Indian Journal of Chemistry Vol. 29A, October 1990, pp. 982-985

Preparation and characterization of par~toluenesulphonato complexes of arsenicrlll), antimonyilll) and bismuthilll)

Pratibba Kapoor", Foonam Wadbawan & Sunita Tuli Department of Chemistry, Panjab University, Chandigarh 160014 Received 2 January 1990; revised and accepted 26 March 1990

Antimonylllf] oxide reacts with para-toluenesulphonic acid, ~CH3C6H4S03H(PTS), and its anhy- dride, (~H3C6H4S02hO, to yield SbO(~CH3C6H4S03) while bismuthflll) oxide combines with PTS and its anhydride to give BiO(~CH3C6H4S03) and Bi(p-CH3C6H.S03h, respectively. Arsen- ic(ill) oxide, however, shows no reactivity either towards PTS or its anhydride. Compounds of the. type M(~CH3C6H4S03h (M = As, Sb and Bi) have been prepared by the metathetical reaction be- tween silver para-toluenesulphonate and the appropriate metal chloride. Sodium arsenite and bis- muthate react with PTS to yield Na[AsO(~CH3C6H.S03hl and Na[Bi(~H3C6H4S03)41, respect- ively. The compounds have been characterized by elemental analysis, conductance and IR measure- ment. M(~CH3C6H4S03h (M = As, Sb, and Bi) compounds are capable of functioning both as lewis acids and bases. The para-toluenesulphonate ion in these compounds is easily replaced by Br " ion.

In an earlier paper), we have reported the prepar- tion of acid anhydride, (p-CH3C6H4S02hO to this ation, properties and characterization of methane- acid caused no further decrease in the conductiv- sulphonato complexes of As(III), Sb(III), and ity even when the two were allowed to equilibrate Bi(III). The analogous M(S03Xh salts [M = Sb(m) for several hours. The pure acid is a dark, highly and Bi(Ill) and X = F and CF3] have also been re- viscous liquid and has density equal to 1.2605 g ported in the hterature/". This paper describes cm-3 and surface tension equal to 20.14 dynes the preparation and characterisation of MO(p- em -e I at 35°C. CH3C6H4S03) [M = Sb(Ill) and Bi(Ill)], M(p- CH3C6H4S03h [M = As(Ill), Sb(Ill), and Bi(III)], Paro-toluenesulphonic acid anhydride Na[AsO(p-CH3C6H4S03h] and Na[Bi(p- It was prepared by reacting equimolar amounts CH3C6H4S03)4]' of the acid and P4010 at ::::40°C for 3 to 4 h: and extracting the anhydride with diethylether? [Ob- Materials and Methods served: S, 19.5; C, 51.42 and H, 4.32%. Required: All the reagents (As203, Sb203, Bi203, BiCI3, S, 19.6; C, 51.53 and H, 4.29%]. The molecular NaAs02, NaBi03) were dried by heating them in ion peak was observed at m/z 326. The molecular vacuo at 110°C. AsCI3 (Fluka AG) was used as ion [(p-CH3CoH4S02lz0]+ fragmented to give [(p- such. SbCI3 (E. Merck) was distilled in a current CH3C6H4)2S0J+ (mlz= 262) and a molecule of of dry oxygen-free nitrogen. BiCl3 (Thomas and S02' Formation of this fragment (M - S02)+ was Thomas) was sublimed in vacuo. Silver para- supported by the appropriate metastable ion m", toluenesulphonate was prepared by the reaction at 210 indicating the loss of S02' If the reaction of Ag20 (BDH, AnalaR) with an aqueous solution between PTS and P40lO was carried out at higher of PTS. The solution was evaporated on a water temperatures (above 60°C), the product obtained bath. The product was dried in vacuo at 100°C after extraction with diethylether was for several hours. not (p-CH3C6H4S02lz0 but para-tolyl-para- toluenesulphonate, (p-CH3C6H4S020C6H4CH3) Para-toluenesulphonic acid (PT'S) [Observed: S, 12.4; C, 64.33 and H, 5.30%. Re- p-CH3C6H4S03H.H20 (BDH) was purified by quired: S, 12.2; C, 64.12 and H, 5.34%]. removing water as toluene-water azeotrope". The acid having the minimum specific conductivity of Trl.9...para-toluenesulphonates) of arsenic, anti- 5 2.40 x 10- ohrn-) cm "! at 35°C was obtained mony, and bismuth, M(p-CH3C6H4SOJ)3 after repeating the above distillation 3 to 4 times, These compounds were prepared by stirring the each time pumping off the residual toluene. Addi- appropriate metal chloride with silver para-

982 KAPOOR et al: jrTOLUENESULPHONATO COMPLEXES OF As(I1I), Sb(III) & Bi(III)

Table 1-Analytical data of para-toluenesulphonato complexes of As(III), Sb(III) and Bi(IIl) Compound Found (Calc.), % .

