MÖSSBAUER EMISSION SPECTRA OF 119mSnCl2 ADDUCTS WITH SOME OXYGEN AND NITROGEN COMPOUNDS

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MÖSSBAUER EMISSION SPECTRA OF 119mSnCl2 ADDUCTS WITH SOME OXYGEN AND NITROGEN

COMPOUNDS

S. Ichiba, M. Yamada, H. Negita

To cite this version:

S. Ichiba, M. Yamada, H. Negita. MÖSSBAUER EMISSION SPECTRA OF 119mSnCl2 ADDUCTS

WITH SOME OXYGEN AND NITROGEN COMPOUNDS. Journal de Physique Colloques, 1979, 40

(C2), pp.C2-428-C2-430. �10.1051/jphyscol:19792150�. �jpa-00218524�

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JOURNAL DE PHYSIQUE Colloque C2, supplkment au no 3, Tome 40, mars 1979, page C2-428

MOSSBAUER EMISSION SPECTRA OF 119m

SnC1,ADDUCTS

WITH SOME

OXYGEN

AND

NITROGEN COMPOUNDS

S. Ichiba, M. Yamada and H. Negita

Department of Chemistry, PaeacuZty of Science, Hiroshima University, Hiroshima 730, Japwz

Rhsum6.- Des experiences de source Mksbauer ont Qt6 rGalis6es sur le systsme

"

g m ~ n ~ 1 2 addition6 de compos6s contenant de 110xyg2ne ou de l'azote. Les effets chimiques de la reaction nucleaire sont l'apparition d'une faible proportion de l'espsce aliovalente oxyd6e snb+ losque le ligand ajout6 est l'eau ou l'aniline; cette proportion devient trSs importante avec le dim6thyl sulfoxyde, le dipheny- le sulfoxyde, oxyde de pyridine ou les oxydes de picoline.

Abstract.- The ~gssbauer source experiments of " g m ~ n ~ 1 2 adducts with some oxygen and nitrogen containing compounds were carried out. For the chemical after-effects a small portion of the oxidized alliovalent species of sn4+ was observed in the spectra of the adducts with the ligands such as water and aniline, whereas a very large portion of the aliovalent charge state was observed in the spectra of the adducts with dimethyl sulfoxide, diphenyl sulfoxide, pyridine N-oxide, and picoline N-oxides.

1. Introduction.- A number of Miissbauer source experiments of the 'Igmsn containing compounds have been performed and the aliovalent species in the host crystal have been observed previously 11-41. Several models such as autoradiolysis, charge relaxation process, and Coulombic fragmentation have been pro- posed hitherto to explain the stabilization of the aliovalent species observed in the emission spectra 151. In the present study the ~Essbauer emission spectra of the " g m ~ n ~ l adducts with some oxygen or nitrogen containing ligands were measured and the correlation between the chemical after-effects of the preceding isomeric transition and the ligand molecules were investigated. Preliminary results have already been reported 161.

2. Experimental.- The adduct samples were prepared according to the method reported by Donaldson et al.

171. Mdssbauer absorption spectra confirmed these samples to be purely divalent. Both the absorption and emission spectra were measured at 20K by cooling the sample in a liquid helium flow type cryostat.The Mgssbauer parameters have been deduced from the com- puter-fitted Lorentzian curves to the absorption and emission spectra by the least square method.

3. Results and Discussion-.- Both the absorption and emission spectra of SnC12.2H20 labelled with

"

^{9 m ~ n}are shown in figure I (a). The emission spectrum was analysed as a superimposition of a doublet peak of sn2+ corresponding to the matrix species and a small peak of snsf resulting from the chemical after-effect. A small portion of sn4* was observed to almost the same extent in the spectra of the adducts with the ligands of (CsH5)3PO, CsHsOn, e t c . However, a large portion of the oxidized aliovalent

species was observed in the emission spectra of the adducts with the ligands of (CH3)zSO, (C6Hs)2SO, C5H5N0, and a,

B,

~-CH~C~HL,NO.

absorpl Ion

emlsston

Fig. l : Mgssbauer spectra of a) the SnC12.2H20 adduct and b) the SnC12.2(CsHs) SO adduct at 20K.

The spectra of SnC12.2(C6H5)2SO are shown in figure 2(b). The Miissbauer parameters of the absorption and emission spectra of the adducts with the oxygen com- pound ligands are listed in table I along with the ratios of the sn4+ peak area to total.

The stabilization of the small portion of sn4+

observed in the spectra of the adducts with oxygen containing ligands are explained by the oxidation of the decayed ion by free radicals created during the autoradiolysis of the ligands in accordance with the result of the water adduct reported by Friedt e t a l . 121. However, the large portion of the aliovalent species observed in the spectrum seems likely to be stabilized by the charge relaxation process or Cou- lombic fragmentation rather than autoradiolysis. The emission spectra of the adducts with the ligands of

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19792150

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a, B, and y-picoline N-oxide are shown in figure 2.

Table I : ~Essbauer parameters of the tin(I1) chloride adducts with some oxygen containing donor molecules.

