Behavior of carboxylic acids upon complexation with beryllium compounds.

Area of Science:

• * Computational Chemistry
• * Inorganic Chemistry
• * Physical Chemistry

Background:

• * Beryllium bonds were previously shown to enhance acidity and alter aromaticity in squaric acid derivatives.
• * The general applicability of this phenomenon to other carboxylic acids remained unexplored.

Purpose of the Study:

• * To investigate if complexation with beryllium compounds generally enhances the acidity of carboxylic acids.
• * To explore the structural and electronic factors influencing the stability and properties of these complexes.

Main Methods:

• * Density functional theory (DFT) calculations were employed.
• * A series of representative carboxylic acids (formic, acetic, propanoic, benzoic, oxalic) and beryllium compounds (BeX2, X = H, F, Cl) were studied.

Main Results:

• * Complexes featuring dihydrogen bonds or OH···X interactions were found to be the most stable.
• * All studied carboxylic acid complexes with BeX2 exhibited significantly enhanced acidity compared to their free forms.
• * Electron density topology analysis elucidated the mechanisms behind the observed acidity enhancement.
• * A novel neutral complex, [RCOO:BeH], was observed to form spontaneously with the loss of H2 when using BeH2.

Conclusions:

• * Complexation with beryllium compounds is a general strategy for enhancing carboxylic acid acidity.
• * The stability and properties of these complexes are governed by specific weak interactions.
• * The formation of [RCOO:BeH] complexes represents a notable reactivity pathway for carboxylic acids with beryllium dihydride.