SYNTHESES, STRUCTURES, AND SPECTROSCOPIC PROPERTIES OF NOVEL SULFURDIIMINE COMPLEXES - SPECTROSCOPIC PROPERTIES OF THE DI-T-BUTYLSULFURDIIMINE (DBSD) COMPLEXES M(CO)(3)BR(DBSD-N,N') (M=MN, RE) AND X-RAY STRUCTURES OF THE METAL-METAL BONDED COMPOUNDS (CO)(8)MN-2(DBSD-N,N') AND (CO)(6)MN-2(MU-DBSD-N,N'- N, S, N')

The complexes M(CO)(3)Br(DBSD-N,N') (M = Mn or Re; DBSD = di-t-butylsu lfurdiimine = (t)Bu-N=S=N-(t)Bu) have been prepared by reaction of M(C O)(5)Br with DBSD. The complexes have been characterized spectroscopic ally (H-1-NMR, IR, UV/Vis and resonance Raman) and used as starting ma terials for the preparation of the metal-metal bonded complexes (CO)(8 )MM'(DBSD-N,N')(M,M' = Mn, Re). The structure of (CO)(8)Mn-2(DBSD-N,N' ) has been determined by X-ray crystallography. Both Mn atoms have sli ghtly distorted octahedral geometry, and the Mn-Mn distance (2.967 Ang strom) is longer than that in Mn-2(CO)(10) (2.9038 Angstrom. The DBSD is bonded to Mn as a chelate in its trans, trans-conformation, and the N-S bond lengths and NSN bond angle are nearly the same as in W(CO)(4 )(DBSD-N,N'). The complexes (CO)(8)MM'(DBSD-N,N') are transformed ther mally and photochemically into (CO)(6)MM'(mu-DBSD-N,N':N,S,N'); during this reaction the coordination of the DBSD ligand changes from chelat e to bridging. This has been established by an X-ray structural study of (CO)(6)Mn-2(mu-DBSD-N,N':N,S,N'). Both Mn atoms possess a distorted octahedral geometry and the Mn-Mn distance (2.638 Angstrom) is very s hort. The N-S bond distances are increased from similar to 1.60 Angstr om in the unbridged complex to similar to 1.70 Angstrom in this bridge d species, which contains the longest N-S bond observed so far for a s ulfurdiimine ligand. The mechanism of the photochemical formation of t his complex is discussed.