Complexes of acetylurea with rare earth perchlorates

1892

Notes

5. M. N. Hughes, M. Underhill and K. J. Rutt, J. Chem. Sot'. Dalton Trans. 1219 (1972). 6. V. C. Patel and N. F. Curtis, J. chem. Sot'. (A), 1607 (1969). 7. M. N. Hughes, B. Waldron and K. J. Rutt, Inorg. Chim. Acta 10, 619 (1972). 8. S. C. Rustagi and G. N. Rao, Curr. Sci. 42, 351 (1973).

9. R. L. Dotson, J. inorg, nucl. Chem. 34, 3131 (1970). 10. W. W. Wendlandt and J. P. Smith, The Thermalproperties of Transition Metal Ammine Complexes. Elsevier, Amsterdam (1967). 11. A. B. P. Lever, Inorganic Electronic Spectroscopy. Elsvier, Amsterdam (1968).

J. inorg,nucL Chem., 1974, \ ol. 36, pp. 1892-1896. PergamonPress.Printedin Great Britain.

Complexes of aeetylurea with rare earth perchlorates (First received 22 May 1973: in ret,ised]brm 27 August 1973)

RECENTLY, we reported the adducts formed by reaction of diacetamide[l], di-n-butyramide[2] and dipropionamide[3] with lanthanide perchlorates. Previously Seminara et a/.[4] reported the coordination compounds of biuret with trivalent lanthanides. In all cases there is good evidence that the coordination between metal ion and ligand occurs through the two oxygen atoms, illustrating the effectiveness of the - C O N H C O group in these ligands. Since acetylurea (AU) contains the same group, we felt that similar coordination compounds could be prepared from this ligand and trivalent lanthanides. Recently some compounds with AU and metal halides have been reported[5]. Our research has been concerned with the synthesis and characterization of a series of compounds: Ln(C104)3.4AU (where Ln = La-Yb, Y; AU = H3C-CONHCO-NH2).

EXPERIMENTAL

Reagents AU was prepared by heating a mixture of acetyl chloride, acetic anhydride, urea, and a trace of sulfuric acid[6, 7]. The crude products were purified by recrystallization from ethanol. The hydrated lanthanide perchlorates were prepared as reported in our earlier work[2].

Preparation q['the compounds A suspension of AU in chloroform was added dropwise to an ethyl acetate solution of hydrated perchlorate with stirring, and was heated to the boiling point. Precipitation of the product occurred immediately, with the heavier lanthanides. The lighter ones could be forced out of the solution by addition of trimethyl orthoformate which acts

Table 1. Summary of analytical results for the compounds of formula Ln(CIO4)3.4AU

Ln

Lanthanide Calcd Found

Analysis (~,,) Perchlorate Calcd Found

Nitrogen Calcd Found

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Y

16-42 16.54 16.62 16.95 17.54 17.70 18.20 18.36 18.69 18.92 19.14 19.29 19-67 11-17

35.28 35.23 35.19 35.06 34.81 34.74 34.53 34.46 34.32 34.22 34.13 34.06 33.91 37.49

13-25 13-23 13-22 13.17 13.07 13.05 12.97 12.94 12.89 12.85 12.82 12.79 12.73 14.08

16.34 16.49 16.53 16.86 17-63 17-75 18.09 18.50 18.61 18.87 19.09 19.41 19.70 10.97

35-40 35.22 35.26 34.84 35.02 34.76 34.38 34.30 34.28 34.38 34.02 33.88 33.79 37.50

13.10 13.20 13.32 12.98 12.86 12.90 12-84 12-78 12.79 12.73 12.74 12.63 12.50 14.03

Notes

II

~

I

~

~

.~

.

~

~ - = ~

2

~.~:

,.,

r--

.t,

r,l

r--

-,=

.

.

.

~

t

.

t

.

~

~

~

~

.-

.

~,~-~.,

~ ~ ~ - '~= ~ >-

,-,

=

.

1893

~

o

~

.c

~

~ ° ~ 0 0

~

o~g

=~

~

x: ~ >~ ~ ~ ~

~

~,--,~.

,,o

~-.~,12z ~ ~ ' ~ - = ~ g ~

~.

.,.-.

-£

E

< m*"

~-

nq

,4D

r'--

~

cq

oo

L~

,.zb ,.0

E

4"" 4"

o

-.4- ~; ~ ~ 2 ,,--

" =" - "= ~ ~

22

,,,.J

Y {.-r~

t,--, r q c,4 r-- r-t*~ r,'~, t'm,

,,o "~1"

r~-, t l

--

--

~

~

~

~-,

,.q

o

..£..£.

