/c P21/c

Syngony monoclinic monoclinic monoclinic

From the information provided, it appears that Table 6 shows the characteristics of the elementary cells of the synthesized complexes XXXIII and XXXIV and the comparison sample. Comparative analysis of diffractograms of the comparison sample and mebikar complexes with terbium and dysprosium nitrates suggests the identity of their crystal structures. According to literature data18, it can be concluded that the synthesized compounds are centrosymmetric binuclear complexes of terbium and dysprosium cations with two mebicar molecules (connected by a center of symmetry), bidentate nitrate anions, and two water molecules. The

general formula of these complexes is [M(CsHi4N4O2)(H2O)(NO3)3]2-H2O, where M represents Gd, Tb, or Dy.

A change in the structure of complex mebikar compounds in a number of rare-earth elements, such as an increase in their symmetry, and a decrease in the parameters of the crystal lattice, may be associated with a decrease in the radius of trivalent REE cations.

Fig. 3. Structure of the synthesized complex of neodymium nitrate with mebicar

Powder X-ray diffraction was also carried out for complex compounds of lanthanum, erbium and ytterbium with mebicar, however, the diffractograms obtained did not coincide with the diffractograms of compounds already described in the literature, which indicates their different structure from the complexes already described.

Conclusions

As a result of this work, 32 new complex compounds of N-methylglycolurils (N-monomethylglycoluryl, 2,4-N-dimethylglycoluryl, 2,6-N-dimethylglycoluryl, 2,4,6,8-N-tetramethylglycoluryl) were synthesized with hydrates of nitrates of trivalent rare earth elements (lanthanum, cerium, praseodymium, neodymium, samarium, terbium, dysprosium, erbium, ytterbium). The results of IR spectroscopy indicate that the methylglycolurils in these complexes can act as bidentate, chelating, and bridging ligands, coordinating through carbonyl groups of urea fragments. The crystal structures were proved, and the parameters of the elementary cells of complex compounds of mebikar with cerium, neodymium, terbium, and dysprosium were determined. The ratio of metal and ligand in the complexes is ~1:1, respectively. It is established that the obtained complexes are unstable in solution and disintegrate into initial substances.

The study was carried out with the support of the Tomsk State University Development Program (Priority-2030).

References

1. Gosudarstvennyi reestr lekarstvennykh sredstv [state Register of medicines of Russia].

Accessed May 5, 2023. https://grls.rosminzdrav.ru/Grls_View_v2.aspx?routingGuid=513 de8bf-aaad-4ad6-87bd-7fc7258531e1&t

2. Jacobs W., Foster D., Sansur S., Lees R. Durable glossy, matte and wrinkle finish powder

coatings crosslinked with tetramethoxymethyl glycoluril. Prog Org Coat. 1996;29(1):127-138. doi:10.1016/S0300-9440(96)00643-1

3. Heraeus Epurio Crosslinkers. UltraPureElectronicChemicals. Accessed May 5, 2023.

https://www.heraeus.com/en/hep/products_hep/ultra_pure_chemicals/crosslinkers/cross-linkers.html

4. Moore RG. Environmentally preferred antimicrobial compositions. Published online July

11, 2017. Accessed May 5, 2023. https://patents.google.com/patent/US9701931B2/en

5. Beilfuss WD, Krull ID, Gradtke RD, Steinhauer K. Use of formaldehyde andformaldehyde-

releasing compounds in a composition for controlling mycobacteria. Published online July 12, 2006. Accessed May 5, 2023. https://patents.google.com/patent/EP1679360A1/de?oq= EP1679360A1

6. Beilfuss W, Krull I, Gradtke R, Steinhauer K. Use of formaldehyde and formaldehyde-re-

leasing compounds in a composition for controlling mycobacteria. Published online June 29, 2006. Accessed May 5, 2023. https://patents.google.com/patent/US20060142291A1/ en?oq=6.Pat.+DE102004059041A1+

7. Cui K, Xu G, Xu Z, et al. Synthesis and Characterization of a Thermally and Hydrolytically

Stable Energetic Material based on N-Nitrourea. Propellants Explos Pyrotech. 2014; 39(5):662-669. doi:10.1002/prep.201300100

8. Zharkov M, Kuchurov I, Fomenkov I, Zlotin S, Tartakovsky V. Nitration of glycoluril

derivatives in liquid carbon dioxide. Mendeleev Commun. 2015; 1(25):15-16. doi:10.1016/j.mencom.2015.01.004

9. Salkeyeva L, Shibayeva A, Bakibaev A, et al. Synthesis of some multifunctional derivatives

glycoluril which are convenient synthons for the preparative production of new azohetero-cycles. Chem Bull Kazakh Natl Univ. 2013; 70(2):86-90. doi:10.15328/chemb_2013_286-90

10. Karimov U. Klinika i terapiya trevozhno-fobicheskikh nevroticheskikh rasstroistv u bol'nykh shizofreniei s yavleniyami gospitalizma. [Clinic and therapy of anxiety-phobic neurotic disorders in patients with schizophrenia with hospitalization phenomena]. Sotsialnaya Klin Psikhiatriya. 2007; 17(4):9-16.

