Planar pentacoordinate carbon in CAl5(+): a global minimum.
We report evidence for the first global-minimum structure having a planar pentacoordinate carbon. High-level ab initio computations and quantum molecular dynamics simulations at 300 and 400 K reveal that the most stable CAl5(+) isomer has D5h symmetry and is approximately 3.80 kcal/mol lower in energy than the second most stable alternative. The latter has a nonplanar structure based on a tetrahedral CAl4 moiety. The unexpectedly high proclivity for two-dimensional chemical bonding of the carbon in D5h CAl5(+), the robust thermal stability indicated computationally, and its mass spectrometric detection suggest that experimental characterization of this planar pentacoordinate carbon cation at room temperature is a likely prospect.
Pei
Yong
Y
Department of Chemistry and Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA.
An
Wei
W
Ito
Keigo
K
Schleyer
Paul von Ragué
Pv
Zeng
Xiao Cheng
XC