INDIAN J. CHEM., VOL. 21A, JUNE 1982

TABLE 3 - VALUES OF LOG K and LOG X OF TERNARY CoMPLEXES OF NICKEL(II), 01: THB TYPa MAB, MADs AND MAID.

(A = II-alanine, B = diols)

Ligand (B) /), log KMAB /),Iog KMABa /),Iog KMAIB log XMAB log XMABa log XMAaB

Ethane diol 0.9929 -2.1709 -1.0226 5.6768 9.2455 16.3035Propane-Lz- diol 1.3772 -3.0353 -1.07ffl 6.7208 10.2501 17.2".672-Butene-I,4-diol 0.3471 --4.4038 0.5973 5.5792 8.1464 8.7887Butane-2,3-diol -0.0066 --4.1200 -0.1771 5.0508 7.6900 12.6412Penrane-Z.a-diol 1.3022 -2.6913 -0.7271 6.6677 10.0834 18.7791Hexane-l,6-diol -0.5912 -3.7095 -3.1883 3.2273 4.0724 6.0105

CH C·O,3/ '0 OHHC, <:« "-

H2N?'~'OJ

? ~H20- C-CH

ICHJ

MA2BMAB

FIG.1' Tornary compl•• oIlypo MAEI, MAEl2 AND MA2B whore N.NlclcolIIlJA. Alanin. C~3

(HC -COOH) and EI.4iolsNH2

R- H2~ - ~H2'H2~ -~H-CHl' Hf, - CH. CH - ~H2

H:lC-~~H -CHJI HlC- C~ - CHiCH-CHl and

Kf.-C~-CH2-CH2-CHi~H2

and MAB2 complexes may be responsble for higher6 10gK and 10gX values in the former system";In this series of diols the complex of 2-butane-I,4-diol was found to be more stable which may be dueto participation in coordination of rr-electron densityof ring formed by the butene diol.

In these complexes three spin-allowed transitionsoccur around the regions 9615-10030 cm+! [3A211 -+3T2~ r~l)']' 15105-16103 crrr-' PAz" -+ 3Tl, (V2] and26040-27777 cm-1 [3A2• -+ 3TI, (P) (va)]. We haveused the sum of Vz and ~3 transitions for calculatingthe parameters B and ~6. The value of transitionenergy ratio V2/Vl varies from 1.51 to 1.64; Du/Bvaries from 1.02 to 1.24; ~ from 0.7678 to 0.9265,B from 799.13 to 964.53 in all these comlexes. Themagnitudes of D,,/B for MA2B complexes were largerthan those for the corresponding MAB2 species. Thisfinds parallel with the higher magnitudes of 6 10gKand 10gK for the former. The plots of ratio Dfll Bagainst stability constants ~ of complexes show alinear correlation. But negative slopes are observedsuggesting that increase in the magnitude of D,IBbrings about a decrease in the stability of the comp-lex species.

The positions of spectral bands are quite consistentwith octahedral stereochemistry ofNi(II). The posi-tions of spectral bands also indicate that the diolscoordinate as bideotate monofunctional moieties,The magnetic moments of these complexes(fable I) lie in the range 3.02-3.23 B.M. againsupporting our contention.

648

We are thankful to Prof. R. C. Kapoor, Head ofthe Chemistry Department for encouragement andfor providing laboratory facilities. Thanks are alsodue to the UGC, New Delhi for the award of JRFto two of us (R.K.J. & A.K.).

References

1. AHMAD,A. & MISRA,SUDHINDRAN., J. inorg, nucl. Chern.(Comm.).

2. AHMAD, A. & MISRA, SUOHINDRAN., Indian J. Chern.2tA (1982), 391. '

3. BJERRUM,J., Chern. Rev., 46 (1950), 381.4. NARAYAN,R. & DEY, A. K., Indian J. Chem., 14A (1976)

8n. '5. IRVING,H. & Rossorrl, H., Acta chem. scand., 10 (1956),

72.6. VOGEL,A. 1" A text book of quantitative inorganic analysis

(Longman, London), 1971, 256, 435.7. KONIG, E., Structure & Bonding, 9 (1971), 184.8. SIGEL, H., Chimia, 21 (1%7), 489.9. SIGEL, H., Angew Chern. Internat, Edn., 14 (1975), 394.

