Agarwala, U.

Nigam, P. C.

Pandey, G. C.

Pandey, G. S.

English

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JDdiaa ,Jounaal of ChemistryVoL IU, Nonmber 1976. pp. 884-887Complexes of Ag(I), Cu(I), TICI), Zn(II), Cd(II), Hg(II), Hg(I),Pd(o) & Pt(o) with z-Thioorotic AcidG. S. PANDEY·. G. C. PANDEYt, p, C, NIGAM: & U. AGARWAL.-\.Department of Chemistry. Indian Institute of Technology, Kanpur 208016Received 18 December 1975; accepted 24 Apri! 1976Ai(l), Cu(I), Zn(II), TI(I), Cd(II), HI1(I),H~(II), Pd(O) and Pt(O) complexes of 2-thioorotic acidhave been prepared and characterized on the basis of analytical and IR data. The complexesare insoluble in common oriantc and inorl1antc solvents Indtcatlng their polymeric nature.Probable 8tructures have been assil1ned on the basis of IR data.IN continuation of our earlier workl-3 we reporthere preparation and characterization of thecomplexes of Ag(l), Cu(I), Zn(II), Tl(I), Cd(II),Hg(II), Hg(I), Pd(O) and Pt(O) with 2-thioorotic acid.Materials and MethodsThe chemicals used were of AR or CP grade.2-Thioorotic acid (I) (abbreviated as H2tot) wasprepared by the method described in literaturev".Ammonium salt of 1 (abbreviated AmHtot) wasprepared by dissolving 1 in the minimum amount ofhot liquor ammonia and evaporating the solution todryness. The white residue was recrystallized anddried at 110°. Sodium salt of the ligand (NaHtot)was prepared by the same procedure as that ofammonium salt except that sodium bicarbonatewas added in place of NH40H. The deuteratedligand in the acid form was prepared by refluxing0·1 g of (I) in 25 ml D~O for about 24 hr while astream of Nz gas was bubbled through the suspension.The residue was separated by centrifugation anddried in vacuo overnight and finally in an oven at110° for 4 hr. The deuterated form of the sodiumsalt of the ligand (NaHtot) was prepared by a similarprocedure.Preparation 0/ the complexes: (2-Thioorotato)-silver(I)- A solution of AgN03 (0·4 g, 2 mmoles) inwater (25 ml) was added to a neutral solution (25 ml)of AmHtot (0·4 g, 2 mmoles), A pale yellow complexwas immediately formed. To this suspension, 1 mlof dil. HNOs (1: 5) was added, the reaction mixture-thoroughly stirred and digested on a water-bath for1 hr, when a yellow compound was obtained. It wasseparated by centrifugation, washed repeatedlywith water and dried at 110°. The method of pre-paration of the deuterated complex was exactly thesame except that DzO and NaHtot were used inplace of H20 and AmHtot.(2-Thioorotato)thallate(I)- An aqueous solution(30 ml) of Tl2S04 (1 g, 2 mmoles) was added to a·Present address: Department of Chemistry, Govt. Collegeof Engg & Tech., Raipur.[Present address: Department cf Chemistry, BhagalpurUniversity, Bhagalpur.:To whom all correspondence should be addressed,solution of AmHtot (0·2 g, 1 mmole) in water (50 ml]and the resulting mixture digested for 30 min to get awhite precipitate. It was centrifuged, washed re-peatedly with water and dried at 110°. The deu-terated species of the complex was prepared byexactly the same procedure as above except thatNaHtot and DzO were used in place of AmHtotand H20.(2-Thioorotato)dithallate(!)- The ligand (0·2 g,1 mrnole) was dissolved in excess NH40H and boiledto obtain 50 ml of a clear ammoniacal solution. Ahot solution of TlZS04 (1 g, 2 mmoles) in water (50 ml)was added to this ammoniacal solution when alight-yellow compound was immediately precipitated.The mixture was digested on a water-bath for 30 min,the precipitate centrifuged, washed repeatedly withhot water and dried at 110°.Ammonium (2-thioorotato)cuprate(I)- A solutionof the freshly prepared cuprous chloride (0·4 gCuCl2 + 50 ml water + copper foil was kept over-night) in 50 ml of NH40H was added to a solution ofAmHtot (0·4 g, 2 mmoles) in water (25 ml). Thiswas digested on a water-bath for 1 hr when a redprecipitate separated. It was centrifuged, washedrepeatedly with water and dried at 110°.Ammonium (2-thioorotato)dicuprate(I) - CuzCl2(0·2 g, 1 mmole) and