Alkaline-earth (Be, Mg and Ca) bonds at the origin of huge acidity enhancements

Montero‐Campillo, M. Merced; Sanz, Pablo; Mó, Otília; Yáñez, Manuel; Alkorta, Ibón; Elguero, José

doi:10.1039/c7cp07891a

Cited by 36 publications

(30 citation statements)

References 28 publications

(25 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reason behind this huge effect on the water acidity relies on the large binding energy differences between neutral and charged complexes. Previous works,,,,, have shown precisely that this binding enthalpy difference is related to the acidity enhancement through a thermodynamic cycle analogous to the one shown in Scheme .…”

Section: Resultsmentioning

confidence: 82%

“…It is well‐known that in molecular clusters linked by hydrogen bonds, from dimers onwards, the thermodynamic acid‐base properties of the terminal monomers are substantially modified, as for instance in (HCN) n and (HNC) n . We have reported the possibility of modulating the acidity of imidazoles and pyrazoles by means of beryllium bonds; the huge acidity increases produced by alkaline‐earth bonds; the large proton affinity (PA) enhancements triggered by non‐covalent interactions; and the changes on the acidity and basicity of disiloxane due to the formation of complexes with Lewis acids and Lewis bases …”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Enhancement of Thermodynamic Gas‐Phase Acidity and Basicity of Water by Means of Secondary Interactions

2018

Self Cite

View full text Add to dashboard Cite

A series of A⋅water, B⋅water complexes (A=acid, B=base) are studied at the G4 level of theory to show that water acidity or basicity can be modulated by non-covalent interactions. Protic and non-protic acids interacting with water form hydrogen bonds or other kinds of non-covalent interactions, respectively, that may dramatically change the acidity of water up to almost 360 kJ ⋅ mol in terms of enthalpy. Similarly, hydrogen bonds responsible for the interaction between typical small nitrogen-containing Lewis bases and water can enhance the proton affinity of water by almost 300 kJ ⋅ mol . Our results reveal that these large enhancements are linearly related with the binding energy of the charged complexes, and are determined by the Lewis acid-base properties of the molecule involved in the interaction, allowing a quite precise modulation of the corresponding acid-base properties of water.

show abstract

Section: Resultsmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Enhancement of Thermodynamic Gas‐Phase Acidity and Basicity of Water by Means of Secondary Interactions

2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…The lithium bond may be probably classified as the σ‐hole bond however it is characterized by numerous unique properties . For the elements of group 2 the beryllium bond and the magnesium bond were analysed but they were not rather classified as the σ‐hole or π‐hole bonds. In a recent study the regions of the positive electrostatic potential were discussed in various moieties where Mg‐centre was characterized by different coordination, up to six …”

Section: Introductionmentioning

confidence: 99%

“…In another study different approaches were used to describe the magnesium bond; QTAIM, the ELF (Electron Localization Function) method and the NBO (Natural Bond Orbital) method. Very recently the beryllium, magnesium and calcium divalent centres were discussed which interact with the Lewis base species that leads to deformations of initial linear structure of their corresponding moieties …”

Section: Introductionmentioning

confidence: 99%

Coordination of Be and Mg Centres by HCN Ligands – Be…N and Mg…N Interactions

Grabowski

2018

ChemPhysChem

View full text Add to dashboard Cite

ωB97XD/aug-cc-pVTZ calculations were performed for clusters of Z cations (Z=Be and Mg) and HCN molecules (up to six molecules). The clusters of Be(CH ) and Mg(CH ) with HCN species were also calculated to analyse the influence of the Be/Mg-C formally covalent bonds on interactions of Be or Mg centre with ligands. The beryllium and magnesium centres possess different areas of a positive electrostatic potential that depend on a number of HCN ligands in the cluster considered. Numerous correlations between geometrical, energetic and topological parameters of the clusters considered are discussed since various theoretical approaches are applied; Quantum Theory of 'Atoms in Molecules', Natural Bond Orbital method and decomposition of the energy of interaction. The Be/Mg…N interactions classified as beryllium and magnesium bonds possess numerous characteristics which are known for the hydrogen bonds. Different types of coordination of Be and Mg centres analysed here exist also in crystal structures.

show abstract

“…Even more recently interesting cases were described in which a network of conjugated bonds strongly hinders a hydrogen bond, phenomenon which was called Resonance Impaired Hydrogen Bonds (RIHB) [20]. Also recently, it was shown that Mg can also yield magnesium bonds similar to the beryllium ones [21]; but, what is more important and unexpected, in some specific cases the magnesium bonds were found to be of similar strength or even stronger than the beryllium bond analogues [22]. The question we would like to address in this paper is whether the intramolecular magnesium bonds also share some similarities with the corresponding intramolecular beryllium bonds and if some dissimilarities appear, what is the origin.…”

Section: Introductionmentioning

confidence: 99%

Intramolecular magnesium bonds in malonaldehyde-like systems: a critical view of the resonance-assisted phenomena

et al. 2018

Self Cite

View full text Add to dashboard Cite

Through the use of high-level G4-theory calculations we have investigated the structure, stability and bonding of a set of Mg derivatives formed by replacing the-OH group of malonaldehyde or only the hydrogen atom of this group by a-MgH group. To give insight on the resonance-assisted phenomenon, which might be involved in the stabilization of these compounds, we also included the corresponding saturated analogues in our survey. The effect of the rigidity of the molecular framework was considered by analyzing the Mg-derivatives of (Z)-4-(hydroxymethylene)cyclobut-2enone, obtained through the same substitutions mentioned above. The effect of replacing the carbonyl group by an imino group was also contemplated. In all cases, the global minimum is a cyclic conformer stabilized through the formation of rather strong intramolecular magnesium bonds. The strength of these interactions is directly related with the intrinsic basicity of the carbonyl group (or the imino group) and the intrinsic acidity of the-MgH group, rather than with a resonance-assisted phenomenon. As a matter of fact, for all the investigated systems, the conclusion is that resonance in the cyclic conformer is directly correlated with the strength of the intramolecular magnesium bond, and not vice-versa. Interestingly, the strength and characteristics of these interactions for these Mg-containing derivatives are very similar to those of the corresponding Be-containing analogues.

show abstract

Alkaline-earth (Be, Mg and Ca) bonds at the origin of huge acidity enhancements

Abstract: Conventional bases become very strong acids upon association with alkaline-earth derivatives MX2 (M = Be, Mg and Ca).

Cited by 36 publications

References 28 publications

Enhancement of Thermodynamic Gas‐Phase Acidity and Basicity of Water by Means of Secondary Interactions

Enhancement of Thermodynamic Gas‐Phase Acidity and Basicity of Water by Means of Secondary Interactions

Coordination of Be and Mg Centres by HCN Ligands – Be…N and Mg…N Interactions

Intramolecular magnesium bonds in malonaldehyde-like systems: a critical view of the resonance-assisted phenomena

Contact Info

Product

Resources

About