Strong carbon – noble gas covalent bond and fluxionality in hypercoordinate compounds

Abstract

Thermodynamic, kinetic, and chemical bond analysis at the coupled cluster level has been carried out for a series of hypercoordinated carbon compounds with formula CH4Ng2+ (Ng = He–Rn).

Planar tetracoordinate beryllium compounds with a partially covalent Be–Ng bond

“…3 There are different types of compounds containing noble gases; among them, compounds with covalent bonds between M and Ng atoms stand out. Here, M represents an electrondeficient atom or molecule that facilitates the charge transfer from the full shell of the noble gas to an empty orbital of M. Some of these systems have recently been reported as hypercoordinated compounds in which the noble gases form covalent bonds with BH 4 +4 and CH 4 2+ , 5 the latter being the first fluxional compound containing a noble gas. Both BH 4 + and CH 4 2+ are electron-deficient compounds with single B-H and C-H bonds, a delocalized 3c-2e bond, and an empty p orbital (on B and C), allowing electron donation from the noble gas.…”

Exploring the Nature of Chemical Bonding between Noble Gases and Hypercoordinate Group 13 Compounds: Beyond Boron

“…Recent studies show that noble gases can react with hypercoordinated compounds to form new molecules with E–Ng covalent bonds, where E represents the hypercoordinated atom (generally an element belonging to the main group). − The reason for the affinity of noble gases (mostly from Ar to Rn) is the relatively low ionization energies when compared to He and Ne, which enables them to donate charge where are required . This leads to the formation of coordinated covalent bonds between a main group element and a noble gas .…”

“…This leads to the formation of coordinated covalent bonds between a main group element and a noble gas . Some examples of compounds containing Be–Ng, B–Ng, ,,− and C–Ng , bonds can be found in the literature. The chemical bond of those molecules has been systematically studied, even with the possibility of the formation of C–He and C–Ne bonds at very low temperatures.…”

Chemical Aristocracy: He3 Dication and Analogous Noble-Gas-Exclusive Covalent Compounds

“…While diatomic molecular dications containing noble gases, especially those containing helium, have been extensively investigated, , the exploration of dications with more than two atoms has been relatively limited. Among these systems (see Figure A), structures analogous to acetylene containing helium (HeCCHe 2+ ) and neon (NeCCNe 2+ ) are noteworthy. , More recently, novel CH 4 Ng 2+ (Ng = He–Rn) dications resembling methanium (CH 5 + ) and showcasing strong C–Ng bonds have been proposed . The design of these systems usually involves replacing a hydrogen atom with Ng + or, alternatively, substituting a hydrogen ion with Ng 2+ within the molecular structure.…”

“… 16 , 17 More recently, novel CH 4 Ng 2+ (Ng = He–Rn) dications resembling methanium (CH 5 + ) and showcasing strong C–Ng bonds have been proposed. 18 The design of these systems usually involves replacing a hydrogen atom with Ng + or, alternatively, substituting a hydrogen ion with Ng 2+ within the molecular structure. The inherent challenges of conducting experimental studies in helium molecular ion chemistry, coupled with the computational tractability of these small-sized compounds, highlight the paramount significance of theoretical investigations in furthering our comprehension and predictive potential within this domain.…”