Bhasin, S. K.

Bhat, A. N.

English

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INDIAN J. CHEM., VOL. 14A, DECE;\lBER 19765'0 &-A SnCI3(OC6H5)·C6HSOH versus C6H50NO.-. Ti(OC6HS)4- .C6HSOH versus C6H50NoQt-8 SnCI310C6HS)'C6H50H versus_ 40 ()-()Ti(OC6H5)4·C6H50H versus'E-"IEs:o"'-'~ 30x•."c2":::J1i! 2-0ou.~•..'u•.it 1·00'4 0'8 1·6 2·0 2'4 2-8 3·21·2Molar ratio Basel AcidFig. 1- Conductometric titrations between acids and basesin phenol at 50°other tertiary bases with phenol follow a similarpattern (unpublished data).Strong acceptor molecules such as antimonypentachloride, boron trichloride, aluminium trichlo-ride, etc., readily get solvolysed in fused phenol at45°. In the case of tetrachlorides of tin andtitanium, partially solvolysed products of composi-tionSnCI3(OC6H,,).C6HsOHand TiCI3(OC6Hs),C6HsOHare obtained. Complete solvclvsis of these com-pounds has been carried out to get Sn(OC6Hs)4 andTi(OCeH5l4,C6HsOH respectively (unpublished data).Acid-base t itrat ions of SnCi3(OC6H5),C6H50Hagainst C6H50Na or C5H5~ have been carried out.These t itrations have been iollowe.l both conducto-metrically and with the help of visual indicatorssuch as malachit e green anti crystal violet (Fig. 1).There are two breaks in the conductance-compositioncurves (Fig. 1) suggesting the dibasic character ofthe acid. Similarly tit rations of Ti(OC9H5)~.CeHsOHagainst pyridine or sodium phenoxide have alsobeen carried out. Compounds of compositionNa2Ti (OC6H5)6 and Ti(OC6H5)4.2CsH5~ have beenisolated from the solutions. Compounds of similarnature have already been reported in the case ofalkoxides13,14. The titrations apparently followreactions (1), (2) and (3).2C6HsOH'" +M(OCeH5)~- +Na+ +OC6HS-+CeHsOH~'" +NaM(OCeH5)&+2CeHsOH ... (1)CeH50Hi+ NaM(OCeHs)6+Na+ +OC6H5-+~a2[M(OCeR5)6J +2CeHsOH (2)Na2[M(OCeH6)6J~2Na+ +M(OC6H5H- (3)By analogy with the behaviour of methyl alcohol-sand acetic acidl6-18 and in the light of above observa-1018tions, the possible mode of ionization of phenol maybe postulated as2C6HsOH~C6H50H;+C6H50-References1. HARROD, J. F. & TAYLOR, K. R., Inorg. Chem., 14 (1975),1541.2. BIRD, P., FRASAR, A. R. & LAU, C. F., l norg, Chem., 12(1973), 1324.3. :'>lALHOTRA,K. c.. :\lAHAJA~, R. K. & CHAUDHRY, S. C.,J. inorg, uucl, Chem., (communicated).4. BIRCHALL, T., BOURxs, A. N., GILLESPIE, R. T. & S~ITH,P. J., Can. j. cio«, 43 (1964). 1433.5. PARRI~GTON, B. D. & CHILD, R. F., Chem, Comrnun.,(1970), 1581-6. BLACKSTOCK, S. :'II., RICHARD. K. E. & WRIGHT, G. J.,Can. j. Chem., 52 (1974), 331-7. MALHOTRA, K. C. 8: BALI, A. K., Indian J. Cliem., 13(1975). 699.8. GREENWOOD, N. N. & WADE, K., J. chem, Soc., (1958),1671.9. PA1:L, R. c., PA1:L, K. K. & :'>fALHOTRA,K. c., ChernyInd. (London), (1968), 1227.10. PAUL, R. C. & CHADHA, S. L., Spectroctrim, Acta, 22(1966), 615.11. CORDES, A. W. & HUGHES, T. V., l norg, Chem., 3 (1964),1640.12. HUNSHUGER, H., J. Am. chem, Soc., 72 (1950), 5626.13. MEHROTRA, R. C. & :'IIEHROTRA, A., Inorg, ci.«, 11(1972), 2170.14. PAUL, R. c., :'IIADAS, H. & CHADHA, S. L., J. inorg,nucl. Chem., 36 (1974), 737.1S. LUDMAN, C. J. & WADDINGTO:-:, T. c., J. chem. Soc.,(1966), 1816.16. PAUL, R. C., \'.~SISHT, S. K., 1\1.~LH9TRA, K. C. & PAHIL,S. S., .f. scient. indo Res., 21B (1962), 552.17. PAUL, R. c., YASISHT, S. K., :'>1.