Synthesis and structure of bismuth complexes [p-Tol 4e] + 3[Bi 3i 1 2] 3-∙hoch 2CH 2oC 2H 5 e=p, Sb Текст научной статьи по специальности «Химические науки»

DOI: 10.14529/chem150406

SYNTHESIS AND STRUCTURE OF BISMUTH COMPLEXES [p-Tol4E]+3[Bi3li2]3"HOCH2CH2OC2H5 E=P, Sb

V.V. Sharutin, [email protected] O.K. Sharutina, [email protected] V.S. Senchurin, [email protected] R.M. Khisamov, [email protected] T.V. Mosunova, wik [email protected]

South Ural State University, Chelyabinsk, Russian Federation

The interaction of equimolar amounts of tetra-p-tolylphosphonium and tetra-p-tolylstybonium iodides with bismuth triiodide in 2-ethoxyethanol leads to formation of the complexes [p-Tol4E]+3[Bi3I12]3- • HOCH2CH2OC2H5 E=P (I), Sb (II). X-ray diffraction analysis of compounds (I) and (II) has shown that in the cations of complexes I and II the coordination of phosphorus and antimony atoms is tetrahedral (angles equal: CPC 107.3(3)°-113.4(4)° (I), CSbC 105.4(3)°-113.7(3)° (II); bond lengths for P-C and Sb-C are 1.761(9)-1.815(7) A and 2.085(8)-2.099(8) A, respectively). In trinuclear anions [Bi3I12]3- the terminal fragments BiI3 (Bi-Iterm 2.8714(5)-2.9181(5) A (I), 2.8867(5)-2.9248(6) A (II)) are bonded to the central bismuth atom through six ^-bridging iodine atoms (Bi-Ibr 3.0454(6)-3.3891(6) A (I), 3.0595(4)-3.3694(6) A (II)).

Keywords: bismuth triiodide, bismuth complexes [p-Tol4E]+3[Bi3I12]3 HOCH2CH2OC2H5, E=P, Sb, synthesis, structure.

Introduction

Ionic bismuth complexes with linear anions [Bi3I12]3-, in which the bismuth atoms are bonded through six ^-bridging iodine atoms, are described in the literature as separate examples, where nitrogen-containing acyclic or heterocyclic cations stand as counter-ions [1-3]. Thus far only one similar complex with phosphonium cation is known [4]; like complexes with organoantimony cations are not known.

In the present paper we have synthesized two new phosphorus- and antimony-containing bismuth complexes [p-Tol4E]+3[Bi3I12]3-HOCH2CH2OC2H5 (E=P, Sb) with the linear anion [Bi3I12]3 and carried out X-ray diffraction analysis of these.

Experimental

tris(Tetra-p-tolylphosphonium) hexakis(^2-iodo)-hexaiodo-tribismuth 2-ethoxyethanol solvate (I). The solution of 0.100 g (0.19 mmol) tetra-p-tolylphosphonium and 0.113 g (0.19 mmol) bismuth triiodide in 15 mL 2-ethoxyethanol was obtained. The solvent was slowly evaporated. The yield was 0.142 g (65%) of orange-red crystals of complex I with decomposition temperature 195 °C. Found, %: C 30.83, H 2.74. For C88H9402P3Bi3I12 calculated,0/«: C 30.54, H 2.85.

tris(Tetra-p-tolylstibonium) hexakis(^2-iodo)-hexaiodo-tribismuth 2-ethoxyethanol solvate (II). It was obtained by the similar procedure. Orange-red crystals of complex II were isolated (48%) with decomposition temperature 219 °C. Found, %: C 28.56, H 2.54. For C88H9402Sb3Bi3I12 calculated, %: C 28.43, H 2.62.

The X-ray diffraction analyses of crystals I and II were performed on the Bruker D8 QUEST automatic four-circle diffractometer (Mo Ka-emission, X = 0.71073 A, graphite monochromator). The data were collected and analyzed, the unit cell parameters were refined, and the absorption correction was applied using the SMART and SAINT-Plus programs [5]. All calculations for structure determination and refinement were performed using the SHELXL/PC [6] and OLEX2 programs [7]. The structures were determined by the direct method and refined by the least-squares method in the anisotropic approximation for non-hydrogen atoms. The main crystallographic data and refinement results for the structure are listed in Table 1, the selected bond lengths and bond angles are given in Table 2.

