BeX2 induced C-H bond activation: A concise computational glance

Abstract

The effect of BeX2 (X = H, F, Cl, Br and CN) on the C-H bond activation of some aldehyde, ketone and imine molecules were assessed theoretically by the B3LYP/6–311++G(d,p) method. The interaction of BeX2 derivatives with oxygen atom in aldehydes and ketones as well as with nitrogen atom in imine molecules was studied. The interaction of beryllium atom with the carbonyl or imine functional groups stabilizes the conjugated bases after deprotonation which promotes C-H bond dissociation in all sample molecules. The acidity enhancement strongly depends on the ability of X moiety for charge distribution so that, the maximum acidity increasing is obtained by Be(CN)2 molecule. After deprotonation, charge distribution by Be(CN)2 leads stability of the conjugated base and as a result, increases the acidity. ΔHform and ΔGform (Enthalpies and Gibbs free energies of complex formation with BeX2), ΔHacid and ΔGacid (Enthalpies and Gibbs free energies of deprotonation process in the absence and presence of BeX2) were used for evaluating of acidity as the main parameter for C-H bond activation. Using these strategies, it was found that the beryllium compounds specially Be(CN)2 leads to activate C-H bonds in variety molecules and it can be used as a promising suitable catalyst for C-H functionalization organic syntheses.