~LHOTRA,S. K. & PAHIL,S. S., A n al . Chem., 34 (1962), 820.18. PAUL, R. C., KAPOOR, K. R. & PAHIL, S. S., J. scient.indo Res., 21B (1962), 533.Co(II) Complexes of Pyridine-2-aldoxime &6-Methylpyridine-2- aldoximeS. K. BIIASIS & A. X. BHATDepartment of Chemistrv, Univcrsitv of Delhi, Delhi 110007Received 19] aiiuary 1976; accepted 26 April 1976The reaction in acetone of GoGI2.H20 with pyridine-2-aldoxime (HPOX) and 6-methylpyridine-2-aldoxime(HMePOX) in different stoichiometric ratios (1 : 2 andI : 3) in the absence and presence of hydrogen peroxidehas yielded different Go(lI) complexes. One of these,viz, Go(HPOX).GI2 is identical with that reportedearlier in literature [Aust. J. Chern., 27 (1974). 2475].The IR studies on these complexes indicate that in somecases, one ligand is ionized and the other unionizedwhereas in some cases both the Iigands in the complexesare unionized. All the complexes are cationic. Themeasured high magnetic moments rule out +3oxidation state of the metal ion in any of these COm-plexes.THE ligands pyridine-2-aldoxime (HPOX) and its6-methyl derivative (HMePOX) are usefulanalytical reagents':". Stability constants of theircomplexes with trivalent lanthanon ions have beenreported" and complexes of HPOX with Ni(II),Pt(II) , Pd(II)7,9 and CU(II)10,11 have also beeninvestigated. The Co(II) complex of HPOX wasformulated as Co(HPOXh.2HzO.Cl2 (ref. 12) but onreinvestigation was fOW1d to be Co (HPOXhC12(ref. 13).The present communication deals with prepara-tion and characterization of the different Co(II)complexes of HPOX and HMePOX.HPOX and HMePOX [F. Raschig GmbH (Lud-wigshafen)J were used after crystallization fromwater and ethanol respectively. CoC12.6HzO andacetone were of AR (BDH) grade. Cobalt wasestimated by the standard gravimetric procedure-s,A strong cation exchange resin 4765 (I~. Merck)and anion exchanger IR-45 (OH) (Rohm & Hass)were used.Magnetic measurements were determined on solidsamples using Gouy type balance. HgCo(SCN)4was used as the standard.Preparation of the complexes - Cobalt chloridehexahydrate (0·01 mole) dissolved in boiling acetone(40 ml) was added to a solution containing stoichio-metric quantity of the ligand (0·02 mole) in acetone(20 mI). The mixture was refluxed for 2 hr whenthe red complex precipitated out. It was filtered,washed repeatedly with hot acetone and dried invacuo oyer P205 at 110° for 3 hr. The green com-plexes were obtained from similar mixtures whichhad been refluxed in the presence of 30% H202(15 ml). The following complexes (A to E) wereobtained:(A) CO(C6H6N20)CL!, red, m.p. 2250 (Found: C,39·5; H, 3·5; N, 14·7; Co, 14·9. Calc.: C, 3S'5; H,3·2; N, 14·9; Co, 15·7%).(B) Co(C6H5N20)(C6H6NzO)C1.2I:£20, green, m.p.200° (Found: C. 38·8; H, 3·5; I\, 14·0; Co, 14·9.Calc.: C, 38·56; H, 3'48; N, 14·9; Co, 15·7%).(C) Co(C7H8~ zO)zCI2, reel, m.p. 2300 (Found: C,41-1; H, 4·1; .-, 13·7; Co, 13·~. Calc.: C, 41·8; H,4·0; N, 13-9; Co, 14·1%).(0) Co(C7H7~20)(C7H8N20)CI.2H20, green, m.p.165° (Found: C, 41·9; H, 4·0; N, 13·5; Co, 13·4.Calc.: C, 4H3; H. 4·7; N, 13·9; Co, 14·6%).(E) Co(C7H8N20lsCI2.H,p, green, m.p. 2220(Found: C, 45·5; H, 4·4; N, 14·9; Co, 10·9. Calc.:C, 45·3; H, 4·6; N, 15·1; Co, 10·6(10)'The complexes A, E, C and E also resulted fromthe reaction mixtures containing three moles of theligand per mole of the metal ion.The compounds isolated in the absence of HzOzare red while those obtained in its presence aregreen in colour. All of them are crystalline, quitestable and sparingly soluble in water (0·002M solu-tions can be prepared), nitrobenzene and otherpolar organic solvents, but insoluble in non-polarsolvents.The coloured aqueous