Synthetic methodologies for tripodal phosphines. The preparation of MeSi(CH2PPh2)3 and n-BuSn(CH2PPh2)3 and a comparison of their rhodium(I) andruthenium(II) coordination chemistry. The X-ray crystal structures of [ Rh(NBD){n-BuSn(CH2PPh2)3}](OTf) and [Rh(NBD){MeSi(CH2PPh2)3}](OTf)

Article abstract of DOI:10.1016/0020-1693(95)90063-C

The preparation of the new tripodal ligands MeSi(CH2PPh2)3 (Si-triphos) and n-BuSn(CH2PPH2)3 (Sn-triphos) and their complexes of rhodium(I) of the type [Rh(NBD)(tripod)](OTf) (NBD=norbornadiene, OTf=triflate) and of ruthenium(II) of type [Ru(O2CCF3)2(tripod)], is reported. The coordination chemistry of the new tripodal phosphines, and in particular that of Sn-triphos, differs significantly from that of MeC(CH2PPh2)3 (triphos). A comparison of the X-ray structure of [Rh(NBD)(triphos)](OTf) with those of the new complexes [Rh(NBD)(Sn-triphos)](OTf) and [Rh(NBD)(Si-triphos)](OTf) shows that the steric requirements of the ligands RE(CH2PPh2)3 (E=C, Si and Sn), increase from the carbon to the tin compound. The coordination chemistry of ruthenium(II) indicates that, relative to triphos,Sn-triphos displays an enhanced steric bulk which, however, is not suff icient to stabilize the mononuclear, five-coordinate dichloro complexes.