Bonding Analysis of Compounds with Unusual Coordination of Carbon: Proposed Symmetric Systems with Six-Coordinate Carbon

Trindle C., ALTUN Z., BLEDA E. A.

MOLECULES, vol.25, no.17, 2020 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Review
  • Volume: 25 Issue: 17
  • Publication Date: 2020
  • Doi Number: 10.3390/molecules25173937
  • Journal Name: MOLECULES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Agricultural & Environmental Science Database, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Communication Abstracts, EMBASE, MEDLINE, Metadex, Veterinary Science Database, Directory of Open Access Journals, Civil Engineering Abstracts
  • Keywords: AIM modeling, electron localization function, non-covalent interaction, carbon hypercoordination, PLANAR TETRACOORDINATE CARBON, PYRAMIDAL HEXAMETHYLBENZENE DICATION, HEXACOORDINATE CARBON, THEORETICAL DESIGN, ATOMS, BEARING, BORON, SPECTROSCOPY, MOLECULES, CHEMISTRY
  • Marmara University Affiliated: Yes

Abstract

The possibility of carbon tetravalence in geometries other than tetrahedral and of carbon hypervalence has been taken seriously since the 1970s. Computational modeling and subsequent experimental validation have established the existence of molecules with carbon atoms with planar tetravalence and as many as six objects in carbon's coordination sphere. In this work, we develop insight into the nature of bonding to carbon in these unusual environs as provided by Bader's Atoms in Molecules (AIM) analysis of the electron density, along with the electron localization function (ELF) and the non-covalent index (NCI). We review several well-established systems (spiropentadiene dication, hexamethyl benzene dication, dimethanospiro[2.2]octaplane dication, and 1,8-dimethoxy-9-dimethoxyanthracene cation) and propose new D-2d-symmetric variants of a hexacoordinated species.