- Email: [email protected]
Complexes of lanthanide methanesulphonates with thioxane oxide: Comparison with tetramethylene sulphoxide
~o~~~al of the bus-gammon
Marls,
94 (1983) 309316
309
COMPLEXES OF LANTHANIDE METHANESULPHONATES WITH THIOXANE OXIDE : COMPARISON WITH TETRAMETHYLENE SULPHOXIDE*
L. B. ZINNER and E. CASTRO
DE SILVA
In&i&to de Quimica, Uniuersidade de SGo Pa&, (Brazil)
Caixu Postal 20.780.01498 Scio PauEo, Sk Paul0
(Received January 27,1983)
Summary Rare earth methanesulphonates (ms) react with thioxane oxide (tso) to give compounds with the composition Ln(ms&*3tso (Ln z La-Lu, Y). These compounds were isolated and their properties were studied. The molar conductance measurements are compatible with non-electrolytic behaviour. The vibrational spectra in the IR region indicate that tso coordination occurs through the sulphoxide group and that the ms ions are coordinated. X-ray powder patterns differentiate three types of isomorphous compounds: lanthanum to gadolinium; terbium and dysprosium; hohnium to lutetium and yttrium. The visible absorption spectrum of the solid neodymium compound suggests that the 4f orbitals are weakly involved in bonding and that the Nd3+ ion is not in a cubic site. The fluorescence spectrum of Eu(ms),*3tso is tentatively interpreted.
1. Introduction The methanesulphonate (ms) anion derived from the corresponding strong acid may act as a non-coordinating agent or as a monodentate, bidentate or tridentate ligand. To study its behaviour towards the tripositive lanthanides, the hydrated and anhydrous salts have been prepared [1, Z] and research involving these salts in relation to ligands containing oxygen as donor atom has been initiated. Complexes with tetramethylene sulphoxide (tmso) [3], 2-picolineN-oxide [4] and hexamethylphosphoramide (hmpa) [5] have been prepared and studied. Here we present the synthesis and characterization of the adducts between lanthanide methanesulphonates and thioxane oxide (tso). Some properties of the complexes are compared with those reported for the tmso compounds [3 1. *Paper presented at the Sixteenth Rare Earth Research Conference, Tallahassee, FL, U.S.A., April l&21,1983. 0
The Florida State University,
Elsevier Sequoia/Printed
in The Netherlands
310
2. Experimental
details
2.1. Preparation The anhydrous ms salts [2] were treated with an excess of tso (prepared from 2,4-thioxane (Aldrich) by oxidation with hydrogen peroxide solution [S]). The mixture was gently warmed and stirred with a glass rod. The viscous solution formed was treated with a large excess of anhydrous acetone to precipitate the adducts, which were filtered, washed with acetone and dried in uacuo over anhydrous calcium chloride. The compounds are hygroscopic, particularly those from gadolinium to lutetium and yttrium, and must be handled under anhydrous conditions. 2.2. Analysis and measurements The analytical data for the lanthanides were obtained by complexometric titration [7]. Carbon and hydrogen were determined by microanalytical procedures. Electrolytic conductance measurements were performed at 25.00 f0.02 “C using a bridge and cell (K, = 0.1070s cm-‘) obtained from Leeds and Northrup. X-ray powder patterns were obtained using a Norelco instrument and Cu Kct radiation. IR spectra were recorded on a Perkin-Elmer model 180 spectrophotometer. The absorption spectra of the neodymium adducts were recorded using a Cary 17 spectrophotometer. The emission spectra of the europium compounds were measured using a Zeiss ZFM-4 spectrofluorometer (excitation wavelength, 394 run). The refractive index of the methanolic solution was determined using a Bausch and Lomb Abbe-type refractometer.
3. Results and discussion The rare earth methanesulphonates Ln(ms), react with tso to give microcrystalline complexes of Ln(ms),*3tso stoichiometry. The complexes prepared, together with their analytical data and some physical properties, are listed in Table 1. The X-ray powder diffraction patterns are well resolved. The interplanar spacings and line intensities show that they are crystalline and reflect the presence of three isomorphous series: lanthanum to gadolinium compounds; holmium to lutetium and yttrium terbium and dysprosium compounds; compounds. The molar conductivities of solutions of the complexes (10V3 M in methanol) indicate non-electrolytic behaviour (Table l), implying that the ms anions are coordinated to the metal ions [S]. Some characteristic IR absorptions of the ligand bands are included in Table 2 and were assigned according to ref. 9. The coordination of the tso to the rare earth ions results in a red shift of the 1013 cm- ’ band which is assigned to v(S0). Shifts and/or splittings of the bands corresponding to both antisymmetric and symmetric C-O-C vibrations were also found. This suggests that the ethereal oxygen is also a ligation site in some of the complexes.