10. SIGEL, H., CoRACO, R. & Pans, B., Inorg, Chem., 13(1974), 462.

Physicochemical Studies on the Mixed LigandComplexes of I-Substituted Tetrazoline-5-thiones &

Ethylenethiourea with Chromium(III)

B. SINGH· & R. D. SINGHDepartment of Chemistry. Science College, Patna University,

Patna 800 005

Received 9 April 1981; revised and accepted 23 January 1982

A number of mixed ligand complexes of Cr(IIO with ethylene-tbiourea (ETU) and I-substituted tetrazoline-S-thiones!lUCb asI-pbenyltetrazoline-S-thione (IPTSTII), l-( p-dJ)orophenyl)tetra-zoline-5-thione (Ip-CIPTSTH) and 1-(p-tolyl)tetrazoline-S-thione(loTISTH) have been prepared and cbaractl'l'isod on tbe basis orCOIlductometric, magnetic and spectroscopic studies. In thesecomplexes ethylenethiOUl'ta is coordinated through sulphur butl-substituted tetrazoline-S-thiooes are coordinated throuldasulphur as weD as nitrogen. AD the complu.es are distortedoctahedral.

STUDIES on transition metal complexes of j ,substituted tetrazoline-S-thiones have received

considerable attention!"! However. complexes ofthese ligands with class a metal ions such as Cr(IIOhave been much less investigated+ As a part of ourprogramme on the study of mixed ligand complexes

of chromium, we report in this note the preparationand characterisation of a few more mixed complexesof Cr(IIQ using ethylencthiourea (ETU) as the pri-mary ligand and l-substituted tetrazoline-S-thiones(lST5TH) as the secondary ligands.

All the chemicals used were of AR or CP grade.l-Substituted tetrazoline-f-thiones were preparedby the method of Lieber et al:" Ethylenethiourea wasprepared by the method of J.V. Allan".

Preparation of complexes - Hexaaquochromium(Ilf) acetate, Cr(H20)6 (CH:lCOO)a, was prepared bythe method described in literature",

An aqueous solution of Cr(H20)6 (CHaCOO)a(0.005 mol) was mixed with an ethanolic solution ofethylenethiourea (0.015 mol) and the mixture (pH,....,7) was refluxed for e-- 6 hr. The colour of the solutionchanged from green to violet. The violet complex,pentaaquoethylenethioureachromium (III) triacetate,was obtained by evaporating this solution to dryness.It was washed with acetone and dried at 90 - 80°C.

Acetatohydroxo-Ivsubstituted tetrazoline-f-thio-natoethylenethioureachromium(III) complexes wereobtained as green precipitates by further refluxing theviolet solution with the l-substituted tetrazoline-Sthione ligands (0.015 mol) for 6-8 hr( pH ,....,7-8).These complexes were filtered, washed with ethanoland dried at 80-90°C. The analytical data of thecomplexes are given in Table 1.

The magnetic moments of the complexes weredetermined by the Gouy method at room temperature(3000A). Molar conductances were measured inDMF solutions using a Systronic conductometer. Allthe complexes are non-conducting in DMF exceptthe Cr(H20METU) (CH3COO)~ complex whichshows AM = 232 ohrrr-' em> mo l='. The infrared

spectra were recorded on a Perkin Elmer 577 spectro-photometer. Reflectance spectra were recorded on aHilger and Watts spectrophotometer model 700.

Analytical data as well as the conductivity datashow that stoichiometry of the pentaaquoethylene-thiourea complex is Cr (H20METU) (CHaCOO)3'Two of the mixed complexes with l-substitutedtetrazoline-5-thione and ethylenethiourea have thegeneral stoichiometry Cr(CHaCOO) (OH) (IST5T)(ETU) while the third mixed complex has theempirical formula Cr(CHaCOO)(OH)(1pCIPT5T)(ETU).2H20.

NOTES

It is well known that organic compounds contain-I

ing a thioamide (H-N-C=S) group give rise to fourthioamide bands9•tO around 1500, 1300, 1000 and800 cm=! respectively.

Agarwala and Raov', on the basis of normal coordi-nate analysis. suggested that the strong peaks at1530 and 1505 cm+! are due to the thioamide band-I,having main contributions from 8NH + vCN +8CH. Two peaks are observed because of two thioa-mide groups in ethylene thiourea. The 1200 cm-1peak is due to the thioamide band-II having majorcontributions from vC = S, vC = Nand 8N-H.The band-Il l also gets split and medium intensitybands are observed at 1040 cm-1 (vCH2--N +vC-C + vC = S) and 920 crrr+' (-CH2-N+vC-C + vC = S + vC:.:.:..N.The thioamide band-fVobserved at 685 cm-! as a medium intensity band hascontributions from vC = N, vC = Sand sym. ringdeformation modes.