~, • 1

r-i

rq

rt

oocq

~

t,q

.E

Lr~ ,,4D

tq

i

...o F'

,'£

i

Ii =x

.c

_c.c

.~..~ ~,

,-. ~ ,~

•

. . . . .

>

! E

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~

~.

E

r-I

¢.

>

1894

Notes

70,0

// / ~o" SO,O

2 < I

30,O-

/

lO,O-

/

4

/

/

/

/

/

/

/

/

/ -

1,00

-

3/00

,

r

5,00

7,00 x/~'T~102

Fig. 1. The behaviour o f A o - Ae for Tm(CIO,~)3.4AU in acetone at (25.0 _ 0-1)°C. Ao and Ae are equivalent conductance at infinite dilution and equivalent concentration, respectively.

as a dehydrating agent[8]. The precipitates were filtered hot, washed with dry chloroform, and recrystallized from a 1:5 mixture ofiethanot chloroform. The crystals were dried initially in a vacuum desiccator over calcium chloride; and finally at 100°C (0,1 mm) over phosphorus pentoxide in abderhalden apparatus. Analytical procedures. Perchlorate and lanthanide were determined using the procedure reported previously[2]. Nitrogen was determined by the Kjeldahl method[9]. The results are presented in Table 1.

Measurements IR. spectra were determined using a Perkin-Elmer Model 337 Spectrophotometer in the region 4000-400 cm-~. The complexes were examined as mulls in Fluorolube and Nujol, in the regions 2.5-8.0# and 7,5-2-5# respectively, Raman spectra were obtained of the solid in a sealed capillary using the 4880 A line of the Jarrel-Ash Raman Laser Spectrophotometer, Conductance measurements were carried out in acetone, using a Metrohm Konduktoskop E 365 B bridge, at (25-0 +__ O.I)°C. X-ray powder diagrams were obtained using a Norelco X-ray Instrument with diffractometer from Phillips Electronic Instruments, with a CuKct radiation. RESULTS

AND

DISCUSSION

The assignments of the ligand vibration of our complexes were made based on the early vibrational analysis of acylureas reported by Uno et al.[10] as shown in Table 2. Our complexes show three bands near 3470, 3355 and

3270 cm-~ which are shifted to higher frequencies relative to those of the free acetylurea. The first and third bands, which correspond to the NH 2 asymmetric and symmetric stretching vibrations, are most affected. This frequency shift can probably be explained by a change in the structural configuration of the tigand after complexation. Such behaviour is observed for the biuret, which in the hydrated state has a trans configuration with a strong intramolecular N - H . . . O hydrogen bond[11]. This configuration can be preserved in crystals of bis (biuret) cadmium chloride[12]. A different situation occurs with Zn 2+ ion where the chelation energy is sufficient to break the intramolecular hydrogen Table 4. X-ray diffraction patterns of the compounds of formula Ln(CIO4)3.4AU La

I/lo

Ce d(A}

2.9 1,7

11.18 8.51

f-3 3.5 10,0 3,0 6-4 5,2 2,1 2.9 1.0 1.0

6.91 6.39 5.90 5,60 3,69 3.62 3.45 3.29 2-93 2.69

1/Io

Pr

d(A)

I/I o

d(h)

1-8

11,10

4.5

11-t2

1.7 1-3 3-2 10.0 1.8 6-0 4.5 2.0 2-3 t .0 1.0

7.65 6-91 6-34 5,89 5.57 3-66 3.62 3.45 3.28 2-93 2.69

1.2 2.2 2.4 10-0 3.3 4-6 3.2 2-5 2-3

7.66 6.91 6.36 5-90 5,60 3-66 3.62 3-45 3.28

1.0

2-69

Notes

1895

[>I ~ i~'~':'~'=~'~~-~'=" I

..-.

