Fluxional behaviour of the carbonyls [M3(CO)12](M = Fe, Ru or Os)

Analysis of Single-Crystal Diffuse X-Ray Scattering via Automatic Refinement of a Monte Carlo Model

“…For the present, it may be said that the results obtained here clearly demonstrate that the motion of the iron triangle within its icosahedron of carbonyl ligands can be described in terms of a libration of the iron triangle about the pseudo-twofold axis passing through the unique Fe atom, Fe(1) (Johnson & Bott, 1990;Braga et al, 1990;Johnson et al, 1992Johnson et al, , 1993. The chemical implications of the results obtained for the compound Fe 3 (CO) 12 are still the subject of further study and a more detailed discussion of these will be published elsewhere.…”

On the nature of [Fe 3 (CO) 12 ] in the solid-state: The Ligand Polyhedral Model approach to the observed disorder

“…In a series of subsequent papers [2,3,4,5] we demonstrated that the model works remarkably well for a comprehensive range of neutral and anionic carbonyl clusters permitting for the first time a clear understanding of the apparently anomalous structures of, for example [Fe 3 (CO) 12 ], [Co 4 (CO) 12 ] and [Rh 6 (CO) 16 ]. The model also provided a perfectly satisfactory explanation of the number and type of bridging carbonyl modes, for example two edge-bridges in [Fe 3 (CO) 12 ], three edge-bridges in [Co 4 (CO) 12 ] and four face-bridges in [Rh 6 (CO) 16 ].…”

Binary Carbonyls, Carbonyls plus Hydrides, Carbonyls plus Phosphines, Cyclic Hydrocarbyls and Main-group Ligands without Acyclic Hydrocarbyls

“…93 The only structural determination is of [Fe 2 Os(CO) 12 ], 35 but x-ray studies on a number of phosphine derivatives of [FeRu 2 (CO) 12 ] and [Fe 2 Ru(CO) 12 ] have been carried out, 28 ' 32 ' 93 and their structures have been reviewed, 94 and compared with their homonuclear analogues. A continuum of geometries is observed, ranging from the idealized C 2v bridged structure of [Fe 3 (CO) 12 ], through D 3 structures, to the idealized D 3h form o f [Ru 3 (CO) 12 ] and [Os 3 (CO) 12 ].…”

“…These data have been taken as evidence for a proposed mechanism of fluxionality in these compounds, involving the intermediacy of an anti-cubeoctahedral complementary geometry of the carbonyl poly tope. 94 The situation is less favourable as regards one other potential series of neutral heteronuclear clusters, that of [M 4 (CO)i 2 ] (M = Co, Rh or Ir). Although phosphine derivatives of several members have been prepared, 77 " 81 the only structure determination is of [Co 2 Rh 2 (CO) n (PPh 3 )].…”