A hydrocarbon dication with nonplanar hexacoordinated carbon

Hepta‐ and Octacoordinate Boron in Molecular Wheels of Eight‐ and Nine‐Atom Boron Clusters: Observation and Confirmation

“…[20,21] More highly coordinated planar carbon and other main-group atoms have been proposed. [13,14] Our work is the first confirmation of hepta-and octacoordinated boron atoms and demonstrates that s and p aromaticity are responsible for the highly unusual coordination environments. It should be emphasized that detailed understanding of novel molecular structures using concepts of chemistry will be increasingly important in nanotechnology as device features rapidly approach the atomic and molecular scale.…”

“…Thus, the B 8 2À and B 9 À molecules can be considered to be aromatic, each with six p electrons conforming to the (4n + 2) Hückel rule. The p aromaticity in SiB 8 , which is valence isoelectronic to B 9 À , was discussed by Minyaev et al [14] However, we believe that the B 8 2À and B 9 À molecules are not only p aromatic, but also s aromatic. The three s orbitals in each molecule (2e 1 ' and 2a 1 ' in B 8 2À ; 2e 1u and 2a 1g in B 9 À ), which describe bonding between the central atom and the ring, are also highly delocalized and look very similar to the p MOs, thus conferring s aromaticity on these clusters.…”

P33.07: Prenatal diagnosis of a foregut duplication cyst in the floor of the mouth

“…Thus, the B 8 2− and B 9 − molecules can be considered to be aromatic, each with six π electrons conforming to the (4 n +2) Hückel rule. The π aromaticity in SiB 8 , which is valence isoelectronic to B 9 − , was discussed by Minyaev et al14 However, we believe that the B 8 2− and B 9 − molecules are not only π aromatic, but also σ aromatic. The three σ orbitals in each molecule (2e 1 ′ and 2a 1 ′ in B 8 2− ; 2e 1u and 2a 1g in B 9 − ), which describe bonding between the central atom and the ring, are also highly delocalized and look very similar to the π MOs, thus conferring σ aromaticity on these clusters.…”

Chalcogenborines and Derivatives: Probing the Origin of Relative Thermodynamic Stabilities

“…Earlier, ab initio and DFT calculations revealed a significant aromatic stabilization was achieved by 1,2‐dihydro‐1,2‐oxaborines . However, a subsequent comparison between the parent 1,2‐BO and benzene declared that the former was far less aromatic than the latter based on the nucleus‐independent chemical shift (NICS) calculations (i. e., NICS(1) zz =−16.60 vs −29.68 ppm, respectively) and NICS(1)=−6.8 vs −10.4 ppm, respectively) .…”

“…Meanwhile, few examples of 1,2‐thiaborine, a heavier congener of 1,2‐oxaborine, were also synthesized . In 2001, Ruslan M. Minyaev and co‐workers first studied relative thermodynamic stability and aromatic stabilization of the mono BO‐doped isomers of the oxaborine class (here called BO isomers) . They predicted based on ab initio and DFT calculations that among the three BO isomers, 1,2‐BO isomer was the most stable, followed by the 1,4‐BO isomer, and 1,3‐BO isomer was the least stable.…”