A series of palladium(II) complexes with nitro- and formylbenzothiacrown-ether derivatives was synthesized. The spatial structure of the complexes was studied by NMR, X-ray diffraction analysis, and quantum chemical calculations (density functional theory). The cavity size and the ligand denticity were found to be crucial factors determining the geometric configuration of the thiacrown-ether complexes. Palladium(II) complexes with benzodithia-12(18)-crown-4(6) ethers were demonstrated to have a cis-configured S(2)PdY(2) fragment (Y = Cl, OAc). In the case of Pd(II) and benzodithia-21-crown-7 ethers, only complexes with a trans configuration of the S(2)PdY(2) fragment form. In the case of Pd(II) and nitrobenzomonothia-15-crown-5 ether, only 2(ligand):1(Pd) complex with trans configuration of the core fragment forms.

The condensation reaction of 1,2 bis(2 haloethoxy) 4 nitrobenzenes with acyclic α,ω (oxa)alkanedithiols in the presence of alkali metal carbonates produced a series of nitrobenzodithiacrown ethers with macrocycles of different size. The structures of three ethers were established by X ray diffraction. A new method was developed for the synthesis of nitrobenzomonothia 15 crown 5 ether. Nitro derivatives of benzodithiacrown ethers were tested as reagents for extraction of palladium(II), platinum(IV), and rhodium(III) from hydro chloric acid solutions. Extraction of Pd II salts was found to be highly selective compared to that of Pt IV and Rh III salts. Benzodithia 15 crown 5 ether is the most efficient extractant for palladium(II). Reduction of nitrobenzothiacrown ethers with hydrazine hydrate in the pres ence of a platinum catalyst afforded their amino derivatives.Thiacrown ethers are among the most promis ing macrocyclic sulfides. 1,2 Sulfur containing macro heterocycles have attracted interest because these com pounds can form stable complexes with transition and heavy metal ions. 3,4 These compounds can be used as selective extractants, materials for ion selective electrodes, reagents for modifications of chromato graphic sorbents, etc. The development of procedures for the synthesis of important functionalized derivatives of thiacrown ethers is of great importance for the exten sion of the possibilities of the practical use of these com pounds.In the present study, we developed convenient proce dures for the synthesis of nitro and amino derivatives of benzothiacrown ethers with macrocycles of different size and different combinations of O and S atoms. The con densation reactions of 1,2 bis(2 haloethoxy) 4 nitroben zenes 1a,b with terminal (oxa)alkanedithiols 2a-d in the presence of alkali metal carbonates (M 2 CO 3 ) in aqueous ethanol produced nitrobenzodithiacrown ethers 3a-d in 48-89% yields (Scheme 1). To suppress side reactions, Scheme 1