DFT study of molecular structure of 5,10,15,20-tetrakis(4¢-halogenophenyl)porphyrins and their isomers Текст научной статьи по специальности «Химические науки»

УДК: 544.122

DFT ИЗУЧЕНИЕ МОЛЕКУЛЯРНОЙ СТРУКТУРЫ 5,10,15,20-ТЕТРАКИС(4'-ГАЛОГЕНФЕНИЛ)ПОРФИНОВ И ИХ ИЗОМЕРОВ

И.Ю. Курочкин, А.Е. Погонин, А.А. Отлетов, А.Н. Киселев, Г.В. Гиричев

Иван Юрьевич Курочкин, Арсений Андреевич Отлетов, Георгий Васильевич Гиричев

Кафедра физики, Ивановский государственный химико-технологический университет, Шереметевский пр., 7, Иваново, Российская Федерация, 153000

E-mail: [email protected], [email protected], [email protected] Александр Евгеньевич Погонин*

Кафедра технологии керамики и наноматериалов, Ивановский государственный химико-технологический университет, Шереметевский пр., 7, Иваново, Российская Федерация, 153000 E-mail: [email protected]*

Алексей Николаевич Киселев

Кафедра органической химии, Ивановский государственный химико -технологический университет, Шереметевский пр., 7, Иваново, Российская Федерация, 153000 E-mail: [email protected]

Настоящая статья является продолжением работ по установлению чувствительности электронографического метода в отношении определения конформационного состава макроциклических молекул, осложненных введением групп-заместителей различной природы. С помощью квантово-химических расчетов (метод DFT, функционал B3LYP) изучено конформационное многообразие 5,10,15,20-тетракис(4'-Х)фенилпорфинов ^-4CHX-HP: X = F, Br). Рассмотренные конформеры отличаются положением -4CHXгрупп относительно макроцикла. Относительные энергии конформеров CH4F-HP были вычислены с использованием различных базисных наборов с целью подбора варианта, наиболее оптимального по соотношению «качество расчета/вычислительная стоимость». Согласно результатам расчетов наиболее энергетически выгодной структурой п-4СНХ-НР является кон-формер симметрии С2» В то же время, относительные энергии других конформеров весьма малы, поэтому их возможное присутствие в паре необходимо учитывать при обработке экспериментальных электронографических (ЭГ) данных. Замена атомов Fна атомы Br при переходе 4CH4F-HP^4CHBr-HP не приводит к значительным изменениям строения пор-фиринового остова. Выполнен анализ чувствительности метода газовой электронографии к структурным изменениям, обусловленным различным положением галогенфенильных заместителей. Сопоставлены теоретические функции радиального распределения f(r) конформеров п-4CHX-HP,а также мета- и орто-изомеров - м-4CHX-HP и о-4CHX-HP. Результаты моделирования свидетельствуют о возможности надежного экспериментального определения расстояний между химически связанными атомами, в то время как уточнение положения галогенфенильных заместителей относительно макроциклического остова молекулы находится на пределе возможностей метода. На основе экспериментальных данных можно надежно различить мета- и орто- изомеры 4CHX-HP, в особенности, в случае бромзамещенных фенильных групп.

Ключевые квантово-химические расчеты, теория функционала плотности, порфирин, конформа-ционный анализ

Для цитирования:

Курочкин И.Ю., Погонин А.Е., Отлетов А.А., Киселев А.Н., Гиричев Г.В. DFT изучение молекулярной структуры 5,10,15,20-тетракис(4'-галогенфенил)порфинов и их изомеров. Изв. вузов. Химия и хим. технология. 2020. Т. 63. Вып. 1. С. 51-57

For citation:

Kurochkin I.Yu., Pogonin A.E., Otlyotov A.A., Kiselev A.N., Girichev G.V. DFT study of molecular structure of 5,10,15,20-tetrakis(4'-halogenophenyl)porphyrins and their isomers. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. [Russ. J. Chem. & Chem. Tech.]. 2020. V. 63. N 1. P. 51-57

