Photochemical synthesis and crystal structures of tetrakis(ethane-1,2-diamine) dicobalt(III) complexes bridged by 1,3,5-triazine-2,4,6-trithionate and 4-oxo-1,3,5-triazine-2,6-dithionate

Abstract

Two kinds of dinuclear cobalt(III) complexes sym-(meso- and rac-)[{Co(en)₂}₂(µ-ttcy)]X₃ and sym-[meso- and rac-)[{Co(en)₂}₂(µ-dtcy)]X₃(en = ethane-1, 2-diamine, H₃ttcy = 1,3,5-triazine-2,4,6-trithione, H₃dtcy = 4-oxo-1,3,5-triazine-2,6-dithione) have been prepared photochemically from [Co(en)₃]Cl₃, H₃ttcy and NaOH and characterized by elemental analysis, IR, UV/VIS and NMR spectroscopy. The dtcy complexes are formed via a novel desulfurization of the ttcy ligand. Two crystal structures, sym-meso-[{Co(en)₂}₂(µ-ttcy)][ClO₄]₃·2H₂O and sym-meso-[{Co(en)₂}₂-(µ-dtcy)]l₃·4H₂O were determined from 1859 and 4146 reflections to R= 0.056 (R′= 0.060) and R= 0.069 (R′= 0.073), respectively: monoclinic, space group P2₁/a, a= 14.392(4), b= 14.807(4), c= 14.816(4)Å, β= 92.83(3)° and Z= 4; monoclinic, space group P2/c, a= 18.088(3), b= 8.146(6), c= 21.757(3)Å, β= 93.25(1)° and Z= 4. The bridging ttcy and dtcy ligands co-ordinate symmetrically through the two N and S donor sets and both complexes are in the meso form. Marked symmetric intramolecular hydrogen bonds N–H ⋯ S[N ⋯ S 3.19(1), 3.21(1)Å] were formed between the free sulfur atom of the ttcy and the two amine protons of the en in the ttcy complex.