Special Issue "Planar Tetracoordinate Carbon—Fifty Years and Beyond"

A special issue of Atoms (ISSN 2218-2004). This special issue belongs to the section "Quantum Chemistry, Computational Chemistry and Molecular Physics".

Deadline for manuscript submissions: 31 July 2021.

Special Issue Editors

Dr. Venkatesan S. Thimmakondu
E-Mail Website
Guest Editor
Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182, USA.
Interests: planar tetracoordinate carbon; astrochemistry; quantum chemistry; molecular spectroscopy
Dr. Krishnan Thirumoorthy
E-Mail Website
Guest Editor
Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Tamil Nadu, India
Interests: chiral recognition; planar tetracoordinate carbon; computational chemistry; role of chirality in biomolecules

Special Issue Information

Dear Colleagues,

In 1968, Monkhorst first mentioned the idea of planar tetracoordinate carbon (ptC) in the literature for a transition-state geometry. Later, in 1970, Hoffmann and co-workers had shown ways to stabilize molecules containing ptC atom. In the last fifty years, a plethora of molecules containing ptC have been theoretically characterized, and some experimentally detected. The concept of molecules with a ptC atom still enthralls both experimentalists and theoreticians, as it is a fundamental deviation from the tetrahedral tetracoordinate carbon atom, defined independently by van’t Hoff and Le Bel in 1874. Thus, ptC molecules can collectively be defined as “anti-van’t Hoff–Le Bel molecules”. Over a period of time, the idea has not only been extended to carbon group elements (Si, Ge, etc.) but also to other elements such as B, N, Al, and P and very recently even to the F atom. Molecules with a planar hypercoordinate carbon (phC) and other elements have also been witnessed in the literature over time. The core chemistry-based motivation in identifying these special classes of molecules stems from the fundamental fact that no two structural isomers of a given elemental composition behave in the same way chemically. Additionally, the idea of ptC or phC is a helpful tool to develop potential new 2D materials. The purpose of this Special Issue is to collect some recent trends in this subject area, as the field is continuously emerging and would supplement the existing literature. Therefore, we warmly welcome contributions from both experimental and theoretical scientific communities working in this field.

Dr. Venkatesan S. Thimmakondu
Dr. Krishnan Thirumoorthy
Guest Editors

Manuscript Submission Information

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  • planar tetracoordinate carbon
  • planar tetracoordinate silicon
  • planar hypercoordinate carbon
  • planar hypercoordinate silicon
  • planar pentacoordinate carbon
  • planar pentacoordinate silicon
  • 2D materials
  • anti-van’t Hoff–Le Bel molecules

Published Papers (1 paper)

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Open AccessArticle
CAl4Mg0/−: Global Minima with a Planar Tetracoordinate Carbon Atom
Atoms 2021, 9(2), 24; https://0-doi-org.brum.beds.ac.uk/10.3390/atoms9020024 - 09 Apr 2021
Viewed by 834
Isomers of CAl4Mg and CAl4Mg have been theoretically characterized for the first time. The most stable isomer for both the neutral and anion contain a planar tetracoordinate carbon (ptC) atom. Unlike the isovalent CAl4Be case, which [...] Read more.
Isomers of CAl4Mg and CAl4Mg have been theoretically characterized for the first time. The most stable isomer for both the neutral and anion contain a planar tetracoordinate carbon (ptC) atom. Unlike the isovalent CAl4Be case, which contains a planar pentacoordinate carbon atom as the global minimum geometry, replacing beryllium with magnesium makes the ptC isomer the global minimum due to increased ionic radii of magnesium. However, it is relatively easier to conduct experimental studies for CAl4Mg0/− as beryllium is toxic. While the neutral molecule containing the ptC atom follows the 18 valence electron rule, the anion breaks the rule with 19 valence electrons. The electron affinity of CAl4Mg is in the range of 1.96–2.05 eV. Both the global minima exhibit π/σ double aromaticity. Ab initio molecular dynamics simulations were carried out for both the global minima at 298 K for 10 ps to confirm their kinetic stability. Full article
(This article belongs to the Special Issue Planar Tetracoordinate Carbon—Fifty Years and Beyond)
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