title: Experimental and theoretical charge-density study of a tetranuclear cobalt carbonyl complex.
abstract: Details of the complex bonding environment present in the molecular centre of an alkyne-bridged dicobalt complex have been examined using a combination of experimental and theoretical charge-density modelling for two compounds which share a central Co(2)C(2) tetrahedral moiety as their common motif. Topological analysis of the experimental electron density illustrates the problem of separating the Co-C bond-critical points (b.c.p.s) from the intervening ring-critical point (r.c.p.), due largely to the flat nature of the electron density in the CoC(2) triangles. Such a separation of critical points is immediately obtained from a topological analysis of the theoretical electron density as well as from the multipole-projected theoretical density; however, the addition of random noise to the theoretical structure factors prior to multipole modelling leads to a failure in consistently distinguishing two b.c.p.s and one r.c.p. in such close proximity within the particular environment of this Co(2)C(2) centre.
authors.affiliation: Department of Chemistry, Aarhus University, Denmark. jacobo@chem.au.dk
authors.forename: Jacob
authors.initials: J
authors.lastname: Overgaard
authors.forename: Jamie A
authors.initials: JA
authors.lastname: Platts
authors.forename: Bo B
authors.initials: BB
authors.lastname: Iversen