Dara, S. S.

Deshpande, V. D.

English

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pectively and TOH is the concentration of the baseadded to the reaction mixture during the titration,that under the condition T M = T A = T L·_ TM--'::X[L-]KMAL - X[L-P ... (3)where X=[H+]+l andkl[L-] = (2-m)T~'I-[H+]+[OH+J[H+J/k1where kl is the dissociation constant of the secondaryligand.Formation. constants of the hydroxo derivative of1: 1: 1 mixed ligand chelaies - A gradual increasein the values of log KMAL at m>1·8; 1'5, 1·32, 1'36;1·56, 1·40 and 1·64 in the case of Ni(II)-bipy-gly,ala or norleu; Zn(II)-bipy-gly, ala or norleu ; Cd(II)-bipy-gly, ala or norleu probably indicates that theaddition of the hydroxyl groups starts before thecomplete formation of 1: 1: 1 mixed ligand chelateresulting in the formation of a hydroxo derivative.The equilibria involved in the formation of mono-hydroxo derivative of 1: 1: 1 mixed ligand chelatemay be represented byMAL++OH-~MAL(OH) ... (4)and the overall formation constant KMAL(OH) ofthe monohvdroxo derivative In these systemsmay be defined as:[MAL(OH)JKMAL(OH) = [MA2+][L-j[OH-] ... (5)Other pertinent equations are:TM=' [MA2+]+ [MAUl + [MAL(OH)) ... (6)TOH+[H+]-T A -[OH-] = [MAL+]+2[MAL(OH)J+[L-] (7)TL=[MAU] +[MAL(OH)]+[HLJ +[L-] (8)Eliminating [MAL(OH)] from Eqs. (6)-(8) andrearranging the terms, we obtaina[MA2+J2+b[MA2+J-c = 0 •.. (9)2[1-1-'-]where a = KMAL, b =T +1 and c ={(3-m)T :'.1- [H+]+ [OH-]}X.The equilibrium concentration of MA2+ presentin the reaction mixture may be obtained by solvingEq. (9) and the concentrations of other speciesinvolved in the equilibrium relations can then becalculated from the above equations and also thevalue of formation constant, KMAL(OH)'The values of the formation constants of themixed ligand chelate KMAL and its monohydroxoderivative KMAL(OH) are presented in Table 1. Theformation constants of rnonohydroxo derivativeof Ni(II)-hipy-gly, Ni(Hj-bipy-ala, Ni(II)-bipy-norleu, Zn(II)-bipy-ala and Zn(II)-bipy-norieu couldnot be calculated, as the precipitation occurs atan early stage after the addition of hydroxyl groupstarts.The order of stability of mixed complexes in termsof metal ions is: Ni(II) >Zn(II) >Cd(II) as expectedfrom Mellor and Maley order. Further, the orderof stability in terms of secondary ligands has beenfound to be: glyc-alac-norleu and this can be ex-NOTE STABJ·E 1 - FOR~fATION CONSTANTS OF MIXED LIGANDCHELATE AND MONOHYDROXO DERIVATIV'ES· .tern log KMAL log KMAL(OH)Ni(IJ\-bipy-glyNi(I"; -bipy-alaNiC ./-oipy-norleuZn(lI)-bipy-glyZn(II)-bipy-alaZn{II)-bipy-norleuCd(II)-bipy-glyCd(II)-bipy-alaCdff Il-bipy-norleu5·50±0·035·15-1-0·074-90±0'094·67±0·044·32±0·13Hl±0·123·97±0·123·72±0·U3·64±0·089·90±0·048·06±0·078·04±0·077'92±0'12plained on the basis of the enlargement of the chainin ec-alanine and norleucine svstems.Thanks are due to Prof. K~ C. Joshi, ChemistryDepartment, University of Rajasthan, Jaipur, forproviding laboratory facilities and the authoritiesof J. V. College, Baraut (Meerut), for encouragement.References1. BLAU, F., ee«; 21 (1888), 1077.2. BLAU, F., Mh. cu«, 19 (1898), 647.3. BRANDT, W., DWYER, F. P. & GYARFAS, E. C., Chem. Rev.,54 (1954), 959.4. CHATT, J., J. inorg, nucl. Chem., 8 (1958), 515.5. PANIMON, F., HORWITT, M. K. & GERARD, R. W., J.cellular Physiol., 17 (1941), 17.6. CHABEREK, S. (Jr) & MARTELL, A. E., J. Am. chem, Soc.,74 (1952), 5052.7. YAMASAKI, K. & YASHUDA, M., J. Am. chem, Soc., 78(1956), 1324.8. KEEFER, R. M., J. Am. chem: Soc., 68 (1946), 2329.Mixed Ligand Complexes of Lanthanides withDiacetylmonoxime as a Primary Ligand &N-Substituted Anthranilic Acids as SecondaryLigandsV. D. DESHPANDE & S. S. DARADepartment of ChemistryVisvesvaraya Regional College of Engineering, Nagpur 440011Received 12 July 1976; revised 6 January 1977;accepted 24 April 1977Mixed complexes of lanthanide