Научная статья на тему 'Analysis of the quadrupole coupling constants (nqcc) and chemical shifts from the Mossbauer spectra for the central atoms in compounds containing non-transition metals'

Analysis of the quadrupole coupling constants (nqcc) and chemical shifts from the Mossbauer spectra for the central atoms in compounds containing non-transition metals Текст научной статьи по специальности «Физика»

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Аннотация научной статьи по физике, автор научной работы — Poleshchuk O.Kh., Shanina Yu.A., Latosinaka J.N., Nogaj В.

Серия: Естественные и точные науки

in this paper the complexes of the Sn, 5b, Aland with organic ligands were obtained. Were round ibat in the case of organic ligands was a strait proportional relation between 5s and 5p-orbilal for the Sb end Sn atoms, whereas in the case of inorganic there is net found such a dependence. The explanation ol this difference is closely connected wilha multiple parameter character of the dependence of chemical shift on lhe cenlral atom charge. The obtained dependencies between Missbauer'a Chemical shifts and 5s end Sp-pcpuialwns of Sn and Sb atoms pointed to the same nature of the chemical shifts m any Sb and Sn compounds, which is independent on me kind cf lira ligand localised around the central atom

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Текст научной работы на тему «Analysis of the quadrupole coupling constants (nqcc) and chemical shifts from the Mossbauer spectra for the central atoms in compounds containing non-transition metals»

цналов ПТ исследуемых амальгамных процессов. Обобщение литературных источников [3-7, I I, 13-15] и анализ нашего экспериментальною материна показывает, что система ртуть водород ЯВЛЯСТСЯ крайне сложной металлнчес-кол системой, в которой могут существовать несколько форм водорода: гндрндиый (НёН, растворенный атомарный (Н)Нё и молекулярный (Н:)Нй водород и окклюдированный водород на поверхности твердой ртути Б электрохншгчсской практике при электролите водных растворов с ртутным электродом возможно образование газовых эмульсин водоро-и д рту I п.

ВЫВОДЫ

I. Методом инверсионной вольтамперомет-рни с ртутным пленочным о 1стгродом на фонах хлоридов 5-металлов зарегистрированы пики тока, связанные с окислением различных форм водорода в амальгамах: атомарного, гидрндно-го ¡1 мо кжулярного, образующихся при йагод ной поляризации электрода.

I. Обнаружен эффект раздвоения гшка ток:« ок1гслення амальгамы молекулярного водорода, обусловленный протеканием реакций ионизации водорода, находящегося в форме газовой эмульсии и гомогенной амальгамы.

Литература

1. Шанк Ф. Структуры дяпйныл еппзgsa M : Метаппурни*, 1973. С 425.

2. Галактжмнова H.A. Водород в метэчпах. М. Металлургия, ÎM7. 3Û4 с.

3. GmeNfi's Handbuch der Anorganischen Chenil. Quecksilber. N* 34 Bd. B-2.I.Verlag chemie. Gmbh., 1965. P. 3-15. 4 Кобозев H.И. Ц Ж. фи. химии. 1952 Т. 2Б Вып. t. С/112-134 (Выл. Э. С. 43А-4501

5. Птищын C.B. Н Ж. техн. физики. 1Э35. Т. 5. Вып 2. С. 329-341. 6 Smith F.В., Heinde H.U. // Canad. J. Chem. 1970. V. Ц. Nf t. P. 203-209. 7. Smdh F.R., Wells A.E. // Nature. 1967. V. 215. N 51 Q€. ?■ 1165-1166. В. Фрумкин A.H. Перенапряжение водорода. M.: Наука, 1ЭЯ8, 240 с.

9. Encyclopedia ol Elechûchemislry ol the elements / Ed. A.J. Bard N.J.-Basel. Mari«I Оеккаг, 1982. V. 9. p. A. Mercury IP. 2-229): Hyîrogen (P. Ш-53С),

10 Гладыше« В.П., Пили А.П., Сироешкина Т В. // Теория и практика амальгамных гтрадссое Алма-Ата.: KaafV. 197В. С. 59-70 fi Ковалева С.В Ц Вестник ТГПУ. Томск, 199Й. Вып. 2. С. 70-В1.

