- Email: [email protected]
Adducts of lanthanide trifluoromethanesulfonates and hexamethylphosphoramide (HMPA)
Notes ~knm
700
600
500
80 E"
193
670nm 114,900cm r) which could be related to the lower energy positive band in the CD spectra which itself is similar and at the same frequency to that of the single band of the mono complex.
AcknowledflementsiThis work was supported by the Servicio de Desarollo Cientifico, Adistico, y Cooperaciun International de la Universidad de Chile and the National Science Foundatior= Departmento de Quimi¢ a lnorganica y Analitica Facultad de Ciencias Quimicas Universidad de ChUe Santiago Chile
g....
S. B U N F,I.* C, IBARA M. RODRIGU EZ ,\ URBIN 4
C A BUNTON
Department of Chemistry University of Caqfornia Santa Barbara California 93106
REFERENCES
I
i
14
i
1~
i
10 -5
i
i
I~8 20 ~ cm-"
i
[~
22
Fig. 5 Absorption and CD spectra of: [Cu L-pen]2CI [Cu(L-pen)s] 2CI
*Author to whom correspondence should be addressed
l. C. J. Hawkins and C. L. Wong. Aust. J. Chem. 23, 2237(197()). 2. R. D. Gillard and S. H. Laurie, J. Chem. Soc. A. 59 ll970). 3. T. Yasui, J. Hidaka and Y. Shimura, J. Am. Chem S,w. 87, 2762 (1965). 4. S. Bunel, C. Ibarra, A. Urbina and C. A. Bunion, Inor~,. Nucl. Chem. Lett. 13, 259 ¢1977). 5. S. Bunel, C. lbarra, M. Rodriguez, A. Urbina and C A. Bunion. J. Inorg. Nucl. Chem., submitted. 6. H. Kinoshita and Y. Yoshino, Scientific Papers, Coll. Gen. Ed. University o[ Tokyo 23, 99 (1972); Chem. Abs., 81, 114013{1974). 7. C. J. Hawkins, Absolute Configuration of Metal Complexes, Chap. 5. Wiley-lnterscience, New York (1971),
J. inorq, nucl. Chem. Vol. 43, pp, 193-198 Pergamon Press Ild.. 1081. Printed in Great Britain
Adducts of lanthanide trifluoromethanesulfonates and hexamethylphosphoramide (HMPA) (Received 20 March 1980: received for publication 22 May 1980) Lanthanide complexes containing HMPA as ligand have been extensively studied by several authors. Emphasis has been given to perchlorates, due to the different compositions obtained. The first complex prepared was that of composition [I~n(NO~),dHMPAh] BPh4, by Pneumaticakis[1]. Adducts of lanthanide chlorides with general formula LnCI3.3HMPA have been described by Donoghue and Peters[2] and the structure of the praseodymium chloride complex determined by Radonovich and Glick[3]. Using different methods of preparation Donoghue et al.[4} and Giesbrecht and Zinner[5] independently obtained compounds with formula Ln(CIO4)3.6 HMPA. Durney and Marianelli[6] reported the preparation and characterization of complexes with composition [Ln(CIO4)2 (HMPA)4]CIO4. Scholer and Merbach[7] were able to synthesize both types of perchlorate adducts. The preparation of some lanthanide trifluoromethanesulfonate complexes, with composition Ln(GCSOo3.4HMPA by Thom[8]: of nitrate complexes with several compositions, by Sylvanovich and Madan[9] and by Sinha[10]; of some tetraphenylborate complexes by Melo and Serra[11] and Kuya et al.[12] and of bromide adducts, with general formula LnBr3.4HMPA, by Mikleev et al.[13] have been described. Analysis of the fluorescence spectra of several europium complexes were also studied[N, 15]. In this article the preparation of adducts with formulas LnfF3C-SO3)3.6HMPA (Ln : La-Nd, Eu) and Ln(F3CSO~h.4HMPA (Ln = Nd-Lu. Y) is described. The compounds I1NC Vol 4!. No [ M
were characterized by elemental analysis, X-ray powder patterns. electrolytic conductance data in acetonitrile and nitromethane, IR spectra, absorption spectra of neodymium and emission spectra of europium compounds.
EXPERIMENTAL The hydrated trifluoromethanesulfonates were prepared as recently described[16]. For the preparation of the adducts with six HMPA molecules, the hydrated salts were first heated at 200°C to eliminate the most part of hydration water, cooled and then reacted with an excess of HMPA; the mixture was gently warmed and treated with triethyl-orthoformate. The crystals were filtered, washed with small portions of triethyl-orthoformate and dried in vacuo, over anhydrous calcium chloride. Attempts to prepare compounds with six HMPA ligands of the heavy lathanides were unsuccessful. To obtain the compounds with four ligands, the hydrated salts were dissolved in an excess of HMPA at room temperature, after addition of triethyl-orthoformate, the crystals formed were filtered, washed with this solvent and dried as above. Analysis and measurements. These were performed a~ described in[16]. RESULTS
AND
DISCUSSION
Table 1 contains a summary of the analytical data and melling ranges. The complexes are soluble in acetonitrile, nitromethane,
194
Notes Table 1. Summary of analytical results and melting ranges
Analysis Lanthanide Compound
(%)
Carbon
Hydrogen
Melting
Theor.
Exp.
Theor.
Exp.
Theor.
Exp.