ions Y3+,La'+, Prs+,Nds+, Sm3+, G~'+, Dy3+ with diacetyhnonoxime asprimary ligand and N-phenylanthranilic acid and N-methylanthranilic acid as secondary Iigands have beensynthesized and characterized on the basis of analytical,spectral and thermal data.SEVERAL simple lanthanide complexes withvarious oximes have been reported and cha-racterized-". Mixed ligand complexes of lanthanideshave also received much interest in recent years6-9•Mixed complexes of lanthanides using oximes asprimary ligands and 1,1O-phenanthroline, oxineand pyridinc-Z-aldoxime as the secondary ligandshave also been reported-v. Preparation and cha-racterization of several mixed complexes of lantha-nides using DAMO as the primary ligand and NPAAand NMAAll as the secondary ligands are reportedin this note.839INDIAN J. CHEM., VOL. 15A, SEPTEMBER 1977Lanthanide diacetylmonoximates were preparedby the method of Rao et al.s from specpure lantha-nide oxides and reagent grade diacetylmonsxime.The mixed complexes were prepared adopr=ig thefollowing procedure:Lanthanide diacetylmonoximate (LnDA~'Cl3'4H20, 200 mg) was dissolved in ethanol~" ml)and mixed with calculated amount (mole ratio c.: 3)of the N-phenyl or N-rnethyl anthranilic acids;these acids were prepared by literature method-",The pH of the solution was adjusted to 5·8 by theaddition of alcoholic ammonia. The resulting solu-tion was evaporated on a steam bath and the solidobtained washed with ether to remove excess ligand;yield 75%. All the compounds were dried in vacuoover fused calcium chloride for 48 hr. Analvticaldata are given in Table 1. -In their UV spectra DAMO exhibits a band at,.....,220nm (log E 4·04), NPAA at 290 nm (log E 4'28)and NMAA at 220 (log E 4·65) and 255 nm (log E 4·13).The bands around 220 and 255 nm could be dueto 71:-3>-71:*and around 290 nm be due to 11-3>-71:*transitions. In the several lanthanide mixed com-plexes both the characteristic band maxima ofprimary and secondary ligands have been observedwith slight shift in their positions and change inintensity. The log E values in the complexes areof the order of 4·92-5,17. This observation givesan indication that both the ligands are attachedto the metal ion.Characteristic bands of Pr3+ could not be locatedin the mixed complexes reported in this note.Among the Nd3+ complex only Nd3+ DAMO-NPAAshowed a band around 470-490 nm (log € 2·82).The characteristic band of Sm3+ ion around 402nrn is also absent in the mixed complexes. Sucha disappearance of lanthanide ion bands in theirmixed complexes has been reportedw, The dis-appearance of the bands, as a first approximation,can be taken as an evidence of strong complexbeing formed.In the IR spectra (KBr) of the complexes ofY3+, La3+ and Pr3+ with DAMO and NPAA thevOH and vNH overlap and appear at lower fre-quency (3300-3320 cm-'). In the case of Nd3+,Sm3+, Gd3+ and Dy3+ these bands are shifted toa slightly higher frequency (3400 crrr-). The',1(=0 band at 1655 in DAMO and at 1650 crrr!in NPAA disappear in all the complexes exceptin La3+ and Pr3+ where they are located at 1605and 1645 crrr? respectively. These changes indicatethat the C=O groups of both the ligands are involvedin bond formation. The changes observed in theother groups such as C=C phenyl, C=C phenylconjugated, substituted phenyl, COOH and C6H5NHare in conformity with the observations made inlanthanide Nvphenylanthranilatestt. The 975 crrr+band due to ',IN--0 of oxime could not be locatedin these complexes.In the mixed complexes of Pr3+, Nd3+ and Sm3+with DAMO and NMAA vOH (3350 cnr-) and vNH(3375 crn<) of DAMO and NMAA respectivelyappear as broad split band slightly shifted to lowerfrequency region (3360-3340 crrr-). Only broaden-ing is observed in Gd3+ and Dy3+ complexes. ThevC=O of both the Iigands (1650 crrr+) appear at840TABLE 1 - ANALYTICAL DATA OF THE COMPLEXESCompound M (%) N (%)Calc. Found Calc. FoundY(DAMO),(NPAA). 