12. Pourtaix M. Allas d'equihbres electrociiimiques. Paris:' G8ulhier-Vel1us.1963. P. 124-131.

13. Гладышей В.П., Ковалева C.B. ff Ж общ. химии. 1995. Т. 55. выл. 11. С. 1761-1765.

14. Ковалева C.B., Гладьшнв 6.П. // Ж. общ. химии., 1996. Т.'66. Вып, U.C. 1761-1764.

15. Гладышее В.П., Ковалева C.B. // Ж общ. химии. 199$. Т. №. выл: 10. С. 1753

15. Вьщрэ Ф-, Ш ту лик К., Юласоеа Э. Инверсионная вольтамперометрия, М.: Мир, 1980. 260 с.

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17. Xamwa P.M.. Татауров В.П., Брайана Х.З. // Зав. ла15 я. 108Й. Т.'54 № 2. С 1-9.

ta, Афанасьев Б.Н. // Элеггрокимия. 1ЭЯ6. Т. 22. Вып. 1. С. 32-35.

19. Бендерский В.А., Криеенко А.Г. //Электрохимия. 1995. Т. 31. Вып. 10. С. 11ВВ-1196.

20 Коршунов В.Н. Амальгамные системы. М.: МГУ. 1990- 200 с.

21. Гладышвв В.П , Рубан Л.М., Кулешов В.А. // Кинетика процессов на окисно-металличесги* и амальгамных электродах. Алма-Ата: Наука, 1969. С. 112-119.

22. Калла» В.Я., ПацР.Г., Салихджанова P.M. ф. Вольтамперометрий переменного тока. M : Химия, I9B5. С. 140.

23. Lu W.. Baranski D.S. // J. Electroanal, Chem. 1992. V. 335. № 1-2. P. 105-122,

24 Ефимов ИХ. Пивмарова A.A., Назарова Е.В. и др. // Химия неорганических гидридов. М.: Наука, 1990. С. 203-204. 25. Резникова Л.А., Сазонова Е.В., Кабанов 6.Н. и др. // Электрохимия. 1987. Т. 23. Вып. 6. С. 827-831.

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O.Kh. Pokshuk% Vu. A. Shan inn*, JN. Latosinska**, B. Nogaj**

ANALYSIS OF THE QUADRUPOLE COUPLING CONSTANTS (NQCC) AND CHEMICAL SHIFTS FROM THE MÖSSBAUER SPECTRA FOR THE CENTRAL ATOMS IN COMPOUNDS CONTAINING

NON-TRANSITION METALS

"Tcrrsk P&dagogicai University, 'Institute of Physics, Adam Michiewcz University, Poznac, Poland

The aim of this paper was to explanation oT ihe correlation between the MOssbauer chemical shifts and charge localised on the central atoms- 'i hu

complexes of the Sn, Sbf AJ and J with organic ligands seem very interesting mode! compounds for the studies of the donor-acceptor interactions. Weha^e

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O.Kh Poleshiik. Yti.A. Sha)tina, J.N. Latosinska, B. Nogaj. Analysis o/ the (fuadrtipole coupling..

found that in the case of organic licands there is a strait proportional relation between 5s-and 5p-orbital for lhe Sb and Sn atoms, whereas in the cast; of inorganic there is not found such dependence. The explanation of this difference is closely connected with a multiple parameter character of the dependence of chemical shift on the on the central atom charge. The obtained dependencies between MOssbauer's chemical shifts and 5s- and 5p-populations of Sn and Sb atoms pointed to the same nature of the chemical shifts in any Sb flnd Sn compounds, which is independent on the kind of the ligand localised around the central atom.