La(F3C-SO3)3.6HMPA Ce(F3C-SO3)3.6HMPA
8.36
8.50
28.19
28.38
6.55
8.43
8.35
28.18
28.16
6.55
6.37 6.61
Pr(F3C-SO3)3.6HMPA
8.47
8.56
28.16
27.97
6.54
6.43
284 - 289
Nd(F3C-SO3)3.6HMPA
8.65
8.63
28.11
28.12
6.53
6 70
288 -290
range,
°C
295 - 298 280 - 290
Eu(F3C-SO3)3.6HMPA
9.08
9.21
27.97
27.97
6.50
6 63
294 - 3 0 2
Nd(F3C-SO3)3.4HMPA
11.03
11.15
24.79
25.00
5.55
285 - 294
Sm(F3C-SO3)3.4BMPA
11.44
11.48
24.67
24.51
5.52
5 52 5 27
Eu(F3C-SO3)3.4HMPA
11.55
ll.61
24.64
25.00
5.51
579
2 9 2 - 296
Gd(F3C-SO3)3.4HMPA
ll.90
i1.86
24.54
24.60
5.49
289 - 294
Tb(F3C-SO3)3.4HMPA
12.01
12.04
24.51
24.47
5.49
5 62 5 60
DY(F3C-SO3)3.4HMPA
12.25
12.33
24.45
24.60
5.47
5 44
290 - 294
Ho(F3C-SO3)3.4HMPA
12.41
12.43
24.40
24.65
5.46
5 41
287 - 292
Er(F3C-SO3)3.4HMPA
12.56
12.81
24.35
24.44
5.45
Tm(F3C-SO3)3.4HMPA
12.67
13.05
24.33
24.50
5.44
5 23 5.69
2 9 1 - 295
Yb(F3C-SO3)3.4HMPA
12.94
13.03
24.25
24.44
5.43
5.59
293 - 296
Lu(F3C-SO3)3.4HMPA
13.07
13.18
24.22
24.09
5.42
5.38
2 9 8 - 3O2
Y(F3C-SO3)3.4HMPA
7.10
7.27
25.88
25.87
5.79
5.65
289 - 296
Table 2. Electrolytic conductance data in acetonitrile and nitromethane Nitromethane
Acetonitrile Compound
Conc.,mM
Am
Conc.,mM
Am
La(F3C-SO3)3.6HMPA
1.04
311
0.96
147
Ce(F3C-SO3)3.6HMPA
1.01
307
0.97
146
Pr(F3C-SO3)3.6HMPA
1.00
312
1.06
139
Nd(F3C-SO3)3.6HMPA
1.03
303
1.04
140
Eu(F3C-SO3)3.6HMPA
0.962
325
0.95
132
Nd(F3C-SO3)3.4HMPA
1.15
250
1.06
I01
Sm(F3C-SO3)3.4HMPA
0.98
240
1.18
I01
Eu(F3C-SO3)3.4HMPA
0.95
238
0.97
106
Gd(F3C-SO3)3.4HMPA
0.97
235
1.07
102
222
0.97
105
Tb(F3C-SO3)3.4HMPA
0.94
Dy(F3C-SO3)3.4HMPA
0.96
220
0.91
106
Ho(F3C-SO3) 3 4HMPA
1.06
216
0.95
108
Er(F3C-SO3) 3 4HMPA
0.94
229
1.00
ii0
Tm(F3C-S03) 3 4HMPA
0.94
228
0.98
109
¥ b ( F 3 C - S O 3 ) 3 4HMPA
0.98
237
0.98
113
Lu(F3C-S03) 3 4HMPA
0.94
249
0.93
117
Y(F3C-SO3) 3 4~MPA
0.98
215
1.04
106
Am = ~ - I
em 2 " mole-1.
294 - 297
293 - 297
292 - 296
4HMPA
Y(F3C-SO3)
1332s
1337s
1335s
1337s
s - strong,
4HMPA
Lu(F3C-S03)
v " very,
4HMPA
4HMPA
Tm(F3C-S03)
Yb(F3C-SO3)
1334s
1332s
4HMPA
4HMPA
Ho(F3C-SO3)
133Os
Dy(F3C-SO3).4HMPA
Er(F3C-SO3)
1330s
1330s
Eu(F3C-SO3),4HMPA
1332s
1330s
Sm(F3C-SO3).4HMPA
Tb(F3E-SO3).4HMPA
1328s
Nd(F3C-SO3).4HMPA
Gd(F3C-SO3).4HMPA
1272vs
m
1240m
1240m
1240m
1242m
1240m
1238m
1238m
1240m
1238m
1238m
1238m
1237m
-
-
-
w
~ A S . SO3
- medium,
1274s
1277s
1277s
1278s
1274s
1274s
1274s
1274s
1272s
1272s
1272s
1272s
1272vs
-
Eu(F3C-SO3).6HMPA
1277vs
Nd(F3C-SO3).6HMPA
1272vs
-
1272vs
Pr(F3C-SO3).6HMPA
-
-
Ce(F3C-SO3).6HMPA
La(F3C-SO3).6HMPA
HMPA
Compound
- weak,
1225sh
1225vw
1225vw
1225vw
1220vw
1220vw
1220vw
1222w
1220w
1220w
1220w
1220w
1222w
1220w
1222w
1220w
1222w
oh
llgOs
l190s
l190s
l190s
i188s
I185s
I188s
I188s
i187s
i188s
i187s
i187s
li90s
i187s
llgOs
llgOs
i198s
I144m
1140m
]140m
l]40m
i142m
l140m
i142m
1142m
l140m
i142s
1147s
i142s
l140s
i143s
i142m
l140m
I142m
- shoulder.
