Kohli, H. S.

Manhas, B. S.

Sandhu, S. S.

English

NOPR

Indian Journal of ChemistryVol. 14A, December 1976, pp. 991-993Complexes of Organic Arsonic Acids: Part IX - Complexes ofCr(lll) & Co(II) with- Arylarsonic AcidsS. S. S.-\.NDHU & B. S. MANHASDepartment of Chemistry, Guru Nanak Dev University, Amritsar 143005andH. S. KOHLI:'II.S.R.N. Government College for Women, AmritsarReceived 9 January 1976; accepted 21 April 1976Complexes of Cr(lll) and Co(lI) with aryl arsonic acids having the gener-al formula (X.C6H,ASO,(mM.nH20, have been isolated [when M = Cr(III), m = 1·5 and n = 2, 2·5, 4 or 5; whenM = Co(II), m = 1 and n = 0·5, 1 or 1·5; X = H, P-CH3' p-CI, p-Br, P-OCH3' o-OCH3, o-COOHor o-NOz]. The complexes have been characterized on the basis of elemental analysis, magneticmoment and IR and reflectance spectral studies. The As03 group of dibasic arylarsonic acidsacts as a tridentate li~and in all the complexes and o-carboxyphenylarsonic acid behavesas a tetradentate Ilgand. On the basis of hi~h rneltmg points and insolubility in commonorganic solvents, a polymeric structure seems probable for these complexes. In most of theCo(II) complexes, the unusual Ier-rornagnettc character is indicated by the magnetic susceptibilitymeasurements at different temperatures. Distorted octahedral structures are proposed forboth Cr(IlI) and Co(II) complexes.IN continuation O.f our studies 0:1 arYlar.solicacids8-16, complexes of Cr(III) 1.'1d Co(II)with phenylarso..ic acid (A) a i d its d·,riva.-tives; (B) p-methyl-, (C) p-chloro-, (D) p-bromo-,(E) p-methoxy-, (F) o-methoxy-, (G) o-carboxy-a-id (H) o-nitrophenylarso.iic acids l13.Vl; beenisolated ald characterized. Cr(III) forms thermallystable basic polym .rs with arsinic a-id phosphinicadds, wlrich are useful a., a I .icorrosive ad1l',re'ltsl.Co(II) complexes with m :rhylar;o iic acid>, c-amino-phenylarso llC aci(13, p1l'olylarsoic acid- aid Schiffb3.scs5,6 1l1.VI·lg Aj03H2 '~rolp; a:11 a mixed liga'ldcomplex? of Co(II) contai :ing urea aid p:v.:'lylarsolicacid have also been reported.Materials and MethodsArvlarsouc a:ids were prepared by the reportedmethodsI7-I9.Cr(HI) complexes were prepared by refluxingaqueous solution of chrorninmfl H) acetate andetha-iolic solution of the required acid for 30 min.Co(H) complexes were obtai led by adding cobalt-(II) acetate to the boil ing solutio-: of the required acidin absolute ethaiol a id refluxing till the precipitatesettled down, The complexes were purified bywashing the precipitate repeatedly with hot etha-ioland drying in vacuo.Chromium was estimated by treating the complexwith CO:JC. H2SOj and igniting it i'l air to CrZO:1.Cobalt was determined volumetrically by t itrationwith EDTA. The a'lalysis for C, H, N a-id halogensand magnetic aud IR and reflecta-ice spectral studieswere carried out as reported earlierw.Results and DiscussionThe results of elemental a'lalyses (Table 1)suggest that the complexes may be represented bythe general formula (X.C6Hl.AsOa)m.lv1.nHp. Whenl\I = Cr(III), tn = 1'5 and n = 2, 2'5, 4 or 5 forM = Co(II), lit = 1 and n = 0'5, 1 or 1'5. Forboth the series X = H, P-C03, p-Cl, p-Br, P-OCH3'o-OCR3, o-COOR or o-NOz.Due to insolubility of the complexes in commonorga'lic solvents the measurements of conductivitya.id determination of molecular weights could notbe carried out. Insolubility of the complexes alongwith their high melting points suggests that thecomplexes are probably polymeric.Various IR baids (in cm-I) due to -AS03R2 groupin the spectra of arylarso.iic acids are assigned asfollows2o-22: vOR, 2750 a'ld2250; VAs-C(aromatic),1125-1077; vAs = 0; 935-845 (however, in acids (B), (C)a.id (D) it splits into a doublet); VasAs(g. 860-785and vsAs(g, 790-755. The absence of the bandsdue to -OR groups i:l the spectra of the complexessuggests the coordination of metal iO:1S throughoxygen of the As03 group. This is further supportedby the shift (-55 to +70 cm-I) in the posit ions ofsymmetric a-id asymmetric stretching frequenciesof As(g-group 0:1 complex formation. The vAs = 0shifts downward by 35-50 em? in Cr(III) complexesof acid (E) and the Co(II) complexes of acids (B),(D) and (H). In all the complexes of Cr(III), exceptthat of acid (E) and Co(II) complexes of acids (F)and (G), the downward shifted (by 10-105 cnr")vAs = 0 band overlaps with the band due toasymmetric stretch of As(g. In Co(II) complexesof acids (C) aud (E), the downward shifted (by 95and 65 cm! respectively) vAs = 0 bands overlapwith the band due to phenyl ring. The downward991INDIAN J. CHEM., VOL. 14A, DECEMBER 1976TABLE 1 - ANALYTICALAND ROOMTEMPERATUREMAGNETICMOMENTDATA OF THE COMPLEXESComplex" Calc. (%) Found (%) !LeffC H Metal C H(BM)Metal(CeH.As03)1'SCr.2H2O 27-84 2·96 13·4 28·06 3-45 13·3 3-62(P-CHa·CeH,As03)1·.Cr.2·5H2O 30·14 3·70 12·4 30·05 3·87 12·3 3·73(p-Br.CsH,As03)1·SCr.2Hp 21·32 1'97 11·0 20·70 1·96 11'2 3·83(P-Cl.CsH,As03)1·SCr.4H2O 22'70 2·94 10·9 22·43 2'52 11·2 3'57(P-OCHa· C6H6As03h .5Cr.2· SH20 28'50 3'50 11'8 28'44 3-70 11·6 3·83(o-OCH3·CsH,As03)1·SCr.4H2O 26·86 3·94 11-1 26·94 3·80 11'2 3·83(o-COOH.CeH.As03)1·SCr.5H2O 24·80 3·44 10·2 24·73 3-69 10·3 4·36(o-N02·CsH,As03)1·SCr.2Hp 23·71 2·19 23-87 2·19 3-44p-CH3·C.H,As03Co:0·5H2O 29·80 2·84 20·9 29·76 2·87 20'6 5·11p-Cl.C.H.As03Co.H2O 23·11 1·93 18·9 23·59 2·28 19·2 5·19p-Br.C.H.As03Co.0· 5H2O 20·75 1·45 17·0 21·02 1·96 17'2 5·46p-OCH3CsH.As03Co.0· 5H2O 28·19 2·69 19·8 28·00 2·99 19·4 4·94o-OCH3·C.H.As03Co.H2O 27·36 2·93 19·2 27'61 3·31 19·5 5·22o-COOH.CsH.As03Co.l· 5H2O 25·46 2'43 17·9 25·54 2·56 18·1 4'97o-N02·CeH.As03Co.H2O 22·36 1·86 18·3 22·68 1·75 18·5 5-41·Satisfactory analyses for halogens were also obtained.shjft in As = 0 bands may be ascribed to the bondingof metal ions to the As = 0 oxygen. This con-clusion is corroborated by a small shift in the \lAs-C(aromatic) on complex formation. Hence As03group of the acids acts as a tridentate ligand in allthe complexes.The analytical data coupled with IH. studies showthat proton of carboxylic acid group remains intactin the complexes of o"carboxyphenylarsonic acid.However the doublet at 1650, 1637 CIn-1 assignedto \lC = 0 in the acid shifts to 1590 and ]580 crrr"in Cr(III) and Co(II) complexes respectively indicat-ing the coordination