INTRODUCTION

The large amounts of the compounds were studied by NQR, Miissbauer and X-Ray electron, X-Ray fluorescence spectroscopies [1-12]. Some qualitative conclusions related to the bond nature were found or the basis of these studies. It w as not dearly explain the correlation between Mflssbauer's chemical shift (S) for tiie Sn and Sb atoms and the donors ability of the ligand. In some papers we found that the 6 decreases with the decreasing of the ligand's electron donor properties [5-7], while in the other we found that the 6 decreases with increasing of the iigfmd's ;d:ili;> [I 3]. On liu- other hand the correlation belween the experimental QCC values and calculated by semiempirical and ab initio metnods for Sn. Sb, Al and 1 compounds had not been received [13. 14].

The aim of this work was to investigate (he parameters describing the electronic structure of these compounds (population of the central atom orbitals. charges on the acceptor, Mossbauer shifts. QCC) and explain the differences in the case of compounds containing Sb and Sn atoms.

The calculations were performed for some Sn, Sb, Al and I molecules by ab initio met hods and for eight model SnCI L, and twelve SbCl,L complexes by PM3 method I Ik ab nitio calculations were carried o.ut with the program packages GAMESS, MOLCAS. HONDO and GAUSSIAN 94. run on an IBM RS/ 6000 work station in the double polarised TZ2P basis set. Results were obtained on the Hh74~3lG, MP2/6-31IG** and MP2/ccpVZ levels of the theory. The l | Iinh lipoid Liiupling 11 - - a rv -. f. Sn . N':v t'I, Mud I atoms were calculated on the basis of the eigenvalues of the electric field gradient tensor from ab initio, and l:> PM3 method. The full optimization was performed and the parameters describing geometry (i.e. bond lengths, except central atom - ligand bond length, angles and torsion angles) were found. The calculations [15] for SnCl+l, and SbC1}L complexes by PM3 method were performed for the different Sn(5b)-I. bond lengths (which vary from 2.0 to 2.7 A)

RESULTS AND DISCUSSION

1 he NQCC constants for the central atoms calculated using the extended basis 6-31IG** as well as cc-pVTZ with pseudo-potential were much lower th an the experimental data (Table I). Calculations performed using the 4-31G basis set for the all electrons of the centra! atoms led (o NQCC much closer to the experimental ones. The NQR frequencies calculated by ab initio method (in 6-31LG** basis) for the terminal halogen atoms are well correlated with the experimental results. We concluded that application of the pseudo-potential by HONDO and GAUSSIAN packages did not lead to appropriate NQCC values for the non-transition atoms containing many electrons, such as Sn. Sb and I. The QCC values for I collected in Table 1 were calculated on the basis of Townes-Daif ey approximation because of the

::'li.v:. approach e vci> low alues. A.-... agreement with the experiment was obtained fot NQCC values calculated for the central atoms of some compounds by the PM3 method (on the basis of TOwnes-Dailey approximation). "1 he results from Table I point to the usefulness of PM3 method for s-and p-populatlon of Sn and Sb atoms analysis.

First of all the calculations by PM3 method point to increase of the positive and negative upon the increasing of the Sn(Sb)-L bond length (e.g. Fig. 1). Such kind of changes of the effective charges on Sn, Sb and CI atoms is caused by increasing the donor-ligand ability what is in a good agreement with the paper [7].

This conclusion was also confirmed by the Snkm shifts form the X-Ray emission spectra for SnX4L. {X=CI. Br. 1) [8-IÜ] as well as the inner Sb levels in the X-Ray electron spectra of SbCl.L complexes [18]. The increase of the qSn(Sb) obtained in papers [Ü-I0] should provide to the-qn increase during complex formation, This is in a good agreement with the NQR results described in details in (he paper [7].

It wras shown in Fig, 2 (which is the example for the only one of these complexes) that with the decrease of the Sn(Sb)-L distance the "CI-NQR frequency decreasing. Por the axial and equatorial atoms in the cis complexes these changes are proportional. It Is well knowr^ (from thcTownes-Dailey approximation [19]) that the JlCI-NQR frequency depends rather more on ionic character of the bond than on multiple of (he bond.

