Planar Hexacoordinate Carbons: Half Covalent, Half Ionic

• Published in: Angewandte Chemie International Edition Vol. 60; no. 16; pp. 8700 - 8704
• Main Authors: Leyva‐Parra, Luis, Diego, Luz, Yañez, Osvaldo, Inostroza, Diego, Barroso, Jorge, Vásquez‐Espinal, Alejandro, Merino, Gabriel, Tiznado, William
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 12.04.2021
• Edition: International ed. in English
• Subjects: Alkali metals; Carbon; Cations; Chemical bonds; Electronegativity; Electrostatic properties; Hypercoordination; Hypervalence; Metal ions; Planar hexacoordinate carbon; Planar tetracoordinate carbon; Hypercoordination; Planar tetracoordinate carbon; Planar hexacoordinate carbon; Hypervalence
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202100940

Herein, the first global minima containing a planar hexacoordinate carbon (phC) atom are reported. The fifteen structures belong to the CE3M3+ (E=S–Te and M=Li–Cs) series and satisfy both geometric and electronic criteria to be considered as a true phC. The design strategy consisted of replacing oxygen in the D3h CO3Li3+ structure with heavy and less electronegative chalcogens, inducing a negative charge on the C atom and an attractive electrostatic interaction between C and the alkali‐metal cations. The chemical bonding analyses indicate that carbon is covalently bonded to three chalcogens and ionically connected to the three alkali metals. Fifteen global minima of the CE3M3+ (E=S–Te and M=Li–Cs) series contain a true planar hexacoordinate carbon. The chemical bonding analyses indicate that the carbon atom is covalently bonded to three chalcogens and ionically connected to the three alkali metals.