M S C H

As(jrCH3C6H4S03M 1) 12.6 16.1 42.67 3.62 (12.7) (16.3) (42.86) (3.57)

Sb(jrCH3C6H.S03 h(2) 18.9 15.0 39.60 3.28 (19.2) (15.1) (39.70) (3.31)

Bi(jrCH3C6H4S03h( 3) 28.2 13.0 35.02 3.10 (28.9) (13.3) (34.91) (2.91)

SbO(jrCH3C6H4S03X4) 39.4 10.3 27.15 2.36 (39.4) (10.4) (27.21) (2.27)

BiO(jrCH3C6H4S03X5) 52.0 8.3 21.14 2.04 (52.8) (8.1) (21.22) (1.77)

Na[AsO(jrCH3C6H4S03hX6) 16.1 14.1 36.90 3.21 (16.4) (14.0) (36.85) (3.07)

Na[Bi(jrCH3C6H4S03)4 X 7) 22.4 13.8 36.51 3.17 (22.8) (14.0) (36.69) (3.06)

toluenesulphonate (mole ratio 1:3) in CH3NOz or Sodium tetrakis.para- toluenesulphonato )bismuth- CH3CN. Silver chloride formed was removed and ate (III), Nd,.B~p-CH3C6H4S03)4] the compounds recovered by distilling off the sol- Sodium bismuthate was stirred with PTS for vent in vacuo. Alternatively, the compounds could 8-10 h and bismuth (III) compound, NafBi(p- also be obtained by solvolysis of metal chlorides CH3C6H4S03)4]' was obtained after treatment in pure PTS. The excess acid was washed with with diethylether. The compound did not liberate diethylether. Bi(p-CH3C6H4S03h was also ob- 12 from acidified KI solution thereby suggesting tained by the reaction of Biz03 and (p- that bismuth was in a lower ( + 3) oxidation state. CH3C6H4SOZ)zO in CH3NOz at room tempera- ture. Pyridine complexes In a typical experiment, an excess of pyridine Biz03 + 3(p-CH3C6H4SOzlz° ....• was added to the suspension of Sb(p- 2Bi(p-CH C H S0 h CH3C6H4S03h (mole ratio 4:1) in light petroleum 3 6 4 3 ether at about - 10°C. The contents were stirred Oxd paro-toluenesulphonatesi of antimony and for a few hours, vacuum filtered, washed with fresh light petroleum ether, and finally dried in bismuth, Ma..,p-CH3C6H4S03) (M= Sb or Bi) These compounds were prepared by heating vacuo [Observed: S, 11.9; C, 46.80; H, 4.06 and the appropriate metal oxide with PTS (large ex- N, 3.42%. Required for Sb(p-CH3C6H4S03h. cess) to about 100°C for 4 to 6 h. Reaction of 2CsHsN: S, 12.1; C, 46.92; H, 3.91 and N, 3.54%]. Complexes of pyridine with other PTS Bi203 with PTS was completed at room tempera- ture in 2-3 h. Greyish-white solids were recovered salts were prepared and analysed in a similar way. after stirring the contents with diethylether.

SbO(p-CH3C6H4S03) was also prepared by the Boron tribromide complexes reaction of Sb203 with (p-CH3C6H4S02}zO. In a typical experiment, As(p-CH3C6H4S03)3 (0.84 g, 1.32 mmol) was taken in CHCl3 (10 mI) Sodium oxobis.para- toluenesulphonato )arsenate and a solution of BBr3 (0.68 g, 2.71 mmol) in

(III), Na,Asa..,p-CH3C6H4S03lz] CHCI3 (15 mI) was added dropwise. An exother- It was prepared by stirring sodium arsenite with mic reaction was observed and contents were al- PTS for 3 to 4 h and recovering the product with lowed to stir for 3 to 4 h at room temperature. diethylether. The pale-yellow solid was vacuum-filtered and

