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Title: STUDIES ON THE METAL COMPLEXES OF ANILIC ACIDS
Authors: Arya, Ram Singh
Keywords: CHEMISTRY;ANILIC ACIDS;ANILIC ACID ENTROPY;ANILIC ACID ENTHALPY
Issue Date: 1983
Abstract: The organic compounds containing - GOOH and -CGNH-- as coordinating sites have been found very useful from analytical, medicinal, biological, agricultural and industrial point of view. Therefore, anilic acids were choosen to be used as ligands and their metal complexes with transition metal ions have been studied. The present report comprises of the detail on the metal complexes of the following ligandss (i) Maleauilie acid and its ^-methyl, ^-methoxy, !f-chloro, *t--.bromo, *+-nitro arid 1-napnthyl derivatives. (ii) Phthalanilic acid and its ^methyl, ^--methoxy, ^-chloro, ^bromo, U-nitro and 1-naphthyl derivatives. The studies were planned merely to look into the structure and analytical behaviour of their metal complexes. A major portion of the investigation is devoted to the determination of coraoosition, stability and tiermodynamical parameters of the complexes in the solution form. But whenever it has been possible to isolate the complexes in the solid form, their structural analysis has been done by various methods such as IR, electronic spectra, magnetic and conductivity measurements and chemical analysis. Mossbauer spectroscopic studies have also been carried out in the case of iron(III) complexes. The present thesis has been divided into three sections, viz., A,B and C. Section - A This section comprises of three chapters. Chapter -1 This chapter deals with the determination of proton-liga.id dissociation constants of rnaleanilic and phthalanilic acids and their derivatives, pi and p 2 values corresponding to the deprotonation of -CO0H and -CONR respectively are given. The order of pxV2 values for rnaleanilic (M) acid derivatives is as follows? ^--methoxy M> ^-methyl M> M> ^-bromo M 3 ^f-chloro M > M-nitro M The same order of p 2 values was also found in the case of phthalani lic acid derivatives. The liberation of proton from secondary 1 amido group (-CONH ) is affected by both inductive as well as mesomeric effect of the substituents. Chapter -2 This chapter describes the determination of thermodynamical constants for the interaction of anilic acids with bivalent transition metal ions. The order of stabilities in most of the cases has been found as, MrfH) < Co(ll) < Bi(II) < Cu(ll) > Zn(II) < Fe(ll). The higher value of Fe(II) and Cu(II) complexes may be attributed to the higher crystal field stabilization energy and Jabx-Teller effect respectively. The contraction energy RrCMn-Zn) obtained around 205.10 + 1.38 '&3 mole"1 and the heat of complexation (AH,) indicated the coordination through nitrogen and carboxylic ii oxygen atom. This observation was confirmed by the analysis of thermodynamical data i.e. the values of enthalpy and entropy (iii) changes. The trend obtained in the case of stability constants is also observed in t;ie Values of AS and Ail and hence it appears that the stability of the complexes was mainly due to aS values which are large and positive. The higher values of entropy changes (aS) may be due to the negative charge on the coordinating sites which brings about a shielding of central dipositive metal ion from exercising its orienting influence on the unfrozen distant water dipoles. Chapter -3 This chapter deals with the determination of thermodynamical constants for the interaction of anilic acids with lanthanide( III) T ions. There is a regular increase in the values of log Tu from lanthanum to holmium except gadolinium. Fairly large values of AS and negative values of all indicate that rnaleanilic and phthalanilic acids and their derivative? are bonded to the metal ions through nitrogen of secondary amido and oxygen of carboxylate group. The decrease in the entropy change for the second and third step reactions may be attributed to the statistical effects which axe also reflected in the values of AG and stepwise stability constants Ah values for the second and third step reactions are less negative which may be a result of water molecules getting closer to the metal or of a stronger metal-ligand interaction. (iv) Section - 3 This section comprises of two chapters. Chapter -1 In this chapter the results of studies on complexes of Cu(Il), Ni(II), Co(II) and Pd(II) with phthalanilic and rnaleanilic acids and their derivatives have been incorporated. The complexes of the type [Cu(P)2].2u2o, [CuU)2].2H2C, Oi(P)2(ri20)2], [M( M) g< E^) g] , [Co(P)2(H20)2], [Co(M)2(H20)2], [Pd(P)2] and [Pd(M)2l where P a deprotonated phthalanilic acids, M= deprotonated rnaleanilic acids, could be isolated in the solid form, analysed chemically and characterized on the basis of conductance, magnetic, IR and electronic spectral studies. The complexes of copoer(II) and palladiumC II) were found to be square-planar while that of nickel(II) and cobalt(II) were octahedral. Chapter - 2 In this chapter the results of studies on complexes of Cr(III) and Fe(III) with anilic acids are embodied. The complexes of the type [Cr(P) ], [Cr(M) ], Ka£F«(P)2( 0H)2] and Na[Fe(M)2(0H)21 where ? = deprotonated phthalanilic acids, M = deprotonated rnaleanilic acids, were prepared in the solid form and analysed chemically. The non-electrolytic nature of Cr(III) complex s and bi~electrolytie nature of Fe(III) complexes was confirmed by carrying out their conductance measurements. The values of magnetic moments (3-72 - 3.78 B.M.) for chromium(III) complexes, presence of three bands in their electronic ppeetra ranging 16000 - 17200 cm" (X), (v) 22200-23500 cm"1 (V2) and 36IOO-376OO cm"1 (K) and the values of B, p^ and the percentage deviations (oV2,)0 between the calculated arid observed values ranging Q.$k _ l.o5, confirmed their octahedral structure. The values of magnetic moments (5.82 - 6.0- fi.M.) indicated the formation of high spin complexes of iron(III). The electronic spectra and the values of isomer shifts and quadri pole splitting indicated the presence of iron(III) in octahedral environment. Sectuon - C This section also comprises of two chapters. Chapter - 1 This chapter has been devoted to the. studies on the amperometric determination of thorium( IV) with rnaleanilic arid phthalanilic acids and their derivatives which have been found highly selective and also provides not only a rapid arid accurate method but have the advantages of less interfering also. Th(IV) has been determined at an applied e.m.f. -1.2V (dme VS SCE) with maleacilic acids and -1.0V (dme VS SGL) with phthalanilic acid- in the range 6.60 - 2350.0 mg/100 ml and 12.0 - 1160.0 mg/100 ml respectively with an error of + 0.2 to + 0.3 percent. This method has also been used for the determination of Tn(IV) in monazite sand. Chapter - 2 This chapter describes the spectrophotometry determination of iron(III) with 2-methoxy phthalanilic acid. The determinations (vi) were carried out at 500 nm end in the pH ranp;e 2.5 - 3-0- r^Cie confirmity of Beer's law was studied arid the optimum concentration range for 1 cm cell was found to be k.O - 16.0 ppm of iron(III). The complex was formed in the ratio of 1:3 (M;L) and the stability 12 constant of the complex was obtained to be 3.77x10 . The inter ferences caused by various cations and anions have also been reported The reagent was found to be sensitive arid less interfering.
URI: http://hdl.handle.net/123456789/1141
Other Identifiers: Ph.D
Research Supervisor/ Guide: Sharma, C. L.
metadata.dc.type: Doctoral Thesis
Appears in Collections:DOCTORAL THESES (chemistry)

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