The infrared spectrum of Cr(H20METU) (CHICOO)3 contains very broad bands at 3300, 1610 and400 cm-! corresponding to vOH, 80H and 1THOHmodes of coordinated water molecules-"!". Verystrong and broad bands at 1540 and 1440 cm-1 maybe assigned to the Va. COO and v,--COO modes ofthe acetate group in the complex. The difference of100 cm-1 between v, COO and v,COO modesindicates ionic nature of the acetate groups in thiscomplex>'. The thioamide band-I (8NH + vCN)observed at 1530 and 1505 crrr-! in the ligand appearsas a singlet at 1540 cm-! in the complex indicatingabsence of coordination through nitrogen. Thethioamide band-Il (vC = S + vCN) observed at1200 cm=! and thioamide band-Hi (vCN + vCS)observed at 1040 and 920 cm-l remain at the samepositions with considerable reduction in intensity.Coordination of ethylenethiourea through sulphuris indicated by the shift of thioamide band-IV(vC ~ S) from 685 cm-! in the ligand to 670 cm-1in the complex. This is further supported by thepresence of new weak bands in the complex at 510and 350 cnr+ which may have contributions fromvCr ~ OH?, and vCr-S modes of vibratlons'<-" res-pectively. Thus. the violet complex, pentaaquoethyle-nethioureachromium(III) triacetate, is an octahedralcomplex with five coordinated water molecules and

TABLE 1- ANALYTICAL AND MAONEllC MOMENT DATA OF THE CoMPLEXES

ComplexesFound (Calc.), % "",,If

(B.M.)C H N S M

Cr(H.O).{ETU)- 25.32 5.65 6.40 7.50 12.10 4.4(CH.COO), (25.65) (5.94) (6.65) (7.60) (12.35)Cr(CH,COO)(OH)- 35.60 3.42 20.30 15.40 17..60 3.97(l PTSn (ETU) (3S.38) (3.68) (20.60) (IS.72) (12.78)Cr(CH,COO) (OH)- 29.80 3.40 )7.4S 13.10 10.51 3.9(J pCIPTSn (ETU).2H,O (30.15) (3.76) (17.S9) (13.40) (10.89)Cr(CH,COO)(OH)- 37.40 4.10 20.11 14.90 12.08 3.77(10-TTST)(ETU) (37.05) (4.03) (19.95) (15.20) (l2·m

64~

INDIAN I. CHEM., VOL. 21A, JUNE 1982

one ethylenethiourea molecules coordinated throughsulphur. The three acetates are ionic. This observa-tion is in good agreement with the p.ert value of4.4 B.M. of this complex which lies in the expectedrange for octahedral Cr(IIl) complexes.

The infrared spectra of the mixed complexes Cr(CHaCOO)(OH)(L)(ETU). xH20, where x = 0 whenL = 1-phenyl-tetrazoline-5-thione and x = 2 whenL= I-parachlorophenyl-tetrazoline-5-thione indica-te that L is coordinated to the Cr(IIl) ion both throughimino-nitrogen as well as thiocarbonyl sulphur.This conclusion may be drawn from shift to lowerfrequencies ofthioamide band-I by 10-15 cm+! andtath of thioamide band-IV (vC .::.:.S) of the ligandsby 25-60 c01-1 on complexation.

The occurrence of a new band at 1240 cm-1 inthese complexes indicates the presence of a bidentateacetate group. The expected VOl COO and VI COOmodes merged to give a single broad band centeredat 1240 cm-I• The presence of hydroxo group isconfirmed by the presence of vOH and vCr-Obands19'20 at 3410-3425 and at 560 crrr-' respecti-velv,

The p.ert values of the present complexes have beenfound to be in the range 3.87-4.4 B.M. at 27°C.The values agree well with the expected values! of3.87-5.2 B.M. for octahedral Cr(IlI) complexes.

Thus. an octahedral structure (I) may be assignedto these complexes.

The reflectance spectrum of the complex, Cr(H20)5(ETU) (CH3COO)3 shows two bands at 19600 and25000 cm+! which may be assigned to the transitions(A2,(F) -+ 'T211(F) and 4A2lF) -+ 4T11I(F) respecti-vely. Thus, the IODq value of this complex is 19600em-I. The value of B' and {3 have been calculated tobe 6.125 and 0.6 respectively. There is 40 % reduc-tion in the free ion value of B for Cr(IIl) ion whichindicates considerable covalent character of the chromium-ligand bonds.