1212s
1214s
1217s
1215s
1212s
1210s
1210s
1210s
1210s
1210s
1210s
1208s
-
-
-
-
-
-
\>CF 3
*)
l]O7vs
ll07vs
lll0vs
ll05vs
ll02vs
llO0vs
flOOrs
1098vs
1095vs
1092vs
1094vs
1092vs
i092vs
1083vs
1087vs
1088vs
1092vs
1200s
~3PO
Table 3 1R da':a Icm
1032sh
1032sh
1037vw
1032vw
I032w
i032w
I034w
i032m
I032s
1032m
1030w
1032s
1030m
i032s
i032m
I032m
-
-
-
-
-
1030s
1030s
i032s
1030s
i027s
I027s
I027s
i027s
i022s
i024w
I024w
1021s
vS. ,qO~
995vs
995vs
lO00vs
990vs
995vs
992vs
995vs
995vs
992vs
992vs
995vs
992vs
995vs
99Ovs
99Ors
995vs
998vs
998vs
'oA~.pNC
758s
757s
760s
754s
757s
568w 568w 567w 570w 567w 570w
632s 640s 637s 638s
568w
637s 758s
637s
570w
637s
758s
637s
570w
637s 757s
757s
570w
567w
635s 757s
637s
570w
637s
759s
758s
567w
633s
758s
570w
570w
637m
760s
637s
570w
637s
760s
758s
570w
<5A ~ .SO % ~ C F ~
638s
760s
750s
~ $ PNC
512w
510w
512w
510w
510w
510w
512w
515w
512w
512w
512w
5LOw
518w
512w
516w
517w
517w
~S03 -
Z
196
Notes with data for perchlorates[4,5] for the hexakis adducts may be interpreted as non coordination of the anions, and the apparent coordination number six may be considered for the complex species. The conductance data in nitromethane is probably due to the existence of ion pairs. For the tetrakis compounds, IR and conductance data in nitromethane, may suggest the existence of one ionic and two bidentate trifluoromethanesulfonates; the coordination number eight may be given to the heavier lanthanides, because two bulky HMPA molecules were substituted in the coordination sphere by two bidentate anions. The behaviour in acetonitrile is due to interactions with the solvent, specially at lower concentrations. Figure l contains the absorption spectra of the neodymium compounds at room temperature and at 77K. The spectra at room temperature are quite similar, but not identical• The number of bands in the 77K spectra, may indicate that neodymium ions are not involved in cubic sites, but in the hexakis adduct the symmetry seems to be close to cubic. Figure 2 shows the absorption spectra of neodymium compounds in acetonitrile and nitromethane solutions. The spectra of the compound with four HMPA molecules, in both solvents are practically identical to that of the solid at room temperature, indicating the presence of the same species in solution. A few small differences between the spectra in solution and the solid hexakis complex, at room temperature, are observed, probably due to some solvent interaction, specially in acetonitrile. Nevertheless, all the spectra are considerably modified at low concentration (-0.003M). The nephelauxetic parameters, covalent factors and Sinha's parameters were determined as described in[20]. The values obtained (Table 4) are all indicative of very small participation of 4/orbitals in bonding. The oscillator strengths were determined at 25°C for -0.03M solutions in nitromethane and acetonitrile (Table 5). The intensities of the bands of the two adducts of
chloroform, methanol, ethanol and acetone• The adducts are not hygroscopic. According to X-ray powder patterns two series of isomorphous substances were obtained, corresponding to the adducts with six and four ligands. The conductance data in Table 2 show: a 1:3 electrolyte behaviour of the hexakis complexes and 1:2 for those with four ligands, in acetonitrile and a 1:2 electrolyte bebaviour for the adducts with six ligands and 1:1 for the tetrakis complexes, in nitromethane[17]. The IR data are presented in Table 3. The spectra do not show water bands. Two types of spectra were observed, corresponding to the two different series of adducts. The interpretation of the spectra of the compounds with four ligands is very difficult, because they present a great number of bands, due to non bonded and bonded trifluoromethanesulfonates. In all cases the situation is further complicated by the fact that previous studies[18,19] do not agree completely in the assignments concerning CF3 and SO3 vibrational modes, certainly due to the fact that the internal vibrations of these two pyramidal groups occur in the same regions and coupling between them is expected. Nevertheless, the number and position of the bands in the hexakis complexes are indicative that the anions are not coordinated. The attributions in Table 3 ate based in the assignments of Arduini et a/.[19]. Another aspect to be considered is that related to the P-O stretching mode: a shift by -20 cm t has been observed in several HMPA complexes. In our case a very strong band is observed in the -ll00cm-~ region in all complexes prepared, which may be attributed to uPO. Unusual shifts of this mode were also observed by Melo and Serra[ll] and Kuya et a/.[12] in tetraphenylborate complexes. The uPO and uPN shifts are indicative of coordination through the oxygen. IR and conductance data in acetonitrile, compared
:
!ii
A'I l:i
i:i
ii
r
'
°.
i
::i
t
i:.!
"
\ I ".
V\ /f
...........
..
i
.... . . . . . . . °
/ i "
i
,'\ -.
.
\'-:;! \ I
v
I
/ !
I
.
\
\
",~ -
.,u /
/ n
/,",
,-~
1
Cv..
..',/ "--.~.j
"'....."
',. _/',,l ~\
'l\
,
:/7
~.
\ ".
j
:
i • i
\/~"
i
/
i
'..
i_,*,..
i"
V
,,
i
!
\! i
~- i \"
!
"
..
: , ,!' ,.. \ .....\ /'#
'',~,.
I"
~,,
"
~
!
" 428
i =.1
j
.
"'~-'~-_
.'"'i, ! ""
\" ~ ." '- •
\-. .,,..
/
!
,,
4~0
432 ~,nm
....,
'::-
\
\'
"..
,,,/ x
5~5
570
5~5
5~o
5~
5~o
5~
6~o
Fig. 1. Absorption spectra of neodymium compounds: Nd(FsC-SO3)~.4HMPA at room temperature (dashed line); at 77K (dotted line). Nd(F3C-SO3)3.6HMPA at room temperature (solid line); at 77K (dashed-dotted line).
6~ ~,o~
Notes
197
? I.(:~
0.9
i
"
:It
08-
i 07
\~
o6~
: i!
,it
Ji i
', \'~.
05 ~
•
- iAi
~ \i'
.
', \i'.
.: il
4
- !I
', Vi... ..... !i
",
.. '/
E,,.."
\~ \~
\
..
z t//~ {'.. ".. i, ~~ ~,~" " " ' " ,/,,, c... ...": <.0,... \,,, ",. ,' / ", ",,:..... , I
O5-
02
-J
I
oo
:.//
~
5;5
~ .,.__7._-
/
5-}o
/
I
~
/
5-;5
~o
¢ ~
~ \x,,~ it,,
59o
~5
. . . .
-
595
6oo
d)5 x,o~,
Fig. 2. Absorption spectra of neodymium compounds in solution: Nd(F3C-SO3h'4HMPA in nitromethane, absolute range, A.R. = 1 (dashed line); acetonitrile, A.R. = 0.5 (dotted line). Nd(F3C-SO3h.6HMPA in nitromethane, A.R. = 0.5 (solid line); in acetonitrile, A.R. = 0.5 (dashed-dotted line).
Table 4. Spectroscopic data of the compounds of formulas Nd(F~C-SO3h.6HMPA and Nd(F~C-SO03.4HMPA
Transition
Spectroscopic
Nd(F3C-SO3)3.6HMPA
Nd(F3C-SO3)3.4HMPA
data
%, nm
?
429,0
~, cm -I
419/2 ~ 2PI/2
B 419/2 ~ 4G5/2,2G7/2
23,310 -
%. nm
0.9933
579.7
v, cm -i
579.7
17.250
17.250
0.9954
0.9954
0.9954
0.9944
b I/2
0.048
0.053
6
0.46
0.56
Table 5, Oscillator strengths (P) in acetonitrile and nitromethane
Compound
Nd(F3C-SO3)3,6HMPA
Nd(F3C-SO3)3.4BMPA
Solvent
Conc.,M
n
P x 106
acetonitrile
0.03055
1.3449
9.07
nitromethane
0.02640
1.3858
8.18
acetonitrile
0.03675
1.3502
9.22
nitromethane
0.03648
1.3854
7.57
198
Notes
5D~-
5D 6- ,.-rFI
L
5D--~.,..7 E
..J 5~o
5~5
J 610
i
6'2§ ~,om
I
580
i
595
i
610
1
625 ~,nrn
Fig. 3. Emission spectra of europium compounds, at 77K: a-Eu (F3C-SO~)3'6HMPA; b-Eu(F3C-SO3)3.4FIMPA. neodymium are very close in acetonitrile. In all cases the spectra are very similar and the intersities comparable to that of water solution [21 ]. Figure 3 contains the emission spectra of the europium adducts. The spectrum of the compound with six HMPA (a) with one band 5Do~7F,,, two peaks 5Do~TFi and two (or three) peaks 5D,,-TF2 was interpreted as due to a C4~. site symmetry[22], consistent with a distorted octahedral geometry. Considering the intensity of the 5D,,-7F~ compared with 5D,, 7F2 transition we may infer that the specie is nearly centrosymmetric. The spectrum of the tetrakis complex (b) contains one band at 583.4 nm (17,140cm -~) probably due to a 5D~--*TFj transition. The number of bands due to 519,,~7Ft and 5Do~7F2 transitions was interpreted as a D2d microsymmetry around Eu 3+, consistent with a Eu(0)8 chromophore[22].
Acknowledgement--The authors are much indebted to Mr Paulo E. Mori for the X-ray powder patterns. Instituto de Qufmica Universidade de S(to Paulo Caixa Postal: 20.780 S~o Paulo Brazil
L.B. ZINNER G. VICENTINI
REFERENCES
1. G. A. Pneumaticakis, Chem. Indian (London), 26, 882 (1%8). 2. J. T. Donoghue and D. A. Peters. J. Inorg. NucL Chem. 31, 467 (1%9). 3. L. J. Radonovich, and M. D. Glick. J. Inorg. Nucl. Chem. 35, 2745 (1973). 4. J. T. Donoghue, E. Fernandez, J. A. McMillan and D. A. Peters. J. Inorg. Nucl. Chem. 31, 1431 (1%9).
5. E. Giesbrecht and L. B. Zinner. lnorg. NucL Chem. Lett. 5, 575 (1%9). 6. M. T. Durney and R. S. Marianelli. lnorg. Nucl. Chem. Lett. 6, 895 (1970). 7. R. P. Scholer and A. E. Merbach, lnorg. Chim. Acta 15, 15 (1975). 8. K. F. Thorn. U.S. Pat. 3, 7%, 738: Apud Chem. Abstr. 81, 13114n (1974). 9. J. A. Sylvanovich Jr. and S. K. Madan. J. lnorg. NucL Chem. M, 1675 (1972). 10. S. P. Sinha. Z. Anorg. Allg. Chem. 434, 227 (1977). 11. S. M. Melo and O. A. Serra. Proc. 12th Rare-Earth Research Conf. 180 (1976). 12. M. K. Kuya, S. M. Melo and O. A. Serra. An. Acad. brasil. Ci~nc. 51,239 (1979). 13. N. B. Mikheev, A. N. Kamenskaya, N. A. Konovalova, T. A. Bidakova and L. M. Mikheeva, Zh. Neorg. Khim. 22, 3243 (1977); Apud. Chem. Abstr. 88, 57755w (1978). 14. S. P. Sinha. lnorg. Chim. Acta 28, 145 (1978). 15. S. P. Sinha, G. Vicentini, L. B. Zinner and A. Bartecki. 14th Rare-Earth Research Conf. (1979). 16. G. Vicentini and L. B. Zinner. J. lnorg. NucL Chem. (in press). 17. S. J. Lyle and M. Md Rahman Talanta, 10, 1177 (1%3). 18. M. G. Miles, G. Doyle, R. P. Cooney and R. S. Tobias. Spectrochim. Acta 25A, 1515 (1%9). 19. A. L. Arduini, M. Garnett, R. C. Thompson and T. C. T. Wong. Can. J. Chem. 53, 3812 (1975). 20. G. Vicentini, L. B. Zinner, A. M. P. Felicissimo and K. Zinner. J. 1norg. Nucl. Chem. 41, 1611 (1979). 21. D. C. Stewart. Argonne National Laboratory Rep. ANL 4812, (1952). 22. J. H. Forsberg. Coord. Chem. Rev. 10, 195 (1973).