of C = 0 oxygen to the metalions-", The small change in the position of bandsdue to substituted groups of the acids in complexesmay be due to change in the environment.The room temperature magnetic moments of allthe Cr(III) complexes except that with o-carboxy-phenyl arsonic acid lie in the range 3,44-3,83 El\Iwhich correspond to tn« spin-only value (3·87BM) for three unpaired electrons. The reflectancespectral data of all tn« complexes show tn« presenceof bands in the regions 24,400-22,200 and 16,700-16,400 ern? and also intense broad bands ill theregions 44,000-42,000 and 38,000- 35,000 crrr '. Theintensity, shape and energy of the observed bandsshow that the first two bands may be due to d-dtransitions whi le the other 1\"0 may be attributedto charge-transfer. Assuming an octahedral stereo-chemistry around Cr(III) the first two bands maybe assigned= to the transitions 4TIg(F)~_3A2g(F)and 4Tu(F)<f:-4A2g(F) respectively. The values ofDq and B calculated-" on tile basis of these observedbands are 1640 and 559·7 crrr ' respectively. Onthe basis of these values of Dq and B, the calculatedvalues for the two-electron transition, 4Tl&(P)<f:-4A2g(F) , comes out to be 35,393 crrr '. Due to thepresence of an intense charge-transfer band in thisregion, this weak band is not observed. Theobserved magnetic moment value of 4·30 EM inthe case of o-carboxyphenylarsonate is a little higherthan tnose repo rted'" for octahedral complexes b~tthe presence of bands at 22,700 and 16,400 em'? 1Il992TABLE 2 - MAG!,;ETICSCSCEPTJBILITJESOF Co(II)COMPLEXESAT DIFFERE!,;T TEMPERATURESTemp. [lcff(K) (B:\I)o value. Temp. !Leff(1\:) lDI6 values831051311652202935·585·305'355·335·255·11801081311632152955·385·255·185·105·014·94+15 +16p-Cl.C.H,As03·Co.H,O82 5·34 82 5·31106 5·33 97 5·31129 5·30 107 5·34163 5·26 +9 130 5·34 0213 5·18 162 5·34293 5·1l) 213 5·27296 5·22p-Br.C.H,As03·Co.0·5H,O871031261612162945·575·525·475·535·445·4680971161612122924·584·604·684·824·884·97+3 -21its reflectance spectrum indicates distorted octa-hedral structure for the Cr(III) complex witho-carboxyph en y la rson ate.The room temperature magnetic moment valuesof the Co(II) complexes SllOW the presence of orbitalcon tributior, expected for octahedral species. Thestudy of magnetic susceptibilities of Co(II) complexesat different temperatures (80-293°K) is quite interest-ing (Table 2). Contrary to the usual behaviour ofoctahedral Co(II) complexes, the magnetic momentsof the present cobalt(II) complexes with acids (B)to (G) decrease with increase in temperatures", Thisbehaviour may be attributed to the presence ofSANDHU et al.: Cr(III) & CollI) COMPLEXES WITH ARYLARSONIC ACIDSferromagnetic interaction ill the complexes. InCo (II) complex of o-carboxyphenylarsonic acid the-COOR group is coordinated to the central metalion and thus ferromagnetic interaction may not bepossible ill this complex. Tne reflectance spectraof the Co(lI) complexes SllOW the presence of twostrong bands in the regions 7700-7550 and 18500-18200 crrr? and a weak band in tne region 16450-16150 crrr", Thus on the basis of magnetic andreflectance studiesss, a