DFT STUDY OF MOLECULAR STRUCTURE OF 5,10,15,20-TETRAKIS(4'-HALOGENOPHENYL)PORPHYRINS AND THEIR ISOMERS

I.Yu. Kurochkin, A.E. Pogonin, A.A. Otlyotov, A.N. Kiselev, G.V. Girichev

Ivan Yu. Kurochkin, Arseniy A. Otlyotov, Georgy V. Girichev

Department of Physics, Ivanovo State University of Chemistry and Technology, Sheremetevskiy ave., 7, Ivanovo, 153000, Russia

E-mail: [email protected], [email protected], [email protected] Alexander E. Pogonin*

Department of Nanomaterials and Ceramic Technology, Ivanovo State University of Chemistry and Technology, Sheremetevskiy ave., 7, Ivanovo, 153000, Russia E-mail: [email protected]*

Aleksey N. Kiselev

Department of Organic Chemistry, Ivanovo State University of Chemistry and Technology, Sheremetevskiy ave., 7, Ivanovo, 153000, Russia E-mail: [email protected]

Conformational manifold of 5,10,15,20-tetrakis(4'-halogenophenyl)porphyrins (p-4CHX-HP; X=F, Br) was studied by DFT calculations (functional B3LYP). The conformers are different by positions of -4CHX groups relative to the macrocyclic core. Relative energies of the conformers of 4C6H4F-H2P were calculated with use of different basis sets in order to find the optimal ratio «quality./ computational cost». According to the results of the calculations, conformers of C2V symmetry are the most energetically favorable. However, relative energies of other conformers are quite low, therefore they should be taken into account at the treatment of the gas-phase electron diffraction (GED) experimental data. The sensitivity of the GED method to structural changes induced by different relative positions of halogenophenyl substituents was examined. Model radial distribution curves f(r) for conformers of p-4CHX-HP, as well as meta- and ortho- isomers (m-4CHX-HP and o-4C6H4X-H2P) were compared. The results of the model studies demonstrate that the bond distances can be reliably determined from experimental data, while the refinement of the positions of halogenophenyl substituents relative to the macrocyclic core is at the limit of the possibilities of the GED method. Meta- and ortho- isomers of 4CHX-HP can be distinguished based on the experimental data, especially in the case of bromine-substituted phenyl groups.

Key words: quantum chemical calculations, DFT, porphyrin, conformational analysis

INTRODUCTION phase electron diffraction (GED). The structures determined by GED can be used for the development of cor-

According to modern TO^p^ the under- responding subsections of stereochemistry and for the

standing of electronic and geometry structure of a mol- assessment of performance of various theoretical

ecule is the key point in interpretation and prediction methods. However, in the case of large molecules the

of chemica^ physical and biol°gical properties of a structural refinement of GED data is usually a nontri-

c°mp°und. The structural studies commonly exploit a vial procedure [1]. In particular, macroheterocyclic li-

number of theoretical (quantum-chemical) and experi- gands and their metal complexes are characterized by

mental (X-ray diffraction, gas-phase electron diffrac- a low volatility and require very high temperatures during

tion, etc.) methods. It should, however, be mentioned effusion experiments [2]. The macroheterocyclic com-

that the solid state structures determined by X-ray dif- pounds can exhibit different types of non-planar distor-

fraction are usually distorted due to intermolecular in- tions depending on the nature of central metal atom and

teractions. Gas-phase structures do not suffer from kind of substituent [3-5], and this circumstance brings

these interactions and reflect the properties of a free the additional difficulties in the structural analysis.

molecule. The most common experimental method for Therefore, only few structures of macroheterocycles

structural determination of free molecules is the gas- have been determined experimentally so far, while

most studies of the free molecules of porphyrin derivatives were limited to quantum-chemical calculations.