DY Ho Er Tm Yb Lu Y
La Ce Pr Nd Sm Eu Gd Tb
Ln
22.76 22.54 22.91 22.56 22.54 22.22 22.63 22.38 22.22 21.53 21.83 21.75 21.86 21.79 24.09
17.51 17.76 17.96 18.05 18.84 19.19 19.57 19.03 20.33 20.07 20.28 20.62 20.67 21.23 12.23
22.96 22.93 22.91 22.81 22.63 22.59 22.44 22.39 22.29 22.23 22.16 22.12 22.01 21.95 24.53
17.71 17.83 17.91 18.26 18.89 19.05 19.58 19.75 20.11 20.31 20.58 20.74 21.14 21.32 12.10
Experimental
Theoretical
Theoretical
Experimental
c
data for the lanthanides
Ln
(%)
melting point and conductance
Composition
Analytical,
TABLE 1 Ln
Experimental 4.45 4.55 4.44 4.46 4.50 4.29 4.27 4.57 4.86 4.82 4.65 4.33 4.25 4.40 5.04
Theoretical 4.24 4.23 4.23 4.21 4.17 4.17 4.14 4.13 4.12 4.10 4.09 4.08 4.06 4.05 4.53
H
185 175 170 165 155 150 145 135 125 95 145 153 155 150 100
v-3
Melting point
Concentration
0.87 1.03 1.20 1.00 0.99 0.89 1.41 1.07 1.07 0.97 1.04 1.13 1.02 1.02 0.98
(mW
62 63 60 65 60 63 55 60 63 61 61 63 64 64 60
Conductance A, (a-’ cm’mol-‘)
1095,s 823, s 1290,sh;1240,w;1225,m;1175,w;1150,w 1056, s; 1050, sh 775, s; 770,s 565,sh;556,s;535,m;513,m
1100, m; 1095,s 832, sh ; 825, s 1290, m; 1245, w; 1225, w 1055, s; 1040, m 785, s; 770,s 560, s; 547, m; 535, m; 520, s
s, strong; m, medium; w, weak; sh, shoulder.
995,s
995,s
v(W
v,(COC) v,(COQ v&W v,(W) v(W a.,+ G%)
‘The letters refer to the line intensities:
Tb
Frequencieti (cm - ‘) for the following species
compounds
L.a
Vibration
IFtdata of some representative
TABLE 2
1095,s 825, s 1295.sh;124O,m;1215,m;1165,w 1056, w; 1045,s 776, s; 770, sh 560, s; 5520, s; 540, s; 515,s
996s
El.