The full tables of atomic coordinates, bond lengths, and bond angles were deposited with the Cambridge Crystallographic Data Centre (CCDC 1053856, 1049481; [email protected]; http: //www .ccdc.cam.ac.uk).

Table 1

Crystallographic data and the experimental and structure refinement parameters for compounds I, II

Parameter Value

I II

Empirical formula C88H94O2P3I12Bi3 C88H94O2Sb3l12BÎ3

Formula weight 3426.28 3698.62

T, K 296(2) 296(2)

Crystal system Triclinic Triclinic

Space group PT P1

a, A 12.4517(6) 12.4055(4)

b, A 18.0680(9) 18.3805(5)

c, A 24.1711(10) 24.6523(7)

a, deg 87.532(2) 87.401(2)

P, deg 87.039(2) 87.049(2)

Y, deg 75.281(2) 74.124(2)

V, A3 5250.0(4) 5396.8(3)

Z 4 2

p(calcd.), g/cm3 2.167 2.276

mm"1 8.630 9.085

F(000) 3136.0 3352.0

Crystal size, mm 0.26x0.25x0.16 0.33x0.3x0.14

29 Range of data collection, deg 4.04 - 46.56 4.1 - 53.54

Range of refraction indices -13 < h < 13 -20 < k < 20 -26 < l < 26 -15 < h < 15 -23 < k < 23 -31 < l < 31

Measured reflections 94609 102068

Independent reflections 15056 22967

Rint 0.0486 0.0587

Refinement variables 990 990

GOOF 1.036 1.007

R factors for F2 > 2c(F2) Rj= 0.0361 wR2= 0.0817 Rj = 0.0382 wR2 = 0.0705

R factors for all reflections Rj= 0.0579 wR2 = 0.0941 Rj = 0.0711 wR2 = 0.0811

Residual electron density (min/max), e/A3 1.42/-0.77 1.29/-0.92

Table 2

Selected bond lengths and bond angles in the structure of compounds 1, 2

Bond d, Â Angle ю, deg

I

P(1) - С(1) 1.788(8) C(1)P(1)C(11) 109.0(4)

P(1) - С(11) 1.800(7) C(1)P(1)C(21) 110.0(4)

P(1) - С(21) 1.761(9) C(1)P(1)C(31) 109.6(4)

P(1) - С(31) 1.799(8) C(11)P(1)C(21) 110.3(4)

P(2) - С(41) 1.804(7) C(11)P(1)C(31) 109.9(3)

P(2) - С(51) 1.791(6) C(21)P(1)C(31) 108.0(4)

Table (continued)

Bond d, Ä Angle ra, deg

I

P(2) - C(61) 1.770(7) C(41)P(2)C(51) 107.5(3)

P(2) - C(71) 1.795(7) C(41)P(2)C(61) 109.6(3)

P(3) - C(81) 1.800(7) C(41)P(2)C(71) 111.7(3)

P(3) - C(91) 1.791(7) C(51)P(2)C(61) 109.3(3)

P(3) - C(101) 1.815(7) C(51)P(2)C(71) 111.4(3)

P(3) - C(111) 1.800(8) C(61)P(2)C(71) 107.3(3)

Bi(i) - I (1) 3.0748(5) C(81)P(3)C(91) 109.7(3)

Bi(1) - I (2) 3.0706(5) C(81)P(3)C(101) 109.1(3)

Bi(1) - I (3) 3.0444(4) C(81)P(3)C(111) 107.7(4)

Bi(2) - I (1) 3.3046(5) C(91)P(3)C(101) 107.8(3)

Bi(2) - I (2) 3.2715(5) C(91)P(3)C(111) 109.1(3)

Bi(2) - I (3) 3.3556(5) C(101)P(3)C(111) 113.4(4)

Bi(2) - I (4) 2.9181(5) I(1)Bi(1)I(2) 91.611(13)

Bi(2) - I (5) 2.8714(5) I(7)Bi(3)I(9) 88.583(16)

Bi(2) - I (6) 2.9049(5) I(7)Bi(3)I(8) 85.096(15)