1 1

l l

I Absorption I Emission ,

Compounds I I I I

I sn2+ I sn2+ sn4+

:

⁶

A r : s

^A

r

6

A

A(s~~+)

:

( m m l s ) (mm/s) (mm/s): (mm/s) (mm/s) (mm/s) (mm/s) (mm/s) A(tota1)

1 I

SnC12

:

^4.20 ^1.69

;

^4.16 ^2.71

1 l

SnC12.2H20

:

^3.68 ^1.25 ^1.44: ^3.68 ^1.79 ^2.52 ^0.31 ^0.63 ^0.13

I 1

SnCln

.

^CsHeO2

:

^3.66 ^1.74 1.33,: 3.66 2.06 2.70 0.94 0.13

1 l

:

^3.41

SnC12.2(CsH5) 3P0 l 1.61 1.04

:

^3.41 ^1.81 ^2.32 ^0.31 ^0.08

1

SnC12. (NH2) 2CO

;

^3.63 ^1.28 ^1.28

;

^3.62 ^1.71 ^2.61 ^0.39 ^0.83 ^0.10

l 1

SnC12 .2(CH3)2SO

:

^3.48 ^1.50 ^1.05

:

^3.47 ^1.76 ^2.53 ^0.84 ^1.46 ^0.48

1 I

SnC12.2(CsH5)2SO

:

^3.38 ^1.68 ^1.42

:

^3.37 ^1.83 ^2.54 ^0.69 ^1.28 ^0.68

l 1

SnC12 .CsHsNO

:

^3.42 ^1.39 ^0.91

:

^3.40 ^1.62 ^2.24 ^0.79 ^1.37 ^0.52

1 1

SnC12.a-CH3CsH4NO 3.34 1.47 1.09

:

^3.34 ^1.95 ^2.51 ^0.87 ^1.08 ^0.35

1 1

SnC12. B-CHsC5HrN0

:

^3.46 ^1.37 1.15: 3.46 2.00 2.39 0.69 1.12 0.45

l l

S ~ C ~ ~ . ~ - C H ~ C ~ H I , N O

:

^3.38 ^1.48 ^1.25: ^3.38 ^I^.64 ^2.79 ^0.72 ^1.03 ^0.56

l l

V e l o c i t y , mm S-'

Fig. 2 : Mzssbauer emission spectra of the 1'gm~n~12 adducts with picoline N-oxides at 20K

a) S ~ C ~ ~ . ~ - C H ~ C ~ H Z , N O ; b) S ~ C ~ ~ . B - C H ~ C ~ H Q N O ; c) S ~ C ~ ~ . ~ - C H ~ C ~ H L , N O .

From table I and figure 2, it can be seen that the yield of sn4+ species varies with the ligand molecu-

le, i . e . , with the position of the methyl group in

the ligand molecule. Then, the yield of sn4+ is sensitive to the electron density on the nitrogen atom in the ligand and increases with decrease of the electron density on the nitrogen atom because the methyl group has tendency to release an electron.

The Miissbauer parameters deduced from both the absorption-and emission spectra of the adducts with

some nitrogen containing ligands are tabulated in table 11. The absence of the oxidized aliovalent species in the spectrum of the pyridine adducts and others is consistent with the result of the bipyridine adduct reported by Friedt et aZ. /4/. The small portion of the oxidized aliovalent species observed in the spectra of the adducts with the ligands of aniline, o-chloroaniline, and o-anisidine will not be explained by autoradiolysis model because the radicals originated from aniline and its derivatives by radiolysis would be reducing as well as pyridine

and bipyridine.In those adducts, the yield of sn4+

is also sensitive to the electron density of the ligand molecule, because both the methoxy group and chlorine atom are electron attractive. Therefore, it seems likely that the stabilization of sn4+ observed in the emission spectra of those adducts are local phenomenon occured in the molecule such as charge relaxation or Coulombic fragmentation.

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c2-430 JOURNAL DE PHYSIQUE

Table I1 : ~Zssbauer parameters of the tin(I1) chloride adducts with ligands of aniline and its derivatives

I

ÎÎ Absorption I Î

I - ^I Emission

1

Compounds ¹I sn2+ snS+

i-

: S

A

r

⁶ ^A(s~'+)

(mm/s) (m/s> (m/s)

:

^(m/s) ^(m/s) ^(mm/s) ^(m/s) ^A(tota1)

References

/l/ Sano, H. and Kanno, M., Chem. Commun. (1969) 601.

/2/ Friedt, J.M. and Llabador, Y., Radiochem. Radio- anal. Lett.

9

(1972) 237.

/3/ Llabador, Y. and Friedt, J.M., 3 . Inorg. Nucl.

Chem.

35

(1973) 2351.

/4/ Sanchez, J.P., Llabador, Y. and Friedt, J.M., J. Inorg. Nucl. Chem.

2

(1973) 3557.

/5/ Wertheim, G.K., "The study of Crystalline Defects by ~Essbauer Effect, in the Electronic Structure

of Point Defects'' (North-Holland Publ. Co., Amster- dam) 1971, p.20.

/6/ Ichiba, S., Yamada, M. and Negita, H., Radiochem.

Radioanal. Lett.

35

(1978) 31.

/7/ Donaldson, J.D. and Nicholson, D.G., J. Chem. Soc.

A (1969) 145.