Rhodium and iridium complexes of the general formula (PP2)MX bearing the new triphosphine ligand iPr2P(CH2)3P(Ph)(CH2) 3PiPr2 (PP2) have been synthesized. Reactivity of the PP2MX complexes toward HSi(SEt)3 was studied. Whereas (PP2)RhCl and (PP2)IrCl do not react with HSi(SEt)3, (PP2)RhH gives rise to the Rh(III) adduct [(PP2)Rh(H)2Si(SEt)3], and (PP2)RhMe (3) activates both the Si-H and the Si-S bonds of HSi(SEt)3, affording the Rh(I) complexes (PP2)RhSi(SEt)3 (5) and (PP2)RhSEt (6). Only a few stable Rh(I) silyl complexes are known, and Si-S bond activation by transition-metal complexes has been rarely observed. The X-ray crystal structure of 5 exhibits a considerable distortion from square-planar geometry, the average angle between the trans-disposed ligands being 152.5°. In contrast to 3, (PP2)IrMe (8) forms a stable Ir(III) adduct with HSi(SEt)3, fac-[(PP2)Ir-(Me)(H)(Si(SEt)3)] (9). No Si-S activation was observed with 8. Thus, the reactivity of (PP2)-MX complexes toward HSi(SEt)3 strongly depends on the nature of M and X.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry