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

Two kinds of dinuclear cobalt(III) complexes sym-(meso- and rac-)[{Co(en)2)2(mu-ttcy)]X3 and sym-[meso- and rac-)[{Co(en)2}2(mu-dtcy)]X3 (en=ethane-1,2-diamine, H-3ttcy = 1,3,5-triazine-2,4,6-trithione, H-3dtcy = 4-oxo-1,3,5-triazine-2,6-dithione) have been prepared photochemically from [Co(en)3]Cl3, H-3ttcy 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(mu-ttcy)] [ClO4]3.2H2O and sym-meso-[{Co(en)2}2-(mu-dtcy)]I3.4H2O 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 P2(1)/a, a = 14.392(4), b = 14.807(4), c = 14.816(4) angstrom, beta = 92.83(3)-degrees and Z = 4; monoclinic, space group P2/c, a = 18.088(3), b = 8.146(6), c = 21.757(3) angstrom, beta = 93.25(l)-degrees 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(l), 3.21 (i ) angstrom] were formed between the free sulfur atom of the ttcy and the two amine protons of the en in the ttcy complex.