Prabhakaran, C. P.

Ram, A. N. Sunder

English

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INDIAN J. CHEM., VOL. 14A, JULY 1976Complex ColourTABLE 1- CHARACTERIZATION DATA 01' Zn(II) CoMPLEXESm.p. Zn (%) S (%)(0C)Found Reqd Found Reqd170 19·20 19'24 9'61 9'43198 14·41 14'09 7'04 6'91210 11'32 11'12 5'70 5-45Zn(acac).LZn(bzacltLZn(bzbz}.LWhiteGreyWhiteH.acac = acetyl acetone; H.bzac = benzoyl acetone; Hvbzbz = dibenzoyl methane; L = thiourea.The ~-diketonates of Zn(II) exhibit v(O-H)band ",3490 em? in the IR spectra (nujol) dueto the presence of a coordinated water molecule.When the ~-diketonates are reacted with thiourea,water molecule gets replaced by thiourea and thisis shown in the IR spectra of the mixed complexesin which v(O-H) band disappeared and a banddue to v(C-S) appeared ",710 crrr+, In thioureathe v(C-S) appears" 740 cm-l. In the mixedcomplexes, this band is shifted to lower frequency(",710 cm+) indicating definite metal-sulphurbonding in the adducts. Further, the resonatingring system present in the ~-diketonates gets dis-turbed by the introduction of thiourea ligand,in place of water molecule. This results in shiftingof v(C-C) and v(C-O) after thiourea has beenintroduced. The v(C-C) observed at 1600 crrr+in ~-diketonates was shifted to a higher frequency(ranging between 1610 cm-l and 1620 crrr+) inthiourea complexes. Hence, thiourea is definitelyborided to the zinc ion. The present complexesprovide examples of penta-coordinated complexesof Zn(II) with sulphur as one of the donor atoms.References1. MOHAPATRA, B. K. & RAMANA RAO, D. V., Z. anorg . allg.cu«, 372 (1970); 332.2. GRADDON, D. P. & WEEDEN, D. G., Aust. J. Chem., 17(1964), 607; 1052.3. GRADDON, D. P. & WEEDEN, D. G., Aust. J. Chem., 16(1963), 980.4. HAIGH, J. M., SLABBERT, N. r. & THORNTON, D. A., J.inorg, nucl, Chem., 32 (1970), 3635.S. VOGEL, A. I., A text book of quantitative inorganic analysis(Longmans, London), 1961. 467.6. SWAMINATHAN, K. & IRVING, H. M. N. H., J. lnorg, nucl.Chem.,26 (1964), 1291.Magnetic & Spectral Studies on Ni(II) & Cu(II)Complexes of N-(Salicylidene)phenylhydrazineA. N. SUNDER RAM & C. P. PRABHAKARANDepartment of Chemistry, University of KeralaTrivandrum 695001Received 9 September 1975; accepted 29 October 1975Ni(I1) and Cu(I1) form 1:1 complexes with theSchUl base (LH) derived from salicylaldehyde andphenylhydrazine. The physico-chemical data indicatea square-planar stereochemistry for the Ni(II) com-plex and a tetrahedral stereochemistry for the Cu(II)complex. A pyridine adduct of the nickel complex,NiL.PYI has also been isolated. The pyridine adductis paramagnetic and octahedral.536N-(SALICYLIDENE)PHENYLHYDRAZINE(LH) has been recommended as a gravimetricreagent for transition metals-. However, complexesof this ligand have not been investigated so far.We report here the preparation of Ni(II) and Cu(II)complexes of SPH and their characterization on thebasis of magnetic moment, conductance and elec-tronic and IR spectral data. A pyridine adductof the Ni(II) complex has also been prepared.The chemicals employed were of reagent quality.The solvents were purified by standard methodss.Preparation of the complexes - The complexeswere prepared by adding an aqueous solution ofthe metal chloride to an ethanolic solution of theSchiff base, LH, in an ammoniacal medium. Thebrown and the greenish-yellow precipitates obtainedin the case of Cu(II) and Ni(II) respectively werefiltered, washed with ethanol and ether and driedtn vacuo.The pyridine adduct of the Ni(II) complex wasprepared by