10·75 10·6 6·77 6·20La(DAMO),(NPAA). 15·86 15·17 6·39 6·33Pr(DAMO),(NPAA). 16·04 15·75 6·378 6·1N d(DAMO), (NP AAls 16·36 16·20 6·35 6·20Sm(DAMO), (NPAA)3 16·94 16·70 6·31 6·26Gd(DAMO),(NPAAlo 17'58 17·48 6·26 5·9Dy(DAMO),(NPAA)3 18·06 18·00 6'22 6·05Pr(DAMO),(NMAA). 20·35 19·91 8·09 8·03Nd(DAMO),(NMAA). 20·74 20'42 8·05 8·00Sm(DAMO),(NMAA)3 21·44 21·28 7·98 7·94Gd(DAMO),(NMAAls 22·20 21·7 7·907 7·51Dy(DAMO),(NMAA). 22·17 22·12 7·85 7·62DAMO = diacetylmonoxime; NPAA = Nvphenylanthrani-lie acid; NMAA = N-methylanthranilic acid.TABLE 2 - THERMAL BEHAVIOUR OF SAMARIUM DIACETYL-MONOXIME AND ITS MIXED COMPLEX WITH N-PHENYL-ANTHRANILIC ACIDTemp.°CWeight loss (%) Probable composition ofthe residue140340520580Theor. ExptlSm(DAMO),Cl.4H,O16 Sm(DAMO),Cl.30 Sm(DAMO),C1.40 SmCI.56 Sm,O.16·7428·4940'2358·75260360460520820Sm(DA:\W),(NPAA)311 Sm(DAMO),(NPAA)2!33 Sm(DAMO),(NPAAht50 Sm(DAMO),(NPAA),56 Sm(NPAA),80 Sm20.11·9535·8347·2358·9680·09lower frequency (1620 crrr+) suggesting involvementof C=O group in bond formation.NMAA exhibits bands at 1440 and 1240 crrr'!due to COOH group. The 1440 crrr+ band is absent, in Pr3+, Gd3+ complexes while it is lowered in Nd3+,Sm3+ and Dy3+ complexes. The 1240 crrr" bandis shifted to higher frequency and located around1280 crrr ' in the complexes. Similar effect on thisband is observed in DMG-NPAA mixed complexes'<.The anilino (1575 crrr") and the phenyl group (1510cm+) frequencies are slightly shifted. The vN-Oof DAMO could not be isolated in these mixedcomplexes.Thermal analysis of samarium diacetyl monoximeindicates the dehydration at 140° and confirmsthat the compound is a tetrahydrate. There isan endothermic peak at 3400 corresponding to aloss of 30% on TGA curve. This corresponds toa loss of half a molecule of DAMO. However,the complete removal of DAMO is observed at520° leading to the formation of sesquioxide at900°. Thermal study of mixed complex givesinteresting results. By comparison of weight lossesat 260° One can postulate the following two routesfor decomposition:(i) Sm(DAMO)1(NPAA)3-3>-Sm(DAMO)1(NPAA)2!-3>-Sm(DAMOh(NP AAht-3>-Sm(DAMOMN PAAh-3>-Sm(NPAAh-3>-Sm20S(ii) Sm(DAl\IO)l(NPAAh-+Sm(NPAAk~Sm(NPAA)2 -+ Sm(NPAAhi -> Slll(NPAAh -+Sm203From comparison of the thermal analysis ofsimple LnDAMO and LnNPAA complexes-- withthose of their mixed complexes it can be concludedthat the mode of decomposition of the mixed com-plexes follows the first route postulated. Thethermal data are detailed in Table 2.The authors express their gratitude to Dr R K.Shrivastava, Director, J. B. Research Institute,Wardha, for providing facilities to record the elec-tronic spectra, to Dr Y. R Rao for IR spectra, toDr V . .M. Dokras, Principal, V.RC.E., for providingresearch facilities and to Dr V. RamachandraRao of our department for his help during thecourse of this investigation.References1. RADHAKRISHNAMURTY, P. & RAYlACHA~DRARAO, V.,Chem. Abstr., 67 (1967), 58998b.2. RADHAKRISHNAMURTY, P. & RAMACHANDRARAO, V.,Curro Sci., 36 (J 967), 233.3. RADHAKRISHNAMURTY, P. & RAMACHANDRARAo, V.,Indian J. Chem., 6 (1968). 465.4. GALGALI,V. H., RAMACHANDRARAo, V. & KHANOLKAR,D. D., Indian J. Chem., 7 (1964), 825.5. TAKALKAR, P. V. & RAMACHANDRARAO, V., J. inorg.nucl. Chem., 37 (1975), 2103.6. DUTTA, N. K. & UPADHAYA,S., J. inorg. nucl. Chem.,28 (1966), 2719.7. DUTTA, X. K. & UPADHAYA,S., J. inorg. nucl, cue-«,29 (1967), 1368.8. HART, F. A. & LAMING, F. P., J. inorg. nucl. Chem.,26 (1964), 579.9. ROHATGl,K. K. & SENGUPTA,S. K, J. inorg. nucl. Chem.,32 (1970), 2247.10. VASIREDDI, S. P., Studies on rare earth complexes, Ph.D.thesis, Nagpur University, Nagpur, 1975.11. :\IANN, F. G. & SAUNDERS,The practical organic chemistry(Long mans, Green, London)' 1967, 215, 220, 371.12. PATIL, B. K, Ph.D. Thesis, Marathwada University,Aurangabad, 1974.13. DESHPANDE, V. D., Studies