Bembi, Ramesh

Malik, Wahid U.

Verma, B. B.

English

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INDIAN J. CHEM., VOL. 14A, AUGUST 1976Polaroaraphic & Spectral Studies on theReaction of Fe(III) withPentacyanonitrosylmanganateWABID U. MALIK-, RAMESH BEMBIt & B. B. VERMADepartment of Chemistry, University of Roorkee, RoorkeeReceived 6 JuJJe 1975; accepted 28 November 1975Fe(III) reacts with KI[Mn(CN),NO] to aive a areensoluble complex in dilute solution (~O·OOIM) and asolid complex in concentrated solutions (~ O·I-O·OIM).Spectrophotometric and polaro araphic studies confirm1 : 1 stoichiometry for the complex. The stabilityconstant of the complex is 5·0 x 10'. The complex hasthe formula Fe[Mn(CN),NO).:2H.O. That the iron in thecomplex is ionic and in +3 0xidation state is supportedby mapetic, IR and M()ssbauer spectroscopic data.pOTASSIUM pentacyanonitrosylmanganate,KI[Mn(CN),NO], is very stable and reactsl,2 withheavy metal ions, except Fe (III) , to give colloidalprecipitates'. However, Fe(IU) reacts with it togive either a green-colonred soluble complex or agelatinous precipitate depending upon the concen-tration of Fe (III) solution. Investigations on thiscomplex in solution form as well as in the solid statehave now been carried out employing techniqueslike polarography, IR and Mossbauer spectroscopyand magnetic measurements.Potassium pentacyanonitrosylmanganate was pre-paredt from KaMn(CN). and its solution standardizedpotentiometrically' by titrating against KMnO,.Ferric chloride (Analar grade, BDH) solution wasstandardized gravimetrically'.Absorption spectrajwere recorded on a Bausch andLomb Spectronic 20 spectrophotometer. Polaro-graphic waves were recorded on a Herovyskypolarograph (LP 55A) which was operated manuallyin conjuction with a Pye scalamp galvanometer.The d.m.e, had the characteristics, m2/St1/6 = 1·759.IR spectra were recorded in KBr on a Beckmann IR20 spectrophotometer. Magnetic measurements werecarried out at room temperature (300 ± 1°) employingGouy's method. Mossbauer spectra were recordedon a spectrometer comprising a single channelanalyser and an electronic constant velocity loud-speaker drive, using 3 m Ci CO'7 in Pd matrixsource. The spectrometer was calibrated againstsodium nitroprusside and standard iron foil and thespectra were recorded at room temperature (200 ± 10).The complex was isolated by mixing equal volumesof O·lM solution of Fe (III) and Ka[Mn(CNhNO]and adding acetone. The green precipitate wasfiltered, washed successively with water, acetoneand ether and dried in vacuo over anhydrouscalcium chloride. The complex was decomposedwith HNO. and HCI to estimate Fe and Mn gravi-metrically'. Water of crystallization was deter-mined by desiccation at 1100 for 3 hr {Found: Fe,18·11; Mn, 17·82; C, 19·41; N, 22·65; HIO, 11·87.-Present address: Bundelkhand University, Jhansi.tTo whom all correspondence may be addressed.616Fe[Mn(CNhNO].2H.O requires Fe, 18'24; Mn, 17'91;C, 19·54; N, 22'80; H.O, 1l·72%}.The green-coloured soluble complex shows ab-sorption maxima at 380 nm (E = 700) while theparent compound I shows Amax at 220, 348 and 540nm, Vosburg and Cooper's method reveals theformation of only one complex species. A1:1 stoichiometry for the complex was establishedby the molar ratio and continuous variation methods.The stability constant of the complex as determinedby the molar ratio method works out to be 5·60 X10'. The value of -I1G was found to be 5·105 kcal/mole.KI[Mn(CN).NO] gives two reduction waves inKCIO,. The first wave is well defined and reversiblewith E1/2 = -0·305 V, while the second wave isirreversible and spread out with El/2 = -1·40V. Theelectrode process taking place at the d.m.e. has beensuggesteds-" to