In Silico Analysis of the Electronic Delocalization in Some Double Fused-Ring Metallabenzenes

Abstract

In the current work, some metallabenzenes with one and several fused rings were analyzed in terms of their electronic delocalization. These fused-ring metallabenzenes are known as metallabenzenoids, and their aromatic character is not free of controversy. The systems of the current work were designed from crystallographic data of some synthesized molecules, and their electronic delocalization (aromaticity) was computationally examined in terms of the molecular orbital analysis (Hückel’s rule), the induced magnetic field, and ring currents. The computational evidence allows us to understand if these molecules are or are not aromatic compounds.

Metallaborazines: To Be or Not To Be Delocalized

“…Isosurfaces of the z-component of the induced magnetic field, B z ind , were employed as a measure of the magnetic response and it is equivalent to the z-component of the NICS (also known as NICS zz ). B z ind and B z ind have been employed in several kinds of molecules such as borazine and other metallacycles. − Also, the profiles of B z ind (and NICS) were computed for a numerical comparison between the molecules. The profiles’ tensors were computed with the Gaussian 09 program with the PBE0 functional ,, and the Jorge-atzp basis .…”

In Silico Analysis of the Aromaticity of Some Carbo-Metallabenzenes and Carbo-Dimetallabenzenes (Carbo-mers Proposed from Metallabenzenes)

“…Diatropic current densities were induced in a counterclockwise direction over the carbons, and in the inner part of the ring, a paratropic current density was sustained. This behavior was analogous to the benzene molecule and then it could be categorized as aromatic 16 based on this magnetic criterion. This behavior was also found in some system proposed here.…”

“…The most employed index is NICS (nucleus independent chemical shifts) developed by Schleyer et al in 1996. With NICS, the aromaticity of some metallacycles was analyzed. − Similar to NICS, the induced magnetic field ( B ind ) has been employed as aromaticity’s descriptor and, with the B ind , the diatropic character (associated with aromaticity) was determined in some metallacycles including some fused-cycles, metallaborazines, and five-membered rings (5MR). , Finally, for a deeper appreciation of the metallacycle chemistry, some reviews are available. ,, …”

The spin–orbit effects on platinabenzene: a ring current and electron delocalization approach

“…[22][23][24] Even more for extended systems. 25,26 These molecules experience similar aromatic stabilization as benzene, non-alternating bond lengths, 1 H NMR downfield-shifted signals, and electrophilic aromatic substitutions.…”