The IR absorption spectra of some solid metal ion complexes of thio- and seleno-semicarbazide

910

Notes

In the terminal region of the spectrum (750-250 cm -~) there is a very characteristic feature due to the Fe(CN)s moiety (see [4, 8] and references therein), i.e. the medium intense band with peaks at 578 and 570 cm-', which must be mainly due either to a Fe-C stretching or a FeCN bending. The very weak bands following this doublet should be assigned to complementary Fe-C stretchings and/or FeCN bendings, to the Fe-N stretching, the FeNN deformations and the NH3 + torsion. Water librations are surely contributing to the absorption observed in this region. Peaks developed at 430 cm -1 and 370cm-' by cooling at -196°C are perhaps due to such vibrations.

Acknowledgements--To Consejo Nacional de Investigaciones Cientificas y TGcnicas for financial support. To Universidad National de Tucumfin for a grant to N.E.K. Dr. J. C. Merodio (FCE, UNLP) and the Laboratory of Microanalysis (FFyB, UBA) are also gratefully acknowledged.

X-ray powder diffraction data Data obtained from the powder diffractograms are included in Table 3. No indexing could be given to the diffraction peaks.

1. K. A. Hoffman, Z Analyt. Chem. 12, 158 (1896). 2. E. Biesalski and O. Hanser, Z. Anorg. All?,. Chem. 74, 384 (1912). 3. V. V. Zhilinskaya, Yu. P. Nazarenko, Yn. I. Bmtusl'Ro and K. B. Yatsimirskii, Russ. J. Inorg Chem. 19, 1197 (1974). 4. J. A. Olabe and P. L Aymonino, £ Inorg. Nucl. Chem. 36, 1221, (1974). 5. N. E. Katz, M. A. Blesa, J. A. Olabe and P. J. Aymonino, to be published. 6. A. Nieuwpoort and J. Reedijk, Inorg. Chim. Acta 7, 323 (1973). 7. L. F. Audrieth and B. Ackerson Ogg, The Chemistry of Hydrazine. Wiley, New York (1951). 8. J. A. Olabe and P. J. Aymonino, J. lnorg. Nucl. Chem. 38, 225 (1976). 9. L. A. Gentil, J. A. Olabe, E. J. Baran and P. J. Aymonino, Z Thermal Anal. 7, 279 0975). 10. R. Tsuchiya, M. Yonemura, A. Uehara and E. Kyuno, Bull. Chem. Soc. Japan 47, 660 (1974). l l . B . Moha~, Acta Chim. Acad. Sci. Hung. 62, 217 (1969). 12. S. Glasstone, An Introduction to Electrochemistry. Van Nostrand, New York (1942). 13. (a) P. A. Giguere and I. D. Lin, J. Chem. Phys. 20, 136 (1952); (b) J. C. Decius and D. P. Pearson, J. Am. Chem. Soc. 75, 2436 (1953); (c) R. G. Snyder and J. C. Decius, Spectrochim. Acta 13, 280 (1959); (d) W. G. Paterson and M. Onyschuk, Can. J. Chem. 39, 986 (1961); (e) L. Sacconi and A. Sabatini, J. Inorg. Nucl. Chem. 25, 1389 (1963); (f) J. R. Durig, S. F. Bush and E. E. Mercer, J. Chem. Phys. 44, 4238 (1966); (g) D. Nicholls, M. Rowley and R. Swindells, J. Chem. Soc. (A) 950 (1966). 14. V. L. Goedeken, L. M. Vallarino and J. V. Quagiiano, lnorg. Chem. 10, 2682 (1971). 15. E. A. V. Ebsworth and N. Sheppard, Spectrochim. Acta 13, 261 (1959).

