Molecular structures and some properties of tris(2-aminoethyl) amine cobalt(III) complexes with thiocarboxylato- O, S such as 3-mercaptopropionato, 2-mercaptoacetato and their derivatives

Abstract

Cobalt(III) complexes with a thiolate or thioether ligand, t-[Co(mp)(tren)] + ( 2), t-[Co(mtp)(tren)] 2+ ( 1Me) and t-[Co(mta)(tren)] 2+ ( 2Me), (mp = 3-mercaptopropionate, ma = 3-(methylthio)propionate and mta = 2-(methylthio)acetate) have been prepared in aqueous solutions. The crystal structures of 1, 2, 1Me and 2Me were determined by X-ray diffraction methods. The crystal data are as follows, t-[Co(mp)(tren)]ClO 4 ( 1CIO 4): monoclinic, P2 1/ n, a = 10.877(8), b = 11.570(4), c = 12.173(7) A ̊ , β = 92.20(5)°, V = 1531(1) A ̊ 3, Z = 4 and R = 0.060; t-[ Co(ma)(tren)] Cl·3H 2O (2Cl·3H 2O): monoclinic, P2 1/ n, a = 7.7688(8), b = 27.128(2), c = 7.858(1) A ̊ , β = 100.63(1)°, V = 1627.7(3) A ̊ 3, Z = 4 and R = 0.066 ; (+) 465 CD- t-[ Co( mtp)( tren)]( ClO 4) 2 ((+) 465 CD- 1Me(ClO 4) 2): orthorhombic, P2 12 12 1, a = 10.6610(7), b = 11.746(1), c = 15.555(1) Å, V = 1947.9(3) A ̊ 3, Z = 4 and R = 0.068 ; (+) 465 CD- t-[Co(mta)(tren)](ClO 4) 2 ((+) 465 CD- 2Me(ClO 4) 2): orthorhombic, P2 12 12 1, a = 10.564(1), b = 11.375(1), c = 15.434(2) A ̊ , V = 1854.7(4) A ̊ 3, Z = 4 and R = 0.047 . All central Co(III) atoms have approximately octahedral geometry, coordinated by four N, one O, and one S atoms. All of the complexes are only isomer, of which the sulfur atom in the didentate-O,S ligands are located at the trans position to the tertiary amine nitrogen atom of tren. 1 and 1Me contain six-membered chelate ring, and 2 and 2Me do five-membered chelate ring in the didentate ligand. The chirality of the asymmetric sulfur donor atom in (+) 465 CD- 1Me is the S configuration and that in (+) 465 CD- 2Me is the R one. The 1H NMR, 13C NMR and electronic absorption spectral behaviors and electrochemical properties of the present complexes are discussed in relation to their stereochemistries.