SYNTHETIC METHODOLOGIES FOR TRIPODAL PHOSPHINES - THE PREPARATION OF MESI(CH(2)PPH(2))(3) AND N-BUSN(CH(2)PPH(2))(3) AND A COMPARISON OF THEIR RHODIUM(I) AND RUTHENIUM(II) COORDINATION CHEMISTRY - THE X-RAY CRYSTAL STRUCTURES OF [RH(NBD)(N-BUSN(CH(2)

摘要

The preparation of the new tripodal ligands MeSi(CH(2)PPh(2))(3) (Si-triphos) and n-BuSn(CH(2)PPh(2))(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 the 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(CH(2)PPh(2))(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(CH(2)PPh(2))(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 sufficient to stabilize the mononuclear, five-coordinate dichloro complexes. [References: 78]