名称:
Syntheses, structures, and spectroscopic properties of novel sulfurdiimine complexes; spectroscopic properties of the di-t-butylsulfurdiimine (DBSD) complexes M(CO)3Br(DBSD-N,N′) (M Mn, Re) and X-ray structures of the metal-metal bonded compounds (CO)8Mn2(DBSD-N,N′) and (CO)6Mn2(μ-DBSD-N,N′: N, S, N′)
摘要:
The complexes M(CO)(3)Br(DBSD-N,N') (M = Mn or Re; DBSD = di-t-butylsulfurdiimine = (t)Bu-N=S=N-(t)Bu) have been prepared by reaction of M(CO)(5)Br with DBSD. The complexes have been characterized spectroscopically (H-1-NMR, IR, UV/Vis and resonance Raman) and used as starting materials 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 slightly distorted octahedral geometry, and the Mn-Mn distance (2.967 Angstrom) 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 thermally and photochemically into (CO)(6)MM'(mu-DBSD-N,N':N,S,N'); during this reaction the coordination of the DBSD ligand changes from chelate 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 short. The N-S bond distances are increased from similar to 1.60 Angstrom in the unbridged complex to similar to 1.70 Angstrom in this bridged species, which contains the longest N-S bond observed so far for a sulfurdiimine ligand. The mechanism of the photochemical formation of this complex is discussed.