1,4,7‐Trithiacyclononane as a Tridentate Ligand for Complexation of Heavy‐Metal Ions: Synthesis and Complexation Studies of Mesocyclic and Macrocyclic Polythioethers IV

Bis octahedral complexes of 1,4,7‐trithiacyclononane (9‐ane‐S 3 ) with Group 12 metal ions Zn(II), Cd(II), and Hg(II), as well as Pb(II), have been prepared. Two equivalents of 9‐ane‐S 3 react with Zn(BF 4 ) 2 ·6H 2 O, Cd(ClO 4 ) 2 ·6H 2 O, Hg(ClO 4 ) 2 ·3H 2 O, and Pb(ClO 4 ) 2 . 3H 2 O, respectively, to give stable crystalline complexes of the formula [M(9‐ane‐S 3 ) 2 ] 2 + 2X − . Single‐crystal X‐ray structures of the zinc and mercury complexes have been determined. The zinc complex crystallizes in the orthorhombic space group Pbca with four molecules per unit cell (a = 9.219(3) Å, b = 15.400(5) Å, and c = 19.965(10)Å; R = 7.6%) whereas the mercury complex crystallizes in the monoclinic space group P2 1 /c with two molecules per unit cell (a = 10.400(3) Å, b = 15.190(4) Å, c = 9.533(3) Å, and p = 99.09(3)°; R = 5.2%). In each structure, the metal atom is located on a crystallographic center of inversion and is octahedrally surrounded by six sulfur atoms provided by the two facially coordinating tridentate ligands. Reaction of 9‐ane‐S 3 with RuCl 3 ·xH 2 O displaces chloride ions with concomitant reduction of Ru(III) to Ru(II), giving the octahedral thioether complex, [Ru(9‐ane‐S 3 ) 2 ]Cl 2 ·4H 2 O. Reaction of the ligand with RhCl 3 , on the other hand, gives (9‐ane‐S 3 )RhCl 3 . A single‐crystal X‐ray structure determination has been done on the Ru(II) complex (triclinic space group P 1 ̅; a = 7.652(1) Å, b = 8.946(1) Å, c = 9.042(1) Å, α = 93.43(1)°, β = 103.43(1)°, and γ = 107.79(1)°; R = 2.8%) and this complex is also octahedral with the metal center at an inversion center.