700
600
500
80 E"
193
670nm 114,900cm r) which could be related to the lower energy positive band in the CD spectra which itself is similar and at the same frequency to that of the single band of the mono complex.
AcknowledflementsiThis work was supported by the Servicio de Desarollo Cientifico, Adistico, y Cooperaciun International de la Universidad de Chile and the National Science Foundatior= Departmento de Quimi¢ a lnorganica y Analitica Facultad de Ciencias Quimicas Universidad de ChUe Santiago Chile
g....
S. B U N F,I.* C, IBARA M. RODRIGU EZ ,\ URBIN 4
C A BUNTON
Department of Chemistry University of Caqfornia Santa Barbara California 93106
REFERENCES
I
i
14
i
1~
i
10 -5
i
i
I~8 20 ~ cm-"
i
[~
22
Fig. 5 Absorption and CD spectra of: [Cu L-pen]2CI [Cu(L-pen)s] 2CI
*Author to whom correspondence should be addressed
l. C. J. Hawkins and C. L. Wong. Aust. J. Chem. 23, 2237(197()). 2. R. D. Gillard and S. H. Laurie, J. Chem. Soc. A. 59 ll970). 3. T. Yasui, J. Hidaka and Y. Shimura, J. Am. Chem S,w. 87, 2762 (1965). 4. S. Bunel, C. Ibarra, A. Urbina and C. A. Bunion, Inor~,. Nucl. Chem. Lett. 13, 259 ¢1977). 5. S. Bunel, C. lbarra, M. Rodriguez, A. Urbina and C A. Bunion. J. Inorg. Nucl. Chem., submitted. 6. H. Kinoshita and Y. Yoshino, Scientific Papers, Coll. Gen. Ed. University o[ Tokyo 23, 99 (1972); Chem. Abs., 81, 114013{1974). 7. C. J. Hawkins, Absolute Configuration of Metal Complexes, Chap. 5. Wiley-lnterscience, New York (1971),
J. inorq, nucl. Chem. Vol. 43, pp, 193-198 Pergamon Press Ild.. 1081. Printed in Great Britain
Adducts of lanthanide trifluoromethanesulfonates and hexamethylphosphoramide (HMPA) (Received 20 March 1980: received for publication 22 May 1980) Lanthanide complexes containing HMPA as ligand have been extensively studied by several authors. Emphasis has been given to perchlorates, due to the different compositions obtained. The first complex prepared was that of composition [I~n(NO~),dHMPAh] BPh4, by Pneumaticakis[1]. Adducts of lanthanide chlorides with general formula LnCI3.3HMPA have been described by Donoghue and Peters[2] and the structure of the praseodymium chloride complex determined by Radonovich and Glick[3]. Using different methods of preparation Donoghue et al.[4} and Giesbrecht and Zinner[5] independently obtained compounds with formula Ln(CIO4)3.6 HMPA. Durney and Marianelli[6] reported the preparation and characterization of complexes with composition [Ln(CIO4)2 (HMPA)4]CIO4. Scholer and Merbach[7] were able to synthesize both types of perchlorate adducts. The preparation of some lanthanide trifluoromethanesulfonate complexes, with composition Ln(GCSOo3.4HMPA by Thom[8]: of nitrate complexes with several compositions, by Sylvanovich and Madan[9] and by Sinha[10]; of some tetraphenylborate complexes by Melo and Serra[11] and Kuya et al.[12] and of bromide adducts, with general formula LnBr3.4HMPA, by Mikleev et al.[13] have been described. Analysis of the fluorescence spectra of several europium complexes were also studied[N, 15]. In this article the preparation of adducts with formulas LnfF3C-SO3)3.6HMPA (Ln : La-Nd, Eu) and Ln(F3CSO~h.4HMPA (Ln = Nd-Lu. Y) is described. The compounds I1NC Vol 4!. No [ M
were characterized by elemental analysis, X-ray powder patterns. electrolytic conductance data in acetonitrile and nitromethane, IR spectra, absorption spectra of neodymium and emission spectra of europium compounds.
EXPERIMENTAL The hydrated trifluoromethanesulfonates were prepared as recently described[16]. For the preparation of the adducts with six HMPA molecules, the hydrated salts were first heated at 200°C to eliminate the most part of hydration water, cooled and then reacted with an excess of HMPA; the mixture was gently warmed and treated with triethyl-orthoformate. The crystals were filtered, washed with small portions of triethyl-orthoformate and dried in vacuo, over anhydrous calcium chloride. Attempts to prepare compounds with six HMPA ligands of the heavy lathanides were unsuccessful. To obtain the compounds with four ligands, the hydrated salts were dissolved in an excess of HMPA at room temperature, after addition of triethyl-orthoformate, the crystals formed were filtered, washed with this solvent and dried as above. Analysis and measurements. These were performed a~ described in[16]. RESULTS
AND
DISCUSSION
Table 1 contains a summary of the analytical data and melling ranges. The complexes are soluble in acetonitrile, nitromethane,
194
Notes Table 1. Summary of analytical results and melting ranges
Analysis Lanthanide Compound
(%)
Carbon
Hydrogen
Melting
Theor.
Exp.
Theor.
Exp.
Theor.
Exp.