Bi(3) - I (7) 3.0669(5) I(8)Bi(3)I(9) 88.406(15)

Bi(3) - I (8) 3.0654(5) I(2)Bi(2)I(3) 79.092(13)

Bi(3) - I (9) 3.0454(6) I(2)Bi(2)I(4) 88.012(16)

Bi(4) - I (7) 3.3153(6) I(2)Bi(2)I(5) 93.250(16)

Bi(4) - I (8) 3.3891(6) I(2)Bi(2)I(6) 169.597(15)

Bi(4) - I (9) 3.2907(7) I(3)Bi(2)I(4) 94.399(15)

Bi(4) - I (10) 2.8958(6) I(3)Bi(2)I(5) 165.035(15)

Bi(4) - I (11) 2.9040(7) I(3)Bi(2)I(6) 92.370(15)

Bi(4) - I (12) 2.9088(7) I(4)Bi(2)I(5) 98.194(16)

I(4)Bi(2)I(6) 98.652(17)

I(5)Bi(2)I(6) 93.689(17)

I(7)Bi(4)I(8) 76.406(14)

I(7)Bi(4)I(9) 80.500(15)

I(7)Bi(4)I( 10) 87.219(17)

I(7)Bi(4)I(11) 93.121(18)

I(7)Bi(4)I( 12) 170.78(2)

I(8)Bi(4)I(9) 79.245(15)

I(8)Bi(4)I(10) 163.130(16)

I(8)Bi(4)I(11) 87.587(17)

I(8)Bi(4)I(12) 101.94(2)

I(9)Bi(4)I(10) 94.251(17)

I(9)Bi(4)I(11) 166.381(18)

I(9)Bi(4)I( 12) 90.28(2)

I(10)Bi(4)I(11) 97.464(19)

I( 10)Bi(4)I( 12) 93.58(2)

I(11)Bi(4)I(12) 95.88(2)

II

Sb(1) - C(1) 2.089(6) C(1)Sb(1)C(11) 107.6(3)

Sb(1) - C(11) 2.099(8) C(1)Sb(1)C(21) 110.8(3)

Sb(1) - C(21) 2.091(7) C(1)Sb(1)C(31) 108.8(3)

Table (end)

Bond d, Â Angle ю, deg

II

Sb(1) - С(31) 2.085(8) C(11)Sb(1)C(21) 112.0(3)

Sb(2) - С(41) 2.086(7) C(11)Sb(1)C(31) 110.9(3)

Sb(2) - С(51) 2.097(7) C(21)Sb(1)C(31) 106.9(3)

Sb(2) - С(61) 2.097(7) C(41)Sb(2)C(51) 109.7(3)

Sb(2) - С(71) 2.086(7) C(41)Sb(2)C(61) 106.1(3)

Sb(3) - С(81) 2.092(8) C(41)Sb(2)C(71) 113.6(3)

Sb(3) - С(91) 2.073(9) C(51)Sb(2)C(61) 110.2(3)

Sb(3) - С(101) 2.090(9) C(51)Sb(2)C(71) 105.6(3)

Sb(3) - С(111) 2.085(8) C(61)Sb(2)C(71) 111.7(3)

Bi(i) - I (1) 3.0785(5) C(81)Sb(3)C(91) 113.7(3)

Bi(1) - I (2) 3.0866(5) C(81)Sb(3)C(101) 113.1(3)

Bi(1) - I (3) 3.0595(4) C(81)Sb(3)C(111) 105.4(3)

Bi(2) - I (2) 3.3341(5) C(91)Sb(3)C(101) 107.9(3)

Bi(2) - I (3) 3.3376(5) C(91)Sb(3)C(111) 109.6(3)

Bi(2) - I (4) 2.9191(5) C(101)Sb(3)C(111) 106.8(4)

Bi(2) - I (5) 2.9234(6) I(1)Bi(1)I(2) 92.813(14)

Bi(2) - I (6) 2.8867(5) I(1)Bi(1)I(3) 93.202(13)

Bi(3) - I (7) 3.0754(5) I(2)Bi(2)I(3) 78.388(13)

Bi(3) - I (8) 3.0672(5) I(2)Bi(2)I(4) 92.235(15)

Bi(3) - I (9) 3.0750(6) I(2)Bi(2)I(5) 167.390(16)

