Effect of Magnesium Bond on the Competition Between Hydrogen and Halogen Bonds and the Induction of Proton and Halogen Transfer

Abstract

HOX (X=Cl, Br, I, and At) can engage in either a H-bond (HB) or halogen bond (XB) with a base-like HCN, NH , and imidazole. Although the former is energetically preferred for X=Cl and Br, it is the XB that is more stable for At, with I showing little preference. MgY forms a Mg-bond with the O atom of HOX, which grows stronger in the order X=Cl<Br<I<At and Y=F<Cl<Br. When all three molecules are combined, both the Mg and the H/X bonds are cooperatively strengthened to a large degree. Rather than causing a reversal in the HB/XB competition, the Mg-bond acts primarily to amplify the natural preference within the dimer. The Mg-bond induces a certain degree of transfer from O to N of the bridging atom in the H/X bond. Comparison is also made with the effects of a Be-bond.

Tuning the Competition between Hydrogen and Tetrel Bonds by a Magnesium Bond

“…[29,30] By combining interactions that do not compete for the same binding sites, it is, in principle, possible to avoid or at least minimize ''synthon cross-over'', [31] thereby producing architectures of considerable complexity. [34][35][36][37][38][39][40][41][42][43] This is not only because HBs and XBs are similar in strength and properties, but also they are widely applicable to biochemistry and drug design. [33] There are many studies on the competition between various interactions, especially the competition between hydrogen and halogen bonds.…”

“…Beyond the well documented issue of the nature of the Lewis acid and base, [44] there are other important factors such as solvent polarity. [46][47][48][49][50][51][52][53][54][55][56] In a recent work, Xu et al observed the effect of a magnesium bond (Mg-bond) on the competition between HB and XB [38] and found that the Mg-bond enhances both the HB and XB, but the degree of this strengthening is different for the two. [46][47][48][49][50][51][52][53][54][55][56] In a recent work, Xu et al observed the effect of a magnesium bond (Mg-bond) on the competition between HB and XB [38] and found that the Mg-bond enhances both the HB and XB, but the degree of this strengthening is different for the two.…”

“…[33] There are many studies on the competition between various interactions, especially the competition between hydrogen and halogen bonds. [34][35][36][37][38][39][40][41][42][43] This is not only because HBs and XBs are similar in strength and properties, but also they are widely applicable to biochemistry and drug design. Alkorta et al studied HBs and XBs formed between hypohalous acid and three nitrogen-containing bases .…”

Comparison between Hydrogen and Halogen Bonds in Complexes of 6‐OX‐Fulvene with Pnicogen and Chalcogen Electron Donors

“…Cooperativity also affects the competition between HB and XB. For example, the presence of magnesium bonding has a positive synergistic effect on the strength of HB and XB, but the enhancing effect on both interactions is different . Of course, whether it is HB or XB, its strength depends mainly on the properties of Lewis acid and Lewis base.…”

“…For example, the presence of magnesium bonding has a positive synergistic effect on the strength of HB and XB, but the enhancing effect on both interactions is different. [38] Of course, whether it is HB or XB, its strength depends mainly on the properties of Lewis acid and Lewis base. Therefore, many studies have been conducted on the effects of Lewis acid and Lewis base on the competition between HB and XB.…”