983 INDIAN J CHEM, SEe A, OcroBER 1990 dried [Observed: C, 29.34 and H, 2.64%. Re- Earlier, IR spectral studies on sulphonate li- quired for As(p-CH3C6H4S03)3.BBr 3: C, 30.05 gands have yielded useful information on ionic and H, 2.50%J. Complexes with antimony and XSO; groups 7-9, covalently bonded monodentate bismuth salts were prepared and analysed in a si- - OS02X groups'P", and bidentate bridging and milar fashion. tridentate XS03 groups+'-". Band assignments Analytical methods adopted for elemental de- have been made assuming that the C3v local termination were the same as discussed earlier'. symmetry for CS03 moiety (ionic or tridentate Infrared spectra were recorded on a Perkin-Elmer XSO; group), which would be responsible for six 1430 ratio recording spectrophotometer as nujol fundamentals, three E1vas(SO)), s, (S03) and ~r and hexachlorobutadiene mulls between KBr and (S03)] and three ~vs (S03)' v(S - C), and ~s polyethylene plates. Mass spectra were recorded (S03)] modes of IR-active vibrations, is lowered on a VG micromass mm 70170. Density measure- to C. (or Cl) on monodentate or bidentate type of ments were made on a PAAR DMA 602 dens i- coordination. With the lowering of symmetry the tymeter. Conductances of solutions were mea- three E modes are split to give six bands, and a sured directly using a Toshniwal conductivity total of nine IR-active bands be expected. bridge (type CL 0l/02A). Inspection of Table 2 reveals that the IR spect- Analytical results of the compounds prepared ra of these compounds are quite identical, indicat- above are summarized in Table 1. ing strong structural similarity between them. The doubly degenerate SO) asymmetric stretching

Results and Discussion (v4) and S03 asymmetric bending (vs) modes Arsenic(III), antimony(III) and bismuth(III) ox- show splitting which suggest that the local symme- ides reacted with methanesulphonic acid anhy- try of the CS03 moiety is reduced below C)v- The dride, (CHJhS20S to yield M(S03CH3h type of para-toluenesulphonate group may be acting as a compounds', but reaction of Sb203 and Bi203 unidentate ligand which would be consistent with with para-toluenesulphonic acid anhydride yielded metal ions acquiring coordination number 3 in

SbO[p-CH)C6H4S03l and Bi(p-CH3C6H4S03)) compounds (1) to (3). In this mode, one oxygen with As20) showing no reaction. This change in atom is different from the other two and it is in- the nature of the products may be attributed to volved in bonding to metal ions. In oxo com- the increased basicity of the metal on moving plexes, there was no evidence of the existence of from arsenic to bismuth. The difference in the discrete M = ° species owing to the absence of a reactivities of methanesulphonic acid and para- sharp intense band in the region 900-1000 em - 1. toluenesulphonic acid anhydrides towards these Probably, oxygen acts as a bridging atom to given oxides suggests lower acidity of the latter com- polymeric structures. pound. Pyridine formed 1:2 addition compounds with Tris(para-toluenesulphonates) of arsenic, anti- M(p-CH)C6H4S03)3 (M=As, Sb and Bi) and 1:1 mony and bismuth could be prepared by the met- complexes with MO(p-CH3C6H4S03) (M = Sb and athetical reaction: Bi) thereby suggesting that the metal atom in CHJ"'O, these compounds retained lewis acid character. MCl1 + :ip-CH)C6H4SO)Ag Coordination of pyridine in these complexes did M(p-CH3C6H4S03h + 3AgCI not result in any significant change in the S - 0 stretching modes. This observation is consistent compounds (1) to (3) (see Table 1 for numbering) with the fact that PTS group acts as a unidentate were off-white in colour. They were sensitive to ligand in these compounds and M(p- moisture and decomposed when exposed to moist CH3C6H4S03h. 2NCsHs and. MO(p- air. They were soluble in polar organic solvents CH3C6H.:SOJ NCsHs may be assigned coordina- such as CH)N02' C6HSN02' CHiCN and DMSO. tion numbers 5 and 4. respectively. Bands due to Their millimolar solutions in CH3CN and C-C and C- N stretching modes, usually observed I, C6HsNOz were non-conducting thus suggesting between 1450 and lA15 cm- have been ob- that the (p-CH3C6H4SO; )group is covalently served with a slight upwards shift!". M(p- bonded to metal atom. Behaviour of these com- CH3C6H4S03h (M = As, Sb, and Bi) compounds pounds in terms of their ionization in para- also functioned as lewis bases by forming 1:1 toluenesulphonic acid either as acidic or basic so- complexes with BBr 3' It was not possible to char- lutes could not be ascertained owing to the highly acterize these adducts by IR because of their ex- viscous nature of the acid and their limited solu- tremely reactive nature. bility. Reactions of M(p-CH3C6H4S03)3 with