Bi(4) - I (8) 3.3694(6) I(2)Bi(2)I(6) 89.205(16)

Bi(4) - I (9) 3.2947(6) I(3)Bi(2)I(4) 91.055(14)

Bi(4) - I (10) 2.9086(8) I(3)Bi(2)I(5) 93.163(15)

Bi(4) - I (11) 2.9248(6) I(3)Bi(2)I(6) 166.958(16)

Bi(4) - I (12) 2.9032(6) I(4)Bi(2)I(5) 97.312(17)

I(4)Bi(2)I(6) 93.459(17)

I(5)Bi(2)I(6) 98.383(17)

I(7)Bi(3)I(8) 94.620(15)

I(7)Bi(3)I(9) 91.955(16)

I(8)Bi(3)I(9) 88.963(16)

I(8)Bi(4)I(9) 80.444(15)

I(8)Bi(4)I(10) 101.90(2)

I(8)Bi(4)I( 11) 86.408(17)

I(8)Bi(4)I(12) 163.561(19)

I(9)Bi(4)I(10) 89.58(2)

I(9)Bi(4)I( 11) 166.666(19)

I(9)Bi(4)I(12) 94.318(16)

I(10)Bi(4)I(11) 95.33(2)

I( 10)Bi(4)I( 12) 93.58(2)

I(11)Bi(4)I(12) 97.730(19)

Results and Discussion

It has been shown that the interaction of equimolar amounts of tetra-p-tolylphosphonium and tetra-p-tolylstybonium iodides with bismuth triiodide in 2-ethoxyetanol leads to formation of the ionic bismuth complexes with the anion [Bi3I12]3-, which contain the solvate molecule of the solvent:

HOCH2CH2OEt

3 ^-ToUEI + 3 Bil3 ^ [p-Tol4E]+3[Bi3li2]3^HOCH2CH2OEt

E = P (I); Sb (II).

According to X-ray diffraction data, the phosphorus and antimony atoms of the cations have weakly distorted tetrahedral coordination (Fig. 1 and 2). Angles CPC and CSbC equal 107.3(3)°-113.4(4)° and 105.4(3)°-113.7(3)°, respectively. Bond lengths P-C (1.761(9)-1.815(7) A) and Sb-C (2.085(8)-2.099(8) A) are near to the sums of covalent radii of phosphorus, carbon (1.88 A) and antimony, carbon (2.19 A) [8]. In trinuclear centrosymmetrical anions [Bi3I12]3- the terminal fragments BiI3 (Bi Iterm 2.8714(5)-2.9181(5) A (I), 2.8867(5)-2.9248(6) A (II)) are bonded to the central bismuth atom through six ^-bridging iodine atoms (Bi-Ibr 3.0454(6)-3.3891(6) A (I), 3.0595(4)-3.3694(6) A (II)). The terminal fragments BiI3 are in the masked conformation.

Fig. 1. The structure of complex I

C{7)

C{123) C{107)

C{104)

C{103) 3(102)

1(11)

l{10)

Fig. 2. The structure of complex II

The structural organization in crystals I and II results from weak interactions of the type H—I and H-O. In I the bridging ^2-atoms of iodine in anions are bonded (2.86-3.16 A) to the hydrogen atoms of phosphonium cations, in II the similar bonds are formed with participation of both bridging (3.10 A) and terminal (3.15 A) atoms of iodine (which is somewhat less than the sum of Van der Waals radii of hydrogen and iodine, namely, 3.3 A [8]). No significant close contacts of the ions with the solvent molecules have been observed, but the molecules of 2-ethoxyethanol are bonded with each other by hydrogen bonds H-0 (2.33 A (I) and 2.62 A (II)) (Fig. 3).

I II

Fig. 3. Association of solvent molecules in crystals I and II

Conclusions

Complexes [p-Tol4E]+3[Bi3Ii2]3_ • HOCH2CH2OC2H5 E=P (I), Sb (II) have been synthesized by interaction of equimolar amounts of tetra-p-tolylphosphonium and tetra-p-tolylstibonium iodides with bismuth triiodide in 2-ethoxyethanol. The structure of the products has been established by X-ray diffraction analysis.