In the literature one can find a series of GED investigations of the structures of phthalocyanine complexes [6-12]. However, among the porphyrins, only copper and tin octamethylporphyrins [13, 14] and copper and zinc etioporphyrins-II [15, 16] were studied by GED. The sensitivity of the GED method to the determination of the conformational composition of macro-cyclic compounds bearing hydrocarbonic substutuents was examined and the refinement procedure was adjusted in [15, 16]. In the case of the metal etioporphyrins-II [15, 16] only the geometry of the macrocyclic framework, but not the relative positions of the -CH3 and -C2H5 substituents can be reliably determined.

The present contribution continues the series of studies devoted to determination of sensitivity of GED method to the determination of conformational composition of macrocycles, but deals with substitu-ents containing halogen atoms. The objects of study are 5,10,15,20-tetrakis(4'-halogenophenyl) porphyrin (P-4C6H4X-H2P; X=F, Br).

The structures and the conformational diversity were examined with use of quantum-chemical calculations. Theoretical consideration of the sensitivity of GED method to the determination of conformational and isomeric composition of the vapor was also performed. For this purpose, meta- and ortho-isomers were also calculated: 5,10,15,20-tetrakis(3' -halogenophenyl)porphyrin (m-4C6H4X-H2P; X=F, Br) and 5,10,15,20-tetrakis(2'-halogenophenyl) porphyrin (0-4C6H4X-H2P; X=F, Br).

Fig. 1. Molecular structure and atom numbering of 0-4C6H4X-

H2P, ra-4C6H4X-H2P, ,р-4СбШХ-Н2Р (X=F, Br) Рис. 1. Молекулярная структура и нумерация атомов для о-4C6H4X-H2P, .M-4C6H4X-H2P, «-4C6H4X-H2P (X=F, Br)

COMPUTATIONAL DETAILS

Structural parameters of P-4C6H4X-H2P (X = F, Br) were optimized under C2V, C2h (two variants), D2 and D2h (two variants) symmetries, under C2, D2, Ci, C2h (two variants) and C2v symmetries - for m-4C6H4X-

H2P (X = F, Br) and under D2, Ci, C2h (two variants) and C2v symmetries - for 0-4C6H4X-H2P (X = F, Br). Vibrational frequencies were calculated for all the optimized structures. All calculations were performed using DFT (B3LYP functional [17,18]). In order to examine the influence of basis set on relative energies and structural parameters, five basis sets were tested in the case of p-4C6H4F-^P:(A) 6-31G(d,p)[19]; (B) pVTZ, taken from the EMSL library [20] (denoted as «GAMESSpVTZ»); (C) cc-pVTZ [21]; (D) pcseg-2 [22]. Basis set (B) was chosen for the calculations of 4C6H4Br-H2P. Core electrons of Br atom were described by pseudopotential ECP10MDF [23] and the valence shell was described by cc-pVTZ-PP (10s11p9d1f)/[5s4p3d1f] basis set [23]. The calculations were carried out utilizing Gaussian 03 program package. The optimized structures from quantum chemical calculations at B3LYP/(B) level are given in Supplementary material [http://journals.isuct.ru/ctj/article/view/1799].

RESULTS AND DISCUSSION

According to the results of calculations, four optimized structures (conformers p-I - p-IV, see Fig. 2) of P-4C6H4X-H2P correspond to minima on the potential energy surface. Conformer I possesses the lowest energy (see Table 1), however the energies of conformers p-II - p-IV are only slightly higher. Conformation p-V corresponds to the saddle point of 4th order on the PES with imaginary frequencies describing rotation of the groups -C6H4X. Conformation p-VI also corresponds to the saddle point. The imaginary frequencies describe rotation of the substituents and out-of-plane distortions of macrocycle.