~

id~'.~',~'A~'+~~

~,~,'~,&~

0

E

E

~

~,,,~,,~-,5.~-~-~,~,-~,..6

~c:~

8

~_ ~-

Ei E

m

v

f-

1

J

~ - -

~,

. ~

~

1896

Notes-

bond[13]. If our case resembles the latter situation, we can expect the NH2 vibrations to be shifted to higher frequencies. This explanation is supported by a recent i.r. study, which showed the existence of intramolecular hydrogen bonding between the carbonyl and NH groups of various substituted acetylureas in solution[14]. The carbonyl stretching vibrations are observed near 1715 c m - ~ and probably the shoulder at 1685 c m - ~. The v3 bands of perchlorate appear very broadly at 1140 and 1110 cm 1. This band splitting as well as the intensification of the v~ band, which appears strongly at 928 940 cm-~ in the R a m a n spectra (see Table 3) is interpreted as a solid state effect[15]. This intensification is easier to observe for heavier elements since for lighter ones this band may be overlapped with the CN stretching band of the ligand, which appears at 940 c m - t. The X-ray diffraction patterns show the existence of two isomorphic series (Tables 4 and 5j: L a - P r and Nd Yb, Y. Only one series was observed for imide complexes[3]. The conductance values range between 164-171 fl 1 cm 2 . mole-~ (Table 6). The values are low since at millimolar concentration, ionic association is occurring, as shown in Fig. 1. The experimental slopes (Ao A e ) / , , ~ of 975 (Ce) and 1260 (Tm) are of the same order of magnitude as those observed for Ln(CIO4)3.L4 (L = acyclic imide) complexes[2, 31, an observation which can be correlated with a 1 : 3 electrolyte type.

Acknowledgements--The authors express their thanks to Dr. Yoshio Kawano of Laboratorio de Espectroscopia Molecular da Universidade de S~,o Paulo for R a m a n Measurements, to Instituto Agron6mico de Campinas for the use.of X-ray equipment. Thanks are also due to Funda~;go de Amparo a Pesquisa do Estado de S~,o Paulo for financial support.

Instituto de Quimica Universidade Estadual de Campinas Caixa Postal. 1170 13.100 Campinas~ Sdo Paulo Brazil

REFERENCES

1. C. Airoldi and Y. Gushikem, J. inorg, nucl. Chem. 34, 3921 (1972). 2. Y. Gushikem, C. Airoldi and O. L. Alves, J. inorg, nucl. Chem. 35, 1159 (1973). 3. O. L. Alves, Y. Gushikem and C. Airoldi, J. inorg, nucl. Chem. 36, 1079 (1974). 4. A. Seminara, A. Musumeci and G. Condorelli, Ann. Chim. 59, 978 (1969). 5. R. C. Paul, S. Good and S. L. Chadka, J. inorg, nucl. Chem. 33, 2703 (1971). 6. E. A. Werner, J. chem. Soc. 109, 1120(1916). 7. R. W. Stonghton, J. org. Chem. 2, 514 (1938). 8. P. W. N. W. van Leeven and W. L. Groeneveld, Inorg. nucl. Chem. Lett. 3, 145 (1967). 9. I. M. Kolthoff, E. B. Sandell, E. J. Meehan and S. Bruckenstein, Quantitatice Chemical Analysis, p. 791. Macmillan, London (1971). 10. T. Uno, K. Machida, K. Hanai and Y. Saito, Bull. chem. Soc. Japan 42, 619 (1969). 11. E. W. Hughes, H. L. Yakel and H. C. Freeman, Acta crystallogr. 14, 345 (1961). 12. L. Cavalca, M. Nardelli and G. Fava, Acta crystallogr. 13, 594 (1960). 13. M. Nardelli, G. Fava and G. Giraldi, Aeta crystallogr. 16, 343 (1963). 14. C. I. Jose and P. R. Pabrai, Spectrochim. Acta 23A, 734 (1967). 15. S. D. Ross, Spectrochim. Acta 18, 225 (1962).

C. A I R O L D I Y. G U S H I K E M

J. inorg,nucl. Chem., 1974, Vol. 36, pp. 1896--1898.Pergamon Press. Printed in Great Britain.

Octahedral cobalt(Ill) complexes of the chloropentammine type--XXXI Preparation, properties and reactions of the cis-chloro(cyanoethylamine)bis(ethylenediamine) cobalt(liD complex

lReceived 20 April 1973)

IN NEUTRAL and basic solutions, cis-chloro(cyanomethyla mine)bislet hylenediamine)cobaltt I l I )chloride[ 1] undergoes linkage isomerization to the trans-chloro(aminoacetonitrile) isomer at rates that are very much higher than those of its hydrolyses, but in acidic aqueous solutions this isomerization is so retarded that kinetics of its solvolysis can be studied. At some stage in the linkage isomerization, both ends of the cyanomethylamine ligand must become temporarily bound to cobalt :

CH2 C o - N H 2 . CH 2 . C - N --* C 6/ NH2 ~N =

I

C

Co N - - - C . C H 2 . N H 2 The facility of such a process arises from the fact that the two nitrogen atoms in cyanomethylamine are suitably spaced for formation of a ring of relatively low strain