AbstractIn order to study the properties of sulfur coordinated transition metal centers. [MoCl2dttd] (dttd2 = 2,3,8,9-dibenzo-1,4.7,10-tetrathiadecane(2-)) was reacted with NO in the presence of Zn. [Mo(NO)2dttd] was obtained whose X-ray structure analysis shows that Mo is coordinated pseudo-octahedrally by two trans thiolato S, two cis thioether S as well as two cis N atoms of nearly linear MoNO groups. With respect to its low v(NO) frequencies (1760/1665 cm -1) and quite normal bond lengths as well as angles [Mo(NO)2dttd] shows unexpectedly facile and rapid reactions with nucleophiles; with two equivalents of PR3 (PMe3, PEt3, PMePh2, PEtPh2, PPh3) it yields the corresponding phosphiniminato complexes [Mo(NO)(NPR3)dttd] and free phosphinoxides OPR3, respectively. Reaction mechanisms as well as the bonding situation in the [Mo(NPR3)] entity are discussed; on the basis of 95Mo and 14N NMR it is concluded that the conversion of NO into NPR3 ligands includes a reduction of N(+2) to N(-3) as well as an oxidation of (formal) Mo(+2) to Mo(+3). With H2O the [Mo(NO)(NPR3)dttd] complexes hydrolyze with loss of the NPR3 ligands and formation of binuclear [Mo(NO)dttd]2. The ease of hydrolysis depends on the substituents R: In THF [Mo(NO)(NPMe3)dttd] hydrolyzes at 20 °C within a few minutes, [Mo(NO)(NPPh3)dttd], however, needs the addition of cone. HCl.
Special Issue on Recent Developments of the Study on Catalytic Reaction Mechanisms. Understanding of the Catalytic Reactions of Transition Metal Complexes by Using Molecular Orbital Method.