H2tot (0·2 g, 1 mmole) were.dissolved separately in NH10H and then mixed.The reaction mixture was di ': sted on a water-bath for1 hr. A dark brown precipitate was obtained whichwas centrifuged, washed thoroughly with hot waterand dried at 110°C.Ammonium ietraaquoiris (2-thioorotato )dizincate(I I)- A solution of ZnCI~ (0·3 g, 2 mmoles) in water(25 ml) was added to a solution of AmHtot (0·8. g,4 mnoles) in warm water (50 ml). The reactionmixture was digested for 10 min when an yellowish-white compound separated. It was centrifuged,washed repeatedly with hot water and dried at 1100•The deuterated complex was obtained by refluxingabout 0·2 g of the complex in 25 ml D20 for 2 hr.The residue was centrifuged and dried at 110°.Ammonium tetraaq uotris (2-thioorotato )dicadmitUe-(lJ) and its deuterated complex were prepared bya similar procedure as described for Zn(II) complexes.PANDEY et al.: COMPLEXES OF 2-THIOOROTIC ACIDBis(2-thioorotato)mercury(IJ)- HgCl2 (0·6 g) wasdissolved in a solution of Am(Htot) (0,8 g) in water(80 ml). It was digested on a water-bath for 1 hrwhen a white compound was obtained in colloidalform. It was stirred with dil. HCI (5 ml), allowedto settle, centrifuged, washed repeatedly with hotwater and dried at 110°. The deuterated complexwas prepared exactly in the same manner except thatNaHtot (0·8 g, 4 mmoles)was used in place of AmHtotin D20 (20 ml).Tris-(2-thioorotato)tetramercury(I)-Hg l(NOs)J(l· 7g,3 mmoles) was dissolved in 100 ml of hot dil. HN03(1: 10). On adding a warm solution of AmHtot(0·6 g, 3 mmoles) in 50 ml water, a grey-white preci-pitate was immediately formed. It was digested for30 min on a water-bath. The precipitate was cen-trifuged, washed repeatedly with hot water and driedat 110°.(2-Thioorotic acid) (triphenylphosphine)dipyridinepalladium(O)- Tetrakis(triphenylphosphine) Pd(O)(0·6 g, 0·5 mmole) prepared by the method of Coalson'was added to boiling benzene (50 ml) through whichN2 was continuously bubbled. A clear yellowsolution resulted to which was added slowly a solu-tion of Hjtot (0·4 g, 2 mmoles) in pyridine (20 ml).The resulting solution was refluxed for 1 hr, when agreyish-white complex precipitated. It was centri-fuged, washed repeatedly with benzene, ethanol andether and dried in vacuo.(2-Thioorotic acid) (triphenylphosphine)pyridineplatinum(OJ- Tetrakis(triphenylphosphine) plati-num(O) was prepared by the method of Malatestaand Cariello", The procedure for the preparation ofPtL(PPhs)(py) (L=H2tot) was similar to that usedfor PdL(PPhs(pY)J except that Pt(PPhs)( (0·7 g,0·5 mmole) was used in place of Pd(PPhs)4' Thecomplex formed was white in colour.Results and DiscussionThe results of analysis are given in Table 1. Thediamagnetic behaviour of the present complexes andthe absence of any band in the visible region oftheir electronic spectra confirm that the metal ionsin the complexes belong to d10 or pseudo-s'" system.These complexes are insoluble in most of the in-organic and organic solvents which could be due totheir polymeric nature.The IR spectra of the ligand and its deuteroderivatives were discussed earlier'. As a result ofcoordination, shifts are expected in the positions ofthe characteristic bands due to COO-, thioamideand amide groups which are the possible bondingsites. The complexes reported here have beenclassified into groups based on the directions of theshifts in the major IR band positions.Ag(Htot), Tl(Htot) and Hg(tOt)2- IR bands insimilar positions (± 5 crrr") were observed for thesecomplexes. the bands due to vO-H and vO-Dat 3600 and 2500 em? present in the spectra of theligand and the deuterated ligand respectively dis-appeared in the spectra of the complexes and theirdeutero derivatives indicating coordination throughcarboxylic group. The band due to vN-H wasobserved at 3200 cm+. This band shifted to2300 cm-I on deuteration of the complexes. Inaddition, on deuteration two new bands at 970 and1070 crrr? appeared due to 3N-D indicating that boththe N-H groups are present in the complexes. Theamide bands-I, -IV and -VI at 1680, 680, 620 cm-1respectively and the band due to "N-H at 720 cm-1observed in the spectrum of the ligand were notshifted in the spectra of the complexes. Thioamidebands-III and -IV at 1030 and 940 em+ respectivelyin the ligand were shifted to lower wave numbersTABLE 1- ANALYTICALDATA OF THE COMPLEXES*Complexes Analysis, Calc. (Found), (%)C H N S MAg(C5HaN,OsS) 21-6 1-1 10·0 11-4 38·7(21-1) (1,2) (10'0) (11'6) (38'2)NH.