11. Mannanov AM, Shakhabiddinov TT, Khaitov KN. Adaptol v kompleksnoi terapii psoriaza u detei. [Adaptol in the complex therapy of psoriasis in children]. Pediatr ZhurnalIm G N Speranskogo. 2010; 89(6):127-130.

12. Mkrtchyan V, Orlov V, Kozhokova L. Vozmozhnosti primeneniya adaptola v klinicheskoi praktike. [Possibilities of using adaptol in clinical practice]. Kardiologiya Serdechno-Sosud Khirurgiya. 2012; 5(6):27-32.

13. Shilina N, Statsenko M, Sporova O, Lempert B. Efficacy of Adaptol and the possibility of its differential use in patients with anxiety disorders after myocardial infarction. Ter Arkh. 2013; 85(9):29-34.

14. Tsivadze A, Ivanova I, Kireeva I. Koordinatsionnye soedineniya SoII , NiII , CuII s 2,4,6,8-tetrametil-2,4,6,8-tetraazobitsiklo[3,3,0]oktandionom-3,7 (Mebikarom). [Coordination compounds with II, NiII, CuII with 2,4,6,8-tetramethyl-2,4,6,8-tetraazobicyclo[3,3,0]oc-tanedione-3,7 (Mebicar)]. Zhurnal Neorganicheskoi Khimii. 1986; 31(7):1780-1788.

15. Tsivadze A, Ivanova I, Kireeva I. Kolebatel'nye spektry i stroenie koordinatsionnykh soedi-nenii Sd Zn Ca CuII s 2,4,6,8-tetrametil-2,4,6,8-tetraazobitsiklo[3,3,0]oktandionom-3,7. [Vibrational spectra and structure of Cd Zn Ca CuII coordination compounds with 2,4,6,8-tetramethyl-2,4,6,8-tetraazobicyclo[3,3,0]octanedione-3,7]. Zhurnal Neorganicheskoi Khimii. 1987;32(8):1876-1887.

16. Netreba E, Shabanova S, Velikozhona A, Somov N. New Binuclear Complex of Bis(2,4,6,8-Tetramethyl-2,4,6,8- Tetraazabicyclo(3.3.0)octane-3,7-Dione-0,0')-Diaqua-Tetrakis(nitrato-O,O')-Dimanganese(II) Monohydrate: Synthesis and Crystal Structure. Russ JInorg Chem. 2016;61:1414-1418. doi:10.1134/S0036023616110140

17. Netreba E, Sarnit E, Shabanov S, Velikozhon A, Somov N. New binuclear bis(2,4,6,8-tet-ramethyl-2,4,6,8-tetraazobicyclo(3.3.0)octane-3,7-dione-0,0')-tetraaqua-hexakis(nitrato-O,O')-disamarium(III) complex: Synthesis and crystal structure. Russ J Inorg Chem. 2017;62:654-658. doi:10.1134/S0036023617050175

18. Netreba E, Somov N. Crystal structure of a new binuclear complex of bis(2,4,6,8-tetrame-thyl-2,4,6,8-tetraazabicyclo(3.3.0)octane -3,7-dione-O, O')-diaqua-hexakis(nitrato-O,O')-digadolinium(III) monohydrate. J Struct Chem. 2017;58:838-842. doi:10.1134/ S0022476617040321

19. Netreba E, Sarnit EA, Shabanov SV, Velikozhon AA, Somov N. Kristallicheskaya struktura novogo biyadernogo kompleksa bis(2,4,6,8-tetrametil-2,4,6,8-tetraazabitsiklo[3.3.0]oktan-3,7-dion-o,o')-tetraakva-geksakis(nitrato-o,o')-dievropiya(III). [Crystal structure of a new binuclear complex bis (2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane -3,7-di-one-O, O')-diaqua-hexakis(nitrato-O,O')-dieuropium (III)]. J Struct Chem. 2016;57:792-797. doi:10.15372/JSC20160418

20. Netreba E, Shabanov S, Velikozhon A, Somov N. The novel dinuclear complex tetraaqua-hexakis(nitrato-0,0')bis(2,4,6,8-tetramethyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-di-one-O,O')dipraseodymium(III): Synthesis and crystal structure. Russ J Coord Chem. 2016;42:367-371. doi:10.1134/S1070328416060051

21. Bubnova V, Bodrova V, Dyachkova E, Drozdov B, Vasilyev V. Polimerizatsii izoprena s katalizatorami na osnove 2-etilgeksilfosfata neodima. [Polymerization of isoprene with catalysts based on 2-ethylhexyl phosphate of neodymium]. Kauchuk Rezina. 2014;(1). Accessed May 5, 2023. https://www.elibrary.ru/item.asp?id=21427506