References

1. Geiser U., Wade E., Wang H.H., Williams J.M. Structure of a New Iodobismuthate: Tetra(n-butyl)ammonium 1,2;1,2;1,2;2,3;2,3;2,3-hexa-^-iodo-1,1,1,3,3,3-hexaiodotribismuthate (III) (3:1) Acta Crystallographica Section C, 1990, vol. 46, no 8, pp. 1547-1549. DOI: 10.1107/S0108270190003006

2. Carmalt C.J., Farrugia L.J., Norman N.C. Structural Studies on some Iodoantimonate and Iodobismuthate Anions Zeitschrift für anorganische und allgemeine Chemie, 1995, vol. 621, no. 47, pp. 4756. DOI: 10.1002/zaac.19956210110

3. Mallick D., Sarker K.K., Saha R., Mondal T.K., Sinha C. Intercalated Iodobismuthate in the Layers of Azoimidazoles. Structure, Photochromism and DFT Computation Polyhedron, 2013, vol. 54, pp. 147-157. DOI: 10.1016/j.poly.2013.01.061

4. Sharutin V.V., Egorova I.V., Klepikov N.N., Boyarkina E.A., Sharutina O.K. Synthesis and Structure of Bismuth Complexes [Ph3MeP]6+ [Bi^B^]3- [Bi^B^]3- • H2O2, [Ph3EtP]3+ [Bi2y3-, [Ph3MeP]3+ [Bi3I12]3-, [Ph3(iso-Pr)P]3+ [Bi3I12]3- • 2Me2C=O, and [Ph4Bi]3+ [Bi5I18]3- Russian Journal of Inorganic Chemistry, 2009, vol. 54, no. 1, pp. 52-68. DOI: 10.1134/S0036023609010124

5. Bruker (1998). SMART and SAINT-Plus. Versions 5.0. Data Collection and Processing Software for the SMART System. Bruker AXS Inc., Madison, Wisconsin, USA.

6. Bruker (1998). SHELXTL/PC. Versions 5.10. An Integrated System for Solving, Refining and Displaying Crystal Structures From Diffraction Data. Bruker AXS Inc., Madison, Wisconsin, USA.

7. Dolomanov O.V., Bourhis L.J., Gildea R.J., Howard J.A.K., Puschmann H. OLEX2: a Complete Structure Solution, Refinement and Analysis Program. J. Appl. Cryst., 2009, vol. 42, pp. 339-341.

8. Batsanov S.S. Atomnye Radiusy Jelementov. Zhurn. neorgan. himii. [Russian Journal of Inorganic Chemistry], 1991, vol. 36, no. 12, pp. 3015-3037.

Received 18 September 2015

УДК 547.53.024+549.242+548.312.5 DOI: 10.14529/chem150406

СИНТЕЗ И СТРОЕНИЕ КОМПЛЕКСОВ ВИСМУТА [p-Tol4E]+3[Bi3l12]3~HOCH2CH2OC2H5 E=P, Sb

В.В. Шарутин, О.К. Шарутина, В.С. Сенчурин, Р.М. Хисамов, Т.В. Мосунова

Южно-Уральский государственный университет, г. Челябинск

Взаимодействием эквимолярных количеств иодидов тетра-п-толилфосфония и тетра-п-толилстибония с трииодидом висмута в 2-этоксиэтаноле получены комплексы [p-Tol4E]+3 [Bi3I12]3^HOCH2CH2OC2H5 E=P (I), Sb (II). Проведен рентгеноструктурный анализ I и II. В катионах координация атомов фосфора и сурьмы тетраэдрическая (углы CPC 107.3(3)°-113.4(4)° (I), CSbC 105.4(3)°-113.7(3)° (II); связи P-C 1.761(9)-1.815(7) Ä (I), Sb-C 2.085(8)-2.099(8) Ä (II). В трехъядерных анионах [Bi3I12]3- концевые фрагменты BiI3 (Bi-Iтерм 2.8714(5)-2.9181(5) Ä (I) 2.8867(5)-2.9248(6) Ä (II)) связаны с центральным атомом висмута посредством шести д2-мостиковых атомов иода (В^!мост 3.0454(6)-3.3891 (6) Ä (I) 3.0595(4)-3.3694(6) Ä (II)).

