PHOTOCHEMISTRY OF COBALT(III) COMPLEXES .2. COBALT(III) COMPLEX WITH A CO-C-S 3-MEMBERED RING PREPARED BY PHOTODECARBOXYLATION OF 2,2'-THIODIACETATO COMPLEX - CRYSTAL-STRUCTURE OF 37)(CD)-FAC-TRANS(NH,O)-[CO(CH2SCH2COO)(DIEN)]CLO4

The diethylenetriamine (dien) cobalt(III) complex with a Co-C-S three- membered ring, fac-trans-(NH, O)-[Co(CH2SCH2COO)(dien)](+) (1), has be en prepared in an aqueous solution by the photodecarboxylation of u-fa c- (2) or s-fac-[Co(2,2'-thiodiacetato)(dien)](+) (3). Perchlorate sal t of 1 was subject to spontaneous resolution, and the crystal structur e and absolute configuration for the (-)(537)(CD) isomer were deter mi ned by X-ray diffraction. The crystal is monoclinic, space group P2(1) , a=6.962(1), b=13.411(1), c=7.663(1) Angstrom, beta=101.921(8)degrees , V=700.1(2) Angstrom(3), Z=2, and R=0.032. The formation of the Co-C- S three-membered ring introduces a significant distortion into the oct ahedral coordination around the Co atom (angle C-Co-S=49.4(1)degrees), although the bond lengths in the Co-C-S ring are within the range nor mally observed for other complexes. For the (-)(537)(CD) isomer the ch iral configuration is regulated Delta Lambda Delta and and R for the s ulfur atom. The racemization rate of 1 is very fast in water and DMSO. The position of the first d-d band of 1 is red-shifted by 1600-1100 c m(-1) relative to those of 2 and. The photolysis of mer-[Co(3,3'-thiod ipropionato)(dien)](+) did not give a similar product to 1.