[Cu.(HN.OsS)] 23-8 204 16·6 12·7 25-2(24-1) (2-6) (17-1) (12,8) (25'6)NH.[Cu.(C,NHa03S)] 19'0 1·6 13·3 10·1 40·2(18,8) (1'6) (12'9) (9,7) (40'7)Tl.(C,H.N.O.S) 10·0 0·8 4·8 5·5 70·5(9·8) (0·9) (4-8) (5·5) (70·0)Tl (CsH.N.Os S) 16·0 0·6 7·4 8·5 54·6(16,5) (1,0) (704) (8-4) (55·0)NH.[Zn.(C.H,N .0.S).(C,H.N.osS)].4 H.O 24·6 2-6 13-4 13-1 17·7(25,1) (2'1) (13,1) (12'7) (17·2)NH.[Cd,(C,H2N.OaSh(C,HsN.osS)].4H.o 21·8 2·1 11·9 11·6 27·2(22,3) (1·8) (1204) (12·0) (27,7)Hg(C,H.N .0sS). 22-1 1·1 10·3 11·7 36·9(12-1) (36'3)Hg[Hg.(C,HsN .OaS)3~ 13·7 0·6 6·4 7·3 61·0(7·4) (60'5)Pd(C.H.N.O.S)P(C.H.)s(C.H.N). 55·7 4-1 8·0 4·6 15·2(55,2) (4,2) (707) (4,1) (14·8)Pt(C,H.N,OsS)P(C.H.l3(C,H.N) 47·5 3-4 5·9 4·5 27·5(48·0) (3·0) (6-4) (4,2) (27'6).•Analyses were carried out by standard methods"-ll.8~INDIAN J. CHEM .• VOL. 14A. NOVEMBER 1976in the spectra of the complexes. indicating ~etalion interaction with the C=S group. The positionsof the thioamide bands-I and -II changed onlyslightly in the spectra. of t~e complexes ~ith slightbroadening of the thioamide band-I which couldhave been expected if the metal is bonded to C=Sgroup. Two new bands appeared around 450 and350 em? which may be assigned to vM-O and vM-Srespectively. All these shifts are compatible withthe linear structure (A) for these complexes.. Tl2(tot)- The bands due to vN-H and ~N-H at3200 and 720 cm-l respectively were relatively lessintense than those found in the spectra of the ligandand TI(Htot) indicating that at l~ast one N~. re-mains uncoordinated. On deuteration, the POSItIonsof the bands shifted to 2300 and 580 em? res-pectively. The bands due to vOH disappearedindicating coordination through COOH group. Thepositions of the amide bands-I, -IV and -VI wereshifted to 1630. 660 and 600 crrr- respectively in thespectrum of the complex. On deuteration, thepositions of these bands remained unchanged. Inthe spectrum of the deuterated T12(tot), only one newband appeared at 970 crrr-. The band at 1070 crrr-due to 8N-D of the thioamide group disappeared.This indicates that the proton of the thioamide groupwas deprotonated on complex formation, while thatof the amide group remained intact. New bandsappeared in the region 500-350 em+ which may beassigned to coupled modes of vibration due to vTl:O,vTI-N and vTl-S. The positions of the thioarnidebands-III and -IV were not shifted. In deuteratedcomplex also, these positions remained unchanged.All these shifts are in keeping with the structure (B)for this complex.NHtCu(tot) - The band positions in the spectrumof this complex were similar to those in the TI2(tot)spectrum except that the bands due to [NH41+ ionwere present around 3200. 1700 and 1450 crrr+. Ifit would have been an ammine complex, a bandaround 800 crrr? should have been present due tocoordinated NH3. Therefore. it is assumed that thecomplex contains an ammonium ion, rather thancoordinated NH2 group. A structure similar to thatof TI2(tot) is assumed for the complex.NHljMs(totMHtot).4H20 (M =Zn or Cd) - Thespectra of these complexes were similar to that ofNH(Cu(tot) except for the following differences:The spectra contained all the bands (though rela-tively less intense) present in the spectrum ofAm(Htot). The shifts in the positions of thesebands on deuteration were similar to those observedfor deuterated AmHtot. The characteristic bandsdue to coordinated water were present around 3440,1600. and 850 cm+. Their positions were shifted to2500, 1055 and 600 crrr- respectively on deuteration.The bands due to COO- group were present around1650 and 1400 cm+. The structure (C) with o,symmetry is assumed for these complexes. .The presence of all the IR bands of AmHtot Inthe complexes of Zn and Cd indicates a double saltstructure where AmHtot is crystallized along with themetal complex. It is also possible that there mightbe an interaction of the carbonyl group of (AmHtot)with the metal ions in place of one H20 molecule. In:886C::-,O-MI~OH-C~C""'N-HI 1o=c C=S-MNIH(AI I BIM=AgIII, TI( I lor Hg(II)OH2O~c/O'-........ I /OH2 I1 M ~cH, .....c..../"" I<,o~"c...... NI I OH2OH OH2 ~C'N""C~S2", I/0 IM H<,N/I <,OH2I 0" ~O~ IC IM=ZnllIl or cerm- +O~C/O NH4..... ICu" C~ HN "C .I I~C •.....•. C~S N ~O./ I "-/Cu Cu CuI "-rD.)that case. bands due to amide groups should shift.Generally, the shift is proportional to the degree ofinteraction. In case the interaction is not large.shifts will not be appreciable and cannot be detectedby IR spectra. However, we prefer the structure(C) for these complexes.NH,Cu2(tot) - The IR spectrum of this complexalso showed bands due to ammonium ions around3300, 1600 and 1460 crrr". But for the presence ofthese bands, the rest of the spectrum was similarto one of the cleuterated silver complex except forthe following differences.The bands due to N-D group present in the spectrumof silver complex were not present in this spectrum.The position of the amide bands-I, -IV and -VIwere shifted to 1600, 660, and 600 crrr" respectively.It is, therefore, inferred that in the complex allthe protons have been substituted by either ammo-nium ion or Cu(I) ion, and copper ion interacts withC=O of the amide group and C=S of the thioamidegroup. The tentative structure (D) is assigned forthe complex.Complexes of Pd(O) and Pt(O)- The spectra ofthese complexes were very complicated. However.all the bands due to pyridine. triphenylphosphineand H2tot were present in the spectra of thesecomplexes with their positions slightly displaced.The thioamide bands-III and -IV were shifted tolower wave numbers [1010 and 920 em? in Pt(O)complex, and 1010 crrr+ in Pd(O) complex]. Be-..PANDEY et al.: COMPLEXES OF 2-THIOOROTIC ACID•sides this, the positions of the amide bands-IV and-VI were shifted to 660 and 600 crrr" which was notthe case in the spectrum of Pd(O)complex. Hence itappears that Pt in its complex is coordinated through>C=S and >C=O groups while Pd is coordinatedthrough thiocarbonyl sulphur only.Hg[Hg3(HtothJ - The spectrum of this complexwas very complicated and no definite inferencecould be deduced from the spectrum except thatthe positions of the bands due to COOH groupwere shifted to lower wave numbers indicatingbonding through COO- group. In order to satisfythe charge balance one of the N-H should also bedeprotonated and form link with Hg.References1. PANDEY. G. S., NIGAM. P. C. & AGARWALA, D.• J. inorg,nucl. Chem., (communicated).2. PANDEY. G. S., NIGAM, P. C. & AGARWALA, D., Aust. J.Chem. (communicated).3. PANDEY. G. S., NIGAM. P. C. & AGARWALA, D., Can. J.Chetn, (communicated).4. JOHNSON, T. B. & SCHROEDER, E. F., J. Am. chem. Soc., 53(1931). 1989.5. JOHNSON. T. B. & CRETCHAR, J. Am. chem, Soc., 37(1931), 2144.6. JOHNSON, T. B. & SCHROEDER, F.. J. Am. chem. Soc.,54 (1932), 2941.7. Inorganic synthesis. Vol. 13, edited by D. R. Coulson(McGraw-Hill, New York), 1972, 121.8. MALATESTA, L. & CARIELLO, c., J. chem. Soc., (1958),2323.9. TREADWELL. F. P. & HALL, W. T., Analytical chemistry,Vol. II (John Wiley, New York), 1958. 199.10. VOGEL. A. 1., A text book of quantitative inorganic analy-sis (Longmans Green. London), 1961, 389, 390, 483,486. 498, 51L 549, 574.11. BEAMISH. F. E., The analytical chemistry of the nabl«metals. Vol. 24 (Pergamon Press. Oxford), 1966, 308,314.887

Complexes of Ag(I), Cu(I), TI(I), Zn(II), Cd(II), Hg(II), Hg(I), Pd(o) & Pt(o) with 2-Thioorotic Acid

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Complexes of Ag(I), Cu(I), TI(I), Zn(II), Cd(II), Hg(II), Hg(I), Pd(o) & Pt(o) with 2-Thioorotic Acid

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