refluxing an ethanolic solution of thecomplex with pyridine. The orange-yellow crystalsseparated were washed with ether and dried invacuo. The complexes were found to be insolublein water, but soluble in almost aJl organic solvents.Copper was estimated iodometrically after decom-posing the complex with nitric acid, while nickel wasestimated gravimetrically as dimethyl glyoximate.The analytical data of the Cu(II) and Ni(II)complexes correspond to the compositions CUL2and NiL2 while the pyridine adduct has the com-position NiL2PY2'The molar conductance values of less than unityfor 10-3M solutions in nitrobenzene show the non-conducting nature of the complexes.The IR spectrum (KBr) of the free ligand, whichhas three potential coordinating sites, exhibitsa sharp medium intensity band at 3300 crrr? whichcan be assined to '.IN-H. In the spectra of thecomplexes, this band does not show any shift indi-cating that coordination does not occur throughthe N-H group. A broad medium-intensity bandobserved around 2900 cm-1 in the ligand due tohydr?gen bonded -OH disappears on complexationshowing that hydrogen of the OH group is replacedby the metal ion. A medium intensity band at1530 em+ assigned to vC=N of a conjugated ringsystem= in the ligand is shifted to 1540 cm-l in itscomplexes showing that nitrogen of the C=N groupis involved in complexation. Thus, the IR dataindicate that the potentially tridentate ligand actsonly as a monovalent bidentate ligand making useof the oxygen of the -OH group and nitrogen ofthe azomethine group in coordination.The electronic spectrum of the Cu(II) complex(recorded in mull) in the solid state does not showany absorption in the range 600-700 nm whichexcludes the possibility of a square or distortedoctahedral geometry for this complex+ Keepingin view the steric factors operating in the ligand,the complex is likely to have a tetrahedral geo-metry5,6. A band observed at 360 nm can beassigned to an electronic transition associated withthe ligand. The Cu(II) complex shows a magneticmoment value of 1·74 RM.The electronic spectrum of the Ni(II) complexshows a band at 610 nm which is usually observedfor square-planar Ni(II) complexest-". The spec-trum shows another band at 440 nm which mayalso be assigned to one of the d-d transitions expectedfor square-planar Ni(II). The complex is dia-magnetic which conforms to the square-planargeometry of the compound. The pyridine adduct,however, is paramagnetic and its effective magneticmoment (3·17 H.M.) is typical of an octahedralNi(II) complex". Attempts to prepare similar pyri-dine adduct with Cu(II) complex were unsuccessful.The authors thank the authorities of the IndianInstitute of Science, Bangalore, and the PropellantEngineering Division of the Space Science Techno-logy Centre, Trivandrum, for the instrumentalfacilities. One of them (A.N.S.) is thankful tothe UGC, New Delhi, for financial assistance.References1. UMAPATHY, P. & ApPALA RAJu, N., Indian]. Chem., 2(1964), 248.2. WEISSBERGER, A., PROSKAUER, P. S., RIDDICK, J. A. &TROOPS, E. E., Organic solvents, Vol. VII (IrrtersciencePublishers, New York), 1956.3. UENO, K. & MARTELL, A. E., J. phys. Chern., 59 (1955),998.4. COTTON, F. A. & 'VILKINSON, G., Advanced inorganicchemistry (Wiley Eastern, . Iew Delhi), 1970, 901.5. SACCONI, L. & CIAMPOLINI, M., J. chem. Soc., (1964), 276.6. SACCONI, L., CIAMPOLINI, M. & CAMPIGLI, U., Lnorg,Chem., 4 (1965), 407.7. SACCONI, L., Transition metal chemistry, Vol. 4, edited byRichard L. Carlin (Marcel Dekker, New York), 1968,199.8. GRAY, H. B., Transition