Note, that the different basis sets give the same qualitative picture of the relative energies of considered structures (Table 1). The molecular parameters of similar type calculated with use of the basis sets A-D possess close values. The maximum deviation of the bond length is 0.008 A that is close to the typical uncertainty of GED experiment. It should be mentioned that the use of basis sets C-D requires much more computational time as compared to A-B (Table 1). Therefore, the calculations of 4C6H4Br-H2P were only performed with use of basis set pVTZ (B).

Conformational analysis for ortho- and metaisomers of 4C6H4X-H2P was performed in the similar way as in our previous study of metal etioporphyrin-II [15,16]. Models I-V (Fig. 3) differ in the orientation of the halogen atom relative to the macrocyclic fragment. According to the results of calculations, the conform-ers m-I(I) and o-I possess the lowest energies (Table 3) for m-4C6H4X-H2P and P-4C6H4X-H2P, respectively.

Comparison of molecular parameters of similar type for ^-4C6H4F-H2P and ^-4C6H4Br-№P (Table 4) leads to conclusion that the nature of a halogen does not influence significantly the structure of entire molecule. Elongation of the bond C-X by ~0.6 Â in the Br-substituted molecule does not lead to noticeable deformations of macrocycle and, therefore, does practically not influence the relative energies of the conformers.

Fig. 2. Conformer models of P-4C6H4X-H2P Рис. 2. Модели конформеров и-4СбШХ-Н2Р

Table 1

Relative energies of conformers p-I - p-IV, conformations of p-V - p-VI of ^-4СбШХ-ШР, where X=F, Br, and relative CPU time for single point calculations

with use of the different basis sets Таблица 1. Относительные энергии конформеров p-I - p-IV, конформаций p-V - p-VI и-4СбШХ-ШР, где X=F, Br, и относительное время расчетов с использованием различных наборов базисных функций

Structure p-I p-II p-III p-IV p-V p-VI Rel. time a

X Symmetry C2v C2h C2h D2 D2h D2h C2v

ДЕ, kJmol-1(A)b 0.00 1.15 1.30 2.51 5.02 769.37 1.0

F AE, kJmol-1(B)b 0.00 0.43 0.50 0.86 0.99 767.43 6.1

ДЕ, kJmol-1(C)b 0.00 0.26 0.62 1.08 1.31 754.75 16.7

AE, kJmol-1(D)b 0.00 0.47 0.53 0.94 1.12 757.86 34.7

Bi AE, kJmol-1(B)b 0.00 0.42 0.50 0.91 1.10 760.45 -

Notes: a The ratio of CPU time of 5 cycles of SCF procedure within a single point calculation at different theory levels to 5 cycles of a single point CPU time of calculations using basis set (A); b (A), (B), (C), (D) basis sets are described in Computational details

Примечания: а относительное компьютерное время, затраченное на 5 SCF-итераций «Single point» расчета^ наборы базисных функции (A), (B), (C), (D) описаны в разделе Computational details

Table 2

Molecular parameters (internuclear distances, Â; angles, °) of conformer p-I of _p-4C6H4F-H2P calculated

with use of the different basis sets Таблица 2. Молекулярные параметры (межъядерные расстояния, Â; углы, °) W-4C6H4F-H2P (конфор-мер p-I), рассчитанные с использованием различ-

B3LYP/basis sets

Parameter (A) (B) (C) (D)