Kms [lo] 1182 1049 785 552; 522
b-0
1013, s 1093,s 822, s -
313
The IR spectrum of free tso contains one peak at 445 cm- ’ which is assigned to a 6 ring. In the complexes this band is split in three with intensities varying along the lanthanide series. According to dames and Morris [ll] these bands can be attributed to metal-ligand (M t O-L) interactions. The adduct peaks are also more intense than those assigned to the 6 ring of free tso. However, the bands in the 445-475 cm-l range can also be partially accounted for by ring deformations, if it is assumed that not all the tso has the same conformation. Tbe free ms ion, which has a C,, point group symmetry, can give rise to 11 experimental frequencies. Five of these belong to the symmetrical class A (polarized) and six to the degenerate class E (depolarized) which are all active in Raman and IR [lo]. The CH,SO,- group shows strong bands, which have been assigned [lo} and calculated [12-141 as antisymmetric and symmetric SO, stretching modes in the region between 1300and 1040cm- I. The coordination of the anion (monodentate or bidentate) distorts and reduces the C,, symmetry 1123.The large number of bands observed for the complexes in the region 13001040 cm-’ and also in the deformation region (about 550 cm-‘) (Table 2) are indicative of the presence of more than one type of anion in the lattice. The electronic f-f transition bands normally show weak perturbations due to complexation, but an increase in the intensity, shifts to the red region and splitting of some bands by the crystal field of the aquo ion are observed on complex formation. The spectrum of the Nd3 + ion is frequently used to verify the effect of the vicinity in hypersensitive and non-hypersensitive bands. The nephelauxetic parameter /? and the hypersensitivity of certain transitions have been correlated with the covalency. The spectra of the n~dymium compound recorded under various experimental conditions are depicted in Fig. 1. The value of the-neplrelauxetic parameter (/I = 0.991) was calculated from the room temperature spectrum using the transitions 4G5,2, 2G,,, c 4I9,2 and 2P1,2t 41,,2. The covalency [15] (b’12 = 0.667) and Sinha’s parameter [16] (6 = 0.86) were also calculated. These data are indicative of the lack of pa~icipation of the 4f orbitals in bonding. The number of main bands in the hypersensitive region of the spectrum at 77 K is greater than five and therefore cubic site symmetries are excluded. The absorption spectra of Nd(ms)3*3tso, Nd(ms)J+3H20 and Nd(ms), in methanolic solution are almost the same but differ markedly from that of the solid adduct. The measured oscillator strength [17] (P = 11.4 x low6 cm2 mol-’ 1) is greater than but of the same order of magnitude as those obtained from the salts in this solvent (8.46 x lo-$ and 9.09 x 10e6 cm2 mol- ll [l, 21). The emission spectra of the europium complex (Fig. 2) show one weak, but clearly observable, ‘D, -+ ‘FO transition. The stronger intensity of the electricdipole-allowed transitions with respect to the magnetic-dipole-allowed transitions suggests a low symmetry. However, the small number of intense bands and the particular structure of some transitions (e.g. 5D, 3 ‘F,) suggest that the actual coordination polyhedron may arise from a small distortion of a more symmetrical arrangement. Possible candidates for this pseudosymmetry, if the stoichiometry of the adducts is taken into account, include some of the trigonal point groups and D2d[18].
314
;t I’ t1 I I I \
428
430
434
h,nm
_._.-.-._,_.-.'\ , 570
6 580
Fig. 1. Absorption spectra of then~y~~ in methanolic solution.
I 590
adduct: -,
'. __---___ t 600
-____/--h,nm
atroomtemperature; ---, at77 K; -.-,
4. Comparison with tetramethylene sulphoxide The compounds were prepared using the same procedure and have the composition Ln(ms),*3L (L _=ligand). In both cases the sulphoxide oxygen is responsible for the bonding. The ms anions are coordinated and appear to act as bidentate for the tmso adducts, but other types of coordination are not excluded. All the complexes are non-electrolytes in methanolic solution (lo- 3 M). The visible spectra of the neodymium compounds present different shapes but have very similar values of 6, b1j2 and 6. In methanolic solutions the intensities of the hypersensitive transitions show a correlation with the basicity of the ligand, increasing in the order hydrated salt < anhydrous salt < tmso < tso < 2-picoline-N-oxide [4] Q hmpa [S]. The fluorescence spectrum of Eu(ms),*3tmso [3] shows a very weak line at 530 nm associated with the 5D, -+ ‘F, tr~sition which was assumed to be forbidden. The 5D, -+ ‘F, transition consists of three components, two of which are attributable to an E species. The region of ‘D, -+ ‘F, contains four intense peaks attributed to two E species (one electron-dipole-allowed and one magnetic-dipole-allowed transition) [183. A distorted DBhsite symmetry with a
315
100 -
go-
80 -
70 5 Do’
7
5 7 0,” F
F2
4
60 -
50 -
5
407 O,_,* F 4 30 -
Doh7F I
5
5 20
D* 0
7
F I
IO ~ -14
15
16
I7
18 14
15
16
I
5D*7F 0 0
17
I8
xlo3,,-l @)
Fig. 2. Emission
spectra of the europium
adduct at (a) 77 K and (b) room temperature.
t&zapped trigonal prism geometry was suggested, with the assumption that ma behaves as a bidentate ligand [3].
