Heterometallic adducts of [Rh6(CO)15C]2–, including the novel double- and triple-decker sandwich compounds [Agn{Rh6(CO)15C}2](4–n)–(n= 1 and 3) and [Agn{Rh6(CO)15C}3](6–n)–(n= 2 and 4) and the X-ray structural characterisation of [PPh4]3[Ag{Rh6(CO)15C}2

Abstract

Multinuclear n.m.r. measurements have been used to establish the formation of the following new adducts of [Rh6(CO)15C]2– by capping the trigonal face of the Rh6 trigonal prism: [{M(PEt3)}{Rh6(CO)15C}]–(M = Ag or Au), [Agn{Rh6(CO)15C}2](4–n)–(n= 1 or 3), [Agn{Rh6(CO)15C}3](6–n)–(n= 2 or 4), [Agn{Rh6(CO)15C}n]n–(n > 3), and [Ag2{Rh6(CO)15C}]. There is no evidence for dissociation of any of these species on the n.m.r. time-scale, whereas n.m.r. spectra suggest that dissociation of [Cu(NCMe)]+ occurs in [{Cu(NCMe)}n{Rh6(CO)15C}](2–n)–(n= 1 or possibly 2) both at room and low temperature. X-ray crystallographic analysis of [Ag{Rh6(CO)15C}2]3– shows that a silver atom is sandwiched between trigonal faces of two staggered Rh6 trigonal-prismatic units and the nature of the silver–rhodium interaction is discussed.