984 KAPOOR et al: p-TOLUENESULPHONATO COMPLEXES OF As(III), Sb(lII) & Bi(III)

Table 2 - Pertinent infrared spectral bands (em - •)of some para-toluenesulpbonates

Assignment Compounds (C)v) 1 2 3 4 5 6 7 8t 1220s, v4(E){SO) as. str.] 1270m, 1270m 1260m, 1280m, 1240m, 1240m, 1275m, ,br 1045m,br 1040s,br 1040s,br 1040s,br 1190m,br 121Om,br 1190s, 1180s,

v.(AtXSO) sym. str.] 1030s,br ,br 1030s,br 1025s,br 1020s,br 1120m,br 1130m,br 1125s

vz(AtXSC str.] 680m 670m 670m 660m 670m 705m 6905 680s 670s

VS(E)[S03 sym. defn.] 550s, 5405, 550m, 540m, 540m, 595m, 605m, 560m 500sb 510w 520w 500sb 500sb 560m 550m

v3(AtXS03 sym. defn.] 460m 440m 430m 450m 440m 470w 490w 495m

v6(E)[SR defn. & p-CH3C6H4 1380m, 1370m, 1370m, 1380m, 1370m, 138Ow, 1370m, 1380m, internal vib.] 11205, 11105; 11205, 11205, 1110s, 1170sb, 1l05m, 8105, 8105, 805m, 810m, 800s, 815m, 450w 470w 700w, 700w, 704w, 700w, 700sh, 120m, 380w 400m 380m 410w 400w 360w

• Numbering according to Table 1 tNa+(p-CH3C6H4SOi]

(CH3)4N+Br- yielded yellow compounds corre- 5 Feld R,J chem Soc; (1964) 3963. sponding to composition (CH3)4N+ (MBri) 6 Bredereck H, Wagner A, Beck H & Klein R J, Chern Ber, (1960) 2736. (M = As, Sb and Bi) in which p-CH C H S03" 3 6 4 7 Miles M G, Doyle G, Cooney R P & Tobias R S, Spectro- was replaced by more electronegative Be. The chirn Acta, Part A, 25A (1969) 1515. highly polarizable nature of para-toluenesulphon- 8 Burger H, Burezyk K & Blaschette A, Mh Chern, 101 ate ion can be used in preparing other derivatives (1970) 102. of these elements. IR spectra of these compounds 9 Gillespie R J & Robinson E A, Can J Chern, 40 (1962) did not show any band which might be assigned 644. 10 Wechsberg M, Bulliner P A, Sladky F 0, Mews R & to sulphur-oxygen stretching modes. Bartlett N, Inorg Chern, 11 (1912) 3063. 11 DaizieIJR & AbukeF,InorgChern, 12(l973) 2707. References 12 Sharma S K, Mahajan R K, Kapila B & Kapila V P, Po- 1 KapoorR, Wadbawan P & Kapoor P, Can J Chern, 65 lyhedron, 2 (1983) 973. (1987) 1195. 13 Yeats P A, Sams J R & Abuke F, Inorg Chern, 11 (1972) 2 Mutterties E L & Coffman D D, ] Am chem Soc; 40 2634. (1958) 5914. 14 Arduini A L, Garnett M, Thompson R C & Wong C T C, 3 Singh S, Amita & Verma R D, Indian J Chern, 22A Can] Chern, 53 (1975) 3812. (1983)814. 15 Haynes J S, Sams J R & Tbompson R C, Can ] Chern, 4 Paul R C, Singh S, Kumar R C, Sharma R D & Verma R 59 (1981) 669. D, Indian] Chern, 17A (1979) 273. 16 Greenwood N N & Wade K, ] chem Soc, (1960) 1l30.