The authors are grateful to Financiadora de Estudos e Projetos and Funda@o de Amparo h Pesquisa do E&ado de S&o Paulo for financial support, and to Professor G. Vicentini for many helpful discussions and criticism. One of us (E.C.S.) (from Universidade Federal de Mato Grosso) is much indebted to Programa Institutional de CapacitaCBo de Docentes-Coordenadoria do Aperfeicoamento do Pessoal de Nivel Superior for a fellowship.
References
1 L. B. Zinner,An. Assoc. Bras. Quim., 30(1979) 27. 2
L. B. Zinner, An. Acad. Bras. Cieac., tiZ(1980) 715.
316
3 L. B. Zinner and G. Vicentini, J. Inorg. Nucl. Chem., 42(1980) 1349. 4 G. Vicentini, A. M. P. Felicissimo and L. B. Zinner, An. Acad. Bras. Ci&nc., 53(1981) 323. 5 A. M. P. Felicissimo, G. Vicentini and L. B. Zinner, An. Acad. Bras. Ci&nc., 54 (1982) 65. 6 M. A. P. Dankleff, R. Curci, J. 0. Edwards and H. Pyun, J. Am. Chem. Sot., 90 (1968) 3209. 7 S. J. Lyle and M. Md. Rahman, Talanta, 10 (1963) 1177. 8 W. J. Gear-y,Coord. Chem. Rev., 7(1971) 81. 9 Y.Hase and Y. Kawano, Spectrosc. Lett., 11(1978) 151. 10 H. Gerding and J. W. Maarsen, Reel. Trav. Chim. Pays-Bas, 77(1958) 374. 11 B. R. James and R. H. Morris, Spectrochim. Acta, Part A, 34 (1978) 577. 12 R. J. Capwell, K. H. Rhee and K. S. Seshadu, Spectrochim. Acta, Part A, 24 (1968) 955. 13 K. Fugimori, Bull. Chem. Sot. Jpn., 32(1959) 621. 14 W. K. Thompson, Spectrochim. Acta, Part A, 28(1972) 1479. 15 D. E. Henrie and G. R. Choppin, J. Chem. Phys., 49 (1968) 477. 16 S. P. Sinha, Spectrochim. Acta, 22 (1966) 57. 17 W. T. Carnall, P. R. Fields and B. G. Wyboume, J. Chem. Phys., 42 (1965) 3797. 18 J. H. Forsberg, Coord. Chem. Rev., IU(1973) 195.
Marls,
94 (1983) 309316
309
COMPLEXES OF LANTHANIDE METHANESULPHONATES WITH THIOXANE OXIDE : COMPARISON WITH TETRAMETHYLENE SULPHOXIDE*
L. B. ZINNER and E. CASTRO
DE SILVA
In&i&to de Quimica, Uniuersidade de SGo Pa&, (Brazil)
Caixu Postal 20.780.01498 Scio PauEo, Sk Paul0
(Received January 27,1983)
Summary Rare earth methanesulphonates (ms) react with thioxane oxide (tso) to give compounds with the composition Ln(ms&*3tso (Ln z La-Lu, Y). These compounds were isolated and their properties were studied. The molar conductance measurements are compatible with non-electrolytic behaviour. The vibrational spectra in the IR region indicate that tso coordination occurs through the sulphoxide group and that the ms ions are coordinated. X-ray powder patterns differentiate three types of isomorphous compounds: lanthanum to gadolinium; terbium and dysprosium; hohnium to lutetium and yttrium. The visible absorption spectrum of the solid neodymium compound suggests that the 4f orbitals are weakly involved in bonding and that the Nd3+ ion is not in a cubic site. The fluorescence spectrum of Eu(ms),*3tso is tentatively interpreted.