be:[MnI(CN),NO]3-+e--+[MnI(CN)••(NO)O]4-[Mnl(CN)II(NO)O]"'+e--+[MnI(CN),(NO)"]5-[MnI(CN),(NO)-]5--+[Mnl(CN)J(-+NO-The formation of [MnI(CN)i]6- has also been sup.ported by the work of Jacob8•However, o~ complexation with Fe (III) , thesecond wave disappears and only one well-defineddiffusion-controlled wave is obtained with a definit~shift in El/2 towards more negative potentials(Table 1). The wave is reversible, since the plots oflog i/i4-i versus Ed.e. are linear. There is only onewave due to the reduction of Fe(IU). After reactionwith Fe (III) , only the. cationic part, i.e, Fe(III), getsreduced at d.rn.e. while the cationic complex moietyhas no role to play in the reduction. Lingane'smethod was used to determine the formula andstability constant of the complexs, The stabilityconstant works out to be 5·0212 X105 which is inagreement with the value obtained by the spectro-photometric method.The IR spectra of the complex and the parentcompound Ks[Mn(CNhNO] were almost identicaland showed characteristic bands for lattice water(3300 and 1600 em-I), v,.C . N. (2100 em-I) and, v,NO (1800 crrr-). thus eliminating any fresh co-ordination with Fe(UI) in the complex. The loweringof the frequency of lattice water suggests somebridging involving OH groups. However thebridging OH grouplO,ll should show a band around1100 cnr+. Since no such band is observed sucha possibility is ruled out and the 3300 cm-l' bandmay be assigned to lattice water.TABLE 1- SHIFT IN E, IN INCREASING CONCENTRATIONOF K,(Mn(CNhNO){[Fe(III)) = 0·15 X lo-lM}K.[Mn(CN),NO] Etx 10"M V1-52·04·05·0-0·015-0·04-0,05-0,06Magnetic susceptibility of 5·81 BM correspondedto 5 unpaired electrons in the complex indicatingthat iron in the complex is ionic and in the oxidationstate +3.K.[Mn(CN)5NO].2H10 is diamagnetic. IRspectra and magnetic data, therefore, provide clearevidence that the nitro and the cyano groups arenot involved in the reaction with Fe (Ill) .The Mossbauer spectra of the complex showsisomer shift of 0·23 ± 0·02 mm/sec and a quadrupolesplitting of 0'65 ± 0·02 mm/sec. The value of isomershift and quadrupole splitting showl2 that iron isionic and in the trivalent state. The narrow lineshapes show that Fe is only in one valency state,i.e. +3. The unusually large value of quadrupolesplitting may be due to lattice distortionI3,a aroundFe ion as in the case of FeCla.6HsO.References1. BLANCHARD, A. A. & MOONSUN, F. S., J. Am. chem, Soc.,62 (1941), 2236.2. COTTON, F. A., MONCHAMP, R. R., HENRY, R. J. M. &YOUNG, R. C., J. inorg. nucl. Chem., 10 (1958), 28.3. MALIK, W. U., BEMBI, R. & VERMA, B. B., J. Radioanal.Cbem., 26 (1975), 287.4. JACOB, W., GOLEBIEWSKI, J., Theory, structure of complexcompounds (Paper Symposium, Wroclaw, Poland), 1962,381.5. VOGEL, A. I., Quantitative inorganic analysis (LongrnansGreen, New York), 1961.6. SIEKIERSKI, S. & SIEKIERSKI, E. K., Roczniki Chem., 30(1956), 339.7. SEN, B. K., GOSH, N. N. & SARKAR, P. B., J. Indian chem,Soc., 40 (1963), 815.8. JACOB, W. & SENKOWSKI, J., Rocmiki Chem., 38 (1964),1751; 40 (1965), 1601.9. LINGANE, J. J., Chem. Rev., 29 (1941), 1.10. SCARGILL, D., J. chem. Soc., (1961), 4440.11. NAKAMOTO, K., Infrared spectra of inorganic and cool'di-nation compounds (John Wiley, New York), 1963,159.12. GOLDANSKI, V. r. & HERBER, R. H., Chemical applica-tions of Miissbauer spectroscopy (Academic Press, NewYork), 1968.13. DANON, J., Rev. Mod. Phys., 36 (1964), 461.14. DANON, J., J. chem. Phys., 39 (1963), 263.Schiff Base Formation from CoordinatedDiamlne in Mixed Complexes ofCu(I1) & Ni(I1)P. C. PARIKH & P. K. BHATTACHARYAChemistry Department, Faculty of ScienceM.S. University, Baroda 390002Received 30 January 1975; accepted 14 October 1975Template synthesis of Schiff base