La(F3C-SO3)3.6HMPA Ce(F3C-SO3)3.6HMPA
8.36
8.50
28.19
28.38
6.55
8.43
8.35
28.18
28.16
6.55
6.37 6.61
Pr(F3C-SO3)3.6HMPA
8.47
8.56
28.16
27.97
6.54
6.43
284 - 289
Nd(F3C-SO3)3.6HMPA
8.65
8.63
28.11
28.12
6.53
6 70
288 -290
range,
°C
295 - 298 280 - 290
Eu(F3C-SO3)3.6HMPA
9.08
9.21
27.97
27.97
6.50
6 63
294 - 3 0 2
Nd(F3C-SO3)3.4HMPA
11.03
11.15
24.79
25.00
5.55
285 - 294
Sm(F3C-SO3)3.4BMPA
11.44
11.48
24.67
24.51
5.52
5 52 5 27
Eu(F3C-SO3)3.4HMPA
11.55
ll.61
24.64
25.00
5.51
579
2 9 2 - 296
Gd(F3C-SO3)3.4HMPA
ll.90
i1.86
24.54
24.60
5.49
289 - 294
Tb(F3C-SO3)3.4HMPA
12.01
12.04
24.51
24.47
5.49
5 62 5 60
DY(F3C-SO3)3.4HMPA
12.25
12.33
24.45
24.60
5.47
5 44
290 - 294
Ho(F3C-SO3)3.4HMPA
12.41
12.43
24.40
24.65
5.46
5 41
287 - 292
Er(F3C-SO3)3.4HMPA
12.56
12.81
24.35
24.44
5.45
Tm(F3C-SO3)3.4HMPA
12.67
13.05
24.33
24.50
5.44
5 23 5.69
2 9 1 - 295
Yb(F3C-SO3)3.4HMPA
12.94
13.03
24.25
24.44
5.43
5.59
293 - 296
Lu(F3C-SO3)3.4HMPA
13.07
13.18
24.22
24.09
5.42
5.38
2 9 8 - 3O2
Y(F3C-SO3)3.4HMPA
7.10
7.27
25.88
25.87
5.79
5.65
289 - 296
Table 2. Electrolytic conductance data in acetonitrile and nitromethane Nitromethane
Acetonitrile Compound
Conc.,mM
Am
Conc.,mM
Am
La(F3C-SO3)3.6HMPA
1.04
311
0.96
147
Ce(F3C-SO3)3.6HMPA
1.01
307
0.97
146
Pr(F3C-SO3)3.6HMPA
1.00
312
1.06
139
Nd(F3C-SO3)3.6HMPA
1.03
303
1.04
140
Eu(F3C-SO3)3.6HMPA
0.962
325
0.95
132
Nd(F3C-SO3)3.4HMPA
1.15
250
1.06
I01
Sm(F3C-SO3)3.4HMPA
0.98
240
1.18
I01
Eu(F3C-SO3)3.4HMPA
0.95
238
0.97
106
Gd(F3C-SO3)3.4HMPA
0.97
235
1.07
102
222
0.97
105
Tb(F3C-SO3)3.4HMPA
0.94
Dy(F3C-SO3)3.4HMPA
0.96
220
0.91
106
Ho(F3C-SO3) 3 4HMPA
1.06
216
0.95
108
Er(F3C-SO3) 3 4HMPA
0.94
229
1.00
ii0
Tm(F3C-S03) 3 4HMPA
0.94
228
0.98
109
¥ b ( F 3 C - S O 3 ) 3 4HMPA
0.98
237
0.98
113
Lu(F3C-S03) 3 4HMPA
0.94
249
0.93
117
Y(F3C-SO3) 3 4~MPA
0.98
215
1.04
106
Am = ~ - I
em 2 " mole-1.
294 - 297
293 - 297
292 - 296
4HMPA
Y(F3C-SO3)
1332s
1337s
1335s
1337s
s - strong,
4HMPA
Lu(F3C-S03)
v " very,
4HMPA
4HMPA
Tm(F3C-S03)
Yb(F3C-SO3)
1334s
1332s
4HMPA
4HMPA
Ho(F3C-SO3)
133Os
Dy(F3C-SO3).4HMPA
Er(F3C-SO3)
1330s
1330s
Eu(F3C-SO3),4HMPA
1332s
1330s
Sm(F3C-SO3).4HMPA
Tb(F3E-SO3).4HMPA
1328s
Nd(F3C-SO3).4HMPA
Gd(F3C-SO3).4HMPA
1272vs
m
1240m
1240m
1240m
1242m
1240m
1238m
1238m
1240m
1238m
1238m
1238m
1237m
-
-
-
w
~ A S . SO3
- medium,
1274s
1277s
1277s
1278s
1274s
1274s
1274s
1274s
1272s
1272s
1272s
1272s
1272vs
-
Eu(F3C-SO3).6HMPA
1277vs
Nd(F3C-SO3).6HMPA
1272vs
-
1272vs
Pr(F3C-SO3).6HMPA
-
-
Ce(F3C-SO3).6HMPA
La(F3C-SO3).6HMPA
HMPA
Compound
- weak,
1225sh
1225vw
1225vw
1225vw
1220vw
1220vw
1220vw
1222w
1220w
1220w
1220w
1220w
1222w
1220w
1222w
1220w
1222w
oh
llgOs
l190s
l190s
l190s
i188s
I185s
I188s
I188s
i187s
i188s
i187s
i187s
li90s
i187s
llgOs
llgOs
i198s
I144m
1140m
]140m
l]40m
i142m
l140m
i142m
1142m
l140m
i142s
1147s
i142s
l140s
i143s
i142m
l140m
I142m
- shoulder.