Table 3. X-ray powder diffraction data for Na2[Fe(CN)sNaHs].2H20

d (°A)

I/Io

7.195 5.910 5.795 5.470 5.095 4.90O 4.610 4.230 4.030 3.790 3.390 3.040 2.875 2.687 2.521 2.429

30 20 44 42 20 24 16 40 64 46 20 18 36 100 30 22

tOn leave from Facultad de Bioqulmica, Qulmica y Farmacia, Universidad Nacional de Tucumfin, R. Argentina. ~Presently at the Departamento de Polftica Cientifica y Tecnol6gica, Universidad Nacional de Lujfin, R. Argentina. §Member of the "Carrera del Investigador Cientifico" (CONICET, R.A.).

Cdtedra de Qufmica lnorgdnica Facultad de Ciencias Exactas, U.N.L.P. 47 y 115, La Plata Rep~blica Argentina

N. E. KATZt J. A. OLABE~: P. J. AYMONINO§

REFERENCES

J. inorg, nucl. Chem., 1977, Vol. 39, pp. 910-912. Pergamon Press. Printed in Great Britain

The IR absorption spectra of some solid metal ion complexes of thio- and seleno.semicarbazide (Received 6 October 1976) X-ray crystallographic studies have shown that thiosemicarbazide acts as a bidentate ligand, linking through sulphur and the hydrazine nitrogen to metal ions such as nickel(II)[l] and zinc(II)[2], but as ~a monodentate ligand, linking via sulphur only to silver(I)[3]. The difference in action can be explained by the fact that silver(I) shows strong class0a)[4] metal acceptor properties linking strongly to the heavier donor atom sulphur whereas nickel(H) shows borderline and zinc(II) shows class(a) bebaviour. In the present work we hoped to correlate the IR spectra of the solid metal complexes with their structure where it is known and extend the study to the analogous selenosemicarbazide complexes. The only previous study [5] of the IR spectra of the latter complexes was very brief. EXPERIMENTAL

The solid complexes were normally prepared by mixing metal salt solutions with warm solutions of the ligands, in the correct

molar ratio, both solutions being at least 0.1 M in acid to avoid hydrolysis. Selenosemicarbazide was prepared as described previously[6[. The complexes were analysed for metal, sulphur (or selenium) and nitrogen and the results, in general, ageed well with the expected values. The IR absorption spectra were measured with the substance in KBr phase using a Perkin-Elmer 137 spectrophotometer. The absorption bands are listed in Tables i-4. DISCUSSION

The most interesting observation was that, on the basis of the similarity of the spectra, the complexes fall into two distinct groups; those of nickel(HD, copper(]]) and zinc(I1) in which the ligand is bidentate and those of mercury(LI), silver(I), cadmium(II) and copper(I) in which we think the ligand is monodentate linking to the metal ion only by the sulphur (or selenium) atom. The assignment of the bands is based on earlier studies of the

Notes

911

Table 1. IR absorption frequencies (in cm-'), L =thiosemicarbazide

Table 3. IR absorption frequencies (in cm '), L = selenosemicarbazide

Assignments

Assignments

L

NiL2(NO3)2 Cula(NO3)2 ZnLC12

3328s 3218s 3120s

3319s 3212s 3027s 2912s

3297s 3202s 3027s 2938s

8(NH~)

1645s 1619s

1636s 1607s

1626s 1597s

Combination bands:

1523s 1477sh

1560w 1430s

1560w 1436s

v(NH)

v(CN)

8(NI-I2) fl(NH2)

v(CS)

3506s 3330s 3233s 3142s

L

NiL2(NO3)2CuL2(NO3)2 ZnLCI~

~fNH)

3267s 3174s 2940s 2889s

3256s 3174s 3075s 2932s

1636s 1597s

8(NH2)

1639s 1610s

1628s 1599s

1625s 1602s

1627s 1613s

1543s 1426s

Combination Bands:

1515s

1549w 1417s

1531m 1419s

1380s

v(CND 8(NH2)

1540w 1426m 1376m

1274s 1159s 1008s 995s

1234s l141m

1217s 1148m 1010w

1211s 1122s 1028w

1313s 1277s

fl(NH2)