Ключевые слова: трииодид висмута, комплексы висмута 'p-Tol4E]+3[Bi3I12_]3~ HOCH2CH2OC2H5, E=P, Sb, синтез, строение.

Литература

1. Structure of a New Iodobismuthate: Tetra(n-butyl)ammonium 1,2;1,2;1,2;2,3;2,3;2,3-hexa-^-iodo-1,1,1,3,3,3-hexaiodotribismuthate (III) (3:1) / U. Geiser, E. Wade, H.H. Wang, J.M. Williams // Acta Crystallographica Section C, 1990. - V. 46, № 8. - P. 1547-1549.

2. Carmalt, C.J. Structural Studies on some Iodoantimonate and Iodobismuthate Anions / C.J. Car-malt, L.J. Farrugia, N.C. Norman // Zeitschrift für anorganische und allgemeine Chemie. - 1995. -V. 621, №. 47. - Р. 47-56.

3. Intercalated Iodobismuthate in the Layers of Azoimidazoles. Structure, Photochromism and DFT Computation / D. Mallick, K.K. Sarker, R. Saha, T.K. Mondal et al. // Polyhedron. - 2013. - V. 54, P.147-157.

4. Synthesis and Structure of Bismuth Complexes [Ph3MeP]6+ [Bi^B^]3- [Bi^B^]3- • H2O2, [Ph3EtP]3+ [Bi2LJ3-, [Ph3MeP]3+ [Bi3I12]3-, [Ph3(iso-Pr)Pb+ [Bi3I12]3- • 2Me2C=O, and [Ph4Bib+ ^I^]3-/ V.V. Sharutin, I.V. Egorova, N.N. Klepikov, E.A. Boyarkina et al // Russian Journal of Inorganic Chemistry. - 2009. - V. 54, № 1. - P. 52-68.

5. Bruker (1998). SMART and SAINT-Plus. Versions 5.0. Data Collection and Processing Software for the SMART System. Bruker AXS Inc., Madison, Wisconsin, USA.

6. Bruker (1998). SHELXTL/PC. Versions 5.10. An Integrated System for Solving, Refining and Displaying Crystal Structures From Diffraction Data. Bruker AXS Inc., Madison, Wisconsin, USA.

7. OLEX2: a Complete Structure Solution, Refinement and Analysis Program / O.V. Dolomanov, L.J. Bourhis, R.J. Gildea et al. // J. Appl. Cryst. - 2009. - V. 42. - P. 339-341.

8. Бацанов, С.С. Атомные радиусы элементов / С.С. Бацанов // Журн. неорган. химии. - 1991. - Т. 36. - № 12. - С. 3015-3037.

Шарутин Владимир Викторович - доктор химических наук, профессор, старший научный сотрудник УНИД, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: [email protected]

Шарутина Ольга Константиновна - доктор химических наук, профессор, кафедра аналитической химии, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: [email protected]

Сенчурин Владислав Станиславович - кандидат химических наук, доцент, кафедра органической химии, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: [email protected]

Хисамов Радмир Мухаметович - студент химического факультета, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: [email protected]

Мосунова Татьяна Владимировна - кандидат химических наук, доцент, кафедра экологии и природопользования, химический факультет, Южно-Уральский государственный университет. 454080, г. Челябинск, пр. им. В.И. Ленина, 76. E-mail: [email protected]

Поступила в редакцию 18 сентября 2015 г.

ОБРАЗЕЦ ЦИТИРОВАНИЯ

Synthesis and structure of bismuth complexes [p-Tol4E]+3[Bi3I12]3-^HOCH2CH2OC2H5 E=P, Sb / V.V. Sharutin, O.K. Sharutina, V.S. Senchurin et al. // Вестник ЮУрГУ. Серия «Химия». - 2015. - Т. 7, № 4. - С. 44-51. DOI: 10.14529/chem150406

FOR CITATION

Sharutin V.V., Sharutina O.K., Senchurin V.S., Khisamov R.M., Mosunova T.V. Synthesis and Structure of Bismuth Complexes [p-Tol4E]+3[Bi3I12]3-^HOCH2CH2OC2H5 E=P, Sb. Bulletin of the South Ural State University. Ser. Chemistry. 2015, vol. 7, no. 4, pp. 44-51. DOI: 10.14529/chem150406