Heterometallic octahedral boride cluster chemistry: reactions of [Rh2Ru4(CO)(16)B](-) with PPh3 and P(OMe)(3), and the crystal structures of [Rh2Ru4(CO)(16)B(AuPPh3)] and [Rh2Ru4(C0)(14)(PPh3)(2)B(AuPPh3)]

摘要

The reaction between [(PPh3)(2)N][Rh2Ru4(CO)(16)B] and five-fold excess of PPh3, followed by addition of Ph3PAuCl leads to the formation of [Rh2Ru4(CO)(15)(PPh3)B(AuPPh3)] and [Rh2Ru4(CO)(14)(PPh3)(2) B(AuPPh3)]. Phosphorus-31 NMR spectroscopic data were in accord with substitution at the Rh centres; and X-ray diffraction study of [Rh2Ru4(CO)(14)(PPh3)(2)B(AuPPh3)] showed that the Rh atoms occupied cis-sites in the octahedral Rh2Ru4-cage. The reaction between [(PPh3)(2)N][Rh2Ru4(CO)(16)B] and a five-fold excess of PPh3, followed by addition of CF3CO2H yielded [HRh2Ru4(CO)(15)(PPh3B], [HRh2Ru4(CO)(14)(PPh3)(2)B] and [HRh2Ru4(CO)(13)(PPh3)(3)B], their formations being dependent on reaction conditions. Treatment of [(PPh3)(2)N] [Rh2Ru4(CO)(16)B] and P(OMe)(3) (I : 1) followed by Ph3PAuCl leads to the formation of [Rh2Ru4(CO)(16) B(AuPPh3)] (for which an X-ray structural determination has been carried out), [Rh2Ru4(CO)(15){P(OMe)(3)} B(AuPPh3)] and [Rh2Ru4(CO)(14){P(OMe)(3)}(2)B(AuPPh3)]. By altering the cluster:phosphite ratio to 1:3, the major product was [Rh2Ru4(CO)(13) {P(OMe)(3)}(3)B(AuPPh)(3))]. The addition of CF2CO2H in place of Ph3PAuCl to the crude products of the reaction between [(PPh3)(2)N] [Rh2Ru4(CO)(16)B] and P(OMe)(3) promoted cleavage of the P-O bond and results in the formation of [Rh2Ru4(CO)(14){P(OME)(3)}{mu-P(Me)(2)}B] and [Rh2Ru4(CO)(13) {P(OMe)(3)}(2){mu-P(OMe)(2)}B]. Products have been characterized by IR and multi-nuclear NMR spectroscopies and mass spectrometry, and evidence for cis-trans isomerization of the Rh2Ru4-framework is presented. (C) 1998 Elsevier Science Ltd. All rights reserved. [References: 14]