1212s
1214s
1217s
1215s
1212s
1210s
1210s
1210s
1210s
1210s
1210s
1208s
-
-
-
-
-
-
\>CF 3
*)
l]O7vs
ll07vs
lll0vs
ll05vs
ll02vs
llO0vs
flOOrs
1098vs
1095vs
1092vs
1094vs
1092vs
i092vs
1083vs
1087vs
1088vs
1092vs
1200s
~3PO
Table 3 1R da':a Icm
1032sh
1032sh
1037vw
1032vw
I032w
i032w
I034w
i032m
I032s
1032m
1030w
1032s
1030m
i032s
i032m
I032m
-
-
-
-
-
1030s
1030s
i032s
1030s
i027s
I027s
I027s
i027s
i022s
i024w
I024w
1021s
vS. ,qO~
995vs
995vs
lO00vs
990vs
995vs
992vs
995vs
995vs
992vs
992vs
995vs
992vs
995vs
99Ovs
99Ors
995vs
998vs
998vs
'oA~.pNC
758s
757s
760s
754s
757s
568w 568w 567w 570w 567w 570w
632s 640s 637s 638s
568w
637s 758s
637s
570w
637s
758s
637s
570w
637s 757s
757s
570w
567w
635s 757s
637s
570w
637s
759s
758s
567w
633s
758s
570w
570w
637m
760s
637s
570w
637s
760s
758s
570w
<5A ~ .SO % ~ C F ~
638s
760s
750s
~ $ PNC
512w
510w
512w
510w
510w
510w
512w
515w
512w
512w
512w
5LOw
518w
512w
516w
517w
517w
~S03 -
Z
196
Notes with data for perchlorates[4,5] for the hexakis adducts may be interpreted as non coordination of the anions, and the apparent coordination number six may be considered for the complex species. The conductance data in nitromethane is probably due to the existence of ion pairs. For the tetrakis compounds, IR and conductance data in nitromethane, may suggest the existence of one ionic and two bidentate trifluoromethanesulfonates; the coordination number eight may be given to the heavier lanthanides, because two bulky HMPA molecules were substituted in the coordination sphere by two bidentate anions. The behaviour in acetonitrile is due to interactions with the solvent, specially at lower concentrations. Figure l contains the absorption spectra of the neodymium compounds at room temperature and at 77K. The spectra at room temperature are quite similar, but not identical• The number of bands in the 77K spectra, may indicate that neodymium ions are not involved in cubic sites, but in the hexakis adduct the symmetry seems to be close to cubic. Figure 2 shows the absorption spectra of neodymium compounds in acetonitrile and nitromethane solutions. The spectra of the compound with four HMPA molecules, in both solvents are practically identical to that of the solid at room temperature, indicating the presence of the same species in solution. A few small differences between the spectra in solution and the solid hexakis complex, at room temperature, are observed, probably due to some solvent interaction, specially in acetonitrile. Nevertheless, all the spectra are considerably modified at low concentration (-0.003M). The nephelauxetic parameters, covalent factors and Sinha's parameters were determined as described in[20]. The values obtained (Table 4) are all indicative of very small participation of 4/orbitals in bonding. The oscillator strengths were determined at 25°C for -0.03M solutions in nitromethane and acetonitrile (Table 5). The intensities of the bands of the two adducts of
chloroform, methanol, ethanol and acetone• The adducts are not hygroscopic. According to X-ray powder patterns two series of isomorphous substances were obtained, corresponding to the adducts with six and four ligands. The conductance data in Table 2 show: a 1:3 electrolyte behaviour of the hexakis complexes and 1:2 for those with four ligands, in acetonitrile and a 1:2 electrolyte bebaviour for the adducts with six ligands and 1:1 for the tetrakis complexes, in nitromethane[17]. The IR data are presented in Table 3. The spectra do not show water bands. Two types of spectra were observed, corresponding to the two different series of adducts. The interpretation of the spectra of the compounds with four ligands is very difficult, because they present a great number of bands, due to non bonded and bonded trifluoromethanesulfonates. In all cases the situation is further complicated by the fact that previous studies[18,19] do not agree completely in the assignments concerning CF3 and SO3 vibrational modes, certainly due to the fact that the internal vibrations of these two pyramidal groups occur in the same regions and coupling between them is expected. Nevertheless, the number and position of the bands in the hexakis complexes are indicative that the anions are not coordinated. The attributions in Table 3 ate based in the assignments of Arduini et a/.[19]. Another aspect to be considered is that related to the P-O stretching mode: a shift by -20 cm t has been observed in several HMPA complexes. In our case a very strong band is observed in the -ll00cm-~ region in all complexes prepared, which may be attributed to uPO. Unusual shifts of this mode were also observed by Melo and Serra[ll] and Kuya et a/.[12] in tetraphenylborate complexes. The uPO and uPN shifts are indicative of coordination through the oxygen. IR and conductance data in acetonitrile, compared
:
!ii
A'I l:i
i:i
ii
r
'
°.
i
::i
t
i:.!
"
\ I ".
V\ /f
...........
..
i
.... . . . . . . . °
/ i "
i
,'\ -.
.
\'-:;! \ I
v
I
/ !
I
.
\
\
",~ -
.,u /
/ n
/,",
,-~
1
Cv..
..',/ "--.~.j
"'....."
',. _/',,l ~\
'l\
,
:/7
~.
\ ".
j
:
i • i
\/~"
i
/
i
'..
i_,*,..
i"
V
,,
i
!
\! i
~- i \"
!
"
..
: , ,!' ,.. \ .....\ /'#
'',~,.
I"
~,,
"
~
!
" 428
i =.1
j
.
"'~-'~-_
.'"'i, ! ""
\" ~ ." '- •
\-. .,,..
/
!
,,
4~0
432 ~,nm
....,
'::-
\
\'
"..
,,,/ x
5~5
570
5~5
5~o
5~
5~o
5~
6~o
Fig. 1. Absorption spectra of neodymium compounds: Nd(FsC-SO3)~.4HMPA at room temperature (dashed line); at 77K (dotted line). Nd(F3C-SO3)3.6HMPA at room temperature (solid line); at 77K (dashed-dotted line).
6~ ~,o~
Notes
197
? I.(:~
0.9
i
"
:It
08-
i 07
\~
o6~
: i!
,it
Ji i
', \'~.
05 ~
•
- iAi
~ \i'
.
', \i'.
.: il
4
- !I
', Vi... ..... !i
",
.. '/
E,,.."
\~ \~
\
..
z t//~ {'.. ".. i, ~~ ~,~" " " ' " ,/,,, c... ...": <.0,... \,,, ",. ,' / ", ",,:..... , I
O5-
02
-J
I
oo
:.//
~
5;5
~ .,.__7._-
/
5-}o
/
I
~
/
5-;5
~o
¢ ~
~ \x,,~ it,,
59o
~5
. . . .
