Planar tetracoordinate fluorine atoms

Abstract

Unlike other atoms, a planar tetracoordinate fluorine atom is elusive. So far, there are no theoretical or experimental reports suggesting their existence. Herein, we introduce the first six combinations (FIn4+,...

σ-Aromaticity Planar Pentacoordinate Beryllium Atoms

“…Starting from the planar methane ( D 4 h ) proposed by Monkhorst in 1968, the effective electronic stabilization considerations (full delocalization of p z π electrons of the central atom and suitable ligand–ligand interactions) suggested by Hoffmann, Boldyrev, and Schleyer and co-workers ,, significantly promote the development of planar carbon chemistry. It is worth noting that numerous ptC and ptX (X = noncarbon atom) species have been explored theoretically, − detected by gas-phase photoelectron spectroscopy, − and even synthesized during the past half-century. − In contrast to planar tetracoordinate examples, the higher coordinated analogues are relatively scarce because of their much more critical structural and electronic design prerequisites. − ,− Nevertheless, a few successful isolated clusters [CAl 5 + and its heteroatom-substituted analogues and decorations of CBe 5 4– in CBe 5 Y n n –4 (Y = Li, H, Au; n = 2–5)] have been characterized as the global minima. − Note that the planar hypercoordinate motifs can also be embedded in the ground-state two-dimensional nanosheets. − These intriguing theoretical explorations strongly break the human being’s imagination and push the limit of chemical bonding. − , …”

“…The mature electronic design principles discussed above have harvested a few great examples for planar hypercoordinate species, − even extended to the highly negative fluorine atom . A strong electron-donating tendency and poor capability of forming delocalized bonds make planar hypercoordinate group 2 relatively scarce.…”

CSinGe4−n2+(n= 1–3): prospective systems containing planar tetracoordinate carbon (ptC)

“…Significantly, this rule can be extended to other elements, the extreme case being fluorine in FIn 4 + , FTl 4 + , FGaIn 3 + , FIn 2 Tl 2 + , FIn 3 Tl + , and FInTl 3 + systems with planar tetracoordinate orientations. 48 Using two strategies as suggested by Hoffmann and coworkers, many ptC systems were reported theoretically, but the experimental realization is limited. 3–9 In 1999, the mono-anionic CAl 4 − system was reported in the gas phase along with the ab initio computations for the bonding analysis.…”

“…However, this rule would give an idea for the modeling of new ptC systems theoretically as well as experimentally. Significantly, this rule can be extended to other elements, the extreme case being fluorine in FIn 48 Using two strategies as suggested by Hoffmann and coworkers, many ptC systems were reported theoretically, but the experimental realization is limited. [3][4][5][6][7][8][9] In 1999, the monoanionic CAl 4 À system was reported in the gas phase along with the ab initio computations for the bonding analysis.…”

BAl4Mg−/0/+: Global Minima with a Planar Tetracoordinate or Hypercoordinate Boron Atom

“…From the time that the concept of planar tetracoordinate carbon (ptC) emerged [1,2], it was extended not only to its group elements (Si, Ge, Sn, etc.) [3][4][5][6][7][8][9][10] but also to other elements such as B [11][12][13][14][15][16][17], Al [18,19], N [20][21][22], P [23], O [24], and lately even to the F atom [25]. There are two main reasons why experimentalists [5,6,[26][27][28][29][30][31][32][33] and theoreticians [2,[34][35][36][37][38][39][40][41][42][43] have put a great deal of effort into studying these special class of molecules: (i) ptC is a fundamental deviation from the conventional ideas of tetrahedral tetracoordinate carbon [44,…”