title: Dispersion Forces, Disproportionation, and Stable High-Valent Late Transition Metal Alkyls.
abstract: The transition metal tetra- and trinorbornyl bromide complexes, M(nor)4(M=Fe, Co, Ni) and Ni(nor)3Br (nor=1-bicyclo[2.2.1]hept-1-yl) and their homolytic fragmentations were studied computationally using hybrid density functional theory (DFT) at the B3PW91 and B3PW91-D3 dispersion-corrected levels. Experimental structures were well replicated; the dispersion correction resulted in shortened M-C bond lengths for the stable complexes, and it was found that Fe(nor)4receives a remarkable 45.9 kcal mol-1stabilization from the dispersion effects whereas the tetragonalized Co(nor)4shows stabilization of 38.3 kcal mol-1. Ni(nor)4was calculated to be highly tetragonalized with long Ni-C bonds, providing a rationale for its current synthetic inaccessibility. Isodesmic exchange evaluation for Fe(nor)4confirmed that dispersion force attraction between norbornyl substituents is fundamental to the stability of these species.
authors: Department of Chemistry, University of California, One Shields Avenue, Davis, CA, 95616, USA.
authors: David J
authors: DJ
authors: Liptrot
authors: Fukui Institute for Fundamental Chemistry, Kyoto University, Takano Nishi-Hiraki-Cho 34-4, Sakyo-ku, Kyoto, 606-8103, Japan.
authors: Jing-Dong
authors: JD
authors: Guo
authors: Fukui Institute for Fundamental Chemistry, Kyoto University, Takano Nishi-Hiraki-Cho 34-4, Sakyo-ku, Kyoto, 606-8103, Japan.
authors: Shigeru
authors: S
authors: Nagase
authors: Department of Chemistry, University of California, One Shields Avenue, Davis, CA, 95616, USA.
authors: Philip P
authors: PP
authors: Power
keywords: density functional calculations; dispersion forces; high oxidation states; organometallics; transition metals