Erythronium Bonds: Noncovalent Interactions Involving Group 5 Elements As Electron-Density Acceptors.

Analyses of the Cambridge Structural Database and theoretical calculations (PBE0-D3/def2-TZVP level, atoms-in-molecules, natural bond orbital studies) prove the formation of net attractive noncovalent interactions between group 5 elements and electron-rich atoms (neutral or anionic). These kinds of bonding are markedly different from coordination bonds formed by the same elements and possess the distinctive features of sigma-hole interactions. The term erythronium bond is proposed to denote these bonds. X-ray structures of vanadate-dependent bromoperoxidases show that these interactions are present also in biological systems. In this work, the term erythronium bond (EyB) is proposed to name an attractive noncovalent interaction between any electrophilic element of group 5 and electron-rich atoms (Lewis bases or anions).**image