the presence of coordinated waters-". Evidencesin favour of bonding sites have been further sub-stantiated by the observations of v(M-N) andv (M-O) around 330 and 450 cm! respectively inthe far IR spectra.

In the electronic spectra of nickel complexesthree bands appear at 8·5 (7), 13·5 (7,2) and 24·6(17) k.K, assignable", to 3A2g ~ 3T2g (F), 3A2g ~ 3T}g(F) and 3A2g ~ 3T]g (P) trans~tions respectiv~ly. !>-comparison of the bands with those obtamed mthe reflectance spectrum indicates a possible disso-ciation in solution and presumably a distortedoctahedral configuration is expected for this com-pound. Cobalt complex exhibit three absorptionbands at 21 (19), 19·1 (32), 7·8 (8) kK attributableto 4Tg (F)~4TH (P), 4Tlg~4A2g (F) and 4Tlg~4T2g(F) transitions respectively. Molar absorptivityvalues and calculation of Dq and ~ indicate a spin-free octahedral configuration for this complex.

One broad band is observed in the case of coppercomplex around 17·0 (30) kK. The complex pre-sumably has a planar configuration.

From the analysis, conductance and IR spectralstudies Zn(II), Cd (II) and Hg(II) complexes arefound to be four-coordinated having a tetrahedralenvironment around the metal ions.

References1. MOHAPATRA. B. B., MOHAPATRA, B. K. & GURU. 5.,

Acta chim, hung., 94 (1977), 191.2. MOHAPATRA, B. B., :YIOHAPATRA, B. K. & GURU,S.,

.J. inorg. nucl. cu«; 39 (1977), 2291.3. MOHAPATRA, B. B., MOHAPATRA, B. K. & GURU,S.,

J. inorg. Chem., (in press).4. NAKAMOTO, K .• Infrared spectra of inorganic and coordina-

tion compounds (John Wiley, New York), 1963.5. GAMO, I., Bull. chem, Soc . [apan, 34 (1961), 760.6. LEVER, A. B. P., Inorganic electronic spectroscopy (Elsevier,

Amsterdam), 1968.

Detection & Determination of Piperidine &Piperazine Using Chloranil as a Reagent

U. MURALIKRISHNA & N. SOMESWARA RAO

Department of Chemistry, Andhra UniversityWaltair 530003

Received 1 }-,J arch 1978; accepted 14 April 1978

Spot detection and determination of microgramquantities of piperidine and piperazine using chloranilas reagent in chloroform are reported. The proce-dures now developed are based on the spectralcharacteristics of the Charge transfer complexesformed, and have the advantages of being simple,rapid and sensitive.

pIPERIDINE and piperazine interact withchloranil with the production of blue coloured

charge-transfer complexes at relatively low con-centrations of the donors-, showing maximumabsorption at 590 and 575 nm respectively. Thisproperty has been utilized in working out a procedurefor the spot detection and determination of thesetwo compounds.

Stock solutions of piperidine and piperazine(Fluka, purum) were prepared by dissolving 0·1 g of

NOTES

TABLE 1 - DETERMINATION OF PIPERIDINE ANDPIPERAZINE

Cone. (lLg/ml) contained infinal solution

Appr. range ofBeer's law

(lLg/ml)Taken Found

PIPERIDINE

4·559·05

11·4022'5042·6563·35

4'40")9·05 I

11·35 ~22·50 I42·65 I63'20J

10·50

PIPERAZINE

11·2520·5042·6566·0083·95

11'10")20·50 I42·60 ~66'OOJ82·80

20·80

each in chloroform (25 ml) a saturated solutionof chloranil (E. Merck, GR) in chloroform was pre-pared and filtered to get a clear solution. .

Absorption measurements were made WIth aUnicam SP-700 ultraviolet-visible recording spectro-photometer at room temperature (25°) using matchedsilica cells of 1 em path length. The s~ectra. ofthe mixtures of piperidine-chloranil and piperazmechloranil in chloroform were scanned against reagentas blank. However, it may be noted that chloranilin chloroform has no absorption in this region. Thecharacteristic new band for piperidine-chloranil isat 590 nm and for piperazine-chloranil is at 575 nm.

Procedure for the spot detection - Test solution(0'1 ml) was taken in the cavity of a spot plat~ andmixed with chloranil solution (0·1 ml) and dilutedwith chloroform to 0·3 ml. The solution is thoroughlymixed when a blue colour slowly developed within10 min.

From such a study, the identification and dilutionlimits are: For piperidine: 1·0 ug, and 1 :5'Ox 105

respectivley and for piperazine 5·0 fLg,and 1 :2·0 X 104

respectively.The method for the detection of piperazine was

applied with success in the case of somepharmaceutical preparations piperazine phosphateand piperazine citrate after extracting piperazineinto chloroform layer from alkali solution ofpiperazine salts. The' properly diluted solutiongave the test.

Procedure for the determination - To suitablealiquots of the nitrogen bases from the stocksolutions was added chloranil solution (1 ml) andthe contents made up to 10 ml by adding chloro-form. The absorbance of the piperidine solutionwas measured at 590 nm and that of piperazine at575 nm after 10 min. A calibration curve wasdrawn from the known results. The sample solutionwas then treated with an excess of the reagent (1ml of chloranil) and its absorbance measuredagainst the reagent blank in just the same manneras described for standard solutions. The amountof the unknown base was then read off from thecalibration plot. The results are presented in Table 1.

993

INDIAN J. CHEM., VOL. 16A, NOVEMBER 1978

The colcured solution are stable for two days, inproperly seated tubes.

