Carbon rings decorated with group 14 elements: new aromatic clusters containing planar tetracoordinate carbon

Abstract

A simple and chemically intuitive approach is used to design ptC-containing E–C clusters (E = Si–Pb).

Flat crown ethers with planar tetracoordinate carbon atoms

“…The concept of molecules with a planar tetracoordinate carbon (ptC) [ 1,2 ] atom is an inspiration to all chemists [ 3–15 ] despite it breaking one of the fundamental paradigms of organic chemistry—that is, tetrahedral tetracoordinate carbon. [ 16,17 ] Experimental and theoretical confirmation of pentaatomic ptC species (CAl, CAl 3 Si −/0 , CAl 3 Ge −/0 , CAl, etc.,) [ 18–21 ] has provided some momentum in the search of these molecules in the gas phase.…”

Searching for double σ- and π-aromaticity in borazine derivatives

“…We used an initial population of 5X (X ¼ number of atoms of the system), this small population showed to be enough to successfully identify the lowest energy structures of many clusters and molecules. [39][40][41][42][43] Additionally, we evaluated the dynamic behavior of compounds 4, 6 and 8 (for an insight into their kinetic stability), employing Born-Oppenheimer molecular dynamic (BOMD) simulations. 44 Geometry optimizations, vibrational frequency and BOMD calculations were carried out using the Gaussian 16 program.…”

Analysis of Local and Global Aromaticity in Si₃C₅ and Si₄C₈ Clusters. Aromatic Species Containing Planar Tetracoordinate Carbon

“…Previously, some of the authors of this work had designed a series of ptC global minima composed of carbon and heavier atoms of group 14 of the periodic table [63][64][65]. The design strategy consisted of replacing three consecutive protons from an aromatic hydrocarbon by one E2 4+ fragment (E=Si-Pb), favoring the preservation of the -aromatic circuits of the parent aromatic hydrocarbons (see Scheme 1) [63]. Interestingly, the systems Si3C5, Ge3C5, Si4C8 and Ge4C8 (C5H5 -and C8H6 2-derivatives) contain one or two ptCs in their lowest energy structures.…”