complexes hasbeen attempted by the reaction of salicylaldehyde withthe mixed li~and complexes of the type [(L-LI-)M·l,3-diaminopropane], where L-LH. = catechol or 2,3-dihy-droxynaphthalene. The resultin~ mixed complexesretain (L-V-) moiety in their structure and the -OHgroups of the Schiff base N,N'-propylenebis(salicylaldi-mine) remain uncoordinated.IN a recent communication- we have used thetemplate method to react salicylaldehyde withethylenediamine and propylenediamine in mixedNOTESligand complexes of the type M.ALwhere 14= Cu(II)or Ni{Il), A = catechol or 2,3-dihydroxynaphthaleneand L = ethylene- or propylene-diamine. Twosalicylaldehyde molecules undergo condensation withthe two - NHt groups of the coordinated diaminesand because of steric reasons the resultant complexeshave a square-planar geometry where coordinationoccurs through the azornethine nitrogens and ligandA. It has been suggested earlier2,a that the Schiffbase may occupy two equatorial and two axialpositions if the length of the chain R in the diamineNHz-R-NH. is more. As such the compounds ofthe type MAL where M = Cu(II) or Ni(U), A =catechol or 2,3-dihydroxynaphthalene and L =1,3-diaminopropane have been prepared and theirreactions with salicylaldehyde studied.Methods of preparation - (i) Bis- or tris-(1,3-di-aminopropane)nickel(U) chloride (0'5 g) was dissolvedin the minimum quantity of water and aqueoussolution of catechol (1M) added to it. The pH ofthe resultant solution was ,...,6. On trituration andleaving the solution aside for 30 min, a bluish greencompound was obtained. It was washed with water,dried and analysed, (ii) To a mixture of equimolar(1M) aqueous solutions of nickel chloride andcatechol in 1:2 ratio, an aqueous solution of1,3-diaminopropane (1M) was added till PH was,...,6. On trituration and leaving the solution asidefor 30 min, a bluish green solid was obtained. Itwas washed with water, dried and analysed. Theanalysis of the compounds prepared by methods(i) and (ii) corresponds to the composition [Ni(cat)-(1,3-pn)J.2HaO. The same method was used forthe preparation of [Cu(cat)(l,3-pn)].2H.0. Similarmixed ligand complexes were also obtained when2,3-dihydroxynaphthalene was used instead ofcatechol. The analytical results are shown inTable 1.0·5 g of the diamine complex obtained above wasreacted with 10 ml of salicylaldehyde. The mixturewas refluxed on a water-bath for an hour. Thesolution was concentrated and excess of ether wasadded when a solid separated out. The compoundin each case was washed with ether to remove excessof salicylaldehyde and recrystallized from chloro-form. The compounds were found to be TLC pure(single spot). Co-TLC with Ni-SB indicated thatthe present complex is a mixed ligand complex ofthe type [MASB).The magnetic susceptibilities of the isolated com-plexes were determined by Gouy's method.The absorption spectra of the compounds I-IV(Table 1) have been studied in water and of thecompounds V to VIII (Table 2) in chloroform. Thespectra of the compounds were taken on a nU2Beckman spectrophotometer at room temperature(30°), using 1 ern quartz cell in the range of 300-1000nm,The analysis of compounds I-IV shows them tobe mixed ligand complexes. The water moleculesare lost at 120°. These may be coordinated or maybe water of crystallization.The visible spectra of the Cu(II) complexesexhibit a broad band at ,...,6S0 nm. The Cu(II}complexes may have a square-planar structure. In617

Polaroaraphic & Spectral Studies on the Reaction of Fe(III) with Pentacyanonitrosylmanganate

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Polaroaraphic & Spectral Studies on the Reaction of Fe(III) with Pentacyanonitrosylmanganate

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