22. Batyreva V, Kozik V, Serebrennikov V, Yakunina G, eds. Sintezy Soedinenii Redko-zemel 'nykh Elementov. Chast' 1. [Synthesis of Compounds ofRare Earth Elements. Part 1 ]. Izdatel'stvo Tomskogo universiteta; 1983. http://vital.lib.tsu.ru/vital/access/manager/Re-pository/vtls:000083781

23. Panshina S, Kushcherbaeva V. Issledovanie i identifikatsiya metilproizvodnykh glikolurilov {1}H i {13}S YaMR-spektroskopiei. [Investigation and identification of methyl derivatives of glycolurils by 1H and 13C NMR spectroscopy]. Chemistry and chemical technology in the 21st century: materials of the XIX International Scientific and Practical Conference of Students and Young Scientists named after Professor L.P. Kulev. 2018. P. 218219. Accessed May 5, 2023. http://earchive.tpu.ru/handle/11683/49690

24. Panshina S, Bakibaev A, Ponomarenko O, Malkov V, Kotelnikov O, Tashenov AK. Study of glycoluril and its derivatives by 1H and 13C NMR spectroscopy. Bulletin of the Karaganda University. Chemistry Series 2020. Vol. 3. P. 21-37. doi:10.31489/2020Ch3/21-37

25. Panshina S, Ponomarenko O, Bakibaev A, Malkov V. New Synthesis of 2,4,6,8-Tetrame-thyl-2,4,6,8-tetraazabicyclo[3.3.0]octane-3,7-dione Using Etidronic Acid as a "Green" Catalyst. Russ J Org Chem. 2020;56:2067-2073. doi:10.1134/S1070428020120039

26. Nakamoto K. Infrared and Raman Spectra of Inorganic and Coordination Compounds. 4th ed. Wiley; 1986.

Information about the authors:

Guslyakov Alexey N. - Postgraduate Student of the first year of study, Junior Researcher,

Center for Research in the Field of Materials and Technologies, Chemical Faculty, Tomsk State

University (Tomsk, Russia). E-mail: guslyakov.aleksej@bk.ru

Razgulyaeva Yulia D. - Master Degree, Junior Researcher, Laboratory for Comprehensive

Analysis of Big Bioimage Data, Chemical Faculty, Tomsk State University (Tomsk, Russia).

E-mail: yuliya-razgulyaeva@rambler.ru

Turebaeva Pana D. - 3rd year Doctoral Student of the L.N. Gumilyov Eurasian National University (Astana, Kazakhstan). E-mail: pana90@mail.ru

Bakibaev Abdigali A. - Doctor of Chemistry, Professor of the Department of Organic Chemistry, Leading Researcher Laboratory of Organic Synthesis, Chemical Faculty, Tomsk State University (Tomsk, Russia). E-mail: E-mail: bakibaev@mail.ru

Yerkasov Rakhmetiilla Sh. - Doctor of Chemistry, Professor of the Department of Chemistry of the L.N. Gumilyov Eurasian National University (Astana, Kazakhstan). E-mail: erkass@mail.ru

Contribution of the authors: the authors contributed equally to this article. The authors declare no conflicts of interests.

Сведения об авторах:

Гусляков Алексей Николаевич - аспирант, младший научный сотрудник Центра исследований в области материалов и технологий химического факультета Томского государственного университета (Томск, Россия). E-mail: guslykov.aleksej@bk.ru Разгуляева Юлия Дмитриевна - младший научный сотрудник лаборатории комплексного анализа больших данных биоизображений химического факультета Томского государственного университета (Томск, Россия). E-mail: yuliya-razgulyaeva@rambler.ru Туребаева Пана Даулетовна - докторант Евразийского национального университета им. Л.Н. Гумилева (Астана, Казахстан). E-mail: pana90@mail.ru

Бакибаев Абдигали Абдиманапович - доктор химических наук, профессор кафедры органической химии, ведущий научный сотрудник лаборатории органического синтеза химического факультета Томского государственного университета (ул. Ленина, 36, Томск, Россия, 634050). E-mail: bakibaev@mail.ru

Еркасов Рахметулла Шарапиденович - доктор химических наук, профессор кафедры химии Евразийского национального университета. Л.Н. Гумилева (ул. Сатпаева, 2, г. Астана, Казахстан, 010000). E-mail: erkass@mail.ru

Вклад авторов: все авторы сделали эквивалентный вклад в подготовку публикации. Авторы заявляют об отсутствии конфликта интересов.

The article was submitted 27.07.2023; accepted for publication 15.12.2023 Статья поступила в редакцию 27.07.2023; принята к публикации 15.12.2023