We used the calculated charges on the Sn, Sb and CI atoms. 5s-fmd 5p-popal at ions ofSn and Sb atoms (Ns, Np> as well as the experimental [16, I?] and calculated chemical shifts (with respect to CaSnO.) and found the correlation dependencies between these parameters. The values of the chemical shifts were obtained from the correlation relations written below: for the SnCI^Lji

Table 1

QCC values of the central atoms and HCI IrenjuendiS, catenated in the ctiffereni basisesfor Sn and Sb compounds

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(ÛMninind .. Noclcûà c'Oq^CirilVttlï! r Otinfv Cl}"' pUil в«" MfJJtlH

»Cli mSb 84,7 71 12 STO-3G G A MESS

"'Sb uä 24 3Ù,I(«() ä-3i IG" HONDO

mSfc 84,7 32,2 (eq) 27,йЦм) 30,S(eq) SP PM3

"a 37,^)42,3^1 SÏO-3G GAM ESS

"CI 30.1 Still) 27.3f(ax) ibJtlC 1ION DO

:'C5 ÎOJSÎtoi 17.SifanV30.ISf mî ЬЩ PM1

SbjClm "4h 1B7 45 130 6-31 IG" HONDO

1 'Sb 1ST IK.Oftr) 32j6tiK) 29r4(cqj SP PM3

"CI tl;76(brj 30j*isBt) 27Jt>l0$ Wçi) 4i(ax) 39(eq] 6-3110 I IONDO

IS.ÎÔ^idiÎfa^l-Î .lÉIeof SP PM3

lei 3016 2374 6-3110" GAUSSIAN

Pi 3016 26J4 ■SP ■ AMI

3016 230? SP

'VI 37,î 6-3110" GAUSSIAN

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'Vi 53,8 SP AM'

"u m 44,7 SP PM3

ICIPy 1095 3016 6-31 ю GAUSSIAN

j:tJ mf 244$. SP PM3

mi 27Î4 SP AMI

"VJ 21,0 29.2 ci-31 ig' GAUSSIAN

BCi IKö 4M SP PM3

"CI 2|rt 41A SP AM!

йЙ» 3034 3232 SP PM3

fl 3034 2186 . SP AM!

"Ci !3.7{br)' ftbfl 24,91103 SP FM3

uci 1 î.^ibfWî.7ttcrl ■1 К :т1 3<J.2ilci> SP AMI

SbCi^Md ' 'so ISÉ 15 6-31 IG HONDO

'■Sb LÎS 16 SP PMJ-

l,a 14-26 H,A HON 1X1

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*CI 24-26 3.1 SP ?M3

mSb 214. .. _ 1*3 ÏTO^Sé: GAMESS

SbCbMeCH 216 33 SP PM3 ■

Vi 36,1 46,6 STO-3Ö GAMESS

"CI 26.1 37-4 SP PM3 ■ :

SnCN2SMc: ' 'Sn n 1 ,2 6-31 !G" HONDO

"CI 1)1,4 21.4 6-31 ic" HONDO

(i ia/t 23 SP ■ PM3

SnCUtw ,vSn .16 39 37 6-J1C ■ MOLGAS

'ti 18-20 ' 28 SP ■ PM3

SuCIjüjj} "CI 24.! 23,9 je" , u >n r k i

34.1..... 33 SP ■ i>№ ■

Äliftu »AI 13. 8 11.1 .sp PM3

albralts® "ai S.Û5 1.43 SP i'M3

AlUr-Pv "ai 0.43 qjw______ sfr ■ ''Ml.

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aifjfciJ :,л1 1 ft uiVpi. GAUSSIAN

"a! - 15,1 STO-3G GAMESS

Vi 36-27 26,8 ocvpi GAUSS! AN

26-2? 28. S STO3G GAMIZSS .