1. Introduction The methanesulphonate (ms) anion derived from the corresponding strong acid may act as a non-coordinating agent or as a monodentate, bidentate or tridentate ligand. To study its behaviour towards the tripositive lanthanides, the hydrated and anhydrous salts have been prepared [1, Z] and research involving these salts in relation to ligands containing oxygen as donor atom has been initiated. Complexes with tetramethylene sulphoxide (tmso) [3], 2-picolineN-oxide [4] and hexamethylphosphoramide (hmpa) [5] have been prepared and studied. Here we present the synthesis and characterization of the adducts between lanthanide methanesulphonates and thioxane oxide (tso). Some properties of the complexes are compared with those reported for the tmso compounds [3 1. *Paper presented at the Sixteenth Rare Earth Research Conference, Tallahassee, FL, U.S.A., April l&21,1983. 0
The Florida State University,
Elsevier Sequoia/Printed
in The Netherlands
310
2. Experimental
details
2.1. Preparation The anhydrous ms salts [2] were treated with an excess of tso (prepared from 2,4-thioxane (Aldrich) by oxidation with hydrogen peroxide solution [S]). The mixture was gently warmed and stirred with a glass rod. The viscous solution formed was treated with a large excess of anhydrous acetone to precipitate the adducts, which were filtered, washed with acetone and dried in uacuo over anhydrous calcium chloride. The compounds are hygroscopic, particularly those from gadolinium to lutetium and yttrium, and must be handled under anhydrous conditions. 2.2. Analysis and measurements The analytical data for the lanthanides were obtained by complexometric titration [7]. Carbon and hydrogen were determined by microanalytical procedures. Electrolytic conductance measurements were performed at 25.00 f0.02 “C using a bridge and cell (K, = 0.1070s cm-‘) obtained from Leeds and Northrup. X-ray powder patterns were obtained using a Norelco instrument and Cu Kct radiation. IR spectra were recorded on a Perkin-Elmer model 180 spectrophotometer. The absorption spectra of the neodymium adducts were recorded using a Cary 17 spectrophotometer. The emission spectra of the europium compounds were measured using a Zeiss ZFM-4 spectrofluorometer (excitation wavelength, 394 run). The refractive index of the methanolic solution was determined using a Bausch and Lomb Abbe-type refractometer.
3. Results and discussion The rare earth methanesulphonates Ln(ms), react with tso to give microcrystalline complexes of Ln(ms),*3tso stoichiometry. The complexes prepared, together with their analytical data and some physical properties, are listed in Table 1. The X-ray powder diffraction patterns are well resolved. The interplanar spacings and line intensities show that they are crystalline and reflect the presence of three isomorphous series: lanthanum to gadolinium compounds; holmium to lutetium and yttrium terbium and dysprosium compounds; compounds. The molar conductivities of solutions of the complexes (10V3 M in methanol) indicate non-electrolytic behaviour (Table l), implying that the ms anions are coordinated to the metal ions [S]. Some characteristic IR absorptions of the ligand bands are included in Table 2 and were assigned according to ref. 9. The coordination of the tso to the rare earth ions results in a red shift of the 1013 cm- ’ band which is assigned to v(S0). Shifts and/or splittings of the bands corresponding to both antisymmetric and symmetric C-O-C vibrations were also found. This suggests that the ethereal oxygen is also a ligation site in some of the complexes.
DY Ho Er Tm Yb Lu Y
La Ce Pr Nd Sm Eu Gd Tb
Ln
22.76 22.54 22.91 22.56 22.54 22.22 22.63 22.38 22.22 21.53 21.83 21.75 21.86 21.79 24.09
17.51 17.76 17.96 18.05 18.84 19.19 19.57 19.03 20.33 20.07 20.28 20.62 20.67 21.23 12.23
22.96 22.93 22.91 22.81 22.63 22.59 22.44 22.39 22.29 22.23 22.16 22.12 22.01 21.95 24.53
17.71 17.83 17.91 18.26 18.89 19.05 19.58 19.75 20.11 20.31 20.58 20.74 21.14 21.32 12.10
Experimental
Theoretical
Theoretical
Experimental
c
data for the lanthanides
Ln
(%)
melting point and conductance
Composition
Analytical,
TABLE 1 Ln
Experimental 4.45 4.55 4.44 4.46 4.50 4.29 4.27 4.57 4.86 4.82 4.65 4.33 4.25 4.40 5.04
Theoretical 4.24 4.23 4.23 4.21 4.17 4.17 4.14 4.13 4.12 4.10 4.09 4.08 4.06 4.05 4.53
H
185 175 170 165 155 150 145 135 125 95 145 153 155 150 100
v-3
Melting point
Concentration
0.87 1.03 1.20 1.00 0.99 0.89 1.41 1.07 1.07 0.97 1.04 1.13 1.02 1.02 0.98
(mW
62 63 60 65 60 63 55 60 63 61 61 63 64 64 60
Conductance A, (a-’ cm’mol-‘)
1095,s 823, s 1290,sh;1240,w;1225,m;1175,w;1150,w 1056, s; 1050, sh 775, s; 770,s 565,sh;556,s;535,m;513,m
1100, m; 1095,s 832, sh ; 825, s 1290, m; 1245, w; 1225, w 1055, s; 1040, m 785, s; 770,s 560, s; 547, m; 535, m; 520, s
s, strong; m, medium; w, weak; sh, shoulder.