distorted octahedral struc-ture is proposed for Co(II) complexes. The valuesof Dq and B, nave bet 11 calculated= and arc ir: theranges 875-860 ard 802-769 ern respectively. Thesevalues almost correspond to the values iu, = 830em? and B = 845 em-I) for the octahedral phenyl-phosphon ate-cobalt (II) found by GrinOll])eau28 andcoworkers. Thus phenylphosphenic acid and aryl-arsonic acids havo almost equal ligar d field strengthsand ncphelauxctic effects.Ac knowledg erne ntTnanks are due to Prof. B. Venkataraman, TIFR,Bombay, for providing facilities for magnetic sus-ceptibility measurements at different temperatures.References1. BLOCK, B. P., GILLMAl\;. H. D., GRZYMALA, P. :'II. &I\JAl\;NELLI, 1'. L., ci.-« Absir., 76 (1972), 114975w.2. GILIET, ]., HUYGE-TIPRLZ, G., KIeoLE, ]. 8: TRIDOT, G.,C.r. Acad. su. Sf}. C. 273 (1971), 1743.3. MASLENNIKOVA, 1. S. & SHEMYAKIN, V. N., Zh.fiz. Khim.,46 (1972), 10044. SANDHU, S. S. & SANDHU, G. K., Indian .f. Chem., 9(1971), 885.5. BASATO, 1\1. & PELOSO, A., Gaze. chim. ital., 101 (1971),281.6. SANDHU, S. S. & SANDHU, G. K., Indian j. Cheni., 12(1974), 830.7. MALIK, A. G. & KHAN, 1\1. M., j. inorg. nucl, Chem., 35(1973), 247.8. SANDHU, S. S. & SANDHU, G. K., J. inorg. nucl . Chem.,34 (1972), 2249.9. SANDHU, S. S. 8: AULAKH, G. S., Indian]. Chem., 11(1973), 46.10. SANDHU, S. S., KOHLI, H. S. & MAKHAS, B.S., IndianJ. ci-»: 11 (1973), 197.11. SANDHi', S. S. & At'LAKH, G. 5., Indian]. cu«, 13(1975), 28l.12. SAl\;DHt', S. S., KAUR, J. & SANDHi:, G. K., Syn. React.inorg, metalorg. Chem., 4 (1974), 437.13. SANDHU, S. S. & AlTAKH, G. S., Indian]. Chem., 13(1975), 518.14. SANDHl", S. S. 8: 1\1EHTA, A. K., Indian J. Chem., 13(1975), 733.15. SAl\;DHV, S. S., ::VIA:-iHAS,B. S. & KOHLI, H. 5., IndianJ. Chem., (accepted).16. SANDEl'. S. S., SANDHU, C. K., l\IANHAS, 13. S. & KOHLI,H. S., Indian ]. CIII'1I1 .. (accepted).17. VOGFL, A. I., Pructical organic chemistry (Longmans,Green, London), 1962, 617.18. PALMER, C. S. 8: ADAMS, R,.f. Ain. chem. Soc., 44 (1922),1369.19. BLTCKE, F. F. & WEBSTER, G. L., J. Am. chem,Soc., 59 (1937), 534.20. HENRY, M. c.. Lnorg . ci-«, 1 (1962), 917.21. Bx anos, T . .T., DATTA-GUPTA, N. & HEBBORN, P., J.mrdnl Cheni .• 9 (1966). 221.22. DIETZE, G., J. prakt. Chem., 313 (1971), 889.23. TAYLOR, 1\1. D., CARTER, C. P. & \VYNTER, C. 1., J. inorg:nucl, ci-«, 30 (1968), 1503.24. LEVER, A. 13. P., Inorganic electronic spectroscopy (Else-vier, New York), 1968, 275, 320.25. FIGGIS, 13. K., Introduction to ligand fields (Interscience,New York), 1964, 167.26. KONIG, E., LINDNER, E., LORENZ, 1. P., RITTER, G.& GAFSMANN, H., J. inorg. nucl. Chem., 33 (1971),3305.27. FIGGIS, 13. K. & KYHOUI, R. S., J. chem, Soc., (1959),338.28. GRINO:-iNEAF, W. C., CHAPMAN, P. L., MENKE, A. G.& \VALMSLEY, F., J. inorg, n ucl, ci-«, 33 (1971).3011.993

Complexes of Organic Arsonic Acids: Part IX - Complexes of Cr(III) & Co(II) with- Arylarsonic Acids

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Complexes of Organic Arsonic Acids: Part IX - Complexes of Cr(III) & Co(II) with- Arylarsonic Acids

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