-
595
6oo
d)5 x,o~,
Fig. 2. Absorption spectra of neodymium compounds in solution: Nd(F3C-SO3h'4HMPA in nitromethane, absolute range, A.R. = 1 (dashed line); acetonitrile, A.R. = 0.5 (dotted line). Nd(F3C-SO3h.6HMPA in nitromethane, A.R. = 0.5 (solid line); in acetonitrile, A.R. = 0.5 (dashed-dotted line).
Table 4. Spectroscopic data of the compounds of formulas Nd(F~C-SO3h.6HMPA and Nd(F~C-SO03.4HMPA
Transition
Spectroscopic
Nd(F3C-SO3)3.6HMPA
Nd(F3C-SO3)3.4HMPA
data
%, nm
?
429,0
~, cm -I
419/2 ~ 2PI/2
B 419/2 ~ 4G5/2,2G7/2
23,310 -
%. nm
0.9933
579.7
v, cm -i
579.7
17.250
17.250
0.9954
0.9954
0.9954
0.9944
b I/2
0.048
0.053
6
0.46
0.56
Table 5, Oscillator strengths (P) in acetonitrile and nitromethane
Compound
Nd(F3C-SO3)3,6HMPA
Nd(F3C-SO3)3.4BMPA
Solvent
Conc.,M
n
P x 106
acetonitrile
0.03055
1.3449
9.07
nitromethane
0.02640
1.3858
8.18
acetonitrile
0.03675
1.3502
9.22
nitromethane
0.03648
1.3854
7.57
198
Notes
5D~-
5D 6- ,.-rFI
L
5D--~.,..7 E
..J 5~o
5~5
J 610
i
6'2§ ~,om
I
580
i
595
i
610
1
625 ~,nrn
Fig. 3. Emission spectra of europium compounds, at 77K: a-Eu (F3C-SO~)3'6HMPA; b-Eu(F3C-SO3)3.4FIMPA. neodymium are very close in acetonitrile. In all cases the spectra are very similar and the intersities comparable to that of water solution [21 ]. Figure 3 contains the emission spectra of the europium adducts. The spectrum of the compound with six HMPA (a) with one band 5Do~7F,,, two peaks 5Do~TFi and two (or three) peaks 5D,,-TF2 was interpreted as due to a C4~. site symmetry[22], consistent with a distorted octahedral geometry. Considering the intensity of the 5D,,-7F~ compared with 5D,, 7F2 transition we may infer that the specie is nearly centrosymmetric. The spectrum of the tetrakis complex (b) contains one band at 583.4 nm (17,140cm -~) probably due to a 5D~--*TFj transition. The number of bands due to 519,,~7Ft and 5Do~7F2 transitions was interpreted as a D2d microsymmetry around Eu 3+, consistent with a Eu(0)8 chromophore[22].
Acknowledgement--The authors are much indebted to Mr Paulo E. Mori for the X-ray powder patterns. Instituto de Qufmica Universidade de S(to Paulo Caixa Postal: 20.780 S~o Paulo Brazil
L.B. ZINNER G. VICENTINI
REFERENCES
1. G. A. Pneumaticakis, Chem. Indian (London), 26, 882 (1%8). 2. J. T. Donoghue and D. A. Peters. J. Inorg. NucL Chem. 31, 467 (1%9). 3. L. J. Radonovich, and M. D. Glick. J. Inorg. Nucl. Chem. 35, 2745 (1973). 4. J. T. Donoghue, E. Fernandez, J. A. McMillan and D. A. Peters. J. Inorg. Nucl. Chem. 31, 1431 (1%9).
5. E. Giesbrecht and L. B. Zinner. lnorg. NucL Chem. Lett. 5, 575 (1%9). 6. M. T. Durney and R. S. Marianelli. lnorg. Nucl. Chem. Lett. 6, 895 (1970). 7. R. P. Scholer and A. E. Merbach, lnorg. Chim. Acta 15, 15 (1975). 8. K. F. Thorn. U.S. Pat. 3, 7%, 738: Apud Chem. Abstr. 81, 13114n (1974). 9. J. A. Sylvanovich Jr. and S. K. Madan. J. lnorg. NucL Chem. M, 1675 (1972). 10. S. P. Sinha. Z. Anorg. Allg. Chem. 434, 227 (1977). 11. S. M. Melo and O. A. Serra. Proc. 12th Rare-Earth Research Conf. 180 (1976). 12. M. K. Kuya, S. M. Melo and O. A. Serra. An. Acad. brasil. Ci~nc. 51,239 (1979). 13. N. B. Mikheev, A. N. Kamenskaya, N. A. Konovalova, T. A. Bidakova and L. M. Mikheeva, Zh. Neorg. Khim. 22, 3243 (1977); Apud. Chem. Abstr. 88, 57755w (1978). 14. S. P. Sinha. lnorg. Chim. Acta 28, 145 (1978). 15. S. P. Sinha, G. Vicentini, L. B. Zinner and A. Bartecki. 14th Rare-Earth Research Conf. (1979). 16. G. Vicentini and L. B. Zinner. J. lnorg. NucL Chem. (in press). 17. S. J. Lyle and M. Md Rahman Talanta, 10, 1177 (1%3). 18. M. G. Miles, G. Doyle, R. P. Cooney and R. S. Tobias. Spectrochim. Acta 25A, 1515 (1%9). 19. A. L. Arduini, M. Garnett, R. C. Thompson and T. C. T. Wong. Can. J. Chem. 53, 3812 (1975). 20. G. Vicentini, L. B. Zinner, A. M. P. Felicissimo and K. Zinner. J. 1norg. Nucl. Chem. 41, 1611 (1979). 21. D. C. Stewart. Argonne National Laboratory Rep. ANL 4812, (1952). 22. J. H. Forsberg. Coord. Chem. Rev. 10, 195 (1973).