The reflectance spectrum of the mixed ligand comp-lex, Cr(CHaCOO) (OH) (lPT5T) (ETU) shows onlyone clear-cut band at 18900 crrr-' which may be assig-ned to the transition 4A2g(F) -+ 4T2U(F).Other d-dtransitions are overlapped by the charge-transferband occurring below 25000 crrr-'.

The authors are thankful to the authorities ofChemistry Department, Patna University for provid-ing facilities for this work.

References1. AGARWALA,U., NARAYAN. V. A. & DIKSHIT, S. K., Can.

J. Chem., 45 (1967), 1057.

650

2. AGARWALA,U. & DIKEHIT S. K. J. inore nucl Chern30 (1968), 1245. ' , .,.. .,3. AGARWALA,U. & SIKGH, B., Indian J. Chern 7 (1969)726. ., ,4. AGARWALA, U. & SIKGH, B., J. irore, ttucl Chern 33

(1971), 598. " . .,5. SINGH, B. & SINGH, R. D., J. inore. nucl. Chern 39

(1977), 25. e . .,

6. LIEBER,E. & RAMCHA2I.'DRAN,J., Can. J. Chern 37 (1959)1OJ. ., ,7. ALLEN, C. F. R., EDENS, C. O. & ALLAN, J. V., Organic

syntheses, Vol. 3 (John Wiley, New York), 1955, 394.8. BRAUER,G., A kana book of preparative inorganic chemis-

try, Vol. 2 (Acadomic Pross, New York), 1965, 1371.9. RAo, C. N. R. & VENKATARAGHAVAN,R., Spectrochim,

Acta. 18 (1962), 541.10. SUZUKI, 1., Bull. chem. Soc. Japan' 35 (1962) 1286

1449, 1456. ' ,11. AGARWALA,U. & RAo, P. B., Indian J. pure appl.phys.,

7 {19(9), 229.12. OHKAKU, N. & NAKAMOTO,K., Inorg, Chem, 10 (1971)

798. ' ,13. BRINK, G. & FALK, M., Can. J. Chem., 48 (1970), 2096.14. KOKOT, E., MOCKU.R, G. M. & SEFTON, G. L., Aust,

J. Chsm., 28 (1975), 299.15. HESTER, R. E. & PLANE, R. A., Inorg, Chem, 3 (1964)

768. ' ,16. SARTORI,G .. FURLANI, C. & DAMIANI,A., J. inorg: nucl-

Chem., 8 (1958), 119.17. WATT, C. W. & MCCoRMICK, B. J., Spectrochim, Acta

21 (1965), 753. '18. PRICE, E. R. & WASSON,J. R., J. inorg, nucl. Chem. 36

(1974), 67. '19. KROENKE, W. J. & KENNEDY, M. E., Inorg: Chem, 3

{196~~& '20. TOBIAS,R. S. & FREIDLINE,C. E., Inorg, Chem., 4 (1965)

215. '21. FIGGIS, ~. N. & LEWIS, J., Modern coordination chemistry

(Interscience, New York), 1960, 403.

A Polarographic Study of Glycine Complexes ofAntimony(IIl)

M. Y. MUZUMDAR& B. I. NEMADE*Dopartment of Chemistry, University of Bombay. Vidyanagari,

Bombay 400 098

Received 23 Marcil 1981; revised and accepted 26 December 1981

Complex formation beh'een glycine and Sb(III) has beenstudied polarographically at 30 ± O.I°C and I" =O.lM (KCI).The reduction is found to be quasi-reversible. The stabilityconstant of 1:1 Sb(nI)-gJycine complex comes out to be p-3.98 X1010.

COMPLEX formation of glycine with some metalions has been studied potentiometricallyv+,

Though the reduction of Sb3+ at d.m.e. has beenstudied in different complexing medias, thecomplexation behaviour of Sb3+ with glycine hasnot been studied and hence the need for titleinvestigation.

All the reagents used were of AR grade (BHD).Antimony trichloride solution was prepared bydissolving in cone. hydrochloric acid and was stan-dardized by using iodine solutions, All solutionswere prepared in doubly distilled water.

Polarograms of the deaerated solutions were recor-ded at constant ionic strength (0.1 M KCI). Potentials