AlFiSPCh tu - 1,2 tcvpï GAUSSIAN

"ci li- 30 28.3 gaussian

alf^tat "ai : 9A uivpi GAUSSIAN

AlBnKb naî 1Vl 4-20 l(U STO-3G Gh\MESS

26-37 193 STO-3G CTAMfSS

trans fi=?.6Ns-2.2Np-4.2 (r=0.81, s=0.1), (la) cis 6 =5,7Ns-3.1Np-l.G (r=0 85, s=0.05); ( k) for the SbCi.L:

6 =32.5Ns-5.2Np-52,l <r=0.77, S=0.1). (I) In the fig. 3 (which is the example for the only one of these complexes) is shown the dependence uf 6 values on ilh(Sn)-L bond length for ¿hi; complexes with optimised Sn(Sb)-L bonds. DoubL; parameter dependencies of the donor-acceptoi; boftd length on Ns and Np population of the Sn

atom are completely different for the cis and trans complexes SnCl^Lj. în the cis complexes the contribution of the 5p-population exceeds 5s-population, while for the trans complexes, the situation is opposite. The equations (l)-(2) pointed aiso to a higher contribution of the Sp-pbpulalion on Sn atom to the calculated M&ssbauér chemical shift. For the SbClj.L complexes there is not such a difference between trans-and cis-compIe.KiS. Moreover, the contribution of the Sb 5s-population

O.Kh Poleshuk, Yu.A. Shanina, J.N. Laiasinska, B. Nogaj. Analysis of the quadrupole coupling..

Tabie 2

T"; coefficients of Ihe doubls parameter equji.ons 5 ) f:f Ihi studies complexes aNs+bNp+c

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(iini|kiiii)it i J> u; |- |i

Sbi 1,

MeCNW 1ir0 3L5 0.02

iVlr:l: .1 C>,4 11.01

15,7 £¡4 20. 3 0.01

M^SOiuis) 14, S 2.J -29,4 0,9*13 H>i

PWIiKi*) -27,8 7,0 39,6 (►■999 0.01

■15. H 7.0 v.m 0,0 i

(CHi^.toii) ■41.9 10,3 69.fi 0.9H7

SOCht^is) -17yD 5.4 12,7 0,02

MiNOi(tr»na) 5./ S,fi 0,997 o,oi

CCIiCN-L.^ S3 7.3 ■ 17.0 0,™ 0.01

7.« i.o -22,0 o.yva 0.01

MC)S(t№ii) 21,i 32.2 0.960 0.06

SnCl,

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UcCXtyfel -9,0 0.997 0,02

Me,NtOIi(lrin.^ ■0,8 0,9« 0,05

SbCt^tisJ 0 ■2.1 0,99^ 0,01

\lrfSOfds5i -d.i 0,999 0.01

MiiPiLriiTO ijj -2.1 -t.Ei №) 0.01

J^iiinsl tii 0,1 0,993 Ojpt

miisctni '. j l.S -V -2.5 0,999

POCI^tiiJ 0.5 : i 0,991) 0.01

i.s

nr.

-03

—---- —-————,

R1 =0.9944

,9 2 2.1 22 2,3 2,4 2.5 2

------- qOO, 1107f(Sb-Cl)-0,5361 R ^1=0,232 'j&e№l,D225 FT =0.0671

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38. 36. 34

*

St 3<H s

JZ

u

tf =0.9901

241 v=3,4796rtSn.£Vi+18,5G1 R =0,993-1

sol--- ,

L distanr^.A

i 1 The; dependsix belwser the charyei on the Sn{Sbj and Ci atoms and Sn(Sb) -L bond lendinglfe h; SnCI, 2DVF and Sb'QIjDMP compt^a

1,9 i 2,1 2 2,3 2,4 :< 2.C Sii(Sb)-L distar.ea.A

2,7

1,B

0,5

-05

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—^ qsrtt-o 47c3ris^-c-;)+2 s37ti ff1 -"ci ,9344 1 1

-.0 2 2.1 a3 2,3 2.4 2,5 2,6 2

---------- r!

