Adducts of trigonal-prismatic and octahedral metal clusters containing interstitial atoms (nitrogen or carbon) with [Au(PPh3)]+

Abstract

Spectroscopic evidence indicates that the anion [Rh₆N(CO)₁₅]^– reacts with [Au(PPh₃)Cl] to afford [Rh₆N(CO)₁₅{Au(PPh₃)}], but there is no evidence that a similar reaction with either CF₃CO₂H or HBF₄·Et₂O leads to [Rh₆(H)N(CO)₁₅]. Addition of [Au(PPh₃)Cl] to [Rh₆C(CO)₁₃]^2– at –80 °C gives [Rh₆C(CO)₁₃{Au(PPh₃)}]^–, in which there is complete migration of the Au(PPh₃) group and all the carbonyls around the Rh₆ octahedron even at –80 °C. At higher temperatures, [Rh₆C(CO)₁₃{Au(PPh₃)}]^– loses CO and forms [Rh₆C(CO)₁₂{Au(PPh₃)}]^–, which has been characterised by a variety of multinuclear NMR measurements. Spectroscopic evidence is presented to suggest that a related 84-electron octahedral cluster [Rh₆N(CO)₁₂]^– is formed, rather than the 86-electron cluster [Rh₆N(CO)₁₃]^–, on heating [Rh₆N(CO)₁₅]^–.