Ni-Ca (1) 1.367 1.364 1.362 1.361

Ca-Cp (1) 1.460 1.458 1.456 1.456

CP-CP (1) 1.354 1.351 1.348 1.349

Cm-Ca (1) 1.412 1.408 1.406 1.406

Cm-Ca (2) 1.406 1.401 1.399 1.399

Ni-Hi (2) 1.014 1.011 1.010 1.010

Ni-Ca (2) 1.376 1.374 1.372 1.372

Ca-Cp (2) 1.434 1.432 1.430 1.430

CP-CP (2) 1.369 1.367 1.364 1.364

Cm-C1 1.497 1.499 1.496 1.497

C1-C2 1.404 1.399 1.397 1.397

C1-C3 1.405 1.399 1.397 1.397

C2-C4 1.394 1.392 1.390 1.390

C3-C5 1.394 1.392 1.389 1.390

C4-C6 1.390 1.385 1.383 1.383

C5-C6 1.390 1.385 1.383 1.383

C-F 1.349 1.355 1.349 1.351

Ca(2)-Cm-C1 -C2 65.3 72.9 71.9 72.4

Ni-Ca-Cp (1) 110.9 110.7 110.7 110.6

Ca-Cp-Cp (1) 106.3 106.4 106.4 106.4

Ca-Cm-Ca 125.2 125.4 125.3 125.4

Ni-Ca-Cp (2) 106.5 106.4 106.4 106.4

Ca-Cp-Cp (2) 108.2 108.2 108.2 108.2

С j -HalogcnoplicnyLeroiipM-CtH-iX)

Fig. 3. Conformer models of w;-4C6H4X-H2P, о-4СбН4Х-Н2Р. Top view: the orientation of the X-atom (X=F, Br) with respect to the plane of the porphyrin macrocycle: (black)—above the plane,

(white)—below the plane Рис. 3. Модели конформеров .-4C6H4X-H2P и 0-4C6H4X-H2P. Вид сверху показывает ориентацию атомов X (X=F, Br) относительно плоскости порфиринового макроцикла: (черный) -над плоскостью, (белый) - под плоскостью

Table 3

Relative energies of conformers of m-4C6HX-H2P and

0-4C6H4X-H2P, where X=F, Br Таблица 3. Относительные энергии конформеров м-4C6H4X-H2P и Q-4C6H4X-H2P, где X=F, Br

X m- isomer m-I(I) m-I(II) m-II m-III m-IV m-V

symmetry C2 D2 Cl C2h C2h C2v

F AE, kJmol-1(B)a 0.00 0.67 0.21 0.40 0.5S 0.40

Br AE, kJmol-1(B)a 0.00 0.57 0.17 0.36 0.56 0.36

X o- isomer o-I o-II o-III o-IV o-V

symmetry D2 Cl C2h C2h C2v

F AE, kJmol-1(B)a 0.00 0.71 0.50 0.53 1.65

Br AE, kJmol-1(B)a 0.00 0.76 0.65 0.73 1.6S

Analysis of the sensitivity of the GED method to the determination of the conformational and isomeric composition of the 4CHX-HP (X=F, Br) vapor

In order to assess the ability of GED method to distinguish between conformations of ^-4C6HX-H2P molecule, a series of calculations of the model radial distributions curves f(r) was performed using results of B3LYP/(B) calculations. Vibrational amplitudes and corrections to the internuclear distances at the estimated temperature of GED experiment of T = 600 K were calculated with the use of VibModule program [24] (second approximation) on the basis of the force field obtained from quantum chemical calculations at B3LYP/(B) level.

Note: a (B) basis sets are described in Computational details Примечание: a базисные функции (B) описаны в разделе Computational details

Table 4

Comparison of structural parameters (internuclear distances, A; angles, °) for 4C6H4X-H2P (p-, m-, o- isomers,

X=F, Br) from B3LYP/(B) calculations Таблица 4. Структурные параметры (межъядерные расстояния, A; углы, °) 4C6H4X-H2P (и-, м-, o- изомеры),

Parameter X=F(p-I conf) p-iso- X=Br(p-Iconf.) p- X=F (C2) m- X=Br (C2) X=F (D2) o- X=Br (D2) o-

mer isomer isomer m-isomer isomer isomer

Ni-Ca (1) 1.364 1.364 1.364 1.364 1.363 1.363

Ca-Cß (1) 1.45S 1.45S 1.45S 1.45S 1.45S 1.45S

Cß-Cß (l) 1.351 1.351 1.351 1.351 1.351 1.351

Cm-Ca (l) 1.40S 1.40S 1.40S 1.40S 1.406 1.406

Cm-Ca (2) 1.401 1.401 1.401 1.401 1.399 1.399

Ni-Hi (2) 1.011 1.011 1.011 1.011 1.011 1.011

Ni-Ca (2) 1.374 1.374 1.374 1.374 1.373 1.373

Ca-Cß (2) 1.432 1.432 1.432 1.432 1.432 1.432

Cß-Cß (2) 1.367 1.367 1.366 1.366 1.366 1.366

Cm-Cl 1.499 1.49S 1.499 1.499 1.499 1.500

C1-C2 1.399 1.399 1.399 1.39S 1.400 1.401

C1-C3 1.399 1.399 1.399 1.399 1.393 1.400

C2-C4 1.392 1.393 1.392 1.392 1.392 1.390

C3-C5 1.392 1.392 1.3S5 1.390 1.3S7 1.393

C4-C6 1.3S5 1.390 1.393 1.393 1.393 1.392

C5-C6 1.3S5 1.390 1.3S5 1.390 1.391 1.391

C-X 1.355 1.913 1.356 1.915 1.354 1.916

Ca2-Cm-Cl -C2 72.9 72.5 73.S 74.2 S6.3 S9.9

Ni-Ca-Cß (l) 110.7 110.7 110.S 110.S 110.S 110.S

Ca-Cß-Cß (l) 106.4 106.4 106.4 106.4 106.4 106.4

Ca-Cm-Ca 125.4 125.4 125.5 125.6 125.7 125.7

Ni-Ca-Cß (2) 106.4 106.4 106.5 106.5 106.5 106.5

Ca-Cß-Cß (2) 10S.2 10S.2 10S.2 10S.2 10S.1 10S.1

The results of the calculations are shown on Fig. 4 and 5 (note, that the difference curves Af(r) were calculated relative to 1st curve corresponding to conformer p-I of p-4C6H4X-H2P: A f(r) = fj(r)-fi(r)).

The deviation of 7-th curve from 1st curve was characterized by disagreement factor:

RfJ =

Ti=i(s^(si)model 1 — s^(si)model j)2

between the theoretical molecular scattering intensities corresponding to different models (Rfj is disagreement factor; sM(si)model 1 - theoretical molecular scattering intensities for conformer p-I; sM(si)model j - theoretical molecular scattering intensities for corresponding conformer or isomer). The difference between f(r) curves in the case ofp-4C6H4F-H2P (in the ranges ~3.1-3.6 A and ~4.4-4.8 A) molecule is caused by change of distances Cph...Cporph due to different orientation of the halogenophenyl groups relative to the porphyrin core: the torsional angles x(Ca2-Cm-Ci-C2) are: 72.9° (p-I) and 81.3° (p-IV); 72.5° (p-I) and 80.1° (p-IV) for 4C6H4F-H2P and 4C6HBr-H2P, respectively. The analogous study for copper and zinc etioporphyrins-II [15,16] yielded the values of Rf<1.1% with the values of relative energies between the conformers being as low as ~0.3 kJ mol-1.

An attempt to distinguish between the isomers of 4C6H4X-H2P (ortho-, meta-, para-) was also made.

According to the difference curves Af(r), the ortho- and meta-isomers of 4C6H4X-H2P can be quite well distinguished from the most energetically favorable para-isomer. The differences are caused by significant changes in the distances between non-bonded atoms X...X, N...X, C...X and C...C. The bond lengths in the porphyrin core and phenyl rings are almost the same in the para-, ortho- and meta-isomers (see Table 4). Note, that the differences in f(r) between the isomers are much more pronounced in the case of 4C6H4Br-H2P due to higher scattering ability of the Br atom as compared to F.

