Characteristics of beryllium bonds; a QTAIM study

Abstract

The nature of beryllium bonds formed between BeX2 (X is H, F and Cl) and some Lewis bases have been investigated. The distribution of the Laplacian of electron density shows that there is a region of charge depletion around the Be atom, which, according to Laplacian complementary principal, can interact with a region of charge concentration of an atom in the base and form a beryllium bond. The molecular graphs of the investigated complexes indicate that beryllium in BeH2 and BeF2 can form “beryllium bonds” with O, N and P atoms but not with halogens. In addition, eight criteria based on QTAIM properties, including the values of electron density and its Laplacian at the BCP, penetration of beryllium and acceptor atom, charge, energy, volume and first atomic moment of beryllium atom, have been considered and compared with the corresponding ones in conventional hydrogen bonds. These bonds share many common features with very strong hydrogen bonds, however,some differences have also been observed.

Using beryllium bonds to change halogen bonds from traditional to chlorine-shared to ion-pair bonds

“…Studies of beryllium bonds in complexes between BeH 2 and HArF 13 have been reported, and the results analyzed using the QTAIM methodology. 14 Previously, we investigated the beryllium bonds formed between the acids BeX 2 , for X = H, F, Cl, and OH, and a variety of Lewis bases. 15 These bonds have bond critical points, and in some cases slightly negative energy densities, indicating partial covalent character.…”

Interplay of Hydrogen, Halogen, Lithium and Beryllium Bonds in Complexes of Thiirane

“…. .Y [63][64][65]. The Be atom, like H and Li, is also highly electropositive and therefore the interaction energies of beryllium bonds tend to have a substantial electrostatic component and are generally comparable in strength to very strong hydrogen bonds.…”

“…Electronic charge may also be transferred into the A-Be/A -Be antibonding orbital (σ * A-Be/A -Be ). The shift in charge densities greatly increase the covalent character of beryllium bonds [63,64] and may result in relatively high ρ bcp for these bonds compared to their hydrogen-bonded analogues [63].…”

A computational study of model beryllium-bonded complexes of oxirane and F-substituted oxiranes with BeX2 (X=H, Cl)

“…Some of these reported studies on beryllium bonding are in Refs. [11][12][13][14][15][16][17][18][19]. A particularly interesting finding is that beryllium bonds can change a weak halogen bond into a stronger interaction, with the cooperative effect of the beryllium bond increasing with the basicity of the Lewis base [17].…”

“…In some respects it is similar to hydrogen bonding -some researchers justifiably find merit in considering the Be atom as a hydrogen atom with a core of electrons [11,12]. It is however a stronger intermolecular interaction, exhibiting partial covalent character in some instances [11].…”