1159s 999s

1236s 1135w 989w

1209m ll45m 999m

1217s 1133s 987w

803s

701s

696s

691s

thiosemicarbazide complexes [7] and of selenosemicarbazide and related compounds [8, 9]. The spectral data is listed in Tables 1-4. The differences between the two groups of complexes can be summarised. 3400-3000 era- 1 The three strong bands in the ligands due to N-H stretching are replaced by three sharper bands in the complexes where the ligand is monodentate and linked to the metal only through sulphur (or selenium), but are replaced by four bands where the li~nd is bidentate and linked to the metal through the hydrazine nitrogen as well as the sulphur (or selenium), the environment of the two NH2 groups in the molecule thus becoming different. 1300-1200 cm-~ The band at about 1275cm-' in the free ligand, which has been attributed to NH2 deformation, is tittle changed in the complexes where the ligand is monodentate but is reduced by 40-70 era-' in the bidentate complexes. 800.-650cm -~

The band at 803 cm-' in the thiosemicarbazide spectrum is

v(CSe)

1354m

993w

760m

attributed primarily to C=S stretching and that at 760 cm- ' in the selenosemiearbazide spectrum to C=Se stretching. In the complexes where we think the ligand is bidentate the C=S stretching band is shifted down by 100cm-~ and in the case of the selenium ligand the equivalent C=Se band disappears completely due we think to the reduction of the frequency below 650era -' the lower limit of our measurements. This is what we would expect as bonding of the metal to the sulphur (or selenium) atom would reduce the C---Sand C=Se bond strength. On the other hand it was surprising to find that these C--S and C=Se stretching frequencies were orgy reduced by some 10era -~ in the complexes where we think the ligand is monodentate and linked to the metal solely by the sulphur (or selenium) atom. Other workers [9] have suggested that the bands at 803 and 760 era-' are not solely due to C=S and C=Se stretching respectively but contain contributions from other vibrations notably C-N stretching. The small reduction in the frequency of these bands in the case of the monodentate ligand complexes could be explained ff the reduction of the C=S bond strength when the sulphur is linked to the metal is compensated by an increase in the C-N bond strength due to a mesomeric shift ~ 2÷. Such a shift would be inhibited in the NH2--NI~--C&S--)M bidentate ligand complexes because the NH2 group would also be linked to the metal ion.

Table 2. IR absorption frequencies (in cm-1), L = thiosemicarbazide

Assignments u(NH)

8(N1-I2) Combination bands:

HgL2(NO3)2 A g L C !

Ag2L3(NO3)2

CdL2(NO3)2 CuL2CI

3290s 3196s 3097s

3341s 3223s 3112s

3324m 3228s 3117s

3291s 3197s 3117s

3341m 3183s 3094s

1643s 1593s

1628s 1602s

1617s 1594s

1637m 1605s

1634s 1583s

1537w

1521s 1461m

1517m 1451w

1538w 1420s

1519s 1499m

1313m 1267w i 176w 997m

1299s 1269s 1149m 987s 906m

1296m 1265m 1149w 991m

1197w 1159w 1043m 1002m

1282w 1250w 1169m 993m 943m

78903

789s

789m

796m

792s

~(CN) 8(NI-I2) /3(NH2)

v(CS)

3364s 3276s 3195s 3122s

3287s 3183s 3077s

912

Notes Table 4. IR absorption frequencies (in cm-~), L = selenosemicarbazide Assignments v(NI-I)

8(NH2) Combination Bands: v(CN-) 8(NH2) (NH2)