According to the results of theoretical modeling performed in the present study, bond lengths and bond angles in the macrocyclic core and halogen-substituted phenyl rings are almost the same values in all conform-ers of p-4C6H4X-H2P considered. However, the changes in the distances between non-bonded atoms influence the model molecular intensities sM(s) and therefore an attempt can be made to distinguish between the con-formers based on the experimental GED data. It should be noted that this problem is at the limit of the possibilities of GED method and only the effective position of halogenophenyl groups are apparently refinable. At the same time, bond lengths and bond angles can be refined with a typical accuracy of GED method. Therefore, the geometry structures of macrocyclic core and halogenophenyl rings can be reliable determined.

-----3

1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1—1 0 2 4 6 8 10 12 14 16 18 20 22

r, A

Fig. 4. Comparison of theoretical radial distribution functions f(r) of 4C6H4F-H2P models: 1 - conformer p-I, 2 - conformer p-II, 3 - conformer p-III, 4 - conformer p-IV, 5 - m-I(I) conformer of m-iso-mer, 6 - o-I conformer of o-isomer; comparison of differences functions Af(r) concerning 1: 2 - conformer p-II (Rf =2.36 %), 3 - conformer p-Ш (Rf =2.75 %), p-4 - conformer IV (Rf = 5.08 %), 5 - m-I(I) conformer of m-isomer (Rf =4.98 %), 6 - o-I conformer of o-iso-mer (Rf =5.86 %). Molecular parameters were calculated at B3LYP/(B) theory level Рис. 4. Сравнение теоретических функций радиального распределения f(r) для 4C6H4F-H2P: 1 - конформер p-I, 2 - конформер p-II, 3 - конформер p-III, 4 - конформер p-IV, 5 - m-I(I) конформер м-изомера, 6 - o-I конформер о-изомера; разностных функций Af(r), рассчитаны относительно 1: 2 - конформер p-II (Rf =2,36 %), 3 - конформер p-III (Rf =2,75 %), 4 - конформер p-IV (Rf =5,08 %), 5 - m-I(I) конформер м-изомера C2 (Rf =4,98 %), 6 - o-I конформер о-изомера (Rf =5,86 %). Молекулярные параметры рассчитаны в приближении B3LYP/(B)

-3

-.------

I-1-1-■-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-■-1-1-1

0 2 4 6 8 10 12 14 16 18 20 22

r, A

Fig. 5. Comparison of theoretical radial distribution functions f(r) of 4C6H4Br-H2P models: 1 - conformer p-I, 2 - conformer p-II, 3 - conformer p-III, 4 - conformer p-IV, 5 - m-I(I) conformer of m-isomer, 6 -o-I conformer of o-isomer; comparison of differences functions Af(r) concerning 1: 2 - conformer p-II (Rf =2.15 %), 3 - conformer p-III (Rf =2.51 %), 4 - conformer p-IV (Rf =6.09 %), 5 - m-I(I) conformer of m-isomer (Rf=17.33 %), 6 - o-I conformer of o-isomer (Rf=18.50 %).

Molecular parameters were calculated at B3LYP/(B) theory level Рис. 5. Сравнение теоретических функций радиального распределения f(r) для 4C6H4Br-H2P: 1 - конформер p-I, 2 - конформер pII, 3 - конформер p-III, 4 - конформер p-IV, 5 - m-I(I) конформер м-изомера, 6 - o-I конформер о-изомера; разностных функций Af(r), рассчитаны относительно 1: 2 - конформер p-II (Rf =2,15 %), 3 - конформер p-III (Rf =2,51 %), 4 - конформер p-IV (Rf =6,09 %), 5 - m-I(I) конформер м-изомера (Rf=17,33 %), 6 - o-I конформер о-изомера (Rf=18,50 %). Молекулярные параметры рассчитаны в приближении B3LYP/(B)

ACKNOWLEDGEMENTS

The reported study was funded by RFBR according to the research project № 18-33-01199. The

research was carried out using the equipment of the

Center for collective use at Ivanovo State University of

Chemistry and Technology.

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Поступила в редакцию (Received) 10.12.2018 Принята к опубликованию (Accepted) 28.11.2019