We are grateful to the CSIR, New Delhi, for theaward of a junior research fellowship to one of us(N.S.R.).

References1. SOMESWARA RAO, N., Spectroscopic studies of charge

transfer and hydrogen bonded complexes, Ph.D. thesis,Andhra University. Waltair, 1976.

Solvent Extraction of Cu(lI) Using 4-Isonitroso-3-methyl-l-phenyl-5-pyrazolone

H. C. ARORA & R. K. TALRA

Department of Atomic Energy, Atomic Minerals DivisionNew Delhi 110022

Received 9 February 1978; accepted 25 }l1"ay 1978

Solvent extraction behaviour of Cu(I1) uslng 4-iso-nitroso-3-methyl-l-phenyl-5-pyrazolone (HIMPP) inbenzene as extracting agent has been studied. Com-position of the extracted complex has been determined.Interference due to a number of foreign elements hasalso been tested.

IN all earlier investigation, Arora et at.' studied thesolid metal complexes of 4-isonitroso-3-methyl-

1-phenyl-5-pyrazolone (HIMPP). Presently we reportthe use of this ligand for the solvent extraction ofCu(II). Interferences due to most of foreignelements likely to be present in alloys, ores andindustrial materials have been found to be negligible.

The ligand was prepared as described earlier!and its purity checked; m.p. 160°. It is soluble inbenzene, alcohol and chloroform. Stock solutionof copper (II) was prepared by dissolving knownweight of pure metallic copper in dilute (1:1) nitricacid. The solution was evaporated to dryness andfinally made up to a known volume with 0'1Nhydrochloric acid. Stock solution was diluted suit-ably to obtain Cu(II) solution containing copperequal to 10 fLgper ml.

Procedure - An aliquot of 1·6 X 10-4111 coppersolution (5 ml) and buffer solution (5 ml) were mixedand distilled water (10 ml) added to it. Themixture was shaken with a solution of HIMPP(20 ml) in benzene (6·16 X 10-4111) for 5 min at 25° ± 1°.The two phases were allowed to separate. Theamount of Cu(II) extracted into organic phase andthat left unextracted into aqueous phase was deter-mined spectrophotornetrically using sodium diethyldithiocarbamate reagent", Copper present in theorganic phase was stripped with 1:25 HCI (20 ml)prior to its determination. The distribution co-efficients (D) were calculated as usual. In all theexperiments the equilibrium pH Was measured.In the same fashion experiments were conductedat constant pH 4·9 by varying the ligand concen-tration from 0·3 to 2 m1l1, keeping the copperconcentration constant. It was observed that Cu(II)is almost completely extracted above PH 5·6 with6·16 X 10-4111 HIMPP in benzene. The slope of the

994

plots of log D vs pH and of log D vs log rHIMPPJis two in each case indicating that two 'moles ofhydrogen ions are liberated in the extraction processand two moles of ligand are involved in complexformation. Hence the extraction process may berepresented by the equation Cu2++2HIl\1PP ~ Cu(IMPP)2+2H+. The composition of the extractedcomplex is thus 1:2 (Cu-HIMPP).

In order to test the applicability of the methodfor t~e extr~ction of ~opper present in ores, alloysand industrial matenals, etc. a number of inter-ferences were examined by adding them to theaqueous solution containing 50 fLg of Cu(II) andsubjecting them to the general procedure maintain-ing the pH 5·4 and concentration of HIMPP2·46 X 10-3111 in each case. In some cases tartaricacid was successfully used to prevent hydroxideformation. The results indicate that barring AI(III)and Sn(IV), none of the foreign cations added (1 mgeach) hinders the complete extraction of Cu(II).The organic phase in each case was back washedwith 1: 25 HCl solution and analysed for Cu(II) andalso for interfering elements, if any. It was ob-served that Ni(II), Be(II), Mg(II), Ca(II), Mn(II),Fe (II I), Al(III), Th(IV), Sn(IV), Ti(IV), V(V) andU(VI) are not at all extracted alongwith Cu(II)whereas citrate, oxalate and ethylenediaminetetra-acetate anions seriously interfere. Phosphate andsulphate anions at 100 mg level are without anyeffect on the extraction of Cu(II).

References1. RU5TAGI, S. C., ARORA, H. C. & NAGESWARA RAO, G.,

Proceedings of the chemistry symposium, Vol. II (Depart-ment of Atomic Energy, India), 1972, 49.

2. SANDELL, E. B., Colorimetric determination of traces ofmetals, 1959, 448.

o-Mercaptoacetamidobenzoic Acid as aGravimetric Reagent for Zr(IV)

M. PADMINI & GEETHA PARAMESWARAN

Department of Chemistry, University of CalicutCalicut 673635

Received 7 October 1977; accepted 28 April 1978

Gravimetric determination of zirconium in pure saltsas well as in zircon has been carried out uslng o-rner-captoacetamidobenzoic acid (o-MAB). The resultsobtained are comparable to those obtained with mande-lic acid. The solid complex has been isolated and itsIR data reported.

SEVERAL organic reagents have been triedl-9 forthe gravimetric determination of zirconium

in its salts, alloys and ores. Since zirconium hasa less tendency to form stable complexes withsulphur donor ligands it was of interest to see ifo-mercaptoacetamidobenzoic acid (o-MAB), whichhas a -COOH group, besides -SH and -N donorsites, will form a complex with zirconium. It wasfound that zirconium forms a very stable complexwith o-MAB and this can successfully be used for