v(CSe) Department of Chemistry University of Ibadan Ibadan Nigeria

H g L 2 ( N O 3 ) 2 AgLC1

Ag2L3(NO3)2

CdL2(NO3)2

CuL2CI

3341s 3244s 3132s

3330s 3223s 3122s

3330s 3223s 3122s

3330m 3228m 3152s

3355m 3255s 3155s

1658s 1605s

1650s 1610s

1636s 1597s

1654s 1601m

1640s 1596s

1535w 1405s 131 lw 1287m 1175w 1023w 991m

1538m 1468m 1376m 1274s 1158m 100%

1512w 1457w

1533m

1566m

1264m 1153m 1007m

1275m 1165m 1017m 985m 823m

1266m 1150m 1010m 996m %0m 924m

752m

762m

749m

746m

J. ADEMOLA ADEJUMOBI DANIEL R. GODDARD

REFERENCES 1. R. H. Groenback, Acta Chem. Scan& 22, 2171, 2809 (1968). 2. L. Cavalca, M. Nardeili and G. Branchi, Acta Cryst. 13, 688 (1%0). 3. G. F. Gasparri, A. Mangia, A. Musatti and M. Narderii, Aeta Cryst. B24, 367 (1968). 4. S. Ahrland, J. Chatt and N. R. Davies, Quart. Rev. 12, 256 (1958).

746m

5. A. M. Romanov, A. V. Ablov and N. V. Gerbelen, Russ. J. Inorg. Chem. 14, 196 (1969). 6. D. R. Goddard, B. D. Lodam, S. O. Ajayi and M. J. Campbell, J. Chem. Soc. (A), 506 (1969). 7. M. Mashima, Bull. Chem. Soc. Japan 37, 974 (1964); M. J. Campbell and R. Grzeskowiak, J. Chem. Soc. (A), 396 (1967); D. M. Wries and T. Suprunchuk, Can. J. Chem. 47, 1087 (1969); B. B. Kedzia, Bull. Acad. Pol. Sci. Ser. Sci. Chem. ~0, 565, 573 (1972); M. J. Campbell, Coord. Chem. Rev. 15, 279 (1975). 8. C. Collard-Charon and M. Renson, Bull. Soc. Chim. Belg. 72, 291 (1963); B. A. Gingras, T. Suprunchuk and C. H. Bayley, Can. J. Chem. 43, 1650 (1965). 9. D. M. Wries, B. A. Gingras and T. Suprunchuk, Can. J. Chem. 45, 469 (1967); G. B. Aitken, J. L. Duncan and G. P. McQuillan, J. Chem. Soc. (A), 2695 (1971).

J. inorg, nuel. Chem., 1977, Vol. 39, pp. 912-913. Pergamon Press. Printed in Great Britain

A spectrophotometric and calorimetric study oi complex formation between nickel(H) and semicarbazide and its sulphur and selenium analogues (Received 6 October 1976) A previous study of complexes of the silver(I) ion[l] with semicarbazide and its sulphur and selenium analogues revealed the normal class (b)[2] stability and enthalpy order for the donor atom O <~S < Se. The enthalpy order for copper(H) complexes [3] was the same but the stability order was O ¢ S > Se indicating mixed class (a)--class (b) character. The present work involves the study of the complexes of the nickel(II) ion to see how they compare with those of the copper(II) ion. EXPERIMENTAL Absorbance measurements (200-1000 nm) were made at 300 on mixed solutions of nickel(ID ion and the appropriate ligand in 0.01 M HNO3 with ionic strength adjusted to 0.1 M with KNO3 (HC10, was used for measurements below 300 urn). Solutions of selenosemicarbazide were freshly prepared and protected from light to prevent decomposition[,;]. Addition of the ligand to the nickel solution caused an increase in absorbance and a shift to shorter wavelengths. In the case of thio- and selenosemicarbazide

the short wavelength maximum of the nickel(If) ion could not be observed as it was obscured by an intense UV absorption which is probably a charge transfer band. Using Coleman's treatmant[5] for deducing the number of absorbing species and Job's method [6] for identifying the complexes, the data was interpreted in terms of the formation of the complexes NiL22+ and NiL~2÷ (L = ligand). The extinction coefficients for NiL~ ~+ and NiL32+ were estimated using excess metal ion and excess ligand respectively but since complex formation was never complete the provisional values were used to obtain stability constants and then the two sets of values were refined successively until constant. The calorimetric measurements were made using an adiabatic calorimeter described previously[3]. The absorption maxima are listed in Table 1 and the thermodynamic data in Table 2. DISCUSSION

We assume that the ligands are bidentate linking to the nickel ion via the hydrazine nitrogen and oxygen (or sulphur or selenium)