metal chemistry, Vol. 1. edited byRichard L- Carlin (Marcel Dekker, NewYork),1965, 240.9. FIGGIS, B. N. & LEWIS, J., Modern coordination chemistry,edited by J. Lewis & R. G. Wilkins (Interscience Pub-lishers, New York), 1960, 400,Polarographic Behaviour of U02(II) & Th(IV)in Ethane-l,2-dithiolR. S. SAXENA & S. K. BHATIADepartrnert of ChemistryMalaviya Regional Engineering College, JaipurReceived 7 May 1975; accepted 4 October 1975UO~+ and Tho+ ions in ethane-l,2-dithiol ~ive ir-reversible and diffusion-controlled waves in the pre-sence of O·IM NaCIO•• 0·002% Triton X-too and 25%ethanollc media. The values of kinetic parameters,viz. transfer coefficient (a), formal rate constant (KJ.h)for the electrode reactions have been determined byKoutecky's method as extended by Meites and Israel.The values of fiH, fiG and fiS have also been calcu-lated.NOTESIN continuation of our earlier workv+ the polaro-graphic behaviour of organo-sulphur compoundsand their complexes with metals>", in this note isreported the results of investigation on the behaviourof U02(II) and Th(IV) ions in the presence of ethane-I,2-dithiol for which there is no reference in theliterature.Ethane-lZ-dithiol (referred herein as EDT) andother chemicals used were of Analar (BDH) grade.A manual polarograph with scalamp galvanometerand SCE as reference electrode was used for recordingthe polarograms. The capillary had the followingcharacteristics in 25% ethanol, O·1M NaCI04 at-0·5 V vs SCE with hHg value of 40 ern: m=2·895mg/sec, t=2·39 sec.The effects of change in Hg-pressure, temperatureand concentration of metal ions on the waves due toUO~+ and Th4+ were investigated. The values ofkinetic parameters were determined from the pola.ro-grams of the solutions containing 1·0 mM UO~+ or0·1 mM Th4+ +O·IM NaCI04+O·002% Triton X-IOO+25% ethanol-j-different amounts of EDT. Thecurrent was recorded at the end of the drop lifeinstead of avera.ge current as the determination ofkinetic parameters is based on Koutecky's methodwhich are accurately reproduced by measuring themaximum current 6.The conventional log plots of the reduction wavesfor UOr and Th4+ in ethane-l,2-dithiol were linearand their slope values indicated the irreversiblenature of the waves for both the systems.The constancy of Idlh!fl in each case and thevalues of temperature coefficients of 1·138% (forU05+-EDT) and 1·838% (for Th4+-EDT) indicatethe diffusion controlled nature of the waves. Theplots of id vs temperature and h!fl are shown inFig. 1. The limiting current increases linearly withincrease in [metal ion]. With increase in EDT theE! shifts towards more negative potential s howingthe complex formation between metal ions and ligand,whereas id increases for UO~+ and decreases for Th4+indicating that the aqua-uranyl and aquo-thoriumions differ in size from their complexes of EDT.Since the reduction of UO~+ and Th4+ ions in thepresence of EDT is irreversible, it is consideredexpedient to determine the values of transfer coeffi-4 .Y-. 0....-.--- c __. .---...t...--~..-----.25·7432120 25 30TEMP:C35Fig. 1 - Plots of id versus temperature (curves A a-rt B)and plots of id versus h!~ (curves C and D) for the systemsUO~+-EDT (curves A and C) and Th4+-EDT (curvesB and D)537

Magnetic & Spectral Studies on Ni(II) & Cu(II) Complexes of N-(Salicylidene)phenylhydrazine

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Magnetic & Spectral Studies on Ni(II) & Cu(II) Complexes of N-(Salicylidene)phenylhydrazine

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