Indian Journal of Chemistry Vol. 43A, August 2004, pp. 1667-1671 Triphenylantimony(V)dichloride molecular adducts with some thiosemicarbazones Ki shori Dalvi, Mamta Pal & Shivram S Garje* Department of Chemistry, University of Mumbai , Vidyanagari, Santac ru z (East), Mumbai 400098 , India Ema il : ssgarje@yahoo.com Received 4 April 2003; revis ed 4 Jlllle 2004 The reaction of triphenylantimony(V)dichloride with one mole equivalent of thi osemicarbazone li gands yields th e molecu lar adducts of th e type Ph J SbCl 1 . N" S (N" S = thi osem ica rbazo nes). These compo und s havc been characterized by elemc ntal analysis, IR and IH and "c NMR spectral data a nd co ndu ctome tri c measurements. The stru ctures of th ese molecular add ucts ha ve bee n proposed on the ba s is of spcctroscopic data. IPC Code: Int. CI. 7 C07F 9/92 The Schiff ba se complexes of main group elements containing li ga nds such as semicarbazones and thiosemicarbazones have remain ed a topic of considerable current re sea rch interest ' - '9 . This is mainly because of biological applications of not o nly ligands but also compounds derived from them. Semi- and thiosemicarba zo nes can act as neutral or charged li gands. They can show tautomerism and can exist in ketolthione or enol/thiol form. Usually coordination through O/S and N(3) is observed. However, in few cases an unusual coordination through N(2) has been reported 2o . 21 . O/S O/SH II I RR'C=N(3)-N(2)H -C-N( I )Hl = RR'C=N(3)-N(2)=C-N( I)Hl thi one thi ol A large number of lin co mpl exes with these ligands ha ve been studied extensively5.7.'3.'6.'7.'9.21. However, very few such compounds of antimony have been reported 22 - 24 . Triorganoantimonydihalides are known to show Lewis acidity. Thus, their neutral as well as charged adducts were studied 25 . 28 . The present note reports the synthesis and characterization of triphenylantimony(V) dichloride molecular adducts with some potentially bidentate thiosemicarbazone ligands. Experimental All reactions were carried out in oxygen free nitrogen atmosphere. The analytical grade solvents were used and they were dried prior to use. Triphenylantimony(V) dichloride was prepared by chlorination of triphenylantimony (Lancaster) in CCl 4 . Thiosemicarbazone ligands were prepared by the reported methods I. The elemental analysis was carried out in microanalytical laboratory of this department. IR spectra were recorded as Nujol mulls between Csi plates on a Bomem MB-102 spectrophotometer in the 4000-200 cm- I range. 1 H and IJC spectra were recorded in 5 mm NMR tube in DMSO-d 6 on a Varian XL-300 spectrometer. The chemical shifts are relative to internal standard TMS. The conductometric measurements were carried o ut in DMF on a Toshniwal conductometer. The melting points taken are uncorrected. Preparation of Ph 3 SbCI 2 (actscz) To a weighed quantity of acetonethiosemi- carbazone (0.236 g, 1.800 mmol) in tetrahydrofuran , 0.764 g (1.802 mmol) of triphe ny lantimony(V) dichloride was added with constant stirring and the stirring was continued for 20 h. The colour of so luti on changed slowly to yellow. Then the solvent was evaporated in vacuum and the resulting semisolid was washed repeatedly with cyclohexane. The product was dried under vacuo and weighed (yield 0.550 g, 55%). Preparation of Ph 3 SbClifurtscz) To a weighed quantity of 2-furfuralaldehyde thiosemicarbazone (0.321 g, 1.896 mmol) dissolved in tetrahydrofuran, 0.805 g (1.899 mmol) of tripheny l- antimony(V) dichloride was added and the solution was stirred for 12 h. The colour of solution turned yellow immed iate ly . The solvent was evaporated in vacuum and the resulting solid was repeatedly washed with cyclohexane. The product obtained was dried in vacuum (yield 0.725 g, 64.39 %) . Similarly, all other complexes were prepared. Results and discussion Treatment of thiosemicarbazone ligands with Ph]SbCh in 1: I stoichiometry in dry THF gave molecular adducts of the type Ph ]S bCh.N"S [N"S =