on lanthanide complexes,Ph.D. thesis, Nagpur University, Nagpur, 1975.Mixed Ligand Complexes of Sc(III), Y(I1I),La(I1I), Nd(I1I) & Sm(I1I) with EDTA asPrimary Ligand & Catechol-3,5-disulphonicAcid (Tiron) as Secondary LigandSANTOSHD. MAKHl]ANI* & S.HENDRA P. SANGALtLaxminarayan Institute of Technology, Nagpur UniversityNagpurReceived 14 June 1976; revised 16 August 1976;accepted 2 May 1976Stability constants of the mixed ligand complexes,MAL, where M=Sc(III), Y(III), La(III), Pr(III), Nd(III)or Sm(III); A=ethylenediaminetetraacetic acid(EDT A); and L=catechol-3,5-disulphonic acid havebeen determined at 30° and 11=0'2M (NaClO.> using amodified form of Irwing-Rossotti pH-titration tech-nique. In all the cases, stabilities of the ternary com-plexes are found to be less than those of the correspond-*Present address: National Environmental EngineeringResearch Institute, Nehru Marg, Nagpur 440020.tAuthor to whom correspondence should be addressed.NOTESIng binary complexes. The stability constants in-crease with decrease in ionic radii for binary as well asternary complexes.THE role of catechol-3,5-disulphonic acid (Tiron)as a secondary ligand in mixed ligand complexesof many metal ions>" has been extensively investi-gated. We report here the results of our studieson the mixed ligand complexes of Sc(IlI), Y(IIl),La(IIl), Pr(III), Nd(III) and Sm(III) with EDTAas the primary ligand and catechol-3,5-disulphonicacid as the secondary ligand. The stability constantsof the binary and ternary complexes have beendetermined using the Irving-RossottipH-titrationtschniquet, as modified for the mixed complexes.All the chemicals used were of AR grade. Rareearth perchlorates were prepared from the corres-ponding oxidess-" and standardised by comp1exo-metric methods-". The following solutions weretitrated against CO2-free 1·26M NaOH. The titra-tions were carried out under No atmosphere. Thetotal volume in each case wa~- 100 ml and ionicstrength was 0·2M (NaCIO~).(i) 0·02M ECIOd-O·18M NaCI04(ii) 0·02.JII HCIOdO·006M tiron+0·174M NaCI04(iii) 0·02M HC104+O'006Jl tiron+0·002M metalsalt +0, 1722\-1NaCl04(iv) 0·02M HCI04+O·002.M EDTA+O·002M metalsa1t+0'176M NaCl04(v) 0·02AI HC104+O·002M EDTA-I-0·002M metalsalt+0·006M tiron+0·170M NaCl04The" practical ,. proton-ligand stability constantsobtained using half n values method were log Kr=12·60 and log Kr=' 7·59. The metal-ligand stabilityconstants of the binary complexes were determinedas reported earlier+" by plotting n against pL.In all the cases, the value of n exceeded 1·5, whichreveals the formation of 1: 1 as well as 1: 2 com-plexes. The values of stepwise stability constantsfor the binary complexes as obtained by half n valuemethod are given in Table 1.Mixed ligand stability constants -- The primarycomplexation of rare earth with EDTA takes placeat a very low pH and the complex remains stableeven in the higher pH range.To prove the existence of mixed ligand complexformation, a composite curve was drawn assumingthat there was no mixed complex formation, andonly species present during the titration were 1: 1M(EDTA) and the free secondary ligand. Thiscomposite curve was compared with the experi-mental mixed ligand complex curve.TABLE 1 - STEPWISE STABILITY CONSTANTSOF BINARYCOMPLEXESAT300 AND f,L=0'2M (NaCIO.)Metal log Kl log K2 log (jSc(III) 17·78 9·32 27-10Y(III) 14·20 8·75 22·95La(III) 12·65 4·40 17·05Pr(III) 13·40 4·95 18·35Nd(I1I) 13.50 4·98 18·48Sm(III) 14-15 5·90 20·05841

Mixed Ligand Complexes of Lanthanides with Diacetylmonoxime as a Primary Ligand & N-Substituted Anthranilic Acids as Secondary Ligands

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Mixed Ligand Complexes of Lanthanides with Diacetylmonoxime as a Primary Ligand & N-Substituted Anthranilic Acids as Secondary Ligands

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