Sfi(Eb)-L dislanoe A

Fig. 3 T^e correlations between Uie Missbauer chemical thif;s and 5n(Sb] bond length:; for SnCt( 2DMF and SbtJ ,DMF complexes

Fig. 2 ' he ^Cl-NQR ffeqoanciflS v^'Sus 5n(Sb) ^cr.i le.- qihs to; inCi.iMeCN and SjppijMeCN complexes

excecds Sb 5p~population to the calculated Mossbaucr chemical shift. We have concluded the same from the correlation dependence between the same parameters but obtained on the basis oT experimental data (equation 2).

In our opinion, this is the result of the higher difference between energies of the 5s and 5p Jjevels for Sb than those for Sn. The contribution of the 5p SbfSilj atom urbilals to the chcmical bond is lower in the case of Sb than similar in the case of Sn complexes.

From the results of the calculations one can see that Mossbauer chemical shin increase with the Sn(Sb)-L bond length increasing (Fig. 3 for example). The double parameters of the dependencies (Table 2) can satisfactory describe the

correlation t#ltycen the chemical shift and ¡lie donor ability of the ligands,

Thesimiiar double parameter dependencies were found Гот the inorganic compounds SnX^, where X=H, F, CI, Br, J; SnClt2. X=F, CJ, Br, I; SnX^Y7, X=C1, Br, I, Y=F,CI, Br, I); SnX;iX=Cl, Br), (with respect to 6-5nOr) 12-frj.

S= I-9N s+d.2Np-1,7(г=П .61 ,s=0.3> (3)

as well as for the inorganic and orgunometallic compounds SbMenXJn (X=F, CI, Br, J; n=0-3); Sb MenX^ (X=F, Gl, Br, I; n=0-5); SbPh^X, (X=C I, Br, t) (wi№ respect to InSb) [14, 20]: 5 = -61Ns+0.4Np+l 15 (r=C.58, s=3.5). (-1)

The obtained relations between Mossbauer's chemical shifts and 5s and 5p-populattons ofSn and Sb atoms pointed to the same nature of the chemical shifts in any Sb and Sn compounds. These models studies provides also to a conclusion that Mossbauer's chcmical shift should decrease with

increase of the donor ability of the ligands in the series of the SnCljL, and SbCI5L complexes.

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CONCLUSION

It seems very important that it is possible to use the chemical shift to the estimation (if the donor ability of the Jigand Moreover these relations can be interpreted as the dependence of the chemical shin on charge on the central atom. The population of the 5s-and 5p-changes in proportion for the Sn and Sb atoms and chemical shift depends on the charge on Ihe central atom for the studied complexes. For the other compounds of the Sb arid Sn (eqs. 3 - 4) the relation between Ns and Np in the series of'tht compound* is not strict proportional This ¡s due to the reason that chemical -shift depends on more than only charge on the central atom, which is confirm by the equation 3-4 and relativelv low curve fit standard error.

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УДИ541 <19

О.Х. Полешук, В.ф. Усоя, ЮЛ, Шаишш

ИССЛЕДОВАНИЕ ЗАВИСИМОСТИ МЕЖДУ ЭЛЕКТРОННЫМ СТРОЕНИЕМ И СПЕКТРАЛЬНЫМИ ПАРАМЕТРАМИ В КОМПЛЕКСАХ ПЯТИХЛОРИСТОЙ СУРЬМЫ

С ОРГАНИЧЕСКИМИ ЛИГАНДАМИ

I

Томский государственный педагогический университет

В настоящее время нет теории, позволяющей количественно объяснить стабильность ЭДА-коиндексов и определить электронодоиорные и электроцоакцепторные свойства молекул. Естественно, 41 о свойства, проявляемые молекулой донора в реакции комплекс о образования, будут

в определенной мере зависеть от свойств акцептора, и наоборот, свойства акцептора в этой реакции в какой-то мере определяются свойств аил донора. Для понимания характера этой взаимосвязи н природы донорно-акцепгторного взаимодействия весьма важно выяснить, какие факторы