995,s
995,s
v(W
v,(COC) v,(COQ v&W v,(W) v(W a.,+ G%)
‘The letters refer to the line intensities:
Tb
Frequencieti (cm - ‘) for the following species
compounds
L.a
Vibration
IFtdata of some representative
TABLE 2
1095,s 825, s 1295.sh;124O,m;1215,m;1165,w 1056, w; 1045,s 776, s; 770, sh 560, s; 5520, s; 540, s; 515,s
996s
El.
Kms [lo] 1182 1049 785 552; 522
b-0
1013, s 1093,s 822, s -
313
The IR spectrum of free tso contains one peak at 445 cm- ’ which is assigned to a 6 ring. In the complexes this band is split in three with intensities varying along the lanthanide series. According to dames and Morris [ll] these bands can be attributed to metal-ligand (M t O-L) interactions. The adduct peaks are also more intense than those assigned to the 6 ring of free tso. However, the bands in the 445-475 cm-l range can also be partially accounted for by ring deformations, if it is assumed that not all the tso has the same conformation. Tbe free ms ion, which has a C,, point group symmetry, can give rise to 11 experimental frequencies. Five of these belong to the symmetrical class A (polarized) and six to the degenerate class E (depolarized) which are all active in Raman and IR [lo]. The CH,SO,- group shows strong bands, which have been assigned [lo} and calculated [12-141 as antisymmetric and symmetric SO, stretching modes in the region between 1300and 1040cm- I. The coordination of the anion (monodentate or bidentate) distorts and reduces the C,, symmetry 1123.The large number of bands observed for the complexes in the region 13001040 cm-’ and also in the deformation region (about 550 cm-‘) (Table 2) are indicative of the presence of more than one type of anion in the lattice. The electronic f-f transition bands normally show weak perturbations due to complexation, but an increase in the intensity, shifts to the red region and splitting of some bands by the crystal field of the aquo ion are observed on complex formation. The spectrum of the Nd3 + ion is frequently used to verify the effect of the vicinity in hypersensitive and non-hypersensitive bands. The nephelauxetic parameter /? and the hypersensitivity of certain transitions have been correlated with the covalency. The spectra of the n~dymium compound recorded under various experimental conditions are depicted in Fig. 1. The value of the-neplrelauxetic parameter (/I = 0.991) was calculated from the room temperature spectrum using the transitions 4G5,2, 2G,,, c 4I9,2 and 2P1,2t 41,,2. The covalency [15] (b’12 = 0.667) and Sinha’s parameter [16] (6 = 0.86) were also calculated. These data are indicative of the lack of pa~icipation of the 4f orbitals in bonding. The number of main bands in the hypersensitive region of the spectrum at 77 K is greater than five and therefore cubic site symmetries are excluded. The absorption spectra of Nd(ms)3*3tso, Nd(ms)J+3H20 and Nd(ms), in methanolic solution are almost the same but differ markedly from that of the solid adduct. The measured oscillator strength [17] (P = 11.4 x low6 cm2 mol-’ 1) is greater than but of the same order of magnitude as those obtained from the salts in this solvent (8.46 x lo-$ and 9.09 x 10e6 cm2 mol- ll [l, 21). The emission spectra of the europium complex (Fig. 2) show one weak, but clearly observable, ‘D, -+ ‘FO transition. The stronger intensity of the electricdipole-allowed transitions with respect to the magnetic-dipole-allowed transitions suggests a low symmetry. However, the small number of intense bands and the particular structure of some transitions (e.g. 5D, 3 ‘F,) suggest that the actual coordination polyhedron may arise from a small distortion of a more symmetrical arrangement. Possible candidates for this pseudosymmetry, if the stoichiometry of the adducts is taken into account, include some of the trigonal point groups and D2d[18].
314
;t I’ t1 I I I \
428
430
434
h,nm
_._.-.-._,_.-.'\ , 570
6 580
Fig. 1. Absorption spectra of then~y~~ in methanolic solution.