solutions of the complexes(0·002M) were passed through the cation exchangeresin. The eluant obtained was colourless and con-tained Cl ions in each case thereby indicating thatthe complex ion involved is a cationic species. Thecomplexes when passed through the anion exchangergave eluants of the same colour.Magnetic moments of the complexes were foundto be generally high in all the cases. The valueswere 4·4 (B), 4·6 (C) and 4·2 BM (E). These areNOTESclose to the value of 4·65 reported earlier for (A).These values, although high, are within the rangeof Co(II) complexes having 3 unpaired electrons,and definitely rule out a +3 oxidation state for themetal ion.The assignment of the bands in the IR spectra*(KBr) of the complexes have been made on thebasis of Krause et al.9 and Holmes et al.15 for themetal chelates of HPOX. On the basis of assign-ments made earlier for metal-nitrogen ligand com-plexes'"-!". the band at 480-490 crrr" in the com-plexes is assigned to vCo-N and the one at 415-305em? to vN-Co-N (ref. 18). The spectra of theacetylated products of complexes (A) and (C) showednew strong absorption bands at 1740 cm! ascribableto a free carbonyl group (-COCH.). No bandswere, however, observed for the vOH ill the 3000em? region. This is in accordance with the spectradiscussed for the acetylated products of Cu(II) andBe (II) with ~-resorcylaldoximes19.The water of crystallization in (B), (D) and(E) was inferred from the bands at 3550-3400crrr".On the basis of the IR studies it has been possibleto conclude that while in the case of (A), (C) and(E) the ligands are present in their unionized form,in the case of (B) and (0) one of the ligand moietyis present in the ionized form.One of us (S.K.B.) thanks the CSIR, New Delhi,for the grant of a senior research fellowship.References1. BRAT, A. K & JAIN. B. D.. J. scient. indo Res., 21B(1962), 576.2. GAGLIARDI, E. & PRESINGER. P., Cheni. Abstr., 63 (1965)17132d. '3. PFLACM. A. T.. WEHKING. M. \Y. & JENSEN. R. E., Tala-nta,8 (1964), 1193.4. KV~!AR. N .. MANKU, G. S., BRAT, A. . & JAIN, B. D.,Talanta, 17 (1970), 873.5. BHAT, A. ~. & JAIN, B. D., Pl'OC. Indian Acad. Sci., 56A(1962), 285.6. KUMAR. N .. MANKU, G. S., BRAT. A. N. & JAIN, B. D.,J. less-common Metals. 21 (1970). 23.7. KRAUSE. R. A. & BeSCH, D. x., Nature, 181 (1958)1529. '8. KRAUSE, R. A. & BUSCH. D. K. ]. Am. chem, Soc., 82(1960), 4830.9. KRAUSE, R. A.. COLTHUP. K B. & BUSCH. D. N., J. phys.Chem., 65 (1961), 2216.10. LIt:, C. N. & LIU, C. F., J. Am. chem . Soc., 23 (1961),4169.11. FAUCHERRE, J. & PETITFOUX, c., Bull. Soc. chim, Fr.,(1965), 347.12. BLACKMORE, M. ,V. & MAGEE, R. ]., Aust, J. Chem.,20 (1967), 429.13. GRANT. M. W. & l\fAGEE, R. J., Aust. ]. cu«; 27(1974). 2475.14. VOGEL, A. 1., A text book of quantitative inorganicanalysis (Longmans Green & Co. Lt.d, London), 1961,529.15. HOLMES. F .. LESS, G. & UNDERHILL, A. E., J. chem.Soc., (A) (1971}, 999.16. KATRITZKY. A. R.. Q. Rev .. 13 (1959), 252.17. POWELL, D. B. & SHEPPARD. N., J. chem. Soc., (1956),3108.18. SHIMANOUCRI. T. & NAKAGAWA, I .• Spectrocliim. Acta,18 (1962), 89.19. BHASIN, S. K., UMAPATHY, P. & SEN. D. N., Indian].Chem., 8 (1970), 744.*Detailed IR data can be had from the authors onrequest.1019

Co(II) Complexes of Pyridine-2-aldoxime & 6-Methylpyridine-2-aldoxime

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Co(II) Complexes of Pyridine-2-aldoxime & 6-Methylpyridine-2-aldoxime

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