I 590
adduct: -,
'. __---___ t 600
-____/--h,nm
atroomtemperature; ---, at77 K; -.-,
4. Comparison with tetramethylene sulphoxide The compounds were prepared using the same procedure and have the composition Ln(ms),*3L (L _=ligand). In both cases the sulphoxide oxygen is responsible for the bonding. The ms anions are coordinated and appear to act as bidentate for the tmso adducts, but other types of coordination are not excluded. All the complexes are non-electrolytes in methanolic solution (lo- 3 M). The visible spectra of the neodymium compounds present different shapes but have very similar values of 6, b1j2 and 6. In methanolic solutions the intensities of the hypersensitive transitions show a correlation with the basicity of the ligand, increasing in the order hydrated salt < anhydrous salt < tmso < tso < 2-picoline-N-oxide [4] Q hmpa [S]. The fluorescence spectrum of Eu(ms),*3tmso [3] shows a very weak line at 530 nm associated with the 5D, -+ ‘F, tr~sition which was assumed to be forbidden. The 5D, -+ ‘F, transition consists of three components, two of which are attributable to an E species. The region of ‘D, -+ ‘F, contains four intense peaks attributed to two E species (one electron-dipole-allowed and one magnetic-dipole-allowed transition) [183. A distorted DBhsite symmetry with a
315
100 -
go-
80 -
70 5 Do’
7
5 7 0,” F
F2
4
60 -
50 -
5
407 O,_,* F 4 30 -
Doh7F I
5
5 20
D* 0
7
F I
IO ~ -14
15
16
I7
18 14
15
16
I
5D*7F 0 0
17
I8
xlo3,,-l @)
Fig. 2. Emission
spectra of the europium
adduct at (a) 77 K and (b) room temperature.
t&zapped trigonal prism geometry was suggested, with the assumption that ma behaves as a bidentate ligand [3].
The authors are grateful to Financiadora de Estudos e Projetos and Funda@o de Amparo h Pesquisa do E&ado de S&o Paulo for financial support, and to Professor G. Vicentini for many helpful discussions and criticism. One of us (E.C.S.) (from Universidade Federal de Mato Grosso) is much indebted to Programa Institutional de CapacitaCBo de Docentes-Coordenadoria do Aperfeicoamento do Pessoal de Nivel Superior for a fellowship.
References
1 L. B. Zinner,An. Assoc. Bras. Quim., 30(1979) 27. 2
L. B. Zinner, An. Acad. Bras. Cieac., tiZ(1980) 715.
316
3 L. B. Zinner and G. Vicentini, J. Inorg. Nucl. Chem., 42(1980) 1349. 4 G. Vicentini, A. M. P. Felicissimo and L. B. Zinner, An. Acad. Bras. Ci&nc., 53(1981) 323. 5 A. M. P. Felicissimo, G. Vicentini and L. B. Zinner, An. Acad. Bras. Ci&nc., 54 (1982) 65. 6 M. A. P. Dankleff, R. Curci, J. 0. Edwards and H. Pyun, J. Am. Chem. Sot., 90 (1968) 3209. 7 S. J. Lyle and M. Md. Rahman, Talanta, 10 (1963) 1177. 8 W. J. Gear-y,Coord. Chem. Rev., 7(1971) 81. 9 Y.Hase and Y. Kawano, Spectrosc. Lett., 11(1978) 151. 10 H. Gerding and J. W. Maarsen, Reel. Trav. Chim. Pays-Bas, 77(1958) 374. 11 B. R. James and R. H. Morris, Spectrochim. Acta, Part A, 34 (1978) 577. 12 R. J. Capwell, K. H. Rhee and K. S. Seshadu, Spectrochim. Acta, Part A, 24 (1968) 955. 13 K. Fugimori, Bull. Chem. Sot. Jpn., 32(1959) 621. 14 W. K. Thompson, Spectrochim. Acta, Part A, 28(1972) 1479. 15 D. E. Henrie and G. R. Choppin, J. Chem. Phys., 49 (1968) 477. 16 S. P. Sinha, Spectrochim. Acta, 22 (1966) 57. 17 W. T. Carnall, P. R. Fields and B. G. Wyboume, J. Chem. Phys., 42 (1965) 3797. 18 J. H. Forsberg, Coord. Chem. Rev., IU(1973) 195.